WorldWideScience

Sample records for bactericides

  1. THE BACTERICIDAL ACTION OF SYNTHETIC DETERGENTS.

    Science.gov (United States)

    Baker, Z; Harrison, R W; Miller, B F

    1941-11-30

    1. The bactericidal action of a number of anionic and cationic synthetic detergents on four Gram-positive and three Gram-negative bacteria has been investigated. 2. Cationic detergents, as a group, were found to exhibit marked bactericidal effects on Gram-positive microorganisms and somewhat less pronounced action on Gram-negative organisms. 3. The anionic detergents were germicidal only against the Gram-positive organisms, and they were considerably less effective than the cationic compounds. Of the anionic detergents, the most active one was an alkyl sulfate derived from a branched-chain, secondary alcohol. 4. Correlations between bactericidal action and inhibition of bacterial metabolism, and also between bactericidal action and chemical structure of the detergents are discussed.

  2. EVALUATION OF BACTERICIDAL EFFECTIVENESS OF BENZALKONIUM CHLORIDE

    OpenAIRE

    K. Imandel; M.B. Shaywaard; F. Mobaraki

    1996-01-01

    Benzalkonium chloride is a quaternary ammounium Compounds derivative under different names such as Afxhang, Hamoon, Mahan etc, which have great and expanded use in sanitation and medical affairs. Bactericidal activity of these disinfectants was fulfilled according to National Standard Method No.2842 on Staph. Aureus, Sal. Typhimouium and E. coli. This laboratory test showed that, except Mahan that has not bactericidal efficacy on E.coli at concentration 0.4 percent, other disinfectants under ...

  3. EVALUATION OF BACTERICIDAL EFFECTIVENESS OF BENZALKONIUM CHLORIDE

    Directory of Open Access Journals (Sweden)

    K. Imandel

    1996-06-01

    Full Text Available Benzalkonium chloride is a quaternary ammounium Compounds derivative under different names such as Afxhang, Hamoon, Mahan etc, which have great and expanded use in sanitation and medical affairs. Bactericidal activity of these disinfectants was fulfilled according to National Standard Method No.2842 on Staph. Aureus, Sal. Typhimouium and E. coli. This laboratory test showed that, except Mahan that has not bactericidal efficacy on E.coli at concentration 0.4 percent, other disinfectants under the study in concentrations of 0.4, 0.8, 1, 1.2 percent have reliable antibacterial properties, and bacterial resistance to benzalkonium chloride has not occurred yet.

  4. Bactericidal properties of pradofloxacin against veterinary pathogens.

    Science.gov (United States)

    Silley, Peter; Stephan, Bernd; Greife, Heinrich A; Pridmore, Andrew

    2012-05-25

    Pradofloxacin is a new veterinary 8-cyano-fluoroquinolone developed for use against bacterial infections in dogs and cats involving both aerobic and anaerobic bacteria. The minimal bactericidal concentrations have been determined against clinical isolates of Staphylococcus pseudintermedius, Staphylococcus aureus, Escherichia coli, Pasteurella multocida, Streptococcus canis, Proteus spp., Fusobacterium spp., Porphyromonas gingivalis and Prevotella species. A subset of these species was selected, and the in vitro rate of kill by pradofloxacin was determined. For 27 of the 30 tested aerobic strains the pradofloxacin MBC was within two doubling dilutions of the MIC. For the remaining strains, the MIC and MBC were within three to four doubling dilutions. Pradofloxacin also demonstrated bactericidal activity against all anaerobic strains, and the MBC was equal to the MIC for four of the strains, within 1 doubling dilution for three strains, within 2 dilutions for a further 3 strains and within 3 dilutions for the remaining five strains. As pradofloxacin concentration was increased, a faster rate of killing was observed; bactericidal effects were seen in all cases at concentrations ≤ 0.25 μg/mL. The bactericidal activity against the anaerobic strains was marked, of particular relevance was the complete absence of regrowth even at 48 h at concentrations as low as 0.125 μg/mL. In conclusion, pradofloxacin exhibits clear bactericidal activity in terms of MBC and kill kinetics against aerobic and anaerobic clinical isolates from dogs and cats at concentrations that are greatly exceeded within the systemic circulation after administration of the recommended therapeutic doses to the target animals. It is expected that such a rapid rate of kill will play a significant role in clinical efficacy. These data demonstrate the complete and rapid killing of anaerobic bacteria by a veterinary 8-cyano-fluoroquinolone.

  5. Bacteriophages as Bactericides in Plant Protection

    Directory of Open Access Journals (Sweden)

    Aleksa Obradović

    2009-01-01

    Full Text Available Control of plant pathogenic bacteria is a serious problem in production of many agricultural crops. High multiplication rate, adaptability and life inside plant tissue make bacteria unsuitable and inaccessible for most of control measures. Consequently, the list of bactericides available for plant protection is very short. Lately, biological control measures have been intensively studied as a potential solution of the problem. Investigation of bacteriophages,viruses that attack bacteria, is a fast-expanding area of research in plant protection. Several experiments have shown that they can be used as a very efficient tool for control of plant pathogenic bacteria. The fact that they are widespread natural bacterial enemies, simple for cultivation and management, host-specific, suitable for integration with other control practices, human and environment friendly, provide a great advantage for the application of phages over other bactericides.

  6. Bordetella parapertussis Circumvents Neutrophil Extracellular Bactericidal Mechanisms

    Science.gov (United States)

    Gorgojo, Juan; Scharrig, Emilia; Gómez, Ricardo M.; Harvill, Eric T.; Rodríguez, Maria Eugenia

    2017-01-01

    B. parapertussis is a whooping cough etiological agent with the ability to evade the immune response induced by pertussis vaccines. We previously demonstrated that in the absence of opsonic antibodies B. parapertussis hampers phagocytosis by neutrophils and macrophages and, when phagocytosed, blocks intracellular killing by interfering with phagolysosomal fusion. But neutrophils can kill and/or immobilize extracellular bacteria through non-phagocytic mechanisms such as degranulation and neutrophil extracellular traps (NETs). In this study we demonstrated that B. parapertussis also has the ability to circumvent these two neutrophil extracellular bactericidal activities. The lack of neutrophil degranulation was found dependent on the O antigen that targets the bacteria to cell lipid rafts, eventually avoiding the fusion of nascent phagosomes with specific and azurophilic granules. IgG opsonization overcame this inhibition of neutrophil degranulation. We further observed that B. parapertussis did not induce NETs release in resting neutrophils and inhibited NETs formation in response to phorbol myristate acetate (PMA) stimulation by a mechanism dependent on adenylate cyclase toxin (CyaA)-mediated inhibition of reactive oxygen species (ROS) generation. Thus, B. parapertussis modulates neutrophil bactericidal activity through two different mechanisms, one related to the lack of proper NETs-inducer stimuli and the other one related to an active inhibitory mechanism. Together with previous results these data suggest that B. parapertussis has the ability to subvert the main neutrophil bactericidal functions, inhibiting efficient clearance in non-immune hosts. PMID:28095485

  7. Electrospun biodegradable polymers loaded with bactericide agents

    Directory of Open Access Journals (Sweden)

    Ramaz Katsarava

    2016-03-01

    Full Text Available Development of materials with an antimicrobial activity is fundamental for different sectors, including medicine and health care, water and air treatment, and food packaging. Electrospinning is a versatile and economic technique that allows the incorporation of different natural, industrial, and clinical agents into a wide variety of polymers and blends in the form of micro/nanofibers. Furthermore, the technique is versatile since different constructs (e.g. those derived from single electrospinning, co-electrospinning, coaxial electrospinning, and miniemulsion electrospinning can be obtained to influence the ability to load agents with different characteristics and stability and to modify the release behaviour. Furthermore, antimicrobial agents can be loaded during the electrospinning process or by a subsequent coating process. In order to the mitigate burst release effect, it is possible to encapsulate the selected drug into inorganic nanotubes and nanoparticles, as well as in organic cyclodextrine polysaccharides. In the same way, processes that involve covalent linkage of bactericide agents during surface treatment of electrospun samples may also be considered. The present review is focused on more recent works concerning the electrospinning of antimicrobial polymers. These include chitosan and common biodegradable polymers with activity caused by the specific load of agents such as metal and metal oxide particles, quaternary ammonium compounds, hydantoin compounds, antibiotics, common organic bactericides, and bacteriophages.

  8. Bacteria survival probability in bactericidal filter paper.

    Science.gov (United States)

    Mansur-Azzam, Nura; Hosseinidoust, Zeinab; Woo, Su Gyeong; Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2014-05-01

    Bactericidal filter papers offer the simplicity of gravity filtration to simultaneously eradicate microbial contaminants and particulates. We previously detailed the development of biocidal block copolymer micelles that could be immobilized on a filter paper to actively eradicate bacteria. Despite the many advantages offered by this system, its widespread use is hindered by its unknown mechanism of action which can result in non-reproducible outcomes. In this work, we sought to investigate the mechanism by which a certain percentage of Escherichia coli cells survived when passing through the bactericidal filter paper. Through the process of elimination, the possibility that the bacterial survival probability was controlled by the initial bacterial load or the existence of resistant sub-populations of E. coli was dismissed. It was observed that increasing the thickness or the number of layers of the filter significantly decreased bacterial survival probability for the biocidal filter paper but did not affect the efficiency of the blank filter paper (no biocide). The survival probability of bacteria passing through the antibacterial filter paper appeared to depend strongly on the number of collision between each bacterium and the biocide-loaded micelles. It was thus hypothesized that during each collision a certain number of biocide molecules were directly transferred from the hydrophobic core of the micelle to the bacterial lipid bilayer membrane. Therefore, each bacterium must encounter a certain number of collisions to take up enough biocide to kill the cell and cells that do not undergo the threshold number of collisions are expected to survive.

  9. Bactericidal antibiotics induce programmed metabolic toxicity

    Directory of Open Access Journals (Sweden)

    Aislinn D. Rowan

    2016-03-01

    Full Text Available The misuse of antibiotics has led to the development and spread of antibiotic resistance in clinically important pathogens. These resistant infections are having a significant impact on treatment outcomes and contribute to approximately 25,000 deaths in the U.S. annually. If additional therapeutic options are not identified, the number of annual deaths is predicted to rise to 317,000 in North America and 10,000,000 worldwide by 2050. Identifying therapeutic methodologies that utilize our antibiotic arsenal more effectively is one potential way to extend the useful lifespan of our current antibiotics. Recent studies have indicated that modulating metabolic activity is one possible strategy that can impact the efficacy of antibiotic therapy. In this review, we will address recent advances in our knowledge about the impacts of bacterial metabolism on antibiotic effectiveness and the impacts of antibiotics on bacterial metabolism. We will particularly focus on two studies, Lobritz, et al. (PNAS, 112(27: 8173-8180 and Belenky et al. (Cell Reports, 13(5: 968–980 that together demonstrate that bactericidal antibiotics induce metabolic perturbations that are linked to and required for bactericidal antibiotic toxicity.

  10. Bactericidal activity of partially oxidized nanodiamonds.

    Science.gov (United States)

    Wehling, Julia; Dringen, Ralf; Zare, Richard N; Maas, Michael; Rezwan, Kurosch

    2014-06-24

    Nanodiamonds are a class of carbon-based nanoparticles that are rapidly gaining attention, particularly for biomedical applications, i.e., as drug carriers, for bioimaging, or as implant coatings. Nanodiamonds have generally been considered biocompatible with a broad variety of eukaryotic cells. We show that, depending on their surface composition, nanodiamonds kill Gram-positive and -negative bacteria rapidly and efficiently. We investigated six different types of nanodiamonds exhibiting diverse oxygen-containing surface groups that were created using standard pretreatment methods for forming nanodiamond dispersions. Our experiments suggest that the antibacterial activity of nanodiamond is linked to the presence of partially oxidized and negatively charged surfaces, specifically those containing acid anhydride groups. Furthermore, proteins were found to control the bactericidal properties of nanodiamonds by covering these surface groups, which explains the previously reported biocompatibility of nanodiamonds. Our findings describe the discovery of an exciting property of partially oxidized nanodiamonds as a potent antibacterial agent.

  11. Bactericidal Antibiotics Increase Hydroxyphenyl Fluorescein Signal by Altering Cell Morphology

    DEFF Research Database (Denmark)

    Paulander, Wilhelm; Wang, Ying; Folkesson, Sven Anders;

    2014-01-01

    It was recently proposed that for bactericidal antibiotics a common killing mechanism contributes to lethality involving indirect stimulation of hydroxyl radical (OH center dot) formation. Flow cytometric detection of OH center dot by hydroxyphenyl fluorescein (HPF) probe oxidation was used...

  12. The bactericidal effect of a Genius (R) Nd : YAG laser

    NARCIS (Netherlands)

    Kranendonk, A.A.; Reijden, W.A. van der; Winkelhoff, A.J. van; Weijden, G.A. van der

    2010-01-01

    PURPOSE: To evaluate the 'in vitro' bactericidal effect of the Nd:YAG laser (Genius, MØlsgaard Dental, Copenhagen, Denmark) on six periodontal pathogens. METHODS: Suspensions of six different periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedi

  13. The bactericidal effect of a Genius Nd: YAG laser

    NARCIS (Netherlands)

    Kranendonk, A.A.; van der Reijden, W.A.; van Winkelhoff, A.J.; van der Weijden, G.A.

    2010-01-01

    Purpose: To evaluate the ‘in vitro’ bactericidal effect of the Nd:YAG laser (Genius, MØlsgaard Dental, Copenhagen, Denmark) on six periodontal pathogens. Methods: Suspensions of six different periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedi

  14. [Bactericidal activity of colloidal silver against grampositive and gramnegative bacteria].

    Science.gov (United States)

    Afonina, I A; Kraeva, L A; Tseneva, G Ia

    2010-01-01

    It was shown that colloidal silver solution prepared in cooperation with the A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, had significant bactericidal activity. Stable bactericidal effect on gramnegative microorganisms was observed after their 2-hour exposition in the solution of colloidal silver at a concentration of 10 ppm. Grampositive capsule-forming microorganisms were less susceptible to the colloidal silver solution: their death was observed after the 4-hour exposition in the solution.

  15. Physicochemical properties of bactericidal plasma-treated water

    Science.gov (United States)

    Ikawa, Satoshi; Tani, Atsushi; Nakashima, Yoichi; Kitano, Katsuhisa

    2016-10-01

    Plasma-treated water (PTW), i.e. distilled water (DW) exposed to low-temperature atmospheric pressure helium plasma, exhibited strong bactericidal activity against Escherichia coli in suspension even within a few minutes of preparation. This effect was enhanced under acidic conditions. The bactericidal activity of PTW was attenuated according to first-order kinetics and the half-life was highly temperature dependent. The electron spin resonance (ESR) signal of an adduct of the superoxide anion radical (\\text{O}2-\\bullet ) was detected in an aqueous solution using a spin-trapping reagent mixed with PTW, and adding superoxide dismutase to the PTW resulted in a loss of the bactericidal activity and weakening of the ESR adduct signal of \\text{O}2-\\bullet in the spin-trapping. These results suggest that \\text{O}2-\\bullet plays an important role in imparting bactericidal activity to PTW. Moreover, molecular nitrogen was required both in the ambient gas and in the DW used to prepare the PTW. We, therefore, suggest that the reactive molecule in PTW with bactericidal effects is not a free reactive oxygen species but nitrogen atom(s)-containing molecules that release \\text{O}2-\\bullet , such as peroxynitrous acid (ONOOH) or peroxynitric acid (O2NOOH). Considering the activation energy for degradation of these species, we conclude that peroxynitric acid stored in PTW induces the bactericidal effect.

  16. Two major medicinal honeys have different mechanisms of bactericidal activity.

    Directory of Open Access Journals (Sweden)

    Paulus H S Kwakman

    Full Text Available Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil® source (RS honey and manuka honey, the sources of two major medical-grade honeys. RS honey killed Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa within 2 hours, whereas manuka honey had such rapid activity only against B. subtilis. After 24 hours of incubation, both honeys killed all tested bacteria, including methicillin-resistant Staphylococcus aureus, but manuka honey retained activity up to higher dilutions than RS honey. Bee defensin-1 and H₂O₂ were the major factors involved in rapid bactericidal activity of RS honey. These factors were absent in manuka honey, but this honey contained 44-fold higher concentrations of methylglyoxal than RS honey. Methylglyoxal was a major bactericidal factor in manuka honey, but after neutralization of this compound manuka honey retained bactericidal activity due to several unknown factors. RS and manuka honey have highly distinct compositions of bactericidal factors, resulting in large differences in bactericidal activity.

  17. Two Major Medicinal Honeys Have Different Mechanisms of Bactericidal Activity

    NARCIS (Netherlands)

    Kwakman, P.H.S.; te Velde, A.A.; de Boer, L.; Vandenbroucke-Grauls, C.M.J.E.; Zaat, S.A.J.

    2011-01-01

    Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil (R) source (RS) honey and manuka honey, the sources of two major medical-grade honeys. RS honey k

  18. Mutacin II, a Bactericidal Lantibiotic from Streptococcus mutans

    NARCIS (Netherlands)

    Chikindas, Michael L.; Novák, Jan; Driessen, Arnold J.M.; Konings, Wilhelmus; Schilling, Kurt M.; Caufield, Page W.

    1995-01-01

    Mutacin II is a lantibiotic that is produced by group II Streptococcus mutans, it inhibits the growth of other streptococci as well as many other gram-positive microorganisms by a hitherto unknown mechanism, Mutacin LI possesses bactericidal activity against susceptible cells. It transiently depolar

  19. Studies on bactericidal efficacy of pumpkin (Cucurbita moschata Duchesne) peel

    Institute of Scientific and Technical Information of China (English)

    El Zawane Kamarudin; Qamar Uddin Ahmed; Zuvairea Nazren Mohd Sirajudin; Ahmad Jalal Khan Chowdhury

    2014-01-01

    Objective: To explore the in vitro antibacterial potential of the peel of Cucurbita moschata Duchesne (tropical pumpkin) (C. moschata) against human pathogenic bacteria. Methods:In the present study, dichloromethane (DCM), methanol (MEOH) and aqueous extracts of C. moschata peel were examined for in vitro antibacterial potency against eight bacterial strains i.e. Bacillus cereus, Burkholderia cepacia, Escherichia coli, Enterococcus faecalis, Staphyloccocus aureus, Pseudomonas aerugenosa, Vibrio alginolyticus, Vibrio parahaemolyticus using Kirby-Bauer disk diffusion susceptibility and broth micro-dilution methods. Results: DCM extract of pumpkin peel exhibited the maximum zone of inhibition against Staphyloccocus aureus (21 mm) whereas aqueous extract of pumpkin peel revealed the least zone of inhibition against Escherichia coli (8 mm). MEOH extract gave maximum zone of inhibition against Pseudomonas aerugenosa (19 mm). Broth micro-dilution method showed minimum inhibitory concentration for the DCM extract against Burkholderia cepacia at 6.25 mg/mL. The minimum bactericidal concentrations were also determined to know the nature of all extracts. DCM and MEOH extracts exhibited bactericidal nature to all bacterial strains except for the Vibrio alginolyticus. The minimum bactericidal concentrations values exhibited bactericidal nature ranging from 3.12 mg/mL to 100.00 mg/mL. The screening of antimicrobial properties of different extracts of C. moschata peel revealed that the DCM extract possessed good antimicrobial efficacy compared to MEOH and aqueous extracts. Conclusions: Peel of C. moschata possesses antibacterial compounds and could be potential source for a new class of antibiotics.

  20. Bactericidal activity of glutaraldehyde-like compounds from olive products.

    Science.gov (United States)

    Medina, Eduardo; Brenes, Manuel; García, Aranzazu; Romero, Concepción; de Castro, Antonio

    2009-12-01

    The bactericidal effects of several olive compounds (nonenal, oleuropein, tyrosol, the dialdehydic form of decarboxymethyl elenolic acid either free [EDA] or linked to tyrosol [TyEDA] or to hydroxytyrosol [HyEDA]), other food phenolic compounds (catechin, epicatechin, eugenol, thymol, carvacrol, and carnosic acid), and commercial disinfectants (glutaraldehyde [GTA] and ortho-phthalaldehyde [OPA]), were tested against strains of Pseudomonas fluorescens, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli. It was found that the bactericidal activities of olive GTA-like compounds (EDA, HyEDA, and TyEDA) were greater than those exerted by several food phenolic substances. Surprisingly, these olive antimicrobials were as active as the synthetic biocides GTA and OPA against the four bacteria studied. Thus, it has been proposed that the bactericidal activity of the main olive antimicrobials is primarily due to their dialdehydic structure, which is similar to that of the commercial biocides GTA and OPA. Our results clearly reveal that olive GTA-like compounds possess a strong bactericidal activity even greater than that of other food phenolic compounds or synthetic biocides.

  1. Studies on bactericidal efficacy of pumpkin (Cucurbita moschata Duchesne peel

    Directory of Open Access Journals (Sweden)

    El Zawane Kamarudin

    2014-02-01

    Full Text Available Objective: T o explore the in vitro antibacterial potential of the peel of Cucurbita moschata D uchesne ( tropical pumpkin ( C. moschata against human pathogenic bacteria. Methods: I n the present study, dichloromethane ( DCM , methanol ( MEOH and aqueous extracts of C. moschata peel were examined for in vitro antibacterial potency against eight bacterial strains i.e. Bacillus cereus, Burkholderia cepacia, Escherichia coli, Enterococcus faecalis, Staphyloccocus aureus, Pseudomonas aerugenosa, Vibrio alginolyticus, Vibrio parahaemolyticus using K irby- B auer disk diffusion susceptibility and broth micro-dilution methods. Results: DCM extract of pumpkin peel exhibited the maximum zone of inhibition against Staphyloccocus aureus ( 21 mm whereas aqueous extract of pumpkin peel revealed the least zone of inhibition against Escherichia coli ( 8 mm . MEOH extract gave maximum zone of inhibition against Pseudomonas aerugenosa ( 19 mm . B roth micro-dilution method showed minimum inhibitory concentration for the DCM extract against Burkholderia cepacia at 6 . 25 mg/m L . T he minimum bactericidal concentrations were also determined to know the nature of all extracts. DCM and MEOH extracts exhibited bactericidal nature to all bacterial strains except for the Vibrio alginolyticus. T he minimum bactericidal concentrations values exhibited bactericidal nature ranging from 3 . 12 mg/m L to 100 . 00 mg/m L . T he screening of antimicrobial properties of different extracts of C. moschata peel revealed that the DCM extract possessed good antimicrobial efficacy compared to MEOH and aqueous extracts. Conclusions: P eel of C. moschata possesses antibacterial compounds and could be potential source for a new class of antibiotics.

  2. TLR signaling augments macrophage bactericidal activity through mitochondrial ROS

    OpenAIRE

    West, A. Phillip; Brodsky, Igor E.; Rahner, Christoph; Woo, Dong Kyun; Erdjument-Bromage, Hediye; Tempst, Paul; Walsh, Matthew C; Choi, Yongwon; Shadel, Gerald S.; Ghosh, Sankar

    2011-01-01

    Reactive oxygen species (ROS) are essential components of the innate immune response against intracellular bacteria, and it is thought that professional phagocytes generate ROS primarily via the phagosomal NADPH oxidase (Phox) machinery 1 . However, recent studies have suggested that mitochondrial ROS (mROS) also contribute to macrophage bactericidal activity, although the mechanisms linking innate immune signaling to mitochondria for mROS generation remain unclear 2-4 . Here we demonstrate t...

  3. Bactericidal activity of titanium dioxide ultraviolet-induced films

    Energy Technology Data Exchange (ETDEWEB)

    Pleskova, S.N., E-mail: pleskova@mail.ru [Laboratory of Biochemistry and Molecular Biology, Tomsk State University, ave. Lenina 36, Tomsk 634050 (Russian Federation); Golubeva, I.S., E-mail: golubmay@mail.ru [Institute of applied biotechnology of Nizhny Novgorod, Yablonevaya Street 22, Nizhny Novgorod 603093 (Russian Federation); Verevkin, Y.K., E-mail: verevkin@appl.sci-nnov.ru [Institute of applied physics of the Russian Academy of Science, Ul' yanov Street, 46, Nizhny Novgorod 603950 (Russian Federation)

    2016-02-01

    TiO{sub 2} films are used as a self-sterilization surface due to their property to form reactive oxygen species (ROS) when irradiated with ultraviolet light. These ROS attack bacteria and kill them. We present a new way to enhance the bactericidal activity of TiO{sub 2}-films: formation of nanopores on the surface by four-beam high-power laser irradiation. Such surfaces have significantly higher antibacterial activity as compared to conventional TiO{sub 2} surfaces after 15 and 60 min of UV irradiation. Study of the bacterial cell morphology by atomic force microscopy after 60 min irradiation showed that Staphylococcus aureus 956 and Escherichia coli 321–5 undergo significant morphological changes. S. aureus assume atypical elongated shapes after UV treatment alone and swollen forms with protrusions after UV treatment on TiO{sub 2} surface. E. coli exhibit oval or round forms after UV treatment alone, and round forms with small protrusions, and destroyed cells after incubation under UV on the TiO{sub 2} film. - Highlights: • Nanopores on the TiO{sub 2} surface enhance the bactericidal activity of films. • The bactericidal effect of TiO{sub 2} is strain-specific. • The bacterial morphology significantly changes after UV/TiO{sub 2} treatment.

  4. Bactericidal and cytotoxic effects of Erythrina fusca leaves aquadest extract

    Directory of Open Access Journals (Sweden)

    Janti Sudiono

    2013-03-01

    Full Text Available Background: Empirically, Erythrina fusca has been used as traditional herb for its antibacterial and antiinflammation properties. Periodontal disease is one of the most oral infectious diseases with microorganism predominated as the contributing factors. Porphyromonas gingivalis (P. gingivalis is one of the main bacteria pathogen found in periodontal diseases. Purpose: The purpose of this study was to examine the bactericidal effect of Erythrina fusca Leaves Aquadest Extract (EFLAE at various concentrations on P. gingivalis and cytotoxic effect on fibroblast. Methods: Pure P. gingivalis was cultured in Brain Heart Infusion (BHI medium for 24 hours with or without various concentrations of treatment of EFLAE. Calculation and statistical analysis of remaining bacteria were performed by inhibitory zone method to evaluate the EFLAE bactericidal effect and compared to chlorhexidine as positive control. To evaluate the cytotoxic effect, NIH 3T3 cells were cultured in Dulbecco’s Modification of Eagle’s Medium (DMEM containing of 10% fetal bovine serum (FBS and 1% penicillin-streptomycin, pH 7.2, in 5% CO2, and stored in humidified incubator under temperature 370 C. Cells were treated with/without various concentrations of EFLAE for 48 hours. The viable cells were then counted using 3-(4,5- Dimethylthiazol-2-yl-2,5 diphenyl tetrazodium bromide (MTT method. Results: EFLAE have bactericidal effect on P. gingivalis in a concentration dependent manner starting from 78%. The concentration of 90% EFLAE had stronger bactericidal effect (35.004 ± 1.546 than those of chlorhexidine as positive control (32.313 ± 1.619. One-way ANOVA showed significant bactericidal effect differences among concentrations of EFLAE and chlorhexidine (p<0.05 while Tuckey HSD test showed significant difference only between lower concentration of EFLAE (78%, 79% and chlorhexidine. With the highest concentration of EFLAE (100% applied in the bactericidal test, no cytotoxic effect

  5. [Bactericidal activity of serum and chemotherapy in sensitive and resistant exciter (author's transl)].

    Science.gov (United States)

    Eyer, H; Metz, H; Preac-Mursic, V

    1975-11-21

    Comparing examinations with Ampicillin sensitive and resistant bacteria-strains show that the bactericidal activity of serum is dependent on the bacteria-strains, on the Ampicillin sensitivity of the particular exciter and on the number of bacteria/ml (germ count). Bactericide effect could always be obtained with sensitive strains as a result of additional chemotherapy. With several resistant strains a bactericide effect could not be obtained in this case the continuous optimal Ampicillin addition was the decisive factor. Because of the extremely complicated process of the bactericide one should not make general conclusions from the individual experimental results.

  6. Bactericidal Efficacy of Sanitizers Produced by Commercial Water Treatment Generators

    Science.gov (United States)

    2009-04-01

    volumes of a 1: lOTSYEB dilution ofeach strain in a single test tube. Sterile Tween 80 (0.1 ml of a 1% solution) was added to 8-10 ml of culture and mixed...served as a tween - 80 positive count (no kill) controls, and two coupons served as the untreated numbers control. An additional coupon inoculated with... Tween 80 , a non-reactive reagent with no bactericidal activity. 2.3.4 Numbers Control. To determine the number of recoverable bacteria, two coupons

  7. Bactericidal activity of Pistacia lentiscus mastic gum against Helicobacter pylori.

    Science.gov (United States)

    Marone, P; Bono, L; Leone, E; Bona, S; Carretto, E; Perversi, L

    2001-12-01

    In this study we evaluated the antibacterial activity of mastic gum, a resin obtained from the Pistacia lentiscus tree, against clinical isolates of Helicobacter pylori. The minimal bactericidal concentrations (MBCs) were obtained by a microdilution assay. Mastic gum killed 50% of the strains tested at a concentration of 125 microg/ml and 90% at a concentration of 500 microg/ml. The influence of sub-MBCs of mastic gum on the morphologies of H. pylori was evaluated by transmission electron microscopy. The lentiscus resin induced blebbing, morphological abnormalities and cellular fragmentation in H. pylori cells.

  8. Crosstalk between circadian rhythmicity, mitochondrial dynamics and macrophage bactericidal activity

    Science.gov (United States)

    Oliva-Ramírez, Jacqueline; Moreno-Altamirano, María Maximina B; Pineda-Olvera, Benjamín; Cauich-Sánchez, Patricia; Sánchez-García, F Javier

    2014-01-01

    Biological functions show rhythmic fluctuations with 24-hr periodicity regulated by circadian proteins encoded by the so-called ‘clock’ genes. The absence or deregulation of circadian proteins in mice leads to metabolic disorders and in vitro models have shown that the synthesis of pro-inflammatory cytokines by macrophages follows a circadian rhythm so showing a link between circadian rhythmicity, metabolism and immunity. Recent evidence reveals that mitochondrial shape, position and size, collectively referred to as mitochondrial dynamics, are related to both cell metabolism and immune function. However, studies addressing the simultaneous crosstalk between circadian rhythm, mitochondrial dynamics and cell immune function are scarce. Here, by using an in vitro model of synchronized murine peritoneal macrophages, we present evidence that the mitochondrial dynamics and the mitochondrial membrane potential (Δψm) follow a circadian rhythmic pattern. In addition, it is shown that the fusion of mitochondria along with high Δψm, indicative of high mitochondrial activity, precede the highest phagocytic and bactericidal activity of macrophages on Salmonella typhimurium. Taken together, our results suggest a timely coordination between circadian rhythmicity, mitochondrial dynamics, and the bactericidal capacity of macrophages. PMID:24903615

  9. Bactericidal behavior of Cu-containing stainless steel surfaces

    Science.gov (United States)

    Zhang, Xiangyu; Huang, Xiaobo; Ma, Yong; Lin, Naiming; Fan, Ailan; Tang, Bin

    2012-10-01

    Stainless steels are one of the most common materials used in health care environments. However, the lack of antibacterial advantage has limited their use in practical application. In this paper, antibacterial stainless steel surfaces with different Cu contents have been prepared by plasma surface alloying technology (PSAT). The steel surface with Cu content 90 wt.% (Cu-SS) exhibits strong bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 3 h. Although the Cu-containing surface with Cu content 2.5 wt.% (CuNi-SS) can also kill all tested bacteria, this process needs 12 h. SEM observation of the bacterial morphology and an agarose gel electrophoresis were performed to study the antibacterial mechanism of Cu-containing stainless steel surfaces against E. coli. The results indicated that Cu ions are released when the Cu-containing surfaces are in contact with bacterial and disrupt the cell membranes, killing the bacteria. The toxicity of Cu-alloyed surfaces does not cause damage to the bacterial DNA. These results provide a scientific explanation for the antimicrobial applications of Cu-containing stainless steel. The surfaces with different antibacterial abilities could be used as hygienic surfaces in healthcare-associated settings according to the diverse requirement of bactericidal activities.

  10. Serum Bactericidal Assay: New Role in Salmonella Detection.

    Science.gov (United States)

    Chen, Yu; Wu, Da; Sun, Min; Deng, Mingjun; Cui, Shuhua; Liang, Chengzhu; Geng, Juan; Sun, Tao; Long, Ling; Xiao, Xizhi

    2016-01-01

    While inspecting animal feed for Salmonella contamination, we routinely observed bacterial colonies on selective agars that were similar in appearance to those formed by Salmonella. These were identified as Citrobacter freundii, Proteus mirabilis, and Serratia fonticola using biochemical and serological techniques. Because the presence of these bacterial species confounds identification of Salmonella, we refer to them as "interference bacteria." Polyvalent antisera against these interference bacteria were prepared by immunizing rabbits with a mixture of all three organisms. To minimize or eliminate interference by these bacteria, the polyvalent antisera were introduced between the steps of selective enrichment and Salmonella-selective plating. The antisera raised against the interference bacteria, when combined with neonatal rabbit complement, exhibited specific bactericidal activity against C. freundii, P. mirabilis, and S. fonticola. The respective serum bactericidal assay titers were 2(9), 2(8), and 2(10). In selective broth, polyvalent antisera could also kill the target bacterial cells effectively. We tested 526 samples (186 white fishmeal, 97 red fishmeal, and 243 cattle bone powder) using the polyvalent antisera and found that the rates of contamination of each species of the three respective foods decreased by 58.8, 100, and 83%. Our data indicates that polyvalent sera against C. freundii, P. mirabilis, and S. fonticola can be used as inhibitors to increase the accuracy of Salmonella detection.

  11. Phosphorylcholine allows for evasion of bactericidal antibody by Haemophilus influenzae.

    Directory of Open Access Journals (Sweden)

    Sarah E Clark

    Full Text Available The human pathogen Haemophilus influenzae has the ability to quickly adapt to different host environments through phase variation of multiple structures on its lipooligosaccharide (LPS, including phosphorylcholine (ChoP. During colonization with H. influenzae, there is a selection for ChoP+ phase variants. In a murine model of nasopharyngeal colonization, this selection is lost in the absence of adaptive immunity. Based on previous data highlighting the importance of natural antibody in limiting H. influenzae colonization, the effect of ChoP expression on antibody binding and its bactericidal activity was investigated. Flow cytometric analysis revealed that ChoP+ phase variants had decreased binding of antibody to LPS epitopes compared to ChoP- phase variants. This difference in antibody binding correlated with increased survival of ChoP+ phase variants in the presence of antibody-dependent, complement-mediated killing. ChoP+ phase variants were also more resistant to trypsin digestion, suggesting a general effect on the physical properties of the outer membrane. Moreover, ChoP-mediated protection against antibody binding correlated with increased resilience of outer membrane integrity. Collectively, these data suggest that ChoP expression provides a selective advantage during colonization through ChoP-mediated effects on the accessibility of bactericidal antibody to the cell surface.

  12. Bactericidal antibody response to Pseudomonas aeruginosa by adults with urinary tract infections.

    Science.gov (United States)

    Smalley, D L; Ourth, D D

    1979-01-01

    In this investigation we found that adults with upper urinary tract infections caused by Pseudomonas aeruginosa produced serum antibodies with bactericidal activity against the bacterium. Seventeen of 20 infected adults showed bactericidal activity with a titer range of 1:10 to 1:10,000. PMID:117024

  13. Bactericidal Antibiotics Do Not Appear To Cause Oxidative Stress in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Feld, Louise; Knudsen, Gitte Maegaard; Gram, Lone

    2012-01-01

    self-destruction by internal production of hydroxyl radicals. The purpose of the present study was to determine if a similar mechanism is involved in antibiotic killing of the infectious human pathogen, Listeria monocytogenes. We treated wild-type L. monocytogenes and oxidative stress mutants (Δsod......Oxidative stress can be an important contributor to the lethal effect of bactericidal antibiotics in some bacteria, such as Escherichia coli and Staphylococcus aureus. Thus, despite the different target-specific actions of bactericidal antibiotics, they have a common mechanism leading to bacterial...... and Δfri) with three different bactericidal antibiotics and found no difference in killing kinetics. In contrast, wild-type E. coli and an oxidative stress mutant (ΔsodA ΔsodB) differed significantly in their sensitivity to bactericidal antibiotics. We conclude that bactericidal antibiotics did not appear...

  14. Bactericidal Influence of Silver Nanocomposites on Clavibacter michiganensis ssp. sepedonicus

    Directory of Open Access Journals (Sweden)

    Perfileva А.I.

    2016-05-01

    Full Text Available The results of studying the effect of silver nanocomposites received by chemical synthesis on the bacterium Clavibacter michiganensis ssp. sepedonicus (Cms are presented. Cms is a Gram-positive bacterium, which causes one of the most dangerous potato diseases, ring rot. The effective alongside ecologically safe methods for combating Cms are lacking. As the agent, possible for application for this purpose, we investigated silver nanocomposites. For definition of nanocomposites influence on Cms we applied seedings to calculation the colony-forming units, after an incubation of bacteria with a nanocomposite in the distilled water (the grown poor environment and on a nutrient medium. Influence of silver nanocomposites on cellular respiration which was estimated on oxygen absorption speed is also investigated. Thus, the obtained results demonstrate the occurrence of bactericidal effects of the substances under study, and favor the supposition on advisability of further research into the silver nanocomposites as the agents for agricultural recovery from the bacterial pathogens.

  15. Bactericidal Antibiotics Increase Hydroxyphenyl Fluorescein Signal by Altering Cell Morphology

    DEFF Research Database (Denmark)

    Paulander, Wilhelm; Wang, Ying; Folkesson, Sven Anders;

    2014-01-01

    It was recently proposed that for bactericidal antibiotics a common killing mechanism contributes to lethality involving indirect stimulation of hydroxyl radical (OH center dot) formation. Flow cytometric detection of OH center dot by hydroxyphenyl fluorescein (HPF) probe oxidation was used...... to support this hypothesis. Here we show that increased HPF signals in antibiotics-exposed bacterial cells are explained by fluorescence associated with increased cell size, and do not reflect reactive oxygen species (ROS) concentration. Independently of antibiotics, increased fluorescence was seen...... for elongated cells expressing the oxidative insensitive green fluorescent protein (GFP). Although our data question the role of ROS in lethality of antibiotics other research approaches point to important interplays between basic bacterial metabolism and antibiotic susceptibility. To underpin...

  16. Bactericidal antibiotics increase hydroxyphenyl fluorescein signal by altering cell morphology.

    Directory of Open Access Journals (Sweden)

    Wilhelm Paulander

    Full Text Available It was recently proposed that for bactericidal antibiotics a common killing mechanism contributes to lethality involving indirect stimulation of hydroxyl radical (OH• formation. Flow cytometric detection of OH• by hydroxyphenyl fluorescein (HPF probe oxidation was used to support this hypothesis. Here we show that increased HPF signals in antibiotics-exposed bacterial cells are explained by fluorescence associated with increased cell size, and do not reflect reactive oxygen species (ROS concentration. Independently of antibiotics, increased fluorescence was seen for elongated cells expressing the oxidative insensitive green fluorescent protein (GFP. Although our data question the role of ROS in lethality of antibiotics other research approaches point to important interplays between basic bacterial metabolism and antibiotic susceptibility. To underpin such relationships, methods for detecting bacterial metabolites at a cellular level are needed.

  17. Synergistic bactericidal interaction of josamycin with human neutrophils in vitro.

    Science.gov (United States)

    Labro, M T; el Benna, J

    1990-10-01

    Josamycin and erythromycin have been compared for their in-vitro interaction with bactericidal killing by human neutrophils. The mechanism of this interaction was studied in two ways. First, the target organisms (Staphylococcus aureus and Pseudomonas aeruginosa) were incubated for 60 min with josamycin, erythromycin or control buffer prior to use in a human polymorphonuclear neutrophil (PMN) killing assay. Second the macrolides were added directly to acellular killing systems mimicking those acting inside the phagolysosome; oxygen-independent systems were obtained from a crude granule extract of PMN and oxygen-dependent systems consisted either of a mixture of xanthine plus xanthine oxidase or of a solution of H2O2. Whereas josamycin-pretreated P. aeruginosa were twice as sensitive to killing by PMN than were control cells, this was not the case for S. aureus. Both oxidant generating systems were more effective in destroying S. aureus in the presence of josamycin (3 and 30 mg/l). Erythromycin showed a similar synergy but only with the xanthine plus xanthine oxidase system. This synergy was observed with neither of the O2-independent systems for S. aureus, nor with any acellular system for P. aeruginosa. These data suggest that at least two kinds of mechanism may explain the bactericidal synergy observed between macrolides and PMN. The first (for macrolide-resistant species such as P. aeruginosa) could be due to alterations in the bacteria by the antibiotics, while the second (for macrolide-sensitive species such as S. aureus) could be based upon an as yet unexplained transformation of the molecules by reactive oxygen species into more "toxic" forms. These differences between josamycin and erythromycin could arise from differences in their chemical structure.

  18. Characterization and activity of an immobilized antimicrobial peptide containing bactericidal PEG-hydrogel.

    Science.gov (United States)

    Cleophas, Rik T C; Sjollema, Jelmer; Busscher, Henk J; Kruijtzer, John A W; Liskamp, Rob M J

    2014-09-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein staining agents as well as by X-ray photoelectron spectroscopy. The bactericidal activity was established against Staphylococcus aureus and Staphylococcus epidermidis, two bacterial strains commonly associated with biomaterial infections. To gain further insight into the biological stability, the hydrogels were incubated with human serum prior to activity testing without loss of activity. These studies revealed a promising bactericidal hydrogel with good stability under physiological conditions.

  19. Treatment and prevention of Staphylococcus epidermidis experimental biomaterial-associated infection by bactericidal peptide 2

    NARCIS (Netherlands)

    P.H.S. Kwakman; A.A.T. Velde; C.M.J.E. Vandenbroucke-Grauls; S.J.H. van Deventer; S.A.J. Zaat

    2006-01-01

    Biomaterial-associated infections (BAI) are the major cause of failure of indwelling medical devices and are predominantly caused by staphylococci, especially Staphylococcus epidermidis. We investigated the in vitro microbicidal activity of the synthetic antimicrobial peptide bactericidal peptide 2

  20. Serum bactericidal activity as indicator of innate immunity in pacu Piaractus mesopotamicus (Holmberg, 1887

    Directory of Open Access Journals (Sweden)

    J.D. Biller-Takahashi

    2013-12-01

    Full Text Available The immune system of teleost fish has mechanisms responsible for the defense against bacteria through protective proteins in several tissues. The protein action can be evaluated by serum bactericidal activity and this is an important tool to analyze the immune system. Pacu, Piaractus mesopotamicus, is one of the most important fish in national aquaculture. However there is a lack of studies on its immune responses. In order to standardize and assess the accuracy of the serum bactericidal activity assay, fish were briefly challenged with Aeromonas hydrophila and sampled one week after the challenge. The bacterial infection increased the concentration of protective proteins, resulting in a decrease of colony-forming unit values expressed as well as an enhanced serum bactericidal activity. The protocol showed a reliable assay, appropriate to determine the serum bactericidal activity of pacu in the present experimental conditions.

  1. Bactericidal effect of Nd:YAG laser irradiation in endodontics

    Science.gov (United States)

    Aun, Carlos E.; Barberini, Alexandre F.; Camargo, Selma C. C.; Silva Kfouri, Luciana; Lorenzetti Simionato, Maria R.

    1999-05-01

    The success of endodontic therapy is based on the elimination of bacterial colonization from the endodontic system and periapical tissues. Recent studies have been showing the bactericidal effect of laser in root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canals from upper central incisor. For the experiment 12 teeth were selected, respect at the apical third, sterilized, and 10 μm Streptococcus sanguis liquid culture were inoculated in the root canals. The laser test groups were irradiated with Nd:YAG laser at standard setting of 15Hz, 100mj and 1,5 W for 10, 20 and 30 seconds each in slow helicoidal movements from the apex to the top using a 300 micrometers fiber. After the procedure the specimens were placed in Tryptic Soy Agar, the number of colony forming units was evaluated. The experiment showed a significant reduction on viability of Streptococcus sanguis at the respective time of 20 and 30 seconds.

  2. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Alvarez, S. A. [UASLP, Doctorado Institucional en Ingenieria y Ciencia de Materiales (Mexico); Martinez-Castanon, G. A., E-mail: mtzcastanon@fciencias.uaslp.m [UASLP, Maestria en Ciencias Odontologicas, Facultad de Estomatologia (Mexico); Nino-Martinez, N. [UASLP, Facultad de Ciencias (Mexico); Reyes-Macias, J. F.; Patino-Marin, N.; Loyola-Rodriguez, J. P. [UASLP, Maestria en Ciencias Odontologicas, Facultad de Estomatologia (Mexico); Ruiz, Facundo [UASLP, Facultad de Ciencias (Mexico)

    2010-10-15

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 {mu}g/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  3. The Application of Bactericidal Silver Nanoparticles in Wound Treatment

    Directory of Open Access Journals (Sweden)

    Geewoo Nam

    2015-07-01

    Full Text Available Even with the prevalence of wounds, the medical technol‐ ogy for efficiently managing skin damage is still primitive. The disruption of any of the numerous healing processes can lead to problems in the time-sensitive healing actions of the dermal and epidermal layers. Bacterial infection is one of the major obstacles to proper wound healing as it poses a danger of causing long-term negative effects. Keeping the wound free of bacteria is imperative to the proper and hasty repair of dermal wounds. Silver has been widely used to treat wounds for its bactericidal properties. Although the mechanism of silver’s antibacterial action is not fully understood, it exhibits a significant antimicrobial efficacy against a wide spectrum of bacterial species. A number of different approaches to the mechanism are reported and presented in this review. Silver nanoparticles (AgNPs have been reported to exhibit enhanced antibac‐ terial activity due to their increased surface-area-to-volume ratio. AgNPs are capable of various modifications, signifi‐ cantly broadening the therapeutic properties of the mate‐ rial as a result. This review explores the different aspects of silver and silver nanoparticles, and their antibacterial properties, which can be applied in the field of wound treatments.

  4. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    Science.gov (United States)

    Moreno-Álvarez, S. A.; Martínez-Castañón, G. A.; Niño-Martínez, N.; Reyes-Macías, J. F.; Patiño-Marín, N.; Loyola-Rodríguez, J. P.; Ruiz, Facundo

    2010-10-01

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 μg/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  5. [Bactericidal activity of sitafloxacin and other new quinolones against antimicrobial resistant Streptococcus pneumoniae].

    Science.gov (United States)

    Kobayashi, Intetsu; Kanayama, Akiko; Hasegawa, Miyuki; Kaneko, Akihiro

    2013-02-01

    We conducted a study assess the bactericidal activity of sitafloxacin (STFX) against Streptococcus pneumoniae isolates recovered from respiratory infections including penicillin-resistant (PRSP) isolates, macrolide resistant isolates possessing mefA and ermB resistance genes and quinolone resistance isolates with mutations in gyrA or gyrA and parC. Each isolate tested was grown in hemosupplemented Mueller-Hinton broth and adjusted to approximately 10(5) CFU/ mL. Isolates were than exposed to a Cmax antimicrobial blood level that would be attained with routine antimicrobial administration and an antimicrobial level that would be expected 4 hours post-Cmax (Cmax 4hr). Bactericidal activity was measured for up to 8 hours. Excluding a subset of S. pneumoniae isolates with mutations in the quinolone resistance determining region (QRDR), all quinolones showed bactericidal activity at Cmax and Cmax 4 hr antimicrobial concentrations for up to 8 hours. Against S. pneumoniae isolates with either gyrA or gyrA and parC mutations, bactericidal activity of STFX was shown for up to 4 to 8 hours following Cmax based on a limit of detection of quinolones tested where adjusted to concentrations corresponding to their MICs, STFX showed the most rapid bactericidal activity against PRSP. This rapid bactericidal activity in PRSP is a key to the effectiveness of STFX. Our findings show that beyond inhibition of bacterial replication by blocking their DNA replication pathway and synthesis of proteins, STFX demonstrated characteristics contributing to greater bactericidal activity compared to GRNX. In conclusion, of the newer quinolones, STFX showed the strongest bactericidal activity against S. pneumoniae isolates with mutations in the QRDR which indicates that it may show the most effective clinical utility among the quinolones in respiratory infections.

  6. Fungi and bacteria. [fungicide and bactericide measures for spacecraft in tropical regions

    Science.gov (United States)

    Daniels, G. E.

    1973-01-01

    Spacecraft equipment is usually protected from fungi and bacteria by incorporating a fungicide-bactericide in the material, by a fungicide-bactericide spray, or by reducing the relative humidity to a degree where growth will not take place. A unique method to protect delicate, expensive bearings in equipment was to maintain a pressure (with dry air or nitrogen) slightly above the outside atmosphere (few millibars) within the working parts of the equipment, thus preventing fungi from entering equipment.

  7. Bactericidal Effects of Natural Nanotopography of Dragonfly Wing on Escherichia coli.

    Science.gov (United States)

    Bandara, Chaturanga D; Singh, Sanjleena; Afara, Isaac O; Wolff, Annalena; Tesfamichael, Tuquabo; Ostrikov, Kostya; Oloyede, Adekunle

    2017-03-01

    Nanotextured surfaces (NTSs) are critical to organisms as self-adaptation and survival tools. These NTSs have been actively mimicked in the process of developing bactericidal surfaces for diverse biomedical and hygiene applications. To design and fabricate bactericidal topographies effectively for various applications, understanding the bactericidal mechanism of NTS in nature is essential. The current mechanistic explanations on natural bactericidal activity of nanopillars have not utilized recent advances in microscopy to study the natural interaction. This research reveals the natural bactericidal interaction between E. coli and a dragonfly wing's (Orthetrum villosovittatum) NTS using advanced microscopy techniques and proposes a model. Contrary to the existing mechanistic models, this experimental approach demonstrated that the NTS of Orthetrum villosovittatum dragonfly wings has two prominent nanopillar populations and the resolved interface shows membrane damage occurred without direct contact of the bacterial cell membrane with the nanopillars. We propose that the bacterial membrane damage is initiated by a combination of strong adhesion between nanopillars and bacterium EPS layer as well as shear force when immobilized bacterium attempts to move on the NTS. These findings could help guide the design of novel biomimetic nanomaterials by maximizing the synergies between biochemical and mechanical bactericidal effects.

  8. Time-resolved fluoroimmunoassay for bactericidal/permeability-increasing protein

    Directory of Open Access Journals (Sweden)

    J.-O. Häggblom

    1996-01-01

    Full Text Available Bactericidal/permeability-increasing protein (BPI is a cationic antimicrobial protein produced by polymorphonuclear leukocytes, that specifically interacts with and kills Gram-negative bacteria. BPl competes with lipopolysaccharide-binding protein (LBP secreted by liver cells into blood plasma for binding to lipopolysaccharide (LPS and thus reduces the proinflammatory effects of LPS. We have developed a time-resolved fluoroimmunoassay for BPI and measured the concentration of BPI in human serum and plasma samples. The assay is based on a rabbit antibody against recombinant BPI. This antibody specifically adheres to polymorphonuclear leukocytes in immunostained human tissues. The difference in the serum concentration of BPI between unselected hospitalized patients with and without an infection was statistically significant. The mean concentration of BPI in serum samples was 28.3 μg/l (range 1.64–132, S.D. 26.8, n = 83. In contrast, there was no difference between the two groups in the BPI levels in plasma samples. For all individuals tested, BPI levels were consistently higher in plasma samples compared to the matched serum samples. The mean concentration of BPI in plasma samples was 52.3 μg/l (range 0.9–403, S.D. 60.6, n = 90. There was a positive correlation between the concentration of BPI and the white blood cell count as well as between the BPI concentration and C-reactive protein (CRP in serum samples. In conclusion, the present study demonstrates that BPI can be quantified reliably by time-resolved fluoroimmunoassay in human serum samples.

  9. Bactericidal Mechanisms of Ag2O/TNBs under both Dark and Light Conditions

    Science.gov (United States)

    Jin, Yinjia; Dai, Zhaoyi; Liu, Fei; Kim, Hyunjung; Tong, Meiping; Hou, Yanglong

    2013-04-01

    Ag2O deposited titanium dioxides nanobelts (Ag2O/TNBs) were fabricated and used to investigate the toxic effects on aquatic microorganisms. The disinfection activities of Ag2O/TNBs on two representative bacterial strains: Gram-negative E. coli and Gram-positive B. subtilis, were examined under both dark and light conditions. Ag2O/TNBs exhibited stronger bactericidal activities than TNBs under both dark and light conditions. For both cell types, disinfection effects of Ag2O/TNBs were greater under light conditions relative to those under dark conditions. The bactericidal mechanisms of Ag2O/TNBs under both dark and light conditions were explored. Under dark conditions, neither Ag+ ions released from Ag2O/TNBs nor TNBs contributed to the bactericidal activities of Ag2O/TNBs. Under light conditions, both the released Ag+ions and TNBs yet were found to have contributions to the bactericidal effects of Ag2O/TNBs. Active species (H2O2, ?O2-, ande-) generated by Ag2O/TNBs played important roles in the disinfection processes under both dark and light conditions. Without the presence of active species, the direct contact of Ag2O/TNBs with bacterial cells had no bactericidal effect.

  10. Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori

    Institute of Scientific and Technical Information of China (English)

    Rachel O'Mahony; Huda Al-Khtheeri; Deepeka Weerasekera; Neluka Fernando; Dino Vaira; John Holton; Christelle Basset

    2005-01-01

    AIM: To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H pylori).METHODS: Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H pylori to stomach sections. RESULTS: Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric; borage and parsley were able to inhibit the adhesion of H pylori strains to the stomach sections.CONCLUSION: Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.

  11. The behavior of active bactericidal and antifungal coating under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Gang; Zhang, Xiaodong; Zhao, Yan; Su, Haijia, E-mail: suhj@mail.buct.edu.cn; Tan, Tianwei

    2014-02-15

    In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO{sub 2} (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO{sub 2} is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO{sub 2}. The contact angle measurement demonstrated the hydrophilicity of ABAC (θ = 34.5 ± 4.1°). The bactericidal activity of ABAC has been evaluated by inactivating three different test strains: Escherichia coli, Candida albicans and Aspergillus niger which illustrates the apparently higher bactericidal ability than chitosan, Fe-TiO{sub 2} and chitosan/TiO{sub 2} (pure) under visible light irradiation and its bactericidal activity is lasting for at least 24 h. ABAC showed rapid and efficient antibacterial ability for the three tested strains and its antibacterial ratio in 2 h for E. coli, C. albicans and A. niger was 99.9%, 97.0% and 95.0%, respectively. The prepared chitosan/TiO{sub 2} composite emulsion shows favorable storage stability and can be stored up to 1 year without losing its bactericidal activity. ABAC is a low-cost and eco-friendly antibacterial coating products and promising for domestic, medical and industrial applications.

  12. Effects of refrigeration on the bactericidal activity of human milk: a preliminary study.

    Science.gov (United States)

    Martínez-Costa, Cecilia; Silvestre, María Dolores; López, María Carmen; Plaza, Auxiliadora; Miranda, María; Guijarro, Raquel

    2007-08-01

    This study analyzed the bactericidal activity of human milk and how it is influenced by refrigerated storage. Nine samples of mature human milk were collected and divided into 3 aliquots. One was analyzed immediately, and the other 2 were refrigerated at 4 degrees C to 6 degrees C for 48 and 72 hours, respectively. All of the fresh samples exhibited bactericidal activity with an average value of 83.47% +/- 18.37%. Refrigeration for 48 hours did not cause significant modifications, whereas storage beyond 72 hours significantly lowered the degree of bacteriolysis versus fresh milk. In conclusion, human milk possesses bactericidal activity that remains stable during the first 48 hours of refrigerated storage, but it is significantly reduced beyond 72 hours.

  13. The bactericidal effects of the respiratory burst and the myeloperoxidase system isolated in neutrophil cytoplasts.

    Science.gov (United States)

    Odell, E W; Segal, A W

    1988-10-07

    Neutrophil polymorphonuclear leucocytes kill bacteria by oxygen-dependent and oxygen-independent mechanisms. Many potentially toxic mechanisms have been described, but the complexity of the phagosomal environment and the synergy between oxidative and non-oxidative systems hamper the investigation of individual bactericidal mechanism in whole cells. Neutrophil cytoplasts are greatly depleted of granule proteins and permit the investigation of the bactericidal effects of the respiratory burst in isolation. In this study they have been used to examine the role of the respiratory burst and myeloperoxidase in oxygen-dependent killing of Staphylococcus aureus. Cytoplasts generated oxygen radicals at comparable rates to human neutrophils and phagocytosed but did not kill S. aureus. The selective reconstitution of the myeloperoxidase-hydrogen peroxide-halide system by coating bacteria with myeloperoxidase conferred on cytoplasts the ability to kill intracellular bacteria. However, extracellular killing by diffusible bactericidal factors was not detected in this system.

  14. Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against Escherichia coli.

    Science.gov (United States)

    Wang, Lian; He, Hong; Yu, Yunbo; Sun, Li; Liu, Sijin; Zhang, Changbin; He, Lian

    2014-06-01

    Silver-loaded CeO2 nanomaterials (Ag/CeO2) including Ag/CeO2 nanorods, nanocubes, nanoparticles were prepared with hydrothermal and impregnation methods. Catalytic inactivation of Escherichia coli with Ag/CeO2 catalysts through the formation of reactive oxygen species (ROS) was investigated. For comparison purposes, the bactericidal activities of CeO2 nanorods, nanocubes and nanoparticles were also studied. There was a 3-4 log order improvement in the inactivation of E. coli with Ag/CeO2 catalysts compared with CeO2 catalysts. Temperature-programmed reduction of H2 showed that Ag/CeO2 catalysts had higher catalytic oxidation ability than CeO2 catalysts, which was the reason for that Ag/CeO2 catalysts exhibited stronger bactericidal activities than CeO2 catalysts. Further, the bactericidal activities of CeO2 and Ag/CeO2 depend on their shapes. Results of 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping measurements by electron spin resonance and addition of catalase as a scavenger indicated the formation of OH, O2(-), and H2O2, which caused the obvious bactericidal activity of catalysts. The stronger chemical bond between Ag and CeO2 nanorods led to lower Ag(+) elution concentrations. The toxicity of Ag(+) eluted from the catalysts did not play an important role during the bactericidal process. Experimental results also indicated that Ag/CeO2 induced the production of intracellular ROS and disruption of the cell wall and cell membrane. A possible production mechanism of ROS and bactericidal mechanism of catalytic oxidation were proposed.

  15. Bactericidal Effects and Mechanism of Action of Olanexidine Gluconate, a New Antiseptic.

    Science.gov (United States)

    Hagi, Akifumi; Iwata, Koushi; Nii, Takuya; Nakata, Hikaru; Tsubotani, Yoshie; Inoue, Yasuhide

    2015-08-01

    Olanexidine gluconate [1-(3,4-dichlorobenzyl)-5-octylbiguanide gluconate] (development code OPB-2045G) is a new monobiguanide compound with bactericidal activity. In this study, we assessed its spectrum of bactericidal activity and mechanism of action. The minimal bactericidal concentrations of the compound for 30-, 60-, and 180-s exposures were determined with the microdilution method using a neutralizer against 320 bacterial strains from culture collections and clinical isolates. Based on the results, the estimated bactericidal olanexidine concentrations with 180-s exposures were 869 μg/ml for Gram-positive cocci (155 strains), 109 μg/ml for Gram-positive bacilli (29 strains), and 434 μg/ml for Gram-negative bacteria (136 strains). Olanexidine was active against a wide range of bacteria, especially Gram-positive cocci, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, and had a spectrum of bactericidal activity comparable to that of commercial antiseptics, such as chlorhexidine and povidone-iodine. In vitro experiments exploring its mechanism of action indicated that olanexidine (i) interacts with the bacterial surface molecules, such as lipopolysaccharide and lipoteichoic acid, (ii) disrupts the cell membranes of liposomes, which are artificial bacterial membrane models, (iii) enhances the membrane permeability of Escherichia coli, (iv) disrupts the membrane integrity of S. aureus, and (v) denatures proteins at relatively high concentrations (≥160 μg/ml). These results indicate that olanexidine probably binds to the cell membrane, disrupts membrane integrity, and its bacteriostatic and bactericidal effects are caused by irreversible leakage of intracellular components. At relatively high concentrations, olanexidine aggregates cells by denaturing proteins. This mechanism differs slightly from that of a similar biguanide compound, chlorhexidine.

  16. Influence of Rifampin Therapy on Serum Bactericidal Activity in the Presence of Cloxacillin and Vancomycin

    Directory of Open Access Journals (Sweden)

    Andrew MR Mackenzie

    1990-01-01

    Full Text Available In this study the effect of rifampin on serum inhibitory and serum bactericidal titres was examined. Sera were prepared from pooled human serum to contain vancomycin (10 mg/L, cloxacillin (5 mg/L or rifampin (1 mg/L, and the combinations cloxacillin/rifampin and vancomycin/rifampin. These five sera were tested by a microtitre method for serum inhibitory power and serum bactericidal titre against 11 strains of Staphylococcus aureus. A 48 h incubation period was required to detect full colony growth for subculture plates. It was found with all strains that the effect of the addition of rifampin to the other two antibiotics was to increase the serum inhibitory power, lower the serum bactericidal titre, increase the inhibitory/cidal ratio, and slow colony growth on subculture. In the clinical part of the study it was shown that only three of 38 sera (8% from patients receiving betalactam or vanomycin but not rifampin gave an inhibitory/cidal ratio greater than 8, but that nine of 10 sera (90% from patients receiving rifampin in addition to betalactam or vancomycin gave a ratio greater than 8 (P<0.001. The study verified that the effect of rifampin in serum was to increase inhibitory power and decrease bactericidal titre. The clinical significance of these results is not known and it is suggested that a high ratio of inhibitory to bactericidal titre in the presence of rifampin is to be expected, and that a low bactericidal titre under these circumstances is not necessarily an indication to modify therapy.

  17. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly

    Science.gov (United States)

    Mainwaring, David E.; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N.; Wu, Alex H.-F.; Marchant, Richard; Crawford, Russell J.; Ivanova, Elena P.

    2016-03-01

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron

  18. Use of lyophilized skin for testing the bactericidal activity of teat disinfectants.

    Science.gov (United States)

    Bramley, A J; Hogben, E M

    1983-02-01

    The bactericidal activities of various concentrations of 3 disinfectants commonly used for teat disinfection were compared in vitro using small discs of pig skin previously contaminated with Staphylococcus aureus. Solutions containing 40 g/l Na hypochlorite, 25 or 50 g/l chlorhexidine digluconate or iodophor containing 5 g/l iodine were found to have equivalent or superior bactericidal activity to a solution containing 10 g/l Na hypochlorite. This in vitro technique offers a convenient alternative to in vivo tests for teat disinfectants and with minor modifications could be applicable to the testing of skin antiseptics in general.

  19. INVOLVEMENT OF BACTERICIDAL FACTORS FROM THROMBIN-STIMULATED PLATELETS IN CLEARANCE OF ADHERENT VIRIDANS STREPTOCOCCI IN EXPERIMENTAL INFECTIVE ENDOCARDITIS

    NARCIS (Netherlands)

    VANDERWERFF, J; ZAAT, SAJ; JOLDERSMA, W; HESS, J

    1995-01-01

    Platelets activated with thrombin release bactericidal factors. We studied the role of the susceptibility of viridans streptococci to these bactericidal factors in the development of infective endocarditis (IE). By using the experimental endocarditis rabbit model, the initial adherence and the devel

  20. Direct comparison of Xpert MTB/RIF assay with liquid and solid mycobacterial culture for quantification of early bactericidal activity

    NARCIS (Netherlands)

    Kayigire, X.A.; Friedrich, S.O.; Venter, A.; Dawson, R.; Gillespie, S.H.; Boeree, M.J.; Heinrich, N.; Hoelscher, M.; Diacon, A.H.; Aarnoutse, R.

    2013-01-01

    The early bactericidal activity of antituberculosis agents is usually determined by measuring the reduction of the sputum mycobacterial load over time on solid agar medium or in liquid culture. This study investigated the value of a quantitative PCR assay for early bactericidal activity determinatio

  1. Anti-adherence and bactericidal activity of sphingolipids against Streptococcus mutans

    NARCIS (Netherlands)

    Cukkemane, N.; Bikker, F.J.; Nazmi, K.; Brand, H.S.; Sotres, J.; Lindh, L.; Arnebrant, T.; Veerman, E.C.I.

    2015-01-01

    This study evaluated the anti-biofilm activity of sphingosine, phytosphingosine (PHS), and sphinganine for: (i) anti-adherence activity on hydroxyapatite (HA) surfaces; and (ii) bactericidal activity on different Streptococcus mutans phenotypes (i.e. planktonic cells and cells from a disrupted biofi

  2. Integrated antifouling and bactericidal polymer membranes through bioinspired polydopamine/poly(N-vinyl pyrrolidone) coating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianghong [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Yuan, Shuaishuai [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Shi, Dean, E-mail: deanshi2012@yahoo.com [Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Yang, Yingkui; Jiang, Tao [Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Yan, Shunjie; Shi, Hengchong [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Luan, Shifang, E-mail: sfluan@ciac.ac.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Yin, Jinghua [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2016-07-01

    Graphical abstract: - Highlights: • Antifouling and bactericidal capabilities were facilely integrated into a surface via bioinspired coating. • The modification technique was very facile and universal to different types of substrate materials. • The integrated antifouling and bactericidal surfaces have great potential in wound dressing applications. - Abstract: Polypropylene (PP) non-woven has been widely used as wound dressing; however, the hydrophobic nature of PP can initiate bacterial attachment and subsequent biofilm formation. Herein, we propose a facile approach to functionalize PP non-woven with poly(ethylene glycol) (PEG) and poly(N-vinyl pyrrolidone)-iodine complex (PVP-I). PVP and PEG were successively tethered onto PP non-woven surface via versatile bioinspired dopamine (DA) chemistry, followed by complexing iodine with PVP moieties. It was demonstrated through the field emission scanning electron microscope (SEM) and spread plate method that the as-modified PP non-woven integrated both antifouling property of PEG for suppressing bacterial adhesion, and bactericidal property of PVP-I for killing the few adherent bacteria. Meanwhile, it could greatly resist platelet and red blood cell adhesion. The integrated antifouling and bactericidal PP non-woven surfaces might have great potential in various wound dressing applications.

  3. Influence of nano-MgO particle size on bactericidal action against Bacillus subtilis var. niger

    Institute of Scientific and Technical Information of China (English)

    HUANG Lei; LI Dianqing; LIN Yanjun; David G.Evans; DUAN Xue

    2005-01-01

    Nano-MgO with various particle sizes, synthesized by different methods using Mg(NO3)2·6H2O, Na2CO3, Na2SO4, urea and ammonia solution as reactants, was used to carry out bactericidal experiments on Bacillus subtilis var. niger. The results were compared with the effect of TiO2, a common kind of photocatalytic material. The materials were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), low temperature N2 adsorption-desorption measurements and FT-IR, and the results showed that the bactericidal ability of MgO increases with decreasing particle size. Nano-MgO and an interior wall-paint containing the material have better bactericidal effects than nono-TiO2 in both presence and absence of light. The bactericidal mechanism is discussed. The surface of MgO can generate high concentrations of which is highly active and can react with the peptide linkages in the coating walls of the spores. The spores are destroyed by the resulting damage to their structure.

  4. Characterization and activity of an immobilized antimicrobial peptide containing bactericidal PEG-hydrogel

    NARCIS (Netherlands)

    Cleophas, Rik T C; Sjollema, Jelmer; Busscher, Henk J; Kruijtzer, John A W; Liskamp, Rob M J

    2014-01-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein s

  5. Peroxiredoxin-3 Is Involved in Bactericidal Activity through the Regulation of Mitochondrial Reactive Oxygen Species

    Science.gov (United States)

    Lee, Sena; Wi, Sae Mi; Min, Yoon

    2016-01-01

    Peroxiredoxin-3 (Prdx3) is a mitochondrial protein of the thioredoxin family of antioxidant peroxidases and is the principal peroxidase responsible for metabolizing mitochondrial hydrogen peroxide. Recent reports have shown that mitochondrial reactive oxygen species (mROS) contribute to macrophage-mediated bactericidal activity in response to Toll-like receptors. Herein, we investigated the functional effect of Prdx3 in bactericidal activity. The mitochondrial localization of Prdx3 in HEK293T cells was confirmed by cell fractionation and confocal microscopy analyses. To investigate the functional role of Prdx3 in bactericidal activity, Prdx3-knockdown (Prdx3KD) THP-1 cells were generated. The mROS levels in Prdx3KD THP-1 cells were significantly higher than those in control THP-1 cells. Moreover, the mROS levels were markedly increased in response to lipopolysaccharide. Notably, the Salmonella enterica serovar Typhimurium infection assay revealed that the Prdx3KD THP-1 cells were significantly resistant to S. Typhimurium infection, as compared with control THP-1 cells. Taken together, these results indicate that Prdx3 is functionally important in bactericidal activity through the regulation of mROS. PMID:28035213

  6. Bactericidal Action of Photo-Irradiated Aqueous Extracts from the Residue of Crushed Grapes from Winemaking.

    Science.gov (United States)

    Tsukada, Mana; Sheng, Hong; Tada, Mika; Mokudai, Takayuki; Oizumi, Satomi; Kamachi, Toshiaki; Niwano, Yoshimi

    2016-01-01

    Our previous studies revealed that photo-irradiation of polyphenols could exert bactericidal action via reactive oxygen species (ROS). In the present study, the photo-irradiation-induced bactericidal activity of the aqueous extract from the residue of crushed grapes from winemaking was investigated in relation to ROS formation. Staphylococcus aureus suspended in the extract was irradiated with LED light at 400 nm. This solution killed the bacteria, and a 3-4 log and a >5-log reduction of the viable counts were observed within 10 and 20 min, respectively. LED light irradiation alone also killed the bacteria, but the viable counts were 2-4 log higher than those of the photo-irradiated extract. In contrast, almost no change occurred in the suspension without LED irradiation. When hydroxyl radical scavengers were added to the suspension, the bactericidal effect of the photo-irradiated extract was attenuated. Furthermore, electron spin resonance analysis demonstrated that hydroxyl radicals were generated by the photo-irradiation of the extract. The present study suggests that polyphenolic compounds in the extract exert bactericidal activity via hydroxyl radical formation upon photo-irradiation.

  7. Predicting of bactericidal activity of chemical disinfectants using disinfection activity coefficient of solution

    OpenAIRE

    Gjorgjeska, Biljana

    2011-01-01

    There is the need for defining standard technique for quantitative determination of bactericidal activity of chemical disinfectant substances, as well as the need for defining parameter for comparing various chemical disinfectants. The methods which are usually used for evaluation of antiseptic activity of disinfectant aqueous solutions are microbiological.

  8. Bactericidal and wound-healing properties of sodium hypochlorite solutions: the 1991 Lindberg Award.

    Science.gov (United States)

    Heggers, J P; Sazy, J A; Stenberg, B D; Strock, L L; McCauley, R L; Herndon, D N; Robson, M C

    1991-01-01

    Toxic effects of sodium hypochlorite on wound healing elements have been confined to a restricted range of sodium hypochlorite concentrations. We investigated concentrations of sodium hypochlorite for antibacterial activity and tissue toxicity at varying time intervals. We attempted to find the efficacious therapeutic concentration that was both microbicidal and nontoxic. Gram-negative and gram-positive isolates (0.1/ml of 1 x 10(8)/ml) were introduced into various concentrations of buffered and unbuffered sodium hypochlorite solutions for determinations of bactericidal activity at 5-, 10-, 15-, and 30-minute intervals. Concentrations of sodium hypochlorite were 0.25%, 0.025%, and 0.0125%. In vitro assays with fibroblasts at the same concentrations were also performed to determine toxicity at the same time intervals. An in vivo incisional model was also used to determine the effects of sodium hypochlorite therapy on wound healing. Bactericidal effects were observed for concentrations as low as 0.025%. Tissue toxicity, both in vitro and in vivo, was observed at concentrations of 0.25% but not at a concentration of 0.025%. Although concentrations below this level were nontoxic, they were not bactericidal. Therefore a modified "Dakin's" solution at a concentration of 0.025% is therapeutically efficacious as a fluid dressing, since it preserves bactericidal properties and eliminates the detrimental potential on wound healing.

  9. Increased bactericidal activity of colistin on Pseudomonas aeruginosa biofilms in anaerobic conditions

    DEFF Research Database (Denmark)

    Kolpen, Mette; Appeldorff, Cecilie F.; Brandt, Sarah;

    2016-01-01

    that production of OH˙may not contribute significantly to the bactericidal activity of colistin on P. aeruginosa biofilm. Thus, we investigated the effect of colistin treatment on biofilm of wild-type PAO1, a catalase-deficient mutant (katA) and a colistin-resistant CF isolate cultured in microtiter plates...

  10. Synergistic bactericidal activity of Ag-TiO₂ nanoparticles in both light and dark conditions.

    Science.gov (United States)

    Li, Minghua; Noriega-Trevino, Maria Eugenia; Nino-Martinez, Nereyda; Marambio-Jones, Catalina; Wang, Jinwen; Damoiseaux, Robert; Ruiz, Facundo; Hoek, Eric M V

    2011-10-15

    High-throughput screening was employed to evaluate bactericidal activities of hybrid Ag-TiO₂ nanoparticles comprising variations in TiO₂ crystalline phase, Ag content, and synthesis method. Hybrid Ag-TiO₂ nanoparticles were prepared by either wet-impregnation or UV photo deposition onto both Degussa P25 and DuPont R902 TiO₂ nanoparticles. The presence of Ag was confirmed by ICP, TEM, and XRD analysis. The size of Ag nanoparticles formed on anatase/rutile P25 TiO₂ nanoparticles was smaller than those formed on pure rutile R902. When activated by UV light, all hybrid Ag-TiO₂ nanoparticles exhibited stronger bactericidal activity than UV alone, Ag/UV, or UV/TiO₂. For experiments conducted in the dark, bactericidal activity of Ag-TiO₂ nanoparticles was greater than either bare TiO₂ (inert) or pure Ag nanoparticles, suggesting that the hybrid materials produced a synergistic antibacterial effect unrelated to photoactivity. Moreover, less Ag(+) dissolved from Ag-TiO₂ nanoparticles than from Ag nanoparticles, indicating the antibacterial activities of Ag-TiO₂ was not only caused by releasing of toxic metal ions. It is clear that nanotechnology can produce more effective bactericides; however, the challenge remains to identify practical ways to take advantage of these exciting new material properties.

  11. Influence of pulmonary surfactant on in vitro bactericidal activities of amoxicillin, ceftazidime, and tobramycin

    NARCIS (Netherlands)

    A. van 't Veen (Annemarie); J.W. Mouton (Johan); D.A.M.P.J. Gommers (Diederik); J.A.J.W. Kluytmans (Jan); P. Dekkers; B.F. Lachmann (Burkhard)

    1995-01-01

    textabstractThe influence of a natural pulmonary surfactant on antibiotic activity was investigated to assess the possible use of exogenous surfactant as a vehicle for antibiotic delivery to the lung. The influence of surfactant on the bactericidal activity of amoxicill

  12. Increased bactericidal activity of colistin on Pseudomonas aeruginosa biofilms in anaerobic conditions

    DEFF Research Database (Denmark)

    Mette, Kolpen; Appeldorff, Cecilie F; Brandt, Sarah;

    2016-01-01

    that production of OH⋅ may not contribute significantly to the bactericidal activity of colistin on P. aeruginosa biofilm. Thus, we investigated the effect of colistin treatment on biofilm of wildtype PAO1, a catalase deficient mutant (ΔkatA) and a colistin resistant CF isolate cultured in microtiter plates...

  13. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly.

    Science.gov (United States)

    Mainwaring, David E; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N; Wu, Alex H-F; Marchant, Richard; Crawford, Russell J; Ivanova, Elena P

    2016-03-28

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.

  14. Characterization and Activity of an Immobilized Antimicrobial Peptide Containing Bactericidal PEG-Hydrogel

    NARCIS (Netherlands)

    Cleophas, Rik T. C.; Sjollema, Jelmer; Busscher, Henk J.; Kruijtzer, John A. W.; Liskamp, Rob M. J.

    2014-01-01

    A single step immobilization-polymerization strategy of a highly active antimicrobial peptide into a soft hydrogel network on a poly(ethylene terephthalate) surface using thiol-ene chemistry is described. The bactericidal hydrogel was molecularly characterized via Coomassie and Lowry assay protein s

  15. Bactericidal effect of S-nitrosothiols against clinical isolates from keratitis

    Directory of Open Access Journals (Sweden)

    de Oliveira MG

    2012-11-01

    Full Text Available Angelino Julio Cariello,1 Paulo José Martins Bispo,2 Gabriela Freitas Pereira de Souza,3 Antonio Carlos Campos Pignatari,2 Marcelo Ganzarolli de Oliveira,3 Ana Luisa Hofling-Lima11Department of Ophthalmology, 2Division of Infectious Diseases, Federal University of São Paulo, 3Institute of Chemistry, University of Campinas, Campinas, São Paulo, BrazilBackground: The purpose of this study was to evaluate the antimicrobial activity of two nitric oxide donors, ie, S-nitrosoglutathione (GSNO and S-nitroso-N-acetylcysteine (SNAC, against clinical isolates from patients with infectious keratitis.Methods: Reference broth microdilution assays were performed to determine the minimum inhibitory and bactericidal concentrations for GSNO and SNAC against four American Type Culture Collection strains and 52 clinical isolates from patients with infectious keratitis as follows: 14 (26.9% Pseudomonas species; 13 (25.0% coagulase-negative Staphylococci; 10 (19.2% Staphylococcus aureus; nine (17.3% Serratia marcescens; and six (11.5% Enterobacter aerogenes. Sterility control and bacterial growth control were also performed.Results: SNAC showed lower minimum inhibitory and bactericidal concentrations than GSNO for all clinical isolates from patients with infectious keratitis. For Gram-positive bacteria, mean minimum inhibitory and bactericidal concentrations were 2.1 ± 1.3 and 8.6 ± 3.8 mM for SNAC and 4.6 ± 3.2 and 21.5 ± 12.5 mM for GSNO (P < 0.01. For Gram-negative bacteria, mean minimum inhibitory and bactericidal concentrations were 3.3 ± 1.4 and 6.1 ± 3.4 mM for SNAC and 12.4 ± 5.4 and 26.5 ± 10.1 mM for GSNO (P < 0.01. The minimum bactericidal to inhibitory concentration ratio was ≤8 in 100% of all isolates tested for SNAC and in 94.2% tested for GSNO.Conclusions: SNAC and GSNO had effective inhibitory and bactericidal effects against bacterial isolates from keratitis. SNAC showed greater antimicrobial activity than GSNO against all bacteria

  16. A complex of equine lysozyme and oleic acid with bactericidal activity against Streptococcus pneumoniae.

    Science.gov (United States)

    Clementi, Emily A; Wilhelm, Kristina R; Schleucher, Jürgen; Morozova-Roche, Ludmilla A; Hakansson, Anders P

    2013-01-01

    HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize and/or present the

  17. A complex of equine lysozyme and oleic acid with bactericidal activity against Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Emily A Clementi

    Full Text Available HAMLET and ELOA are complexes consisting of oleic acid and two homologous, yet functionally different, proteins with cytotoxic activities against mammalian cells, with HAMLET showing higher tumor cells specificity, possibly due to the difference in propensity for oleic acid binding, as HAMLET binds 5-8 oleic acid molecules per protein molecule and ELOA binds 11-48 oleic acids. HAMLET has been shown to possess bactericidal activity against a number of bacterial species, particularly those with a respiratory tropism, with Streptococcus pneumoniae displaying the greatest degree of sensitivity. We show here that ELOA also displays bactericidal activity against pneumococci, which at lower concentrations shows mechanistic similarities to HAMLET's bactericidal activity. ELOA binds to S. pneumoniae and causes perturbations of the plasma membrane, including depolarization and subsequent rupture, and activates an influx of calcium into the cells. Selective inhibition of calcium channels and sodium/calcium exchange activity significantly diminished ELOA's bactericidal activity, similar to what we have observed with HAMLET. Finally, ELOA-induced death was also accompanied by DNA fragmentation into high molecular weight fragments - an apoptosis-like morphological phenotype that is seen during HAMLET-induced death. Thus, in contrast to different mechanisms of eukaryote cell death induced by ELOA and HAMLET, these complexes are characterized by rather similar activities towards bacteria. Although the majority of these events could be mimicked using oleic acid alone, the concentrations of oleic acid required were significantly higher than those present in the ELOA complex, and for some assays, the results were not identical between oleic acid alone and the ELOA complex. This indicates that the lipid, as a common denominator in both complexes, is an important component for the complexes' bactericidal activities, while the proteins are required both to solubilize

  18. Bactericidal Performance of Flame-Sprayed Nanostructured Titania-Copper Composite Coatings

    Science.gov (United States)

    George, N.; Mahon, M.; McDonald, A.

    2010-09-01

    A large concern surrounding stainless steel surfaces is the ability of bacteria to grow and attach to them quite easily. One possible solution to destroy these pathogens is to coat surfaces with a biocidal agent. The photocatalytic effect of titanium dioxide (TiO2) is known to have a bactericidal effect. Coatings of TiO2 were prepared on 1010 low carbon steel substrates using an oxy-acetylene flame spray torch. TiO2 coatings containing 5 wt.% copper (Cu) were fabricated to increase the bactericidal effect of the coating. After deposition, the coatings were polished to an average roughness of 1 μm. Solutions of Pseudomonas aeruginosa (PAK) bacteria were placed onto the coating surface for periods of up to 3 h, and the amount of surviving bacteria were counted. Some samples were irradiated with white light and other samples were held in a dark chamber. In coatings of copper-free flame-sprayed TiO2, the high flame temperatures facilitated the conversion of the anatase phase to the rutile phase, which limited the photocatalytic destruction of the bacterial cells. However, TiO2-copper composite coatings showed a large bactericidal effect, killing approximately 75% of PAK bacterial cells after 3 h. Under the same conditions, the TiO2-copper composite coatings had the same bactericidal capabilities as pure copper surfaces, with the composite coatings showing improved bactericidal performance when exposed to light. It was proposed that increased concentrations of reactive oxide species produced due to TiO2 photocatalysis improved the performance of the irradiated TiO2-copper composite coatings.

  19. Serum bactericidal activity in a secondary school population following an outbreak of meningococcal disease: effects of carriage and secretor status.

    Science.gov (United States)

    Zorgani, A A; James, V S; Stewart, J; Blackwell, C C; Elton, R A; Weir, D M

    1996-06-01

    Sera obtained from 106 children following an outbreak of Neisseria meningitidis (B:4:P1.15) were screened for bactericidal antibodies against isolates of meningococci and Neisseria lactamica. Most had high titres of antibodies to N. lactamica and N. meningitidis NG:4:- but not to capsulate isolates: B:4:P1.15; B:15:P1.16; B:4:-; C:4:-. Bactericidal activity was higher for both carriers and secretors but the differences were not significant. Bactericidal activity was not associated with total or specific IgA or IgM. Carriers had significantly higher levels of IgG to N. lactamica but not to NG:4:- in sera with bactericidal activity for each of the capsulate strains. Among non-carriers, higher levels of IgG to N. lactamica were associated with killing of B:4:P1.15 and B:4:-. Secretors' sera with bactericidal activity had significantly higher levels of IgG to N. lactamica compared with sera that were not bactericidal. This was not observed among non-secretors. Antibodies to the outbreak strain were adsorbed by all Neisseria isolates tested and absorption of sera with N. lactamica alone completely removed the bactericidal activity against the outbreak strain.

  20. Spectrally selective UV bactericidal effect for curative treatment of post-surgical intra-abdominal abscesses and other infections

    Science.gov (United States)

    Dudelzak, Alexander E.; Miller, Mark A.; Babichenko, Sergey M.

    2004-07-01

    Results of in-vitro studies of bactericidal effects of ultraviolet (UV) irradiation on strains causing drug-resistant endo-cavital infections (Enterococcus, Staphylococcus aureus, Pseudomonas aeruginosa, and others) are presented. An original technique to measure effects of UV-irradiation on bacterial growth at different wavelengths has been developed. Spectral dependences of the bactericidal effect have been observed, and spectral maxima of bactericidal efficiency have been found. Applications to curative treatments of wounds, post-surgical intra-abdominal abscesses and other diseases are discussed.

  1. Bactericidal Activity of Oleo-gum Resins Doped with Metal Oxides

    Directory of Open Access Journals (Sweden)

    MSc Diogo José Horst

    2016-12-01

    Full Text Available This work aimed to evaluate the bactericidal activity of vegetable oil-gum resins (Styrax benzoin, Commiphora mirrha, and Boswellia papyrifera doped with metal oxides (TiO2, P25, MoO3 e Cu2O in nanometric dimension. The in vitro susceptibility of pathogenic Gram-negative bacteria E. coli was accessed. The antibiogram essay was performed using the semi-quantitative method Kirby-Bauer (KB agar diffusion test. The materials obtained were characterized by ultraviolet visible (UV-Vis spectrophotometry, additionally; its morphology was characterized by scanning electron microscopy (SEM. The results show that in most cases the materials present bactericidal activity, thereby inhibiting both planktonic and surface associated growth of this microorganism.

  2. Invasive African Salmonella Typhimurium induces bactericidal antibodies against O-antigens.

    Science.gov (United States)

    Rondini, Simona; Lanzilao, Luisa; Necchi, Francesca; O'Shaughnessy, Colette M; Micoli, Francesca; Saul, Allan; MacLennan, Calman A

    2013-10-01

    Nontyphoidal Salmonella are a major and emerging cause of fatal invasive disease in Africa, and are genetically distinct from those found elsewhere in the world. Understanding the targets of protective immunity to these African Salmonellae is key to vaccine development. We immunized mice and rabbits with heat-inactivated wild-type African invasive Salmonella Typhimurium D23580 and rough mutants lacking O-antigen. Wild-type Salmonella, unlike rough bacteria, induced a large bactericidal antibody response mainly against O-antigen. Bactericidal ability of anti-O-antigen antibodies was confirmed following purification by affinity chromatography. The current findings support the development of an O-antigen conjugate vaccine against invasive nontyphoidal Salmonellae for Africa.

  3. Bactericidal Antibiotics Induce Toxic Metabolic Perturbations that Lead to Cellular Damage.

    Science.gov (United States)

    Belenky, Peter; Ye, Jonathan D; Porter, Caroline B M; Cohen, Nadia R; Lobritz, Michael A; Ferrante, Thomas; Jain, Saloni; Korry, Benjamin J; Schwarz, Eric G; Walker, Graham C; Collins, James J

    2015-11-03

    Understanding how antibiotics impact bacterial metabolism may provide insight into their mechanisms of action and could lead to enhanced therapeutic methodologies. Here, we profiled the metabolome of Escherichia coli after treatment with three different classes of bactericidal antibiotics (?-lactams, aminoglycosides, quinolones). These treatments induced a similar set of metabolic changes after 30 min that then diverged into more distinct profiles at later time points. The most striking changes corresponded to elevated concentrations of central carbon metabolites, active breakdown of the nucleotide pool, reduced lipid levels, and evidence of an elevated redox state. We examined potential end-target consequences of these metabolic perturbations and found that antibiotic-treated cells exhibited cytotoxic changes indicative of oxidative stress, including higher levels of protein carbonylation, malondialdehyde adducts, nucleotide oxidation, and double-strand DNA breaks. This work shows that bactericidal antibiotics induce a complex set of metabolic changes that are correlated with the buildup of toxic metabolic by-products.

  4. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    Science.gov (United States)

    Vanhoof, R; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-07-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) were resistant to erythromycin. One strain (1.2%) was completely resistant to tobramycin. The tetracyclines (tetracyline, doxycycline, minocycline) were generally effective, but 8% of the strains were totally resistant to them. Minocycline was the most active. Chloramphenicol, thiamphenicol, and clindamycin had good activity. The bacteriostatic and bactericidal distributions for colistin, nalidixic acid, and metronidazole were broad.

  5. Cefodizime (HR 221) potentiation of human neutrophil oxygen-independent bactericidal activity.

    Science.gov (United States)

    Labro, M T; Amit, N; Babin-Chevaye, C; Hakim, J

    1987-03-01

    The enhanced bactericidal activity of human neutrophils induced by cefotaxime and cefodizime, two methoxy-imino-amino- 2-thiazolyl cephalosporins, is linked to the cell stimulation of oxygen-dependent and oxygen-independent killing systems, respectively. Cefotaxime enhances both the killing and the oxidative response of neutrophils to opsonized particulate stimuli (bacteria for both activities and opsonized zymosan for the oxidative burst). These effects were not observed with non-opsonized particles (bacteria or zymosan) or soluble stimuli. On the contrary, cefodizime enhances killing of opsonized and non-opsonized bacteria by neutrophils regardless of treatment with phenylbutazone which blocks neutrophil oxidative metabolism. Cefodizime does not universally alter the oxidative burst induced by various stimuli, but has been shown to enhance the bactericidal activity of crude extracts of neutrophil granules. The data suggest that cefodizime and non O2-dependent killing systems of neutrophils cooperate in killing bacteria.

  6. Integrated antifouling and bactericidal polymer membranes through bioinspired polydopamine/poly(N-vinyl pyrrolidone) coating

    Science.gov (United States)

    Wang, Xianghong; Yuan, Shuaishuai; Shi, Dean; Yang, Yingkui; Jiang, Tao; Yan, Shunjie; Shi, Hengchong; Luan, Shifang; Yin, Jinghua

    2016-07-01

    Polypropylene (PP) non-woven has been widely used as wound dressing; however, the hydrophobic nature of PP can initiate bacterial attachment and subsequent biofilm formation. Herein, we propose a facile approach to functionalize PP non-woven with poly(ethylene glycol) (PEG) and poly(N-vinyl pyrrolidone)-iodine complex (PVP-I). PVP and PEG were successively tethered onto PP non-woven surface via versatile bioinspired dopamine (DA) chemistry, followed by complexing iodine with PVP moieties. It was demonstrated through the field emission scanning electron microscope (SEM) and spread plate method that the as-modified PP non-woven integrated both antifouling property of PEG for suppressing bacterial adhesion, and bactericidal property of PVP-I for killing the few adherent bacteria. Meanwhile, it could greatly resist platelet and red blood cell adhesion. The integrated antifouling and bactericidal PP non-woven surfaces might have great potential in various wound dressing applications.

  7. Synthesis and bactericidal activities of novel pyrazole-l-carbothioamide derivatives

    Institute of Scientific and Technical Information of China (English)

    LIU Xinhua; WANG Shifan; SONG Baoan

    2007-01-01

    4-(2-Hydroxy-phenyl)-but-3-en-2-one (1) was prepared via condensation of salicylaldehyde with acetone,and then reaction of the ketone 1 with thiosemicarbazide was accompanied by cyclization to give substituted pyrazole (2).Seven new 5-(2-hydroxy-phenyl)-3-methyl-4,5-dihydropyrazole- 1-carbothioamide derivatives (3a-3g) were synthesized by the acylation of 2 and characterized by means of elemental analysis,infrared (IR),and 1H nuclear magnetic resonance (NMR).The compounds 3c,3d,and 3g showed certain bactericidal activity against E.coli;while compound 3g showed certain bactericidal activity against P.vulgaris.

  8. Serum bactericidal effect on Pseudomonas aeruginosa isolates from cystic fibrosis patients.

    OpenAIRE

    Thomassen, M J; Demko, C A

    1981-01-01

    The bactericidal activity against Pseudomonas aeruginosa strains isolated from cystic fibrosis patients was determined in a 10% concentration of normal serum or autologous cystic fibrosis serum. Of the 167 strains tested, 77 (46%) were sensitive (greater than 95% killed) in normal serum. Mucoid strains were more frequently sensitive than nonmucoid strains. Twenty-three sensitive strains tested in ethyleneglycoltetraacetic acid-chelated serum were resistant (less than 10% killed), suggesting o...

  9. Bactericidal Permeability Increasing Protein Gene Polymorphism is Associated with Inflammatory Bowel Diseases in the Turkish Population

    OpenAIRE

    Güray Can; Hakan Akın; Filiz T. Özdemir; Hatice Can; Bülent Yılmaz; Fatih Eren; Özlen Atuğ; Belkıs Ünsal; Hamzaoğlu, Hülya O.

    2015-01-01

    Background/Aims: Inflammatory bowel disease, a chronic inflammatory disease with unknown etiology, affects the small and large bowel at different levels. It is increasingly considered that innate immune system may have a central position in the pathogenesis of the disease. As a part of the innate immune system, bactericidal permeability increasing protein has an important role in the recognition and neutralization of gram-negative bacteria. The aim of our study was to investigate the involvem...

  10. Bactericidal efficacy of elevated pH on fish pathogenic and environmental bacteria

    Science.gov (United States)

    Starliper, Clifford E.; Watten, Barnaby J.

    2013-01-01

    Ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. There is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. The present study employed laboratory methods to evaluate the bactericidal efficacy of increased pH (pH 10.0–12.0) for exposure durations of up to 72 h to kill a variety of Gram-negative and Gram-positive bacteria including fish pathogens (Aeromonas spp., Yersinia ruckeri, Edwardsiella ictaluri, Serratia liquefaciens, Carnobacterium sp.), other common aquatic-inhabitant bacteria (Serratia marcescens, Pseudomonas fluorescens, Staphylococcus sp., Bacillus sp.) and indicators listed in International Maritime Organization D2 Standards; namely, Vibrio cholera (an environmental isolate from fish), Escherichia coli and Enterococcus faecalis. Volumes of 5 N NaOH were added to tryptic soy broth to obtain desired pH adjustments. Viable cells were determined after 0, 4, 12, 24, 48, and 72 h. Initial (0 h) cell numbers ranged from 3.40 × 104 cfu/mL for Bacillus sp. to 2.44 × 107 cfu/mL for E. faecalis. The effective endpoints of pH and treatment duration necessary to realize 100% bactericidal effect varied; however, all bacteria tested were killed within 72 h at pH 12.0 or lower. The lowest parameters examined, 4 h at pH 10.0, were bactericidal to V. cholera, E. ictaluri, three of four isolates of E. coli, and (three of four) Aeromonas salmonicida subsp. salmonicida. Bactericidal effect was attained at pH 10.0 within 12 h for the other A. salmonicida subsp. salmonicida, and within 24 h for P. fluorescens, and the remaining E. coli.

  11. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    OpenAIRE

    Vanhoof, R.; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-01-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) wer...

  12. Microarray Bactericidal Testing of Natural Products Against Yersinia intermedia and Bacillus anthracis

    Science.gov (United States)

    2002-01-01

    Based Preservation Systems and Probiotic Bacteria. In Food Microbiology: Fundamentals and Frontiers. M. P. Doyle, L.R. Beuchat and T.J. Montville...from Lactococcus lactis, has these characteristics and in addition is a FDA GRAS food additive. Plant essential oils (e.g. oil of cloves, eucalyptus...etc) are attractive as BWA bactericides because of their historical use in the preservation of food , embalming and medicine. These oils and their

  13. Electrochemical analysis of the UV treated bactericidal Ti6Al4V surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pacha-Olivenza, Miguel A. [Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) (Spain); Department of Applied Physics, Faculty of Science, University of Extremadura, Av. Elvas s/n, 06071 Badajoz (Spain); Gallardo-Moreno, Amparo M., E-mail: amparogm@unex.es [Department of Applied Physics, Faculty of Science, University of Extremadura, Av. Elvas s/n, 06071 Badajoz (Spain); Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) (Spain); Vadillo-Rodríguez, Virginia; González-Martín, M. Luisa [Department of Applied Physics, Faculty of Science, University of Extremadura, Av. Elvas s/n, 06071 Badajoz (Spain); Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) (Spain); Pérez-Giraldo, Ciro [Department of Microbiology, Faculty of Medicine, University of Extremadura, Av. Elvas s/n, 06071 Badajoz (Spain); Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) (Spain); Galván, Juan C. [National Centre for Metallurgical Research (CENIM-CSIC), Av. Gregorio del Amo 8, 28040-Madrid (Spain)

    2013-04-01

    This research investigates in detail the bactericidal effect exhibited by the surface of the biomaterial Ti6Al4V after being subjected to UV-C light. It has been recently hypothesized that small surface currents, occurring as a consequence of the electron–hole pair recombination taking place after the excitation process, are behind the bactericidal properties displayed by this UV-treated material. To corroborate this hypothesis we have used different electrochemical techniques, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization plots and Mott–Schottky plots. EIS and Mott–Schottky plots have shown that UV-C treatment causes an initial increase on the surface electrical conduction of this material. In addition, EIS and polarization plots demonstrated that higher corrosion currents occur at the UV treated than at the non-irradiated samples. Despite this increase in the corrosion currents, EIS has also shown that such currents are not likely to affect the good stability of this material oxide film since the irradiated samples completely recovered the control values after being stored in dark conditions for a period not longer than 24 h. These results agree with the already-published in vitro transitory behavior of the bactericidal effect, which was shown to be present at initial times after the biomaterial implantation, a crucial moment to avoid a large number of biomaterial associated infections. Highlights: ► Bactericidal response of UV-treated Ti6Al4V is explained through electrochemistry. ► There is an increase in the superficial electrical conduction after UV-treatment. ► Higher corrosion currents for UV-treated against non-UV-treated samples are shown. ► EIS shows the recuperation on irradiated samples in agreement with microbial tests.

  14. Polymeric coatings eliminate the bactericidal effects of Nanoscale zero-valent iron to Escherichia coli

    Science.gov (United States)

    Lowry, G. V.; Gregory, K.; Li, Z.

    2009-12-01

    Nanoscale zero-valent iron (NZVI) particles that are used in aquifer remediation may come in contact with subsurface bacteria, and may adversely affect subsurface bacteria. Studies showed that NZVI is toxic toward E. coli at concentrations as low as a few mg/L. However, NZVI particles used in remediation are coated with polymers or natural organic matter (NOM). It is unclear how these surface coatings may affect the bactericidal properties of NZVI. The objectives of this study were to assess the effect that (i) coatings (both anthropogenic and natural) and (ii) particle oxidative state have on the bactericidal properties of NZVI on a gram-negative bacteria, Escherichia coli. Bacteria (106 cells/L) were exposed to 100 mg/L of bare or coated NZVI for 60 minutes under either aerobic or anaerobic conditions. Bacteria were plated at specified times over 60 minutes to determine the number of viable bacteria in the reactor. Bare NZVI was cytotoxic at only 100 mg/L NZVI with over 5 log kill after 60 minutes of exposure. Exposure under aerobic conditions resulted in less than 1 log kill. The lower bactericidal effects were due to rapid oxidation of the iron to Fe(II) and Fe(III) mineral phases that are not toxic. All organic coatings on NZVI decreased or eliminated NZVI cytotoxicity when exposed at the same NZVI concentrations as in the bare case. The decrease in bactericidal effects of coated NZVI over bare NZVI was due to electrosteric repulsions afforded by the coatings that inhibited contact of NZVI with the bacteria. The inhibition of attachment to bacteria was confirmed with TEM and with NZVI sedimentation studies. Application of coatings may be considered as a means of decreasing the effects of NZVI on subsurface bacteria in field application.

  15. Bactericidal efficacy of elevated pH on fish pathogenic and environmental bacteria

    Directory of Open Access Journals (Sweden)

    Clifford E. Starliper

    2013-07-01

    Full Text Available Ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. There is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. The present study employed laboratory methods to evaluate the bactericidal efficacy of increased pH (pH 10.0–12.0 for exposure durations of up to 72 h to kill a variety of Gram-negative and Gram-positive bacteria including fish pathogens (Aeromonas spp., Yersinia ruckeri, Edwardsiella ictaluri, Serratia liquefaciens, Carnobacterium sp., other common aquatic-inhabitant bacteria (Serratia marcescens, Pseudomonas fluorescens, Staphylococcus sp., Bacillus sp. and indicators listed in International Maritime Organization D2 Standards; namely, Vibrio cholera (an environmental isolate from fish, Escherichia coli and Enterococcus faecalis. Volumes of 5 N NaOH were added to tryptic soy broth to obtain desired pH adjustments. Viable cells were determined after 0, 4, 12, 24, 48, and 72 h. Initial (0 h cell numbers ranged from 3.40 × 104 cfu/mL for Bacillus sp. to 2.44 × 107 cfu/mL for E. faecalis. The effective endpoints of pH and treatment duration necessary to realize 100% bactericidal effect varied; however, all bacteria tested were killed within 72 h at pH 12.0 or lower. The lowest parameters examined, 4 h at pH 10.0, were bactericidal to V. cholera, E. ictaluri, three of four isolates of E. coli, and (three of four Aeromonas salmonicida subsp. salmonicida. Bactericidal effect was attained at pH 10.0 within 12 h for the other A. salmonicida subsp. salmonicida, and within 24 h for P. fluorescens, and the remaining E. coli.

  16. In vitro bactericidal activities of Japanese rice-fluid against Helicobacter pylori strains

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Kawakami, Kozue Oana, Masayoshi Hayama, Hiroyoshi Ota, Masahiko Takeuchi, Kazuhiro Miyashita, Tsunetomo Matsuzawa, Kiyomi Kanaya

    2006-01-01

    Full Text Available Background: Helicobacter pylori has now been widely recognized as a causative agent of gastroduodenal diseases. The development of safer anti- H. pylori compounds is desirable due to the antibiotic-resistant strains emerged to date. Methods: We successfully developed the compounds of Rice-fluid derived from unpolished, polished, and usually cooked Japanese rice, and investigated their in vitro antibacterial activities by means of the Time-Kill-Curve methods against various species of bacteria including H. pylori strains. Results: All of the compounds revealed keen bactericidal activities against H. pylori, followed by Streptococcus pneumoniae and Campylobacter jejuni strains, but failed to affect the viability of other bacterial species investigated including staphylococci, enterococci, Pseudomonas aeruginosa, and other gram-negative rods belonging to the family Enterobacteraceae. The bactericidal activities were demonstrated to be time- and concentration-dependent. Conclusions: The compounds of Rice-fluid are considered to be potentially new and safe therapeutic regimens against H. pylori infections. The mechanism of their bactericidal activities against H. pylori strains remains to be elucidated.

  17. A study on biocompatibility and bactericidal properties of pyrolytic carbon by silver ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Tang, H.Q. [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China); Liu, T. [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China); Liu, X. [Tianjin Urinary Surgery Institute, Tianjin 300211 (China); Gu, H.Q. [Tianjin Urinary Surgery Institute, Tianjin 300211 (China); Zhao, J. [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China)]. E-mail: jiezhao1943@126.com

    2007-02-15

    The biocompatibility and bactericidal properties of Ag{sup +}-implanted pyrolytic carbon were investigated by means of Staphylococcus aureus and Escherichia coli bacteria and some biocompatible experiments. The pyrolytic carbon samples were implanted by silver ions with the dose ranging from 5 x 10{sup 14} to 5 x 10{sup 18} ions/cm{sup 2} at an energy of 70 keV. The silver distribution in pyrolytic carbon was characterized by Rutherford Backscattering Spectrometry (RBS). The results show that the bactericidal rate for both S. aureus and E. coli increase with the ion dose when the silver ion dose is under the saturated dose of 5 x 10{sup 17} ions/cm{sup 2}. The bactericidal rate is over 97% when the ion dose exceeds that value. In comparison with the reference sample, Ag{sup +}-implanted pyrolytic carbon shows a good biocompatibility and without biotoxication by means of cytotoxicity, hemolysis and platelet tests. RBS analyses show that silver atoms penetrate into the sample surface and form a silver-rich surface region which plays an important role in killing bacteria. When the ion dose is not exceed 1 x 10{sup 16} ions/cm{sup 2}, the structure of Ag{sup +}-implanted pyrolytic carbon is kept unchanged maintaining the original biocompatibility.

  18. Immunological evaluation of Vi capsular polysaccharide of Salmonella enterica subsp. Typhi vaccine by serum bactericidal assay.

    Science.gov (United States)

    Ahmadi, H; Tabaraie, B; Maleknia, S; Shapouri, R; Nejati, M; Pour Mirza Gholi, F; Hedayati, M; Sadati, M; Zahednia, S; Sharifat Salmani, A

    2013-02-01

    Salmonella enterica subsp. Typhi (S. Typhi) Vi antigen capsular polysaccharide (Vi-CPS) is a licensed vaccine against typhoid fever. As there is no animal model for S. Typhi fever to evaluate the protective efficacy of the Vi-CPS vaccine, a serum bactericidal assay (SBA) is the recommended 'gold standard' to evaluate its potency. Vi-CPS was extracted from S. Typhi Ty6S (CSBPI-B191) using a modified Gotschlich method. Purified Vi-CPS (50 µg) was injected intramuscularly into three groups of five rabbits; group 2 received an additional booster dose of 50 µg Vi-CPS on day 15 and group 3 received two additional boosters on days 15 and 30. The sera obtained from each group were tested by SBA on days 0, 15, 30 and 45. The anti-Vi-CPS titres for groups 1, 2 and 3 on days 15, 30 and 45 were 4, 16 and 16; 4, 32 and 32; and 16, 64 and 64, respectively. Thus, Vi-CPS was shown to be a potent immunogen, as even one dose could induce an efficient bactericidal effect against S. Typhi. Although Vi-CPS is a reliable vaccine, sometimes depolymerization during purification can affect its potency, which can be resolved through a potency test. As the passive haemagglutination test recommended by the World Health Organization does not indicate vaccine potency, we recommend using an SBA to evaluate the bactericidal ability of Vi-CPS.

  19. Cationic Lipid Content in Liposome-Encapsulated Nisin Improves Sustainable Bactericidal Activity against Streptococcus mutans

    Science.gov (United States)

    Yamakami, Kazuo; Tsumori, Hideaki; Shimizu, Yoshitaka; Sakurai, Yutaka; Nagatoshi, Kohei; Sonomoto, Kenji

    2016-01-01

    An oral infectious disease, dental caries, is caused by the cariogenic streptococci Streptococcus mutans. The expected preventive efficiency for prophylactics against dental caries is not yet completely observed. Nisin, a bacteriocin, has been demonstrated to be microbicidal against S. mutans, and liposome-encapsulated nisin improves preventive features that may be exploited for human oral health. Here we examined the bactericidal effect of charged lipids on nisin-loaded liposomes against S. mutans and inhibitory efficiency for insoluble glucan synthesis by the streptococci for prevention of dental caries. Cationic liposome, nisin-loaded dipalmitoylphosphatidylcholine/phytosphingosine, exhibited higher bactericidal activities than those of electroneutral liposome and anionic liposome. Bactericidal efficiency of the cationic liposome revealed that the vesicles exhibited sustained inhibition of glucan synthesis and the lowest rate of release of nisin from the vesicles. The optimizing ability of cationic liposome-encapsulated nisin that exploit the sustained preventive features of an anti-streptococcal strategy may improve prevention of dental caries. PMID:27583045

  20. Bactericidal mechanisms revealed for rapid water disinfection by superabsorbent cryogels decorated with silver nanoparticles.

    Science.gov (United States)

    Loo, Siew-Leng; Krantz, William B; Fane, Anthony G; Gao, Yiben; Lim, Teik-Thye; Hu, Xiao

    2015-02-17

    The authors have recently reported the fabrication of superabsorbent cryogels decorated with silver nanoparticles (PSA/AgNP cryogels) that demonstrate rapid water disinfection. This paper provides a systematic elucidation of the bactericidal mechanisms of AgNPs (silver nanoparticles), both generally and in the specific context of cryogels. Direct contact between the PSA/AgNP cryogel interface and the bacterial cells is required to accomplish disinfection. Specifically, the disinfection efficacy is closely correlated to the cell-bound Ag concentration, which constitutes >90% of the Ag released. Cells exposed to PSA/AgNP cryogels show a significant depletion of intracellular adenosine triphosphate (ATP) content and cell-membrane lesions. A positive ROS (reactive oxygen species) scavenging test confirms the involvement of ROS (·O2(-), H2O2, and ·OH) in the bactericidal mechanism. Furthermore, exposed bacterial cells show an enhanced level of thiobarbituric acid reactive substances, indicating the occurrence of cell-membrane peroxidation mediated by ROS. In addition, this study reveals that both Ag(+) and Ag(0) are involved in the bactericidal mechanism of AgNPs via tests conducted using PSA cryogels with bound Ag(+) ions (or PSA/Ag(+) cryogels without reducing Ag(+) to Ag(0)). Significantly, bacterial cells exposed to PSA/Ag(+) cryogels did not show any cell-membrane damage even though the former had a higher cell-bound Ag concentration than that of the PSA/AgNP cryogels, thus indicating the differential action of Ag(+) and Ag(0).

  1. Broad-spectrum bactericidal activity of Ag(2)O-doped bioactive glass.

    Science.gov (United States)

    Bellantone, Maria; Williams, Huw D; Hench, Larry L

    2002-06-01

    Bioactive glass has found extensive application as an orthopedic and dental graft material and most recently also as a tissue engineering scaffold. Here we report an initial investigation of the in vitro antibacterial properties of AgBG, a novel bioactive glass composition doped with Ag(2)O. The bacteriostatic and bactericidal properties of this new material and of two other bioactive glass compositions, 45S5 Bioglass and BG, have been studied by using Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus as test microorganisms. Concentrations of AgBG in the range of 0.05 to 0.20 mg of AgBG per ml of culture medium were found to inhibit the growth of these bacteria. Not only was AgBG bacteriostatic, but it also elicited a rapid bactericidal action. A complete bactericidal effect was elicited within the first hours of incubation at AgBG concentrations of 10 mg ml(-1). 45S5 Bioglass and BG had no effect on bacterial growth or viability. The antibacterial action of AgBG is attributed exclusively to the leaching of Ag(+) ions from the glass matrix. Analytical measurements rule out any contribution to AgBG-mediated bacterial killing by changes in pH or ionic strength or the dissolution of other ionic species from the biomaterials. Our observations of the dissolution profiles of Ag(+) from AgBG in the presence and absence of bacteria are consistent with silver accumulation by the bacteria.

  2. [Bacteriostatic and/or bactericidal extract of Aloe vera gel on cultures of Listeria monocytogenes].

    Science.gov (United States)

    Ramírez Mérida, Luis Guillermo; Morón de Salim, Alba; Catinella, Rosangela; Castillo, Luis

    2012-03-01

    Listeria monocytogenes is a bacteria responsible for food borne diseases (FBD). The effect of Aloe vera gel extract as a possible bacteriostatic and/or bactericidal against Listeria monocytogenes, was checked by determined the minimum inhibitory concentration (MIC), the time of minimum inhibition (TMI) and minimum bactericidal concentration (MBC) solutions extract of Aloe vera gel in different concentrations on cultures of Listeria monocytogenes ATCC 7635. We applied the agar diffusion method, using solutions of extract of Aloe vera gel at concentrations of 0 to 100% for the MIC. The TMI was determined by growth curves in trypticase soy broth with an initial inoculum of Listeria monocytogenes ATCC 7635 of 108 CFU/mL in each solution. It was determined that the MIC was 10% extract of Aloe vera gel and TMI was 5 hours at concentrations of 10%, 20% and 30% of Aloe vera, while concentrations of 50, 80, 90 and 100%, the time was 8 hours. It was found that indeed the Aloe vera gel is bacteriostatic power on Listeria monocytogenes (p < 0.001), but yet, no bactericidal effect was obtained in our study.

  3. Development of bactericidal capacity and phagocytosis-associated metabolism of fetal pig leukocytes.

    Science.gov (United States)

    Holmes, B; Day, N; Haseman, J; Good, R A

    1972-02-01

    Evidence that the bactericidal ability and the stimulated oxidative metabolism of leukocytes appear in parallel during fetal development of the Minnesota Miniature pig has been obtained by application of the techniques applied to studies of human cells. It was demonstrated that leukocytes from 87- to 90-day fetuses were fully capable of ingesting Staphylococcus aureus but greatly diminished in bactericidal capacity as compared to leukocytes of older fetuses and adults. Although resting levels of oxygen consumption and hexose monophosphate pathway activity of leukocytes from the younger fetuses compared well with those of leukocytes from older animals, the phagocytosis-stimulated increments of metabolism were much less at 87 to 90 days of gestation than at later developmental stages. Both bactericidal capacity and increased metabolism of leukocytes reach adult levels by 100 days of gestation (normal gestation period of 115 to 120 days). Acrylamide gels stained for reduced nicotinamide adenine dinucleotide (NADH) and NADH phosphate (NADPH) diaphorase activity after disc electrophoresis of leukocyte extracts revealed normal mobility and intensity of NADH diaphorase bands. Three NADPH diaphorase bands were present in adult leukocyte extracts. Only the fast-migrating NADPH diaphorase band of 87- to 90-day cells stained with decreased intensity. This "deficiency" was no longer present at the later fetal period. The fast-migrating NADPH diaphorase band may represent an electron transfer protein which functions in cyanide-insensitive respiration of the leukocytes of the pig.

  4. Antibodies to lipooligosaccharide of a Brazilian purpuric fever isolate of Haemophilus influenzae biogroup aegyptius lack bactericidal and protective activity.

    Science.gov (United States)

    Peters, V B; Rubin, L G

    1992-08-01

    The immunological basis for protection against Brazilian purpuric fever (BPF), a fulminant infection of young children associated with bacteremia with Haemophilus influenzae biogroup aegyptius, is unknown. Candidate antigens to which protective antibodies may be directed include cell surface proteins and lipooligosaccharide (LOS). We studied the activity of antisera to LOS purified from a BPF H. influenzae biogroup aegyptius isolate. Anti-LOS antisera contained anti-LOS antibody by enzyme immunoassay and immunoblot and no detectable anti-outer membrane protein antibodies by immunoblot. Anti-LOS antisera had minimal bactericidal activity and were not protective against the homologous strain in an infant rat model of bacteremia. Antiserum to whole bacterial cells had a titer of anti-LOS antibody similar to that of anti-LOS antisera and was bactericidal and protective. Removal of anti-LOS antibodies from anti-whole cell antiserum by affinity chromatography did not result in a loss of bactericidal activity. Serum from a normal adult contained anti-LOS antibodies and had bactericidal activity. However, anti-LOS antibodies purified from this serum did not have detectable bactericidal activity. These studies suggest that anti-LOS antibodies produced in rats are not bactericidal and do not contribute to protection against experimental bacteremia with BPF strains of H. influenzae biogroup aegyptius.

  5. Time-kill determination of the bactericidal activity of telavancin and vancomycin against clinical methicillin-resistant Staphylococcus aureus isolates from cancer patients.

    Science.gov (United States)

    Rolston, Kenneth Vi; Wang, Weiqun; Nesher, Lior; Smith, Jordan R; Rybak, Michael J; Prince, Randall A

    2017-04-01

    The bactericidal activity of vancomycin and telavancin was compared against 4 clinical methicillin-resistant Staphylococcus aureus isolates recently recovered from cancer patients, using minimum bactericidal concentration (MBC):MIC ratios and time-kill studies. All 4 isolates were susceptible to both agents based on individual MIC values. The 2 methodologies for assessing bactericidal activity produced variable results. Telavancin appeared to have somewhat better bactericidal activity than vancomycin based on narrower MBC:MIC ratios. However, based on the results of the time-kill studies, neither agent demonstrated reliable bactericidal activity (defined as a ≥3 log10 reduction of the starting inoculum at the end of 24hours) against these organisms. These findings might be of some therapeutic importance in certain clinical settings and/or specific patient populations (such as febrile neutropenic patients) in whom potent bactericidal activity is either desired or preferred.

  6. Fabrication of nonfouling, bactericidal, and bacteria corpse release multifunctional surface through surface-initiated RAFT polymerization

    Directory of Open Access Journals (Sweden)

    Wang B

    2016-12-01

    Full Text Available Bailiang Wang,1,2 Zi Ye,1 Yihong Tang,1 Yuemei Han,1 Quankui Lin,1,2 Huihua Liu,2 Hao Chen,1,2 Kaihui Nan1,2 1School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 2Wenzhou Institute of Biomaterials and Engineering, Chinese Academy of Sciences, Wenzhou, People’s Republic of China Abstract: Infections after surgery or endophthalmitis are potentially blinding complications caused by bacterial adhesion and subsequent biofilm formation on the intraocular lens. Neither single-function anti-adhesion surface nor contacting killing surface can exhibit ideal antibacterial function. In this work, a novel (2-(dimethylamino-ethyl methacrylate-co-2-methacryloyloxyethyl phosphorylcholine (p (DMAEMA-co-MPC brush was synthesized by “grafting from” method through reversible–addition fragmentation chain transfer polymerization. 1-Bromoheptane was used to quaternize the p (DMAEMA-co-MPC brush coating and to endow the surface with bactericidal function. The success of the surface functionalization was confirmed by atomic force microscopy, water contact angle, and spectroscopic ellipsometry. The quaternary ammonium salt units were employed as efficient disinfection that can eliminate bacteria through contact killing, whereas the 2-methacryloyloxyethyl phosphorylcholine units were introduced to suppress unwanted nonspecific adsorption. The functionalized poly(dimethyl siloxane surfaces showed efficiency in reducing bovine serum albumin adsorption and in inhibiting bacteria adhesion and biofilm formation. The copolymer brushes also demonstrated excellent bactericidal function against gram-positive (Staphylococcus aureus bacteria measured by bacteria live/dead staining and shake-flask culture methods. The surface biocompatibility was evaluated by morphology and activity measurement with human lens epithelial cells in vitro. The achievement of the p (DMAEMA+-co-MPC copolymer brush coating with nonfouling, bactericidal, and

  7. Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water stored at different temperatures

    Science.gov (United States)

    Shen, Jin; Tian, Ying; Li, Yinglong; Ma, Ruonan; Zhang, Qian; Zhang, Jue; Fang, Jing

    2016-06-01

    Water activated by non-thermal plasma creates an acidified solution containing reactive oxygen and nitrogen species, known as plasma-activated water (PAW). The objective of this study was to investigate the effects of different storage temperatures (25 °C, 4 °C, ‑20 °C, ‑80 °C) on bactericidal activities against S. aureus and physicochemical properties of PAW up to 30 days. Interestingly, PAW stored at ‑80 °C yielded the best antibacterial activity against Staphylococcus aureus, 3~4 log reduction over a 30-day period after PAW generation; meanwhile, PAW stored at 25 °C, 4 °C, and ‑20 °C, respectively, yielded 0.2~2 log decrease in cell viability after the same exposure and storage time. These results were verified by scanning electron microscope (SEM). The physicochemical properties of PAW stored at different temperatures were evaluated, including pH, oxidation reduction potential (ORP), and hydrogen peroxide, nitrate, nitrite anion and NO radical levels. These findings suggested that bacterial activity of PAW stored at 25 °C, 4 °C, ‑20 °C decreased over time, and depended on three germicidal factors, specifically ORP, H2O2, and NO3‑. Moreover, PAW stored at ‑80 °C retained bactericidal activity, with NO2‑ contributing to bactericidal ability in association with H2O2. Our findings provide a basis for PAW storage and practical applications in disinfection and food preservation.

  8. N-Chlorotaurine and ammonium chloride: an antiseptic preparation with strong bactericidal activity.

    Science.gov (United States)

    Gottardi, Waldemar; Arnitz, Roland; Nagl, Markus

    2007-04-20

    The bactericidal activity of the endogenous antiseptic N-chlorotaurine (NCT) is significantly enhanced in the presence of ammonium chloride which induces the formation of monochloramine (NH(2)Cl) whose strong bactericidal activity is well known. In this study the properties of NCT plus ammonium chloride have been investigated. The reaction of active chlorine compounds like chloramine-T (N-chlorotoluene-sulfonamide sodium), chloroisocyanuric acid derivatives, hypochlorites (NaOCl, CaOCl(2)) with ammonium chloride did not stop at the stage of monochloramine, and the pungent smelling by-products di- and trichloramine, NHCl(2) and NCl(3), were also formed. This was not the case with NCT where only monochloramine was generated. The equilibrium constant of the reaction of NCT with ammonium was found to be [Formula: see text] , which allows to estimate the equilibrium concentration of monochloramine in aqueous solutions of NCT and ammonium chloride. At concentrations each ranging between 0.01% and 1.0% it comes to [NH(2)Cl]=3.5-254 ppm. As an unexpected result the monochloramine containing formulation turned out to be most stable in plain water without buffer additives. Quantitative killing assays revealed complete inactivation of 10(6) to 10(7)CFU/mL of seven bacterial strains by 0.1% NCT plus 0.1% ammonium chloride within 5 min, while with plain 0.1% NCT an incubation time of 2-4h was needed to achieve the same effect. The highly significant increase of bactericidal activity (200-300-fold) could be assigned to the presence of monochloramine which could be isolated by vacuum distillation. Aqueous solutions of NCT and ammonium chloride provide a highly effective and well tolerable antiseptic preparation appropriate to a treatment cycle of at least 1 month if stored in the refrigerator.

  9. Human Salivary Protein Histatin 5 Has Potent Bactericidal Activity against ESKAPE Pathogens

    Science.gov (United States)

    Du, Han; Puri, Sumant; McCall, Andrew; Norris, Hannah L.; Russo, Thomas; Edgerton, Mira

    2017-01-01

    ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter species) pathogens have characteristic multiple-drug resistance and cause an increasing number of nosocomial infections worldwide. Peptide-based therapeutics to treat ESKAPE infections might be an alternative to conventional antibiotics. Histatin 5 (Hst 5) is a salivary cationic histidine-rich peptide produced only in humans and higher primates. It has high antifungal activity against Candida albicans through an energy-dependent, non-lytic process; but its bactericidal effects are less known. We found Hst 5 has bactericidal activity against S. aureus (60–70% killing) and A. baumannii (85–90% killing) in 10 and 100 mM sodium phosphate buffer (NaPB), while killing of >99% of P. aeruginosa, 60–80% E. cloacae and 20–60% of E. faecium was found in 10 mM NaPB. Hst 5 killed 60% of biofilm cells of P. aeruginosa, but had reduced activity against biofilms of S. aureus and A. baumannii. Hst 5 killed 20% of K. pneumonia biofilm cells but not planktonic cells. Binding and uptake studies using FITC-labeled Hst 5 showed E. faecium and E. cloacae killing required Hst 5 internalization and was energy dependent, while bactericidal activity was rapid against P. aeruginosa and A. baumannii suggesting membrane disruption. Hst 5-mediated killing of S. aureus was both non-lytic and energy independent. Additionally, we found that spermidine conjugated Hst 5 (Hst5-Spd) had improved killing activity against E. faecium, E. cloacae, and A. baumannii. Hst 5 or its derivative has antibacterial activity against five out of six ESKAPE pathogens and may be an alternative treatment for these infections. PMID:28261570

  10. Bactericidal effects of plasma-modified surface chemistry of silicon nanograss

    Science.gov (United States)

    Ostrikov, Kola; Macgregor-Ramiasa, Melanie; Cavallaro, Alex; (Ken Ostrikov, Kostya; Vasilev, Krasimir

    2016-08-01

    The surface chemistry and topography of biomaterials regulate the adhesion and growth of microorganisms in ways that are still poorly understood. Silicon nanograss structures prepared via inductively coupled plasma etching were coated with plasma deposited nanometer-thin polymeric films to produce substrates with controlled topography and defined surface chemistry. The influence of surface properties on Staphylococcus aureus proliferation is demonstrated and explained in terms of nanograss substrate wetting behaviour. With the combination of the nanograss topography; hydrophilic plasma polymer coatings enhanced antimicrobial activity while hydrophobic coatings reduced it. This study advances the understanding of the effects of surface wettability on the bactericidal properties of reactive nano-engineered surfaces.

  11. Highly Bactericidal Polyurethane Effective Against Both Normal and Drug-Resistant Bacteria: Potential Use as an Air Filter Coating.

    Science.gov (United States)

    Taylor, Matthew; McCollister, Bruce; Park, Daewon

    2016-03-01

    The battle against the prevalence of hospital-acquired infections has underscored the importance of identifying and maintaining the cleanliness of possible infection transmission sources in the patient's environment. One of the most crucial lines of defense for mitigating the spread of pathogens in a healthcare facility is the removal of microorganisms from the environment by air filtration systems. After removing the pathogenic microorganisms, the filters used in these systems can serve as reservoirs for the pathogens and pose a risk for secondary infection. This threat, combined with the ever-growing prevalence of drug-resistant bacterial strains, substantiates the need for an effective bactericidal air filter. To this end, a broad-spectrum bactericidal polyurethane incorporating immobilized quaternary ammonium groups was developed for use as an air filter coating. In this study, the bactericidal activity of the polymer coating on high-efficiency particulate air (HEPA) filter samples was quantified against eight bacterial strains commonly responsible for nosocomial infection-including drug-resistant strains, and confirmed when applied as a filter coating in conditions mimicking those of its intended application. The coated HEPA filter samples exhibited high bactericidal activity against all eight strains, and the polyurethane was concluded to be an effective coating in rendering HEPA filters bactericidal.

  12. Evaluation of bactericidal effects of low-temperature nitrogen gas plasma towards application to short-time sterilization.

    Science.gov (United States)

    Kawamura, Kumiko; Sakuma, Ayaka; Nakamura, Yuka; Oguri, Tomoko; Sato, Natsumi; Kido, Nobuo

    2012-07-01

    To develop a novel low-temperature plasma sterilizer using pure N(2) gas as a plasma source, we evaluated bactericidal ability of a prototype apparatus provided by NGK Insulators. After determination of the sterilizing conditions without the cold spots, the D value of the BI of Geobacillus stearothermophilus endospores on the filter paper was determined as 1.9 min. However, the inactivation efficiency of BI carrying the same endospores on SUS varied to some extent, suggesting that the bactericidal effect might vary by materials of sterilized instruments. Staphylococcus aureus and Escherichia coli were also exposed to the N(2) gas plasma and confirmed to be inactivated within 30 min. Through the evaluation of bactericidal efficiency in a sterilization bag, we concluded that the UV photons in the plasma and the high-voltage pulse to generate the gas plasma were not concerned with the bactericidal effect of the N(2) gas plasma. Bactericidal effect might be exhibited by activated nitrogen atoms or molecular radicals.

  13. In vitro bactericidal activity of amoxicillin, gentamicin, rifampicin, ciprofloxacin and trimethoprim-sulfamethoxazole alone or in combination against Listeria monocytogenes.

    Science.gov (United States)

    Boisivon, A; Guiomar, C; Carbon, C

    1990-03-01

    The in vitro bactericidal activity of amoxicillin, gentamicin, rifampicin, ciprofloxacin and trimethoprim-sulfamethoxazole alone or in combination was determined against seven strains of Listeria monocytogenes by the killing curve method. Amoxicillin plus gentamicin was the most rapidly bactericidal combination, whereas trimethoprim-sulfamethoxazole was less bactericidal at 6 h but as bactericidal at 24 h. The combination of trimethoprim-sulfamethoxazole with either amoxicillin, ciprofloxacin or rifampicin did not result in antagonism, but the combinations were no more active than trimethoprim-sulfamethoxazole alone. The interaction of amoxicillin with rifampin was fairly antagonistic (1 log10 difference). The combination of amoxicillin and ciprofloxacin, although producing antagonism during the first 6 h, was more active at 24 h than amoxicillin alone and prevented the regrowth observed with ciprofloxacin alone. Ciprofloxacin and rifampicin interacted antagonistically during the first 6 h, and the combination was not very bactericidal (3 log10) but prevented the emergence of mutants, as observed with each drug alone, when used at concentrations greater than the MICs for the strain tested. These regimens merit evaluation in in vivo models of Listeria monocytogenes meningitis.

  14. 11. Bactericidal Activity of Photocatalytic TiO2 Excited by Low Intensity Pulsed Ultrasound (LIPUS): An In Vitro Study.

    Science.gov (United States)

    Noguchi, Chieko; Koseki, Hironobu

    2016-08-01

    Photocatalysis with anatase-type titanium dioxide (TiO2) under ultraviolet has a well-recognized bactericidal effect. The purpose of the present study was to evaluate the photocatalytic bactericidal effects of TiO2 on Staphylococcus epidermidis (ATCC35984) caused by Low Intensity Pulsed Ultrasound (LIPUS) associated with bio-implant-related infections. The photocatalytic properties of the TiO2 films were confirmed by the degradation of an aqueous solution of methylene blue. The disks were seeded with cultured Staphylococcus epidermidis and irradiated by LIPUS. The bactericidal effect of the TiO2 films was evaluated by counting the surviving colonies. The viability of the bacteria on the photocatalytic TiO2 film coated titanium was suppressed significantly to 63% after 2 hours of LIPUS treatment (P TiO2 under LIPUS is useful for sterilizing the contaminated and infected surfaces of metal bio-implants.

  15. Bactericidal Antibiotics Induce Toxic Metabolic Perturbations that Lead to Cellular Damage

    Directory of Open Access Journals (Sweden)

    Peter Belenky

    2015-11-01

    Full Text Available Understanding how antibiotics impact bacterial metabolism may provide insight into their mechanisms of action and could lead to enhanced therapeutic methodologies. Here, we profiled the metabolome of Escherichia coli after treatment with three different classes of bactericidal antibiotics (β-lactams, aminoglycosides, quinolones. These treatments induced a similar set of metabolic changes after 30 min that then diverged into more distinct profiles at later time points. The most striking changes corresponded to elevated concentrations of central carbon metabolites, active breakdown of the nucleotide pool, reduced lipid levels, and evidence of an elevated redox state. We examined potential end-target consequences of these metabolic perturbations and found that antibiotic-treated cells exhibited cytotoxic changes indicative of oxidative stress, including higher levels of protein carbonylation, malondialdehyde adducts, nucleotide oxidation, and double-strand DNA breaks. This work shows that bactericidal antibiotics induce a complex set of metabolic changes that are correlated with the buildup of toxic metabolic by-products.

  16. The susceptibility of Campylobacter concisus to the bactericidal effects of normal human serum.

    Science.gov (United States)

    Kirk, Karina Frahm; Nielsen, Hans Linde; Nielsen, Henrik

    2015-03-01

    Campylobacter concisus is an emerging pathogen of the gastrointestinal tract that has been associated with Barrett's oesophagus, enteritis and inflammatory bowel disease. Despite having invasive potential in intestinal epithelial cells in-vitro, bacteraemic cases with C. concisus are extremely scarce, having only been reported once. Therefore, we conducted a serum resistance assay to investigate the bactericidal effects of human complement on C. concisus in comparison to some other Campylobacter species. In total, 22 Campylobacter strains were tested by incubation with normal human serum and subsequent cultivation in microaerobic conditions for 48 hours. Killing time was evaluated by decrease in total CFU over time for incubation with different serum concentrations. Faecal isolates of C. concisus showed inoculum reduction to less than 50% after 30 min. Campylobacter jejuni was sensitive to serum, but killing was delayed and a bacteraemic Campylobacter fetus subsp. fetus isolate was completely serum resistant. Interestingly, sensitivity of enteric C. concisus to human serum was not associated to different faecal-calprotectin levels. We find that faecal isolates of C. concisus are sensitive to the bactericidal effects of serum, which may explain why C. concisus is not associated to bacteraemia.

  17. Bactericidal micron-thin sol-gel films prevent pin tract and periprosthetic infection.

    Science.gov (United States)

    Qu, Haibo; Knabe, Christine; Burke, Megan; Radin, Shula; Garino, Jonathan; Schaer, Thomas; Ducheyne, Paul

    2014-08-01

    Orthopedic injuries constitute the majority of wounds sustained by U.S. soldiers in recent conflicts. The risk of infection is considerable with fracture fixation devices. In this pilot study, we examined the use of unique bactericidal micron-thin sol-gel films on fracture fixation devices and their ability to prevent and eradicate infections. External fixation was studied with micron-thin sol-gel coated percutaneous pins releasing triclosan and inserted medially into rabbit tibiae. A total of 11 rabbits received percutaneous pins that were either uncoated or sol-gel/triclosan coated. Internal fracture fixation was also studied using sol-gel coated intramedullary (IM) nails releasing vancomycin in the intramedullary tibiae. Six sheep received IM nails that were coated with a sol-gel film that either contained vancomycin or did not contain vancomycin. All animals were challenged with Staphylococcus aureus around the implant. Animals were euthanized at 1 month postoperative. Rabbits receiving triclosan/sol-gel coated percutaneous pins did not show signs of infection. Uncoated percutaneous pins had a significantly higher infection rate. In the sheep study, there were no radiographic signs of osteomyelitis with vancomycin/sol-gel coated IM nails, in contrast to the observations in the control cohort. Hence, the nanostructured sol-gel controlled release technology offers the promise of a reliable and continuous delivery system of bactericidals from orthopedic devices to prevent and treat infection.

  18. Comprehensive bactericidal activity of an ethanol-based hand gel in 15 seconds

    Directory of Open Access Journals (Sweden)

    Kampf Günter

    2008-01-01

    Full Text Available Abstract Background Some studies indicate that the commonly recommended 30 s application time for the post contamination treatment of hands may not be necessary as the same effect may be achieved with some formulations in a shorter application time such as 15 s. Method We evaluated the bactericidal activity of an ethanol-based hand gel (Sterillium® Comfort Gel within 15 s in a time-kill-test against 11 Gram-positive, 16 Gram-negative bacteria and 11 emerging bacterial pathogens. Each strain was evaluated in quadruplicate. Results The hand gel (85% ethanol, w/w was found to reduce all 11 Gram-positive and all 16 Gram-negative bacteria by more than 5 log10 steps within 15 s, not only against the ATCC test strains but also against corresponding clinical isolates. In addition, a log10 reduction > 5 was observed against all tested emerging bacterial pathogens. Conclusion The ethanol-based hand gel was found to have a broad spectrum of bactericidal activity in only 15 s which includes the most common species causing nosocomial infections and the relevant emerging pathogens. Future research will hopefully help to find out if a shorter application time for the post contamination treatment of hands provides more benefits or more risks.

  19. Characterization of Mechanical and Bactericidal Properties of Cement Mortars Containing Waste Glass Aggregate and Nanomaterials

    Directory of Open Access Journals (Sweden)

    Pawel Sikora

    2016-08-01

    Full Text Available The recycling of waste glass is a major problem for municipalities worldwide. The problem concerns especially colored waste glass which, due to its low recycling rate as result of high level of impurity, has mostly been dumped into landfills. In recent years, a new use was found for it: instead of creating waste, it can be recycled as an additive in building materials. The aim of the study was to evaluate the possibility of manufacturing sustainable and self-cleaning cement mortars with use of commercially available nanomaterials and brown soda-lime waste glass. Mechanical and bactericidal properties of cement mortars containing brown soda-lime waste glass and commercially available nanomaterials (amorphous nanosilica and cement containing nanocrystalline titanium dioxide were analyzed in terms of waste glass content and the effectiveness of nanomaterials. Quartz sand is replaced with brown waste glass at ratios of 25%, 50%, 75% and 100% by weight. Study has shown that waste glass can act as a successful replacement for sand (up to 100% to produce cement mortars while nanosilica is incorporated. Additionally, a positive effect of waste glass aggregate for bactericidal properties of cement mortars was observed.

  20. Lysostaphin: use of a recombinant bactericidal enzyme as a mastitis therapeutic.

    Science.gov (United States)

    Oldham, E R; Daley, M J

    1991-12-01

    A recombinant mucolytic protein, lysostaphin, was evaluated as a potential intramammary therapeutic for Staphylococcus aureus mastitis in dairy cattle. Lysostaphin, a product of Staphylococcus simulans, enzymatically degrades the cell wall of Staphylococcus aureus and is bactericidal. Thirty Holstein-Freisian dairy cattle in their first lactation were infected with Staphylococcus aureus (Newbould 305, ATCC 29740) in all quarters. Infections were established and monitored for somatic cell counts and Staphylococcus aureus colony-forming units 3 wk prior to subsequent treatment. Infected animals were injected through the teat canal with a single dose of recombinant lysostaphin (dose response 1 to 500 mg) or after three successive p.m. milkings with 100 mg of recombinant lysostaphin in 60 ml of sterile phosphate-buffered saline. Animals were considered cured if the milk remained free of Staphylococcus aureus for a total of 28 milkings after last treatment. Kinetic analysis of immunologically active recombinant lysostaphin demonstrated that a minimum bactericidal concentration was maintained in the milk for up to 36 to 48 h after a single infusion of 100 mg of recombinant lysostaphin. The cure rate of quarters receiving recombinant lysostaphin (100 mg in sterile phosphate-buffered saline, administered over three consecutive p.m. milkings) was 20% compared with 29% for sodium cephapirin in saline and 57% for a commercial antibiotic formulation, respectively. An improved formulation of recombinant lysostaphin may prove to be an effective alternative to antibiotic therapy for bovine mastitis.

  1. Hydrothermal fabrication of ZSM-5 zeolites: biocompatibility, drug delivery property, and bactericidal property.

    Science.gov (United States)

    Guo, Ya-Ping; Long, Teng; Song, Zhen-Fu; Zhu, Zhen-An

    2014-04-01

    The bone graft-associated infection is widely considered in orthopedic surgery, which may lead to implant failure, extensive bone debridement, and increased patient morbidity. In this study, we fabricated ZSM-5 zeolites for drug delivery systems by hydrothermal method. The structure, morphology, biocompatibility, drug delivery property, and bactericidal property of the ZSM-5 zeolites were investigated. The ZSM-5 zeolites have mordenite framework inverted-type structure and exhibit the disk-like shape with the diameter of ∼350 nm and thickness of ∼165 nm. The biocompatibility tests indicate that human bone marrow stromal cells spread out well on the surfaces of the ZSM-5 zeolites and proliferate significantly with increasing culture time. As compared with the conventional hydroxyapatite particles, the ZSM-5 zeolites possess greater drug loading efficiency and drug sustained release property because of the ordered micropores, large Brunauer-Emmett-Teller (BET) surface areas, and functional groups. For the gentamicin-loaded ZSM-5 zeolites, the sustained release of gentamicin minimizes significantly bacterial adhesion and prevents biofilm formation against Staphylococcus epidermidis. The excellent biocompatibility, drug delivery property, and bactericidal property of the ZSM-5 zeolites suggest that they have great application potentials for treating implant-associated infections.

  2. Synergistic effect of proanthocyanidin on the bactericidal action of the photolysis of H2O2.

    Science.gov (United States)

    Ikai, Hiroyo; Nakamura, Keisuke; Kanno, Taro; Shirato, Midori; Meirelles, Luiz; Sasaki, Keiichi; Niwano, Yoshimi

    2013-01-01

    The in vitro antibacterial activity of the hydroxyl radical generation system by the photolysis of H2O2 in combination with proanthocyanidin, which refers to a group of polyphenolic compounds, was examined. Bactericidal activity of photo-irradiated H2O2 at 405 nm against Streptococcus mutans, a major pathogen of dental caries, was augmented in the presence of proanthocyanidin, whose bactericidal effect by itself was very poor, in a concentration-dependent manner. This combination was also proven effective against Porphyromonas gingivalis, a major pathogen of periodontitis. It is speculated that H2O2, generated from photo-irradiated proanthocyanidin around the bacterial cells, is photolyzed to the hydroxyl radical, which would in turn affect the membrane structure and function of the bacterial cells, resulting in augmented sensitivity of bacterial cells to the disinfection system utilizing the photolysis of H2O2. The present study suggests that the combination of H2O2 and proanthocyanidin works synergistically to kill bacteria when photo-irradiated.

  3. [Bacteriostatic and bactericidal activities of cyclines, macrolides and fluoroquinolones against Chlamydia trachomatis].

    Science.gov (United States)

    Dailloux, M; Villemain, P

    1992-05-01

    The in vitro activity of minocycline, doxycycline, erythromycin, roxithromycin, spiramycin, pefloxacin, and ofloxacin against ten C. trachomatis strains recovered from human genital tract specimens was evaluated. Mac Coy cell monolayers in 24-microwell plates were used. The C. trachomatis inoculum was 10(4) IFU/well. Appropriate dilutions of antibiotic were added and inclusions were detected by immunofluorescence using monoclonal antibodies. MICs were determined after 48 hours of exposure to each antimicrobial. The MIC90 for cyclines was 0.2 mg/l. Among tested macrolides, roxithromycin had a lower MIC than erythromycin (0.2 versus 0.4 mg/l) whereas spiramycin inhibited growth only in a concentration of 2 mg/l. Ofloxacin showed better activity than pefloxacin. Bactericidal activity was evaluated by determining two parameters: MBC1 (without transfer to new cells) measured the ability of a C. trachomatis particle to persist in a latent form within cells exposed to an antibiotic and to grow again following removal of the antibiotic, whereas MBC2 (with transfer to new cells) reflected infectivity of the bacteria after 48 hours exposure to the antimicrobial. None of the tested antibiotics was bactericidal according to both parameters. The ability of C. trachomatis to remain within antibiotic-exposed cells in a latent form was clearly demonstrated by the high MBC1 values. This feature may explain why recurrences are common in clinical practice.

  4. Encapsulation of titanium dioxide nanoparticles in PLA microspheres using supercritical emulsion extraction to produce bactericidal nanocomposites

    Science.gov (United States)

    Campardelli, R.; Della Porta, G.; Gomez, V.; Irusta, S.; Reverchon, E.; Santamaria, J.

    2013-10-01

    In this work, PLA microparticles containing TiO2 (anatase) nanoparticles have been produced using the Continuous Supercritical Emulsion Extraction technique (SEE-C). A stabilized anatase colloidal suspension (15 ± 5 nm) in ethanol aqueous solution was obtained by precipitation from solutions of titanium alkoxides and directly used as the water internal phase of a water-in-oil in water double emulsion or suspended as a powder in the organic phase of a solid-in-oil in water emulsion. Micro- (0.9 ± 0.5 μm) and submicro-particles (203 ± 40 nm) have been produced, with TiO2 nominal loadings of 1.2, 2.4, and 3.6 wt%. High TiO2 encapsulation efficiencies up to about 90 % have been obtained. PLA/TiO2 particles have been characterized by TEM and XPS to investigate the dispersion of the metal oxide in the polymeric matrix. The photo-assisted bactericidal activity of TiO2-containing microparticles against a biofilm-forming strain of Staphylococcus aureus was investigated in specific assays under UV light. Pure TiO2 nanoparticles and PLA/TiO2 particles showed the same bactericidal activity.

  5. An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.

    Directory of Open Access Journals (Sweden)

    Clifford E. Starliper

    2015-01-01

    Full Text Available Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC’s were determined for these four oils, Allimed® (garlic extract, Allium sativum and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02–0.04% were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5% of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate.

  6. Synthesis and evaluation of bactericidal properties of CuO nanoparticles against Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    Sayedeh Fatemeh Shaffiey

    2014-04-01

    Full Text Available   Objective(s: CuO is one of the most important transition metal oxides due to its captivating properties. It is used in various technological applications such as high critical temperature superconductors, gas sensors, in photoconductive applications, and so on. Recently, it has been used as an antimicrobial agent against various bacterial species.   Materials and Methods: Here, we synthesized CuO nanoparticles (NPs and explored the antibacterial activity of CuO NPs preparation. Results: Single crystalline nanoparticles of copper oxide having almost uniform particle size of 5-6 nm has been synthesized by a facile and versatile route. XRD spectra confirmed the formation of single phase CuO NPs. Transmission electron microscopy results corroborate well with XRD results. The technique employed is free from toxic solvents, organics and amines, is based on a simple reaction of copper sulfate and de-ionized water (DI, and their bactericidal effects against of Aeromonas hydrophila ATCC 7966T bacteria were investigated. Minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC with liquid culture for all of the Aeromonas hydrophila culture Medias was done. Conclusion: Present study confirms that Copper oxide nanoparticles have great promise as antimicrobial agent against Aeromonas hydrophila

  7. Green Synthesis of Silver Nanoparticles and Their Bactericidal and Antimycotic Activities against Oral Microbes

    Directory of Open Access Journals (Sweden)

    Osvelia E. Rodríguez-Luis

    2016-01-01

    Full Text Available Nanotechnology is a new discipline with huge applications including medicine and pharmacology industries. Although several methods and reducing agents have been employed to synthesize silver nanoparticles, reactive chemicals promote toxicity and nondesired effects on the human and biological systems. The objective of this work was to synthesize silver nanoparticles from Glycyrrhiza glabra and Amphipterygium adstringens extracts and determine their bactericidal and antimycotic activities against Enterococcus faecalis and Candida albicans growth, respectively. 1 and 10 mM silver nitrate were mixed with an extract of Glycyrrhiza glabra and Amphipterygium adstringens. Green silver nanoparticles (AgNPs were characterized by TEM, Vis-NIR, FTIR, fluorescence, DLS, TGA, and X-ray diffraction (XRD analysis. Bactericidal and antimycotic activities of AgNPs were determined by Kirby and Bauer method and cell viability MTT assays. AgNPs showed a spherical shape and average size of 9 nm if prepared with Glycyrrhiza glabra extract and 3 nm if prepared with Amphipterygium adstringens extract. AgNPs inhibited the bacterial and fungal growth as was expected, without a significant cytotoxic effect on human epithelial cells. Altogether, these results strongly suggest that AgNPs could be an interesting option to control oral biofilms.

  8. Plasma bactericidal/permeability-increasing protein concentrations in critically ill children with the sepsis syndrome.

    Science.gov (United States)

    Wong, H R; Doughty, L A; Wedel, N; White, M; Nelson, B J; Havrilla, N; Carcillo, J A

    1995-12-01

    Bactericidal/permeability-increasing protein (BPI) is a neutrophil azurophilic granule component that is bactericidal towards Gram-negative bacteria and inhibits lipopolysaccharide-mediated inflammatory responses. We conducted a prospective study to measure plasma BPI concentrations in 36 critically ill children with and without the sepsis syndrome. Plasma BPI concentrations ranged from 0.5 to 452 ng/ml. Patients with the sepsis syndrome had higher median plasma BPI concentrations than critically ill controls (5.1 vs. 1.8 ng/ml, P = 0.006). Patients with organ system failure had higher median plasma BPI concentrations than those with no organ system failure (4.5 vs. 1.3 ng/ml, P = 0.001). Plasma BPI concentrations were positively associated with pediatric risk of mortality score (P = 0.03, rs = 0.4). These data provide the first clinical insights regarding the role of endogenous BPI production in critically ill children and suggest that BPI may play an important role in host defenses.

  9. [Treatment of osteomyelitis with oral bactericidal antibiotics-- description of 9 cases].

    Science.gov (United States)

    Major, S; Chuard, C; Regamey, C

    1996-01-27

    The efficacy of oral bactericidal antibiotics in the treatment of osteomyelitis is analyzed retrospectively by a review of 9 cases histories. The first patient was treated in 1982. Clinical and laboratory controls were reviewed up to 1.1.1995. In 6 patients S. aureus was isolated, while in 3 patients the organism could not be cultured but gram + cocci were almost likely. 5 cases of osteomyelitis were acute, 4 were chronic and in one case there was an infection of an artificial knee prothesis. The isolated S. aureus were sensitive to the antibiotics prescribed. 8 patients received a combination of flucloxacillin (2-4 g/day) and rifampicin (600 mg/day); one patient was treated with the combination amoxicillin/clavulanic acid (1500/425 mg/day) followed by ofloxacin (400 mg/day) and finally co-trimoxazole (320/1600 mg/day). 3 patients received all antibiotics orally; in 6 patients oral administration followed a short intravenous course of the antibiotic combination. The duration of treatment varied between 6 and 23 weeks. Follow-up extended over 9 months (n = 1), 14 months (n = 3), 4-7 years (n = 3), and 10-12 years (n = 2). In 8 cases the osteomyelitis was cured (89%). In our view, a combination of bactericidal oral antibiotics with good penetration into bone tissue can be prescribed in selected cases of osteomyelitis to shorten or even avoid the standard intravenous therapy of acute or chronic diseases.

  10. Serum bactericidal activity from intravenous ciprofloxacin and azlocillin given alone and in combination to healthy subjects.

    Science.gov (United States)

    Orlando, P L; Barriere, S L; Hindler, J A; Frost, R W

    1990-01-01

    Ciprofloxacin plus azlocillin have been shown to exhibit in vitro synergy versus a variety of organisms, including Pseudomonas aeruginosa. This study examined this interaction in vivo, testing serum bactericidal activity (SBA) in six healthy male subjects after intravenous administration of ciprofloxacin 4 mg/kg (C), azlocillin 60 mg/kg (A), and the two simultaneously (C/A). Eight different organisms were tested: four isolates of P. aeruginosa with varying susceptibilities to C and A, and one isolate each of Escherichia coli (EC), Staphylococcus aureus (SA) Serratia marcescens (SM), and Klebsiella pneumoniae (KP), all of which were susceptible to both drugs. Blood samples were collected at the end of 30-min infusions and at 4 and 8 hr. Reciprocal titers were plotted versus time and area under the bactericidal titer curve (AUBC) calculated to assess antibacterial interactions. Results indicated that P. aeruginosa-1 (PA-1), EC, and KP were synergistically killed by C/A. AUBC for PA-1 were C = 36, A = 11, C/A = 144, p less than 0.05. AUBC for EC were C = 1059, A = 180, C/A = 1504, p = 0.05. AUBC for KP were C = 327, A = 97, C/A = 584, p = 005. Additive effects were demonstrated versus all of the other organisms except Serratia marcescens, where an indifferent effect was observed. Ciprofloxacin plus azlocillin may be a useful combination of the treatment of selected Gram-negative bacillary infections.

  11. Encapsulation of titanium dioxide nanoparticles in PLA microspheres using supercritical emulsion extraction to produce bactericidal nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Campardelli, R., E-mail: rcampardelli@unisa.it; Della Porta, G. [University of Salerno, Department of Industrial Engineering (Italy); Gomez, V.; Irusta, S. [University of Zaragoza, Aragon Institute of Nanoscience (INA) (Spain); Reverchon, E., E-mail: ereverchon@unisa.it [University of Salerno, Department of Industrial Engineering (Italy); Santamaria, J., E-mail: jesus.santamaria@unizar.es [University of Zaragoza, Aragon Institute of Nanoscience (INA) (Spain)

    2013-10-15

    In this work, PLA microparticles containing TiO{sub 2} (anatase) nanoparticles have been produced using the Continuous Supercritical Emulsion Extraction technique (SEE-C). A stabilized anatase colloidal suspension (15 {+-} 5 nm) in ethanol aqueous solution was obtained by precipitation from solutions of titanium alkoxides and directly used as the water internal phase of a water-in-oil in water double emulsion or suspended as a powder in the organic phase of a solid-in-oil in water emulsion. Micro- (0.9 {+-} 0.5 {mu}m) and submicro-particles (203 {+-} 40 nm) have been produced, with TiO{sub 2} nominal loadings of 1.2, 2.4, and 3.6 wt%. High TiO{sub 2} encapsulation efficiencies up to about 90 % have been obtained. PLA/TiO{sub 2} particles have been characterized by TEM and XPS to investigate the dispersion of the metal oxide in the polymeric matrix. The photo-assisted bactericidal activity of TiO{sub 2}-containing microparticles against a biofilm-forming strain of Staphylococcus aureus was investigated in specific assays under UV light. Pure TiO{sub 2} nanoparticles and PLA/TiO{sub 2} particles showed the same bactericidal activity.

  12. Surface characterization of electrodeposited silver on activated carbon for bactericidal purposes.

    Science.gov (United States)

    Ortiz-Ibarra, Hector; Casillas, Norberto; Soto, Victor; Barcena-Soto, Maximiliano; Torres-Vitela, Refugio; de la Cruz, Wencel; Gómez-Salazar, Sergio

    2007-10-15

    The use of an electrochemical reactor operated under different flow conditions to deposit silver from aqueous AgNO(3) solutions and tartaric acid as an organic additive on a commercial activated carbon with ultimate bactericidal applications in water purification processes is presented. The characterization of carbon/silver samples was studied by BET, FTIR, X-ray diffraction, XPS, and SEM techniques. The bactericidal activity of the carbon/silver samples was tested on drinking water samples inoculated with E. coli. A reduction of carbon surface area was detected and was caused by increased amounts of silver deposited on carbon samples. Adherent silver deposits were obtained on the carbon/silver samples. X-ray diffraction studies of carbon with electrodeposited silver showed two different preferential deposition planes, [111] and [220]. The FTIR results confirm the presence of carboxyl, phenolic, quinone, and ether surface groups. The XPS results suggest the formation of Ag(2)O and AgO surface species and confirm the reduction of silver to the metallic form. Antimicrobial activity toward E. coli indicated reductions by up to 7 orders of magnitude in the log CFU/mL in just 10 min contact time and for silver contents of 2.47 wt%.

  13. Inhibitory and bactericidal action of the biocorrosion agents «INCORGAS» and «AMDOR».

    Science.gov (United States)

    Tsygankova, L E; Vigdorovich, V I; Esina, M N; Nazina, T N; Dubinskaya, E V

    2014-06-01

    Inhibiting action of A, B and M-X compositions against hydrosulfide corrosion of carbon steel, hydrogen diffusion through the steel membrane has been studied along with their bactericidal effect with respect to sulfate-reducing bacteria of Desulfomicrobium type. Bactericidal properties of the compositions have been studied in the Postgate medium. Corrosion tests have been made in the NACE medium saturated by hydrogen sulfide and carbon dioxide separately and together by methods of gravimetrical measurements and linear polarization resistance (LRP). Potentiodynamic polarization and electrochemical diffusion method have been used. Steel protection is determined in the inhibited solutions by combined action of corrosion products film and inhibitor. Presence of sulfate-reducing bacteria in medium increases hydrogen diffusion flux through the steel membrane by 2-3 times and essentially stimulates effect of the inhibitors. The inhibiting compositions decrease quantity of sulfate-reducing bacteria (SRB) by 95-98%. The obtained results testify about predominately bacteriostatic action of the inhibiting compositions, which has influence on the enzymatic systems of SRB cells responsible directly for the sulfate reduction because of substantially decreasing the biogenic hydrogen sulfide concentration in the system.

  14. Pseudomonas aeruginosa bacteriophage PA1Ø requires type IV pili for infection and shows broad bactericidal and biofilm removal activities.

    Science.gov (United States)

    Kim, Shukho; Rahman, Marzia; Seol, Sung Yong; Yoon, Sang Sun; Kim, Jungmin

    2012-09-01

    We isolated a new lytic Pseudomonas aeruginosa phage that requires type IV pili for infection. PA1Ø has a broad bactericidal spectrum, covering Gram-positive and Gram-negative bacteria, and can eradicate biofilm cells. PA1Ø may be developed as a therapeutic agent for biofilm-related mixed infections with P. aeruginosa and Staphylococcus aureus.

  15. Delayed bactericidal response of Mycobacterium tuberculosis to bedaquiline involves remodelling of bacterial metabolism

    DEFF Research Database (Denmark)

    Koul, A.; Vranckx, L.; Dhar, N.;

    2014-01-01

    microfluidic devices and time-lapse microscopy of Mycobacterium tuberculosis, we confirm the absence of significant bacteriolytic activity during the first 3-4 days of exposure to BDQ. BDQ-induced inhibition of ATP synthesis leads to bacteriostasis within hours after drug addition. Transcriptional......Bedaquiline (BDQ), an ATP synthase inhibitor, is the first drug to be approved for treatment of multidrug-resistant tuberculosis in decades. Though BDQ has shown excellent efficacy in clinical trials, its early bactericidal activity during the first week of chemotherapy is minimal. Here, using...... and proteomic analyses reveal that M. tuberculosis responds to BDQ by induction of the dormancy regulon and activation of ATP-generating pathways, thereby maintaining bacterial viability during initial drug exposure. BDQ-induced bacterial killing is significantly enhanced when the mycobacteria are grown on non...

  16. Calcium and zinc containing bactericidal glass coatings for biomedical metallic substrates.

    Science.gov (United States)

    Esteban-Tejeda, Leticia; Díaz, Luis A; Prado, Catuxa; Cabal, Belén; Torrecillas, Ramón; Moya, José S

    2014-07-23

    The present work presents new bactericidal coatings, based on two families of non-toxic, antimicrobial glasses belonging to B2O3-SiO2-Na2O-ZnO and SiO2-Na2O-Al2O3-CaO-B2O3 systems. Free of cracking, single layer direct coatings on different biomedical metallic substrates (titanium alloy, Nb, Ta, and stainless steel) have been developed. Thermal expansion mismatch was adjusted by changing glass composition of the glass type, as well as the firing atmosphere (air or Ar) according to the biomedical metallic substrates. Formation of bubbles in some of the glassy coatings has been rationalized considering the reactions that take place at the different metal/coating interfaces. All the obtained coatings were proven to be strongly antibacterial versus Escherichia coli (>4 log).

  17. Calcium and Zinc Containing Bactericidal Glass Coatings for Biomedical Metallic Substrates

    Directory of Open Access Journals (Sweden)

    Leticia Esteban-Tejeda

    2014-07-01

    Full Text Available The present work presents new bactericidal coatings, based on two families of non-toxic, antimicrobial glasses belonging to B2O3–SiO2–Na2O–ZnO and SiO2–Na2O–Al2O3–CaO–B2O3 systems. Free of cracking, single layer direct coatings on different biomedical metallic substrates (titanium alloy, Nb, Ta, and stainless steel have been developed. Thermal expansion mismatch was adjusted by changing glass composition of the glass type, as well as the firing atmosphere (air or Ar according to the biomedical metallic substrates. Formation of bubbles in some of the glassy coatings has been rationalized considering the reactions that take place at the different metal/coating interfaces. All the obtained coatings were proven to be strongly antibacterial versus Escherichia coli (>4 log.

  18. Synthesis of nanosilver particles by reverse micelle method and study of their bactericidal properties

    Science.gov (United States)

    Dung, Tran Thi Ngoc; Buu, Ngo Quoc; Viet Quang, Dang; Thi Ha, Huynh; Bang, Le Anh; Hoai Chau, Nguyen; Thi Ly, Nguyen; Trung, Nguyen Vu

    2009-09-01

    Nanosilver particles have been synthesized by the reverse micelle method, where AgNO3 was used as a silver ions source, NaBH4 and quercetin - as reducing agents, CTAB, SDOSS and AOT- as surfactants, while the stabilizer was Vietnamese chitosan. Studying the factors influencing the process of nanosilver particle formation, it was shown that the particle size of the nanosilver products depends on the concentration of the reaction components and their stoichiometric ratio. It was also shown that the reaction system using AOT surfactant is capable of producing nanosilver particles with smallest nanoparticles (phiav ~ 5 nm) and good particle-size distribution. The study on bactericidal activity of the nanosilver products indicated that the disinfecting solution with a nanosilver concentration of 3 ppm was able to inhibit all E.coli and Coliforms, TPC and fungi at 15 ppm, while Vibrio cholerae cells were inactivated completely with 0.5 ppm of nanosilver after 30 minutes exposition.

  19. A study of bactericidal effect and optimization of pathogenic bacteria using TiO2 photocatalyst.

    Science.gov (United States)

    Kim, Tae-Young; Park, Seung-Shik; Kim, Seung-Jai; Cho, Sung-Young

    2011-02-01

    The photocatalytic degradation of Salmonella choleraesuis subsp. and Vibrio parahaemolyticus in water by TiO2 catalysts was investigated in a batch reactor. After 30 min of irradiation with UV light in the presence of 1 mg/ml of TiO2, death ratio of S. choleraesuis subsp. and V. parahaemolyticus was 60% and 83%, respectively. And complete killing of the cells was achieved after 3 h of illumination in the presence of TiO2. We established the response surface methodology to investigate the effect of principal parameters on the pathogenic bacteria sterilization such as TiO2 concentration, pH and temperature. By applying response surface analysis to the bactericidal effect of S. almonella choleraesuis subsp. and V. parahaemolyticus, we found that the cell death ratio was influenced significantly by the first order term of TiO2 concentration.

  20. A Kunitz proteinase inhibitor from corms of Xanthosoma blandum with bactericidal activity.

    Science.gov (United States)

    Lima, Thaís B; Silva, Osmar N; Migliolo, Ludovico; Souza-Filho, Carlos R; Gonçalves, Eduardo G; Vasconcelos, Ilka M; Oliveira, José T A; Amaral, André C; Franco, Octávio L

    2011-05-27

    Bacterial infections directly affect the world's population, and this situation has been aggravated by indiscriminate use of antimicrobial agents, which can generate resistant microorganisms. In this report, an initial screening of proteins with antibacterial activity from corms of 15 species of the Xanthosoma genus was conducted. Since Xanthosoma blandum corms showed enhanced activity toward bacteria, a novel protein with bactericidal activity was isolated from this particular species. Edman degradation was used for protein N-termini determination; the primary structure showed similarities with Kunitz inhibitors, and this protein was named Xb-KTI. This protein was further challenged against serine proteinases from different sources, showing clear inhibitory activities. Otherwise, no hemolytic activity was observed for Xb-KTI. The results demonstrate the biotechnological potential of Xb-KTI, the first proteinase inhibitor with antimicrobial activity described in the Xanthosoma genus.

  1. Effect of increased CRM₁₉₇ carrier protein dose on meningococcal C bactericidal antibody response.

    Science.gov (United States)

    Lee, Lucia H; Blake, Milan S

    2012-04-01

    New multivalent CRM(197)-based conjugate vaccines are available for childhood immunization. Clinical studies were reviewed to assess meningococcal group C (MenC) antibody responses following MenC-CRM(197) coadministration with CRM(197)-based pneumococcal or Haemophilus influenzae type b conjugate vaccines. Infants receiving a total CRM(197) carrier protein dose of ∼50 μg and concomitant diphtheria-tetanus-acellular pertussis (DTaP)-containing vaccine tended to have lower MenC geometric mean antibody titers and continued to have low titers after the toddler dose. Nevertheless, at least 95% of children in the reported studies achieved a MenC serum bactericidal antibody (SBA) titer of ≥ 1:8 after the last infant or toddler dose. SBA was measured using an assay with a baby rabbit or human complement source. Additional studies are needed to assess long-term antibody persistence and MenC CRM(197) conjugate vaccine immunogenicity using alternative dosing schedules.

  2. Ability of Staphylococcus aureus coagulase genotypes to resist neutrophil bactericidal activity and phagocytosis

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Scott, N. L.; Sordillo, L. M.

    1994-01-01

    genotype. The interaction between bacteria and neutrophils was measured by phagocytosis and bactericidal effect. The average percent killing of bacteria was lowest (40.0%) with strains belonging to the most common genotype, medium (50%) with strains belonging to the intermediate type, and highest (64......; rare type, 10.5/cell). These findings suggest that one of the reasons for the variation in prevalence of different genotypes of S. aureus in the mammary gland is due to the superior ability of some types to resist phagocytosis and/or killing by bovine neutrophils......This study investigated the functional capabilities of neutrophils against different Staphylococcus aureus genotypes isolated from cows with mastitis. Six strains of S. aureus were chosen for use in the study, two with a common genotype, two with an intermediate genotype, and two with a rare...

  3. Synthesis of poly(amidoamine-dendrimer-silver nanoparticles composite for application as bactericides

    Directory of Open Access Journals (Sweden)

    Shahla Namazkar

    2014-04-01

    Full Text Available As awareness of sanitation, disease transmission factors and personal protection increases, researchers have focused on developing materials with antibacterial properties. Silver-PAMAM-dendrimer has unique antibacterial properties that make it an ideal candidate for medical applications. In this study, poly (amidoamine (PAMAM dendrimers from Generations 0.5- 4.0 were synthesized using divergent methods. Silver was combined with PAMAM dendrimers from the Generation 2.0, 3.0 and 4.0 to form colloidal solutions. The antimicrobial capabilities of Silver-PAMAM-dendrimer (Generation 2.0 were tested against four types of gram positive and negative bacteria. Its bactericidal activities were revealed for all four types of bacteria that could not grow in samples containing 600 ppm of Silver-PAMAM-dendrimer (Generation 2.0.

  4. The Vibrational Spectra of Bactericide molecules: Terahertz Spectroscopy and Density Functional Theory Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaowei; Wang Qiang, E-mail: qiangwang@cjlu.edu.cn [Department of Quality and Safety Engineering, China Jiliang University, Hangzhou, 310018 (China)

    2011-02-01

    In the room temperature and nitrogen conditions, we presented well-resolved absorption spectra and indexes of refraction of bactericide molecules in the far infrared radiation (FIR) spectral region recorded by terahertz time-domain spectroscopy (THz-TDS). As illustrative examples we discussed the absorption spectra of captan and folpet in THz region. The absorption coefficient and index of refraction of them were obtained. Meanwhile, density functional theory (DFT) with software package Gaussian 03 using B3LYP theory was employed for optimization and vibration analysis. With the help of Gaussian View 3.09, the distinct absorption peaks of those molecules were assigned with reliable accuracy. They were caused by intermolecular hydrogen-bonding, molecular torsion or vibration modes, absorption of water molecules, etc. As the absorption spectra are highly sensitive to the overall structure and configuration of the molecules, the THz-TDS procedure can provide a direct fingerprint of the molecular structure or conformational state of a compound.

  5. Modification of medical grade PVC with N-vinylimidazole to obtain bactericidal surface

    Science.gov (United States)

    Meléndez-Ortiz, H. Iván; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Jiménez-Páez, Víctor M.; Bucio, Emilio

    2016-02-01

    N-vinylimidazole (VIm) was grafted onto medical-grade poly(vinyl chloride) (PVC) catheters in order to provide a bactericidal surface that make them less susceptible to microbial colonization. The grafting of VIm was carried out by means of gamma rays using the direct method, which demonstrated to be an efficient and fast procedure for obtaining PVC-g-VIm copolymers. These copolymers could be quaternized in a second step using methyl iodide (CH3I). The effects of solvent nature, absorbed dose, and monomer concentration on the grafting yield were investigated. Modified PVC catheters were characterized by means of Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and swelling studies. PVC-g-VIm copolymers both before and after quaternization showed good hemocompatibility, while quaternization was required to inhibit the growth of Staphylococcus aureus.

  6. Preparation of bactericidal cationic PDMS surfaces using a facile and efficient approach

    Science.gov (United States)

    Kébir, Nasreddine; Kriegel, Irène; Estève, Marc; Semetey, Vincent

    2016-01-01

    Two cationic polymers containing vinyl and quaternary ammonium groups were successfully grafted on silicone surfaces containing Sisbnd H groups. The reaction was carried out by straightforward hydrosilylation reaction in water without using exogenous catalyst and without doping the surface with Sisbnd H groups. The Sisbnd H content was varied by changing the curing time or the ratio between silicone components. The surfaces obtained exhibited quaternary ammonium densities ranging from 1.8 ÿ 1014 to 2.8 ÿ 1015 charge/cm2 and higher polarity and hydrophilicity in comparison with non grafted surfaces. Bactericidal effects of these surfaces against Escherichia coli and Staphylococcus epidermidis were evidenced. This study have evidenced also the fouling of the poly(quaternary ammonium) (PQA) surfaces by contact with plasmatic proteins probably limiting their use in some biomedical field (e.g. implantable medical devices).

  7. Dysfunctional CFTR alters the bactericidal activity of human macrophages against Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Paola Del Porto

    Full Text Available Chronic inflammation of the lung, as a consequence of persistent bacterial infections by several opportunistic pathogens represents the main cause of mortality and morbidity in cystic fibrosis (CF patients. Mechanisms leading to increased susceptibility to bacterial infections in CF are not completely known, although the involvement of cystic fibrosis transmembrane conductance regulator (CFTR in microbicidal functions of macrophages is emerging. Tissue macrophages differentiate in situ from infiltrating monocytes, additionally, mature macrophages from different tissues, although having a number of common activities, exhibit variation in some molecular and cellular functions. In order to highlight possible intrinsic macrophage defects due to CFTR dysfunction, we have focused our attention on in vitro differentiated macrophages from human peripheral blood monocytes. Here we report on the contribution of CFTR in the bactericidal activity against Pseudomonas aeruginosa of monocyte derived human macrophages. At first, by real time PCR, immunofluorescence and patch clamp recordings we demonstrated that CFTR is expressed and is mainly localized to surface plasma membranes of human monocyte derived macrophages (MDM where it acts as a cAMP-dependent chloride channel. Next, we evaluated the bactericidal activity of P. aeruginosa infected macrophages from healthy donors and CF patients by antibiotic protection assays. Our results demonstrate that control and CF macrophages do not differ in the phagocytic activity when infected with P. aeruginosa. Rather, although a reduction of intracellular live bacteria was detected in both non-CF and CF cells, the percentage of surviving bacteria was significantly higher in CF cells. These findings further support the role of CFTR in the fundamental functions of innate immune cells including eradication of bacterial infections by macrophages.

  8. A shape memory foam composite with enhanced fluid uptake and bactericidal properties as a hemostatic agent.

    Science.gov (United States)

    Landsman, T L; Touchet, T; Hasan, S M; Smith, C; Russell, B; Rivera, J; Maitland, D J; Cosgriff-Hernandez, E

    2017-01-01

    Uncontrolled hemorrhage accounts for more than 30% of trauma deaths worldwide. Current hemostatic devices focus primarily on time to hemostasis, but prevention of bacterial infection is also critical for improving survival rates. In this study, we sought to improve on current devices used for hemorrhage control by combining the large volume-filling capabilities and rapid clotting of shape memory polymer (SMP) foams with the swelling capacity of hydrogels. In addition, a hydrogel composition was selected that readily complexes with elemental iodine to impart bactericidal properties to the device. The focus of this work was to verify that the advantages of each respective material (SMP foam and hydrogel) are retained when combined in a composite device. The iodine-doped hydrogel demonstrated an 80% reduction in bacteria viability when cultured with a high bioburden of Staphylococcus aureus. Hydrogel coating of the SMP foam increased fluid uptake by 19× over the uncoated SMP foam. The composite device retained the shape memory behavior of the foam with more than 15× volume expansion after being submerged in 37°C water for 15 min. Finally, the expansion force of the composite was tested to assess potential tissue damage within the wound during device expansion. Expansion forces did not exceed 0.6N, making tissue damage during device expansion unlikely, even when the expanded device diameter is substantially larger than the target wound site. Overall, the enhanced fluid uptake and bactericidal properties of the shape memory foam composite indicate its strong potential as a hemostatic agent to treat non-compressible wounds.

  9. Approaches for Controlled Ag(+) Ion Release: Influence of Surface Topography, Roughness, and Bactericide Content.

    Science.gov (United States)

    Sukhorukova, I V; Sheveyko, A N; Shvindina, N V; Denisenko, E A; Ignatov, S G; Shtansky, D V

    2017-02-01

    Silver is the most famous bactericidal element known from ancient times. Its antibacterial and antifungal effects are typically associated with the Ag ionization and concentration of Ag(+) ions in a bacterial culture. Herein we thoroughly studied the influence of surface topography and roughness on the rate of Ag(+) ion release. We considered two types of biocompatible and bioactive TiCaPCON-Ag films with 1 and 2 at. % of Ag and nine types of Ti surfaces with an average roughness varying in the range from 5.4 × 10(-2) to 12.6 μm and different topographic features obtained through polishing, sandblasting, laser treatment, and pulsed electrospark deposition. It is demonstrated that the Ag(+) ion release rates do not depend on the Ag content in the films as the main parameter, and it is other factors, such as the state of Ag agglomeration, surface topography and roughness, as well as kinetics of surface oxidation, that play a critical role. The obtained results clearly show a synergistic effect of the Ag content in the film and surface topography and roughness on Ag(+) ion release. By changing the surface topographical features at a constant content of bactericidal element, we showed that the Ag(+) ion release can be either accelerated by 2.5 times or almost completely suppressed. Despite low Ag(+) ion concentration in physiological solution (<40 ppb), samples with specially fabricated surface reliefs (flakes or holes) showed a pronounced antibacterial effect already after 3 h of immersion in E. coli bacterial culture. Thus, our results open up new possibilities for the production of cost-effective, scalable, and biologically safe implants with pronounced antibacterial characteristics for future applications in the orthopedic field.

  10. Drug delivery property, bactericidal property and cytocompatibility of magnetic mesoporous bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yi-Zhuo [The Education Ministry Key Lab of Resource Chemistry, Shanghai Normal University, Shanghai 200234 (China); Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Li, Yang [Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Yu, Xi-Bin [The Education Ministry Key Lab of Resource Chemistry, Shanghai Normal University, Shanghai 200234 (China); Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Liu, Li-Na [Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Zhu, Zhen-An, E-mail: zhuzhenan2006@126.com [Shanghai Key Laboratory of Orthopedic Implant, Department of Orthopedic Surgery, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Guo, Ya-Ping, E-mail: ypguo@shnu.edu.cn [The Education Ministry Key Lab of Resource Chemistry, Shanghai Normal University, Shanghai 200234 (China); Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China)

    2014-08-01

    A multifunctional magnetic mesoporous bioactive glass (MMBG) has been widely used for a drug delivery system, but its biological properties have been rarely reported. Herein, the effects of mesopores and Fe{sub 3}O{sub 4} nanoparticles on drug loading–release property, bactericidal property and biocompatibility have been investigated by using mesoporous bioactive glass (MBG) and non-mesoporous bioactive glass (NBG) as control samples. Both MMBG and MBG have better drug loading efficiency than NBG because they possess ordered mesoporous channels, big specific surface areas and high pore volumes. As compared with MBG, the Fe{sub 3}O{sub 4} nanoparticles in MMBG not only provide magnetic property, but also improve sustained drug release property. For gentamicin-loaded MMBG (Gent-MMBG), the sustained release of gentamicin and the Fe{sub 3}O{sub 4} nanoparticles minimize bacterial adhesion significantly and prevent biofilm formation against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). Moreover, the magnetic Fe{sub 3}O{sub 4} nanoparticles in MMBG can promote crucial cell functions such as cell adhesion, spreading and proliferation. The excellent biocompatibility and drug delivery property of MMBG suggest that Gent-MMBG has great potentials for treatment of implant-associated infections. - Highlights: • Multifunctional magnetic mesoporous bioactive glass is fabricated. • The bioactive glass has great biocompatibility. • The bioactive glass exhibits high drug loading–release properties. • The drug delivery system has bactericidal property. • Magnetic particles improve cell adhesion, spreading and proliferation.

  11. Session 6: Bactericidal indoor air decontamination on TiO{sub 2}-based photo-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Keller, V.; Keller, N.; Garin, F. [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), 67 - Strasbourg (France); Lett, M.C. [Laboratoire d' Expression des Genomes et de Microorganismes (LGM), 67 - Strasbourg (France)

    2004-07-01

    The innovative approach of our work is focused on the indoor air decontamination on TiO{sub 2}-based photo-catalysts for applications in places with high infection and contamination risks, such as hospitals, collectivities or even for domestic use. The bactericidal activity of a series of photo-catalysts is evaluated for the Escherichia coli (typical dimensions of 1 x 4 {mu}m) photo-killing on: (i) commercial TiO{sub 2} P25 (Degussa), (ii) TiO{sub 2} prepared by sol-gel methods and (iii) chemically and electronically modified TiO{sub 2}, such as binary and ternary coupled semiconductor systems, WO{sub 3}/TiO{sub 2}, WO{sub 3}-{beta}-SiC, WO{sub 3}/TiO{sub 2}-{beta}-SiC. The second innovation concerns the especially built bio-photo-catalytic device, made of a bacteria-supplying continuous system coupled to a photo-reactor. The survival ratio and physiological states of bacteria have been determined as a function of time on stream on the series of photo-catalysts given previously, by measurement of cellular ATP or by viability staining. Morphology of dead bacteria was also investigated by electronic microscopy. The evolution of the survival ratio of the bacteria with time on stream will be presented in details. The kinetic of photo-killing rate in function of UV intensity, of photo-catalyst content and on the 'bacteria flow rate and concentration' will be discussed in details. A possible mechanism of bactericidal effect through cell attack and destruction will be proposed. (authors)

  12. Disparity between timed-kill and checkerboard methods for determination of in vitro bactericidal interactions of vancomycin plus rifampin versus methicillin-susceptible and -resistant Staphylococcus aureus.

    Science.gov (United States)

    Bayer, A S; Morrison, J O

    1984-08-01

    The role of rifampin as an adjunctive agent to vancomycin in the therapy of serious systemic staphylococcal infections remains controversial. Several in vitro studies utilizing differing methodologies to define the bactericidal interactions of vancomycin plus rifampin versus Staphylococcus aureus have yielded markedly disparate results. The in vitro bactericidal synergistic activities of vancomycin plus rifampin were examined versus 48 clinical isolates of S. aureus, both methicillin susceptible and resistant. Each strain was tested simultaneously in timed-kill curve and checkerboard systems. By timed-kill curve, vancomycin plus rifampin usually had either an indifferent (67%) or synergistic (19 to 29%) effect, with a frequency dependent on sampling times; bactericidal antagonism was infrequently noted after 48 h of incubation (4%). Indifference was seen as a prevention of rifampin resistance by vancomycin. Synergy was more commonly noted at 48 than at 24 h of incubation. The bactericidal interaction results were similar for both methicillin-susceptible and -resistant strains. In contrast to the killing curve data, the checkerboard technique uniformly demonstrated bactericidal antagonism of vancomycin plus rifampin against all 48 staphylococci. We conclude that the nature of the in vitro bactericidal interactions of vancomycin plus rifampin against S. aureus is difficult to establish in vitro. This fact relates to the markedly disparate findings, which depended on both the synergy technique utilized and the test system conditions employed. In vivo studies are required to delineate the bactericidal interaction potentials of vancomycin plus rifampin versus S. aureus.

  13. Two approaches to form antibacterial surface: Doping with bactericidal element and drug loading

    Energy Technology Data Exchange (ETDEWEB)

    Sukhorukova, I.V.; Sheveyko, A.N.; Kiryukhantsev-Korneev, Ph.V. [National University of Science and Technology “MISIS”, Leninsky pr. 4, Moscow 119049 (Russian Federation); Anisimova, N.Y.; Gloushankova, N.A.; Zhitnyak, I.Y. [N.N Blokhin Russian Cancer Research Center of RAMS, Kashirskoe shosse 24, Moscow 115478 (Russian Federation); Benesova, J. [Institute of Experimental Medicine of the ASCR, Vídenska 1083, Prague 14220 (Czech Republic); Institute of Biophysics, 2nd Faculty of Medicine, Charles University in Prague, V Uvalu 84, Prague 15006 (Czech Republic); Amler, E. [Institute of Experimental Medicine of the ASCR, Vídenska 1083, Prague 14220 (Czech Republic); Faculty of Biomedical Engineering, Czech Technical University in Prague (Czech Republic); Shtansky, D.V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky pr. 4, Moscow 119049 (Russian Federation)

    2015-03-01

    Graphical abstract: - Highlights: • Bioactive materials with rate-controlled release of antibacterial agent. • Ag{sup +} ion release from TiCaPCON-Ag films depended on Ag content. • TiCaPCON-coated Ti network structure with blind pores loaded with co-amoxiclav. • Strong bactericidal effect of drug-loaded samples. • Antibacterial yet biocompatible and bioactive surfaces. - Abstract: Two approaches (surface doping with bactericidal element and loading of antibiotic into specially formed surface microcontainers) to the fabrication of antibacterial yet biocompatible and bioactive surfaces are described. A network structure with square-shaped blind pores of 2.6 ± 0.6 × 10{sup −3} mm{sup 3} for drug loading was obtained by selective laser sintering (SLS). The SLS-fabricated samples were loaded with 0.03, 0.3, 2.4, and 4 mg/cm{sup 2} of co-amoxiclav (amoxicillin and clavulanic acid). Ag-doped TiCaPCON films with 0.4, 1.2, and 4.0 at.% of Ag were obtained by co-sputtering of composite TiC{sub 0.5}-Ca{sub 3}(PO{sub 4}){sub 2} and metallic Ag targets. The surface structure of SLS-prepared samples and cross-sectional morphology of TiCaPCON-Ag films were studied by scanning electron microscopy. The through-thickness of Ag distribution in the TiCaPCON-Ag films was obtained by glow discharge optical emission spectroscopy. The kinetics of Ag ion release in normal saline solution was studied using inductively coupled plasma mass spectrometry. Bacterial activity of the samples was evaluated against S. epidermidis, S. aureus, and K. pneum. ozaenae using the agar diffusion test and photometric method by controlling the variation of optical density of the bacterial suspension over time. Cytocompatibility of the Ag-doped TiCaPCON films was observed in vitro using chondrocytic and MC3T3-E1 osteoblastic cells. The viability and proliferation of chondrocytic cells were determined using the MTS assay and PicoGreen assay tests, respectively. The alkaline phosphatase (ALP

  14. Bactericidal Immunity to Salmonella in Africans and Mechanisms Causing Its Failure in HIV Infection

    Science.gov (United States)

    Goh, Yun Shan; Necchi, Francesca; O’Shaughnessy, Colette M.; Micoli, Francesca; Gavini, Massimiliano; Young, Stephen P.; Msefula, Chisomo L.; Gondwe, Esther N.; Mandala, Wilson L.; Gordon, Melita A.; Saul, Allan J.; MacLennan, Calman A.

    2016-01-01

    Background Nontyphoidal strains of Salmonella are a leading cause of death among HIV-infected Africans. Antibody-induced complement-mediated killing protects healthy Africans against Salmonella, but increased levels of anti-lipopolysaccharide (LPS) antibodies in some HIV-infected African adults block this killing. The objective was to understand how these high levels of anti-LPS antibodies interfere with the killing of Salmonella. Methodology/Principal Findings Sera and affinity-purified antibodies from African HIV-infected adults that failed to kill invasive S. Typhimurium D23580 were compared to sera from HIV-uninfected and HIV-infected subjects with bactericidal activity. The failure of sera from certain HIV-infected subjects to kill Salmonella was found to be due to an inherent inhibitory effect of anti-LPS antibodies. This inhibition was concentration-dependent and strongly associated with IgA and IgG2 anti-LPS antibodies (p<0.0001 for both). IgG anti-LPS antibodies, from sera of HIV-infected individuals that inhibit killing at high concentration, induced killing when diluted. Conversely, IgG, from sera of HIV-uninfected adults that induce killing, inhibited killing when concentrated. IgM anti-LPS antibodies from all subjects also induced Salmonella killing. Finally, the inhibitory effect of high concentrations of anti-LPS antibodies is seen with IgM as well as IgG and IgA. No correlation was found between affinity or avidity, or complement deposition or consumption, and inhibition of killing. Conclusion/Significance IgG and IgM classes of anti-S. Typhimurium LPS antibodies from HIV-infected and HIV-uninfected individuals are bactericidal, while at very high concentrations, anti-LPS antibodies of all classes inhibit in vitro killing of Salmonella. This could be due to a variety of mechanisms relating to the poor ability of IgA and IgG2 to activate complement, and deposition of complement at sites where it cannot insert in the bacterial membrane. Vaccine trials

  15. Bactericidal Immunity to Salmonella in Africans and Mechanisms Causing Its Failure in HIV Infection.

    Directory of Open Access Journals (Sweden)

    Yun Shan Goh

    2016-04-01

    Full Text Available Nontyphoidal strains of Salmonella are a leading cause of death among HIV-infected Africans. Antibody-induced complement-mediated killing protects healthy Africans against Salmonella, but increased levels of anti-lipopolysaccharide (LPS antibodies in some HIV-infected African adults block this killing. The objective was to understand how these high levels of anti-LPS antibodies interfere with the killing of Salmonella.Sera and affinity-purified antibodies from African HIV-infected adults that failed to kill invasive S. Typhimurium D23580 were compared to sera from HIV-uninfected and HIV-infected subjects with bactericidal activity. The failure of sera from certain HIV-infected subjects to kill Salmonella was found to be due to an inherent inhibitory effect of anti-LPS antibodies. This inhibition was concentration-dependent and strongly associated with IgA and IgG2 anti-LPS antibodies (p<0.0001 for both. IgG anti-LPS antibodies, from sera of HIV-infected individuals that inhibit killing at high concentration, induced killing when diluted. Conversely, IgG, from sera of HIV-uninfected adults that induce killing, inhibited killing when concentrated. IgM anti-LPS antibodies from all subjects also induced Salmonella killing. Finally, the inhibitory effect of high concentrations of anti-LPS antibodies is seen with IgM as well as IgG and IgA. No correlation was found between affinity or avidity, or complement deposition or consumption, and inhibition of killing.IgG and IgM classes of anti-S. Typhimurium LPS antibodies from HIV-infected and HIV-uninfected individuals are bactericidal, while at very high concentrations, anti-LPS antibodies of all classes inhibit in vitro killing of Salmonella. This could be due to a variety of mechanisms relating to the poor ability of IgA and IgG2 to activate complement, and deposition of complement at sites where it cannot insert in the bacterial membrane. Vaccine trials are required to understand the significance of

  16. Bactericide Effect of Silver Nanoparticles as a Final Irrigation Agent in Endodontics on Enterococcus faecalis: An Ex Vivo Study

    Directory of Open Access Journals (Sweden)

    Pedro-IV González-Luna

    2016-01-01

    Full Text Available The objective of this study was to determine the bactericidal effect of silver nanoparticles as a final irrigation agent in endodontics. This study included 120 uniradicular extracted dental organs inoculated with Enterococcus faecalis (E. faecalis and organized into 4 groups: (A 30 teeth irrigated with a dispersion of silver nanoparticles (537 μg/mL; (B 30 teeth irrigated with a sodium hypochlorite solution (2.25%; (C 30 teeth irrigated with a dispersion of silver nanoparticles (537 μg/mL + EDTA (17%; and (D 30 teeth with a saline solution. After the irrigation protocol, the samples were analyzed through a spectrophotometer to measure the bactericidal effect and scanning electron microscope and atomic force microscope in order to observe the presence of dental smear layer. The results showed that nanoparticles of 10 nm and the sodium hypochlorite at 2.25% were effective for eliminating E. faecalis, with no significant difference between them.

  17. The bactericidal effect of carbon nanotube/agar composites irradiated with near-infrared light on Streptococcus mutans

    Energy Technology Data Exchange (ETDEWEB)

    Akasaka, Tsukasa, E-mail: akasaka@den.hokudai.ac.jp [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan); Matsuoka, Makoto [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan); Hashimoto, Takeshi [Meijo Nano Carbon Co. Ltd., Otsubashi bldg. 4F, 3-4-10 Marunouchi, Naka-ku, Nagoya 460-0002 (Japan); Abe, Shigeaki; Uo, Motohiro; Watari, Fumio [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan)

    2010-10-15

    Dental caries are mainly associated with oral pathogens, and Streptococcus mutans is a primary cariogenic organism. Many methods have been established to eliminate S. mutans from the oral cavity. This study aimed to evaluate the effect of carbon nanotube (CNT)/agar composites irradiated with near-infrared (NIR) light on S. mutans, as a potential photothermal antimicrobial nanotherapy. A colony-forming unit assay clearly showed that CNT/agar composites attain bactericidal activity after NIR light irradiation; this bactericidal activity is higher than that of graphite (GP)/agar and activated carbon (AC)/agar composites. Furthermore, it was observed that longer irradiation times immobilized S. mutans in the CNT/agar composite.

  18. In vitro bactericidal and fungicidal activities of various extracts of saffron (Crocus sativus L. stigmas from Jammu & Kashmir, India

    Directory of Open Access Journals (Sweden)

    Syed Muzaffar

    2016-12-01

    Full Text Available Antimicrobial activities of methanolic and petroleum ether extracts of Croccus sativus L. (saffron stigmas, were tested against various bacterial strains (Proteus vulgaris, Klebsiella pneumonia, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and fungi (Candida albicans, Aspergillus niger and Aspergillus fumigatus by agar well diffusion method. Minimal inhibitory concentration and minimum bactericidal and fungicidal concentration values of each active extract were also determined. The results showed a strong activity of the petroleum ether and methanolic extracts of saffron stigmas against bacteria and fungi used as test organisms. The results of different antimicrobial assays also indicate that the extracts had significantly higher bactericidal than fungicidal activities (p < 0.05. The results suggest that these extracts can be used in pharmaceutical and food formulations for inhibiting pathogenic bacterial and fungal species.

  19. MINIMUM INHIBITORY AND BACTERICIDAL CONCENTRATIONS OF THEAFLAVIN AND SYNGERGISTIC COMBINATIONS WITH EPICATECHIN AND QUERCETIN AGAINST CLINICAL ISOLATES OF STENOTROPHOMONAS MALTOPHILIA

    Directory of Open Access Journals (Sweden)

    Stephen Haswell

    2012-04-01

    Full Text Available Stenotrophomonas maltophilia is an important nosocomial pathogen with intrinsic resistance to multiple antibiotics. Previous investigations have shown flavanols from black tea to possess antibacterial activity. This study describes the determination of minimum inhibitory concentrations and minimum bactericidal concentration for theaflavin independently and in formulations with the polyphenols epicatechin and quercetin against nine clinical isolates of Stenotrophomonas maltophilia and the control isolate NCTC 130141 via the microtitre assay. The results demonstrate that theaflavin has strong antibacterial activity and also shows significant synergism with epicatechin and quercetin. The minimum inhibitory concentrations of the isolates range between 200-400 g/mL for theaflavin and 100-200 g/mL for both theaflavin:epicatechin and theaflavin:quercetin combinations. The minimum bactericidal concentrations were discovered to be a 2 fold increase on those of the minimum inhibitory concentrations. The research highlights the potential use of polyphenols for the clinical treatment of highly antibiotic resistant bacteria

  20. Development of a high-throughput method to evaluate serum bactericidal activity using bacterial ATP measurement as survival readout

    Science.gov (United States)

    Saul, Allan; Rondini, Simona

    2017-01-01

    Serum Bactericidal Activity (SBA) assay is the method of choice to evaluate the complement-mediated functional activity of both infection- and vaccine-induced antibodies. To perform a typical SBA assay, serial dilutions of sera are incubated with target bacterial strains and complement. The conventional SBA assay is based on plating on agar the SBA reaction mix and counting the surviving bacterial colony forming units (CFU) at each serum dilution. Even with automated colony counting, it is labor-intensive, time-consuming and not amenable for large-scale studies. Here, we have developed a luminescence-based SBA (L-SBA) method able to detect surviving bacteria by measuring their ATP. At the end of the SBA reaction, a single commercially available reagent is added to each well of the SBA plate, and the resulting luminescence signal is measured in a microplate reader. The signal obtained is proportional to the ATP present, which is directly proportional to the number of viable bacteria. Bactericidal activity is subsequently calculated. We demonstrated the applicability of L-SBA with multiple bacterial serovars, from 5 species: Citrobacter freundii, Salmonella enterica serovars Typhimurium and Enteritidis, Shigella flexneri serovars 2a and 3a, Shigella sonnei and Neisseria meningitidis. Serum bactericidal titers obtained by the luminescence readout method strongly correlate with the data obtained by the conventional agar plate-based assay, and the new assay is highly reproducible. L-SBA considerably shortens assay time, facilitates data acquisition and analysis and reduces the operator dependency, avoiding the plating and counting of CFUs. Our results demonstrate that L-SBA is a useful high-throughput bactericidal assay. PMID:28192483

  1. Studies on characteristics of nanostructure of N-TiO2 thin films and photo-bactericidal action.

    Science.gov (United States)

    Xu, Ming-fang; Lin, Shan; Chen, Xin-man; Peng, Yan-zhi

    2006-07-01

    Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis strain (AS1.439) from Ming lake were decomposed by photocatalytic nanostructure N-TiO(2) thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO(2) thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 degrees C (films A) or 350 degrees C (films B) for 1 h in a muffle furnace. The results showed that N-TiO(2) thin film B (8.18 nm thickness, 2.760 nm height and 25.15 nm diameter) has more uniform granular nanostructure and thinner flat texture than N-TiO(2) thin film A (12.17 nm thickness, 3.578 nm height and 27.50 nm diameter). The bactericidal action of N-TiO(2) thin film A and film B for Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis varniger strain (AS1.439) were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain (AS1.50) and 75% for Bacillus subtilis strain (AS1.439) were achieved by using N-TiO(2) thin films-B for 70-80 min of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO(2) thin films probably depended on the characteristics of the films.

  2. Studies on characteristics of nanostructure of N-TiO2 thin films and photo-bactericidal action

    Institute of Scientific and Technical Information of China (English)

    XU Ming-fang; LIN Shan; CHEN Xin-man; PENG Yan-zhi

    2006-01-01

    Pseudomonas aeruginosa strain (AS 1.50) and Bacillus subtilis strain ( AS 1.49 ) from Ming lake were decomposed by photocatalytic nanostructure N-TiO2 thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO2 thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 ℃ (films A) or 350 ℃ (films B)for 1 h in a muffle furnace. The results showed that N-TiO2 thin film B (8.18 nm thickness, 2.760 nm height and 25.15 nm diameter) has more uniform granular nanostructure and thinner flat texture than N-TiO2 thin film A (12.17 nm thickness, 3.578 nm height and 27.50 nm diameter). The bactericidal action of N-TiO2 thin film A and film B for Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis varniger strain (AS1.439) were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain (AS1.50) and 75% for Bacillus subtilis strain (AS1.439) were achieved by using N-TiO2 thin films-B for 70~80 min of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO2 thin films probably depended on the characteristics of the films.

  3. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles.

    Science.gov (United States)

    Gopal, Judy; Muthu, Manikandan; Paul, Diby; Kim, Doo-Hwan; Chun, Sechul

    2016-01-28

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300 mL water contains about 50 mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been screened against green tea extracts and macro, micro and nano sized green tea particles. The results showed that the presence/absence of the macro and mico sized tea particles in the green tea extract did not contribute much. However, the nano sized particles were characterized to be nature's nano stores of the bioactive catechins. Eradication of these nano tea particles resulted in decrease in the bactericidal property of the green tea extracts. This is a curtain raiser investigation, busting the nano as well as green tea leaf particle contribution in green tea extracts.

  4. Plasma-enhanced synthesis of bactericidal quaternary ammonium thin layers on stainless steel and cellulose surfaces.

    Science.gov (United States)

    Jampala, Soujanya N; Sarmadi, M; Somers, E B; Wong, A C L; Denes, F S

    2008-08-19

    We have investigated bottom-up chemical synthesis of quaternary ammonium (QA) groups exhibiting antibacterial properties on stainless steel (SS) and filter paper surfaces via nonequilibrium, low-pressure plasma-enhanced functionalization. Ethylenediamine (ED) plasma under suitable conditions generated films rich in secondary and tertiary amines. These functional structures were covalently attached to the SS surface by treating SS with O 2 and hexamethyldisiloxane plasma prior to ED plasma treatment. QA structures were formed by reaction of the plasma-deposited amines with hexyl bromide and subsequently with methyl iodide. Structural compositions were examined by electron spectroscopy for chemical analysis and Fourier transform infrared spectroscopy, and surface topography was investigated with atomic force microscopy and water contact angle measurements. Modified SS surfaces exhibited greater than a 99.9% decrease in Staphylococcus aureus counts and 98% in the case of Klebsiella pneumoniae. The porous filter paper surfaces with immobilized QA groups inactivated 98.7% and 96.8% of S. aureus and K. pneumoniae, respectively. This technique will open up a novel way for the synthesis of stable and very efficient bactericidal surfaces with potential applications in development of advanced medical devices and implants with antimicrobial surfaces.

  5. Biofunctionalization of microgroove titanium surfaces with an antimicrobial peptide to enhance their bactericidal activity and cytocompatibility.

    Science.gov (United States)

    Zhou, Lin; Lai, Yingzhen; Huang, Wenxiu; Huang, Sijia; Xu, Zhiqiang; Chen, Jiang; Wu, Dong

    2015-04-01

    A firm peri-implant soft tissue seal is important for the long-term survival of dental implants, which demands the properties of antibacterial and cytocompatibility of the implant surfaces. In this study, GL13K, a cationic antimicrobial peptide, was immobilized onto microgroove surfaces which were 60 μm in width and 10 μm in depth, and the modified surfaces improved both the properties of antibacterial and cytocompatibility. The method of silanization was used to immobilize the antimicrobial peptide GL13K, which was confirmed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle measurement. Then the mechanical stability of the coatings was confirmed by ultrasonication. In vitro antibacterial tests confirmed bactericidal activity against Porphyromonas gingivalis without inhibiting its adhesion. In vitro cytocompatibility tests also confirmed that adhesion at later phase and proliferation of HGFs were greater (P<0.01) on the GL13K-modified microgroove surfaces than on the non-treated microgroove surfaces, and both of them were greater than on the smooth surfaces. The phenomenon of the contact guidance, which is cell growth aligned along the microgrooves, was maintained. Overall, this study developed a promising bi-functional surface that combined the physical and chemical properties to promote cytocompatibility and antibacterial activity simultaneously.

  6. Cefazolin-loaded mesoporous silicon microparticles show sustained bactericidal effect against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Iman K Yazdi

    2014-05-01

    Full Text Available Cefazolin is an antibiotic frequently used in preoperative prophylaxis of orthopedic surgery and to fight secondary infections post-operatively. Although its systemic delivery in a bulk or bolus dose is usually effective, the local and controlled release can increase its effectiveness by lowering dosages, minimizing total drug exposure, abating the development of antibiotic resistance and avoiding the cytotoxic effect. A delivery system based on mesoporous silicon microparticles was developed that is capable of efficiently loading and continuously releasing cefazolin over several days. The in vitro release kinetics from mesoporous silicon microparticles with three different nanopore sizes was evaluated, and minimal inhibitory concentration of cefazolin necessary to eliminate a culture of Staphylococcus aureus was identified to be 250 µg/mL. A milder toxicity toward mesenchymal stem cells was observed from mesoporous silicon microparticles over a 7-day period. Medium pore size-loaded mesoporous silicon microparticles exhibited long-lasting bactericidal properties in a zone inhibition assay while they were able to kill all the bacteria growing in suspension cultures within 24 h. This study demonstrates that the sustained release of cefazolin from mesoporous silicon microparticles provides immediate and long-term control over bacterial growth both in suspension and adhesion while causing minimal toxicity to a population of mesenchymal stem cell. Mesoporous silicon microparticles offer significant advantageous properties for drug delivery applications in tissue engineering as it favorably extends drug bioavailability and stability, while reducing concomitant cytotoxicity to the surrounding tissues.

  7. Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.

    Directory of Open Access Journals (Sweden)

    Guocai Li

    Full Text Available Neisseria gonorrhoeae (N. gonorrhoeae outer membrane protein reduction modifiable protein (Rmp has strong immunogenicity. However, anti-Rmp antibodies block rather than preserve the antibacterial effects of protective antibodies, which hampers the development of vaccines for gonococcal infections. We herein constructed an Rmp deletion mutant strain of N. gonorrhoeae by gene homologous recombination. The 261-460 nucleotide residues of Rmp gene amplified from N. gonorrhoeae WHO-A strain were replaced with a kanamycin-resistant Kan gene amplified from pET-28a. The resultant hybridized DNA was transformed into N. gonorrhoeae WHO-A strain. PCR was used to screen the colonies in which wild-type Rmp gene was replaced with a mutant gene fragment. Western blotting revealed that the Rmp deletion mutant strain did not express Rmp protein. Rmp deletion did not alter the morphological and Gram staining properties of the mutant strain that grew slightly more slowly than the wild-type one. Rmp gene mutated stably throughout 25 generations of passage. Antibody-mediated complement-dependent cytotoxicity assay indicated that the antibodies induced by the mutant strain had evidently higher bactericidal activities than those induced by the wild-type strain. Further modification of the Rmp deletion mutant strain is still required in the development of novel live attenuated vaccines for gonorrhea by Opa genes deletion or screening of phenotypic variant strains that do not express Opa proteins.

  8. Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.

    Science.gov (United States)

    Li, Guocai; Xie, Rushan; Zhu, Xiaoping; Mao, Yanli; Liu, Shuangxi; Jiao, Hongmei; Yan, Hua; Xiong, Kun; Ji, Mingchun

    2014-01-01

    Neisseria gonorrhoeae (N. gonorrhoeae) outer membrane protein reduction modifiable protein (Rmp) has strong immunogenicity. However, anti-Rmp antibodies block rather than preserve the antibacterial effects of protective antibodies, which hampers the development of vaccines for gonococcal infections. We herein constructed an Rmp deletion mutant strain of N. gonorrhoeae by gene homologous recombination. The 261-460 nucleotide residues of Rmp gene amplified from N. gonorrhoeae WHO-A strain were replaced with a kanamycin-resistant Kan gene amplified from pET-28a. The resultant hybridized DNA was transformed into N. gonorrhoeae WHO-A strain. PCR was used to screen the colonies in which wild-type Rmp gene was replaced with a mutant gene fragment. Western blotting revealed that the Rmp deletion mutant strain did not express Rmp protein. Rmp deletion did not alter the morphological and Gram staining properties of the mutant strain that grew slightly more slowly than the wild-type one. Rmp gene mutated stably throughout 25 generations of passage. Antibody-mediated complement-dependent cytotoxicity assay indicated that the antibodies induced by the mutant strain had evidently higher bactericidal activities than those induced by the wild-type strain. Further modification of the Rmp deletion mutant strain is still required in the development of novel live attenuated vaccines for gonorrhea by Opa genes deletion or screening of phenotypic variant strains that do not express Opa proteins.

  9. Biosynthesis and recovery of rod-shaped tellurium nanoparticles and their bactericidal activities

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Bijan; Faramarzi, Mohammad Ali; Sepehrizadeh, Zargham [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451 Tehran (Iran, Islamic Republic of); Shakibaie, Mojtaba [Department of Pharmacognosy and Biotechnology, School of Pharmacy, Pharmaceutics Research Center, Kerman University of Medical Sciences, P.O. Box 76175-493 Kerman (Iran, Islamic Republic of); Rezaie, Sassan [Department of Medical Biotechnology, School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza, E-mail: shahverd@sina.tums.ac.ir [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451 Tehran (Iran, Islamic Republic of)

    2012-11-15

    Highlights: ► Biosynthesis of rod shape tellurium nanoparticles with a hexagonal crystal structure. ► Extraction procedure for isolation of tellurium nanoparticles from Bacillus sp. BZ. ► Extracted tellurium nanoparticles have good bactericidal activity against some bacteria. -- Abstract: In this study, a tellurium-transforming Bacillus sp. BZ was isolated from the Caspian Sea in northern Iran. The isolate was identified by various tests and 16S rDNA analysis, and then used to prepare elemental tellurium nanoparticles. The isolate was subsequently used for the intracellular biosynthesis of elemental tellurium nanoparticles. The biogenic nanoparticles were released by liquid nitrogen and purified by an n-octyl alcohol water extraction system. The shape, size, and composition of the extracted nanoparticles were characterized. The transmission electron micrograph showed rod-shaped nanoparticles with dimensions of about 20 nm × 180 nm. The energy dispersive X-ray and X-ray diffraction spectra respectively demonstrated that the extracted nanoparticles consisted of only tellurium and have a hexagonal crystal structure. This is the first study to demonstrate a biological method for synthesizing rod-shaped elemental tellurium by a Bacillus sp., its extraction and its antibacterial activity against different clinical isolates.

  10. Bactericidal performance of visible-light responsive titania photocatalyst with silver nanostructures.

    Directory of Open Access Journals (Sweden)

    Ming-Show Wong

    Full Text Available BACKGROUND: Titania dioxide (TiO(2 photocatalyst is primarily induced by ultraviolet light irradiation. Visible-light responsive anion-doped TiO(2 photocatalysts contain higher quantum efficiency under sunlight and can be used safely in indoor settings without exposing to biohazardous ultraviolet light. The antibacterial efficiency, however, remains to be further improved. METHODOLOGY/PRINCIPAL FINDINGS: Using thermal reduction method, here we synthesized silver-nanostructures coated TiO(2 thin films that contain a high visible-light responsive antibacterial property. Among our tested titania substrates including TiO(2, carbon-doped TiO(2 [TiO(2 (C] and nitrogen-doped TiO(2 [TiO(2 (N], TiO(2 (N showed the best performance after silver coating. The synergistic antibacterial effect results approximately 5 log reductions of surviving bacteria of Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Acinetobacter baumannii. Scanning electron microscope analysis indicated that crystalline silver formed unique wire-like nanostructures on TiO(2 (N substrates, while formed relatively straight and thicker rod-shaped precipitates on the other two titania materials. CONCLUSION/SIGNIFICANCE: Our results suggested that proper forms of silver on various titania materials could further influence the bactericidal property.

  11. Intraphagocytic bactericidal activity of ofloxacin compared with that of aztreonam and ceftriaxone against Serratia marcescens.

    Science.gov (United States)

    Traub, W H; Spohr, M; Bauer, D

    1986-02-01

    Addition of phenylbutazone (2 mg/ml) to 55 vol % of fresh defibrinated human blood permitted leukocytic ingestion of serum-resistant Serratia marcescens bacteria, but blocked phagocytic killing activity. The group A (phage tail) bacteriocin bA+ 16 served to kill extraphagocytic test bacteria. At greater than or equal to 2 X MBC, the DNA gyrase inhibitor ofloxacin revealed potent intraphagocytic bactericidal activity against S. marcescens test bacteria (99% kill; 3 h observation period) which corresponded to that of the control drug rifampin (97% kill). The monobactam aztreonam (11% kill) and the third generation cephalosporin ceftriaxone (14% kill) corresponded to cefotaxime (26% kill) in terms of suboptimal intraphagocytic activity. Ofloxacin and aztreonam yielded additive effects following combination of supra-(2 X MIC) and inhibitory (MIC), but not sub-inhibitory (0.5 X MIC) concentrations with 55 vol % of defibrinated human blood against S. marcescens and Escherichia coli control strain ATCC 25922; sub- and inhibitory concentrations of ceftriaxone yielded indifferent effects.

  12. Bactericidal effect of the 908 nm diode laser on Enterococcus faecalis in infected root canals

    Directory of Open Access Journals (Sweden)

    Thomas Preethee

    2012-01-01

    Full Text Available Aim: The aim of this study is to evaluate the bactericidal effect of 908 nm diode laser in conjunction with various irrigation regimes in disinfection of apical third of root dentin. Materials and Methods: Sixty prepared teeth with single canals were contaminated with Enterococcus faecalis. The specimens were divided into 6 groups (n = 10: Group 1 and 3 and 5 were subjected to chemo-mechanical preparation using 5.25% sodium hypochlorite (NaOCl, 17% Ethylenediaminetetraacetic acid (EDTA; 1.3% NaOCl, MTAD (mixture of doxycycline, citric acid and a detergent (Tween 80; and, 8.5% saline, respectively followed by 908 nm diode laser irradiation; Group 2 and 4, followed the same procedure as Group1 and 3, however without laser irradiation; and, Group 6, rinsed with saline solution (control. Dentin shavings from apical third were analyzed for the presence of E. faecalis using culture method and Polymerase Chain reaction (PCR. Results: One-way Analysis of variance showed statistically significant differences between the laser irradiated groups, non irradiated groups and the control group. Conclusion: 908 nm diode used in conjunction with conventional chemomechanical techniques demonstrated a significant elimination of E. faecalis in the apical third of root dentin.

  13. Dextromethorphan Efficiently Increases Bactericidal Activity, Attenuates Inflammatory Responses, and Prevents Group A Streptococcal Sepsis▿ †

    Science.gov (United States)

    Li, Ming-Han; Luo, Yueh-Hsia; Lin, Chiou-Feng; Chang, Yu-Tzu; Lu, Shiou-Ling; Kuo, Chih-Feng; Hong, Jau-Shyong; Lin, Yee-Shin

    2011-01-01

    Group A streptococcus (GAS) is an important human pathogen that causes a wide spectrum of diseases, ranging from mild throat and skin infections to severe invasive diseases such as necrotizing fasciitis and streptococcal toxic shock syndrome. Dextromethorphan (DM), a dextrorotatory morphinan and a widely used antitussive drug, has recently been reported to possess anti-inflammatory properties. In this study, we investigated the potential protective effect of DM in GAS infection using an air pouch infection mouse model. Our results showed that DM treatment increased the survival rate of GAS-infected mice. Bacterial numbers in the air pouch were lower in mice treated with DM than in those infected with GAS alone. The bacterial elimination efficacy was associated with increased cell viability and bactericidal activity of air-pouch-infiltrating cells. Moreover, DM treatment prevented bacterial dissemination in the blood and reduced serum levels of the proinflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-1β and the chemokines monocyte chemotactic protein 1 (MCP-1), macrophage inflammatory protein 2 (MIP-2), and RANTES. In addition, GAS-induced mouse liver injury was reduced by DM treatment. Taken together, DM can increase bacterial killing and reduce inflammatory responses to prevent sepsis in GAS infection. The consideration of DM as an adjunct treatment in combination with antibiotics against bacterial infection warrants further study. PMID:21199930

  14. [Physiology and pathology of bactericidal activity in human polymorphonuclear neutrophils (author's transl)].

    Science.gov (United States)

    Hakim, J

    1980-09-13

    Blood polymorphonuclear neutrophils defend man against aggressions from pathogens. Under the combined influence of granulocytic and non-granulocytic factors, the defensive process develops by steps: the neutrophil moves towards the pathogenic organism which, one reached, is engulfed and killed. The killing systems of the cell are either oxygen-dependent or independent. the oxygen-dependent system is triggered off by stimulation of the cell membrane and involves various reactions, including cyanide-resistant oxygen consumption, production of activated oxygen, oxygen peroxide and halogenisation of the pathogen membrane. Impairment of the killing activity requires quantitative assessment of its various components in the presence of autologous or control serum with the view of: determining the origin (granulocytic or non-granulocytic) of the impairment, and identifying the step in oxygen metabolism that is affected. In the vast majority of non-granulocytic insufficiencies the cause lies in defective opsonins. In granulocytic insufficiencies, global failure of the system indicates chromic granulomatous disease, a syndrome that is now being dismembered. Defective halogenisation should lead to testing for deficiency of myeloperoxidase or abnormal degranulation. The non oxygen-independent bactericidal system, although highly effective in vitro, appears to be less important in vivo than the oxygen-dependent system. Little is known of its pathology.

  15. Synthesis of nanosilver particles by reverse micelle method and study of their bactericidal properties

    Energy Technology Data Exchange (ETDEWEB)

    Tran Thi Ngoc Dung; Ngo Quoc Buu; Dang Viet Quang; Le Anh Bang; Nguyen Hoai Chau; Nguyen Thi Ly [Institute of Environmental Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Huynh Thi Ha [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Nguyen Vu Trung [National Institute for Infectious and Tropical Diseases, 1 Ton That Tung, Dong Da Distr., Hanoi (Viet Nam)], E-mail: ttndzung@yahoo.com, E-mail: buu_nq@yahoo.com

    2009-09-01

    Nanosilver particles have been synthesized by the reverse micelle method, where AgNO{sub 3} was used as a silver ions source, NaBH{sub 4} and quercetin - as reducing agents, CTAB, SDOSS and AOT- as surfactants, while the stabilizer was Vietnamese chitosan. Studying the factors influencing the process of nanosilver particle formation, it was shown that the particle size of the nanosilver products depends on the concentration of the reaction components and their stoichiometric ratio. It was also shown that the reaction system using AOT surfactant is capable of producing nanosilver particles with smallest nanoparticles ({phi}{sub av} {approx} 5 nm) and good particle-size distribution. The study on bactericidal activity of the nanosilver products indicated that the disinfecting solution with a nanosilver concentration of 3 ppm was able to inhibit all E.coli and Coliforms, TPC and fungi at 15 ppm, while Vibrio cholerae cells were inactivated completely with 0.5 ppm of nanosilver after 30 minutes exposition.

  16. Anti-listerial Bactericidal Activity of Lactobacillus plantarum DM5 Isolated from Fermented Beverage Marcha.

    Science.gov (United States)

    Das, Deeplina; Goyal, Arun

    2013-09-01

    The strain Lactobacillus plantarum DM5 was isolated from fermented beverage Marcha of Sikkim and explored for its antagonistic activity against food-borne pathogens. The cell-free supernatant of L. plantarum DM5 showed antibacterial activity of 6,400 AU/mL in MRS medium (pH 6.0) against the indicator strain Staphylococcus aureus. MRS medium supplemented with 15 g/L of maltose at 37 °C under static condition yielded highest antimicrobial activity (6,400 AU/mL) with 3 % increase in specific activity when compared to 20 g/L glucose. The antimicrobial compound was heat stable (60 min at 100 °C) and was active over a wide pH range. It showed bactericidal effect on S. aureus and Listeria monocytogenes by causing 96 and 98 % of cell lysis, respectively. The cell morphology of the treated S. aureus and L. monocytogenes was completely deformed as revealed by scanning electron microscopy, suggesting the high potential of L. plantarum DM5 as natural preservatives in food industry. The antimicrobial compound was purified by 80 % ammonium sulphate precipitation and showed antimicrobial activity of 12,800 AU/mL with 19-fold purification and a molecular mass of 15.2 kDa, indicating the proteinaceous nature of the compound.

  17. Monoclonal antibodies against the iron regulated outer membrane Proteins of Acinetobacter baumannii are bactericidal

    Directory of Open Access Journals (Sweden)

    Goel Vikas

    2001-08-01

    Full Text Available Abstract Background Iron is an important nutrient required by all forms of life.In the case of human hosts,the free iron availability is 10-18M,which is far less than what is needed for the survival of the invading bacterial pathogen.To survive in such conditions, bacteria express new proteins in their outer membrane and also secrete iron chelators called siderophores. Results/ Discussion Acinetobacter baumannii ATCC 19606, a nosocomial pathogen which grows under iron restricted conditions, expresses four new outer membrane proteins,with molecular weight ranging from 77 kDa to 88 kDa, that are called Iron Regulated Outer Membrane Proteins (IROMPs. We studied the functional and immunological properties of IROMPs expressed by A.baumanii ATCC 19606.The bands corresponding to IROMPs were eluted from SDS-PAGE and were used to immunize BALB/c mice for the production of monoclonal antibodies. Hybridomas secreting specific antibodies against these IROMPs were selected after screening by ELISA and their reactivity was confirmed by Western Blot. The antibodies then generated belonged to IgM isotype and showed bactericidical and opsonising activities against A.baumanii in vitro.These antibodies also blocked siderophore mediated iron uptake via IROMPs in bacteria. Conclusion This proves that iron uptake via IROMPs,which is mediated through siderophores,may have an important role in the survival of A.baumanii inside the host,and helps establishing the infection.

  18. Interaction of iodine with 2-hydroxypropyl-alpha-cyclodextrin and its bactericidal activity.

    Science.gov (United States)

    Tomono, K; Goto, H; Suzuki, T; Ueda, H; Nagai, T; Watanabe, J

    2002-11-01

    To obtain an effective iodine solution, the use of 2-hydroxypropyl-alpha-cyclodextrin (2-HP-alpha-CD) as solubilizer was examined in comparison with alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), potassium iodide (KI), and polyvinylpyrrolidone (PVP). The stability constants for inclusion of iodine with cyclodextrin and KI were ascertained by the solubility method. The apparent stability constants increased in the following order: KI stabilization ability. The largest volatile depression effect was exhibited by 2HP-alpha-CD. The measurement of the minimum inhibitory concentration (MC) using Escherichia coli NIH-J-2 and Staphylococcus aureus FDA209P suggested that the bactericidal activity of the iodine/2-HP-alpha-CD system was the same as that of the iodine/alpha-CD, iodine/beta-CD, and iodine/PVP systems. The present results suggest that the combination of 2-HP-alpha-CD and iodine is useful for a stable and effective iodine solution.

  19. The study of cellulosic fabrics impregnated with porphyrin compounds for use as photo-bactericidal polymers

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Rahmatollah, E-mail: rahimi_rah@iust.ac.ir [Bioinorganic Chemistry Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114 (Iran, Islamic Republic of); Fayyaz, Fatemeh [Bioinorganic Chemistry Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114 (Iran, Islamic Republic of); Rassa, Mehdi [Department of Biology, Faculty of Science, University of Guilan, Rasht (Iran, Islamic Republic of)

    2016-02-01

    In the present work, we report on the preparation of cellulosic fabrics bearing two types of photo-sensitizers in order to prepare efficient polymeric materials for antimicrobial applications. The obtained porphyrin-grafted cellulosic fabrics were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, diffuse reflectance UV–Vis (DRUV) spectroscopy, thermo-gravimetric analysis (TG) and scanning electron microscopy (SEM). Antimicrobial activity of the prepared porphyrin-cellulose was tested under visible light irradiation against Staphylococcus aureus, Pseudomunas aeroginosa and Escherichia coli. In addition, the effect of two parameters on photo-bactericidal activity of treated fibers was studied: illumination time and concentration of photosensitizers (PS). - Highlights: • Cellulosic fabrics were impregnated with various concentrations of porphyrins (TAPP and its zinc ion complex). • The products were characterized by ATR-FTIR, DRUV, SEM and TG. • The photo-antibacterial activity of products was determined against S. aureus, P. aeroginosa and E. coli. • The effect of two parameters were studied on photoinactivation of treated fibers: illumination time and concentration of PS.

  20. Bactericidal paper trays doped with silver nanoparticles for egg storing applications

    Indian Academy of Sciences (India)

    KALIYAPERUMAL VISWANATHAN; M LATHA MALA PRIYADHARSHINI; KARUPPASAMY NIRMALA; MUTHUSAMY RAMAN; GOPAL DHINAKAR RAJ

    2016-06-01

    In this study, a cost-effective way to deposit the silver nanoparticles (AgNPs) on paper egg trays was developed, which proved suitable for prolonged storage of table eggs for house-hold use without deterioration of egg quality. Silver nanoparticles were synthesized based on chemical reduction approach and mixed with gelatin–chitosan mixer used as a colloidal stabilizer as well as fixing agent. AgNPs-doped paper egg trays were characterized by TEM, SEM, FTIR, EDX and XRD. AgNPs containing egg trays were tested for its bactericidal effect against commonly found bacteria on egg shells, E. coli, S. aureus, Streptococcus spp and Salmonella spp. Storing of eggs in the AgNPs-deposited paper egg trays improved the shelf-life of the eggs by more than 14 days compared to controls (eggs stored in conventional trays). In conclusion, the developed paper trays possessed strong antimicrobial activity and it could be an effective storage material for eggs.

  1. Structure of the meningococcal vaccine antigen NadA and epitope mapping of a bactericidal antibody.

    Science.gov (United States)

    Malito, Enrico; Biancucci, Marco; Faleri, Agnese; Ferlenghi, Ilaria; Scarselli, Maria; Maruggi, Giulietta; Lo Surdo, Paola; Veggi, Daniele; Liguori, Alessia; Santini, Laura; Bertoldi, Isabella; Petracca, Roberto; Marchi, Sara; Romagnoli, Giacomo; Cartocci, Elena; Vercellino, Irene; Savino, Silvana; Spraggon, Glen; Norais, Nathalie; Pizza, Mariagrazia; Rappuoli, Rino; Masignani, Vega; Bottomley, Matthew James

    2014-12-02

    Serogroup B Neisseria meningitidis (MenB) is a major cause of severe sepsis and invasive meningococcal disease, which is associated with 5-15% mortality and devastating long-term sequelae. Neisserial adhesin A (NadA), a trimeric autotransporter adhesin (TAA) that acts in adhesion to and invasion of host epithelial cells, is one of the three antigens discovered by genome mining that are part of the MenB vaccine that recently was approved by the European Medicines Agency. Here we present the crystal structure of NadA variant 5 at 2 Å resolution and transmission electron microscopy data for NadA variant 3 that is present in the vaccine. The two variants show similar overall topology with a novel TAA fold predominantly composed of trimeric coiled-coils with three protruding wing-like structures that create an unusual N-terminal head domain. Detailed mapping of the binding site of a bactericidal antibody by hydrogen/deuterium exchange MS shows that a protective conformational epitope is located in the head of NadA. These results provide information that is important for elucidating the biological function and vaccine efficacy of NadA.

  2. Drug delivery property, bactericidal property and cytocompatibility of magnetic mesoporous bioactive glass.

    Science.gov (United States)

    Liu, Yi-Zhuo; Li, Yang; Yu, Xi-Bin; Liu, Li-Na; Zhu, Zhen-An; Guo, Ya-Ping

    2014-08-01

    A multifunctional magnetic mesoporous bioactive glass (MMBG) has been widely used for a drug delivery system, but its biological properties have been rarely reported. Herein, the effects of mesopores and Fe3O4 nanoparticles on drug loading-release property, bactericidal property and biocompatibility have been investigated by using mesoporous bioactive glass (MBG) and non-mesoporous bioactive glass (NBG) as control samples. Both MMBG and MBG have better drug loading efficiency than NBG because they possess ordered mesoporous channels, big specific surface areas and high pore volumes. As compared with MBG, the Fe3O4 nanoparticles in MMBG not only provide magnetic property, but also improve sustained drug release property. For gentamicin-loaded MMBG (Gent-MMBG), the sustained release of gentamicin and the Fe3O4 nanoparticles minimize bacterial adhesion significantly and prevent biofilm formation against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). Moreover, the magnetic Fe3O4 nanoparticles in MMBG can promote crucial cell functions such as cell adhesion, spreading and proliferation. The excellent biocompatibility and drug delivery property of MMBG suggest that Gent-MMBG has great potentials for treatment of implant-associated infections.

  3. Verapamil increases the bacteriostatic and bactericidal effects of adriamycin on Escherichia coli.

    Science.gov (United States)

    Abramov, Y; Aronovitch, J; Ramu, A

    1996-01-01

    The purpose of this study was to evaluate the effect of verapamil on adriamycin-resistant and -sensitive Escherichia coli bacterial strains. Two E. coli strains: B-SR9 and K12-KL16 were incubated with adriamycin in various concentrations in the presence or absence of verapamil. Growth and killing rates were measured using optical densities and colonogenic assays. Transmembrane transport capacity was evaluated by measuring radioactively labelled leucine uptake and intracellular potassium concentrations. While adriamycin (ADR) showed both bacteriostatic and bactericidal effects upon the two bacterial strains, the K12 strain was significantly more resistant to the drug than its peer. Subtoxic concentrations of verapamil augmented these effects in both strains. Verapamil affected bacterial transmembrane transport activity and caused potassium leakage through the cell membrane. Simultaneous exposure to adriamycin and verapamil resulted in rapid, massive damage to membrane functions, indicating accelerated killing rate. The authors concluded that verapamil acts as a potentiator of adriamycin's cytotoxicity in E. coli bacteria in a manner similar to that in multidrug resistant mammalian tumour cells. This observation suggests that the mechanisms of resistance to the drug may be similar in both species.

  4. A comparative study of the bactericidal activity and daily disinfection housekeeping surfaces by a new portable pulsed UV radiation device.

    Science.gov (United States)

    Umezawa, Kazuo; Asai, Satomi; Inokuchi, Sadaki; Miyachi, Hayato

    2012-06-01

    Daily cleaning and disinfecting of non-critical surfaces in the patient-care areas are known to reduce the occurrence of health care-associated infections. However, the conventional means for decontamination of housekeeping surfaces of sites of frequent hand contact such as manual disinfection using ethanol wipes are laborious and time-consuming in daily practice. This study evaluated a newly developed portable pulsed ultraviolet (UV) radiation device for its bactericidal activity in comparison with continuous UV-C, and investigated its effect on the labor burden when implemented in a hospital ward. Pseudomonas aeruginosa, Multidrug-resistant P. aeruginosa, Escherichia coli, Acinetobacter baumannii, Amikacin and Ciprofloxacin-resistant A. baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus cereus were irradiated with pulsed UV or continuous UV-C. Pulsed UV and continuous UV-C required 5 and 30 s of irradiation, respectively, to attain bactericidal activity with more than 2Log growth inhibition of all the species. The use of pulsed UV in daily disinfection of housekeeping surfaces reduced the working hours by half in comparison to manual disinfection using ethanol wipes. The new portable pulsed UV radiation device was proven to have a bactericidal activity against critical nosocomial bacteria, including antimicrobial-resistant bacteria after short irradiation, and was thus found to be practical as a method for disinfecting housekeeping surfaces and decreasing the labor burden.

  5. Anti-bactericidal properties of stingray Dasyatis pastinaca groups V, IIA, and IB phospholipases A2: a comparative study.

    Science.gov (United States)

    Bacha, Abir Ben

    2014-10-01

    Group IIA secreted phospholipase A2 (group IIA sPLA2) is known to display potent Gram-positive bactericidal activity in vitro and in vivo. We have analyzed the bactericidal activity of the full set of native stingray and dromedary groups V, IIA, and IB sPLA2s on several Gram-positive and Gram-negative strains. The rank order potency among both marine and mammal sPLA2s against Gram-positive bacteria is group IIA > V > IB, whereas Gram-negative bacteria exhibited a much higher resistance. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2.The bactericidal efficiency of groups V and IIA sPLA2s was shown to be dependent upon the presence of calcium ions and to a less extent Mg(2+) ions and then a correlation could be made to its hydrolytic activity of membrane phospholipids. Importantly, we showed that stingray and dromedary groups V, IIA, and IB sPLA2s present no cytotoxicity after their incubation with MDA-MB-231cells. stingray groups V and IIA sPLA2s, like mammal ones, may be considered as future therapeutic agents against bacterial infections.

  6. Bactericidal activity under UV and visible light of cotton fabrics coated with anthraquinone-sensitized TiO2

    KAUST Repository

    Rahal, Raed

    2013-06-01

    This study describes a method derived from ISO/TC 206/SC specifications to assess the bactericidal activity against a bacterial strain, Pseudomonas fluorescens, of various photocatalytic fabrics, under UVA and filtered visible light. The experimental method allowed the accurate quantification of bacteria survival on photoactive surfaces and films under UVA and UV-free visible irradiation. Cotton fabrics coated with TiO2, anthraquinone or anthraquinone-sensitized TiO2 display a significant bactericidal efficiency. TiO2-coated fabrics are very efficient against P. fluorescens after 4 h UVA irradiation (bacteria survival below the detection limit). Under UVA-free visible light, anthraquinone-sensitized TiO2 coated fabrics induced a significant bactericidal activity after 2 h irradiation, while anthraquinone alone-coated fabrics were not as efficient and TiO2 coated fabrics were almost inefficient. These results show that although exhibiting a weak n-π* band in the 350-420 nm range, anthraquinone is a good candidate as an efficient visible light photosensitizer. A synergy effect between anthraquinone and TiO2 was demonstrated. A possible reaction mechanism, involving a synergy effect for singlet oxygen formation with anthraquinone-sensitized TiO2 is proposed to account for these results. © 2012 Elsevier B.V. All rights reserved.

  7. Immobilized silver nanoparticles enhance contact killing and show highest efficacy: elucidation of the mechanism of bactericidal action of silver.

    Science.gov (United States)

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-08-21

    Antimicrobial materials with immobilized/entrapped silver nanoparticles (AgNPs) are of considerable interest. There is significant debate on the mode of bactericidal action of AgNPs, and both contact killing and/or ion mediated killing have been proposed. In this study, AgNPs were immobilized on an amine-functionalized silica surface and their bactericidal activity was studied concurrently with the silver release profile over time. This was compared with similar studies performed using colloidal AgNPs and AgCl surfaces that released Ag ions. We conclude that contact killing is the predominant bactericidal mechanism and surface immobilized nanoparticles show greater efficacy than colloidal AgNPs, as well as a higher concentration of silver ions in solution. In addition, the AgNP immobilized substrate was used multiple times with good efficacy, indicating this immobilization protocol is effective for retaining AgNPs while maintaining their disinfection potential. The antibacterial surface was found to be extremely stable in aqueous medium and no significant leaching (∼1.15% of total silver deposited) of the AgNPs was observed. Thus, immobilization of AgNPs on a surface may promote reuse, reduce environmental risks associated with leaching of AgNPs and enhance cost effectiveness.

  8. Bactericidal active ingredient in cryopreserved plasma-treated water with the reduced-pH method for plasma disinfection

    Science.gov (United States)

    Kitano, Katsuhisa; Ikawa, Satoshi; Nakashima, Yoichi; Tani, Atsushi; Yokoyama, Takashi; Ohshima, Tomoko

    2016-09-01

    For the plasma disinfection of human body, plasma sterilization in liquid is crucial. We found that the plasma-treated water (PTW) has strong bactericidal activity under low pH condition. Physicochemical properties of PTW is discussed based on chemical kinetics. Lower temperature brings longer half-life and the bactericidal activity of PTW can be kept by cryopreservation. High performance PTW, corresponding to the disinfection power of 22 log reduction (B. subtilis spore), can be obtained by special plasma system equipped with cooling device. This is equivalent to 65% H2O2, 14% sodium hypochlorite and 0.33% peracetic acid, which are deadly poison for human. But, it is deactivated soon at higher temperature (4 sec. at body temperature), and toxicity to human body seems low. For dental application, PTW was effective on infected models of human extracted tooth. Although PTW has many chemical components, respective chemical components in PTW were isolated by ion chromatography. In addition to peaks of H2O2, NO2- and NO3-, a specific peak was detected. and only this fraction had bactericidal activity. Purified active ingredient of PTW is the precursor of HOO, and further details will be discussed in the presentation. MEXT (15H03583, 23340176, 25108505). NCCE (23-A-15).

  9. Comparative study of bactericidal activities, postantibiotic effects, and effects of bacterial virulence of penicillin G and six macrolides against Streptococcus pneumoniae.

    OpenAIRE

    Fuursted, K.; Knudsen, J D; Petersen, M B; Poulsen, R L; Rehm, D

    1997-01-01

    In this report, we present MIC, bactericidal activity, postantibiotic effect (PAE), and in vivo infectivity data for postantibiotic-phase pneumococci. We compared and evaluated penicillin G and six macrolides, erythromycin, azithromycin, clarithromycin, dirithromycin, roxithromycin, and spiramycin, against 10 strains of pneumococci with various levels of susceptibility to penicillin. All of the agents, except azithromycin, exhibited a bactericidal effect (a > or = 3 log10 decrease in the numb...

  10. Age-Dependent Neisseria meningitidis Serogroup C Class-Specific Antibody Concentrations and Bactericidal Titers in Sera from Young Children from Montana Immunized with a Licensed Polysaccharide Vaccine

    OpenAIRE

    Maslanka, Susan E; Tappero, Jordan W.; Plikaytis, Brian D.; Brumberg, Robert S.; Dykes, Janet K.; Gheesling, Linda L.; Donaldson, Kimberley B. J.; Schuchat, Anne; Pullman, John; Jones, Maryann; Bushmaker, Julie; Carlone, George M.

    1998-01-01

    Neisseria meningitidis serogroup C bactericidal titers and class-specific enzyme-linked immunosorbent assay (ELISA) antibody concentrations were measured in sera from 173 children (1 to 5 years old) before and 6 weeks and 7 months following vaccination with a quadrivalent (A/C/Y/W-135) polysaccharide vaccine. The immune responses of the children were compared with those of 40 adults 6 weeks postvaccination. Both bactericidal titers and ELISA antibody concentrations were significantly higher i...

  11. Neutrophil bactericidal activity against Staphylococcus aureus adherent on biological surfaces. Surface-bound extracellular matrix proteins activate intracellular killing by oxygen-dependent and -independent mechanisms.

    OpenAIRE

    Hermann, M.; Jaconi, M E; Dahlgren, C; Waldvogel, F A; Stendahl, O; Lew, D P

    1990-01-01

    The activation patterns of surface adherent neutrophils are modulated via interaction of extracellular matrix proteins with neutrophil integrins. To evaluate neutrophil bactericidal activity, Staphylococcus aureus adherent to biological surfaces were incubated with neutrophils and serum, and the survival of surface bacteria was determined. When compared to albumin-coated surfaces, the bactericidal activity of neutrophils adherent to purified human extracellular matrix was markedly enhanced (m...

  12. Enhanced bactericidal potency of nanoliposomes by modification of the fusion activity between liposomes and bacterium

    Directory of Open Access Journals (Sweden)

    Ma YF

    2013-06-01

    amount of negative charges in fluid liposomes reduces fluid liposomes-bacteria fusion when tested without calcium cations due to electric repulsion, but addition of calcium cations brings the fusion level of fluid liposomes to similar or higher levels. Among the negative phospholipids examined, DMPA gave the highest degree of fusion, DMPS and DMPG had intermediate fusion levels, and PI resulted in the lowest degree of fusion. Furthermore, the fluid liposomal encapsulated tobramycin was prepared, and the bactericidal effect occurred more quickly when bacteria were cultured with liposomal encapsulated tobramycin. Conclusion: The bactericidal potency of fluid liposomes is dramatically enhanced with respect to fusion ability when the fusogenic lipid, DOPE, is included. Regardless of changes in liposome composition, fluid liposomes-bacterium fusion is universally enhanced by calcium ions. The information obtained in this study will increase our understanding of fluid liposomal action mechanisms, and help in optimizing the new generation of fluid liposomal formulations for the treatment of pulmonary bacterial infections. Keywords: liposomes, fusion, bacteria, Pseudomonas aeruginosa, lipid composition

  13. Detection and characterisation of Complement protein activity in bovine milk by bactericidal sequestration assay.

    Science.gov (United States)

    Maye, Susan; Stanton, Catherine; Fitzgerald, Gerald F; Kelly, Philip M

    2015-08-01

    While the Complement protein system in human milk is well characterised, there is little information on its presence and activity in bovine milk. Complement forms part of the innate immune system, hence the importance of its contribution during milk ingestion to the overall defences of the neonate. A bactericidal sequestration assay, featuring a Complement sensitive strain, Escherichia coli 0111, originally used to characterise Complement activity in human milk was successfully applied to freshly drawn bovine milk samples, thus, providing an opportunity to compare Complement activities in both human and bovine milks. Although not identical in response, the levels of Complement activity in bovine milk were found to be closely comparable with that of human milk. Differential counts of Esch. coli 0111 after 2 h incubation were 6.20 and 6.06 log CFU/ml, for raw bovine and human milks, respectively - the lower value representing a stronger Complement response. Exposing bovine milk to a range of thermal treatments e.g. 42, 45, 65, 72, 85 or 95 °C for 10 min, progressively inhibited Complement activity by increasing temperature, thus confirming the heat labile nature of this immune protein system. Low level Complement activity was found, however, in 65 and 72 °C heat treated samples and in retailed pasteurised milk which highlights the outer limit to which high temperature, short time (HTST) industrial thermal processes should be applied if retention of activity is a priority. Concentration of Complement in the fat phase was evident following cream separation, and this was also reflected in the further loss of activity recorded in low fat variants of retailed pasteurised milk. Laboratory-based churning of the cream during simulated buttermaking generated an aqueous (buttermilk) phase with higher levels of Complement activity than the fat phase, thus pointing to a likely association with the milk fat globule membrane (MFGM) layer.

  14. [Role of reactive oxygen species in the bactericidal action of quinolones--inhibitors of DNA gyrase].

    Science.gov (United States)

    Kotova, V Iu; Mironov, A S; Zavigel'skiĭ, G B

    2014-01-01

    Quinolone antibiotics inhibit DNA gyrase, but the induced degradation of chromosomal DNA is determined by a complex process of joint action quinolones and hydroxyl radical OH'. To quantify the level of stress responses and their time dependence in bacterial cells the induced specific lux-biosensors--the bacterium Escherichia coli, containing hybrid plasmids pColD'::lux; pSoxS'::lux; pKatG'::lux were used in this study. It is shown that quinolones (nalidixic acid, norfloxacin) induce SOS-response and oxidative stress with the formation of superoxide anion O2(-) in E. coli cells. The main parameters of SOS-response and oxidative stress, which depend on the quinolone concentration, are determined. Formation of superoxide anion O2(-) occurs almost simultaneously with the SOS-response. The mutant strain of E. coli sodA sodB, which do not contain active forms of superoxide dismutases SodA and SodB, is characterized by an increased resistance to quinolones as compared to the wild type cells. At high concentrations of quinolones (nalidixic acid-->20 μg/mL; norfloxacin-->500 ng/mL) their bactericidal effect is partially caused by conversion of the superoxide anion to hydrogen peroxide H2O2, conducted by superoxide dismutases SodA and SodB, which is followed by the Fenton reaction and the formation of toxic hydroxyl radical OH'. At low concentrations of quinolones (nalidixic acid--<20 μg/mL; norfloxacin--<500 ng/mL), the role of active oxygen species in the antimicrobial effect is practically nonexistent.

  15. The bactericidal agent triclosan modulates thyroid hormone-associated gene expression and disrupts postembryonic anuran development

    Energy Technology Data Exchange (ETDEWEB)

    Veldhoen, Nik [Department of Biochemistry and Microbiology, P.O. Box 3055, Stn. CSC, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada); Skirrow, Rachel C. [Pacific Environmental Science Centre, 2645 Dollarton Highway, North Vancouver, British Columbia V7H 1V2 (Canada); Osachoff, Heather [Pacific Environmental Science Centre, 2645 Dollarton Highway, North Vancouver, British Columbia V7H 1V2 (Canada); Wigmore, Heidi [Pacific Environmental Science Centre, 2645 Dollarton Highway, North Vancouver, British Columbia V7H 1V2 (Canada); Clapson, David J. [Department of Biochemistry and Microbiology, P.O. Box 3055, Stn. CSC, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada); Gunderson, Mark P. [Department of Biochemistry and Microbiology, P.O. Box 3055, Stn. CSC, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada); Van Aggelen, Graham [Pacific Environmental Science Centre, 2645 Dollarton Highway, North Vancouver, British Columbia V7H 1V2 (Canada); Helbing, Caren C. [Department of Biochemistry and Microbiology, P.O. Box 3055, Stn. CSC, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada)]. E-mail: chelbing@uvic.ca

    2006-12-01

    We investigated whether exposure to environmentally relevant concentrations of the bactericidal agent, triclosan, induces changes in the thyroid hormone-mediated process of metamorphosis of the North American bullfrog, Rana catesbeiana and alters the expression profile of thyroid hormone receptor (TR) {alpha} and {beta}, basic transcription element binding protein (BTEB) and proliferating nuclear cell antigen (PCNA) gene transcripts. Premetamorphic tadpoles were immersed in environmentally relevant concentrations of triclosan and injected with 1 x 10{sup -11} mol/g body weight 3,5,3'-triiodothyronine (T{sub 3}) or vehicle control. Morphometric measurements and steady-state mRNA levels obtained by quantitative polymerase chain reaction were determined. mRNA abundance was also examined in Xenopus laevis XTC-2 cells treated with triclosan and/or 10 nM T{sub 3}. Tadpoles pretreated with triclosan concentrations as low as 0.15 {+-} 0.03 {mu}g/L for 4 days showed increased hindlimb development and a decrease in total body weight following T{sub 3} administration. Triclosan exposure also resulted in decreased T{sub 3}-mediated TR{beta} mRNA expression in the tadpole tail fin and increased levels of PCNA transcript in the brain within 48 h of T{sub 3} treatment whereas TR{alpha} and BTEB were unaffected. Triclosan alone altered thyroid hormone receptor {alpha} transcript levels in the brain of premetamorphic tadpoles and induced a transient weight loss. In XTC-2 cells, exposure to T{sub 3} plus nominal concentrations of triclosan as low as 0.03 {mu}g/L for 24 h resulted in altered thyroid hormone receptor mRNA expression. Exposure to low levels of triclosan disrupts thyroid hormone-associated gene expression and can alter the rate of thyroid hormone-mediated postembryonic anuran development.

  16. Exopolysaccharide dispelled by calcium hydroxide with volatile vehicles related to bactericidal effect for root canal medication

    Directory of Open Access Journals (Sweden)

    Lei Lei

    Full Text Available ABSTRACT Objective: Enterococcus faecalis is the dominant microbial species responsible for persistent apical periodontitis with ability to deeply penetrate into the dentin. Exopolysaccharides (EPS contribute to the pathogenicity and antibiotic resistance of E. faecalis. Our aim was to investigate the antimicrobial activity of calcium hydroxide (CH, camphorated parachlorophenol (CMCP, and chlorhexidine (CHX against E. faecalis in dentinal tubules. Material and Methods: Decoronated single-canal human teeth and semicylindrical dentin blocks were incubated with E. faecalis for 3 weeks. Samples were randomly assigned to six medication groups for 1 week (n=10 per group: CH + 40% glycerin-water solution (1:1, wt/vol; CMCP; 2% CHX; CH + CMCP (1:1, wt/vol; CH + CMCP (2:3, wt/vol; and saline. Bacterial samples were collected and assayed for colony-forming units. After dentin blocks were split longitudinally, confocal laser scanning microscopy was used to assess the proportion of viable bacteria and EPS production in dentin. Results: CMCP exhibited the best antimicrobial activity, while CH was the least sensitive against E. faecalis (p0.05. CH combined with CMCP inhibited EPS synthesis by E. faecalis, which sensitized biofilms to antibacterial substances. Moreover, increasing concentrations of CMCP decreased EPS matrix formation, which effectively sensitized biofilms to disinfection agents. Conclusion: The EPS matrix dispelled by CH paste with CMCP may be related to its bactericidal effect; the visualization and analysis of EPS formation and microbial colonization in dentin may be a useful approach to verify medicaments for antimicrobial therapy.

  17. The bactericidal effect of dendritic copper microparticles, contained in an alginate matrix, on Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Simon F Thomas

    Full Text Available Although the bactericidal effect of copper has been known for centuries, there is a current resurgence of interest in the use of this element as an antimicrobial agent. During this study the use of dendritic copper microparticles embedded in an alginate matrix as a rapid method for the deactivation of Escherichia coli ATCC 11775 was investigated. The copper/alginate produced a decrease in the minimum inhibitory concentration from free copper powder dispersed in the media from 0.25 to 0.065 mg/ml. Beads loaded with 4% Cu deactivated 99.97% of bacteria after 90 minutes, compared to a 44.2% reduction in viability in the equivalent free copper powder treatment. There was no observed loss in the efficacy of this method with increasing bacterial loading up to 10(6 cells/ml, however only 88.2% of E. coli were deactivated after 90 minutes at a loading of 10(8 cells/ml. The efficacy of this method was highly dependent on the oxygen content of the media, with a 4.01% increase in viable bacteria observed under anoxic conditions compared to a >99% reduction in bacterial viability in oxygen tensions above 50% of saturation. Scanning electron micrographs (SEM of the beads indicated that the dendritic copper particles sit as discrete clusters within a layered alginate matrix, and that the external surface of the beads has a scale-like appearance with dendritic copper particles extruding. E. coli cells visualised using SEM indicated a loss of cellular integrity upon Cu bead treatment with obvious visible blebbing. This study indicates the use of microscale dendritic particles of Cu embedded in an alginate matrix to effectively deactivate E. coli cells and opens the possibility of their application within effective water treatment processes, especially in high particulate waste streams where conventional methods, such as UV treatment or chlorination, are ineffective or inappropriate.

  18. Hydrophilic, bactericidal nanoheater-enabled reverse osmosis membranes to improve fouling resistance.

    Science.gov (United States)

    Ray, Jessica R; Tadepalli, Sirimuvva; Nergiz, Saide Z; Liu, Keng-Ku; You, Le; Tang, Yinjie; Singamaneni, Srikanth; Jun, Young-Shin

    2015-06-01

    Polyamide (PA) semipermeable membranes typically used for reverse osmosis water treatment processes are prone to fouling, which reduces the amount and quality of water produced. By synergistically coupling the photothermal and bactericidal properties of graphene oxide (GO) nanosheets, gold nanostars (AuNS), and hydrophilic polyethylene glycol (PEG) on PA reverse osmosis membrane surfaces, we have dramatically improved fouling resistance of these membranes. Batch fouling experiments from three classes of fouling are presented: mineral scaling (CaCO3 and CaSO4), organic fouling (humic acid), and biofouling (Escherichia coli). Systematic analyses and a variety of complementary techniques were used to elucidate fouling resistance mechanisms from each layer of modification on the membrane surface. Both mineral scaling and organic fouling were significantly reduced in PA-GO-AuNS-PEG membranes compared to other membranes. The PA-GO-AuNS-PEG membrane was also effective in killing all near-surface bacteria compared to PA membranes. In the PA-GO-AuNS-PEG membrane, the GO nanosheets act as templates for in situ AuNS growth, which then facilitated localized heating upon irradiation by an 808 nm laser inactivating bacteria on the membrane surface. Furthermore, AuNS in the membrane assisted PEG in preventing mineral scaling on the membrane surface. In flow-through flux and foulant rejection tests, PA-GO-AuNS-PEG membranes performed better than PA membranes in the presence of CaSO4 and humic acid model foulants. Therefore, the newly suggested membrane surface modifications will not only reduce fouling from RO feeds, but can improve overall membrane performance. Our innovative membrane design reported in this study can significantly extend the lifetime and water treatment efficacy of reverse osmosis membranes to alleviate escalating global water shortage from rising energy demands.

  19. The Bactericidal Effect of Dendritic Copper Microparticles, Contained in an Alginate Matrix, on Escherichia coli

    Science.gov (United States)

    Thomas, Simon F.; Rooks, Paul; Rudin, Fabian; Atkinson, Sov; Goddard, Paul; Bransgrove, Rachel; Mason, Paul T.; Allen, Michael J.

    2014-01-01

    Although the bactericidal effect of copper has been known for centuries, there is a current resurgence of interest in the use of this element as an antimicrobial agent. During this study the use of dendritic copper microparticles embedded in an alginate matrix as a rapid method for the deactivation of Escherichia coli ATCC 11775 was investigated. The copper/alginate produced a decrease in the minimum inhibitory concentration from free copper powder dispersed in the media from 0.25 to 0.065 mg/ml. Beads loaded with 4% Cu deactivated 99.97% of bacteria after 90 minutes, compared to a 44.2% reduction in viability in the equivalent free copper powder treatment. There was no observed loss in the efficacy of this method with increasing bacterial loading up to 106 cells/ml, however only 88.2% of E. coli were deactivated after 90 minutes at a loading of 108 cells/ml. The efficacy of this method was highly dependent on the oxygen content of the media, with a 4.01% increase in viable bacteria observed under anoxic conditions compared to a >99% reduction in bacterial viability in oxygen tensions above 50% of saturation. Scanning electron micrographs (SEM) of the beads indicated that the dendritic copper particles sit as discrete clusters within a layered alginate matrix, and that the external surface of the beads has a scale-like appearance with dendritic copper particles extruding. E. coli cells visualised using SEM indicated a loss of cellular integrity upon Cu bead treatment with obvious visible blebbing. This study indicates the use of microscale dendritic particles of Cu embedded in an alginate matrix to effectively deactivate E. coli cells and opens the possibility of their application within effective water treatment processes, especially in high particulate waste streams where conventional methods, such as UV treatment or chlorination, are ineffective or inappropriate. PMID:24831035

  20. IPN hydrogel nanocomposites based on agarose and ZnO with antifouling and bactericidal properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingjing, E-mail: jjwang1@hotmail.com; Hu, Hongkai; Yang, Zhonglin; Wei, Jun; Li, Juan

    2016-04-01

    Nanocomposite hydrogels with interpenetrating polymer network (IPN) structure based on poly(ethylene glycol) methyl ether methacrylate modified ZnO (ZnO-PEGMA) and 4-azidobenzoic agarose (AG-N{sub 3}) were prepared by a one-pot strategy under UV irradiation. The hydrogels exhibited a highly macroporous spongelike structure, and the pore size decreased with the increase of the ZnO-PEGMA content. Due to the entanglement and favorable interactions between the two crosslinked networks, the IPN hydrogels exhibited excellent mechanical strength and light transmittance. The maximum compressive and tensile strengths of the IPN hydrogels reached 24.8 and 1.98 MPa respectively. The transparent IPN hydrogels transmitted more than 85% of visible light at all wavelengths (400–800 nm). The IPN hydrogels exhibited anti-adhesive property towards Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), and the bactericidal activity increased with the ZnO-PEGMA content. The incorporation of ZnO-PEGMA did not reduce the biocompatibility of the IPN hydrogels and all the IPN nanocomposites showed negligible cytotoxicity. The present study not only provided a facile method for preparing hydrogel nanocomposites with IPN structure but also developed a new hydrogel material which might be an excellent candidate for wound dressings. - Highlights: • IPN hydrogel nanocomposites were prepared by a one-pot strategy. • The maximum compressive and tensile strengths reached 24.8 and 1.98 MPa. • IPN hydrogels displayed excellent antibacterial activity and cytocompatibility. • This study provided a facile method for preparing IPN hydrogel nanocomposites.

  1. Immobilized silver nanoparticles enhance contact killing and show highest efficacy: elucidation of the mechanism of bactericidal action of silver

    Science.gov (United States)

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-07-01

    Antimicrobial materials with immobilized/entrapped silver nanoparticles (AgNPs) are of considerable interest. There is significant debate on the mode of bactericidal action of AgNPs, and both contact killing and/or ion mediated killing have been proposed. In this study, AgNPs were immobilized on an amine-functionalized silica surface and their bactericidal activity was studied concurrently with the silver release profile over time. This was compared with similar studies performed using colloidal AgNPs and AgCl surfaces that released Ag ions. We conclude that contact killing is the predominant bactericidal mechanism and surface immobilized nanoparticles show greater efficacy than colloidal AgNPs, as well as a higher concentration of silver ions in solution. In addition, the AgNP immobilized substrate was used multiple times with good efficacy, indicating this immobilization protocol is effective for retaining AgNPs while maintaining their disinfection potential. The antibacterial surface was found to be extremely stable in aqueous medium and no significant leaching (~1.15% of total silver deposited) of the AgNPs was observed. Thus, immobilization of AgNPs on a surface may promote reuse, reduce environmental risks associated with leaching of AgNPs and enhance cost effectiveness.Antimicrobial materials with immobilized/entrapped silver nanoparticles (AgNPs) are of considerable interest. There is significant debate on the mode of bactericidal action of AgNPs, and both contact killing and/or ion mediated killing have been proposed. In this study, AgNPs were immobilized on an amine-functionalized silica surface and their bactericidal activity was studied concurrently with the silver release profile over time. This was compared with similar studies performed using colloidal AgNPs and AgCl surfaces that released Ag ions. We conclude that contact killing is the predominant bactericidal mechanism and surface immobilized nanoparticles show greater efficacy than colloidal Ag

  2. Killing of gram-negative bacteria by polymorphonuclear leukocytes: role of an O2-independent bactericidal system.

    Science.gov (United States)

    Weiss, J; Victor, M; Stendhal, O; Elsbach, P

    1982-04-01

    Previous studies have suggested that a cationic bactericidal/permeability-increasing protein (BPI) present in both rabbit and human polymorphonuclear leukocytes is the principal O2-independent bactericidal agent of these cells toward several strains of Escherichia coli and Salmonella typhimurium (1978. J. Biol. Chem. 253: 2664--2672; 1979. J. Biol. Chem. 254: 11000--11009). To further evaluate the possible role of this protein in the killing of gram-negative bacteria by polymorphonuclear leukocytes, we have measured the bactericidal activity of intact rabbit peritoneal exudate leukocytes under aerobic or anaerobic conditions and of intact human leukocytes from a patient with chronic granulomatous disease. Anaerobic conditions were created by flushing the cells under a nitrogen stream. Effective removal of oxygen was demonstrated by the inability of nitrogen-flushed leukocytes to mount a respiratory burst (measured as increased conversion of 1-[14C]glucose leads to 14CO2 or by superoxide production) during bacterial ingestion. At a bacteria/leukocyte ratio of 10:1, killing of gram-positive, BPI-resistant, Staphylococcus epidermidis is markedly impaired in the absence of oxygen (76.4 +/- 3.3% killing in room air, 29.2 +/- 8.2% killing in nitrogen). Essentially all increased bacterial survival is intracellular. In contrast, both a nonopsonized rough strain (MR-10) and an opsonized smooth strain (MS) of S. typhimurium 395 are killed equally well in room air and nitrogen. A maximum of 70--80 MR-10 and 30--40 MS are killed per leukocyte either in the presence or absence of oxygen. There is no intracellular bacterial survival in either condition indicating that intracellular O2-independent bactericidal system(s) of rabbit polymorphonuclear leukocytes can at least match the leukocyte's ingestive capacity. Whole homogenates and crude acid extracts manifest similar bactericidal capacity toward S. typhimurium 395. This activity can be accounted for by the BPI content of these

  3. Algerian propolis extracts: Chemical composition, bactericidal activity and in vitro effects on gilthead seabream innate immune responses.

    Science.gov (United States)

    Soltani, El-Khamsa; Cerezuela, Rebeca; Charef, Noureddine; Mezaache-Aichour, Samia; Esteban, Maria Angeles; Zerroug, Mohamed Mihoub

    2017-03-01

    Propolis has been used as a medicinal agent for centuries. The chemical composition of four propolis samples collected from four locations of the Sétif region, Algeria, using gas chromatography-mass spectrometry was determined. More than 20 compounds and from 30 to 35 compounds were identified in the aqueous and ethanolic extracts, respectively. Furthermore, the antimicrobial activity of the propolis extracts against two marine pathogenic bacteria was evaluated. Finally, the in vitro effects of propolis on gilthead seabream (Sparus aurata L.) leucocyte activities were measured. The bactericidal activity of ethanolic extracts was very high against Shewanella putrefaciens, average against Photobacterium damselae and very low against Vibrio harveyi. The lowest bactericidal activity was always that found for the aqueous extracts. When the viability of gilthead seabream head-kidney leucocytes was measured after 30 min' incubation with the different extracts, both the ethanolic and aqueous extracts of one of the propolis samples (from Babor) and the aqueous extract of another (from Ain-Abbassa) provoked a significant decrease in cell viability when used at concentrations of 100 and 200 μg ml(-1). Furthermore, significant inhibitory effects were recorded on leucocyte respiratory burst activity when isolated leucocytes where preincubated with the extracts. This effect was dose-dependent in all cases except when extracts from a third propolis sample (from Boutaleb) were used. Our findings suggest that some of Algerian propolis extracts have bactericidal activity against important bacterial pathogens in seabream and significantly modulate in vitro leucocyte activities, confirming their potential as a source of new natural biocides and/or immunomodulators in aquaculture practice.

  4. Biofilm-forming activity of bacteria isolated from toilet bowl biofilms and the bactericidal activity of disinfectants against the isolates.

    Science.gov (United States)

    Mori, Miho; Gomi, Mitsuhiro; Matsumune, Norihiko; Niizeki, Kazuma; Sakagami, Yoshikazu

    2013-01-01

    To evaluate the sanitary conditions of toilets, the bacterial counts of the toilet bowl biofilms in 5 Kansai area and 11 Kansai and Kanto area homes in Japan were measured in winter and summer seasons, respectively. Isolates (128 strains) were identified by analyzing 16S ribosomal RNA sequences. The number of colonies and bacterial species from biofilms sampled in winter tended to be higher and lower, respectively, than those in summer. Moreover, the composition of bacterial communities in summer and winter samples differed considerably. In summer samples, biofilms in Kansai and Kanto areas were dominated by Blastomonas sp. and Mycobacterium sp., respectively. Methylobacterium sp. was detected in all toilet bowl biofilms except for one sample. Methylobacterium sp. constituted the major presence in biofilms along with Brevundimonas sp., Sphingomonas sp., and/or Pseudomonas sp. The composition ratio of the sum of their genera was 88.0 from 42.9% of the total bacterial flora. The biofilm formation abilities of 128 isolates were investigated, and results suggested that Methylobacterium sp. and Sphingomonas sp. were involved in biofilm formation in toilet bowls. The biofilm formation of a mixed bacteria system that included bacteria with the highest biofilm-forming ability in a winter sample was greater than mixture without such bacteria. This result suggests that isolates possessing a high biofilm-forming activity are involved in the biofilm formation in the actual toilet bowl. A bactericidal test against 25 strains indicated that the bactericidal activities of didecyldimethylammonium chloride (DDAC) tended to be higher than those of polyhexamethylene biguanide (PHMB) and N-benzyl-N,N-dimethyldodecylammonium chloride (ADBAC). In particular, DDAC showed high bactericidal activity against approximately 90% of tested strains under the 5 h treatment.

  5. Spectrophotometric Screening of Potent Bactericidal Property of Thevetia Peruviana Schum. Leaf and Fruit Rind Extracts on Clinical and Plant Pathogens

    Directory of Open Access Journals (Sweden)

    Nazneen Rahman

    2014-12-01

    Full Text Available The development of multi drug resistance in human and plant pathogens, reconsidering the traditional medicines as antibacterial source and presence of promising phytochemicals in leaf and fruit rind of T. peruviana (S (Nazneen et al., 2014 prompted the authors to take up the antibacterial evaluation of different extracts. Antibacterial activity, minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC of various extracts of T. peruviana (S were measured using methods of National Committee for Clinical Laboratory Standards (NCCLS. The minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC spectrophotometric determination of active extracts has found that the MICs of all the active extracts lies between the range of 250 μg to 1250 μg and bactericidal concentration in a range of 500 to 1250 μg. The percentage of inhibition was analysed, where in among all the extracts tested against B. subtilis and E. coli, fruit upper liquid (FUL exhibited highest inhibition percentage of 33.75% and 30.31 % at 500 μg/ml respectively. Similarly, fruit hexane (FH extract has the highest inhibition of 15.60% against B. cereus at 750 μg/ml. The Xanthomonas sp. was susceptible to leaf chloroform (LC with 32.29% of inhibition at 1000 μg/ ml. The activity index and total antimicrobial activity indicates the antibacterial action of extracts. The present investigations have revealed that among the extracts, the fruit rind extracts have most prominent inhibition abilities against tested bacteria, which are validating the use of this plant in traditional system of medicine and this is the first report of exploration of above extracts for their antibacterial activities against B. subtilis, B. cereus, E. coli and Xanthomonas sp.

  6. Blood neutrophil bactericidal activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus during cardiac surgery.

    Science.gov (United States)

    Mekontso-Dessap, Armand; Honoré, Stéphanie; Kirsch, Matthias; Plonquet, Anne; Fernandez, Eric; Touqui, Lhousseine; Farcet, Jean-Pierre; Soussy, Claude-James; Loisance, Daniel; Delclaux, Christophe

    2005-08-01

    Whether methicillin-resistant Staphylococcus aureus (MRSA) constitutes per se an independent risk factor for morbidity and mortality after surgery as compared with methicillin-sensitive Staphylococcus aureus (MSSA) remains a subject of debate. The aim of this study was to assess whether innate defenses against MRSA and MSSA strains are similarly impaired after cardiac surgery. Both intracellular (isolated neutrophil functions) and extracellular (plasma) defenses of 12 patients undergoing scheduled cardiac surgery were evaluated preoperatively (day 0) and postoperatively (day 3) against two MSSA strains with a low level of catalase secretion and two MRSA strains with a high level of catalase secretion, inasmuch as SA killing by neutrophils relies on oxygen-dependent mechanisms. After surgery, an increase in plasma concentration of IL-10, an anti-inflammatory cytokine able to inhibit reactive oxygen species secretion and bactericidal activity of neutrophils, was evidenced. Despite the fact that univariate analysis suggested a specific impairment of neutrophil functions against MRSA strains, two-way repeated-measures ANOVA failed to demonstrate that the effect of S. aureus phenotype was significant. On the other hand, an increase in type-II secretory phospholipase A2 activity, a circulating enzyme involved in SA lysis, was evidenced and was associated with an enhancement of extracellular defenses (bactericidal activity of plasma) against MRSA. Overall, cardiac surgery and S. aureus phenotype had a significant effect on plasma bactericidal activity. Cardiac surgery was characterized by enhanced antibacterial defenses of plasma, whereas neutrophil killing properties were reduced. The overall effect of S. aureus phenotype on neutrophil functions did not seem significant.

  7. Effect of food processing organic matter on photocatalytic bactericidal activity of titanium dioxide (TiO2).

    Science.gov (United States)

    Yemmireddy, Veerachandra K; Hung, Yen-Con

    2015-07-02

    The purpose of this study was to determine the effect of food processing organic matter on photocatalytic bactericidal activity of titanium dioxide (TiO2) nanoparticles (NPs). Produce and meat processing wash solutions were prepared using romaine lettuce and ground beef samples. Physico-chemical properties such as pH, turbidity, chemical oxygen demand (COD), total phenolics (for produce) and protein (for meat) content of the extracts were determined using standard procedures. The photocatalytic bactericidal activity of TiO2 (1 mg/mL) in suspension with or without organic matter against Escherichia coli O157:H7 (5-strain) was determined over a period of 3h. Increasing the concentration of organic matter (either produce or meat) from 0% to 100% resulted in 85% decrease in TiO2 microbicidal efficacy. 'Turbidity, total phenolics, and protein contents in wash solutions had significant effect on the log reduction. Increasing the total phenolics content in produce washes from 20 to 114 mg/L decreased the log reduction from 2.7 to 0.38 CFU/mL, whereas increasing the protein content in meat washes from 0.12 to 1.61 mg/L decreased the log reduction from and 5.74 to 0.87 CFU/mL. Also, a linear correlation was observed between COD and total phenolics as well as COD and protein contents. While classical disinfection kinetic models failed to predict, an empirical equation in the form of "Y=me(nX)" (where Y is log reduction, X is COD, and m and n are reaction rate constants) predicted the disinfection kinetics of TiO2 in the presence of organic matter (R(2)=94.4). This study successfully identified an empirical model with COD as a predictor variable to predict the bactericidal efficacy of TiO2 when used in food processing environment.

  8. Glycolic acid chemical peeling improves inflammatory acne eruptions through its inhibitory and bactericidal effects on Propionibacterium acnes.

    Science.gov (United States)

    Takenaka, Yuko; Hayashi, Nobukazu; Takeda, Mikiko; Ashikaga, Sayaka; Kawashima, Makoto

    2012-04-01

    Glycolic acid chemical peeling is effective for treating comedones, and some clinical data show that it also improves inflammatory eruptions. The purpose of this study was to identify the mechanism of glycolic acid chemical peeling to improve inflammatory acne. To assess growth inhibitory and bactericidal effects of glycolic acid on Propionibacterium acnes in vitro, we used an agar diffusion method and a time-kill method. To reveal bactericidal effects in vivo, we established an agar-attached method which correlated well with the ordinary swab-wash method, and we used the agar-attached method to compare the numbers of propionibacteria on the cheek treated with glycolic acid chemical peeling. Our results show that 30% glycolic acid (at pH 1.5, 3.5 and 5.5) formed growth inhibitory circles in the agar diffusion method, but the diameters of those circles were smaller than with 1% nadifloxacin lotion or 1% clindamycin gel. In the time-kill method, 30% glycolic acid (at pH 1.5 and 3.5) or 1% nadifloxacin lotion reduced the number of P. acnes to less than 100 CFU/mL within 5 min. In contrast, in 30% glycolic acid (at pH 5.5) or in 1% clindamycin gel, P. acnes survived for more than 4 h. Chemical peeling with 35% glycolic acid (at pH 1.2) decreased the number of propionibacteria on the cheeks of patients compared with untreated controls (P glycolic acid has moderate growth inhibitory and bactericidal effects on P. acnes, and that chemical peeling with glycolic acid works on inflammatory acne via those effects.

  9. [Tests on the bactericidal effectiveness of iodophor A in the halls of a pig-fattening station].

    Science.gov (United States)

    Kubícek, K

    1975-04-01

    In the halls of the pig fattening house the bactericidal effectiveness of cold water solutions of Czechoslovakia-made Jodofor A and the product of the Ciba-Geigy company Iosan was tested and compared with the effectiveness of Chloramin B used in a water solution at the temperature of 50 to 60 degrees C. The solutions were applied by fine spraying at the rate of 0.5 lt. per 1 m2 of area. After one hour the spray was applied again at the same rate. One hour after the last Jodofor spray and two hours after the last Chloramin B spray, smears were collected from the disinfected surfaces. The examination included the detection of coliform germs, germs of the Micrococcaceae family, and the determination of the total number of germs. On the whole, 384 smears were examined in four separate trials. The application of Jodofor A in 2% concentrations, after mechanical average-quality purification, did not give acceptable results, in comparison with the solution of Cloramin B. Only when solutions of Jodofor A and Iosan were used in 3% concentration after perfect mechanical purification, satisfactory results were obtained (with the exception of plaster and painted wood), in comparison with the Chloramin B solution. Better disinfectibility was found in aluminium sheet, terracotta, concrete, and metal, as distinct from plaster and painted wood. The comparison of Jodofor A with abroad-male Iosan indicates that Jodofor has the same or a better bactericidal effect than Iosan in all indices. Due to its bactericidal effect, Jodofor A is a suitable disinfectant for preventive disinfection of farm animal houses. In order to achieve results corresponding to those provided by 2% solutions of Chloramin B it is necessary to use at least 3% concentration of Jodofor A. Good mechanical purification is a basic prerequisite for its effectiveness.

  10. Bactericidal effect of colistin on planktonic Pseudomonas aeruginosa is independent of hydroxyl radical formation

    DEFF Research Database (Denmark)

    Brochmann, Rikke Prejh; Toft, Anders; Ciofu, Oana;

    2014-01-01

    The bactericidal effect of several major types of antibiotics has recently been demonstrated to be dependent on the formation of toxic amounts of hydroxyl radicals (OH·) resulting from oxidative stress in metabolically active cells. Since killing by the antimicrobial peptide colistin does not req......, antimicrobial peptides that do not rely on OH· formation should be considered for treatment of Gram-negative bacteria growing at low oxygen tension such as in endobronchial mucus and paranasal sinuses in cystic fibrosis patients, in abscesses and in infectious biofilm....

  11. Bactericidal activity does not predict sterilizing activity: the case of rifapentine in the murine model of Mycobacterium ulcerans disease.

    Directory of Open Access Journals (Sweden)

    Deepak V Almeida

    Full Text Available BACKGROUND: Since 2004, treatment of Mycobacterium ulcerans disease, or Buruli ulcer, has shifted from surgery to daily treatment with streptomycin (STR + rifampin (RIF for 8 weeks. For shortening treatment duration, we tested the potential of daily rifapentine (RPT, a long-acting rifamycin derivative, as a substitute for RIF. METHODOLOGY/PRINCIPAL FINDINGS: BALB/c mice were infected with M. ulcerans in the right hind footpad and treated either daily (7/7 with STR+RIF or five days/week (5/7 with STR+RIF or STR+RPT for 4 weeks, beginning 28 days after infection when CFU counts were 4.88±0.51. The relative efficacy of the drug treatments was compared by footpad CFU counts during treatment and median time to footpad swelling after treatment cessation as measure of sterilizing activity. All drug treatments were bactericidal. After 1 week of treatment, the decline in CFU counts was significantly greater in treated mice but not different between the three treated groups. After 2 weeks of treatment, the decline in CFU was greater in mice treated with STR+RPT 5/7 than in mice treated with STR+RIF 7/7 and STR+RIF 5/7. After 3 and 4 weeks of treatment, CFU counts were nil in mice treated with STR+RPT and reduced by more than 3 and 4 logs in mice treated with STR+RIF 5/7 and STR+RIF 7/7, respectively. In sharp contrast to the bactericidal activity, the sterilizing activity was not different between all drug regimens although it was in proportion to the treatment duration. CONCLUSIONS/SIGNIFICANCE: The better bactericidal activity of daily STR+RIF and especially of STR+RPT did not translate into better prevention of relapse, possibly because relapse-freecure after treatment of Buruli ulcer is more related to the reversal of mycolactone-induced local immunodeficiency by drug treatment rather than to the bactericidal potency of drugs.

  12. Cerebrospinal fluid bactericidal activity against cephalosporin-resistant Streptococcus pneumoniae in children with meningitis treated with high-dosage cefotaxime.

    OpenAIRE

    1997-01-01

    We determined cefotaxime and desacetyl-cefotaxime concentrations in children with bacterial meningitis receiving high-dose cefotaxime (300 mg/kg of body weight/day) and concomitant dexamethasone therapy. The median peak cerebrospinal fluid cefotaxime and desacetyl-cefotaxime concentrations were 4.7 and 8.1 microg/ml, respectively. In vitro bactericidal activity (>99.9% killing in 6 h) was found in 17 (94%), 13 (72%), and 8 (44%) of 18 cerebrospinal fluid specimens against cefotaxime-susceptib...

  13. Bactericide Effect of Silver Nanoparticles as a Final Irrigation Agent in Endodontics on Enterococcus faecalis: An Ex Vivo Study

    OpenAIRE

    Pedro-IV González-Luna; Gabriel-Alejandro Martínez-Castañón; Norma-Verónica Zavala-Alonso; Nuria Patiño-Marin; Nereyda Niño-Martínez; Javier Morán-Martínez; Jorge-Humberto Ramírez-González

    2016-01-01

    The objective of this study was to determine the bactericidal effect of silver nanoparticles as a final irrigation agent in endodontics. This study included 120 uniradicular extracted dental organs inoculated with Enterococcus faecalis (E. faecalis) and organized into 4 groups: (A) 30 teeth irrigated with a dispersion of silver nanoparticles (537 μg/mL); (B) 30 teeth irrigated with a sodium hypochlorite solution (2.25%); (C) 30 teeth irrigated with a dispersion of silver nanoparticles (537 μg...

  14. Efficacy of pH elevation as a bactericidal strategy for treating ballast water of freight carriers

    Directory of Open Access Journals (Sweden)

    Clifford E. Starliper

    2015-05-01

    Full Text Available Treatment of ship ballast water with sodium hydroxide (NaOH is one method currently being developed to minimize the risk to introduce aquatic invasive species. The bactericidal capability of sodium hydroxide was determined for 148 bacterial strains from ballast water collected in 2009 and 2010 from the M/V Indiana Harbor, a bulk-freight carrier plying the Laurentian Great Lakes, USA. Primary culture of bacteria was done using brain heart infusion agar and a developmental medium. Strains were characterized based on PCR amplification and sequencing of a portion of the 16S rRNA gene. Sequence similarities (99+ % were determined by comparison with the National Center for Biotechnology Information (NCBI GenBank catalog. Flavobacterium spp. were the most prevalent bacteria characterized in 2009, comprising 51.1% (24/47 of the total, and Pseudomonas spp. (62/101; 61.4% and Brevundimonas spp. (22/101; 21.8% were the predominate bacteria recovered in 2010; together, comprising 83.2% (84/101 of the total. Testing was done in tryptic soy broth (TSB medium adjusted with 5 N NaOH. Growth of each strain was evaluated at pH 10.0, pH 11.0 and pH 12.0, and 4 h up to 72 h. The median cell count at 0 h for 148 cultures was 5.20 × 106 cfu/mL with a range 1.02 × 105–1.60 × 108 cfu/mL. The TSB adjusted to pH 10.0 and incubation for less than 24 h was bactericidal to 52 (35.1% strains. Growth in pH 11.0 TSB for less than 4 h was bactericidal to 131 (88.5% strains and pH 11.0 within 12 h was bactericidal to 141 (95.3%. One strain, Bacillus horikoshii, survived the harshest treatment, pH 12.0 for 72 h.

  15. Immunoregulation by macrophages II. Separation of mouse peritoneal macrophages having tumoricidal and bactericidal activities and those secreting PGE and interleukin I

    Energy Technology Data Exchange (ETDEWEB)

    Hopper, K.E.; Cahill, J.M.

    1983-06-01

    Macrophage subpopulations having bactericidal or tumoricidal activities and secreting interleukin I (IL1) or prostaglandin E (PGE) were identified through primary or secondary infection with Salmonella enteritidis and separated by sedimentation velocity. Bactericidal activity was measured by (3H)-thymidine release from Listeria monocytogenes and tumoricidal activity by 51Cr-release from C-4 fibrosarcoma or P815 mastocytoma cells. Macrophages with bactericidal activity were distinguished from those with tumoricidal activity a) during secondary infection when cytolytic activity occurred only at days 1-4 post injection and bactericidal activity remained high throughout and b) after sedimentation velocity separation. Cytolysis was consistently greatest among adherent cells of low sedimentation velocity, whereas cells with bactericidal activity increased in size during the infection. Tumour cytostasis (inhibition and promotion of (3H)-thymidine uptake) differed from cytolysis in that the former was more prolonged during infection and was also detected among large cells. Secretion of immunoregulatory molecules PGE and IL1 occurred maximally among different macrophage subpopulations separated by sedimentation velocity and depending on the type of stimulus used in vitro. There was an inverse correlation between IL1 production and PGE production after stimulation with C3-zymosan or lipopolysaccharide (LPS). The development of immunity during infection may therefore be dependent upon the relative proportions of effector and regulatory macrophage subpopulations and the selective effects of environmental stimuli on these functions.

  16. Subsets of memory CD4+ T cell and bactericidal antibody response to Neisseria meningitidis serogroup C after immunization of HIV-infected children and adolescents.

    Directory of Open Access Journals (Sweden)

    Lucimar G Milagres

    Full Text Available Meningococcal disease is endemic in Brazil, with periodic outbreaks and case fatality rates reach as high as 18 to 20% of cases. Conjugate vaccines against meningococci are immunogenic in healthy children. However, we have previously shown a poor bactericidal antibody response to a Men C conjugate vaccine in Brazilian HIV-infected children and adolescents after a single vaccine administration. The goal of the present work was to investigate associations between bactericidal antibody response induced by MenC vaccine and the frequency and activation profile (expression of CD38, HLA-DR and CCR5 molecules of total CD4+ memory T cell sub-populations in HIV-1-infected children and adolescents. Responders to vaccination against MenC had a predominance (about 44% of CD4+ TINTERMEDIATE subset followed by TTRANSITIONAL memory subset (23 to 26%. Importantly, CD4+ TINT frequency was positively associated with bactericidal antibody response induced by vaccination. The positive correlation persisted despite the observation that the frequency TINT CD38+HLA-DR+ was higher in responders. In contrast, CD4+ TCENTRAL MEMORY (TCM subset negatively correlated with bactericidal antibodies. In conclusion, these data indicate that less differentiated CD+ T cells, like TCM may be constantly differentiating into intermediate and later differentiated CD4+ T cell subsets. These include CD4 TINT subset which showed a positive association with bactericidal antibodies.

  17. Bactericidal efficiency and mode of action: a comparative study of photochemistry and photocatalysis.

    Science.gov (United States)

    Pigeot-Rémy, S; Simonet, F; Atlan, D; Lazzaroni, J C; Guillard, C

    2012-06-15

    In order to compare the disinfection potential of photocatalysis and photochemistry, the effects of these two processes on bacteria in water were investigated under exposure to UV-A and UV-C. The well-known bacterial model Escherichia coli (E. coli) was used as the experimental organism. Radiation exposure was produced with an HPK 125 W lamp and the standard TiO(2) Degussa P-25 was used as the photocatalyst. Firstly, the impact of photocatalysis and photochemistry on the cultivability of bacterial cells was investigated. UV-A radiation resulted in low deleterious effects on bacterial cultivability but generated colonies of size smaller than average. UV-C photocatalysis demonstrated a greater efficiency than UV-A photocatalysis in altering bacterial cultivability. From a cultivability point of view only, UV-C radiation appeared to be the most deleterious treatment. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit was then used to assess the modifications in bacterial membrane permeability. UV-A radiation did not induce any alterations in bacterial permeability for 420 min of exposure whereas only a few minutes of exposure to UV-C radiation, with the same total radiance intensity, induced total loss of permeability. Moreover, after 20 and 60 min of exposure to UV-C and UV-A photocatalysis respectively, all bacteria lost their membrane integrity, suggesting that the bacterial envelope is the primary target of reactive oxygen species (ROS) generated at the surface of TiO(2) photocatalyst. These results were further confirmed by the formation of malondialdehyde (MDA) during the photocatalytic inactivation of bacterial cells and suggest that destruction of the cell envelope is a key step in the bactericidal action of photocatalysis. The oxidation of bacterial membrane lipids was also correlated with the monitoring of carboxylic acids, which can be considered as representatives of lipid peroxidation by-products. Finally, damages to

  18. Synthesis of bactericide Cyprodinil%杀菌剂嘧菌环胺的合成

    Institute of Scientific and Technical Information of China (English)

    瞿佳; 蔡鹏; 来虎钦; 李风月; 苗丽

    2012-01-01

    以环丙甲酮、乙酸乙酯、苯基胍碳酸盐为原料,经缩合、环合两步反应得到杀菌剂嘧菌环胺.考察了各步反应的溶剂选择、反应温度、反应时间、原料配比等因素对反应收率的影响.结果表明:缩合反应的较佳条件为:异丙醚作溶剂,n(环丙甲酮)∶n(金属钠)∶n(乙酸乙酯)=1∶1.3∶1.5,反应温度65℃,反应时间3h;环合反应的较佳条件为:甲苯作溶剂,n(1-环丙基-1,3丁二酮)∶n(苯基胍碳酸盐)=1∶0.7,反应温度110℃,反应时间3h.反应总收率达到76.3%,含量94.5%.产品及其中间体结构经1 H NMR和IR确证.%Using cyclopropyl methyl ketone? Ethyl acetate and phenylguanidine carbonate salt as raw materials, the bactericide Cyprodinil was prepared through the successive reactions of condensation and cyclization. The influences of solvent, temperature, time and molar ratio of materials were investigated. The optimum synthetic conditions were as follows: The condensation reaction solvent was isopropyl ether, n(cyclopropyl methyl ketone) : n(sodium) : n (ethyl acetate) = 1 : 1. 3 : 1. 5, reaction temperature was 65 ℃, reaction time was 3 h. The cyclization reaction solvent reaction was methylbenzene, n(l-cyclopropyl-l, 3-butanedione) '? N (phenylguanidine carbonate salt) = 1 : 0. 7, reaction temperature was 110 ℃ , reaction time was 3 h. The overall yield of Cyprodinil was 72. 4% with the purity of 96. 1%. The structures of the product and the intermediate were characterized by 1H NMR and IR.

  19. Effect of organically modified clay on mechanical properties, cytotoxicity and bactericidal properties of poly(ɛ-caprolactone) nanocomposites

    Science.gov (United States)

    Kumar, Sachin; Mishra, Anupam; Chatterjee, Kaushik

    2014-12-01

    The objective of this study was to evaluate the use of organically-modified clay nanoparticles in poly(ɛ-caprolactone) (PCL) for developing biodegradable composites. PCL nanocomposites reinforced with two different types of organically-modified clay (Cloisite 30B, C30B and Cloisite 93A, C93A) were prepared by melt-mixing. Morphology of PCL/clay nanocomposites characterized by scanning electron microscopy indicated good dispersion of nanoclay in the PCL matrix. Reinforcement of nanoclay in PCL enhanced mechanical properties without affecting thermal and degradation properties of PCL. Cytocompatibility of PCL/clay nanocomposites was studied using both osteoblasts and endothelial cells in vitro. Both composites (PCL/C30B and PCL/C93A) were cytotoxic with high toxicity observed for C30B even at low content of 1 wt %. The cytotoxicity was found to arise due to leachables from PCL/clay composites. Electrical conductivity measurements of aqueous media confirmed leaching of cationic surfactant from the PCL/clay composites PCL matrix. Both composites were found to be bactericidal but C30B was more effective than C93A. Taken together, it was observed that organically-modified nanoclay as fillers in PCL improves mechanical properties and imparts bactericidal properties but with increased risk of toxicity. These PCL/clay composites may be useful as stronger packaging material with antibacterial properties but are not suited as biomedical implants or for food packaging applications.

  20. Serum bactericidal assay for the evaluation of typhoid vaccine using a semi-automated colony-counting method.

    Science.gov (United States)

    Jang, Mi Seon; Sahastrabuddhe, Sushant; Yun, Cheol-Heui; Han, Seung Hyun; Yang, Jae Seung

    2016-08-01

    Typhoid fever, mainly caused by Salmonella enterica serovar Typhi (S. Typhi), is a life-threatening disease, mostly in developing countries. Enzyme-linked immunosorbent assay (ELISA) is widely used to quantify antibodies against S. Typhi in serum but does not provide information about functional antibody titers. Although the serum bactericidal assay (SBA) using an agar plate is often used to measure functional antibody titers against various bacterial pathogens in clinical specimens, it has rarely been used for typhoid vaccines because it is time-consuming and labor-intensive. In the present study, we established an improved SBA against S. Typhi using a semi-automated colony-counting system with a square agar plate harboring 24 samples. The semi-automated SBA efficiently measured bactericidal titers of sera from individuals immunized with S. Typhi Vi polysaccharide vaccines. The assay specifically responded to S. Typhi Ty2 but not to other irrelevant enteric bacteria including Vibrio cholerae and Shigella flexneri. Baby rabbit complement was more appropriate source for the SBA against S. Typhi than complements from adult rabbit, guinea pig, and human. We also examined the correlation between SBA and ELISA for measuring antibody responses against S. Typhi using pre- and post-vaccination sera from 18 human volunteers. The SBA titer showed a good correlation with anti-Vi IgG quantity in the serum as determined by Spearman correlation coefficient of 0.737 (P typhoid vaccines.

  1. Effect of diesel leakage in circulating cooling water system on preponderant bacteria diversity and bactericidal effect of biocides.

    Science.gov (United States)

    Zhong, Huiyun; Liu, Fang; Lu, Jinjin; Yang, Wei; Zhao, Chaocheng

    2015-01-01

    Petroleum products leakage results in adverse effect on the normal operation of a circulating cooling water system. However, relatively little research has been done to explore the effect of petroleum products leakage on circulating cooling water quality and biofilm preponderant bacteria diversity. Also, normal biocides application modes cannot fulfil the need for biofilm control. In this study, diesel oil was used as the experimental subject representing leaking petroleum products; the effect of diesel addition on biofilm preponderant bacteria diversity and the bactericidal effect of chlorine dioxide and tetradecyl dimethyl benzyl ammonium chloride (1427) was investigated. Bacterial community structures were examined by PCR-denaturing gradient gel electrophoresis and PCR cloning of 16S rDNA genes. Except for 100 mg/L diesel, increasing diesel concentration enhanced the biofilm detachment ratio compared with the control test. The microstructure of biofilm samples with 0, 300 and 900 mg/L diesel addition was observed. The species of preponderant bacteria in the biofilm sample with 300 mg/L diesel addition were more and the bacterial distribution was more uniform than those in the biofilm sample with 900 mg/L diesel addition. With ClO2 and 1427 addition, chemical oxygen demand increased, lipid phosphorus and bacterial count first decreased and then remained stable, and the bactericidal ratio first increased and then remained stable. Diesel addition variation has more obvious effect on ClO2 than 1427.

  2. MetQ of Neisseria gonorrhoeae Is a Surface-Expressed Antigen That Elicits Bactericidal and Functional Blocking Antibodies

    Science.gov (United States)

    Semchenko, Evgeny A.; Day, Christopher J.

    2016-01-01

    ABSTRACT Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection (STI) gonorrhea, is a growing public health threat for which a vaccine is urgently needed. We characterized the functional role of the gonococcal MetQ protein, which is the methionine binding component of an ABC transporter system, and assessed its potential as a candidate antigen for inclusion in a gonococcal vaccine. MetQ has been found to be highly conserved in all strains investigated to date, it is localized on the bacterial surface, and it binds l-methionine with a high affinity. MetQ is also involved in gonococcal adherence to cervical epithelial cells. Mutants lacking MetQ have impaired survival in human monocytes, macrophages, and serum. Furthermore, antibodies raised against MetQ are bactericidal and are able to block gonococcal adherence to epithelial cells. These data suggest that MetQ elicits both bactericidal and functional blocking antibodies and is a valid candidate antigen for additional investigation and possible inclusion in a vaccine for prevention of gonorrhea. PMID:27895130

  3. Influence of saliva-coating on the ultraviolet-light-induced photocatalytic bactericidal effects on modified titanium surfaces

    Science.gov (United States)

    Lee, Jeong-Eun; Park, So-Yoon; Chang, Young-Il; Lim, Young-Jun; Ahn, Sug-Joon

    2012-07-01

    The purpose of this study was to investigate the ultraviolet-light-induced photocatalytic bactericidal effects of titanium surfaces on Streptococcus sanguinis in the presence of saliva-coating. Three different titanium disks were prepared: machined (MA), heat-treated (HT), and anodized surfaces (AO). Each disk was incubated with whole saliva or phosphate-buffered saline for 2 h. Antibacterial tests were performed by incubating a S. sanguinis suspension with each disk for 90 or 180 min under ultraviolet (UV) illumination. The viable counts of bacteria were enumerated from the cell suspension and the UV-light-induced photocatalytic bactericidal effects were determined by the bacterial survival rate. Without saliva-coating, AO disks exhibited significantly decreased bacterial survival rates compared to MA disks. The bacterial survival rates of the HT disks were intermediate between MA and AO in the absence of saliva-coating. However, saliva-coating significantly increased bacterial survival rates in all surface types. There was no significant difference in bacterial survival rates among the three surface types after saliva-coating. This study suggests that Ti-based antibacterial implant materials using TiO2 photocatalyst may have a limitation for intraoral use.

  4. Transgenic zebrafish eggs containing bactericidal peptide is a novel food supplement enhancing resistance to pathogenic infection of fish.

    Science.gov (United States)

    Lin, Cheng-Yung; Yang, Ping-Hsi; Kao, Chia-Ling; Huang, Han-I; Tsai, Huai-Jen

    2010-03-01

    Zebrafish (Danio rerio) was used as a bioreactor to produce bovine lactoferricin (LFB), which has wide-ranging antimicrobial activity. We constructed an expression plasmid in which LFB was fused with green fluorescent protein (GFP) and driven by zebrafish beta-actin promoter. After microinjection, six transgenic founders were screened on the basis of GFP appearance. Among them, a stable ZBL-5 line was selected by the ubiquitous and strong expression of GFP. Using PCR and Western blot analysis, we confirmed that the recombinant LFB-GFP protein was produced by the F2 progeny derived from the ZBL-5 line. The bactericidal agar plate assay proved that the functional domain of LFB was released from the LFB-GFP fusion protein, resulting in strong bactericidal activity against Escherichia coli, Edwardsiella tarda and Aeromonas hydrophila. Furthermore, adult zebrafish were given one feeding of fifty 72-hpf transgenic embryos. The treated fish were then immersed in freshwater containing 1 x 10(5) CFU ml(-1)E. tarda for 7 days. The survival rate of the treated zebrafish was significantly higher than that of fish fed with fifty wild-type embryos (75 +/- 12.5% versus 4 +/- 7.2%). This line of evidence suggested that pathogen resistance can be enhanced by using transgenic embryos containing LFB-GFP as a food supplement for fish, while, at the same time, reducing the demand of chemical antibiotics.

  5. Anti-biofilm and bactericidal effects of magnolia bark-derived magnolol and honokiol on Streptococcus mutans.

    Science.gov (United States)

    Sakaue, Yuuki; Domon, Hisanori; Oda, Masataka; Takenaka, Shoji; Kubo, Miwa; Fukuyama, Yoshiyasu; Okiji, Takashi; Terao, Yutaka

    2016-01-01

    Dental caries affects people of all ages and is a worldwide health concern. Streptococcus mutans is a major cariogenic bacterium because of its ability to form biofilm and induce an acidic environment. In this study, the antibacterial activities of magnolol and honokiol, the main constituents of the bark of magnolia plants, toward planktonic cell and biofilm of S. mutans were examined and compared with those of chlorhexidine. The minimal inhibitory concentrations of magnolol, honokiol and chlorhexidine for S. mutans were 10, 10 and 0.25 µg/mL, respectively. In addition, each agent showed bactericidal activity against S. mutans planktonic cells and inhibited biofilm formation in a dose- and time-dependent manner. Magnolol (50 µg/mL) had greater bactericidal activity against S. mutans biofilm than honokiol (50 µg/mL) and chlorhexidine (500 µg/mL) at 5 min after exposure, while all showed scant activity against biofilm at 30 s. Furthermore; chlorhexidine (0.5-500 µg/mL) exhibited high cellular toxicity for the gingival epithelial cell line Ca9-22 at 1 hr, whereas magnolol (50 µg/mL) and honokiol (50 µg/mL) did not. Thus; it was found that magnolol has antimicrobial activities against planktonic and biofilm cells of S. mutans. Magnolol may be a candidate for prevention and management of dental caries.

  6. In vitro sensitivity of oral, gram-negative, facultative bacteria to the bactericidal activity of human neutrophil defensins.

    Science.gov (United States)

    Miyasaki, K T; Bodeau, A L; Ganz, T; Selsted, M E; Lehrer, R I

    1990-12-01

    Neutrophils play a major role in defending the periodontium against infection by oral, gram-negative, facultative bacteria, such as Actinobacillus actinomycetemcomitans, Eikenella corrodens, and Capnocytophaga spp. We examined the sensitivity of these bacteria to a mixture of low-molecular-weight peptides and highly purified individual defensin peptides (HNP-1, HNP-2, and HNP-3) isolated from human neutrophils. Whereas the Capnocytophaga spp. strains were killed significantly by the mixed human neutrophil peptides, the A. actinomycetemcomitans and E. corrodens strains were resistant. Killing was attributable to the defensins. The bactericidal activities of purified defensins HNP-1 and HNP-2 were equal, and both of these activities were greater than HNP-3 activity against strains of Capnocytophaga sputigena and Capnocytophaga gingivalis. The strain of Capnocytophaga ochracea was more sensitive to defensin-mediated bactericidal activity than either C. sputigena or C. gingivalis was. The three human defensins were equipotent in killing C. ochracea. C. ochracea was killed under aerobic and anaerobic conditions and over a broad pH range. Killing was most effective under hypotonic conditions but also occurred at physiologic salt concentrations. We concluded that Capnocytophaga spp. are sensitive to oxygen-independent killing by human defensins. Additional studies will be required to identify other components that may equip human neutrophils to kill A. actinomycetemcomitans, E. corrodens, and other oral gram-negative bacteria.

  7. Controlled assembly of silver nano-fluid in Heliotropium crispum extract: A potent anti-biofilm and bactericidal formulation

    Science.gov (United States)

    Khan, Faria; Hashmi, Muhammad Uzair; Khalid, Nauman; Hayat, Muhammad Qasim; Ikram, Aamer; Janjua, Hussnain A.

    2016-11-01

    The study describes the optimized method for silver nanoparticle (AgNPs) synthesis using Heliotropium crispum (HC) plant extract. Optimization of physicochemical parameters resulted in stable and rapidly assembled AgNPs. FTIR results suggest presence of plant phytochemicals that helped in the reduction, stabilization and capping of AgNPs. The assembled Ag nano-composites displayed the peak surface plasmon resonance (SPR) around 428 nm. The presence of uniquely assembled Ag-biomolecule composites, cap and stabilize nanoparticles in aqueous plant suspension. Spherical, uniform-shaped AgNPs with low poly-dispersion and average particle size of 42 nm and was determined through dynamic light scattering (DLS) and scanning election microscopy (SEM) which present robust interaction with microbes. The study also evaluates the antimicrobial and anti-biofilm properties of biologically synthesized AgNPs on clinical isolates of MRSA, Pseudomonas aeruginosa and Acinetobacter baumannii. Minimum inhibitory concentration (0.5 mg mL-1) of nanoparticles that presented bactericidal effect was made through inhibition assays on bacterial strains. The concentration which presented potent bactericidal response was then evaluated through growth inhibition in liquid medium for anti-biofilm studies at 2.0 mg mL-1. HC-Ag nanoparticles mediated anti-biofilm effects on Pseudomonas aeruginosa was revealed through SEM. Complete breakdown of biofilm's extracellular polymeric substances resulted after incubation with AgNPs. Peptidoglycan cell wall destruction was also revealed on planktonic bacterial images after 24 h of incubation.

  8. In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamruzzaman; S.M. Nayeemul Bari; Shah M. Faruque

    2013-01-01

    Objective: To investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens. Methods: Water and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). Results: Methanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9-22.6 mm, MIC:200-3 200 μg/mL, MBC: 200-6 400 μg/mL) against all the pathogenic enteric bacteria (Vibriocholerae , Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001). Conclusions: For the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

  9. Photocatalytic Bactericidal Efficiency of Ag Doped TiO2/Fe3O4 on Fish Pathogens under Visible Light

    Directory of Open Access Journals (Sweden)

    Ekkachai Kanchanatip

    2014-01-01

    Full Text Available This research evaluates photocatalytic bactericidal efficiencies of Ag-TiO2/Fe3O4 in visible light using target pollutants that include Aeromonas hydrophila, Edwardsiella tarda, and Photobacterium damselae subsp. piscicida. The investigation started with Ag-TiO2/Fe3O4 synthesis and calcination followed by a series of product tests that include the examination of crystallite phase, light absorption, element composition morphology, and magnetic properties. The results of the experiment indicate that Ag and Fe3O4 significantly enhanced the light absorption capacity of TiO2 in the entire visible light range. The Ag-TiO2/Fe3O4 prepared in this study displays significantly enhanced visible light absorption and narrowed band gap energy. The magnetic property of Ag-TiO2/Fe3O4 made it easy for retrieval using a permanent magnet bar. The photocatalytic activity of Ag-TiO2/Fe3O4 remains above 85% after three application cycles, which indicates high and favorable efficiency in bactericidal evaluation. The experiments have proved that the Ag-TiO2/Fe3O4 magnetic photocatalyst is a promising photocatalyst for antibacterial application under visible light.

  10. In Vitro Bactericidal Activity of 4- and 5-Chloro-2-hydroxy-N-[1-oxo-1-(phenylaminoalkan-2-yl]benzamides against MRSA

    Directory of Open Access Journals (Sweden)

    Iveta Zadrazilova

    2015-01-01

    Full Text Available A series of nine substituted 2-hydroxy-N-[1-oxo-1-(phenylaminoalkan-2-yl]benzamides was assessed as prospective bactericidal agents against three clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA and S. aureus ATCC 29213 as the reference and quality control strain. The minimum bactericidal concentration was determined by subculturing aliquots from MIC determination onto substance-free agar plates. The bactericidal kinetics of compounds 5-chloro-2-hydroxy-N-[(2S-3-methyl-1-oxo-1-{[4-(trifluoromethylphenyl]amino}butan-2-yl]benzamide (1f, N-{(2S-1-[(4-bromophenylamino]-3-methyl-1-oxobutan-2-yl}-4-chloro-2-hydroxybenzamide (1g, and 4-chloro-N-{(2S-1-[(3,4-dichlorophenylamino]-3-methyl-1-oxobutan-2-yl}-2-hydroxybenzamide (1h was established by time-kill assay with a final concentration of the compound equal to 1x, 2x, and 4x MIC; aliquots were removed at 0, 4, 6, 8, and 24 h time points. The most potent bactericidal agent was compound 1f exhibiting remarkable rapid concentration-dependent bactericidal effect even at 2x MIC at 4, 6, and 8 h (with a reduction in bacterial count ranging from 3.08 to 3.75 log10 CFU/mL and at 4x MIC at 4, 6, 8, and 24 h (5.30 log10 CFU/mL reduction in bacterial count after incubation against MRSA 63718. Reliable bactericidal effect against other strains was maintained at 4x MIC at 24 h.

  11. Comparison of bactericidal efficiency of 7.5 MeV X-rays, gamma-rays, and 10 MeV e-beams

    Science.gov (United States)

    Song, Beom-Seok; Lee, Yunjong; Moon, Byeong-Geum; Go, Seon-Min; Park, Jong-Heum; Kim, Jae-Kyung; Jung, Koo; Kim, Dong-Ho; Ryu, Sang-Ryeol

    2016-08-01

    This study was performed to verify the feasibility of 7.5 MeV X-rays for food pasteurization through a comparison of the bactericidal efficiency with those of other sources for selected bacterial pathogens. No significant differences were observed between the overall bactericidal efficiency for beef-inoculated pathogens based on the uncertainty of the absorbed dose and variations in bacterial counts. This result supported that all three irradiation sources were effective for inactivation of food-borne bacteria and that 7.5 MeV X-rays may be used for food pasteurization.

  12. Interaction Of ZnO Nanoparticles With Food Borne Pathogens Escherichia coli DH5α and Staphylococcus aureus 5021 & Their Bactericidal Efficacy

    Science.gov (United States)

    Kaur, Pawan; Thakur, Rajesh; Kumar, Sandeep; Dilbaghi, Neeraj

    2011-12-01

    Bactericidal activity of ZnO nanoparticles (np) against the food borne pathogens E. coli DH5α (Gram-ve) and & S. aureus 5021 (Gram+ve), and the mechanism of their interaction with target microbes was studied. Bactericidal activity of ZnO np was attributed to disruption of cell membrane causing cytoplasmic leakage, which was measured by quantifying the leakage of nucleic acids, proteins and K+ ions from the cells using UV-VIS Spectrophotometry and Atomic Absorption Spectrophotometry, respectively. Cell membrane disruption was observed through TEM. It is proposed that both the abrasiveness and the surface oxygen species of ZnO np are responsible for their biocidal properties.

  13. Effect of ZnO morphology on affecting bactericidal property of ultra high molecular weight polyethylene biocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Rajeev Kumar [Biomaterials Processing and Characterization Laboratory, Indian Institute of Technology Kanpur, Kanpur -208016 (India); Agarwal, Meenakshi [Amity Institute of Nanotechnology, Amity University, Noida, Uttar Pradesh - 201303 (India); Balani, Kantesh, E-mail: kbalani@iitk.ac.in [Biomaterials Processing and Characterization Laboratory, Indian Institute of Technology Kanpur, Kanpur -208016 (India)

    2016-05-01

    Bacterial infection of implants can be controlled by selective trapping of bacteria, followed with consequent killing by targeted antibacterial agents. Herein, the role of various ZnO morphologies, viz. micro-rods (R), nanoparticles (NP), and micro-disks (D) on antibacterial efficacy of ZnO via release of Zn{sup 2+} and H{sub 2}O{sub 2} is assessed, both as isolated powders and via incorporating them in cytocompatible ultra high molecular weight polyethylene (UHMWPE). Though ZnO is antibacterial, interestingly, all ZnO morphologies elicited a supportive growth of gram-negative bacteria (Escherichia coli) in culture medium (until 28–35 μg/ml). But, all ZnO morphologies did elicit bactericidal effect on gram positive bacteria (Staphylococcus aureus or Staphylococcus epidermidis) both in culture medium (for 0–2.5 μg/ml) or when incorporated (5–20 wt.%) into UHMWPE. The bactericidal mechanisms were quantified for various ZnO morphologies via: (i) H{sub 2}O{sub 2} production, (ii) Zn{sup 2+} release, and (iii) the presence of surface oxygen vacancies. On one hand, where only ZnO(NP) elicited release of H{sub 2}O{sub 2} in the absence of light, maximum Zn{sup 2+} release was elicited by ZnO(D). Interestingly, when ZnO is incorporated as reinforcement (5–20 wt.%), its antibacterial action against E. coli was vividly observed due to selective proliferation of bacteria only on friendly UHMWPE matrix. Hence, luring bacteria on affable UHMWPE surface can be complemented with their targeted killing by ZnO present in composite. - Highlights: • The role of ZnO morphology in affecting bactericidal mechanisms • Quantification of Zn{sup 2+} release, H{sub 2}O{sub 2} production and surface oxygen vacancy defects • Inherent resistance by gram negative bacteria at lower ZnO concentrations • Containment of bacteria on polymeric surface and consequent targeted killing by ZnO.

  14. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with short-term, low-energy UV irradiation

    Science.gov (United States)

    Narita, K.; Ono, A.; Wada, K.; Tanaka, T.; Kumagai, G.; Yamauchi, R.; Nakane, A.; Ishibashi, Y.

    2017-01-01

    Objectives The surface of pure titanium (Ti) shows decreased histocompatibility over time; this phenomenon is known as biological ageing. UV irradiation enables the reversal of biological ageing through photofunctionalisation, a physicochemical alteration of the titanium surface. Ti implants are sterilised by UV irradiation in dental surgery. However, orthopaedic biomaterials are usually composed of the alloy Ti6Al4V, for which the antibacterial effects of UV irradiation are unconfirmed. Here we evaluated the bactericidal and antimicrobial effects of treating Ti and Ti6Al4V with UV irradiation of a lower and briefer dose than previously reported, for applications in implant surgery. Materials and Methods Ti and Ti6Al4V disks were prepared. To evaluate the bactericidal effect of UV irradiation, Staphylococcus aureus 834 suspension was seeded onto the disks, which were then exposed to UV light for 15 minutes at a dose of 9 J/cm2. To evaluate the antimicrobial activity of UV irradiation, bacterial suspensions were seeded onto the disks 0, 0.5, one, six, 24 and 48 hours, and three and seven days after UV irradiation as described above. In both experiments, the bacteria were then harvested, cultured, and the number of colonies were counted. Results No colonies were observed when UV irradiation was performed after the bacteria were added to the disks. When the bacteria were seeded after UV irradiation, the amount of surviving bacteria on the Ti and Ti6Al4V disks decreased at 0 hours and then gradually increased. However, the antimicrobial activity was maintained for seven days after UV irradiation. Conclusion Antimicrobial activity was induced for seven days after UV irradiation on both types of disk. Irradiated Ti6Al4V and Ti had similar antimicrobial properties. Cite this article: T. Itabashi, K. Narita, A. Ono, K. Wada, T. Tanaka, G. Kumagai, R. Yamauchi, A. Nakane, Y. Ishibashi. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with

  15. PREPARATION OF TITANIA SOL-GEL COATINGS CONTAINING SILVER IN VARIOUS FORMS AND MEASURING OF THEIR BACTERICIDAL EFFECTS AGAINST E. COLI

    Directory of Open Access Journals (Sweden)

    Diana Horkavcova

    2015-09-01

    Full Text Available The work describes titania coatings containing various forms of silver applied on a titanium substrate by a dip-coating sol-gel technique. Silver was added into the basic titania sol in form of colloid particles of Ag, crystals of AgNO3, particles of AgI, particles of Ag3PO4 and Ag3PO4 developed in situ (in the sol by reaction of AgNO3 with added calcium phosphate (brushite or monetite. Mechanically and chemically treated titanium substrates were dipped at a constant rate into individual types of sols. Subsequently, they were slowly fired. The fired coatings contained microcracks. All over the surface there were evenly distributed spherical nanoparticles of silver (Ag, AgNO3 or microcrystals of AgI and Ag3PO4. The prepared coatings were tested under static conditions for their bactericidal effects against gram-negative bacteria Escherichia coli (E. coli. The coated substrates were immersed into a suspension of E. coli in physiological solution for 24 and 4 hours. The basic titania coatings with no silver demonstrated no bactericidal properties. Very good bactericidal effect against E. coli in both types of bactericidal test showed the titania coatings with AgNO3, Ag3PO4 crystals and Ag3PO4 developed in situ.

  16. Validity of the four European test strains of prEN 12054 for the determination of comprehensive bactericidal activity of an alcohol-based hand rub.

    Science.gov (United States)

    Kampf, G; Hollingsworth, A

    2003-11-01

    A comprehensive bactericidal activity of an alcohol-based hand rub is essential for prevention of cross-transmission by the hands of healthcare workers. In Europe, however, only four test organisms are used to determine bactericidal activity according to prEN 12054. The susceptibility of the various bacterial species against the commonly used alcohols is thought to be similar, but so far this has never been studied. We therefore evaluated the bactericidal activity of an alcohol-based hand rub (Sterillium) within 30 s in compliance with prEN 12054 and in a time kill test against 13 Gram-positive, 18 Gram-negative bacteria and 14 antibiotic-resistant bacterial pathogens. Each strain was evaluated in quadruplicate. Counts of the four test bacteria of prEN 12054 were reduced by factors exceeding 10(5) within 30 s. In the time kill test, all 13 Gram-positive and all 18 Gram-negative bacteria were reduced more than 10(5)-fold within 30 s, not only against the ATCC test strains but also against corresponding clinical isolates. Comparable reductions were also observed against all 14 emerging bacterial pathogens. The four European test bacteria were found to be sufficient to determine a comprehensive bactericidal activity of a propanol-based hand rub.

  17. In vitro analysis on bactericidal screening and antioxidant potentiality of leaf and root extracts of Thottea siliquosa (Lam. Ding Hou. An ethnobotanical plant

    Directory of Open Access Journals (Sweden)

    Saiba Abdul Wahab Nusaiba

    2013-11-01

    Conclusion: The present study provides evidence that ethyl acetate and methanol extract of leaf and root of T. siliquosa are potential source of natural antioxidants and bactericidal nature. It is essential that research should continue to isolate and purify the bio active components of this natural plant and use in drug discovery and development.

  18. Understanding of gas phase deposition of reactive magnetron sputtered TiO2 thin films and its correlation with bactericidal efficiency

    Science.gov (United States)

    Panda, A. B.; Mahapatra, S. K.; Barhai, P. K.; Das, A. K.; Banerjee, I.

    2012-10-01

    Nanostructured TiO2 thin films were deposited using RF reactive magnetron sputtering at different O2 flow rates (20, 30, 50 and 60 sccm) and constant RF power of 200 W. In situ investigation of the nucleation and growth of the films was made by Optical Emission Spectroscopy (OES). The nano amorphous nature as revealed from X-ray diffraction (XRD) of the as deposited films and abundance of the Ti3+ surface oxidation states and surface hydroxyl group (OH-) in the films deposited at 50 sccm as determined from X-ray photo electron spectroscopy (XPS) was explained on the basis of emission spectra studies. The increase in band gap and decrease in particle size with O2 flow rate was observed from transmission spectra of UV-vis spectroscopy. Photoinduced hydrophilicity has been studied using Optical Contact Angle (OCA) measurement. The post irradiated films showed improved hydrophilicity. The bactericidal efficiency of these films was investigated taking Escherichia coli as model bacteria. The films deposited at 50 sccm shows better bactericidal activity as revealed from the optical density (OD) measurement. The qualitative analysis of the bactericidal efficiency was depicted from Scanning Electron Microscope images. A correlation between bactericidal efficiency and the deposited film has been established and explained on the basis of nucleation growth, band gap and hydrophilicity of the films.

  19. Antimycobacterial agents differ with respect to their bacteriostatic versus bactericidal activities in relation to time of exposure, mycobacterial growth phase, and their use in combination.

    NARCIS (Netherlands)

    I.A.J.M. Bakker-Woudenberg (Irma); W. van Vianen (Wim); D. van Soolingen (Dick); H.A. Verbrugh (Henri); M.A. Agtmael (Michiel)

    2005-01-01

    textabstractA number of antimycobacterial agents were evaluated with respect to their bacteriostatic activity (growth inhibition) versus the bactericidal activity against a clinical isolate of Mycobacterium avium (Mycobacterium avium complex [MAC] strain 101) in relation to the time of exposure and

  20. Polymyxin Combination Therapy and the Use of Serum Bactericidal Titers in the Management of KPC-Producing Klebsiella pneumoniae Infections: A Report of 3 Cases

    Directory of Open Access Journals (Sweden)

    Eric Gomez

    2011-01-01

    Full Text Available Management of patients with KPC-harboring Enterobacteriaceae has become a significant and challenging scenario. We report three cases of KPC-producing Klebsiella pneumoniae bacteremia that were successfully treated using combination therapy with polymyxin B and other antimicrobials. Serum bactericidal titers were determined and provided additional clinical guidance in the management of such patients.

  1. Bactericidal activities of health-promoting,food-derived powders against the foodborne pathogens Escherichia coli,listeria monocytogenes, salmonella enterica,and staphylococcus aureus

    Science.gov (United States)

    We evaluated the relative bactericidal activities of 10 presumed health-promoting food-based powders (nutraceuticals) and for comparison, several selected known components of such powders against the following foodborne pathogens: Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes...

  2. Neutrophil bactericidal activity against Staphylococcus aureus adherent on biological surfaces. Surface-bound extracellular matrix proteins activate intracellular killing by oxygen-dependent and -independent mechanisms.

    Science.gov (United States)

    Hermann, M; Jaconi, M E; Dahlgren, C; Waldvogel, F A; Stendahl, O; Lew, D P

    1990-09-01

    The activation patterns of surface adherent neutrophils are modulated via interaction of extracellular matrix proteins with neutrophil integrins. To evaluate neutrophil bactericidal activity, Staphylococcus aureus adherent to biological surfaces were incubated with neutrophils and serum, and the survival of surface bacteria was determined. When compared to albumin-coated surfaces, the bactericidal activity of neutrophils adherent to purified human extracellular matrix was markedly enhanced (mean survival: 34.2% +/- 9.0% of albumin, P less than 0.0001) despite similar efficient ingestion of extracellular bacteria. Enhancement of killing was observed when surfaces were coated with purified constituents of extracellular matrix, i.e., fibronectin, fibrinogen, laminin, vitronectin, or type IV collagen. In addition to matrix proteins, the tetrapeptide RGDS (the sequence recognized by integrins) crosslinked to surface bound albumin was also active (survival: 74.5% +/- 5.5% of albumin, P less than 0.02), and fibronectin-increased killing was inhibited by soluble RGDS. Chemiluminescence measurements and experiments with CGD neutrophils revealed that both oxygen-dependent and -independent bactericidal mechanisms are involved. In conclusion, matrix proteins enhance intracellular bactericidal activity of adherent neutrophils, presumably by integrin recognition of RGDS-containing ligands. These results indicate a role for extracellular matrix proteins in the enhancement of the host defense against pyogenic infections.

  3. Nanostructured poly (lactic acid) electrospun fiber with high loadings of TiO2 nanoparticles: Insights into bactericidal activity and cell viability.

    Science.gov (United States)

    Toniatto, T V; Rodrigues, B V M; Marsi, T C O; Ricci, R; Marciano, F R; Webster, T J; Lobo, A O

    2017-02-01

    Researchers have been looking for modifying surfaces of polymeric biomaterials approved by FDA to obtain nanofeatures and bactericidal properties. If modified, it would be very interesting because the antibiotic administration could be reduced and, therefore, the bacterial resistance. Here, we report the electrospinning of poly (lactic acid) (PLA) with high loadings of titanium dioxide nanoparticles (TiO2, 1-5wt%) and their bactericidal properties. TiO2 nanoparticles have been recognized for a long time for their antibacterial, low cost and self-cleaning properties. However, their ability to reduce bacteria functions when used in polymers has not been well studied to date. In this context, we aimed here to generate nanostructured PLA electrospun fiber-TiO2 nanoparticle composites for further evaluation of their bactericidal activity and cell viability. TEM and SEM micrographs revealed the successful electrospinning of PLA/TiO2 and the generation of polymer-TiO2 nanostructures. When increasing the TiO2 concentration, we observed a proportional increase in the nanoparticle density along the fiber and surface. The nanostructured PLA/TiO2 nanofibers showed no mammalian cell toxicity and, most importantly, possessed bactericidal activity with higher TiO2 loads. Such results suggest that the present PLA electrospun fiber-TiO2 nanoparticle composites should be further studied for a wide range of biomedical applications.

  4. Antimicrobial activity of peptides derived from olive flounder lipopolysaccharide binding protein/bactericidal permeability-increasing protein (LBP/BPI).

    Science.gov (United States)

    Nam, Bo-Hye; Moon, Ji-Young; Park, Eun-Hee; Kim, Young-Ok; Kim, Dong-Gyun; Kong, Hee Jeong; Kim, Woo-Jin; Jee, Young Ju; An, Cheul Min; Park, Nam Gyu; Seo, Jung-Kil

    2014-10-17

    We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.

  5. Correlation between bactericidal activity of fosfomycin trometamol in an in vitro model of the urinary bladder and susceptibility testing.

    Science.gov (United States)

    Pinasi, C; Albini, E; Marca, G

    1987-01-01

    The present study was undertaken to define an interpretative guideline for disk diffusion susceptibility testing with fosfomycin trometamol, a new antimicrobial agent which has been developed for the treatment of urinary tract infections. Two potencies of fosfomycin disk were used: 50 and 200 micrograms, prepared in the presence and absence of glucose-6-phosphate. To verify the reliability of the results obtained in susceptibility testing, we have also evaluated the bactericidal activity of fosfomycin trometamol versus sensitive and resistant strains in an 'in vitro' model simulating the hydrokinetic aspects involved in the treatment of bacterial cystitis. The data obtained evidenced the role of glucose-6-phosphate in antimicrobial susceptibility tests as well as the importance of the urinary antibiotic concentrations to define sensitive and resistant bacteria. On the basis of our results, we recommend that a 200-microgram disk of fosfomycin containing 50 micrograms of glucose-6-phosphate should be used in antimicrobial susceptibility testing with fosfomycin trometamol.

  6. N-halamine-decorated polystyrene nanoparticles based on 5-allylbarbituric acid: from controllable fabrication to bactericidal evaluation.

    Science.gov (United States)

    Dong, Alideertu; Huang, Zhen; Lan, Shi; Wang, Qin; Bao, Sarina; Siriguleng; Zhang, Yanling; Gao, Ge; Liu, Fengqi; Harnoode, Chokto

    2014-01-01

    N-halamine-based antibacterial polystyrene nanoparticles with different particle size ranged from 91.5 nm to 562.5 nm were facilely fabricated by surfactant-free emulsion polymerization with 5-allylbarbituric acid served as N-halamine precursor. Effect of experimental parameters such as monomer concentration, initiator concentration, and ionic strength on particle size was investigated systematically. N-halamine-based antibacterial polystyrene nanoparticles showed enhanced antibacterial activity against both Gram-positive species Staphylococcus aureus and Gram-negative species Pseudomonas aeruginosa compared with bulk powder N-halamine. Biocidal activity of N-halamine-based antibacterial polystyrene nanoparticles can be tailored effectively by tuning particle size. Stability and bactericidal activity of N-halamine-based antibacterial polystyrene nanoparticles was detected as a function of extending period.

  7. Bactericidal and Photocatalytic Activity of Fe3+- TiO2 Thin Films Prepared by the Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    WANG Xun; GONG Wenqi

    2008-01-01

    Pure TiO2 thin films and iron doped TiO2 thin films on glass substrate were prepared by sol-gel method, and characterized by X-ray diffractometer (XRD), thermo-gravimetric analysis (TG-DSC), high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM) and UV-Vis spectroscopy, respectively. The experimental results show that the pure TiO2 thin films and iron doped TiO2 thinfilms can destroy most of the eseheriehia coli and bacillus subtillis under the irradiation of 365 nm UV-light.However, the iron doped TiO2 thin film is a better photocatalyst than pure TiO2 thin film. The ultrastructural studies provide direct evidences for understanding the bactericidal mechanism of the TiO2 photocatalyst.

  8. Histological response of soda-lime glass-ceramic bactericidal rods implanted in the jaws of beagle dogs.

    Science.gov (United States)

    Moya, José S; Martínez, Arturo; López-Píriz, Roberto; Guitián, Francisco; Díaz, Luis A; Esteban-Tejeda, Leticia; Cabal, Belén; Sket, Federico; Fernández-García, Elisa; Tomsia, Antoni P; Torrecillas, Ramón

    2016-08-12

    Bacterial and fungal infections remain a major clinical challenge. Implant infections very often require complicated revision procedures that are troublesome to patients and costly to the healthcare system. Innovative approaches to tackle infections are urgently needed. We investigated the histological response of novel free P2O5 glass-ceramic rods implanted in the jaws of beagle dogs. Due to the particular percolated morphology of this glass-ceramic, the dissolution of the rods in the animal body environment and the immature bone formation during the fourth months of implantation maintained the integrity of the glass-ceramic rod. No clinical signs of inflammation took place in any of the beagle dogs during the four months of implantation. This new glass-ceramic biomaterial with inherent bactericidal and fungicidal properties can be considered as an appealing candidate for bone tissue engineering.

  9. Preparation of AgBr@SiO{sub 2} core@shell hybrid nanoparticles and their bactericidal activity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuanyuan [Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004 (China); Yang, Lisu [Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004 (China); Henna Sports School, Zhengzhou 450045 (China); Zhao, Yanbao, E-mail: yanbaozhao@126.com [Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004 (China); Li, Binjie; Sun, Lei; Luo, Huajuan [Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004 (China)

    2013-04-01

    AgBr@SiO{sub 2} core@shell hybrid nanoparticles (NPs) were successfully prepared by sol-gel method. Their morphology and structure were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The hybrid NPs are predominantly spherical in shape, with an average diameter of 180–200 nm, and each NP contains one inorganic core. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the hybrid NPs were examined against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli), respectively. Results indicated that the AgBr@SiO{sub 2} NPs had excellent antibacterial activity. - Highlights: ► Presents a novel antibacterial agent “AgBr@ SiO{sub 2} NPs”. ► AgBr@SiO{sub 2} hybrid NPs could provide long-term antimicrobial effect. ► AgBr@SiO{sub 2} hybrid NPs have excellent antibacterial activity.

  10. Surotomycin demonstrates low in vitro frequency of resistance and rapid bactericidal activity in Clostridium difficile, Enterococcus faecalis, and Enterococcus faecium.

    Science.gov (United States)

    Mascio, Carmela T M; Chesnel, Laurent; Thorne, Grace; Silverman, Jared A

    2014-07-01

    Surotomycin (CB-183,315) is an orally administered, minimally absorbed, selective bactericidal cyclic lipopeptide in phase 3 development for the treatment of Clostridium difficile-associated diarrhea. The aim of this study was to evaluate the emergence of resistance in C. difficile (ATCC 700057 and three recent clinical isolates from the restriction endonuclease analysis groups BI, BK, and K), vancomycin-susceptible (VS) Enterococcus faecalis (ATCC 49452), vancomycin-resistant (VR) E. faecalis (ATCC 700802), VS Enterococcus faecium (ATCC 6569), and VR E. faecium (ATCC 51559) under anaerobic conditions. The rate of spontaneous resistance was below the limit of detection (Enterococcus (VSE), and VR Enterococcus (VRE), except for C. difficile BK (2.6-log-unit reductions for both). These results suggest that emergence of resistance to surotomycin against C. difficile, E. faecalis, and E. faecium is likely to be rare.

  11. Efecto bactericida del láser de diodo en periodoncia Bactericidal effects of diode laser in periodontology

    Directory of Open Access Journals (Sweden)

    G. Caccianiga

    2008-04-01

    associated use of laser irradiation and hydrogen peroxide with the goal of reducing the bacterial charge of stocks commonly present in the active periodontal pockets and resistant to the bactericide action of laser irradiation alone such as Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micron. The laboratory method used foresees the following protocol: each bacterial suspension has been exposed to hydrogen peroxide at 3% concentrations and it has been irradiated with laser for 10, 15 or 20 seconds, using sterile 1.5 ml Eppendorf tubes. The results confirm the higher bactericide effectiveness of the combined action of hydrogen peroxide and laser. The microbiological cultivations carried out reveal how, in spite of the bactericide effect, the laser has an insufficient action on bacterial stocks tested if it isn’t associated with hydrogen peroxide. Particularly in the case of the Prevotella intermedia or the Fusobacterium nucleatum the use of just hydrogen peroxide at 3% has offered better results than the laser irradiation alone while the association of both treatments has always offered optimal results. In the case of the Peptostreptococcus micron the use of hydrogen peroxide and laser separately has offered an insufficient reduction of the bacterial count while the association of treatments has increased their bactericide action.

  12. Antimicrobial Activity of Peptides Derived from Olive Flounder Lipopolysaccharide Binding Protein/Bactericidal Permeability-Increasing Protein (LBP/BPI

    Directory of Open Access Journals (Sweden)

    Bo-Hye Nam

    2014-10-01

    Full Text Available We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.

  13. Effect of ZnO morphology on affecting bactericidal property of ultra high molecular weight polyethylene biocomposite.

    Science.gov (United States)

    Sharma, Rajeev Kumar; Agarwal, Meenakshi; Balani, Kantesh

    2016-05-01

    Bacterial infection of implants can be controlled by selective trapping of bacteria, followed with consequent killing by targeted antibacterial agents. Herein, the role of various ZnO morphologies, viz. micro-rods (R), nanoparticles (NP), and micro-disks (D) on antibacterial efficacy of ZnO via release of Zn(2+) and H2O2 is assessed, both as isolated powders and via incorporating them in cytocompatible ultra high molecular weight polyethylene (UHMWPE). Though ZnO is antibacterial, interestingly, all ZnO morphologies elicited a supportive growth of gram-negative bacteria (Escherichia coli) in culture medium (until 28-35 μg/ml). But, all ZnO morphologies did elicit bactericidal effect on gram positive bacteria (Staphylococcus aureus or Staphylococcus epidermidis) both in culture medium (for 0-2.5 μg/ml) or when incorporated (5-20 wt.%) into UHMWPE. The bactericidal mechanisms were quantified for various ZnO morphologies via: (i) H2O2 production, (ii) Zn(2+) release, and (iii) the presence of surface oxygen vacancies. On one hand, where only ZnO(NP) elicited release of H2O2 in the absence of light, maximum Zn(2+) release was elicited by ZnO(D). Interestingly, when ZnO is incorporated as reinforcement (5-20 wt.%), its antibacterial action against E. coli was vividly observed due to selective proliferation of bacteria only on friendly UHMWPE matrix. Hence, luring bacteria on affable UHMWPE surface can be complemented with their targeted killing by ZnO present in composite.

  14. Enhanced Photothermal Bactericidal Activity of the Reduced Graphene Oxide Modified by Cationic Water-Soluble Conjugated Polymer.

    Science.gov (United States)

    Xiao, Linhong; Sun, Jinhua; Liu, Libing; Hu, Rong; Lu, Huan; Cheng, Chungui; Huang, Yong; Wang, Shu; Geng, Jianxin

    2017-02-15

    Surface modification of graphene is extremely important for applications. Here, we report a grafting-through method for grafting water-soluble polythiophenes onto reduced graphene oxide (RGO) sheets. As a result of tailoring of the side chains of the polythiophenes, the modified RGO sheets, that is, RGO-g-P3TOPA and RGO-g-P3TOPS, are positively and negatively charged, respectively. The grafted water-soluble polythiophenes provide the modified RGO sheets with good dispersibility in water and high photothermal conversion efficiencies (ca. 88%). Notably, the positively charged RGO-g-P3TOPA exhibits unprecedentedly excellent photothermal bactericidal activity, because the electrostatic attractions between RGO-g-P3TOPA and Escherichia coli (E. coli) bind them together, facilitating direct heat conduction through their interfaces: the minimum concentration of RGO-g-P3TOPA that kills 100% of E. coli is 2.5 μg mL(-1), which is only 1/16th of that required for RGO-g-P3TOPS to exhibit a similar bactericidal activity. The direct heat conduction mechanism is supported by zeta-potential measurements and photothermal heating tests, in which the achieved temperature of the RGO-g-P3TOPA suspension (2.5 μg mL(-1), 32 °C) that kills 100% of E. coli is found to be much lower than the thermoablation threshold of bacteria. Therefore, this research demonstrates a novel and superior method that combines photothermal heating effect and electrostatic attractions to efficiently kill bacteria.

  15. Bactericidal Effect of Lauric Acid-Loaded PCL-PEG-PCL Nano-Sized Micelles on Skin Commensal Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Thi-Quynh-Mai Tran

    2016-08-01

    Full Text Available Acne is the over growth of the commensal bacteria Propionibacterium acnes (P. acnes on human skin. Lauric acid (LA has been investigated as an effective candidate to suppress the activity of P. acnes. Although LA is nearly insoluble in water, dimethyl sulfoxide (DMSO has been reported to effectively solubilize LA. However, the toxicity of DMSO can limit the use of LA on the skin. In this study, LA-loaded poly(ɛ-caprolactone-poly(ethylene glycol-poly(ɛ-caprolactone micelles (PCL-PEG-PCL were developed to improve the bactericidal effect of free LA on P. acnes. The block copolymers mPEG-PCL and PCL-PEG-PCL with different molecular weights were synthesized and characterized using 1H Nuclear Magnetic Resonance spectroscopy (1H NMR, Fourier-transform infrared spectroscopy (FT-IR, Gel Permeation Chromatography (GPC, and Differential Scanning Calorimetry (DSC. In the presence of LA, mPEG-PCL diblock copolymers did not self-assemble into nano-sized micelles. On the contrary, the average particle sizes of the PCL-PEG-PCL micelles ranged from 50–198 nm for blank micelles and 27–89 nm for LA-loaded micelles. The drug loading content increased as the molecular weight of PCL-PEG-PCL polymer increased. Additionally, the minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC of free LA were 20 and 80 μg/mL, respectively. The MICs and MBCs of the micelles decreased to 10 and 40 μg/mL, respectively. This study demonstrated that the LA-loaded micelles are a potential treatment for acne.

  16. Comparative study of bactericidal activities, postantibiotic effects, and effects of bacterial virulence of penicillin G and six macrolides against Streptococcus pneumoniae.

    Science.gov (United States)

    Fuursted, K; Knudsen, J D; Petersen, M B; Poulsen, R L; Rehm, D

    1997-04-01

    In this report, we present MIC, bactericidal activity, postantibiotic effect (PAE), and in vivo infectivity data for postantibiotic-phase pneumococci. We compared and evaluated penicillin G and six macrolides, erythromycin, azithromycin, clarithromycin, dirithromycin, roxithromycin, and spiramycin, against 10 strains of pneumococci with various levels of susceptibility to penicillin. All of the agents, except azithromycin, exhibited a bactericidal effect (a > or = 3 log10 decrease in the number of CFU per milliliter) after 4 h of exposure to a concentration equal to 10 times the MIC, displaying the following hierarchy: spiramycin = penicillin G = erythromycin = dirithromycin = clarithromycin = roxithromycin > azithromycin. The bactericidal rate of penicillin G was significantly lower for resistant strains (MIC, > or = 2 microg/ml), while bactericidal rates of macrolides were unaffected by penicillin susceptibility. A PAE was induced in all of the strains by all of the antibiotics after exposure for 1 h to a concentration equivalent to 10 times the MIC. The mean duration of PAEs varied between 2.3 and 3.9 h, showing the following hierarchy: spiramycin = dirithromycin = clarithromycin = erythromycin = roxithromycin > azithromycin > penicillin G. Virulence studies were performed with immunocompetent mice by intraperitoneal inoculation of virulent, penicillin-susceptible serotype 3 pneumococci which had been pre-exposed to penicillin G or a macrolide for 1 h. A significant decrease in the virulence of postantibiotic-phase pneumococci was induced only by erythromycin, azithromycin, dirithromycin, and spiramycin, displaying 5.9-, 7.1-, 4.2-, and 3.6-fold increases in the 50% lethal dose (LD50) compared to a control suspension, respectively. No significant correlation could be demonstrated between the LD50 and the MIC, bactericidal activity, or PAE duration. These results suggest that antimicrobial interaction with host defenses in terms of virulence might be a

  17. A STUDY OF THE BACTERICIDAL PROPERTY OF AQUEOUS EXTRACT OF MEDICINAL PLANTS-ACACIA CATECHU AND FISCUS HISPIDA USED IN THE TRADITIONAL SYSTEM OF MEDICINE IN MANIPUR

    Directory of Open Access Journals (Sweden)

    Lokhendro Singh

    2014-07-01

    Full Text Available OBJECTIVE: To find out the bactericidal effect of extract of the Acacia catechu and Ficus hispida which are commonly used by the local quacks for the treatment of diarrhea and dysentery in the villages of the state of Manipur where the medical facilities are not available. METHODS: The plant barks are collected from different parts of Manipur during the period of March 2006 to February 2007, dried at room temperature; make powder in the grinder and soxhlated at low temperature to get the yield (extract. In case of Acacia catechu dried power form is available in the market. The powder is soxhlated to get the yield. These extracts are tested for the bactericidal effect in serial dilutions against the known strain of Staphylococcus aureus (ATCC 25923 and Escherichia coli (ATCC 25922 and incubated at 370C overnight. After overnight incubation, the tubes are checked for the growth of the organisms and from the tubes sub cultures are made serially corresponding to the dilutions on to the Blood agar, Mac Conkey and Nutrient agar media, incubated at 370C overnight. After overnight incubation, the dilution where the growth of the organisms does not occurred, are noted and tabulated. RESULT: The aqueous extract of Acacia catechu shows bactericidal effect up to the dilution of 1:8 whereas the aqueous extract of Ficus hispida shows no bactericidal effect even at higher concentration. CONCLUSION: These plants extract have been using for the treatment of ailments in the villages of the state of Manipur by the local quacks since time immemorial. In this study it has seen that Acacia catechu has the medicinal properties whereas Ficus hispida has no bactericidal property though the plant has other medicinal properties. It is therefore, necessary to do further studies to identify the ingredients present in this two plants for safe use and large scale production in the state.

  18. Urinary excretion and bactericidal activities of gemifloxacin and ofloxacin after a single oral dose in healthy volunteers.

    Science.gov (United States)

    Naber, C K; Hammer, M; Kinzig-Schippers, M; Sauber, C; Sörgel, F; Bygate, E A; Fairless, A J; Machka, K; Naber, K G

    2001-12-01

    In a randomized crossover study, 16 volunteers (8 men, 8 women) received single oral doses of 320 mg of gemifloxacin and 400 mg of ofloxacin on two separate occasions in the fasting state to assess the urinary excretion and urinary bactericidal titers (UBTs) at intervals for up to 144 h. Ofloxacin showed higher concentrations in urine compared with those of gemifloxacin. The median (range) cumulative excretion of gemifloxacin was 29.7% (8.4 to 48.7%) of the parent drug administered, and median (range) cumulative excretion of ofloxacin was 84.3% (46.5 to 95.2%) of the parent drug administered. The UBTs, i.e., the highest twofold dilutions (with antibiotic-free urine as the diluent) of urine that were still bactericidal, were determined for a reference strain and nine uropathogens for which the MICs of gemifloxacin and ofloxacin were as follows: Escherichia coli ATCC 25922, 0.016 and 0.06 microg/ml, respectively; Klebsiella pneumoniae, 0.03 and 0.06 microg/ml, respectively; Proteus mirabilis, 0.125 and 0.125 microg/ml, respectively; Escherichia coli, 0.06 and 0.5 microg/ml, respectively; Pseudomonas aeruginosa, 1 and 4 microg/ml, respectively; Staphylococcus aureus, 0.008 and 0.25 microg/ml, respectively; Enterococcus faecalis, 0.06 and 2 microg/ml, respectively; Staphylococcus aureus, 0.25 and 4 microg/ml, respectively; Enterococcus faecalis, 0.5 and 32 microg/ml, respectively; and Staphylococcus aureus, 2 and 32 microg/ml, respectively. Generally, the UBTs for gram-positive uropathogens were higher for gemifloxacin than for ofloxacin and the UBTs for gram-negative uropathogens were higher for ofloxacin than for gemifloxacin. According to the UBTs, ofloxacin-resistant uropathogens (MICs, >or=4 mg/liter) should also be considered gemifloxacin resistant. Although clinical trials have shown that gemifloxacin is effective for the treatment of uncomplicated urinary tract infections, whether an oral dosage of 320 mg of gemifloxacin once daily is also adequate for the

  19. Bactericidal Property of the Benzalkonium Chloride in Industrial Circulating Water%洁儿灭在工业循环水中的杀菌性能研究

    Institute of Scientific and Technical Information of China (English)

    孙彩霞; 陈燕敏; 吴晋英; 黄长山

    2016-01-01

    In the thesis,the bactericidal property of benzalkonium chloride was tested by the method of plate counting. The bactericidal effciency was improved with increasing the concentration of benzalkonium chloride. At the same time the bacterial agent which prepared by the benzalkonium chloride had a better scale inbibtion effect , and could be sately applied to industrial circulating water pipeline system.%通过平板计数法考察了不同浓度的洁儿灭对工业循环水中异养菌的杀菌性能,结果显示,洁儿灭杀菌效率随着浓度的增加而增加,且由洁儿灭配制而成的杀菌剂阻垢性能较好,能安全地应用到工业循环水管道系统中。

  20. Expression of the K54 and O4 specific antigen has opposite effects on the bactericidal activity of squalamine against an extraintestinal isolate of Escherichia coli.

    Science.gov (United States)

    Russo, T A; Mylotte, D

    1998-05-15

    Squalamine is a novel cationic steroid that possesses potent, broad spectrum, antimicrobial activity. Recent data suggests that squalamine or related compounds may be present and important in host resistance to infection in the urinary tract. Therefore, the role of the K54 capsule and the O4 specific antigen moiety of the lipopolysaccharide in protecting an extraintestinal isolate of Escherichia coli against the bactericidal activity of this novel antimicrobial compound was studied. The O4 specific antigen was important for protection against squalamine. Surprisingly, in contrast, the presence of the K54 antigen enhanced the bactericidal activity of squalamine. This is the first example, to our knowledge, in which an established virulence trait, the K54 capsule, may be detrimental to an infecting pathogen under certain circumstances.

  1. Analysis on influence factor of bactericidal efficiencyin waste water%油田污水杀菌效果影响因素分析

    Institute of Scientific and Technical Information of China (English)

    唐永安

    2011-01-01

    Through investigation of the present SRB-content in wastewater station of Shengli oilfield,analyse the drug-resistant and putting means of bactericide.The influence factor of bactericidal efficiency is identified and how to improve the sterilization is pr%通过对胜利油田各污水站细菌含量现状调查以及胜利油田在用杀菌剂的抗药性、投加方式、使用效果分析,找出了影响杀菌剂杀菌效果的因素,对如何提高杀菌效果提出了自己的认识。

  2. 固载型季(鏻)盐的制备及其杀菌性能%Synthesis and bactericidal properties of a polymeric immobilized quaternary phosphonium actericide

    Institute of Scientific and Technical Information of China (English)

    张俊; 雷良才; 王思瑶; 郭磊; 张翔; 张金秋

    2011-01-01

    A polymeric immobilized quaternary phosphonium salt was synthesized by using chloromethylated polystyrene ( C1 content about 17% ) as carrier and reaction of Grignard reagent of 1-bromohexadecane with chlorodiphenyl phosphine, and its chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR) . By using standard plate counting method, the bactericide had high bactericidal efficiency, and the effects of main factors on immobilized ratio and bactericidal efficiency were studied. The experimental results showed that under appropriate condition,immobilized ratio could reach 9.2%, bactericidal ratio was 98.3% for 8 h, and this immobilized phosphonium salt could be reactivated by hydrochloric acid for re-use.%以溴代十六烷和镁屑制备的格氏试剂(Grignard reagent)与氯化二苯基膦反应得到十六烷基二苯基膦,用氯甲基聚苯乙烯(Cl含量约为17%)为载体进行固载反应,制备了固载型季(鏻)盐,并进行了结构表征.采用标准平皿计数法研究了固载型季(鏻)盐的杀菌性能,考察了反应时间,反应温度、交联的氯甲基聚苯乙烯溶胀时间对产物固载率和杀菌性能的影响.实验结果表明,在适宜的反应条件下,十六烷基二苯基膦在氯球上的固载率可达9.2%,此时制得的固栽型杀菌剂的杀菌率可达98.3%,且可重复使用.用稀盐酸进行活化恢复杀菌性能.

  3. Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite "Earth-plus"

    Directory of Open Access Journals (Sweden)

    Kasuga E

    2011-09-01

    Full Text Available Eriko Kasuga1,2, Yoshiyuki Kawakami2,3, Takehisa Matsumoto1, Eiko Hidaka1, Kozue Oana2, Naoko Ogiwara1, Dai Yamaki4, Tsukasa Sakurada4, Takayuki Honda1,51Department of Laboratory Medicine, Shinshu University Hospital, 2Division of Infection Control and Microbiological Regulation, Department of Health and Medical Sciences, Shinshu University Graduate School of Medicine, 3Division of Clinical Microbiology, Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University School of Medicine, 4Shinshu Ceramics Co Ltd, Kiso, Nagano, Japan; 5Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, JapanBackground: Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite "Earth-plus".Methods: Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains.Results: The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log10 colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3–6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours.Conclusion: Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric.Keywords: hydroxyapatite

  4. M.A.B. Vitreous coatings with bactericidal and fungicidal properties; M.A.B. Revestimientos vitreos con propiedades bactericidas y fungicidas

    Energy Technology Data Exchange (ETDEWEB)

    Cuoghi Fenollar, L.; Romero Valiente, J.; Villar Apellaniz, C.; Faubel Serra, V.; Noguera Orti, J. F.; Garcia Ten, J.; Yague Munoz, A.; Duran, A.

    2012-07-01

    This report describes the mosaic M.A.B. (bactericide and fungicide) produced by Togama S.A. belonging to the group Fluidra S.A., which has been awarded with the Silver Alfa Award by the Spanish Society of Ceramics and Glass at the International Fair Cevisama 2012. This award recognizes the R and D efforts developed by Togama, SA, already started with participation in the Alpha Awards 2009 and 2011. (Author)

  5. Short communication: minimum bactericidal concentration of disinfectants evaluated for bovine digital dermatitis-associated Treponema phagedenis-like spirochetes.

    Science.gov (United States)

    Hartshorn, R E; Thomas, E C; Anklam, K; Lopez-Benavides, M G; Buchalova, M; Hemling, T C; Döpfer, D

    2013-05-01

    The bacterial spirochetes, Treponema spp., are thought to be a major contributor to the etiology of bovine digital dermatitis (DD), a skin disease with worldwide economic impact. Hoofbath strategies are commonly used in an attempt to control and prevent the development of DD and continuing research has been done to develop an optimal hoofbath strategy for this purpose. The aim of this study was to develop a protocol that can be used as part of the screening process for candidate hoofbath disinfectants. This protocol allows an accurate determination of the in vitro minimum inhibitory concentration and minimum bactericidal concentration of a series of disinfectants for Treponema microorganisms. Assays were performed in triplicate for each of the disinfectants at 30-s and 10-min exposure times and exposed to 10 and 20% manure (vol/vol). The results of this study can be used to categorize disinfectants based on the effect of exposure and manure concentration regarding their ability to inhibit Treponema growth. This information can then aid in optimizing strategies for hoofbath-based control of DD development and spread.

  6. Synthesis and characterization of novel bactericidal Cu/HPMC BNCs using chemical reduction method for food packaging.

    Science.gov (United States)

    Ebrahimiasl, Saeideh; Rajabpour, Ataollah

    2015-09-01

    In this research copper nanoparticles (Cu NPs) were incorporated in the biodegradable hydroxypropyl methylcellulose (HPMC) matrix using the simple and low cost chemical reduction method for application as food packaging material. The properties of Cu/HPMC bionanocomposites (BNCs) were studied as a function of the CuSO4 concentration. Surface morphology of the film was investigated by scanning electron microscopy. Mechanical analysis and water vapor barrier properties of HPMC/Cu nanocomposites were analyzed. It was observed that mechanical and water vapor barrier properties of the films were improved by the concentration of CuSO4. The antibacterial activity of HPMC/Cu thin films were evaluated based on the diameter of inhibition zone in a disk diffusion test against Gram positive bacteria, ie, Streptococus A., S. epidermidis, S.aureus , B.cereus and Gram negative bacteria, ie, E. coli, E. faecalis, Salmonella, P. aeruginosa using Mueller Hinton agar at different concentration of CuSO4. The results revealed a greater bactericidal effectiveness for nanocomposite films containing 5 % of CuSO4. Packages prepared from HPMC/Cu nanocomposite films were used for meat packaging. The films were filled with meat and then stored at 4 °C. Microbial stability of the meat was evaluated after 3, 7, 10 and 15 days of storage. The results showed that microbial growth rate significantly reduced as a result of using this nanocomposite packaging material.

  7. Bactericidal activity and mechanism of action of copper-sputtered flexible surfaces against multidrug-resistant pathogens.

    Science.gov (United States)

    Ballo, Myriam K S; Rtimi, Sami; Mancini, Stefano; Kiwi, John; Pulgarin, César; Entenza, José M; Bizzini, Alain

    2016-07-01

    Using direct current magnetron sputtering (DCMS), we generated flexible copper polyester surfaces (Cu-PES) and investigated their antimicrobial activity against a range of multidrug-resistant (MDR) pathogens including eight Gram-positive isolates (three methicillin-resistant Staphylococcus aureus [MRSA], four vancomycin-resistant enterococci, one methicillin-resistant Staphylococcus epidermidis) and four Gram-negative strains (one extended-spectrum β-lactamase-producing [ESBL] Escherichia coli, one ESBL Klebsiella pneumoniae, one imipenem-resistant Pseudomonas aeruginosa, and one ciprofloxacin-resistant Acinetobacter baumannii). Bactericidal activity (≥3 log10 CFU reduction of the starting inoculum) was reached within 15-30 min exposure to Cu-PES. Antimicrobial activity of Cu-PES persisted in the absence of oxygen and against both Gram-positive and Gram-negative bacteria containing elevated levels of catalases, indicating that reactive oxygen species (ROS) do not play a primary role in the killing process. The decrease in cell viability of MRSA ATCC 43300 and Enterococcus faecalis V583 correlated with the progressive loss of cytoplasmic membrane integrity both under aerobic and anaerobic conditions, suggesting that Cu-PES mediated killing is primarily induced by disruption of the cytoplasmic membrane function. Overall, we here present novel antimicrobial copper surfaces with improved stability and sustainability and provide further insights into their mechanism of killing.

  8. Ambroxol inhibits mucoid conversion of Pseudomonas aeruginosa and contributes to the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms.

    Science.gov (United States)

    Wang, Wenlei; Yu, Jialin; He, Yu; Wang, Zhengli; Li, Fang

    2016-07-01

    Pseudomonas aeruginosa is an opportunistic human pathogen that can cause severe infections in immunocompromised individuals. Because it forms biofilms, which protect against host immune attack and increase resistance to conventional antibiotics, mucoid P. aeruginosa is nearly impossible to eradicate. Moreover, mucoid conversion of P. aeruginosa in cystic fibrosis (CF) patients leads to poor outcomes. This conversion is mainly due to mucA gene mutation, which is thought to be induced by polymorphonuclear leukocytes (PMNs) and the reactive oxygen species they release. Ambroxol, a mucolytic agent with antioxidant characteristics, is used clinically, and this compound has recently been demonstrated to possess anti-biofilm properties. In this study, we found that ambroxol inhibits the H2 O2 -mediated conversion of P. aeruginosa from a non-mucoid to a mucoid phenotype, an effect that is due to its antioxidant property against H2 O2 . Furthermore, the bactericidal activity of ciprofloxacin against mucoid P. aeruginosa biofilms was increased in vitro when used in combination with ambroxol.

  9. Bactericidal/Permeability-increasing protein fold-containing family member A1 in airway host protection and respiratory disease.

    Science.gov (United States)

    Britto, Clemente J; Cohn, Lauren

    2015-05-01

    Bactericidal/permeability-increasing protein fold-containing family member A1 (BPIFA1), formerly known as SPLUNC1, is one of the most abundant proteins in respiratory secretions and has been identified with increasing frequency in studies of pulmonary disease. Its expression is largely restricted to the respiratory tract, being highly concentrated in the upper airways and proximal trachea. BPIFA1 is highly responsive to airborne pathogens, allergens, and irritants. BPIFA1 actively participates in host protection through antimicrobial, surfactant, airway surface liquid regulation, and immunomodulatory properties. Its expression is modulated in multiple lung diseases, including cystic fibrosis, chronic obstructive pulmonary disease, respiratory malignancies, and idiopathic pulmonary fibrosis. However, the role of BPIFA1 in pulmonary pathogenesis remains to be elucidated. This review highlights the versatile properties of BPIFA1 in antimicrobial protection and its roles as a sensor of environmental exposure and regulator of immune cell function. A greater understanding of the contribution of BPIFA1 to disease pathogenesis and activity may clarify if BPIFA1 is a biomarker and potential drug target in pulmonary disease.

  10. Bactericidal activity and silver release of porous ceramic candle filter prepared by sintering silica with silver nanoparticles/zeolite for water disinfection

    Science.gov (United States)

    Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Thanh Nguyen, Duc; Hien Nguyen, Quoc

    2014-09-01

    Porous ceramic candle filters (PCCF) were prepared by sintering silica from rice husk with silver nanoparticles (AgNPs)/zeolite A at about 1050 °C to create bactericidal PCCF/AgNPs for water disinfection. The silver content in PCCF/AgNPs was of 300-350 mg kg-1 determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the average pore size of PCCF/AgNPs was of 50-70 Å measured by Brunauer-Emmett-Teller (BET) method. The bactericidal activity and silver release of PCCF/AgNPs have been investigated by flow test with water flow rate of 5 L h-1 and initial inoculation of E. coli in inlet water of 106 CFU/100 mL. The volume of filtrated water was collected up to 500 L. Results showed that the contamination of E. coli in filtrated water was water was low, far under the WHO guideline of 100 μg L-1 at maximum for drinking water. Based on the content of silver in PCCF/AgNPs and in filtrated water, it was estimated that one PCCF/AgNPs could be used to filtrate of ˜100 m3 water. Thus, as-prepared PCCF/AgNPs releases low content of silver into water and shows effectively bactericidal activity that is promising to apply as point-of-use water treatment technology for drinking water disinfection.

  11. Arginine in α-defensins: differential effects on bactericidal activity correspond to geometry of membrane curvature generation and peptide-lipid phase behavior.

    Science.gov (United States)

    Schmidt, Nathan W; Tai, Kenneth P; Kamdar, Karishma; Mishra, Abhijit; Lai, Ghee Hwee; Zhao, Kun; Ouellette, André J; Wong, Gerard C L

    2012-06-22

    The conserved tridisulfide array of the α-defensin family imposes a common triple-stranded β-sheet topology on peptides that may have highly diverse primary structures, resulting in differential outcomes after targeted mutagenesis. In mouse cryptdin-4 (Crp4) and rhesus myeloid α-defensin-4 (RMAD4), complete substitutions of Arg with Lys affect bactericidal peptide activity very differently. Lys-for-Arg mutagenesis attenuates Crp4, but RMAD4 activity remains mostly unchanged. Here, we show that the differential biological effect of Lys-for-Arg replacements can be understood by the distinct phase behavior of the experimental peptide-lipid system. In Crp4, small-angle x-ray scattering analyses showed that Arg-to-Lys replacements shifted the induced nanoporous phases to a different range of lipid compositions compared with the Arg-rich native peptide, consistent with the attenuation of bactericidal activity by Lys-for-Arg mutations. In contrast, such phases generated by RMAD4 were largely unchanged. The concordance between small-angle x-ray scattering measurements and biological activity provides evidence that specific types of α-defensin-induced membrane curvature-generating tendencies correspond directly to bactericidal activity via membrane destabilization.

  12. Outer membrane mutants of Salmonella typhimurium LT2 have lipopolysaccharide-dependent resistance to the bactericidal activity of anaerobic human neutrophils.

    Science.gov (United States)

    Okamura, N; Spitznagel, J K

    1982-06-01

    The capacity of neutrophil polymorphonuclear granulocytes (PMNs) to phagocytize bacteria under anaerobic as well as aerobic conditions afforded the opportunity to compare the bactericidal activities of oxygen-independent and oxygen-dependent antimicrobial mechanisms in human PMNs challenged with Salmonella typhimurium LT2 and its lipopolysaccharide mutants (outer membrane mutants). Anaerobic human PMNs challenged with either opsonized LT2 or serum-treated zymosan failed to produce detectable superoxide anion (O2-) or to reduce nitroblue tetrazolium, although aerobic PMNs readily produced O2- in response to such challenge. Anaerobic PMNs killed these bacteria in an ordered fashion that appeared to be dependent on their lipopolysaccharide chemotype. As the carbohydrate content of the mutant lipopolysaccharide decreased, the bacteria became less resistant to the oxygen-independent bactericidal activity. The results resembled the ordered resistance to oxygen-independent killing observed with LT2 and its mutants in PMN-free systems with PMN granule proteins. Studies on the kinetics of killing showed these to be less rapid in anaerobic as compared with aerobic conditions. Opsonization increased the rate of phagocytosis, but such factors as opsonization and the rate of phagocytosis did not appear to affect intraleukocytic bactericidal capacity in that the resultant proportion of bacteria remaining viable after ingestion was similar regardless of which serum was used (normal serum, C6-deficient serum, C8-deficient serum, or no serum at all). The results are consistent with an active and substantial participation by oxygen-independent systems in the antimicrobial effects of neutrophils.

  13. Novel antiseptic compound OPB-2045G shows potent bactericidal activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus both in vitro and in vivo: a pilot study in animals.

    Science.gov (United States)

    Inoue, Yasuhide; Hagi, Akifumi; Nii, Takuya; Tsubotani, Yoshie; Nakata, Hikaru; Iwata, Koushi

    2015-01-01

    There is a need for new compounds to effectively treat methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). The novel monobiguanide compound 1-(3,4-dichlorobenzyl)-5-octylbiguanide gluconate (OPB-2045G) has potential bactericidal activity. We sought to elucidate the potency of OPB-2045G bactericidal activity against MRSA and VRE compared to those of chlorhexidine digluconate (CHG) and povidone iodine (PVP-I). In vitro bactericidal activity was analysed using minimum bactericidal concentration (MBC) as the index. The in vivo bactericidal efficacy of OPB-2045G was examined by determining MRSA and VRE contamination of the normal dorsal skin of mice following removal of hair. After a 3 min treatment period, the MBC of OPB-2045G was lower than that of CHG and PVP-I against standard strains and clinical isolates. Additionally, in our in vivo mouse model, the in vivo bactericidal activity of 1.5 % OPB-2045G (a clinically relevant dose) was higher than that of 0.5 % CHG and equivalent to that of 10 % PVP-I against MRSA. Similarly, the in vivo bactericidal activity of OPB-2045G was higher than that of 0.5 % CHG and 10 % PVP-I against VRE. OPB-2045G showed more potent bactericidal activity against MRSA and VRE both in vitro and in vivo compared to CHG and PVP-I, indicating that OPB-2045G may provide better protection against health care-associated infections caused by these pathogens.

  14. The bactericidal effect of 470-nm light and hyperbaric oxygen on methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Bumah, Violet Vakunseh; Whelan, Harry Thomas; Masson-Meyers, Daniela Santos; Quirk, Brendan; Buchmann, Ellen; Enwemeka, Chukuka Samuel

    2015-04-01

    It has been shown that, in vitro, hyperbaric oxygen (HBO) suppresses 28 % bacterial growth, while 470-nm blue light alone suppresses up to 92 % methicillin-resistant Staphylococcus aureus (MRSA) in one application in vitro. Therefore, we determined if combined 470-nm light (55 J/cm(2)) and HBO will yield 100 % bacterial suppression in experimental simulation of mild, moderate or severe MRSA infection. We cultured MRSA at 3 × 10(6), 5 × 10(6), 7 × 10(6), 8 × 10(6), or 12 × 10(6) CFU/ml and treated each concentration in four groups as follows: (1) control (no treatment) (2) photo-irradiation only, (3) photo-irradiation then HBO, (4) HBO only, and (5) HBO then photo-irradiation. Bacteria colonies were then quantified. The results showed that at each bacterial concentration, HBO alone was significantly less effective in suppressing MRSA than photo-irradiation or combined HBO and photo-irradiation (p  0.05), neither did HBO treatment either before or after irradiation make a difference. Furthermore, at no bacterial concentration was 100 % MRSA suppression achieved. Indeed, the maximum bacterial suppression attained was in the mild infection model (3 × 10(6) CFU/ml), with blue light producing 97.3 ± 0.2 % suppression and HBO + 55 J/cm(2) yielding 97.5 ± 2.5 % suppression. We conclude that (1) HBO and 470-nm light individually suppress MRSA growth; (2) 470-nm blue light is more effective in suppressing MRSA than HBO; and (3) HBO did not act synergistically to heighten the bactericidal effect of 470-nm light.

  15. Peroxiredoxin-6 Negatively Regulates Bactericidal Activity and NF-κB Activity by Interrupting TRAF6-ECSIT Complex

    Science.gov (United States)

    Min, Yoon; Wi, Sae M.; Shin, Dongwoo; Chun, Eunyoung; Lee, Ki-Young

    2017-01-01

    A TRAF6-ECSIT complex is crucial for the generation of mitochondrial reactive oxygen species (mROS) and nuclear factor-kappa B (NF-κB) activation induced by Toll-like receptor 4 (TLR4). Peroxiredoxin-6 (Prdx6) as a member of the peroxiredoxin family of antioxidant enzymes is involved in antioxidant protection and cell signaling. Here, we report on a regulatory role of Prdx6 in mROS production and NF-κB activation by TLR4. Prdx6 was translocated into the mitochondria by TLR4 stimulation and Prdx6-knockdown (Prdx6KD) THP-1 cells had increased level of mitochondrial reactive oxygen species levels and were resistant to Salmonella typhimurium infection. Biochemical studies revealed Prdx6 interaction with the C-terminal TRAF-C domain of TRAF6, which drove translocation into the mitochondria. Interestingly, Prdx6 competitively interacted with ECSIT to TRAF6 through its C-terminal TRAF-C domain, leading to the interruption of TRAF6-ECSIT interaction. The inhibitory effect was critically implicated in the activation of NF-κB induced by TLR4. Overexpression of Prdx6 led to the inhibition of NF-κB induced by TLR4, whereas Prdx6KD THP-1 cells displayed enhanced production of pro-inflammatory cytokines including interleukin-6 and -1β, and the up-regulation of NF-κB-dependent genes induced by TLR4 stimulation. Taken together, the data demonstrate that Prdx6 interrupts the formation of TRAF6-ECSIT complex induced by TLR4 stimulation, leading to suppression of bactericidal activity because of inhibited mROS production in mitochondria and the inhibition of NF-κB activation in the cytoplasm.

  16. Electrochemical synthesis of multi-armed CuO nanoparticles and their remarkable bactericidal potential against waterborne bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Pratibha, E-mail: rkpratibha@yahoo.com; Merwyn, S.; Agarwal, G. S.; Tripathi, B. K.; Pant, S. C. [Defence Research and Development Establishment (India)

    2012-01-15

    Copper (II) oxide multi-armed nanoparticles composed of 500-1000 nm long radiating nanospicules with 100-200 nm width near the base and 50-100 nm width at the tapered ends and {approx}25 nm thickness were synthesized by electrochemical deposition in the presence of an oxidant followed by calcination at 150 Degree-Sign C. The nanoparticles were characterized using SEM/EDX for morphology and composition, Raman spectroscopy for compound identification, and broth culture method for antibacterial efficacy. The CuO nanoparticles have shown remarkable bactericidal efficacy against Gram-positive and -negative waterborne disease causing bacteria like Escherichia coli, Salmonella typhi, staphylococcus aureus and Bacillus subtilis. E. coli has been chosen as representative species for waterborne disease causing bacteria. In antibacterial tests 500 {mu}g/mL nano CuO killed 3 Multiplication-Sign 10{sup 8} CFU/mL E. coli bacteria within 4 h of exposure. Moreover, 8.3 Multiplication-Sign 10{sup 6} CFU/mL E. coli were killed by 100 and 10 {mu}g/mL nano CuO within 15 min and 4 h of exposure, respectively. Antibacterial activity of nano CuO has been found many-fold compared with commercial bulk CuO. The fate of nanoparticles after antibacterial test has also been studied. The synthesized CuO nanoparticles are expected to have potential antibacterial applications in water purification and in paints and coatings used on frequently touched surfaces and fabrics in hospital settings.

  17. Periowave demonstrates bactericidal activity against periopathogens and leads to improved clinical outcomes in the treatment of adult periodontitis

    Science.gov (United States)

    Street, Cale N.; Andersen, Roger; Loebel, Nicolas G.

    2009-02-01

    Periodontitis affects half of the U.S. population over 50, and is the leading cause of tooth loss after 35. It is believed to be caused by growth of complex bacterial biofilms on the tooth surface below the gumline. Photodynamic therapy, a technology used commonly in antitumor applications, has more recently been shown to exhibit antimicrobial efficacy. We have demonstrated eradication of the periopathogens Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans in vitro using PeriowaveTM; a commercial photodisinfection system. In addition, several clinical studies have now demonstrated the efficacy of this treatment. A pilot study in the U.S. showed that 68% of patients treated with PeriowaveTM adjunctively to scaling and root planing (SRP) showed clinical attachment level increase of >1 mm, as opposed to 30% with SRP alone. In a subsequent larger study, a second PeriowaveTM treatment 6 weeks after initial treatment led to pocket depth improvements of >1.5 mm in 89% of patients. Finally, in the most recent multicenter, randomized, examiner-blinded study conducted on 121 subjects in Canada, PeriowaveTM treatment produced highly significant gains in attachment level (0.88 mm vs. 0.57 mm; p=0.003) and pocket depth (0.87 mm vs. 0.63 mm; p=0.01) as compared to SRP alone. In summary, PeriowaveTM demonstrated strong bactericidal activity against known periopathogens, and treatment of periodontitis using this system produced significantly better clinical outcomes than SRP alone. This, along with the absence of any adverse events in patients treated to date demonstrates that PDT is a safe and effective treatment for adult chronic periodontitis.

  18. Dynamic Mechanisms of the Bactericidal Action of an Al2O3-TiO2-Ag Granular Material on an Escherichia coli Strain.

    Science.gov (United States)

    Tartanson, Marie-Anne; Soussan, Laurence; Rivallin, Matthieu; Pecastaings, Sophie; Chis, Cristian V; Penaranda, Diego; Roques, Christine; Faur, Catherine

    2015-10-01

    The bactericidal activity of an Al2O3-TiO2-Ag granular material against an Escherichia coli strain was confirmed by a culture-based method. In particular, 100% of microorganisms were permanently inactivated in 30 to 45 min. The present work aimed to investigate the mechanisms of the bactericidal action of this material and their dynamics on Escherichia coli using different techniques. Observations by transmission electron microscopy (TEM) at different times of disinfection revealed morphological changes in the bacteria as soon as they were put in contact with the material. Notably highlighted were cell membrane damage; cytoplasm detachment; formation of vacuoles, possibly due to DNA condensation, in association with regions exhibiting different levels of electron density; and membrane lysis. PCR and flow cytometry analyses were used to confirm and quantify the observations of cell integrity. The direct exposure of cells to silver, combined with the oxidative stress induced by the reactive oxygen species (ROS) generated, was identified to be responsible for these morphological alterations. From the first 5 min of treatment with the Al2O3-TiO2-Ag material, 98% of E. coli isolates were lysed. From 30 min, cell viability decreased to reach total inactivation, although approximately 1% of permeable E. coli cells and 1% of intact cells (10(5) genomic units·ml(-1)) were evidenced. This study demonstrates that the bactericidal effect of the material results from a synergic action of desorbed and supported silver. Supported silver was shown to generate the ROS evidenced.

  19. Development of the Bactericidal Treatment Room with High Electromagnetic Pulse Field%电磁脉冲高场强杀菌处理室的研制

    Institute of Scientific and Technical Information of China (English)

    解效白; 陈炜峰

    2012-01-01

    The pulsed electric field sterilization (Pulsed Electric Field,PEF) technology is a promising nonthermal sterilization science. The processing chamber which is the key component of the PEF directly influences the bactericidal effect. According to the principle of transmission line characteristic, the paper designed a coaxial processing chamber with impedance of 75 ohms and field strength of 50 kV/cm, and the treatment room was used to do the bactericidal test. The results showed that the processing chamber and the electromagnetic pulse source are well matched, the association of sterilization rate of the pulse peak voltage and irradiation pulse number is large,which can be used in the pilot study of the bactericidal mechanism.%脉冲电场杀菌技术是一项极具前景的食品非热杀菌技术,其处理关键部件——处理室直接影响杀菌效果.根据传输线原理,设计了特性阻抗为75Ω,场强可达到50kV/cm的同轴式处理室,并利用该处理室进行了杀菌试验.结果表明,处理室与电磁脉冲源匹配良好,杀菌率与脉冲峰值电压以及照射脉冲个数的关联度较大,可以用于杀菌机理的试验研究.

  20. Natural product derivatives with bactericidal activity against Gram-positive pathogens including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis.

    Science.gov (United States)

    Phillips, Joshua B; Smith, Adrienne E; Kusche, Brian R; Bessette, Bradley A; Swain, P Whitney; Bergmeier, Stephen C; McMills, Mark C; Wright, Dennis L; Priestley, Nigel D

    2010-10-01

    We have shown that the intentional engineering of a natural product biosynthesis pathway is a useful way to generate stereochemically complex scaffolds for use in the generation of combinatorial libraries that capture the structural features of both natural products and synthetic compounds. Analysis of a prototype library based upon nonactic acid lead to the discovery of triazole-containing nonactic acid analogs, a new structural class of antibiotic that exhibits bactericidal activity against drug resistant, Gram-positive pathogens including Staphylococcus aureus and Enterococcus faecalis.

  1. Silver-loaded nanotubular structures enhanced bactericidal efficiency of antibiotics with synergistic effect in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Xu N

    2017-01-01

    -positive Staphylococcus aureus (ATCC 25923, and methicillin-resistant Staphylococcus aureus (MRSA; ATCC 33591 and ATCC 43300. Moreover, after a relative short (3 weeks combinational treatment, animal experiments in vivo further proved the synergistic antibacterial effect by X-ray and histological and immunohistochemical analyses. These results demonstrated that the combination of Ag nanoparticles and antibiotics significantly enhanced the antibacterial effect both in vitro and in vivo through the synergistic effect. The strategy is promising for clinical application to reduce the usage of antibiotics and shorten the administration time of implant-associated infection. Keywords: implant-associated infection, silver nanoparticles, TiO2 nanotube, antibiotics, synergistic bactericidal activity

  2. Helicobacter pylori CagA triggers expression of the bactericidal lectin REG3γ via gastric STAT3 activation.

    Directory of Open Access Journals (Sweden)

    Kai Syin Lee

    Full Text Available BACKGROUND: Most of what is known about the Helicobacter pylori (H. pylori cytotoxin, CagA, pertains to a much-vaunted role as a determinant of gastric inflammation and cancer. Little attention has been devoted to potential roles of CagA in the majority of H. pylori infected individuals not showing oncogenic progression, particularly in relation to host tolerance. Regenerating islet-derived (REG3γ encodes a secreted C-type lectin that exerts direct bactericidal activity against Gram-positive bacteria in the intestine. Here, we extend this paradigm of lectin-mediated innate immunity, showing that REG3γ expression is triggered by CagA in the H. pylori-infected stomach. METHODOLOGY/PRINCIPAL FINDINGS: In human gastric mucosal tissues, REG3γ expression was significantly increased in CagA-positive, compared to CagA-negative H. pylori infected individuals. Using transfected CagA-inducible gastric MKN28 cells, we recapitulated REG3γ induction in vitro, also showing that tyrosine phosphorylated, not unphosphorylated CagA triggers REG3γ transcription. In concert with induced REG3γ, pro-inflammatory signalling downstream of the gp130 cytokine co-receptor via the signal transducer and activator of transcription (STAT3 and transcription of two cognate ligands, interleukin(IL-11 and IL-6, were significantly increased. Exogenous IL-11, but not IL-6, directly stimulated STAT3 activation and REG3γ transcription. STAT3 siRNA knockdown or IL-11 receptor blockade respectively abrogated or subdued CagA-dependent REG3γ mRNA induction, thus demonstrating a requirement for uncompromised signalling via the IL-11/STAT3 pathway. Inhibition of the gp130-related SHP2-(Ras-ERK pathway did not affect CagA-dependent REG3γ induction, but strengthened STAT3 activation as well as augmenting transcription of mucosal innate immune regulators, IL-6, IL-8 and interferon-response factor (IRF1. CONCLUSIONS/SIGNIFICANCE: Our results support a model of CagA-directed REG3

  3. Plantaricin IIA-1A5 from Lactobacillus plantarum IIA-1A5 displays bactericidal activity against Staphylococcus aureus.

    Science.gov (United States)

    Arief, I Isnafia; Budiman, C; Jenie, B Sri Laksmi; Andreas, E; Yuneni, A

    2015-01-01

    Plantaricin IIA-1A5 is a bacteriocin produced by Lactobacillus plantarum IIA-1A5 isolated from Indonesian beef. This research aimed to identify the genes involved in plantaricin IIA-1A5 production and examine its mode of action against Staphylococcus aureus. It has been reported that a bacteriocin structural gene, plnW, is present in genome of L. plantarum IIA-1A5. Here, we reported the presence of additional genes responsible for plantaricin precursor (plnA and plnEF) and a gene encoding the quorum sensor of histidine kinase (plnB). It indicates that genes involved in production of plantaricin IIA-1A5 are organized in at least two bacteriocin operons (plnABCD, plnEFI) and a structural plnW gene. Purified plantaricin IIA-1A5 yielded a single band in SDS-PAGE with apparent size of 6.4 kDa. Amino acid composition of purified plantaricin IIA-1A5 was mainly composed of cationic glutamic acid and cysteine that allowed the formation of disulphide bonds, suggesting plantaricin IIA-1A5 belongs to the pediocin-subclass of class II bacteriocins. Plantaricin IIA-1A5 displayed remarkable antibacterial activity against S. aureus, which was initiated by the adsorption of plantaricin IIA-1A5 onto the cell membrane of S. aureus. The adsorption is hypothesised to be facilitated by non-ionic interactions as it is reduced by the presence of organic solvents or detergents. This adsorption promoted leakage of cellular metabolites through the cell membrane of S. aureus, as indicated by the release of genetic and proteinaceous material of S. aureus observed at 260 and 280 nm, respectively. The leakage also promoted the release of divalent (Ca(2+), Mg(2+)) and monovalent (K(+)) cations. The release of these intracellular components might be due to pores formed in the cell membrane of S. aureus by plantaricin IIA-1A5 as shown by scanning electron microscopy. Altogether, the mode of action of plantaricin IIA-1A5 against S. aureus seems to be bactericidal as indicated by lysis of the cell

  4. Aging Enhances the Production of Reactive Oxygen Species and Bactericidal Activity in Peritoneal Macrophages by Upregulating Classical Activation Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Smallwood, Heather S.; López-Ferrer, Daniel; Squier, Thomas C.

    2011-10-07

    Maintenance of macrophages in their basal state and their rapid activation in response to pathogen detection are central to the innate immune system, acting to limit nonspecific oxidative damage and promote pathogen killing following infection. To identify possible age-related alterations in macrophage function, we have assayed the function of peritoneal macrophages from young (3–4 months) and aged (14–15 months) Balb/c mice. In agreement with prior suggestions, we observe age-dependent increases in the extent of recruitment of macrophages into the peritoneum, as well as ex vivo functional changes involving enhanced nitric oxide production under resting conditions that contribute to a reduction in the time needed for full activation of senescent macrophages following exposure to lipopolysaccharides (LPS). Further, we observe enhanced bactericidal activity following Salmonella uptake by macrophages isolated from aged Balb/c mice in comparison with those isolated from young animals. Pathways responsible for observed phenotypic changes were interrogated using tandem mass spectrometry, which identified age-dependent increases in levels of proteins linked to immune cell pathways under basal conditions and following LPS activation. Immune pathways upregulated in macrophages isolated from aged mice include proteins critical to the formation of the immunoproteasome. Detection of these latter proteins is dramatically enhanced following LPS exposure for macrophages isolated from aged animals; in comparison, the identification of immunoproteasome subunits is insensitive to LPS exposure for macrophages isolated from young animals. Consistent with observed global changes in the proteome, quantitative proteomic measurements indicate that there are age-dependent abundance changes involving specific proteins linked to immune cell function under basal conditions. LPS exposure selectively increases the levels of many proteins involved in immune cell function in aged Balb/c mice

  5. The Neisseria meningitidis Macrophage Infectivity Potentiator Protein Induces Cross-Strain Serum Bactericidal Activity and Is a Potential Serogroup B Vaccine Candidate ▿

    Science.gov (United States)

    Hung, Miao-Chiu; Salim, Omar; Williams, Jeannette N.; Heckels, John E.; Christodoulides, Myron

    2011-01-01

    A gene encoding a 29-kDa protein from Neisseria meningitidis serogroup B strain MC58 with homology to the macrophage infectivity potentiator (MIP) protein of Legionella pneumophila was cloned and expressed in Escherichia coli, and the purified soluble recombinant protein (rMIP) was used for immunization studies. Analysis of the predicted amino acid sequences of MIP from 13 well-characterized meningococcal strains, isolated from carriers or patients and differing in serogroup, serotype, and subtype, showed that the protein was highly conserved (98 to 100%), with only three distinct sequence types (designated I, II, and III) found. Western blotting showed that the MIP protein was expressed at similar levels by all of these strains. Immunization of mice with type I MC58 rMIP in detergent micelles and liposomes containing monophosphoryl lipid A (MPLA) induced high levels of surface-reactive antibodies with serum bactericidal activity (SBA) titers of 1/1,024 against the homologous strain. Bactericidal antibodies were also induced with the protein in saline alone and liposomes alone (titers, 1/128) but not following adsorption to Al(OH)3. Significantly, antisera raised against type I rMIP administered in saline or liposomes killed strains of heterologous sequence types II and III with similar SBA titers (1/128 to 1/256). Taken together, these findings suggest that rMIP can provide cross-strain protection against meningococci and should be considered a potential antigen for inclusion in new vaccines against meningococcal infection. PMID:21708989

  6. The Neisseria meningitidis macrophage infectivity potentiator protein induces cross-strain serum bactericidal activity and is a potential serogroup B vaccine candidate.

    Science.gov (United States)

    Hung, Miao-Chiu; Salim, Omar; Williams, Jeannette N; Heckels, John E; Christodoulides, Myron

    2011-09-01

    A gene encoding a 29-kDa protein from Neisseria meningitidis serogroup B strain MC58 with homology to the macrophage infectivity potentiator (MIP) protein of Legionella pneumophila was cloned and expressed in Escherichia coli, and the purified soluble recombinant protein (rMIP) was used for immunization studies. Analysis of the predicted amino acid sequences of MIP from 13 well-characterized meningococcal strains, isolated from carriers or patients and differing in serogroup, serotype, and subtype, showed that the protein was highly conserved (98 to 100%), with only three distinct sequence types (designated I, II, and III) found. Western blotting showed that the MIP protein was expressed at similar levels by all of these strains. Immunization of mice with type I MC58 rMIP in detergent micelles and liposomes containing monophosphoryl lipid A (MPLA) induced high levels of surface-reactive antibodies with serum bactericidal activity (SBA) titers of 1/1,024 against the homologous strain. Bactericidal antibodies were also induced with the protein in saline alone and liposomes alone (titers, 1/128) but not following adsorption to Al(OH)(3). Significantly, antisera raised against type I rMIP administered in saline or liposomes killed strains of heterologous sequence types II and III with similar SBA titers (1/128 to 1/256). Taken together, these findings suggest that rMIP can provide cross-strain protection against meningococci and should be considered a potential antigen for inclusion in new vaccines against meningococcal infection.

  7. Synergistic bactericidal action of phytic acid and sodium chloride against Escherichia coli O157:H7 cells protected by a biofilm.

    Science.gov (United States)

    Kim, Nam Hee; Rhee, Min Suk

    2016-06-16

    The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22°C for 6days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (pbiofilm effect of PA was significantly increased by addition of NaCl (2-4%) (pbiofilms without recovery (a>6.5logCFU/cm(2) reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7logCFU/cm(2) reduction; NaCl, food safety managers who encounter thick biofilm formation in food processing environments.

  8. Bactericidal activity of juvenile chinook salmon macrophages against Aeromonas salmonicida after exposure to live or heat-killed Renibacterium salmoninarum or to soluble proteins produced by R. salmoninarum

    Science.gov (United States)

    Siegel, D.C.; Congleton, J.L.

    1997-01-01

    Macrophages isolated from the anterior kidney of juvenile chinook salmon Oncorhynchus tshawytscha in 96-well microtiter plates were exposed for 72 h to 0, 105, or 106 live or heat-killed Renibacterium salmoninarum cells per well or to 0, 0.1, 1.0, or 10 ??g/mL of R. salmoninarum soluble proteins. After treatment, the bactericidal activity of the macrophages against Aerornonas salmonicida was determined by a colorimetric assay based on the reduction of the tetrazolium dye MTT to formazan by viable bacteria. The MTT assay was modified to allow estimation of the percentage of bacteria killed by reference to a standard curve relating the number of bacteria added to microtiter wells to absorbance by formazan at 600 nm. The live and heat-killed R. salmoninarum treatments significantly (P < 0.001) increased killing of A. salmonicida by chinook salmon macrophages. In each of the five trials, significantly (P < 0.05) greater increases in killing occurred after exposure to 105 R. salmoninarum cells than to 106 R. salmoninarum cells per well. In contrast, treatment of macrophages with 10 ??g/mL R. salmoninarum soluble proteins significantly (P < 0.001) decreased killing of A. salmonicida, but treatment with lower doses did not. These results show that the bactericidal activity of chinook salmon macrophages is stimulated by exposure to R. salmoninarum cells at lower dose levels but inhibited by exposure to R. salmoninarum cells or soluble proteins at higher dose levels.

  9. Human Lysozyme Synergistically Enhances Bactericidal Dynamics and Lowers the Resistant Mutant Prevention Concentration for Metronidazole to Helicobacter pylori by Increasing Cell Permeability

    Directory of Open Access Journals (Sweden)

    Xiaolin Zhang

    2016-10-01

    Full Text Available Metronidazole (MNZ is an effective agent that has been employed to eradicate Helicobacter pylori (H. pylori. The emergence of broad MNZ resistance in H. pylori has affected the efficacy of this therapeutic agent. The concentration of MNZ, especially the mutant prevention concentration (MPC, plays an important role in selecting or enriching resistant mutants and regulating therapeutic effects. A strategy to reduce the MPC that can not only effectively treat H. pylori but also prevent resistance mutations is needed. H. pylori is highly resistant to lysozyme. Lysozyme possesses a hydrolytic bacterial cell wall peptidoglycan and a cationic dependent mode. These effects can increase the permeability of bacterial cells and promote antibiotic absorption into bacterial cells. In this study, human lysozyme (hLYS was used to probe its effects on the integrity of the H. pylori outer and inner membranes using as fluorescent probe hydrophobic 1-N-phenyl-naphthylamine (NPN and the release of aspartate aminotransferase. Further studies using a propidium iodide staining method assessed whether hLYS could increase cell permeability and promote cell absorption. Finally, we determined the effects of hLYS on the bactericidal dynamics and MPC of MNZ in H. pylori. Our findings indicate that hLYS could dramatically increase cell permeability, reduce the MPC of MNZ for H. pylori, and enhance its bactericidal dynamic activity, demonstrating that hLYS could reduce the probability of MNZ inducing resistance mutations.

  10. Surface functionalization of Cu-Ni alloys via grafting of a bactericidal polymer for inhibiting biocorrosion by Desulfovibrio desulfuricans in anaerobic seawater.

    Science.gov (United States)

    Yuan, S J; Liu, C K; Pehkonen, S O; Bai, R B; Neoh, K G; Ting, Y P; Kang, E T

    2009-01-01

    A novel surface modification technique was developed to provide a copper nickel alloy (M) surface with bactericidal and anticorrosion properties for inhibiting biocorrosion. 4-(chloromethyl)-phenyl tricholorosilane (CTS) was first coupled to the hydroxylated alloy surface to form a compact silane layer, as well as to confer the surface with chloromethyl functional groups. The latter allowed the coupling of 4-vinylpyridine (4VP) to generate the M-CTS-4VP surface with biocidal functionality. Subsequent surface graft polymerization of 4VP, in the presence of benzoyl peroxide (BPO) initiator, from the M-CTS-4VP surface produced the poly(4-vinylpyridine) (P(4VP)) grafted surface, or the M-CTS-P(4VP) surface. The pyridine nitrogen moieties on the M-CTS-P(4VP) surface were quaternized with hexylbromide to produce a high concentration of quaternary ammonium groups. Each surface functionalization step was ascertained by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurements. The alloy with surface-quaternized pyridinium cation groups (N+) exhibited good bactericidal efficiency in a Desulfovibrio desulfuricans-inoculated seawater-based modified Barr's medium, as indicated by viable cell counts and fluorescence microscopy (FM) images of the surface. The anticorrosion capability of the organic layers was verified by the polarization curve and electrochemical impedance spectroscopy (EIS) measurements. In comparison, the pristine (surface hydroxylated) Cu-Ni alloy was found to be readily susceptible to biocorrosion under the same environment.

  11. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti-Ag and Nb-Ag thin films.

    Science.gov (United States)

    Wojcieszak, D; Mazur, M; Kaczmarek, D; Mazur, P; Szponar, B; Domaradzki, J; Kepinski, L

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti-Ag and Nb-Ag thin films have been carried out. Ti-Ag and Nb-Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti-Ag and Nb-Ag thin films were nanocrystalline. In the case of Ag-Ti film presence of AgTi3 and Ag phases was identified, while in the structure of Nb-Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb-Ag thin films was covered with Ag-agglomerates, while Ti-Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h.

  12. 打瓜白粉病药剂防治技术研究%Study on the Technique of Controling Seed- used Watermelon Powdery Mildew with Bactericides

    Institute of Scientific and Technical Information of China (English)

    韩盛; 李新辉; 于建新; 王艳; 杨渡; 李承业; 潘竟海; 李妍娥; 杨静飞; 严丽; 刘同业; 侯秀芳

    2012-01-01

    [ Objective ] Because seed - used watermelon powdery mildew induced serious damage in Xinjiang Region, we study the control efficacy of six bactericides to seed - used watermelon powdery mildew in the field. [Method] Comparison of the control efficacy of six bactericides to seed -used watermelon powdery mildew was made in the field plot experiment. [Result]Fourteen days after using these bactericides twice, thecontrol efficacy of 10% ZJ0712 wp 5 ,000 times solution is 73. 80% , achieving the highest control efficacy in all the six used bactericides And the control efficacy of 10% ZJ0712 wp 1,0000 times solution, 50% Kresoxim - methyl WG 3 ,000 times solution, 400 g/L Flusilazole EC 7 ,500 times solution and 25% Ethirimol wp 1,500 times solution are also effective, reaching the effect of 69. 69% , 69.56% , 68. 48% , and 67. 32% respectively after being used 14 days later. [ Conclusion]The control efficacy of ZJ0712 wp, 50% Kresoxim - methyl WG, 400 g/L Flusilazole EC and 25% Ethirimol wp are quite effective, so it is suggested that they could be used in production by turn, and the rule for controlling seed - used watermelon powdery mildew is made. The primary sources of infection and suitable time for controlling this disease have been clearly made, too. The key to controlling seed - used watermelon powdery mildew is to spray effective bactericide in time.%[目的]针对打瓜白粉病在新疆严重危害的现状,研究6种杀菌剂对打瓜白粉病的田间防治效果.[方法]采用田间小区试验,比较6种药剂的防效差异.[结果]两次施药后第14 d,10%苯醚菌酯悬浮剂5000倍液防效最高,防效达73.80%.10%苯醚菌酯悬浮剂10 000倍液、50%醚菌酯水分散粒剂3 000倍液、400 g/L氟硅唑乳油7 500倍液和25%乙嘧酚悬浮剂1 500倍液的防效也较好,药后14 d分别达69.69%、69.56%、68.48%和67.32%.[结论]4种药剂防效较好,推荐在生产中交替使用.提出了打瓜白粉病防治原则,明

  13. 杀菌剂类农药的太赫兹光谱分类万法%Terahertz spectroscopy cluster analysis of four kinds of bactericide

    Institute of Scientific and Technical Information of China (English)

    马冶浩; 王强; 王孝伟; 谷小红

    2012-01-01

    A new cluster analysis method for bactericide spectrum was put forward on which wavelet packet and Euclidean distance were applied. The terahertz time - domain spectroscopy ( THz - TDS) was a newly developing spectroscopy technique base on ultrafast laser technology. Four kinds of bactericide ( ferric dimethyldithiocarbamate, carbendazim, captan, thiabendazole) were measured by THz - TDS to obtain their terahertz spectrums. Then the terahertz time - domain spectrums of samples were decomposed by wavelet packet transform. The wavelet packet energy spectrum were calculated, which were considered as feature vectors for cluster analysis. The experimental result shows that this method is able to successfully classify the bactericides terahertz spectrum based on wavelet packet and Euclidean distance.%提出一种新的针对杀菌剂类农药太赫兹光谱的分类方法,即用小波包变换来对杀菌剂太赫兹光谱进行特征提取,然后用欧式距离法对4种农药选行分类.太赫兹时域光谱(THz-TDS)技术是一种由超快激光技术快速发展起来的无损检测技术,利用太赫兹时域光谱系统对4种杀菌剂,即福美铁、多菌灵、克菌丹、噻菌灵进行了检测,得到了4种药品的太赫兹时域光谱.用小波包对农药时域光谱进行分解,计算小波包能量谱,并把能量谱作为聚类分析的特征向量,用欧式距离法对杀菌剂太赫兹光谱进行分类,实验结果表明,该方法可以有效地对杀菌剂进行分类.

  14. Oral Immunization of Rabbits with S. enterica Typhimurium Expressing Neisseria gonorrhoeae Filamentous Phage Φ6 Induces Bactericidal Antibodies Against N. gonorrhoeae.

    Science.gov (United States)

    Piekarowicz, Andrzej; Kłyż, Aneta; Majchrzak, Michał; Stein, Daniel C

    2016-03-04

    All Neisseria gonorrhoeae strains whose DNA sequences have been determined possess filamentous phage DNA sequences. To ascertain if phage encoded proteins could form the basis of a gonococcal vaccine, rabbits were orally infected with S. enterica Typhimurium strain χ3987 harboring phagemid NgoΦ6 fm. The elicited sera contained large quantities of anti-phage IgG and IgA antibodies that bound to the surface of N. gonorrhoeae cells, as shown by indirect fluorescent analysis and flow cytometry. The elicited sera was able to bind to several phage proteins. The sera also had bactericidal activity. These data demonstrate that N. gonorrhoeae filamentous phage can induce antibodies with anti-gonococcal activity and that phage proteins may be a candidate for vaccine development.

  15. Log reduction of multidrug-resistant Gram-negative bacteria by the neutrophil-derived recombinant bactericidal/permeability-increasing protein.

    Science.gov (United States)

    Weitz, Andrea; Spotnitz, Russell; Collins, Jennifer; Ovadia, Steven; Iovine, Nicole M

    2013-12-01

    Multidrug-resistant (MDR) Gram-negative bacterial infections are a serious and ever-increasing threat for which limited therapeutic options exist. The bactericidal/permeability-increasing protein (BPI) is a cationic, neutrophil-derived, lipopolysaccharide (LPS)-binding protein that binds to Gram-negative bacteria (GNB) and LPS via its lipid A region. A recombinant fragment, rBPI-21, was studied extensively in clinical trials for meningococcal disease in the 1990s and exhibited no significant safety issues. In this report, a dose-dependent 1-2 log reduction of MDR Pseudomonas and Acinetobacter after 1h incubation with rBPI-21 using clinically achievable doses is described. Given the dearth of novel antimicrobials expected to emerge from the pharmaceutical pipeline in the near future, exploration of rBPI-21 to combat MDR GNB is now warranted.

  16. [In vitro evaluation of bactericidal activity of an over-heated saturated dry atomized steam electro-medical device on inert contaminated surfaces].

    Science.gov (United States)

    Storni, E; Donati, M E; Naldi, S; Pederzoli, A; Maso, A

    2011-01-01

    Surface disinfection together with cleaning practises and aseptic procedures are established measures for effective prevention of infectious diseases reducing infection risks. In this study, we evaluated the bactericidal effectiveness in vitro of the electro-medical device Sani System, an over-heated saturated dry-steam disinfection system, against predetermined bacterial load dried on inert surfaces. In particular we have tested different materials, representative of operating rooms furnishing and walls commonly used in healthcare setting, with Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii. As a result of treatment, the mean bacterial load on all the test surfaces was reduced by a factor of 102 in the contact plate experimental study and by a factor of 10 in the total bioburden experimental study. The Sani System Polti proved to be efficacious in killing 100% of the bacteria in all experimental conditions, therefore it could help to reduce the risk of spreading nosocomial infections in healthcare facilities.

  17. Children with Haemophilus influenzae type b (Hib) vaccine failure have long-term bactericidal antibodies against virulent Hib strains with multiple capsular loci.

    Science.gov (United States)

    Townsend-Payne, Kelly; Ladhani, Shamez N; Findlow, Helen; Slack, Mary; Borrow, Ray

    2016-07-25

    Children who develop invasive Haemophilus influenzae serotype b (Hib) disease after immunisation with a highly-effective conjugate vaccine are more likely to have been infected with Hib strains possessing multiple copies of the capsulation locus. Using a recently-validated serum bactericidal antibody (SBA) assay, we tested convalescent sera from 127 Hib vaccine failure cases against clinical Hib strains expressing 1-5 copies of the capsulation locus. SBA titres correlated weakly with anti-capsular IgG antibody concentrations and there was no association between SBA geometric mean titres and number of capsulation locus copies. After infection, children with Hib vaccine failure were equally protected against Hib strains with 1-5 copies of the capsulation locus.

  18. Effects of assisted magnetic field to an atmospheric-pressure plasma jet on radical generation at the plasma-surface interface and bactericidal function

    Science.gov (United States)

    Liu, Chih-Tung; Kumakura, Takumi; Ishikawa, Kenji; Hashizume, Hiroshi; Takeda, Keigo; Ito, Masafumi; Hori, Masaru; Wu, Jong-Shinn

    2016-12-01

    A configuration of magnetic-assisted-plasma (MAP) on helium-based atmospheric-pressure plasma jet (APPJ) with an axial magnetic-field of 0.587 T is proposed, which provides good ability for killing bacteria Escherichia coli on the agar surface. Optically, we confirmed that the MAP increased approximately 2.4 times in the electron density estimated by the Stark broadening of H β line emission, and approximately 1.5 times enhancement of atomic oxygen concentration measured by vacuum ultraviolet absorption spectroscopy (VUVAS). Moreover, the generation of hydroxyl radical in the water increased 1.5 times, confirmed by the spin-trapping electron spin-resonance technique. In addition, the bactericidal experiments demonstrated 2.4 times higher for E. coli by the MAP treatment. The MAP configuration is proposed to be highly useful for future bio-medical applications by enhancing the radical generation at the plasma/substrate interface region.

  19. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti–Ag and Nb–Ag thin films

    Energy Technology Data Exchange (ETDEWEB)

    Wojcieszak, D., E-mail: damian.wojcieszak@pwr.edu.pl [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Mazur, M.; Kaczmarek, D. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Mazur, P. [Institute of Experimental Physics, University of Wrocław, Max Born 9, 50-204 Wrocław (Poland); Szponar, B. [Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53–114 Wrocław (Poland); Domaradzki, J. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Kepinski, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland)

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti–Ag and Nb–Ag thin films have been carried out. Ti–Ag and Nb–Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti–Ag and Nb–Ag thin films were nanocrystalline. In the case of Ag–Ti film presence of AgTi{sub 3} and Ag phases was identified, while in the structure of Nb–Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11 nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb–Ag thin films was covered with Ag-agglomerates, while Ti–Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2 h. - Highlights: • Surface and biological properties of Ti–Ag and Nb–Ag thin films were examined. • Ag content was related to sputtering yields and nucleation of Ti and Nb. • For Nb–Ag film the agglomeration of silver at the surface was observed. • Composition and surface topography had an impact on antimicrobial properties. • Fine-grained surface was important in Ag ions release process.

  20. Preparation of Ag/TiO2/SiO2 films via photo-assisted deposition and adsorptive self-assembly for catalytic bactericidal application

    Science.gov (United States)

    Xi, Baojuan; Chu, Xiaona; Hu, Jiangyong; Bhatia, Charanjit Singh; Danner, Aaron James; Yang, Hyunsoo

    2014-08-01

    The deterioration of water supply quality due to the waterborne bacteria is an environmental problem requiring the urgent attention. Due to the excellent and synergic antimicrobial capability, Ag-loaded TiO2 photocatalyst emerges as a feasible measure to guard the water. In our work, Ag nanoparticles have been prepared by the photoassisted reduction of AgNO3 on the TiO2 film fabricated by solution-based adsorptive self-assembly approach. The role of surfactant on the growth rate and size controlling of particles is also studied. In this connection, different kinds of surfactants, such as PVP, Tween-20, Tween-40 and so on, are applied in the system to investigate the formation of Ag nanoparticles. The surface profile and elemental analysis of Ag/TiO2/SiO2 films are examined by scanning electron microscopy and attached energy-dispersive X-ray spectroscopy, respectively. In the anti-bacteria detection, Ag nanoparticles are found to enhance the bactericidal efficiency strongly comparing with the pure TiO2 film under the same condition. In addition, by comparison with Ag/TiO2/SiO2 film in the dark environment as the reference experiment, UV-visible light plays a vital role in the improved bactericidal behavior, demonstrating the more efficient charge separation induced by metal silver. Because of the versatility of the method, the present photoreductive route is also exploited for the synthesis of Au nanoparticles on TiO2/SiO2 films. The corresponding photocatalytical detection results demonstrate the loading of Au nanoparticles can improve the photodegradation efficiency of methyl orange assigned to the similar electron-trapping effect to silver.

  1. A putative amino acid ABC transporter substrate-binding protein, NMB1612, from Neisseria meningitidis, induces murine bactericidal antibodies against meningococci expressing heterologous NMB1612 proteins.

    Science.gov (United States)

    Hung, Miao-Chiu; Humbert, María Victoria; Laver, Jay R; Phillips, Renee; Heckels, John E; Christodoulides, Myron

    2015-08-26

    The nmb1612 (NEIS1533) gene encoding the ~27-kDa putative amino acid ATP-binding cassette (ABC) transporter, periplasmic substrate-binding protein from Neisseria meningitidis serogroup B (MenB) strain MC58 was cloned and expressed in Escherichia coli, and the purified recombinant (r)NMB1612 was used for animal immunization studies. Immunization of mice with rNMB1612 adsorbed to Al(OH)3 and in liposomes with and without MPLA, induced antiserum with bactericidal activity in an assay using baby rabbit complement, against the homologous strain MC58 (encoding protein representative of Allele 62) and killed heterologous strains encoding proteins of three other alleles (representative of Alleles 1, 64 and 68), with similar SBA titres. However, strain MC58 was not killed (titre protein was killed (median titres of 16-64 in the hSBA). Analysis of the NMB1612 amino acid sequences from 4351 meningococcal strains in the pubmlst.org/Neisseria database and a collection of 13 isolates from colonized individuals and from patients, showed that antibodies raised against rNMB1612 could potentially kill at least 72% of the MenB strains in the complete sequence database. For MenB disease occurring specifically in the UK from 2013 to 2015, >91% of the isolates causing disease in this recent period expressed NMB1612 protein encoded by Allele 1 and could be potentially killed by sera raised to the recombinant antigen in the current study. The NMB1612 protein was surface-accessible and expressed by different meningococcal strains. In summary, the properties of (i) NMB1612 protein conservation and expression, (ii) limited amino acid sequence variation between proteins encoded by different alleles, and (iii) the ability of a recombinant protein to induce cross-strain bactericidal antibodies, would all suggest a promising antigen for consideration for inclusion in new meningococcal vaccines.

  2. Citrate-capped silver nanoparticles showing good bactericidal effect against both planktonic and sessile bacteria and a low cytotoxicity to osteoblastic cells.

    Science.gov (United States)

    Flores, Constanza Y; Miñán, Alejandro G; Grillo, Claudia A; Salvarezza, Roberto C; Vericat, Carolina; Schilardi, Patricia L

    2013-04-24

    A common problem with implants is that bacteria can form biofilms on their surfaces, which can lead to infection and, eventually, to implant rejection. An interesting strategy to inhibit bacterial colonization is the immobilization of silver (Ag) species on the surface of the devices. The aim of this paper is to investigate the action of citrate-capped silver nanoparticles (AgNPs) on clinically relevant Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria in two different situations: (i) dispersed AgNPs (to assess the effect of AgNPs against planktonic bacteria) and (ii) adsorbed AgNPs on titanium (Ti) substrates, a material widely used for implants (to test their effect against sessile bacteria). In both cases, the number of surviving cells was quantified. The small amount of Ag on the surface of Ti has an antimicrobial effect similar to that of pure Ag surfaces. We have also investigated the capability of AgNPs to kill planktonic bacteria and their cytotoxic effect on UMR-106 osteoblastic cells. The minimum bactericidal concentration found for both strains is much lower than the AgNP concentration that leads to cytotoxicity to osteoblasts. Planktonic P. aeruginosa show a higher susceptibility to Ag than S. aureus, which can be caused by the different wall structures, while for sessile bacteria, similar results are obtained for both strains. This can be explained by the presence of extracellular polymeric substances in the early stages of P. aeruginosa biofilm formation. Our findings can be important to improving the performance of Ti-based implants because a good bactericidal action is obtained with very small quantities of Ag, which are not detrimental to the cells involved in the osseointegration process.

  3. Effect of Nano-TiO2 on Bactericidal Activity of Bamboo Flour/PVC Composites%纳米二氧化钛对竹粉/PVC抗菌性能的影响

    Institute of Scientific and Technical Information of China (English)

    万正龙; 蔡杰; 刘森; 熊汉国

    2011-01-01

    Bamboo flour/PVC composites with different content of nano-TiO2 were prepared, and the effect of nano-TiO2 0n the mechanical properties and bactericidal activity of the composites was investigated.The results show that nano-TiO2 can obviously improve the mechanical properties of the composites, and the composites show excellent bactericidal activity on the E.coli and S.aureus.The bactericidal activity of the composites is more than 90% when the content of nano-TiO2 is 1.2 %.When the content of nano-TiO2 is 1.6%, the bactericidal activity of the composites is more than 99%.The composites have good long-time bactericidal activity.%制备了添加不同纳米二氧化钛(TiO2)含量的竹粉/聚氯乙烯(PVC)复合材料,研究纳米TiO2对复合材料力学性能和抗菌性能白子影响,结果表明,纳米TiO2能显著提高复合材料的力学性能,且赋予材料对大肠杆菌和金黄色葡萄球菌很好的抗菌性能;当纳米TiO2质量分数为1.2%时,复合材料的抗菌率大于90%,抗菌效果显著;当纳米TiO2质量分数为1.6%时,复合材料的抗菌率均超过了99%,且复合材料具有良好的抗菌长效性.

  4. Efeito bactericida do gerador de alta frequência na cultura de Staphylococcus aureus Bactericidal effect of high frequency generator in Staphylococcus aureus culture

    Directory of Open Access Journals (Sweden)

    Andiara Martins

    2012-06-01

    Full Text Available O objetivo deste estudo foi verificar o efeito bactericida do gerador de alta frequência sobre a cultura de Staphylococcus aureus. Para isso, 36 placas de Petri inoculadas com Staphylococcus aureus foram divididas em 6 grupos, sendo 4 tratados (G5-15, G5-10, G3-15 e G3-10 e 2 controles (GC3 e GC5. O G5-15 e o G5-10 foram tratados 5 vezes por semana durante 15 e 10 minutos respectivamente, enquanto o G3-15 e o G3-10 foram tratados 3 vezes por semana durante 15 e 10 minutos respectivamente. No tratamento, foi utilizado o gerador de alta frequência na intensidade 10, técnica de faiscamento com eletrodo standard. Após o 15º dia de tratamento, foram realizadas repicagens para verificar se houve crescimento de novas culturas, observando-se que apenas o G5-15 mostrou-se eficaz quando comparado ao GC5 (p=0,0039. Assim, o gerador de alta frequência apresentou efeito bactericida diante de cultura de Staphylococcus aureus in vitro em uma frequência de 5 vezes por semana aplicado por 15 minutos diários.The purpose of this study was to check the bactericidal effect of the high frequency generator over the Staphylococcus aureus culture. A total of 36 Petri dishes inoculated with Staphylococcus aureus were divided into 6 groups, including 4 treated (G5-15, G5-10, G3-15 and G3-10 and 2 controls (GC3 e GC5. G5-15 and G5-10 were treated 5 times per week during 15 and 10 minutes, respectively, while G3-15 and G3-10 were treated 3 times per week during 15 and 10 minutes, respectively. In treatment, it was used the high frequency generator with intensity of 10, sparking technique with standard electrode. After the 15th day of treatment, there were performed transplanting, in order to check if there were growth of new cultures, and only G5-15 showed to be effective when compared to GC5 (p=0.0039. So, the high frequency generator had a bactericidal effect on Staphylococcus aureus in vitro culture at a frequency of 5 times per week and exposure time of 15

  5. Recombinant Protein Truncation Strategy for Inducing Bactericidal Antibodies to the Macrophage Infectivity Potentiator Protein of Neisseria meningitidis and Circumventing Potential Cross-Reactivity with Human FK506-Binding Proteins

    OpenAIRE

    Bielecka, Magdalena K.; Devos, Nathalie; Gilbert, Mélanie; Hung, Miao-Chiu; Weynants, Vincent; Heckels, John E.; Christodoulides, Myron

    2014-01-01

    A recombinant macrophage infectivity potentiator (rMIP) protein of Neisseria meningitidis induces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human protein...

  6. Effect of porcine reproductive and respiratory syndrome virus (PRRSV) (isolate ATCC VR-2385) infection on bactericidal activity of porcine pulmonary intravascular macrophages (PIMs): in vitro comparisons with pulmonary alveolar macrophages (PAMs).

    Science.gov (United States)

    Thanawongnuwech, R; Thacker, E L; Halbur, P G

    1997-11-01

    Porcine pulmonary intravascular macrophages (PIMs) were recovered by in situ pulmonary vascular perfusion with 0.025% collagenase in saline from six 8-week old, crossbred pigs. Pulmonary alveolar macrophages (PAMs) were recovered by bronchoalveolar lavage from the same pigs for comparisons in each assay. The macrophages were exposed to PRRSV (ATCC VR-2385) in vitro for 24 h and infection was confirmed by an indirect immunofluorescence test or transmission electron microscopy. Viral particles tended to accumulate in the vesicles of the Golgi apparatus or endoplasmic reticulum. Bactericidal function assays were performed on the recovered macrophages to determine the effects of the virus on macrophage functions. In vitro PRRSV infection reduced the bactericidal ability of PIMs from 68.3% to 56.4% (P PAMs from 69.3% to 61.0% (P > 0.1) at 24 h post-infection. The mean percentage of bacteria killed by macrophages after PRRSV infection was not significantly different among the treatment groups or between the treatment groups and non-infected controls based on colorimetric MTT bactericidal (Staphylococcus aureus) assay. PRRSV did not affect the ability of PIMs or PAMs to internalize opsonized 125I-iododeoxyuridine-labeled S. aureus (P > 0.05). PRRSV infection significantly decreased the production of superoxide anion (P PAMs. PRRSV reduced the myeloperoxidase-H2O2-halide product (P PAMs. The results suggest: (1) PIMs should be considered as an important replication site of PRRSV; (2) PRRSV may have a detrimental effect on both PIMs and PAMs; (3) loss of bactericidal function in PIMs may facilitate hematogenous bacterial infections.

  7. 循环水紫外杀菌效果评价及影响因素研究%Evaluation of bactericidal effects of UV on circulating water and the research on influencing factors

    Institute of Scientific and Technical Information of China (English)

    闫岩; 郦和生; 任志峰; 李博伟

    2012-01-01

    评价了紫外技术对循环水的杀菌效果、循环水水质对紫外杀菌效果的影响,并考察了运行参数如杀菌时间、紫外剂量对杀菌效果的影响.结果表明:紫外光对循环水中的3种细菌有较好的杀菌效果.当紫外照射时间为2s,紫外剂量为0.04 J/cm2,循环水中总铁<0.5 mg/L,浊度<10 mg/L时,可使循环水中的异养菌数<1×105 mL-1.%The bactericidal effects of UV technique on circulating water and the impact of circulating water quality on UV bactericidal effects are evaluated. The impact of operation data such as sterilization time, UV dosage on bactericidal effects are investigated. The results show that UV light has comparatively good bactericidal capacity for three kinds of bacteria in circulating water. When the UV irradiation time is 2 s,UV dosage 0.04 J/cm2, total iron in circulating water<0.5 mg/L,and turbidity<10 mg/L,the quantity of heterotrophic bacteria is less than 1×105 mL-1.

  8. Evaluation of the bactericidal effect of five products for surgical hand disinfection according to prEN 12054 and prEN 12791.

    Science.gov (United States)

    Marchetti, M G; Kampf, G; Finzi, G; Salvatorelli, G

    2003-05-01

    Surgical hand disinfection (with an alcohol-based hand rub) and surgical handwash (with an antiseptic-based liquid soap) are accepted measures to reduce the risk for surgical site infections. The new European Standards allow a comparison of their antimicrobial efficacy. The bactericidal activity of surgical hand rubs [Sterillium and Softaman, (active ingredient=alcohols)] and handwashes [Derman plus (triclosan), Hibiscrub (chlorhexidine) and Betadine (PVP-iodine)] was tested according to the prEN 12054 suspension test using Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus hirae, and to prEN 12791 for the effect on resident skin flora in comparison with 1-propanol, 60% (v/v). All five products achieved a reduction of test bacteria within 3 min of >10(5)-fold so fulfilling prEN 12054. However, only Hibiscrub, Sterillium and Softa Man met the requirements of prEN 12791, giving a mean reduction of resident micro-organisms (immediate and sustained effect) which was not significantly lower than the reference alcohol (P>0.1; Wilcoxon matched-pairs signed-rank test). Sterillium was significantly more effective than the reference alcohol (immediate and sustained affect). Products for surgical hand disinfection may have equal antimicrobial activity in suspension tests but show large differences under practical conditions. Healthcare workers should not rely on results from suspension tests when deciding on a product for surgical hand disinfection.

  9. DUF538 protein super family is predicted to be the potential homologue of bactericidal/permeability-increasing protein in plant system.

    Science.gov (United States)

    Gholizadeh, Ashraf; Kohnehrouz, Samira Baghban

    2013-03-01

    DUF538 protein super family includes a number of plant proteins that their role is not yet clear. These proteins have been frequently reported to be expressed in plants under various stressful stimuli such as bacteria and elicitors. In order to further understand about this protein family we utilized bioinformatics tools to analyze its structure in details. As a result, plants DUF538 was predicted to be the partial structural homologue of BPI (bactericidal/permeability increasing) proteins in mammalian innate immune system that provides the first line of defense against different pathogens including bacteria, fungi, viruses and parasites. Moreover, on the base of the experimental data, it was identified that exogenously applied purified fused product of Celosia DUF538 affects the bacterial growth more possibly similar to BPI through the binding to the bacterial membranes. In conclusion, as the first ever time report, we nominated DUF538 protein family as the potential structural and functional homologue of BPI protein in plants, providing a basis to study the novel functions of this protein family in the biological systems in the future.

  10. Eco-friendly synthesis of silver and gold nanoparticles with enhanced bactericidal activity and study of silver catalyzed reduction of 4-nitrophenol.

    Science.gov (United States)

    Naraginti, Saraschandra; Sivakumar, A

    2014-07-15

    The present study reports a simple and robust method for synthesis of silver and gold nanoparticles using Coleus forskohlii root extract as reducing and stabilizing agent. Stable silver nanoparticles (AgNPs) and gold nanopoarticles (AuNPs) were formed on treatment of an aqueous silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solutions with the root extract. The nanoparticles obtained were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). UV-Vis and TEM analysis indicate that with higher quantities of root extract, the interaction is enhanced leading to size reduction of spherical metal nanoparticles. XRD confirms face-centered cubic phase and the diffraction peaks can be attributed to (111), (200), (222) and (311) planes for these nanoparticles. These synthesized Ag and Au nanoparticles were found to exhibit excellent bactericidal activity against clinically isolated selected pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The synthesized AgNPs were also found to function as an efficient green catalyst in the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride, which was apparent from the periodical color change from bright yellow to colorless, after the addition of AgNPs.

  11. Preparation of bio-deep eutectic solvent triggered cephalopod shaped silver chloride-DNA hybrid material having antibacterial and bactericidal activity.

    Science.gov (United States)

    Bhatt, Jitkumar; Mondal, Dibyendu; Bhojani, Gopal; Chatterjee, Shruti; Prasad, Kamalesh

    2015-11-01

    2.5% w/w DNA (Salmon testes) was solubilized in a bio-deep eutectic solvent [(bio-DES), obtained by the complexation of choline chloride and ethylene glycol at 1:2 molar ratio] containing 1% w/w of silver chloride (AgCl) to yield a AgCl decorated DNA based hybrid material. Concentration dependent formation of AgCl crystals in the DES was observed and upon interaction with DNA it gave formation of a cephalopod shaped hybrid material. DNA was found to maintain its chemical and structural stability in the material. Further, AgCl microstructures were found to have orderly self assembled on the DNA helices indicating the electrostatic interaction between Ag(+) and phosphate side chain of DNA as a driving force for the formation of the material with ordered microstructural distribution of AgCl. Furthermore, the functionalized material exhibited excellent antibacterial and bactericidal activity against both Gram negative and Gram positive pathogenic bacteria.

  12. ZnO-Ag core shell nanocomposite formed by green method using essential oil of wild ginger and their bactericidal and cytotoxic effects

    Science.gov (United States)

    Azizi, Susan; Mohamad, Rosfarizan; Rahim, Raha Abdul; Moghaddam, Amin Boroumand; Moniri, Mona; Ariff, Arbakariya; Saad, Wan Zuhainis; Namvab, Farideh

    2016-10-01

    In this paper, a novel green method for fabrication of zinc oxide-silver (ZnO-Ag) core-shell nanocomposite using essential oil of ginger (EO-G) is reported. The EO-G played two significant roles in the synthesis process: it could act as a reaction media for the formation of ZnO and reduce Ag+ to Ag0. The bioformed ZnO-Ag nanocomposite was compared with pure biosynthesized ZnO-NPs and characterized by UV-vis spectroscopy, TEM, EDX, XRD and FTIR. The characterization results confirmed that Ag-NPs had been embedded in ZnO hexagonal nanoparticles. Six Gram positive and negative pathogens were used to investigate the antibacterial effects of these samples. Ag-doping improves the bactericidal activity of ZnO-NPs. In vitro cytotoxicity studies on Vero cells, a dose dependent toxicity with non-toxic effect of concentration below 100 μg/mL was shown for ZnO-Ag nanocomposite. The biosynthesized ZnO-Ag nanocomposites were found to be comparable to those obtained from the conventional methods using hazardous materials which can be an excellent alternative for the synthesis of ZnO-Ag using biomass.

  13. Bactericidal Mechanism of Bio-oil Obtained from Fast Pyrolysis of Pinus densiflora Against Two Foodborne Pathogens, Bacillus cereus and Listeria monocytogenes.

    Science.gov (United States)

    Patra, Jayanta Kumar; Hwang, Hyewon; Choi, Joon Weon; Baek, Kwang-Hyun

    2015-06-01

    Foodborne bacteria are the leading cause of food spoilage and other related diseases. In the present study, the antibacterial activity of bio-oil (BO) manufactured by fast pyrolysis of pinewood sawdust (Pinus densiflora Siebold and Zucc.) against two disease-causing foodborne pathogens (Bacillus cereus and Listeria monocytogenes) was evaluated. BO at a concentration of 1000 μg/disc was highly active against both B. cereus (10.0-10.6 mm-inhibition zone) and L. monocytogenes (10.6-12.0-mm inhibition zone). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values of BO were 500 and 1000 μg/mL, respectively, for both pathogens. At the MIC concentration, BO exhibited an inhibitory effect on the viability of the bacterial pathogens. The mechanism of action of BO revealed its strong impairing effect on the membrane integrity of bacterial cells, which was confirmed by a marked release of 260-nm absorbing material, leakage of electrolytes and K(+) ions, and reduced capacity for osmoregulation under high salt concentration. Scanning electron microscopy clearly showed morphological alteration of the cell membrane due to the effect of BO. Overall, the results of this study suggest that BO exerts effective antibacterial potential against foodborne pathogens and can therefore potentially be used in food processing and preservation.

  14. Stem Bark Extract and Fraction of Persea americana (Mill. Exhibits Bactericidal Activities against Strains of Bacillus cereus Associated with Food Poisoning

    Directory of Open Access Journals (Sweden)

    David A. Akinpelu

    2014-12-01

    Full Text Available The study investigates the in vitro antibacterial potentials of stem bark extracts of Persea americana on strains of Bacillus cereus implicated in food poisoning. The crude stem bark extracts and butanolic fraction at a concentration of 25 mg/mL and 10 mg/mL, respectively, exhibited antibacterial activities against test isolates. The zones of inhibition exhibited by the crude extract and the fraction ranged between 10 mm and 26 mm, while the minimum inhibitory concentration values ranged between 0.78 and 5.00 mg/mL. The minimum bactericidal concentrations ranged between 3.12 mg/mL–12.5 mg/mL and 1.25–10 mg/mL for the extract and the fraction, respectively. The butanolic fraction killed 91.49% of the test isolates at a concentration of 2× MIC after 60 min of contact time, while a 100% killing was achieved after the test bacterial cells were exposed to the butanolic fraction at a concentration of 3× MIC after 90 min contact time. Intracellular protein and potassium ion leaked out of the test bacterial cells when exposed to certain concentrations of the fraction; this is an indication of bacterial cell wall disruptions by the extract’s butanolic fraction and, thus, caused a biocidal effect on the cells, as evident in the killing rate test results.

  15. Stem bark extract and fraction of Persea americana (Mill.) exhibits bactericidal activities against strains of bacillus cereus associated with food poisoning.

    Science.gov (United States)

    Akinpelu, David A; Aiyegoro, Olayinka A; Akinpelu, Oluseun F; Okoh, Anthony I

    2014-12-30

    The study investigates the in vitro antibacterial potentials of stem bark extracts of Persea americana on strains of Bacillus cereus implicated in food poisoning. The crude stem bark extracts and butanolic fraction at a concentration of 25 mg/mL and 10 mg/mL, respectively, exhibited antibacterial activities against test isolates. The zones of inhibition exhibited by the crude extract and the fraction ranged between 10 mm and 26 mm, while the minimum inhibitory concentration values ranged between 0.78 and 5.00 mg/mL. The minimum bactericidal concentrations ranged between 3.12 mg/mL-12.5 mg/mL and 1.25-10 mg/mL for the extract and the fraction, respectively. The butanolic fraction killed 91.49% of the test isolates at a concentration of 2× MIC after 60 min of contact time, while a 100% killing was achieved after the test bacterial cells were exposed to the butanolic fraction at a concentration of 3× MIC after 90 min contact time. Intracellular protein and potassium ion leaked out of the test bacterial cells when exposed to certain concentrations of the fraction; this is an indication of bacterial cell wall disruptions by the extract's butanolic fraction and, thus, caused a biocidal effect on the cells, as evident in the killing rate test results.

  16. Aqueous and Organic Solvent-Extracts of Selected South African Medicinal Plants Possess Antimicrobial Activity against Drug-Resistant Strains of Helicobacter pylori: Inhibitory and Bactericidal Potential

    Directory of Open Access Journals (Sweden)

    Collise Njume

    2011-09-01

    Full Text Available The aim of this study was to identify sources of cheap starting materials for the synthesis of new drugs against Helicobacter pylori. Solvent-extracts of selected medicinal plants; Combretum molle, Sclerocarya birrea, Garcinia kola, Alepidea amatymbica and a single Strychnos species were investigated against 30 clinical strains of H. pylori alongside a reference control strain (NCTC 11638 using standard microbiological techniques. Metronidazole and amoxicillin were included in these experiments as positive control antibiotics. All the plants demonstrated anti-H. pylori activity with zone diameters of inhibition between 0 and 38 mm and 50% minimum inhibitory concentration (MIC50 values ranging from 0.06 to 5.0 mg/mL. MIC50 values for amoxicillin and metronidazole ranged from 0.001 to 0.63 mg/mL and 0.004 to 5.0 mg/mL respectively. The acetone extracts of C. molle and S. birrea exhibited a remarkable bactericidal activity against H. pylori killing more than 50% of the strains within 18 h at 4× MIC and complete elimination of the organisms within 24 h. Their antimicrobial activity was comparable to the control antibiotics. However, the activity of the ethanol extract of G. kola was lower than amoxicillin (P < 0.05 as opposed to metronidazole (P > 0.05. These results demonstrate that S. birrea, C. molle and G. kola may represent good sources of compounds with anti-H. pylori activity.

  17. Nitrogen gas flushing can be bactericidal: the temperature-dependent destiny of Bacillus weihenstephanensis KBAB4 under a pure N2 atmosphere.

    Science.gov (United States)

    Munsch-Alatossava, Patricia; Alatossava, Tapani

    2014-01-01

    Gram-negative Pseudomonas and Gram-positive Bacillus are the most common spoilage bacteria in raw and pasteurized milk, respectively. In previous studies, nitrogen (N2) gas flushing treatments of raw and pasteurized milk at cold chain-temperatures inhibited bacterial spoilage and highlighted different susceptibilities to the N2 treatment with the exclusion of certain bacterial types. Here, we investigated the effects of pure N2 gas flushing on representative strains of these genera grown in mono- or co-cultures at 15 and 25°C. Bacillus weihenstephanensis, a frequent inhabitant of fluid dairy products, is represented by the genome-sequenced KBAB4 strain. Among Pseudomonas, P. tolaasii LMG 2342(T) and strain C1, a raw milk psychrotroph, were selected. The N2 gas flushing treatment revealed: (1) temperature-dependent responses; (2) inhibition of the growth of both pseudomonads; (3) emergence of small colony variants (SCVs) for B. weihenstephanensis strain KBAB4 at 15°C induced by the N2 treatment or when grown in co-culture with Pseudomonas strains; (4) N2 gas flushing modulates (suppressed or stimulated) bacterial antagonistic reactions in co-cultures; (5) most importantly, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed that at 25°C the majority of the KBAB4 cells were killed by pure N2 gas flushing. This observation constitutes the first evidence that N2 gas flushing has bactericidal effects.

  18. Evaluation of the bactericidal characteristics of nano-copper oxide or functionalized zeolite coating for bio-corrosion control in concrete sewer pipes

    Energy Technology Data Exchange (ETDEWEB)

    Haile, T. [Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, Ont., N6A 5B8 (Canada); Materials Technology Laboratory Branch, Natural Resources Canada, 562 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)], E-mail: thaile@uwo.ca; Nakhla, G. [Department of Chemical and Biochemical Engineering, University of Western Ontario, 1151 Richmond Street, London, Ont., N6A 5B8 (Canada)], E-mail: gnakhla@eng.uwo.ca; Allouche, E. [Trenchless Technology Centre, Louisiana Tech University, 600 W. Arizona, Engr. Annex, P.O. Box 10348, Ruston, LA 71272 (United States)], E-mail: allouche@LaTech.edu; Vaidya, S. [Trenchless Technology Centre, Louisiana Tech University, 600 W. Arizona, Engr. Annex, P.O. Box 10348, Ruston, LA 71272 (United States)], E-mail: sva008@LaTech.edu

    2010-01-15

    The bactericidal characteristics of nano-copper oxide or functionalized zeolite coated concrete pipes against Acidithiobacillus thiooxidans were studied by measuring the temporal variation of bacterial dry cell weight measurement, cellular Adenosine Triphosphate production, as well as oxygen uptake rate of the aforementioned bacterium. Uncorroded (UC), severely corroded (SC), and moderately corroded (MC) concrete pipes were electrochemically coated with a nano-copper oxide, while another uncorroded concrete pipe was used to apply functionalized zeolite coating (Z2). Specimens were characterized by field emission-scanning electron microscopy, and optical microscopy. Oxygen uptake rate of the bacterium was the highest in UC followed by the MC. Oxygen uptake rate and cellular Adenosine Triphosphate decreased progressively in Z2 and SC throughout the duration of the experiment due to decline in live bacterial cell. The maximum bacterial specific growth rate was 1.1 x 10{sup -2} day{sup -1} for both UC and MC, with a decay rates varying from 1.4 x 10{sup -2} to 2.6 x 10{sup -2} day{sup -1}. The minimum concentration limits for the inhibition of the bacterium in the nano-copper oxide coated concrete pipes ranged from 2.3 mg to 2.6 mg Cu per mg dry cell weight.

  19. [The interconnection between cytokines and the factors of bactericidal action of neutrophiles in patients operated on under the conditions of cardiopulmonary bypass].

    Science.gov (United States)

    Novitskiĭ, V V; Chumakova, S P; Shipulin, V M; Urazova, O I; Evtushenko, O M; Perevozchikova, T V; Suslova, T E; Emel'ianova, T V

    2006-01-01

    The use of cardiopulmonary bypass (CPB) is associated with the development of a system inflammatory response. The subjects of the study were 48 patients with coronary heart disease (CHD), operated on under the condition of CPB. The following parameters were measured: the content of cation proteins and active oxygen forms in neutrophiles, the digesting capacity of these cells, and the serum levels of interleukins (IL)-1beta, 1ra, -4, -6, -8, and tumor necrosis factor-alpha (TNF-alpha). The measurements were made before performing coronary bypass surgery, and also 6 and 24 hours after surgery. The results showed that the levels of cytokines and the bactericidal activity of neutrophiles were elevated in CHD patients before surgery. The changes after surgery included an increased macrophageal digesting capacity with switching to oxygen-independent mechanisms, as well as increased levels of TNF-alpha, IL-1ra, and IL-1ra:IL-1beta. The changes were more prominent 6 hours after surgery. Oxygen-dependent killing was controlled mostly by IL-6 during the pre-operative period, and by this plus TNF-alpha 24 hours after surgery. The content of cation proteins in neutrophiles before surgery correlated with the concentrations of TNF-alpha and IL-8. These interconnections weakened 6 hours after surgery and became stronger 24 hours after it.

  20. Phytic Acid and Sodium Chloride Show Marked Synergistic Bactericidal Effects against Nonadapted and Acid-Adapted Escherichia coli O157:H7 Strains.

    Science.gov (United States)

    Kim, Nam Hee; Rhee, Min Suk

    2015-12-04

    The synergistic antimicrobial effects of phytic acid (PA), a natural extract from rice bran, plus sodium chloride against Escherichia coli O157:H7 were examined. Exposure to NaCl alone at concentrations up to 36% (wt/wt) for 5 min did not reduce bacterial populations. The bactericidal effects of PA alone were much greater than those of other organic acids (acetic, citric, lactic, and malic acids) under the same experimental conditions (P acid-adapted cells, reducing their numbers to unrecoverable levels (>7-log CFU/ml reduction). Flow cytometry confirmed that PA disrupted the cell membrane to a greater extent than did other organic acids, although the cells remained viable. The combination of PA and NaCl induced complete disintegration of the cell membrane. By comparison, none of the other organic acids acted synergistically with NaCl, and neither did NaCl-HCl solutions at the same pH values as the test solutions of PA plus NaCl. These results suggest that PA has great potential as an effective bacterial membrane-permeabilizing agent, and we show that the combination is a promising alternative to conventional chemical disinfectants. These findings provide new insight into the utility of natural compounds as novel antimicrobial agents and increase our understanding of the mechanisms underlying the antibacterial activity of PA.

  1. The enhanced photocatalytic and bactericidal activities of carbon microsphere-assisted solvothermally synthesized cocoon-shaped Sn(4+)-doped ZnO nanoparticles.

    Science.gov (United States)

    Karunakaran, Chockalingam; SakthiRaadha, SakthiDasan; Gomathisankar, Paramasivan; Vinayagamoorthy, Pazhamalai

    2013-10-14

    Cocoon-shaped Sn(4+)-doped ZnO nanoparticles have been synthesized by a solvothermal method using carbon microspheres as a template. The optimum doping level for photocatalysis is 3% (g. atom). Powder X-ray diffractograms show that the ZnO has a primitive hexagonal crystal structure and that doping ZnO with Sn(4+) increases the unit cell lengths and the Zn-O bond lengths. Larger crystal growth along the c-axis is also observed. The measured size of the cocoon-shaped Sn(4+)-doped ZnO nanoparticles is larger than the mean crystallite size. Solid state impedance spectroscopy studies reveal that Sn(4+)-doping increases the charge transfer resistance. Doping does not significantly modify the optical band gap, but does suppress green emission. A decrease in the number of crystal defects due to oxygen vacancies is likely to be a reason for the enhanced photocatalytic properties of the cocoon-shaped Sn(4+)-doped ZnO nanoparticles. Doping ZnO with Sn(4+) enhances the bactericidal activity as well.

  2. Eco-friendly synthesis of silver and gold nanoparticles with enhanced bactericidal activity and study of silver catalyzed reduction of 4-nitrophenol

    Science.gov (United States)

    Naraginti, Saraschandra; Sivakumar, A.

    2014-07-01

    The present study reports a simple and robust method for synthesis of silver and gold nanoparticles using Coleus forskohlii root extract as reducing and stabilizing agent. Stable silver nanoparticles (AgNPs) and gold nanopoarticles (AuNPs) were formed on treatment of an aqueous silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solutions with the root extract. The nanoparticles obtained were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). UV-Vis and TEM analysis indicate that with higher quantities of root extract, the interaction is enhanced leading to size reduction of spherical metal nanoparticles. XRD confirms face-centered cubic phase and the diffraction peaks can be attributed to (1 1 1), (2 0 0), (2 2 2) and (3 1 1) planes for these nanoparticles. These synthesized Ag and Au nanoparticles were found to exhibit excellent bactericidal activity against clinically isolated selected pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The synthesized AgNPs were also found to function as an efficient green catalyst in the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride, which was apparent from the periodical color change from bright yellow to colorless, after the addition of AgNPs.

  3. Azithromycin Synergizes with Cationic Antimicrobial Peptides to Exert Bactericidal and Therapeutic Activity Against Highly Multidrug-Resistant Gram-Negative Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Leo Lin

    2015-07-01

    Full Text Available Antibiotic resistance poses an increasingly grave threat to the public health. Of pressing concern, rapid spread of carbapenem-resistance among multidrug-resistant (MDR Gram-negative rods (GNR is associated with few treatment options and high mortality rates. Current antibiotic susceptibility testing guiding patient management is performed in a standardized manner, identifying minimum inhibitory concentrations (MIC in bacteriologic media, but ignoring host immune factors. Lacking activity in standard MIC testing, azithromycin (AZM, the most commonly prescribed antibiotic in the U.S., is never recommended for MDR GNR infection. Here we report a potent bactericidal action of AZM against MDR carbapenem-resistant isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. This pharmaceutical activity is associated with enhanced AZM cell penetration in eukaryotic tissue culture media and striking multi-log-fold synergies with host cathelicidin antimicrobial peptide LL-37 or the last line antibiotic colistin. Finally, AZM monotherapy exerts clear therapeutic effects in murine models of MDR GNR infection. Our results suggest that AZM, currently ignored as a treatment option, could benefit patients with MDR GNR infections, especially in combination with colistin.

  4. Pharmacokinetics of a recombinant modified amino terminal fragment of bactericidal/permeability-increasing protein (rBPI21) in healthy volunteers.

    Science.gov (United States)

    Bauer, R J; Wedel, N; Havrilla, N; White, M; Cohen, A; Carroll, S F

    1999-11-01

    Phase I pharmacokinetic and safety studies were conducted in healthy volunteers with rBPI21, a recombinant protein derived from the amino terminal domain of human bactericidal/permeability-increasing protein. rBPI21 was administered as a 30-minute infusion at doses of 0.25 to 4 mg/kg or as a 24- to 48-hour infusion at doses of 2 to 8 mg/kg. For the 30-minute infusions, the clearance of rBPI21 decreased with increasing dose from 8.4 mL/min/kg at 0.25 mg/kg to 3.3 mL/min/kg at 4 mg/kg. For rBPI21 infused over 24 to 48 hours the clearance was 10 to 11 mL/min/kg. The concentration-time profile of rBPI21 was well described by a three-compartmental model with parallel first-order and Michaelis-Menten (saturable) elimination. This model for the clearance of rBPI21 has been useful in estimating starting doses for therapeutic clinical trials.

  5. Exploring a new phenomenon in the bactericidal response of TiO{sub 2} thin films by Fe doping: Exerting the antimicrobial activity even after stoppage of illumination

    Energy Technology Data Exchange (ETDEWEB)

    Naghibi, Sanaz, E-mail: naghibi@iaush.ac.ir [Department of Metallurgy and Materials Engineering, Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Vahed, Shohreh, E-mail: sh_vahed@iaush.ac.ir [Department of Food Science, Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Torabi, Omid, E-mail: omid_trb@yahoo.com [Department of Materials Engineering, Najafabad Branch, Advanced Materials Research Center, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Jamshidi, Amin, E-mail: amin_jam_g@yahoo.com [Department of Materials Engineering, Najafabad Branch, Advanced Materials Research Center, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Golabgir, Mohammad Hossein, E-mail: m.hosseingolabgir@yahoo.com [Department of Materials Engineering, Najafabad Branch, Advanced Materials Research Center, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

    2015-02-01

    Graphical abstract: - Highlights: • Highly uniform Fe–TiO{sub 2} thin films were deposited on glass using sol–gel hot-dipping technique. • The photocatalytic properties were studied upon UV and visible irradiation. • By Fe doping into TiO{sub 2} structure, its microbial performance was prolonged even after stopping the illumination. • Due to Fe doping, the significant improvement in bactericidal coating was evident. - Abstract: Antibacterial properties of Fe-doped TiO{sub 2} thin films prepared on glass by the sol–gel hot-dipping technique were studied. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, scanning probe microscopy and X-ray photoelectron spectroscopy. The photocatalytic activities were evaluated by measuring the decomposition rate of methylene blue under ultra violet and visible light. The antibacterial properties of the coatings were investigated against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisia and Aspergillus niger. The principle of incubation methods was also discussed. The results indicated that Fe doping of thin films eventuated in high antibacterial properties under visible light and this performance remained even after stoppage of illumination. This article tries to provide some explanation for this fact.

  6. Intranasal immunization of mice with recombinant Streptococcus gordonii expressing NadA of Neisseria meningitidis induces systemic bactericidal antibodies and local IgA.

    Science.gov (United States)

    Ciabattini, Annalisa; Giomarelli, Barbara; Parigi, Riccardo; Chiavolini, Damiana; Pettini, Elena; Aricò, Beatrice; Giuliani, Marzia M; Santini, Laura; Medaglini, Donata; Pozzi, Gianni

    2008-08-05

    NadA and NhhA, two surface proteins of serogroup B Neisseria meningitidis identified as candidate vaccine antigens, were expressed on the surface of the human oral commensal bacterium Streptococcus gordonii. Recombinant strains were used to immunize BALB/c mice by the intranasal route and the local and systemic immune response was assessed. Mice were inoculated with recombinant bacteria administered alone or with LTR72, a partially inactivated mutant of Escherichia coli heat-labile enterotoxin, as a mucosal adjuvant. Intranasal immunization with live bacteria expressing NadA induced a significant serum antibody response, with a prevalence of the IgG2a subclass, bactericidal activity in the sera of 71% of animals, and a NadA-specific IgA response in nasal and bronchoalveolar lavages. A formalin-inactivated recombinant strain of S. gordonii expressing NadA was also administered intranasally, inducing a systemic and mucosal humoral response comparable to that of live bacteria. The administration of recombinant bacteria with the mucosal adjuvant LTR72 stimulated a stronger systemic antibody response, protective in 85% of sera, while did not increase the local IgA response. Recombinant S. gordonii expressing NhhA induced a systemic but not mucosal antibody response. These data support the role of NadA as vaccine candidate against serogroup B meningococci, and the use of S. gordonii as vector for intranasal vaccination.

  7. Facile synthesis of gold nanoparticles on propylamine functionalized SBA-15 and effect of surface functionality of its enhanced bactericidal activity against gram positive bacteria

    Science.gov (United States)

    Bhuyan, Diganta; Gogoi, Animesh; Saikia, Mrinal; Saikia, Ratul; Saikia, Lakshi

    2015-07-01

    The facile synthesis of an SBA-15-pr-+NH3.Au0 nano-hybrid material by spontaneous autoreduction of aqueous chloroaurate anions on propylamine functionalized SBA-15 was successfully demonstrated. The as-synthesized SBA-15-pr-+NH3.Au0 nano-hybrid material was well characterized using low and wide angle x-ray diffraction (XRD), N2 adsorption-desorption isotherms, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), x-ray photoelectron spectroscopy (XPS), UV-Visible spectroscopy and atomic absorption spectroscopy (AAS). The activity of the nano-hybrid material as a potent bactericidal agent was successfully tested against Gram positive/negative bacteria viz. Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The colony killing percentage of Gram positive bacteria was found to be higher than Gram negative bacteria due to the stronger electrostatic interaction between the positively-charged amine functionality of SBA-15 and the negatively charged functionality of the bacterial cell wall.

  8. Shape-dependent bactericidal activity of TiO2 for the killing of Gram-negative bacteria Agrobacterium tumefaciens under UV torch irradiation.

    Science.gov (United States)

    Aminedi, Raghavendra; Wadhwa, Gunveen; Das, Niranjan; Pal, Bonamali

    2013-09-01

    This paper demonstrated the relative bactericidal activity of photoirradiated (6W-UV Torch, λ > 340 nm and intensity = 0.64 mW/cm(2)) P25-TiO2 nanoparticles, nanorods, and nanotubes for the killing of Gram-negative bacterium Agrobacterium tumefaciens LBA4404 for the first time. TiO2 nanorod (anatase) with length of 70-100 nm and diameter of 10-12 nm, and TiO2 nanotube with length of 90-110 nm and diameter of 9-11 nm were prepared from P-25 Degussa TiO2 (size, 30-50 nm) by hydrothermal method and compared their biocidal activity both in aqueous slurry and thin films. The mode of bacterial cell decomposition was analyzed through transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR), and K(+) ion leakage. The antimicrobial activity of photoirradiated TiO2 of different shapes was found to be in the order P25-TiO2 > nanorod > nanotube which is reverse to their specific surface area as 54 TiO2 nanoparticles is not due to surface area as their crystal structure and surface morphology are entirely different. TiO2 thin films always exhibited less photoactivity as compared to its aqueous suspension under similar conditions of cell viability test. The changes in the bacterial surface morphology by UV-irradiated P25-TiO2 nanoparticles was examined by TEM, oxidative degradation of cell components such as proteins, carbohydrates, phospholipids, nucleic acids by FT-IR spectral analysis, and K(+) ion leakage (2.5 ppm as compared to 0.4 ppm for control culture) as a measure of loss in cell membrane permeability.

  9. On the use of capillary cytometry for assessing the bactericidal effect of TiO2. Identification and involvement of reactive oxygen species.

    Science.gov (United States)

    Carré, Gaelle; Benhamida, Dounia; Peluso, Jean; Muller, Christian D; Lett, Marie-Claire; Gies, Jean-Pierre; Keller, Valérie; Keller, Nicolas; André, Philippe

    2013-04-01

    The photocatalytic antimicrobial properties of TiO2 were studied on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa bacterial strains taken as model strains for pathogenic species mainly implied in nosocomial infections. Capillary cytometry, coupled to a double-staining method for visualizing membrane integrity as a cell viability indicator, was highlighted as a rapid, easy-to-use, and automated numeration technique for quantitative and reproducible determination of cellular viability and thus, was able to give an accurate evaluation of the bactericidal effect of UV-A photocatalysis. Cytometry also enabled the study of TiO2-bacteria interactions and aggregation in the dark as well as TiO2 cytotoxicity. Compared with the traditional agar plate cultivation method, a significatively weaker reduction in cell viability was recorded by cytometry whatever the bacteria, TiO2 concentration, and duration of the photocatalytic treatment. The mismatch between both numeration methods was attributed to: (i) the presence of mixed bacteria-TiO2 aggregates that could interfere with bacteria measurement on plates, (ii) prolonged contact of the bacteria with TiO2 during incubation, which could cause additional cytotoxic damage to the bacterial wall, and (iii) the counting of viable but non-culturable bacteria as live bacteria in cytometry, whereas they cannot grow on solid media. A more pronounced difference was observed for P. aeruginosa and S. aureus bacteria, for which 2.9 and 1.9 log10 survival reduction overestimations were measured by plate counting, respectively. Using chemiluminescence, full restoration of cell viability by controlled addition of the O2˙(-) scavenger superoxide dismutase enzyme suggests that O2˙(-) acts, in our conditions, as the main reactive oxygen species responsible for the photocatalytic attack towards the targeted bacteria.

  10. A Novel Small-Molecule Inhibitor of the Mycobacterium tuberculosis Demethylmenaquinone Methyltransferase MenG Is Bactericidal to Both Growing and Nutritionally Deprived Persister Cells

    Science.gov (United States)

    Sukheja, Paridhi; Kumar, Pradeep; Mittal, Nisha; Li, Shao-Gang; Singleton, Eric; Russo, Riccardo; Perryman, Alexander L.; Shrestha, Riju; Awasthi, Divya; Husain, Seema; Soteropoulos, Patricia; Brukh, Roman; Connell, Nancy; Freundlich, Joel S.

    2017-01-01

    ABSTRACT Active tuberculosis (TB) and latent Mycobacterium tuberculosis infection both require lengthy treatments to achieve durable cures. This problem has partly been attributable to the existence of nonreplicating M. tuberculosis “persisters” that are difficult to kill using conventional anti-TB treatments. Compounds that target the respiratory pathway have the potential to kill both replicating and persistent M. tuberculosis and shorten TB treatment, as this pathway is essential in both metabolic states. We developed a novel respiratory pathway-specific whole-cell screen to identify new respiration inhibitors. This screen identified the biphenyl amide GSK1733953A (DG70) as a likely respiration inhibitor. DG70 inhibited both clinical drug-susceptible and drug-resistant M. tuberculosis strains. Whole-genome sequencing of DG70-resistant colonies identified mutations in menG (rv0558), which is responsible for the final step in menaquinone biosynthesis and required for respiration. Overexpression of menG from wild-type and DG70-resistant isolates increased the DG70 MIC by 4× and 8× to 30×, respectively. Radiolabeling and high-resolution mass spectrometry studies confirmed that DG70 inhibited the final step in menaquinone biosynthesis. DG70 also inhibited oxygen utilization and ATP biosynthesis, which was reversed by external menaquinone supplementation. DG70 was bactericidal in actively replicating cultures and in a nutritionally deprived persistence model. DG70 was synergistic with the first-line TB drugs isoniazid, rifampin, and the respiratory inhibitor bedaquiline. The combination of DG70 and isoniazid completely sterilized cultures in the persistence model by day 10. These results suggest that MenG is a good therapeutic target and that compounds targeting MenG along with standard TB therapy have the potential to shorten TB treatment duration. PMID:28196957

  11. Identification and expression analysis on bactericidal permeability-increasing protein (BPI)/lipopolysaccharide-binding protein (LBP) of ark shell, Scapharca broughtonii.

    Science.gov (United States)

    Mao, Yuze; Zhou, Chunya; Zhu, Ling; Huang, Yao; Yan, Tingru; Fang, Jianguang; Zhu, Wei

    2013-09-01

    Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are the numbers of the lipid transfer protein/lipopolysaccharide-binding protein family and play crucial roles in the innate immune response to Gram-negative bacteria. A novel Sb-BPI/LBP1 from ark shell Scapharca broughtonii was isolated by expressed sequence tag (EST) and RACE techniques. The Sb-BPI/LBP1 cDNA encoded a polypeptide of 484 amino acids with a putative signal peptide of 21 amino acid residues and a mature protein of 463 amino acids. The deduced amino acid sequence of Sb-BPI/LBP1 contained an N-terminal BPI/LBP/CETP domain BPI1 with three functional regions that display LPS-binding activity, and a C-terminal BPI/LBP/CETP domain BPI2. In structure and sequence, Sb-BPI/LBP1 showed highly similar to those of the BPI/LBPs from invertebrate and non-mammalian vertebrate, the LBPs and BPIs from mammal. By quantitative real-time RT-PCR, Sb-BPI/LBP1 transcripts could be detected in all normal tested tissues, including hepatopancreas, adductor muscle, mantle margin, heart, gonad, gill and hemocytes, and was universally up-regulatable at 24 h post LPS challenge. The mRNA expression of Sb-BPI/LBP1 in hemocytes was the most sensitive to LPS challenge, significantly up-regulated at 12 h post LPS challenge and peaked at 24 h (16.76-fold, P ark shell S. broughtonii.

  12. Biological and bactericidal properties of Ag-doped bioactive glass in a natural extracellular matrix hydrogel with potential application in dentistry

    Directory of Open Access Journals (Sweden)

    Y-Y Wang

    2015-06-01

    Full Text Available The aim of this study was the fabrication and evaluation of a novel bioactive and bactericidal material, which could have applications in dentistry by supporting tissue regeneration and killing oral bacteria. Our hypothesis was that a new scaffold for pulp-dentin tissue engineering with enhanced antibacterial activity could be obtained by associating extracellular matrix derived from porcine bladder with an antibacterial bioactive glass. Our study combines in vitro approaches and ectopic implantation in scid mice. The novel material was fabricated by incorporating a sol-gel derived silver (Ag-doped bioactive glass (BG in a natural extracellular matrix (ECM hydrogel in ratio 1:1 in weight % (Ag-BG/ECM. The biological properties of the Ag-BG/ECM were evaluated in culture with dental pulp stem cells (DPSCs. In particular, cell proliferation, cell apoptosis, stem cells markers profile, and cell differentiation potential were studied. Furthermore, the antibacterial activity against Streptococcus mutans and Lactobacillus casei was measured. Moreover, the capability of the material to enhance pulp/dentin regeneration in vivo was also evaluated. Our data show that Ag-BG/ECM significantly enhances DPSCs’ proliferation, it does not affect cell morphology and stem cells markers profile, protects cells from apoptosis, and enhances in vitro cell differentiation and mineralisation potential as well as in vivo dentin formation. Furthermore, Ag-BG/ECM strongly inhibits S. mutans and L. casei growth suggesting that the new material has also anti-bacterial properties. This study provides foundation for future clinical applications in dentistry. It could potentially advance the currently available options of dental regenerative materials.

  13. Antimycobacterial natural products from Moroccan medicinal plants:Chemical composition, bacteriostatic and bactericidal profile of Thymus satureioides and Mentha pulegium essential oils

    Institute of Scientific and Technical Information of China (English)

    Marwa Chraibi; Abdellah Farah; Sara Lebrazi; Oumaima El Amine; Mohammed Iraqui Houssaini; Kawtar Fikri-Benbrahim

    2016-01-01

    Objective: To evaluate the susceptibility of Mycobacterium aurum and Mycobacterium smegmatis in vitro to the essential oils obtained from two medicinal plants: Thymus satureioides (T. satureioides) and Mentha pulegium (M. pulegium), and to study their chemical composition. Methods: The aerial parts of T. satureioides and M. pulegium (leaves and stems) were hydro-distillated using a Clevenger-type apparatus and essential oils were analyzed and identified by gas chromatography-mass spectrometry. Antimycobacterial screening of essential oils was performed on the basis of the inhibition zone diameter by disc diffusion method against two mycobacterial strains whereas the minimal inhibitory concentration and minimal bactericidal concentration were determined by using the micro-dilution method. Results: Chemical analysis of their aerial part's essential oils gave as major compounds, borneol (34.26%), carvacrol (31.21%) and thymol (3.71%) for T. satureioides and R(+)-pulegone (75.48%), carvone (6.66%) and dihydrocarvone (4.64%) for M. pulegium. Thereafter their antimycobacterial effect evaluation, using the micro-dilution method, indicated that minimal inhibitory concentration values of T. satureioides essential oil ranged from 0.062%to 0.015%(v/v) and from 0.125%to 0.031%(v/v) for M. pulegium respectively against Mycobacterium aurum and Mycobacterium smegmatis. Conclusions: It is clearly evident from the results obtained that the Moroccan medicinal plants have great potential to be used as anti-tuberculosis agents. These findings may help scientists to undertake several research projects to discover useful natural product as new anti-tuberculosis drug.

  14. Biological and bactericidal properties of Ag-doped bioactive glass in a natural extracellular matrix hydrogel with potential application in dentistry.

    Science.gov (United States)

    Wang, Y-Y; Chatzistavrou, X; Faulk, D; Badylak, S; Zheng, L; Papagerakis, S; Ge, L; Liu, H; Papagerakis, P

    2015-06-20

    The aim of this study was the fabrication and evaluation of a novel bioactive and bactericidal material, which could have applications in dentistry by supporting tissue regeneration and killing oral bacteria. Our hypothesis was that a new scaffold for pulp-dentin tissue engineering with enhanced antibacterial activity could be obtained by associating extracellular matrix derived from porcine bladder with an antibacterial bioactive glass. Our study combines in vitro approaches and ectopic implantation in scid mice. The novel material was fabricated by incorporating a sol-gel derived silver (Ag)-doped bioactive glass (BG) in a natural extracellular matrix (ECM) hydrogel in ratio 1:1 in weight % (Ag-BG/ECM). The biological properties of the Ag-BG/ECM were evaluated in culture with dental pulp stem cells (DPSCs). In particular, cell proliferation, cell apoptosis, stem cells markers profile, and cell differentiation potential were studied. Furthermore, the antibacterial activity against Streptococcus mutans and Lactobacillus casei was measured. Moreover, the capability of the material to enhance pulp/dentin regeneration in vivo was also evaluated. Our data show that Ag-BG/ECM significantly enhances DPSCs' proliferation, it does not affect cell morphology and stem cells markers profile, protects cells from apoptosis, and enhances in vitro cell differentiation and mineralisation potential as well as in vivo dentin formation. Furthermore, Ag-BG/ECM strongly inhibits S. mutans and L. casei growth suggesting that the new material has also anti-bacterial properties. This study provides foundation for future clinical applications in dentistry. It could potentially advance the currently available options of dental regenerative materials.

  15. High loading of graphene oxide/multi-walled carbon nanotubes into PDLLA: A route towards the design of osteoconductive, bactericidal and non-immunogenic 3D porous scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, Hudson [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil); Laboratory of Energy Storage & Supply - ES& S, Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, CEP: 12.244-000, Sao Paulo (Brazil); Rodrigues, Bruno Vinícius Manzolli [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil); Ribeiro Neto, Wilson Alves; Bretas, Rosario Elida Suman [Department of Materials Engineering, Federal University of Sao Carlos, Rodovia Washington Luis, km 235 – SP-310, Sao Carlos, Sao Paulo (Brazil); Da-Silva, Newton Soares [Laboratory of Cell Biology and Tissue, Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, CEP: 12244-000, Sao Paulo (Brazil); Marciano, Fernanda Roberta [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil); Oliveira Lobo, Anderson, E-mail: aolobo@pq.cnpq.br [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil)

    2016-07-01

    We have prepared a novel 3D porous biomaterial combining poly (DL-lactic acid) (PDLLA) and graphene and multi-walled carbon nanotubes oxides (MWCNTO-GO) composite. PDLLA as control and a high loading of PDLLA/MWCNTO-GO (50/50 w/w) bioscaffolds were prepared and functionalized. MWCNTs were exfoliated to form MWCNTO-GO by oxygen plasma etching. The later was also applied to enhance the scaffolds wettability, attaching oxygen-containing groups on their surfaces. This approach produced a porous architecture observed by scanning electron microscopy and semi-quantified by electrochemical analysis. The later also indicated a notable increase on the conductivity of PDLLA/MWCNTO-GO scaffold compared to MWCNTO-GO free PDLLA (about 5 orders of magnitudes at low frequencies). Thermogravimetric analysis showed that the MWCNTO-GO acted protecting the PDLLA matrix, enhancing its thermal stability. The PDLLA/MWCNTO-GO scaffolds had significant cellular adhesion, did not present cytotoxicity effect, besides reduced bactericidal proliferation and produced mineralized tissues in SBF media. The metallic MWCNTO-GO powder held together by PDLLA polymer opens a whole new branch of applications, including bioelectroanalyses, drug delivery systems and tissue engineering. - Highlights: • We produced a novel 3D porous material from PDLLA, graphene oxide and MWCNT oxide. • MWCNTO-GO loading (50/50 w/w) increased notably the conductivity of PDLLA scaffold. • MWCNTO-GO acted protecting the PDLLA matrix, enhancing its thermal stability. • PDLLA/MWCNTO-GO scaffolds did not present cytotoxicity effect. • PDLLA/MWCNTO-GO scaffolds presented bioactivity properties.

  16. Recombinant protein truncation strategy for inducing bactericidal antibodies to the macrophage infectivity potentiator protein of Neisseria meningitidis and circumventing potential cross-reactivity with human FK506-binding proteins.

    Science.gov (United States)

    Bielecka, Magdalena K; Devos, Nathalie; Gilbert, Mélanie; Hung, Miao-Chiu; Weynants, Vincent; Heckels, John E; Christodoulides, Myron

    2015-02-01

    A recombinant macrophage infectivity potentiator (rMIP) protein of Neisseria meningitidis induces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human proteins, we immunized mice with recombinant truncated type I rMIP proteins that lacked the globular domain and the signal leader peptide (LP) signal sequence (amino acids 1 to 22) and contained the His purification tag at either the N or C terminus (C-term). The immunogenicity of truncated rMIP proteins was compared to that of full (i.e., full-length) rMIP proteins (containing the globular domain) with either an N- or C-terminal His tag and with or without the LP sequence. By comparing the functional murine antibody responses to these various constructs, we determined that C-term His truncated rMIP (-LP) delivered in liposomes induced high levels of antibodies that bound to the surface of wild-type but not Δmip mutant meningococci and showed bactericidal activity against homologous type I MIP (median titers of 128 to 256) and heterologous type II and III (median titers of 256 to 512) strains, thereby providing at least 82% serogroup B strain coverage. In contrast, in constructs lacking the LP, placement of the His tag at the N terminus appeared to abrogate bactericidal activity. The strategy used in this study would obviate any potential concerns regarding the use of MIP antigens for inclusion in bacterial vaccines.

  17. Mucosal vaccination against serogroup B meningococci: induction of bactericidal antibodies and cellular immunity following intranasal immunization with NadA of Neisseria meningitidis and mutants of Escherichia coli heat-labile enterotoxin.

    Science.gov (United States)

    Bowe, Frances; Lavelle, Ed C; McNeela, Edel A; Hale, Christine; Clare, Simon; Arico, Beatrice; Giuliani, Marzia M; Rae, Aaron; Huett, Alan; Rappuoli, Rino; Dougan, Gordon; Mills, Kingston H G

    2004-07-01

    Conjugated polysaccharide vaccines protect against serogroup C meningococci. However, this approach cannot be applied to serogroup B, which is still a major cause of meningitis. We evaluated the immunogenicity of three surface-exposed proteins from serogroup B Neisseria meningitidis (App, NhhA, and NadA) identified during whole-genome sequencing. Mice were immunized intranasally with individual proteins in the presence of wild-type Escherichia coli heat-labile enterotoxin (LTwt), LTR72, a partially inactivated mutant, or LTK63, a completely nontoxic mutant, as the adjuvant. Each of the meningococcal proteins induced significant cellular responses; NhhA and NadA induced strong antibody responses, but only NadA induced bactericidal antibody when administered intranasally with mucosal adjuvants. In addition, immunoglobulin A and bactericidal antibodies were detected in the respiratory tract following intranasal delivery of NadA. Analysis of antigen-specific cytokine production by T cells from immunized mice revealed that intranasal immunization with NadA alone failed to generate detectable cellular immune responses. In contrast, LTK63, LTR72, and LTwt significantly augmented NadA-specific gamma interferon, interleukin-4 (IL-4), IL-5, and IL-10 production by spleen and lymph node cells, suggesting that both Th1 and Th2 cells were induced in vivo. The strongest cellular responses and highest bactericidal antibody titers were generated with LTR72 as the adjuvant. These findings demonstrate that the quality and magnitude of the immune responses generated by mucosal vaccines are influenced by the antigen as well as the adjuvant and suggest that nasal delivery of NadA with mucosal adjuvants has considerable potential in the development of a mucosal vaccine against serogroup B meningococci.

  18. STUDY ON BACTERICIDAL EFFICACY OF A QUATERNARY AMMONIUM COMPOUNDS DISINFECTANT TO LEGIONELLA PNEUMOPHILA%一种复方季铵盐类消毒液杀灭嗜肺军团菌效果的研究

    Institute of Scientific and Technical Information of China (English)

    蔡怡珊; 刘海涛; 黄金宝; 张柳; 周艳

    2011-01-01

    Objective To study the bactericidal efficacy and influencing factors of a quaternary ammonium compounds disinfectant to Legionella pneumophila. Methods Suspension quantitative bactericidal test was performed to observe the germicidal efficacy to L. pneumophila of didecyldimethylammonium chloride compounds disinfectant and the influencing factors. Results The killing log value of L. pneumophila was above 5.0 when the quaternary ammonium compounds disinfectant containing 59.2 mg/L active ingredient contact with 5 minutes. The bactericidal efficacy was enhanced with increasing disinfectant concentration and prolonging contact time. The bactericidal efficacy was decreased with the down of pH. Conclusion The quaternary ammonium compounds disinfectant can kill L. pneumophila at low concentration, but acidic pH can decrease its germicidal efficacy.%目的 研究一种复方季铵盐消毒剂对嗜肺军团菌杀灭效果及其影响因素.方法 应用悬液定量杀菌试验方法,对以二癸基二甲基氯化铵为杀菌成分的复方季铵盐消毒液杀灭嗜肺军团菌的效果及其影响因素进行了观察.结果 以活性物含量为59.2 mg/L的该复方季铵盐消毒剂对悬液内嗜肺军团菌作用5 min,平均杀灭对数值>5.0.该复方季铵盐消毒剂随浓度增加和作用时间延长,其杀菌作用增强;但其随消毒液pH值降低,杀菌作用减弱.结论 该复方季铵盐消毒剂在较低浓度下对嗜肺军团杆菌杀灭效果较好,但消毒液pH值偏酸性会降低其杀菌效果.

  19. 聚维酮碘对气单胞菌的抑菌杀菌效果研究%Research on Bacteriostatic and Bactericidal Efficacy of Povidone Iodine on Aeromonas

    Institute of Scientific and Technical Information of China (English)

    谭凤霞

    2011-01-01

    [目的]研究聚维酮碘作为一种水产养殖上常用的消毒剂对气单胞菌的抑菌杀菌效果。[方法]以气单胞菌属标准株ATCC7966和分离自患病鱼及养殖环境的气单胞菌为试验菌株,通过肉汤二倍稀释法研究聚维酮碘的抑菌杀菌作用。[结果]聚维酮碘在低浓度时能抑制气单胞菌的生长增殖,高浓度时杀灭细菌,其对Aeromonas sp. T1、Aeromonas sp. T2、Aeromonas sp. T4菌株的最小抑菌浓度为125. 00mg/L,最小杀菌浓度为4.00g/L;其对ATCC7966、Aeromonas sp. T3、Aeromonas sp. T5、Aeromonas sp. T6菌株的最小抑菌浓度为250.00 mg/L,最小杀菌浓度为8.00 g/L。[结论]为聚维酮碘的合理使用提供了一定的依据。%[Objective] The aim of this study is to investigate the bacteriostatic and bactericidal efficacy of povidone iodine as one kind of disinfectants for aquaculture on Aeromonas.[Method] With the standard strain of Aeromonas ATCC7966 and the Aeromonas strains isolated from diseased fish or aquatic environment as the tested strains,the bacteriostatic and bactericidal efficacy of povidone iodine was studied by double broth dilution method.[Result] The povidone iodine could inhibit the growth of Aeromonas strains at lower concentration,and killed Aeromonas strains at higher concentration.The minimum bacteriostatic concentration(MIC) of povidone iodine on Aeromonas sp.T1,Aeromonas sp T2 and Aeromonas sp.T4 was 125.00 mg/L,and the minimum bactericidal concentration(MBC) was 4.00 g/L.Whereas,the minimum bacteriostatic concentration(MIC) of povidone iodine on ATCC7966,Aeromonas sp.T3,Aeromonas sp T5 and Aeromonas sp.T6 was 250.00 mg/L,and the minimum bactericidal concentration(MBC) was 8.00 g/L.[Conclusion] This study provides certain basis for reasonable application of povidone iodine.

  20. 聚维酮碘对气单胞菌的抑菌杀菌效果研究%Research on Bacteriostatic and Bactericidal Efficacy of Povidone Iodine on Aeromonas

    Institute of Scientific and Technical Information of China (English)

    谭凤霞

    2011-01-01

    [Objective] The aim of this study is to investigate the bacteriostatic and bactericidal efficacy of povidone iodine as one kind of disinfectants for aquaculture on Aeromonas. [ Method] With the standard strain of Aeromonas ATCC7966 and the Aeromonas strains isolated from diseased fish or aquatic environment as the tested strains, the bacteriostatic and bactericidal efficacy of povidone iodine was studied by double broth dilution method. [Result] The povidone iodine could inhibit the growth of Aeromonas strains at lower concentration, and killed Aeromonas strains at higher concentration. The minimum bacteriostatic concentration (MIC) of povidone iodine on Aeromonas sp. T1, Aeromonas sp. T2 and Aeromonas sp. T4 was 125.00 mg/L, and the minimum bactericidal concentration (MBC) was4.00 g/L. Whereas, the minimum bacteriostatic concentration (MIC) of povidone iodine on ATCC7966, Aeromonas sp. T3, Aeromonas sp. T5 and Aeromonas sp. T6 was 250.00 mg/L, and the minimum bactericidal concentration (MBC) was 8.00 g/L. [ Conclusion] This study provides certain basis for reasonable application of povidone iodine.%[目的]研究聚维酮碘作为一种水产养殖上常用的消毒剂对气单胞菌的抑菌杀菌效果.[方法]以气单胞菌属标准株ATCC7966和分离自患病鱼及养殖环境的气单胞菌为试验菌株,通过肉汤二倍稀释法研究聚维酮碘的抑菌杀菌作用.[结果]聚维酮碘在低浓度时能抑制气单胞菌的生长增殖,高浓度时杀灭细菌,其对Aeromonas sp.T1、Aeromonas sp.T2、Aeromonas sp.T4菌株的最小抑菌浓度为125.00 mg/L,最小杀菌浓度为4.00 g/L;其对ATCC7966、Aeromonas sp.T3、Aeromonas sp.T5、Aeromonas sp.T6菌株的最小抑菌浓度为250.00mg/L,最小杀菌浓度为8.00g/L.[结论]为聚维酮碘的合理使用提供了一定的依据.

  1. 天然高分子改性异喹啉季铵盐对SRB杀菌性能及机理的研究%A Study of Bactericidal Effect of Natural Polymeric Modified Isoquinoline Quaternary Ammonium Salt on Sulfate Reducing Bacteria(SRB) and Mechanism

    Institute of Scientific and Technical Information of China (English)

    潘碌亭; 肖锦

    2001-01-01

    The bactericidal effect of natural polymeric modified isoquinoline quaternary ammonium salt(FIQ-C)on sulfate reducing bacteria (SRB) was studied using the vanishing- dilution method. Factors affecting the bactericidal ef- ficiency were investigated, the bectericidal ability of FIQ-C was compared with that of 1227, and the bactericidal mechanism of FIQ-C was approached. The result shows that FIQ - C has a good bactericidal effect on the SRB in sim- ulated oil field waste water and that when the addition of FIQ - C is 5 mg/L, the bactericidal rate may be 99.9% or higher.%采用绝迹稀释法研究了天然高分子改性异喹啉季铵盐(FIQ-C)对硫酸盐还原菌(SRB)的杀灭性能。考察了各种因素对杀菌性能的影响,比较了药剂FIQ-C与1227的杀菌能力,探讨了FIQ-C的杀菌机理。结果表明,药FIQ-C对模拟油田废水中SRB有良好的杀灭性能,当FIQ-C投加量为5 mg/L时,杀菌率可达99.9%以上。

  2. Function and Application Prospect of Bactericidal/Permeability-increasing Protein%杀菌/渗透性增强蛋白功能及应用前景

    Institute of Scientific and Technical Information of China (English)

    颜金鹏; 王丽; 李善妮; 邓丽明; 韩旭

    2011-01-01

    The bactericidal/permeability-increasing protein ( BPI) is a multifunctional cationic protein with the molecular mass about 55 kD. BPI is stored mainly in the azurophilic granules of the poly-morphonuclear neutrophils. It binds lipopolysaccharide on the outer membrane of gram-negative bacteria and increases the membrane permeability to kill the bacteria. BPI can also neutralize and clear the endotoxins, therefore can be used in the prevention and treatment of disease derived from gram-negative bacteria infection. Recently, BPI was also found to have other functions, such as neutrophil-mediated phagocytosis related opsonic function, fungistasis, anti-protozoan parasite, and angiogenesis inhibition activities. This review focuses on the localization, the structural and functional properties of BPI, and its functions in host defense during gram-negative bacteria infections and endotoxin-induced inflammation. The clinical application of BPI was also prospected.%杀菌/通透性增强蛋白(BPI)是存在于中性粒细胞中的阳离子蛋白,约为55 kD.BPI能与革兰氏阴性菌外膜上的脂多糖结合,增加外膜对抗菌药的通透性,具有特异性杀灭革兰氏阴性菌及结合/中和内毒素的生物学功能,在革兰氏阴性菌感染的治疗方面有良好的发展前景.近年来,国内外对BPI研究颇多,并逐渐发现BPI还具有调理作用、抗真菌、抗原虫和抑制血管生成等许多功能,被学者称为未来的"超级抗生素".本文主要就BPI的结构、分布、生理功能、作用机理及临床研究方面的研究进展作一综述.

  3. In vitro analysis on bactericidal screening and antioxidant potentiality of leaf and root extracts of Thottea siliquosa (Lam.) Ding Hou. An ethnobotanical plant

    Institute of Scientific and Technical Information of China (English)

    Saiba Abdul Wahab Nusaiba; Kumaraswamy Murugan

    2013-01-01

    Objective: Natural products of plant origin are potential source of novel antimicrobial and antioxidative agents. Thottea siliquosa (Lam.) Ding Hou. (T. siliquosa). A medicinal herb used by local tribals for treating various ailments. The present study aims at the phytochemical screening, GC-MS analysis, in vitro antibacterial activity and antioxidant potentiality of root and leaf extracts of T. siliquosa.Methods:Hot continuous Soxhlet extraction, GC-MS analysis, antibacterial analysis by disc diffusion, microdilution assay and antioxidant potentialities by hydroxyl radical and nitric oxide radical scavenging. The data was statistically analyzed. Results: Phytochemical screening of the ethyl acetate and methanolic extract of leaf and root revealed the presence of phenols, alkaloids, tannins and saponin. The extract revealed a pool of phytochemicals by comparison with authentic standards from spectral library. Both the extracts has shown their broad spectrum of inhibition against the selected bacteria Staphylococcus aureus,Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia compared with standard antibiotic drug streptomycin. The extracts showed antioxidant activity by scavenging of free radicals such as hydroxyl and nitric oxide. The IC50 values of the ethyl acetate extracts leaf and root and standard in this assay were 167.5±0.67, 99.4±1.2, 192±2.5 µg/mL respectively. Similarly those methanolic extracts of leaf and root were 269.5±0.89 and 289.1±2.66 µg/mL respectively. Similarly, ethyl acetate and methanolic extracts also caused a moderate dose-dependent inhibition of nitric oxide with an IC50 range 65.5±1.55 to 148 ±3.09 µg/mL. The inhibitory activities were found to be dose dependent.Conclusion:The present study provides evidence that ethyl acetate and methanol extract of leaf and root of T. siliquosa are potential source of natural antioxidants and bactericidal nature. It is essential that research should continue to isolate and purify

  4. Growth inhibitory, bactericidal, and morphostructural effects of dehydrocostus lactone from Magnolia sieboldii Leaves on antibiotic-susceptible and -resistant strains of Helicobacter pylori.

    Science.gov (United States)

    Lee, Hyun-Kyung; Song, Ha Eun; Lee, Haeng-Byung; Kim, Cheol-Soo; Koketsu, Mamoru; Ngan, Luong Thi My; Ahn, Young-Joon

    2014-01-01

    Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL) from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide), (-)-epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L) was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L). The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain), clarithromycin (49.8 mg/L for PED 3582GA strain), metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain), or tetracycline (14.2 mg/L for B strain) was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0-7.0). DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h). The Western blot analysis revealed that urease subunits (UreA and UreB) of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (-)-epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori.

  5. Growth inhibitory, bactericidal, and morphostructural effects of dehydrocostus lactone from Magnolia sieboldii Leaves on antibiotic-susceptible and -resistant strains of Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Hyun-Kyung Lee

    Full Text Available Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide, (--epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L. The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain, clarithromycin (49.8 mg/L for PED 3582GA strain, metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain, or tetracycline (14.2 mg/L for B strain was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0-7.0. DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h. The Western blot analysis revealed that urease subunits (UreA and UreB of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (--epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori.

  6. The bactericidal efficiency of electrolyzed water on Enterococcus faecalis biofilm%电解质水对粪肠球菌生物膜的杀菌作用研究

    Institute of Scientific and Technical Information of China (English)

    赵春苗; 程小刚; 范晓敏; 任世荣; 白玉; 于丁一; 余擎

    2013-01-01

    目的:观察强酸性电解质水(SAEW)和碱性电解质水(AEW)对粪肠球菌生物膜的杀菌作用.方法:利用BioFluxTM 200微流体系统建立粪肠球菌生物膜模型,并分别用SAEW、AEW、52.5 g/L次氯酸钠液(阳性对照)和生理盐水(阴性对照)处理1、5、10 min后,激光共聚焦显微镜(CLSM)观察并采集荧光图像;ImageJ图像分析软件分析并计算各处理组不同时间点的活菌比例.结果:SAEW、AEW和52.5 g/L次氯酸钠液处理1、5、10 min各时间点的活菌比例都显著低于生理盐水组(P<0.05),其中AEW组活菌比例下降幅度最小,与SAEW和52.5 g/L次氯酸钠液处理组相比,各时间点均有统计学差异(P<0.05);而SAEW与52.5 g/L次氯酸钠液处理组相比,各时间点的活菌比例均无统计学差异(P>0.05).结论:SAEW和AEW对粪肠球菌均有杀菌作用,其中SAEW的作用与52.5 g/L次氯酸钠液相当;而AEW的杀菌效果较弱,且需要延长作用时间.%AIM: To evaluate the bactericidal efficiency of strong acid electrolyzed water (SAEW) and alkaline electrolyzed water (AEW) on Enterococcus faecalis biofilm. METHODS: The Enterococcus faecalis dilution was added to the BioFlux? 200 system to form biofilm. The biofilm was then treated with SAEW and AEW for 1 min, 5 min and 10min respectively. 52. 5 g/L NaCIO and normal saline (NS) were used as the positive and negative controls. Confocal laser scanning microscopy ( CLSM) was used to evaluate the bactericidal efficiencies. ImageJ was used to analyze the fluorescence images. RESULTS: At all time points, the survival rates of Enterococcus faecalis in SAEW and AEW groups were significantly lower than that in NS group ( P 0.05). However, AEW group showed higher survival rate than SAEW and 52. 5 g/L NaCIO groups (P <0.05). CONCLUSION: Both SAEW and AEW showed bactericidal effects on Enterococcus faecalis. SAEW has similar bactericidal efficacy with NaCIO, however the bactericidal efficiency of AEW was much weaker.

  7. Efecto bactericida del láser Nd: YAP. Estudio in vitro Bactericidal effects of Nd: YAP. An in vitro study

    Directory of Open Access Journals (Sweden)

    G Caccianiga

    2007-06-01

    bacterial charge of stocks commonly present in active periodontal pockets. The five bacterial stocks studied are: Haemophilus actinomycetemcomitans, Bacteroides forsytus, Porphyromonas gingivalis, Micromonas micron, Fusobacterium nucleatem. The laboratory method used foresees the following protocol: 30 ml of each bacterial suspension has been exposed to hydrogen peroxide at diverse concentrations at 0.5% or at 3% and it has been irradiated separately with laser for 5 seconds or 10 seconds, using sterile 1.5 ml Eppendorf tubes. It has been compared thus the bacterial activity of the hydrogen peroxide alone at the concentrations of 0.5% and 3%, the bacterial activity of the laser irradiation alone and of the two associated treatments. In every bacterial cultivation examined the use of hydrogen peroxide at 3% concentration associated with the 10 second laser irradiation exposure led to the absence or a marked decrease of the number of bacterial colonies, while the decrease has been less evident or absent in the case of the two treatments used separately. The results confirm the higher bactericide effectiveness of the combined action of hydrogen peroxide and laser.

  8. EVALUACIÓN in vitro DEL EFECTO BACTERICIDA DE CEPAS NATIVAS DE Lactobacillus sp. CONTRA Salmonella sp. y Escherichia coli In vitro EVALUATION OF THE BACTERICIDAL EFFECT OF NATIVE STOCKS OF Lactobacillus sp. AGAINST Salmonela sp. AND Echerichia coli

    Directory of Open Access Journals (Sweden)

    Ana Cristina Estrada Maldonado

    2005-06-01

    Full Text Available En esta investigación se trabajó con dos cepas nativas de Lactobacillus plantarum y Lactobacillus brevis, aisladas de productos fermentados; estas crecen en medios de cultivo y producen un extracto complejo de ácidos orgánicos y péptidos con actividad bactericida. Los extractos de estas cepas mostraron capacidad bactericida frente a Salmonella sp. y Escherichia coli. Los ensayos para determinar su acción se realizaron con el extracto crudo y centrifugado provenientes de cada una de las cepas, a diferentes tiempos de almacenamiento, temperatura y pH. Se observó una mejor actividad antibacteriana y estabilidad de la actividad, en el extracto crudo almacenado a temperatura de 0ºC y 4ºC. A pH 5.5 se presento la mejor actividad en los dos extractos frente a las cepas de estudio. Se concluyó que los extractos sintetizados por ambas cepas tienen un alto potencial bactericida contra estas dos patógenos que son responsables de toxi-infecciones alimentarias.In this investigation, two native stocks of Lactobacillus plantarum and Lactobacillus brevis isolated from fermented products were studied; these grow in culture media and produce a complex extract of organic acids and peptides with bactericidal activity. The extracts of these stocks showed bactericidal capacity with Salmonella sp. and Escherichia coli. The tests to determine their action were made with crude and centrifuged extract originating of each one of the stocks, with different storage times, temperatures and pHs. A superior antibacterial activity and stability of the activity was observed in the crude extract stored in temperatures of 0ºC and 4ºC. With pH 5,5 the best activity of the two extracts against the study stocks was obtained. It is concluded that the extracts synthesized by both stocks have a high bactericidal potential against these two pathogens that are responsible for nutritional toxi-infections.

  9. Effect of the Glutaraldehyde on the Bacteriostatic and Bactericide of Aeromonas%戊二醛对气单胞菌的抑菌杀菌效果研究

    Institute of Scientific and Technical Information of China (English)

    谭凤霞; 陈和东; 叶聪

    2011-01-01

    [目的]研究戊二醛对气单胞菌的杀菌效果,为戊二醛在水产养殖上的合理使用提供依据.[方法]以气单胞菌属标准株ATCC7966和分离自养殖环境及患病鱼的气单胞菌为试验菌株,通过肉汤二倍稀释法研究.[结果]戊二醛在低浓度时能抑制气单胞菌的生长增殖,高浓度杀灭细菌,其对7株气单胞菌的最小抑菌浓度(MIC)均为7.8mg/L,其最小杀菌浓度为62.5 mg/L( ATCC7966、Aeromonas sp.T3、Aeromonas sp.T5、Aeromonas sp.T6)和125 mg/L( Aeromonas sp.T1、Aeromonas sp.T2、Aeromonas sp.T4).[结论]为戊二醛的合理使用提供一定的依据.%[Objective] The basis of the reasonable utilization of glutaraldehyde in aquaculture production was provided through the research on its effect on the bactericide of Aeromonas. [Method] The standard strain of Aeromonas - - ATCC7966 and the Aeromonas strain isolated from fish - raising environment or from diseased fish was taken as the tested strain and the efficacy of the glutaraldehyde on the bacteriostatic and bactericide of Aeromonas was determined with the method of double broth dilution. [ Results ] The results showed that the glutaraldehyde could inhibit the growth of bacterium at the low concentration and kill the bacterium at the high concentration. The minimal inhibitory concentration ( MIC) of glutaraldehyde to 7 Aeromonas strains was 7. 8mg/l and the minimal bactericidal concentration( MBC) of glutaraldehyde to 4 Aeromonas strains including ATCC7966, Aeromonas sp. T3, Aeromonas sp. T5 and Aeromonas sp. T6 was 62.5 mg/1 and 3 Aeromonas strains including Aeromonas sp. Tl, Aeromonas sp. T2 and Aeromonas sp. T4 was 125mg/l. [ Conclusion] The experimental results could provide the scientific basis of the reasonable application of glutaraldehyde.

  10. 立奇膏联合百克瑞治疗糖尿病足的临床研究%Clinical study on Bactericide soaked gauze combined with Liqi ointment for treatment of patients with diabetic foot

    Institute of Scientific and Technical Information of China (English)

    赵志芳; 张敏; 朱月珍

    2015-01-01

    Objective:To explore the nursing effect of self made Liqi ointment combined with bactericide soaked gauze for treatment of patients with diabetic foot ulcer.Methods:A total of 80 patients with 2~4 level diabetic foot ulcer from out patient clinic and in patients were selected and randomly divided into treatment group and control group,40 cases in each.On the basis of same comprehensive treatment,the patients in control group were trea-ted only with bactericide soaked gauze for wound treatment and the patients in treatment group were com-pressed with self made Li Qi Ointment after wet compressing with bactericide soaked gauze.The differences of total effective rate were compared after intervention.Results:After 12 weeks of intervention,the wound area in treatment group patients was reduced,and the painful feeling in dressing was relieved and then the fasting glu-cose of patients was basically reduced to the normal range.The total effective rate of 95.0%,which was signifi-cantly higher than that in control group(P <0.05).Conclusion:The self made Li Qi ointment combined with bactericide soaked gauze has significantly effect for patients with 2~4 grade diabetic foot ulcer,and it is an ef-fective,safe and economic method.%[目的]探索采用自制中药“立奇膏”联合百克瑞纱布治疗糖尿病足溃疡的护理效果。[方法]选择门急诊及住院2级~4级糖尿病足溃疡病人80例,随机分为治疗组和对照组各40例,在相同综合治疗基础上,对照组常规选用百克瑞纱布湿敷进行伤口处理;治疗组百克瑞纱布湿敷后外敷自制中药“立奇膏”进行伤口处理,干预结束后比较两组总有效率。[结果]干预12周后,治疗组创面面积缩小,换药时疼痛感减轻,空腹血糖基本降至正常范围,总有效率达95.0%,明显优于对照组,两组比较差异具有统计学意义(P <0.05)。[结论]自制中药“立奇膏”联合百克瑞纱布湿敷治疗2级~4级糖尿病足

  11. 芫荽软腐病病原菌生物学特性与药剂筛选%Biology Characters and Bactericide Screening of Pathogen of Coriander Soft Rot

    Institute of Scientific and Technical Information of China (English)

    张立微; 张景涛; 张丽茁; 李小梅; 戴忠仁

    2015-01-01

    为有效防治芫荽软腐病,对其病原菌进行生物学特性及其药敏筛选试验研究。结果表明:芫荽软腐病病原菌在37℃条件下,土壤p H为7时导致芫荽植株发病加速。在药剂筛选试验中,通过抑菌圈法可知,7种试验药剂中72%农用硫酸链霉素可溶性粉剂、3%噻霉酮可湿性粉剂、53.8%氢氧化铜水分散粒剂、20%噻菌铜悬浮剂均有明显抑菌作用。其中,72%硫酸链霉素可溶性粉剂的抑菌作用最强,最小抑菌浓度为0.031%;其次为3%噻霉酮可湿性粉剂,最小抑菌浓度为0.06%。%For effective prevention and control of coriander soft rot ,biology characters and bactericide screening of pathogen of coriander soft rot were studied .The result showed that coriander soft rot could be accelerated plant disease under 37℃ and pH 7 .0 of soil .According to bactericide screening ,72% Streptomycin SP ,3% Ben‐ziothiazolinone WP ,53 .8% Copper hydroxide WDG ,20% Thiodiazole‐copper SC were effected to coriander soft rot .Minimum inhibitory concentration of 72% Streptomycin SP was 0 .031% ;secondly ,minimum inhibitory concentration of 3% Benziothiazolinone WP was 0 .06% .

  12. Decrease in Shiga toxin expression using a minimal inhibitory concentration of rifampicin followed by bactericidal gentamicin treatment enhances survival of Escherichia coli O157:H7-infected BALB/c mice

    Directory of Open Access Journals (Sweden)

    Abdelnoor Alexander M

    2011-09-01

    Full Text Available Abstract Background Treatment of Escherichia coli O157:H7 infections with antimicrobial agents is controversial due to an association with potentially fatal sequelae. The production of Shiga toxins is believed to be central to the pathogenesis of this organism. Therefore, decreasing the expression of these toxins prior to bacterial eradication may provide a safer course of therapy. Methods The utility of decreasing Shiga toxin gene expression in E. coli O157:H7 with rifampicin prior to bacterial eradication with gentamicin was evaluated in vitro using real-time reverse-transcription polymerase chain reaction. Toxin release from treated bacterial cells was assayed for with reverse passive latex agglutination. The effect of this treatment on the survival of E. coli O157:H7-infected BALB/c mice was also monitored. Results Transcription of Shiga toxin-encoding genes was considerably decreased as an effect of treating E. coli O157:H7 in vitro with the minimum inhibitory concentration (MIC of rifampicin followed by the minimum bactericidal concentration (MBC of gentamicin (> 99% decrease compared to treatment with gentamicin alone (50-75% decrease. The release of Shiga toxins from E. coli O157:H7 incubated with the MIC of rifampicin followed by addition of the MBC of gentamicin was decreased as well. On the other hand, the highest survival rate in BALB/c mice infected with E. coli O157:H7 was observed in those treated with the in vivo MIC equivalent dose of rifampicin followed by the in vivo MBC equivalent dose of gentamicin compared to mice treated with gentamicin or rifampicin alone. Conclusions The use of non-lethal expression-inhibitory doses of antimicrobial agents prior to bactericidal ones in treating E. coli O157:H7 infection is effective and may be potentially useful in human infections with this agent in addition to other Shiga toxin producing E. coli strains.

  13. 风信子软腐病病原的鉴定和杀菌剂试验%Rapid Identification of Soft Rot Pathogen and Bactericidal Test in Hyacinthus orientalis

    Institute of Scientific and Technical Information of China (English)

    李冰; 马晓红; 沈强; 顾俊杰; 史益敏

    2011-01-01

    Based on 16S rDNA sequence analysis and traditional identified methods, a strain of EP was purified from hyacinth rotting bulb in Shanghai, and was identified as Erwinia carotovora subsp. Carotovora. There is 97% homology between the EP strain and Erwinia carotovora subsp. Carotovora. The bactericidal test showed that 0. 64 X 10-6 g/mL of Mancozeb (Syngenta product) has more effective bactericidal ability, followed by 5. 76 X 10-4 g/mL of streptomycin and 2 X 10-4 g/mL Moroxydine B Copper.%在上海生长的风信子发生软腐病的球茎中分离了菌株EP,对纯化的菌株EP进行传统方法鉴定;并进行16S rDNA序列同源性分析,结果表明EP与Erwinia carotovora subsp.carotovora 同源性达到97%,确定风信子软腐病病原为Erwinia carotovora subsp.carotovora.风信子软腐病病菌在不同杀菌剂浓度下的生长试验表明,杀毒矾抑菌效果最好,有效浓度0.64×10-6g/mL时细菌停止生长,其次为吗啉胍乙铜和农用链霉素可溶性粉剂,有效浓度分别为2×10-4 g/mL和5.76×10-4g/mL时,细菌停止生长.

  14. Bactericidal effect of a novel peptide on oral microorganisms%新型优化多肽对口腔常见微生物的杀菌作用

    Institute of Scientific and Technical Information of China (English)

    营秀; 孙应明; 陶睿; 张梦洁; 姜秀

    2016-01-01

    目的:抗菌肽是近来口腔微生物研究的热点,文中研究新型抗菌多肽pm11对口腔常见微生物的抗菌作用及机制。方法通过测定pm11对口腔常见微生物的最小抑菌浓度( minimal inhibitory concentration , MIC)、最小杀菌浓度( mini-mal bactericide concentration , MBC)及杀菌动力学曲线的方法,分析其对游离细菌的作用,以及测定唾液环境下pm11的抑菌圈直径分析其在口腔环境中的杀菌能力,利用激光共聚焦显微镜观察对变异链球菌生物膜的杀菌作用,利用扫描电镜( SEM )观察细菌表面的结构变化。结果 pm11对8种微生物具有抗菌活性,且抗菌活性相差很大, MIC范围为2~256μg/mL,MBC波动范围为4μg/mL至>256μg/mL。杀菌动力学结果显示致龋菌随着pm11作用时间的增加,存活细菌数显著下降。抑菌圈pm11的唾液组和超纯水组没有明显差异,CLSM结果表明生物膜内有死菌存在,SEM结果直观地看到pm11作用下的细菌细胞膜表面有明显的孔洞、细胞皱缩、细菌溶胀及细胞裂解或碎片。结论 pm11具有广谱的杀菌作用,具有潜在的实用价值和临床指导意义。%Objective Antimicrobial peptides are the focus of recent research in oral microbiology .This study aimed to eval-uate the activity of a novel antimicrobial peptide pm 11 against oral microorganisms and its action mechanisms . Methods We ana-lyzed the effect of pm11 on oral microorganisms and determined its antimicrobial activity in the saliva environment by measuring its min -imal inhibitory concentration (MIC), minimal bactericide concentration (MBC), and bactericidal kinetics.We observed its bacteri-cidal activity on the biofilms of streptococcus mutans by confocal laser scanning microscopy (CLSM) and the structural changes in the bacterial membrane by scanning electron microscopy (SEM). Results The antimicrobial activity of pm11 varied greatly against

  15. Comparative study on bactericidal activity of benzalkonium chloride and dodecyl two propylene triamine%苯扎氯铵与十二烷基二亚丙三胺杀菌活性比较研究

    Institute of Scientific and Technical Information of China (English)

    张丽蓉; 陈维; 邓金花; 宋金武

    2016-01-01

    Objective To compare bactericidal activity of benzalkonium chloride and dodecyl two propylene triamine.Methods Suspension quantitative germicidal test and antibacterial ring test were used to study bactericidal activity of benzalkonium chloride and dodecyl two propylene triamine.Results The average killing logarithm values of Pseudomonas aeruginosa,Escherichia coli and Staphylococcus aureus exposed to the concentration of 500 mg/L of the benzalkonium chloride for 1 min were 5.18,7.02 and 7.13 respectively,the average killing logarithm value of Candida albicans was 4.48.The average killing logarithm values of P.aeruginosa,E.coli and S.aureus exposed to the concentration of 500 mg/L of the dodecyl two propylene triamine for 1 min were 5.84,7.32 and 7.13 respectively,the average killing logarithm value of C.albicans was 4.94.Concentration was 50 mg/L,the antibacterial ring diameters of benzalkonium chloride and dodecyl two propylene triamine were 8.3 mm and 8.2 mm respectively.Conclusion The bactericidal effect of dodecyl two propylene triamine is better than that of benzalkonium chloride,there was no significant difference in antibacterial effect.%目的 比较苯扎氯铵与十二烷基二亚丙三胺的杀菌活性.方法 采用悬液定量杀菌试验和抑菌环试验方法,对苯扎氯铵和十二烷基二亚丙三胺的杀菌活性进行比较研究.结果 用含500 mg/L的苯扎氯铵作用1 min,对铜绿假单胞菌、大肠杆菌和金黄色葡萄球菌的平均杀灭对数值分别为5.18、7.02和7.13,对白色念珠菌的平均杀灭对数值为4.48.用含500 mg/L的十二烷基二亚丙三胺作用1 min,对铜绿假单胞菌、大肠杆菌和金黄色葡萄球菌的平均杀灭对数值分别为5.84、7.32和7.13,对白色念珠菌的平均杀灭对数值为4.94.浓度为50 mg/L时,苯扎氯铵与十二烷基二亚丙三胺的抑菌环直径分别为8.3 mm和8.2 mm.结论 十二烷基二亚丙三胺的杀菌效果优于苯扎氯铵,抑菌效果无显著差异.

  16. 过氧乙酸与物理因子协同杀菌作用的研究%STUDY ON THE SYNERGISTIC BACTERICIDAL EFFECT OF PERACETIC ACID WITH OTHER PHYSICAL FACTORS

    Institute of Scientific and Technical Information of China (English)

    钟昱文; 陈惠珍; 王冰姝; 肖红; 王雅静; 张里君; 邹钦

    2011-01-01

    目的 研究超声波、温度与过氧乙酸的协同杀菌作用,为医疗器械消毒实际应用提供依据.方法 采用载体浸泡定量和定性杀菌试验方法,对超声波等物理因子与过氧乙酸协同杀菌效果进行了试验研究.结果 用过氧乙酸750 mg/L单独浸泡作用4 min,对载体上枯草杆菌黑色变种芽孢的平均杀灭率为99.93%;在超声波水槽内含350 mg/L过氧乙酸水溶液加温50℃超声波的协同作用2 min,对载体上枯草芽孢杆菌黑色变种芽孢的杀灭率达100%.用含1 500 mg/L过氧乙酸单独浸泡作用15 min,对载体上枯草杆菌黑色变种芽孢定性培养达到无菌生长;在超声波水槽内含750 mg/L过氧乙酸水溶液加温50~C超声波的协同作用10 min,对载体上枯草杆菌黑色变种芽孢定性培养达到无菌生长.结论 超声波加温50℃与过氧乙酸协同作用,可明显提高过氧乙酸杀灭细菌芽孢的效果,对其用于临床医疗器械消毒具有参考价值%Objective To study the synergistic bactericidal effect of ultrasonic, heat and peracetic acid, and to provide basis for practical application for medical instrument sterilization. Methods Quantitative carrier test and qualitive bactericidal test were taken to evaluate the synergistic bactericidal effect of ultrasound, heat and peracetic acid. Results The killing rate of Bacillus subtilis var. niger spore in carrier exposed to 750 mg/L peracetic acid alone for 4 min was 99.93%,and the killing rate was 100% by dipping in 350 mg/L peracetic acid combined with ultrasound and heating at 50℃ for 2 min in ultrasonic cistern. In Bacillus subtilis var. niger spore qualitive killing test, there was no bacterial growth in carrier after soaking in 1 500 mg/L peracetic acid alone for4 min, and the same effect can be achieved by using 750 mg/L peracetic acid, cooperating with ultrasound and heating at 50℃ for 10 min. Conclusion The effect of bacterial spores killing can be significantly

  17. Bactericidal Activities of Spicy Essential Oils on Microorganisms in Crude Food%香辛料精油成分对生鲜食品中有害菌杀灭活性研究

    Institute of Scientific and Technical Information of China (English)

    段雪娟; 吴克刚; 柴向华

    2012-01-01

    Bactericidal activities of seven spicy essential oil components on five microorganisms (Escherichia Coli, Staphylococcus Awrous, Saimonella, Listcria monocytogenes, Vibrio Parahemolyticus) were studied by plate dilution method and transferring substrate cob method. Results showed that salicylaldehyde had the best bactericidal activity,followed successively by thymol, cin-namic aldehyde, anethole, eugenol, citral, vanillin. The optimal composite essential oil ( salicylaldehyde: cinnamic aldehyde: thymol: anethole 2:5: 20: 5. ) was obtained through orthogonal test. The minimum bactericidal mass concentration of the composite essential oil for killing five pathogens was 0.25 mg/L, only 1/2 of that of salicylaldehyde. Synergistic sterilization effects of composite essential oil was analyzed. The composite essential oil showed a strong synergistic effect on Listeria monocytogenes, an additive effect on Staphylococcus Aurous , Escherichia Coli and Vibrio Parahemolyticus, and unrelated effect on Salmonella.%采用平板稀释法和菌块转移法研究了百里香酚、丁香酚、肉桂醛、茴香脑、水杨醛、柠檬醛、香兰素7种食用植物精油组分对大肠杆菌、金黄色葡萄球菌、沙门氏菌、单增李斯特菌、副溶血性弧菌等生鲜食品常见5种有害菌的杀灭活性.实验结果表明,水杨醛对5种有害菌的综合杀灭能力最强,然后依次是百里香酚、肉桂醛、茴香脑、丁香酚、柠檬醛、香兰素.通过正交试验将水杨醛、肉桂醛、百里香酚、茴香脑复配,得到最佳组合是为:水杨醛、肉桂醛、百里香酚、茴香脑的质量比为2:5:20:5,其杀灭所有供试菌的最低质量浓度为0.25 mg/L,仅为杀菌效果最好的单一水杨醛浓度的1/2.通过对香辛料精油成分杀菌作用协同效应分析得出,复配的香辛精油对单增李斯特菌的杀灭表现出很强的协同增效作用效果,对金黄色葡萄球菌、大肠杆菌和副溶血性弧菌的杀灭

  18. Research on Bacteriostatic and Bactericidal Effect of Chlorine Dioxide on Aeromonas%二氧化氯对气单胞菌的抑菌和杀菌效果研究

    Institute of Scientific and Technical Information of China (English)

    谭凤霞; 吴全超

    2012-01-01

    Aeromonas bacteria strains, including the standard bacteria Aeromonas hydrophila and the Aeromonas bacteria strains which isolated from the culture water or diseased fish, were used to investigate the bacteriostatic and bactericidal efficacy of chlorine dioxide to Aeromonas bacterium by double broth dilution method. The results showed that the chlorine dioxide could inhibit the growth of bacterium at the lower concentration, and killed the bacterium at the higher concentration. The minimal inhibitory concentration (MIC) of chlorine dioxide to seven Aeromonas bacterium are 12 mg/L to strians ATCC7966, Ti, T3, T4, T5; and T6, and 24 mg/L to strain T2; The minimal bactericidal concentration (MBC) of chlorine dioxide to Aeromonas are 96 mg/L to strians ATCC7966, T1, T3 and T4, and 384 mg/L to strains T2, T5 and T6. These results provided the scientific basis for reasonable application of chlorine dioxide.%以嗜水气单胞菌(Aeromonas hydrophila)标准菌株ATCC7966和分离自养殖水环境及患病鲫鱼的气单胞菌(Aeromonas)为试验菌株,通过肉汤二倍稀释法研究二氧化氯的抑菌及杀菌效果.结果表明,二氧化氯在低浓度时能抑制气单胞菌的生长增殖,高浓度时能杀灭细菌,其对ATCC7966、T1、T3、T4、T5、T6菌株的最小抑菌浓度(MIC)为12 mg/L,对T2菌株的最小抑菌浓度为24 mg/L;二氧化氯对ATCC7966、T1、T3、T4菌株的最小杀菌浓度(MBC)为96 mg/L,对T2、T5、T6菌株的最小杀菌浓度为384 mg/L.研究结果能为二氧化氯在水产养殖上的合理使用提供一定的依据.

  19. Determination of Preservatives and Bactericides in Raisins by Solid Phase Extraction-Liquid Chromatography%固相萃取-液相色谱测定葡萄干中防腐杀菌剂

    Institute of Scientific and Technical Information of China (English)

    史龙梅; 李欢; 周建科

    2015-01-01

    With anhydrous sodium sulfate as dispersant , Four kinds of preservatives and bactericides in raisins were extracted by solid phase dispersion method , the C18 solid phase extraction small column was used for purification. Thiabendazole, Baytan, Folpet and Prochloraz were separated by reversed -phase high performance liquid chromatography with C18 column. The mobile phase was the mixture of acetonitrile , methanol and water (50 ∶ 10 ∶ 40,v/v) and detection wavelength was 225 nm. The linearity of regression equations were good in the range of 0.01 μg/mL-200 μg/mL, with correlation coefficients were greater than 0.999 3. Limit of detection is 2.0 ng/g-20.0 ng/g. The relative standard deviations (RSD) were less than 3.18 %. This method is suitable for the analysis of relevant preservatives and bactericides in raisins.%以无水硫酸钠为分散剂,固相分散萃取葡萄干中噻苯咪唑、三唑醇、灭菌丹、咪酰胺4种防腐杀菌剂,C18固相萃取小柱净化处理,高效液相色谱法测定。反相C18色谱柱分离,乙腈-甲醇-水(50∶10∶40,体积比)为流动相,检测波长225 nm。在0.01μg/mL~200μg/mL范围内4组分线性关系良好,相关系数大于0.9993,方法检出限为2.0 ng/g~20.0 ng/g,相对标准小于3.18%,方法适合于葡萄干中相关防腐杀菌剂的检测。

  20. Advances in anti-bactericidal approaches of PMMA denture base resins%聚甲基丙烯酸基托树脂材料抗菌性能研究新进展

    Institute of Scientific and Technical Information of China (English)

    杨杨; 石磊; 宫海环; 宋艾阳; 方滕娇子; 朱松

    2014-01-01

    Long period usage of PMMA denture base follows denture stomatitis, periodontitis and some other oral infectious diseases. A series of anti-microbial approaches have been invented with the properties of self-repair and anti-microbial, such as rechargeable infection responsive denture materials, photolysis of hydrogen peroxide bactericidal system, quaternary ammoniumilane-functionalized, methacrylate resin and organic/inorganic hybrid antibacterial coat-ing. These research achievements represent the latest advances in this field and they will be described in this review.%聚甲基丙烯酸甲酯(Polymethylmethacrylate,PMMA)基托树脂抗菌新方法和独特的抗菌材料,例如可循环使用感染反应性抗真菌基托树脂材料、光分解过氧化氢抗菌体系、新型抗菌单体和抗菌有机-无机杂化涂层材料,能够有效解决患者长期佩戴可摘义齿、活动矫治器导致的义齿口炎、牙周炎等。这些研究成果代表了树脂基托材料抗菌性能研究领域的最新进展,文章将对此进行综述。

  1. Antibody to a 145-kilodalton outer membrane protein has bactericidal activity and protective activity against experimental bacteremia caused by a Brazilian purpuric fever isolate of Haemophilus influenzae biogroup aegyptius. The Brazilian Purpuric Fever Study Group.

    Science.gov (United States)

    Rubin, L G; Rizvi, A

    1991-12-01

    The immunologic basis for protection against Brazilian purpuric fever, a septicemic infection associated with Haemophilus influenzae biogroup aegyptius bacteremia, is unknown. Passive immunization of infant rats with antiserum to whole bacterial cells of the homologous strain protects them from experimental bacteremia following bacterial challenge. In immunoblotting, antibody to a 145-kDa protein (P145) was present in protective antisera but not in nonprotective antisera. As judged by analysis of the antibodies eluted from whole bacterial cells and the agglutination of bacteria by antisera to P145, this protein is surface exposed. We prepared monospecific rat antisera to this protein by three methods: (i) immunization with whole bacterial cells and absorption with a Brazilian purpuric fever strain not expressing P145, (ii) immunization with gel-purified P145, and (iii) immunization with a P145-expressing transformant of a laboratory H. influenzae strain expressing this protein and absorption of the antiserum with the laboratory H. influenzae strain. These antisera had low antilipooligosaccharide antibody titers, were reactive only with P145, and had bactericidal activity in vitro. Following passive immunization, these antisera partially protected infant rats from bacteremia resulting from intraperitoneal challenge with bacteria. As assessed by immunoblotting, pooled adult human sera contained antibodies reactive with P145. Antibody to P145 may contribute to protection against Brazilian purpuric fever.

  2. 衍生自人ⅡA型磷脂酶A2碳末端的多肽C-26杀菌作用研究%Study on Bactericidal Activity of the Polypeptide C-26 Derived from C-terminal of Human Group Ⅱ A Phospholipase A2

    Institute of Scientific and Technical Information of China (English)

    何睿林; 梁宁生

    2011-01-01

    OBJECTIVE: To observe the bactericidal activity of the polypeptide C-26 which derives from C-terminal of human group H A phospholipase A2(group II A PLA2). METHODS: According to C-terminal 26 amino acid residues sequence of human group HA phospholipase A2, a piece of polypeptide C-26 had been synthesized. 6 kinds of bacterial strains (Staphylococcus aure-us, Bacillus subtilis, Bacillus anthrax, Escherichia coli, Bacillus proteus and Bacillus pyocyaneus) were incubated with different concentration of polypeptide C-26 at 37 ℃ for 2 h in a water bath respectively. After incubated for 18~24 hours in the thermostat-ed container at 37 t, the colony formed unit was counted and the bactericidal rates of polypeptide C-26 were calculated. RESULTS: The polypeptide C-26 possessed potent bactericidal activity to the gram-positive(G') bacteria, such as Staphylococcus aure-us, Bacillus subtilis, Bacillus anthrax, the concentration of polypeptide C-26 against 99% bacteria ranged 250~l 000 mg·L-1; it possessed weak bactericidal activity to the gram-negative (G-) bacteria, such as Escherichia coli, Bacillus proteus,Bacillus pyocyaneus. The bactericidal rate of polypeptide C-26 with the concentration of 500 mg·L-1 were 41%~52%. CONCLUSION: The polypeptide C-26 which derives from C-terminal of human group ⅡA PLA2 possesses bactericidal activity, it is speculated that the polypeptide might have similar bactericidal mechanism as human group ⅡA PLA2 and the other antibacterial peptides.%目的:考察衍生自人ⅡA型磷脂酶A2(ⅡA型PLA2)碳(C)末端的多肽C-26对不同细菌的体外杀菌作用.方法:根据人ⅡA型PLA2 C末端26个氨基酸残基的顺序,合成多肽C-26.采用琼脂铺板计数法,将不同浓度的多肽C-26分别与6种细菌(金黄色葡萄球菌、炭疽杆菌、枯草杆菌、大肠杆菌、变形杆菌和绿脓杆菌)在37℃孵育2 h,然后铺板并置于37℃恒温箱培养18~24 h,记录每一琼脂板上的菌落形

  3. Evaluación de la Actividad Bactericida de Bacterias Ácido Lácticas Aisladas en Calostro de Cerdas Frente a Salmonella typhimurium / Bactericidal Evaluation of Lactic Acid Bacteria Isolated in Sow Colostrum Against Salmonella tiphymurium

    Directory of Open Access Journals (Sweden)

    Juliana María Vélez Zea

    2014-12-01

    Full Text Available Resumen. En los sistemas de crianza intensiva especialmenteen cerdos, la resistencia antimicrobiana de algunas bacteriaspatógenas, se ha convertido en un problema mundial, tantopara los productores como para los consumidores. El uso demicroorganismos probióticos aislados de calostro de cerda criadasen sistemas intensivos han demostrado eficacia en la inhibicióndel crecimiento de algunos patógenos entéricos. Se eligierondos cepas denominadas como BAL1 y BAL3, a las cuales se lesevaluó el potencial bactericida de los extractos bacterianos sobreel patógeno Salmonella thipymurium, por el método de difusiónen pozos en agar Mueller Hinton. Los extractos se obtuvieronajustando el inóculo a 0,5 McF en caldo MRS, centrifugados a6.000 rpm por 5 minutos y filtrados con membrana de 0,2 μm.Ambos extractos mostraron tener un alto potencial bactericidafrente a esta bacteria, con promedios de halo de inhibición de 11mm in vitro.  / Abstract. In intensive farming systems especially in pigs, theantimicrobial resistance of some pathogenic bacteria has becomea global problem, both for producers and consumers. The use ofprobiotic microorganisms isolated of sow colostrum in intensivefarms have demonstrated the ability to inhibit the growth of someenteric pathogens. Two of these strains named as BAL1 and BAL3were chosen for evaluate the bactericidal potential of their extractsagainst the pathogen Salmonella typhimurium. The well diffusionmethod, in Mueller Hinton agar was used. The BAL extractswere obtained, adjusted the BAL inoculum in MRS broth at 0.5MacFarland, centrifuged at 6,000 rpm for 5 minutes and filteredwith a 0.2 um membrane. Both extracts demonstrated to havebactericidal activity against this bacterium with mean inhibitionhalos of 11 mm in vitro.

  4. Synergistic bactericidal effects of low-frequency ultrasound and antibiotics against bacteria%低频超声与抗菌药物协同增效研究进展

    Institute of Scientific and Technical Information of China (English)

    刘旭; 蔡芸; 白艳; 朱亚萍; 王睿

    2013-01-01

    It is difficult to eradicate bacteria completely with single antibiotic because of serious drug resistance. The combination of low-frequency ultrasound technology and antibiotics could enhance the bactericidal or bacteriostatic effect of antibiotics on both planktonic bacteria and bacterial biofilm. The primary mechanism may be cavitation effect. Currently, low-frequency ultrasound technology has been applied to local infection treatment. As a non-invasive and targeted therapy, low-frequency ultrasound technology has great potential use in clinic. In addition, the low-frequency ultrasound technology has advantage on gene transfection and inhibition of bacterial resistance by changing the genes.%  细菌耐药日益严重,单一抗菌药物难以完全杀灭耐药菌。应用低频超声技术联合抗菌药物,无论是对于浮游态菌还是生物被膜态菌,都能增强抗菌药物的杀菌或抑菌作用。其机制主要为空化效应。目前,低频超声技术已探索性应用于人体局部感染治疗中。作为一种可靶向治疗的非侵入性疗法,低频超声具有很大的临床应用潜能。此外,低频超声技术在基因转染上具有优势,并可通过改变基因来影响细菌耐药性。

  5. 压裂用瓜胶用杀菌剂筛选与作用效果评价%Screening and Evaluation of Bactericide for Guar Gum using in Fracturing Fluid

    Institute of Scientific and Technical Information of China (English)

    薛东圆; 张洁; 秦芳玲; 汤颖; 谢璇

    2015-01-01

    油田压裂液稠化剂主要是植物胶,由于受到微生物的降解,天然植物胶极易发生降解、解黏和发霉等问题.本研究通过对4类杀菌剂及复配杀菌剂对瓜胶原液黏度保持作用的对比,评价了其杀菌效果.结果表明,0.5%的丙烯醛、0.5%脲醛、0.5% 1,4-对苯二酚、0.1%水解植物酚、0.9﹪生理盐水及0.9% NaCl与0.5%丙烯醛的复配杀菌剂具有较显著的抑制瓜胶降解的作用,在杀菌处理4d时,0.5%瓜胶原液的黏度降低率均低于16%.%Plant gum was the main viscosifier in oil field fracturing fluid. The plant gum degraded and mildewed easily, and the vis-cosity of its solution decreased correspondingly. In this work, the efficiency of the bactericides was evaluated by the viscosity main-taining. The results showed that 0.5% acrolein, 0.5% urea formaldehyde, 0.5% 1,4-hydroquinone, hydrolyzed plant phenol, 0.9% saline and 0.9% NaCl & 0.5% acrolein could inhibit the degradation of guar gum, and the viscosity of 0.5% guar gum solution only decreased by less than 16% within 4d.

  6. [Antibiotic therapy against acute tonsillopharyngitis in children due to group A beta-hemolytic streptococci: comparison of clinical efficacy, the bactericidal effects, and effects on oral flora between cefditoren pivoxil for 5 days and amoxicillin for 10 days].

    Science.gov (United States)

    Tsumura, Naoki; Nagai, Kensuke; Hidaka, Hidenobu; Otsu, Yasushi; Tanaka, Yuhei; Ikezawa, Shigeru; Honma, Shinichi; Shindo, Shizuo; Ubukata, Kimiko

    2011-06-01

    We compared the clinical efficacy, the bactericidal effects, effect on the oral microbial flora, and adverse reactions between cefditoren pivoxil (CDTR-PI) for 5 days and amoxicillin (AMPC) for 10 days in children with acute group A beta-hemolytic streptococci (GAS) tonsillopharyngitis, and simultaneously examined the emm genotype and drug susceptibility of the isolated GAS. The results showed that the clinical efficacy was 100% for CDTR-PI and 97.9% for AMPC, with no difference between the two groups, and the bacterial elimination rate was 100% in both groups. No serious adverse event was noted in either group. On the other hand, concerning changes in the oral microbial flora between before and after treatment, the amount of bacteria showed no change in the CDTR-PI group (p = 0.5761) but clearly decreased in the AMPC group (p = 0.0049). This indicates that CDTR-PI does not disturb the oral microbial flora compared with AMPC. Also, the emm types determined in the 112 GAS strains isolated in this study were similar to those that have recently been isolated frequently in Japan. Concerning the drug resistance, none of the isolates showed resistance to beta-lactam antibiotics, but 45% of them were resistant to macrolides. The advantages of short-term treatment are considered to include a lower cost, improvement in drug compliance, decrease in the frequency of the occurrence of adverse reactions, decrease in the frequency of the appearance of drug-resistant strains, and alleviation of the psychological burden of patients and their parents. For these reasons, we conclude that CDTR-PI for 5 days is a useful option for the treatment of acute GAS tonsillopharyngitis in children.

  7. Bactericidal Effect of Ultra-high Pressure on the Clarified Apple Juice%超高压对澄清苹果汁杀菌效果的研究

    Institute of Scientific and Technical Information of China (English)

    杨晓苗; 阮美娟

    2012-01-01

    The relations between the number of microorganisms and processing pressure and holding time in UHP treatment to clarified apple juice were investigated. The numbers of total bacteria, mold and yeast in clarified apple juice were measured after pressure treatment at 100-500 MPa for 5-30 min. The results showed that the bactericidal effect was improved with the increase of pressure level and pressure-holding time. Mold and yeast were more sensitive to high hydrostatic pressure. The linear model was used to fit the survival curve. The correlation coefficients (R2) were more than 0.950 determined at five pressure levels, which proved that linear model was suitable for the kinetic analysis of bacterial inactivation.%为研究澄清苹果汁超高压处理与微生物数量之间的关系,考察了菌落总数、霉菌和酵母菌数在压力100~500 MPa、保压时间5~30 min条件下的变化.结果表明:随着压力的升高和时间的延长,杀菌效果增强;霉菌和酵母菌对压力较为敏感.对不同处理压力下苹果汁杀菌效果进行动力学分析,应用线性模型,绘制杀菌曲线,在5个压力水平下,相关系数R2均大于0.950,证明线性拟合效果良好.

  8. Dissolution and Elimination Characteristics of Ozone in Water and Its Bactericidal Effect on Penicillium expansum%臭氧在水中的溶解和消除特性及其难苹果青霉的杀菌效果

    Institute of Scientific and Technical Information of China (English)

    乔彩云; 李建科; 李梦颖; 马倩倩; 张纽枝; 赵彦华; 马丽红

    2012-01-01

    研究臭氧在水中的溶解和消除特性及不同质量浓度臭氧水对致使苹果腐败的苹果青霉的杀菌效果。结果表明:臭氧投加量会影响臭氧的溶解性,在水温12~14℃条件下,不同体积吸收液的臭氧质量浓度在通气15min时均趋于最优,且臭氧水在12~14℃、29~30℃环境下的半衰期分别为23min和16min;臭氧对苹果青霉有杀灭效果,用质量浓度1.2mg/L的臭氧水对苹果青霉作用5min后的杀菌率达93.00%。%In this paper, the dissolution and elimination characteristics of ozone in water and its bactericidal effect at various concentrations on Penicillium expansum in apples are described. We found that ozone-blowing time could affect the solubility of ozone. At 12-14 ℃, optimal ozone concentration was achieved after blowing for 15 min. The half-life time of ozone water was 23 min at 12-14 ℃ and 16 min at 29-30 ℃. In addition, ozone water had an obvious bactericidal effect on Penicillium expansum. Treatment of Penicillium expansum for 5 min with 1.2 mg/L ozone water provided a bactericidal rate of 93.00%.

  9. Hybrid organic/inorganic reverse osmosis (RO) membrane for bactericidal anti-fouling. 1. Preparation and characterization of TiO2 nanoparticle self-assembled aromatic polyamide thin-film-composite (TFC) membrane.

    Science.gov (United States)

    Kwak, S Y; Kim, S H; Kim, S S

    2001-06-01

    Hybrid organic/inorganic reverse osmosis (RO) membranes composed of aromatic polyamide thin films underneath titanium dioxide (TiO2) nanosized particles have been fabricated by a self-assembly process, aiming at breakthrough of biofouling problems. First, positively charged particles of the colloidal TiO2 were synthesized by a sol-gel process, and the diameter of the resulting particles in acidic aqueous solution was estimated to be approximately 2 nm by analyzing the UV-visible absorption characteristics with a quantum mechanical model developed by Brus. Transmission electron microscopy (TEM) further confirmed the formation of the quantum-sized TiO2 particles (approximately 10 nm or less). The TiO2 particles appeared to exist in the crystallographic form of anatase as observed with the X-ray diffraction (XRD) pattern in comparison with those of commercial 100% rutile and commercial 70:30% anatase-to-rutile mixture. The hybrid thin-film-composite (TFC) aromatic polyamide membranes were prepared by self-assembly of the TiO2 nanoparticles on the polymer chains with COOH groups along the surface. They showed improved RO performance in which the water flux even increased, though slightly. Field-emission scanning electron microscopy (FESEM) exhibited the TiO2 nanoparticles well adsorbed onto the surface. X-ray photoelectron spectroscopy (XPS) demonstrated quantitatively that a considerable amount of the adsorbed particles were tightly self-assembled at the expense of the initial loss of those that were loosely bound, and became stabilized even after exposure to the various washing and harsh RO operating conditions. The antibacterial fouling potential of the TiO2 hybrid membrane was examined and verified by measuring the viable numbers and determining the survival ratios of the Escherichia coli (E. coli) as a model bacterium, both with and without UV light illumination. The photocatalytic bactericidal efficiency was remarkably higher for the TiO2 hybrid membrane under UV

  10. 碳纤维复合涂层在高压脉冲电场下的杀菌性能研究%Research on Bactericidal Properties of Carbon Fiber Composite Coatings in High-voltage Pulse Electric Field

    Institute of Scientific and Technical Information of China (English)

    杨鹏鹏; 吴进怡; 柴柯; 林海强; 宋春蕾

    2015-01-01

    ABSTRACT:Objective To explore the inhibition effects and mechanism of high-voltage pulsed electric field ( HPEF) in marine environment on microbial fouling. Methods Carbon fiber / epoxy composite anti-corrosion coating was prepared by brushing meth-od, and the effects of the carbon fiber length and content on the dielectric properties and surface energy of the composite coating as well as the bactericidal performance of the carbon fiber composite coating in high-voltage pulsed electric field. Results The results showed that the carbon fiber length and content were the main factors affecting the dielectric properties of the composite coating un-der high frequency. With the increase of electric field intensity and frequency within the set range, the sterilization rate of the coat-ing obviously increased, while with the increase of duty cycle, the sterilization rate of the coating first increased and then decreased and finally tended to be stable. When the duty cycle was 0. 5, the maximum sterilization rate of 99. 8% was reached. Conclusion The composite coating with a doping content of 0. 1% 5 mm carbon fiber had excellent dielectric properties. High-voltage pulsed e-lectric field had a good killing effect on bacteria and the sterilization rate of the coating could reach 99. 97%.%目的:研究海洋环境下高压脉冲电场对微生物污损的抑制效果和机理。方法采用刷涂法制备碳纤维/环氧防腐涂料复合涂层,研究碳纤维长度和含量对复合涂层的介电性能和表面能的影响以及碳纤维复合涂层在高压脉冲电场作用下的杀菌性能。结果高频电场下,碳纤维长度和含量是影响复合涂层介电性能的主要因素,随着电场强度、频率在设定范围内增加,涂层的杀菌率显著增大;而随占空比的增大,涂层的杀菌率呈先增后减最后趋于平缓的趋势,占空比为0.5时涂层的杀菌率最高达99.8%。结论掺杂0.1%(质量分数)5 mm碳纤维的

  11. 杀菌性/通透性增加蛋白模拟肽对内毒素休克模型家兔动脉血压影响的研究%Effects of bactericidal/permeability increasing protein modeling peptide on arterial blood pressure of endotoxin-shocked rabbits

    Institute of Scientific and Technical Information of China (English)

    卫国; 吕根法; 郭毅斌; 郑江

    2003-01-01

    杀菌性/通透性增加蛋白(Bactericidal/permeability increasing protein,BPI)是一种存在于人及哺乳动物中性粒细胞嗜天青颗粒中带正电荷的蛋白质,具有较强的杀灭革兰阴性菌(Gramnegative bacteria,GNB)及中和内毒素(Lipopolysaeeharide,LPS)的能力,对严重GNB感染具有一定疗效。通过多年的研究,本室采用计算机分子模拟技术设计合成了BP1模拟肽,本研究拟通过观察BP1模拟肽对平均动脉压、脉压的影响,以了解其抗内毒素休克功效。

  12. In vitro assessment of the bactericidal effect of low-power arsenium-gallium (AsGa laser treatment Avaliação in vitro da ação bactericida do laser de baixa potência (AsGa

    Directory of Open Access Journals (Sweden)

    Adilvania Ferreira da Costa

    2012-08-01

    Full Text Available The objective of the present study was to perform an in vitro evaluation of the bactericidal action of a low-power arsenium-gallium (AsGa laser at a wavelength of 904nm and energy density of 6 J/cm². Ten petri dishes were seeded with Pseudomonas aeruginosa and another ten with Staphylococcus aureus. The dishes were then randomly divided into four groups with five plates in each group. Two groups were treated with AsGa laser once a day for 5 days, while the other two groups received no treatment. No halo of growth inhibition was found in any of the groups. It was therefore concluded that laser treatment (AsGa, 904nm, 6J/cm² had no bactericidal effect.Verificar, in vitro, o efeito bactericida do laser de baixa potência, AsGa, 904nm, na dose 6 J/cm2. Foram semeadas 10 placas de Petri com a bactéria Pseudomonas aeruginosa e 10 placas de Petri com Staphylococcus aureus. Aleatoriamente, foram divididas em quatro grupos (5 placas cada: dois grupos foram tratados com o laser AsGa a cada 24 horas, durante cinco dias, e dois grupos não receberam tratamento. Em todos os grupos, não foi observado qualquer halo de inibição do crescimento. Assim, concluiuse que a terapia a laser (AsGa, 904nm, 6 J/cm² não produziu efeito bactericida.

  13. 湖北省某县健康人群C群流行性脑脊髓膜炎检测和评价%Evaluation on the detection of antibodies against Serogroup C Neisseria meningitides by serum bactericidal assay in healthy population of Hubei Province

    Institute of Scientific and Technical Information of China (English)

    吕静; 杨红梅; 徐丽; 朱兵清; 江永忠; 李国明; 程均福; 尹遵栋

    2012-01-01

    目的 了解湖北省某县健康人群中C群脑膜炎奈瑟菌(Nm)抗体的保护性水平.方法 随机抽取湖北省7个年龄组共189份健康人群血清样品,采用血清杀菌试验方法,以C群脑膜炎奈瑟菌疫苗株(C11)作为靶菌,检测和分析湖北省不同年龄组健康人群对C群Nm的血清杀菌力水平.并对检测结果进行统计分析.结果 189份健康人群血清对C群Nm的杀菌抗体阳性率为44.44%,几何平均滴度(GMT)为1:6.37,人群保护率(抗体滴度≥1:8)为38.10%,其中,1~2岁年龄组GMT最低(1:2.96),阳性率为33.33%,人群保护率为23.33%,15 ~ 19岁年龄组GMT最高(1:10.80),阳性率为56.67%,人群保护率为50.00%.6岁以下儿童GMT为(1:4.78),阳性率为39.29%,保护率为33.03%,低于较高年龄组. 结论 湖北省6岁以下年龄组健康人群对C群Nm血清杀菌力水平较低;实施扩大免疫规划后,小年龄儿童仍需要采取措施提高C群流脑抗体水平;继续进行免疫效果监测是非常必要的.%Objective To understand the bactericidal antibody level against Neisseria meningitidis serogroup C in healthy population of Hubei province. Methods 189 serum samples were randomly collected from seven age groups by serum bactericidal to detect the antibody level against Neisseria meningitidis serogroup C with vaccine strain (C11 )as target bacteria for SBA. The results were analyzed by software SAS 9.1. Results Totally 44.44% of 189 serum samples were positive to Cll (titer 5=1:2)with the Geometric Mean Titer (GMT)(1:6.37 and the protective rate of 38.10% and titer 3=1:8. The GMT in age group of 1 to 2 years was lowest (l:2.96)with the positive rate of 33.33% and protective rate of 23.33% . The GMT in age group of 15 to 19 years was the highest(l: 10.80),with the positive rate of 56.67% and protective rate of 50.00%. The GMT in children younger than 6 years wasl:4.78 with positive rale of 39.29% and protective rate of 33.03%,lower than other age

  14. The Evaluation of Teat Dipping Coating Agent for Cow Mastitis Pathogens Bactericidal and Bacteriostatic Test in Vitro%聚维酮碘乳头药浴涂膜剂对奶牛乳房炎致病菌体外抑菌效果评价

    Institute of Scientific and Technical Information of China (English)

    周庆民; 冯万宇; 徐馨; 侯美如; 黄健

    2015-01-01

    This study aims to understand in vitro bacteriostasis effectiveness(MIC and MBC)of the teat dipping coating agent on major pathogens(Escherichia coli, Staphylococcus aureus, Streptococcus agalactiaeand Streptococcus dysgalactiae)andprovideacertainofscientiifcevidence.Utilizing10timesmicrodilutionmethod, we determine in vitro effectiveness of the teat dipping coating agent on clinical isolates strain of the major cows mastitis. In order to compare bacteriostasis effectiveness of the teat dipping coating agent and antibiotics,we design the control group-ceftiofur and penicillin. The results show that in vitro the agent has signiifcant bacteriostasis effects on four major pathogens of cow mastitis, and the bactericidal and bacteriostatic concentration is lower than ceftiofur and penicillin.%本试验采用10倍稀释法进行了乳头药浴涂膜剂对奶牛乳房炎临床分离菌株(大肠杆菌、金黄色葡萄球菌、无乳链球菌及停乳链球菌)的体外抑菌效果测定。结果显示,乳头药浴涂膜剂对四种致病菌有良好的体外抑菌和杀菌作用,其抑杀菌浓度低于头孢噻呋和青霉素。

  15. Effects of interleukin-1O on phagocytosis and bactericidal activity of neutrophils in mouse model%白细胞介素-10对小鼠中性粒细胞吞噬和杀菌活性的影响

    Institute of Scientific and Technical Information of China (English)

    赵修春; 徐凤珍; 李柏青

    2011-01-01

    Objective:To investigate the effects of inteluekin-10( IL-10 ) on the neutrophil phagocytosis and bactericidal activity in mouse model. Methods:Whole blood of mice was pretreated with IL-10 at different concentrations, ranged from 1 pg to 100 ng/ml for 2 hours at 37 ℃, and then incubated with FITC labeled E. coli at 37 ℃ for 15 minutes. After lysing red blood cells the neutrophil phagocytosis was measured by flow cytometry. In the bactericidal assay,whole blood of mice pretreated with IL-10( 0.1 and 1 ng/ml )for 2 hours at 37 ℃ was incubated with E. coli in water bath at 37 ℃ for 1 hour, and then cultured on agar plates. The number of colonies was counted and the inhibitory effect of IL-10 on killing activity was calculated. Results:The reduced rates of phagocytosis was ( 15.87 ± 14.25 )% only in the group that pretreated with IL-10 at 1 ng/ml,but with no significance( P >0.05 ). The relative rates of bactericidal activity of neutrophil in the groups of IL-10 at 0.1 ng/ml and 1 ng/ml were significanty reduced( 39.59 ± 37.36 )% and ( 42.28 ± 22.24 )% ( P < 0.05 ), respectively. Conclusions: IL-10 slightly decreases the phagocytosis of the neutrophils, but potently suppresses the bactericidal activity of neutrophils. IL-10 is capabling of down-regulating non-specific immunity.%目的:探讨白细胞介素-10(IL-10)对中性粒细胞(PMN)吞噬和杀菌活性的影响,以了解IL-10对非特异性免疫的作用机制.方法:小鼠麻醉后从眼球取血,与不同浓度IL-10在37 ℃水浴中作用2 h,然后加FITC标记大肠埃希菌,置37 ℃水浴中15 min,溶血剂去除红细胞,流式细胞仪检测各IL-10浓度组PMN的吞噬率.小鼠麻醉后局部消毒,摘眼球,无菌方法取血.与不同浓度IL-10 在37 ℃下作用2 h,然后加大肠埃希菌置37 ℃水浴1 h,同时设PMN杀菌0 min组、无IL-10的PMN杀菌对照组,各组样品作适当稀释后接种琼脂平板,最后观察各组菌落数,与对照组比较,计算IL-10对

  16. 维生素C降低大蒜素联合美罗培南对耐碳青霉烯类抗生素的鲍曼不动杆菌的杀菌作用%Vitamin C decreases bactericidal effect of allicin combined with meropenem on carbapenem-resistant Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    王梅; 姜梅杰; 李玉臣; 于亮

    2012-01-01

    investigate the impact of vitamin C on bactericidal effect of allicin combined with meropenem on carbapenem- resistant Acinetobacter baumannii in vitro.Method Six carbapenemase-producing multiple drug-resistant Acinetobacter baumannii strains were identified by EDTA-Na2 paper composite method and modified three-dimensional experimental approach.The minimal inhibitory concentration (MIC) of allicin and meropenem was determined for calculation of combination inhibition fraction (FIC) index for combined therapy using MH broth.The bacterial inhibitory rates of allicin,meropenem,allicin combined with meropenem and allicin combined with vitamin C (0.25 g/L) in various concentrations were detected via microplate bio-detection assay.After adding allicin (32,64 mg/L and 128mg/L respectively) and the combination of allicin and 0.25 g/L vitamin C,the variations in glutathione,antisuperoxide anion free radicals and total thiol group levels within the bacteria were measured.Results All the six carbapenem-resistant Acinetobacter baumannii strains were found to produce carbapenemase.These six strains yielded MIC of 512 mg/L for allicin and 128 mg/L for meropenem.Allicin combined with meropenem was associated with FIG of 0.25.Various concentrations of allicin combined with meropenem resulted in a considerably higher bacterial inhibitory rates than either drug alone.By contrast,0.25 g/Lvitamin C combined with various concentrations of allicin resulted in marked reduction of bacterial inhibitory rates (all P<0.05) as compared with equal concentration of allicin alone.In addition,lower glutathione,antisuperoxide anion and total thiol group levels (all P<0.05) were revealed in bacteria treated with various concentrations of allicin (32,64 mg/L and 128 mg/L) as compared with control group.Increased allicin concentration was associated with gradual decline in bacterial glutathione,anti-superoxide anion and total thiol group levels (all P<0.05).The 128 mg/L allicin-treated bacteria exhibited

  17. Bactericidal Efficiency of Silver Nanoparticles Synthesized from Annona squamosa

    Science.gov (United States)

    Jayavardhanan, R.; Nanda, Anima

    2016-09-01

    Nanotechnology is described as an emerging technology that not only holds promise for society, but also is capable of providing novel approaches to overcome our common problems. The present study focused on the synthesis of silver nanoparticles using the metabolites of Annona squamosa seeds. The biological reduction procedure proposed in this method was considered as better one compared to chemical mediated reduction methods. The advantages include nontoxic to the environment, less energy consuming and highly suitable for further biological applications. The seeds were separated from the fruit pulp, grinded into powder and dissolved in distilled water. The suspension was used as reducing agent and treated with silver nitrate at the concentration of 1mM. The reduction reaction was continuously monitored by UV-visible photo spectrometer. Further the samples were subjected to AFM, SEM and XRD analysis for the confirmation of their size, structure, agglomerations and the arrangements of crystals. Finally the antibacterial properties of nanoparticles were tested against clinically important pathogenic microorganisms using disc diffusion method and compared with the activities of standard antibiotics. The combinational effects of nanoparticles with commercial antibiotics also were tested by the same method.

  18. Silver nanoparticles are broad-spectrum bactericidal and virucidal compounds

    Directory of Open Access Journals (Sweden)

    Ixtepan-Turrent Liliana

    2011-08-01

    Full Text Available Abstract The advance in nanotechnology has enabled us to utilize particles in the size of the nanoscale. This has created new therapeutic horizons, and in the case of silver, the currently available data only reveals the surface of the potential benefits and the wide range of applications. Interactions between viral biomolecules and silver nanoparticles suggest that the use of nanosystems may contribute importantly for the enhancement of current prevention of infection and antiviral therapies. Recently, it has been suggested that silver nanoparticles (AgNPs bind with external membrane of lipid enveloped virus to prevent the infection. Nevertheless, the interaction of AgNPs with viruses is a largely unexplored field. AgNPs has been studied particularly on HIV where it was demonstrated the mechanism of antiviral action of the nanoparticles as well as the inhibition the transmission of HIV-1 infection in human cervix organ culture. This review discusses recent advances in the understanding of the biocidal mechanisms of action of silver Nanoparticles.

  19. Ungeremine and Its hemisynthesized analogues as bactericides against Flavobacterium columnare.

    Science.gov (United States)

    Schrader, Kevin K; Avolio, Fabiana; Andolfi, Anna; Cimmino, Alessio; Evidente, Antonio

    2013-02-13

    The Gram-negative bacterium Flavobacterium columnare is the cause of columnaris disease, which can occur in channel catfish ( Ictalurus punctatus ). In a previous study, the betaine-type alkaloid ungeremine, 1, obtained from Pancratium maritimum L. was found to have strong antibacterial activity against F. columnare. In this study, analogues of 1 were evaluated using a rapid bioassay for activity against F. columnare to determine if the analogues might provide greater antibacterial activity and to determine structure-activity relationships of the test compounds. Several ungeremine analogues were prepared by hydrochlorination of the alkaloid and by selenium dioxide oxidation of both lycorine, 7, and pseudolycorine, 8, which yielded the isomer of ungeremine, 3, and zefbetaine, 4, respectively. The treatment of lycorine with phosphorus oxychloride allowed the synthesis of an anhydrolycorine lactam, 5, showing, with respect to 1, the deoxygenation and oxygenation of C-2 and C-7 of the C and B rings, respectively. The results of the structure-activity relationship studies showed that the aromatization of the C ring and the oxidation to an azomethine group of C-7 of the B ring are structural features important for antibacterial activity. In addition, the position of the oxygenation of the C ring as well as the presence of the 1,3-dioxole ring joined to the A ring of the pyrrolo[de]phenanthridine skeleton also plays a significant role in imparting antibacterial activity. On the basis of 24-h 50% inhibition concentration (IC(50)) results, ungeremine hydrochloride, 2, was similar in toxicity to 1, whereas 5 had the lowest activity. Analogue 2 is soluble in water, which may provide the benefit for use as an effective feed additive or therapeutant compared to ungeremine.

  20. Sporicidal/bactericidal textiles via the chlorination of silk.

    Science.gov (United States)

    Dickerson, Matthew B; Lyon, Wanda; Gruner, William E; Mirau, Peter A; Slocik, Joseph M; Naik, Rajesh R

    2012-03-01

    Bacterial spores, such as those of the Bacillus genus, are extremely resilient, being able to germinate into metabolically active cells after withstanding harsh environmental conditions or aggressive chemical treatments. The toughness of the bacterial spore in combination with the use of spores, such as those of Bacillus anthracis, as a biological warfare agent necessitates the development of new antimicrobial textiles. In this work, a route to the production of fabrics that kill bacterial spores and cells within minutes of exposure is described. Utilizing this facile process, unmodified silk cloth is reacted with a diluted bleach solution, rinsed with water, and dried. The chlorination of silk was explored under basic (pH 11) and slightly acidic (pH 5) conditions. Chloramine-silk textiles prepared in acidified bleach solutions were found to have superior breaking strength and higher oxidative Cl contents than those prepared under caustic conditions. Silk cloth chlorinated for ≥1 h at pH 5 was determined to induce >99.99996% reduction in the colony forming units of Escherichia coli, as well as Bacillus thuringiensis Al Hakam (B. anthracis simulant) spores and cells within 10 min of contact. The processing conditions presented for silk fabric in this study are highly expeditionary, allowing for the on-site production of protein-based antimicrobial materials from a variety of agriculturally produced feed-stocks.

  1. Micrococcin P1-A bactericidal thiopeptide active against Mycobacterium tuberculosis

    OpenAIRE

    Degiacomi, Giulia; Personne, Yoann; Mondesert, Guillaume; Ge, Xueliang; Mandava, Chandra Sekhar; Hartkoorn, Ruben C.; Boldrin, Francesca; Goel, Pavitra; Peisker, Kristin; Benjak, Andrej; Barrio, Maria Belen; Ventura, Marcello; Amanda C Brown; Leblanc, Veronique; Bauer, Armin

    2016-01-01

    The lack of proper treatment for serious infectious diseases due to the emergence of multidrug resistance reinforces the need for the discovery of novel antibiotics. This is particularly true for tuberculosis (TB) for which 3.7% of new cases and 20% of previously treated cases are estimated to be caused by multi-drug resistant strains. In addition, in the case of TB, which claimed 1.5 million lives in 2014, the treatment of the least complicated, drug sensitive cases is lengthy and disagreeab...

  2. Ceftobiprole: in-vivo profile of a bactericidal cephalosporin.

    Science.gov (United States)

    Chambers, H F

    2006-04-01

    Resistance to antimicrobials is a significant and growing problem, limiting treatment options, especially for serious Gram-positive infections. Ceftobiprole is a novel broad-spectrum cephalosporin that is active in vitro against streptococci and staphylococci, including penicillin-resistant strains of pneumococci and methicillin-resistant Staphylococcus aureus (MRSA). It maintains the activity of extended-spectrum cephalosporins against Gram-negative bacteria, including Enterobacteriaceae. The in-vivo activity of ceftobiprole has been demonstrated in mouse sepsis and subcutaneous abscess models of infection. Its activity also has been examined in several discriminative models of infection that mimic specific diseases in humans and permit testing of antimicrobial activity under a variety of defined pharmacokinetic conditions. These include experimental pneumonia in mice, a tissue cage model of foreign body infection in rats, and endocarditis models in rats and rabbits. In these models, ceftobiprole exhibits activity equivalent or superior to that of comparators against MRSA, including vancomycin-intermediate strains. These models also confirm the in-vivo activity of ceftobiprole against Gram-negative bacteria that are susceptible in vitro. The results from animal models support the evaluation of the clinical efficacy of ceftobiprole in humans and also predict clinical efficacy in the empirical treatment of severe infections. The broad spectrum of activity may allow ceftobiprole to be used as monotherapy for serious hospital-acquired infections where combination therapy would otherwise be required.

  3. Use of titanium-based materials as bactericides

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, David T; Elvington, Mark C; Wataha, John; Chung, Whasun O; Rutherford, R. Bruce; Chan, Daniel C

    2013-10-01

    Compositions containing metal ions bound into a titanate are described which have demonstrated an ability to suppress bacterial growth of a number of organisms associated with periodontal disease and caries.

  4. Nanocharacterization and bactericidal performance of silver modified titania photocatalyst.

    Science.gov (United States)

    Pan, Xubin; Medina-Ramirez, Iliana; Mernaugh, Ray; Liu, Jingbo

    2010-05-01

    An environmental-friendly procedure for manufacturing silver (Ag) and titania (TiO(2)) nanocomposites in an aqueous solution is presented. This green synthetic approach results in the successful production of nanomaterials with high dispersion and crystallinity. The colloidal suspensions of the nanocomposites composed of metal and ceramic (Ag-TiO(2)) were found to be extremely stable over a prolonged time period. Morphologically, nanocomposites were found to be composed of near-spherical particles that were highly crystalline. The nanocomposites were mono-dispersed with particles varying in size from 20 to 50nm, depending upon nanocomposite solution pH. Indexed metallic nanoscale silver exhibited a face-centered cubic (fcc) crystalline phase structure. Nanocomposite elemental composition studies indicated that the molar ratio of Ag and Ti was approximately 1-20. The binding energies and energy differences of Ag, Ti and O were well-indexed with their associated standard spectra. Nanocomposite optical absorption properties were consistent with noble metal nanoparticles. The zetapotential for the nanocomposites was higher at acidic pH and exhibited an absolute negative charge that apparently inhibited particle agglomeration. Escherichia coli (E. coli), a Gram-negative model microorganism was effectively inactivated using the nanocomposites under visible light at ambient temperature and pressure. The 'green chemistry' derived Ag-TiO(2) composites are applicable for the removal of biological impurities from drinking and underground water supplies. The results of the study indicated that nanocomposites could be specifically designed to prevent growth of bacteria in water.

  5. 大鼠中耳上皮细胞形态学变化与杀菌-通透性增强蛋白的关系%Relation between the morphologic change of rat middle ear epithelium and bactericidal/permeability-increasing protein

    Institute of Scientific and Technical Information of China (English)

    祝威; 汪欣; 崔香艳; 杜宝东

    2004-01-01

    BACKGROUND: The recovery of middle ear morphology is an important index of improvement of chronic secretory otitis media. Looking for effective medicine to neutralize lipopolysaccharide and relieving the virulence of lipopolysaccharide to middle ear mucosa have drawn more attention.OBJECTIVE: To study the effect that bactericidal/permeability-increasing protein(BPI) neutralizing lipopolysaccharide to inhibit morphologic changes of the middle ear epithelium due to lipopolysaccharide.DESIGN: A nonrandomized controlled experimental study.SETTING and PARTICIPANTS: The setting is in Jilin University. Participants were 10 purebred Wistar rats in clean grade, weighing 200 -250 g, purchased from Center for Experimental Animals, Jilin University, and feeding condition was at 20 - 25℃, humidity of 60% - 70%.INTERVENTIONS: The middle ear epithelial cells were obtained from 10Wistar rats and distributed into 24-well tissue culture plate coated with poly-lysine. These epithelial cells were cultured for 7 days, and then divided into 3 groups: Untreated group was cultured without lipopolysaccharide and BPI in the culture medium; Lipopolysaccharide group was cultured with 1 μg/L lipopolysaccharide in the culture medium; BPI group was cultured with 1 μg/L lipopolysaccharide for 7 days, and then with added 1 mg/L BPI in the culture medium.MAIN OUTCOME MEASURES: The morphologic changes of the middle ear epithelial cells were observed under light microscope after 4 weeks.RESULTS: Compared to untreated group, lipopolysaccharide group showed that many cells became greater and swollen, and the number of them was increasing, the phenomena of cell breakage were observed in few areas 1week later. At 2 weeks, cells became much greater and swollen, and the number of broken and dead cells was obviously increased. Moreover, an increase in secretory cells and a decrease in ciliated cells were observed. After 4 weeks, the broken and dead cells distinctly were increased. However, at 2weeks of

  6. 利奈唑胺与克林霉素对耐甲氧西林金黄色葡萄球菌体外抗菌活性研究%Bactericidal activity of linezolid and clindamycin against methicillin -resistant Staphylococcus aureus in vitro

    Institute of Scientific and Technical Information of China (English)

    周家军; 王睿; 何争民; 孟祥云; 张正升; 季文军; 代文婷; 曹荣娟; 梁蓓蓓

    2015-01-01

    Objective To determinate the antibacterial activity of linezolid and clindamycin agents of clinical methicillin -resistant Staphy-lococcus aureus ( MRSA ) in vitro.Methods The minimum inhibitory concentration ( MIC ) and minimum bactericidal concentration ( MBC ) of antibacterial agents were determined by the micro broth dilution method . Results The linezolid inhibition rate was 100%when the concentration was 2 μg · mL-1 , but clindamycin concentration was 32 μg · mL-1 . The MIC range of linezolid for MRSA was 0.25 ~2.00 μg · mL-1 , MIC50 was 1 μg · mL -1 , MIC90 was 2 μg · mL-1 , MBC50 was 8 μg· mL-1 , MBC90 was 16 μg· mL -1.The MIC range of clindamycin for MRSA was 0.25 ~32.00 μg · mL-1 , MIC50 was 16 μg · mL-1 , MIC90 was 32 μg · mL-1 , MBC50 was 32 μg · mL-1 , MBC90 was >64 μg· mL-1.Conclusion Clindamycin in the treatment of MRSA infection or suspected MRSA infection must depend on drug sensi-tivity test results.Linezolid in the treatment of MRSA infection or suspec-ted MRSA infection has higher reliability .%目的:测定我院临床分离的耐甲氧西林金黄色葡萄球菌( MRSA)对利奈唑胺与克林霉素的体外抗菌活性。方法用微量肉汤稀释法,测定抗菌药物的最低抑菌浓度( MIC )和最低杀菌( MBC )浓度。结果利奈唑胺在浓度为2μg· mL-1时的抑菌率为100%,而克林霉素抑菌率为100%时浓度为32μg· mL-1。利奈唑胺对 MRSA 的 MIC 为0.25~2.00μg · mL-1, MIC50为1μg· mL-1,MIC90为2μg · mL-1, MBC50和 MBC90分别为8μg · mL-1和16μg· mL-1。克林霉素对 MRSA 的 MIC 为0.25~32μg · mL-1, MIC50为16μg· mL-1,MIC90为32μg · mL-1, MBC50和 MBC90分别为32μg · mL-1和>64μg· mL-1。结论克林霉素在治疗MRSA感染或疑似MRSA感染时要以药敏结果为依据,而利奈唑胺用于MRSA感染或疑似MRSA感染的治疗时可靠性更高。

  7. A peptide derived from human bactericidal/permeability-increasing protein (BPI) exerts bactericidal activity against Gram-negative bacterial isolates obtained from clinical cases of bovine mastitis

    Science.gov (United States)

    Gram-negative bacteria are responsible for approximately one-third of the clinical cases of bovine mastitis and can elicit a life-threatening, systemic inflammatory response. Lipopolysaccharide (LPS) is a membrane component of all Gram-negative bacteria and is largely responsible for evoking the de...

  8. Bactericidal activity of black pepper, bay leaf, aniseed and coriander against oral isolates.

    Science.gov (United States)

    Chaudhry, Nazia Masood Ahmed; Tariq, Perween

    2006-07-01

    Present investigation focused on antibacterial potential of aqueous decoction of black pepper (Piper nigrum L.), bay leaf (Laurus nobilis L.), aniseed (Pimpinella anisum L.), and coriander (Coriandum sativum L.) against 176 bacterial isolates belonging to 12 different genera of bacterial population isolated from oral cavity of 200 individuals. The disc diffusion technique was employed. Overall aqueous decoction of black pepper was the most bacterial-toxic exhibited 75% antibacterial activity as compared to aqueous decoction of bay leaf (53.4%) and aqueous decoction of aniseed (18.1%), at the concentration of 10 ml/disc. The aqueous decoction of coriander did not show any antibacterial effect against tested bacterial isolates.

  9. The Lytic SA Phage Demonstrate Bactericidal Activity against Mastitis Causing Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Hamza Ameer

    2016-01-01

    Full Text Available Staphylococcus aureus is the major causative agent of mastitis among dairy animals as it causes intramammary gland infection. Due to antibiotic resistance and contamination of antibiotics in the milk of diseased animals; alternative therapeutic agents are required to cure mastitis. Lytic bacteriophages and their gene products can be potential therapeutic agents against bacteria as they are host specific and less harmful than antibiotics. In this study, Staphylococcus aureus were isolated from milk samples of the infected animals and identified biochemically. SA phage was isolated from sewage water showing lytic activity against Staphylococcus aureus isolates. The highest lytic activity of bacteriophages was observed at 37°C and pH 7, and the most suitable storage condition was at 4°C. SA phage efficiently reduced bacterial growth in the bacterial reduction assay. The characterization and bacterial growth reduction activity of the bacteriophages against Staphylococcus aureus signifies their underlying potential of phage therapy against mastitis.

  10. Bactericidal Effect of a Photoresponsive Carbon Monoxide-Releasing Nonwoven against Staphylococcus aureus Biofilms.

    Science.gov (United States)

    Klinger-Strobel, Mareike; Gläser, Steve; Makarewicz, Oliwia; Wyrwa, Ralf; Weisser, Jürgen; Pletz, Mathias W; Schiller, Alexander

    2016-07-01

    Staphylococcus aureus is a leading pathogen in skin and skin structure infections, including surgical and traumatic infections that are associated with biofilm formation. Because biofilm formation is accompanied by high phenotypic resistance of the embedded bacteria, they are almost impossible to eradicate by conventional antibiotics. Therefore, alternative therapeutic strategies are of high interest. We generated nanostructured hybrid nonwovens via the electrospinning of a photoresponsive carbon monoxide (CO)-releasing molecule [CORM-1, Mn2(CO)10] and the polymer polylactide. This nonwoven showed a CO-induced antimicrobial activity that was sufficient to reduce the biofilm-embedded bacteria by 70% after photostimulation at 405 nm. The released CO increased the concentration of reactive oxygen species (ROS) in the biofilms, suggesting that in addition to inhibiting the electron transport chain, ROS might play a role in the antimicrobial activity of CORMs on S. aureus The nonwoven showed increased cytotoxicity on eukaryotic cells after longer exposure, most probably due to the released lactic acid, that might be acceptable for local and short-time treatments. Therefore, CO-releasing nonwovens might be a promising local antimicrobial therapy against biofilm-associated skin wound infections.

  11. Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition

    OpenAIRE

    Ponja, S. D.; Sehmi, S. K.; Allan, E.; MacRobert, A. J.; Parkin, I. P.; Carmalt, C. J.

    2015-01-01

    Silver thin films were deposited on SiO2-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO2-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activit...

  12. Adsorption and photocatalyst assisted dye removal and bactericidal performance of ZnO/chitosan coating layer.

    Science.gov (United States)

    Kamal, Tahseen; Ul-Islam, Mazhar; Khan, Sher Bahadar; Asiri, Abdullah M

    2015-11-01

    Pure chitosan and its zinc oxide composite coatings were applied on microfibriller cellulose mat (MCM) to prepare chitosan coated microfibriller cellulose (Chi-MCM) and zinc oxide/chitosan coated microfibriller cellulose (ZnO/Chi-MCM), respectively. X-ray diffraction (XRD), and scanning electron microscopy (SEM), were used to characterize the samples in this study. SEM images showed that dense chitosan solutions (3 and 5wt%) made a thick layer over MCM while diluted solution (1wt%) resulted in wrapping of the chitosan over the individual microfibers and avoided the thick layer formation. Removal of an azo dye methyl orange (MO) from aqueous solution using adsorption and combined adsorption with photodegradation activity of the Chi-MCM and ZnO/Chi-MCM were evaluated, respectively. Compared in the absence of UV light, ZnO/Chi-MCM showed faster and higher degree of dye removal by photocatalytic dissociation and adsorption under ultraviolet irradiation. Various parameters including pH of MO solution and its initial concentration were tested for the removal of MO dye. ZnO/Chi-MCM showed maximum adsorption capacity of 42.8mg/g. Antibacterial activities were also evaluated where ZnO/Chi-MCM displayed a remarkable performance inhibiting the Escherichia coli growth.

  13. Impaired bactericidal but not fungicidal activity of polymorphonuclear neutrophils in patients with chronic lymphocytic leukemia.

    Science.gov (United States)

    Kontoyiannis, Dimitrios P; Georgiadou, Sarah P; Wierda, William G; Wright, Susan; Albert, Nathaniel D; Ferrajoli, Alessandra; Keating, Michael; Lewis, Russell E

    2013-08-01

    We examined the qualitative polymorphonuclear neutrophil (PMN)-associated immune impairment in patients with chronic lymphocytic leukemia (CLL) by characterizing phagocytic killing of key non-opsonized bacterial (Staphylococcus aureus and Pseudomonas aeruginosa) and fungal (Candida albicans and Aspergillus fumigatus) pathogens. Neutrophils were collected from 47 non-neutropenic patients with CLL (PMN count > 1000/mm(3)) and age-matched and young healthy controls (five each). A subset of patients (13%) had prior or subsequent infections. We found that the patients with CLL had diminished PMN microbicidal response against bacteria but not against fungi compared with the controls. Compared to patients with effective PMN responses, we did not identify differences of basal PMN pathogen-associated molecular pattern receptor gene expression, soluble pathogen-associated molecular pattern gene expression or inflammatory cytokine signatures in patients with impaired PMN responses when PMNs were analyzed in multiplex real-time polymerase chain reaction assays. However, differences in PMN microbicidal response against A. fumigatus in patients with CLL were associated with the degree of hypogammaglobulinemia.

  14. Bactericidal effect of lactoferrin and lactoferrin chimera against halophilic Vibrio parahaemolyticus

    NARCIS (Netherlands)

    Leon-Sicairos, N.; Canizalez-Roman, A.; de la Garza, M.; Reyes-Lopez, M.; Zazueta-Beltran, J.; Nazmi, K.; Gomez-Gil, B.; Bolscher, J.G.

    2009-01-01

    Infections caused by Vibrio parahaemolyticus, an halophilic member of the genus Vibrio, have increased globally in the last 5 years. Diarrhea caused by V. parahaemolyticus results from eating raw or undercooked seafood. The aim of this work was to investigate whether lactoferrin and some lactoferrin

  15. Acorus calamus rhizome extract mediated biosynthesis of silver nanoparticles and their bactericidal activity against human pathogens

    Directory of Open Access Journals (Sweden)

    Chinnappan Sudhakar

    2015-12-01

    Full Text Available Silver nanoparticle (AgNP synthesis and characterization is an area of vast interest due to their broader application in the fields of science and technology and medicine. Plants are an attractive source for AgNP synthesis because of its ability to produce a wide range of secondary metabolites with strong reducing potentials. Thus, the present study describes the synthesis of AgNPs using aqueous rhizome extract of Acorus calamus (sweet flag. The AgNP formation was evaluated at different temperatures, incubation time and concentrations of AgNO3 using Response surface methodology based Box–Behnken design (BBD. The synthesized AgNPs were characterized by UV–Visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR, X-ray diffraction (XRD, and Scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS. The surface plasmon resonance found at 420 nm confirmed the formation of AgNPs. SEM images reveal that the particles are spherical in nature. The EDS analysis of the AgNPs, using an energy range of 2–4 keV, confirmed the presence of elemental silver without any contamination. The antibacterial activity of synthesized AgNPs was evaluated against the clinical isolates Staphylococcus aureus and Escherichia coli and it was found that bacterial growth was significantly inhibited in a dose dependent manner. The results suggest that the AgNPs from rhizome extract could be used as a potential antibacterial agent for commercial application.

  16. eNAP-2, a novel cysteine-rich bactericidal peptide from equine leukocytes.

    OpenAIRE

    Couto, M A; Harwig, S S; Cullor, J S; Hughes, J. P.; Lehrer, R I

    1992-01-01

    We purified a novel cysteine-rich antibiotic peptide, eNAP-2 (M(r), approximately 6,500), from acid extracts of equine neutrophils by sequential gel filtration and reversed-phase high-performance liquid chromatography and determined its partial N-terminal amino acid sequence. Although its cysteine motif distinguished eNAP-2 from all other currently known endogenous antibiotic peptides, including defensins and granulins, it showed substantial sequence similarity to WDNM1, a putative member of ...

  17. BACTERICIDE IMPACT OF POLYMER-STABILIZED MULTI-FUNCTIONAL NANO-COMPOSITES

    Directory of Open Access Journals (Sweden)

    Graskova I.A.

    2012-08-01

    Full Text Available Synthesis on the basis of natural matrices in order to acquire products with the desired properties is one of the promising trends of modern science. Using polysaccharides as a matrix allowed to generate derivatives with diverse structures and new properties. Growing interest towards anti-microbe effect of selenium-containing nano-composites is induced by the phenomenon of antibiotic-resistance of contemporary pathogenic microorganisms.Clavibacter genus bacteria are the most significant and widely spread among gram-positive bacteria. Bacteria cells are static pleimorphous rods, normally singular, sometimes coupled or joined in short chains, strict anaerobes in need of certain growth factors, non-sporogenous. Clavibacter michiganensis subsp. sepedonicus cause potato ring rot. At the tuber slice the damage is shaped as a ring; growing bacteria are accumulated in the conducting vessels causing their occlusion and therefore gradual withering of leaves and stem. This disease is distributed at all the continents including Australia. Harvest loss through ring rot damage may reach 10-45%.Our work was aimed at the study of complex interaction between microbe cultivar and selenium-based nanocomposites. Bacterial strain Аs1405 was acquired from the All-Russia collection of microorganisms, IMBP RAS. This genus is not included in the classification of pathogenic microorganisms by pathogenic groups of Sanitary-Epidemiological Rules SP 1.3.2322-08. The present study was focused on characteristics of the acquired strain.Fluorescent and electronic-scanning microscope was used to acquire photographs of bacterial cells. Pathogen was identified by PCR-analysis, which confirmed the presence of DNA of desired size. The extracted DNA was sequenced with the sequenced sequence added to Gen Bank under the number HQ394204. Cellulolytic and phytotoxic activity of this strain was determined.Chemistry Institute named A.E. Favorsky provided water-soluble nano-composites containing selenium stabilized by various polymers. Nano-composites anti-microbe activity was studied on the investigated strain of potato ring rot. Nano-composites of elementary selenium (3.4% Se and Se with arabinogalactan acquired from SeO2 (1.23% Se were found to demonstrate anti-microbe effect increasing with the rise of selenium content. The work enumerates various conditions and time periods of cultivation and determination of the influence of the given water-soluble nano-composites on bacterial cells survivability.

  18. In vitro bactericidal activity of aminoglycosides, including the next-generation drug plazomicin, against Brucella spp.

    Science.gov (United States)

    Plazomicin is a next-generation aminoglycoside with a potentially improved safety profile compared to other aminoglycosides. This study assessed plazomicin MICs and MBCs in four Brucella spp. reference strains. Like other aminoglycosides and aminocyclitols, plazomicin MBC values equaled MIC values ...

  19. The Molecular Bacterial Load Assay Replaces Solid Culture for Measuring Early Bactericidal Response to Antituberculosis Treatment

    Science.gov (United States)

    Mtafya, Bariki; Phillips, Patrick P. J.; Hoelscher, Michael; Ntinginya, Elias N.; Kohlenberg, Anke; Rachow, Andrea; Rojas-Ponce, Gabriel; McHugh, Timothy D.; Heinrich, Norbert

    2014-01-01

    We evaluated the use of the molecular bacterial load (MBL) assay, for measuring viable Mycobacterium tuberculosis in sputum, in comparison with solid agar and liquid culture. The MBL assay provides early information on the rate of decline in bacterial load and has technical advantages over culture in either form. PMID:24871215

  20. Plant-mediated synthesis of biosilver nanoparticles using Pandanus amaryllifolius extract and its bactericidal activity

    Energy Technology Data Exchange (ETDEWEB)

    Akhir, Rabiatuladawiyah Md.; Fairuzi, Afiza Ahmad [School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan (Malaysia); Ismail, Nur Hilwani [School of Biology, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan Malaysia (Malaysia)

    2015-08-28

    In this work, we describe a cost effective, easily scaled up and environmental friendly technique for green synthesis of silver nanoparticles (AgNPs) from 5 mM AgNO{sub 3} solution using aqueous extract of Pandanus amaryllifolius (P. amaryllifolius) leaves as reducing agent. Biosynthesized silver nanoparticles was confirmed by sampling the reaction mixture at regular intervals and the absorption maxima was scanned by Ultraviolet-Visible (UV-Vis) spectroscopy at wavelength of 200-500 nm. Images from Field Emission Scanning Electron Microscope (FESEM) have shown that the silver nanoparticles are 17-30 nm in range and assembled in mostly spherical shape. Elemental composition analysis by using Energy Dispersive X-ray (EDX) confirmed the presence of silver. Low concentration of biosynthesized silver nanoparticles have been found to exhibit good antibacterial activity against Staphylococcus aureus bacteria with average mean diameter of zone of inhibition (ZOI) of 16 mm.

  1. EMERGENCE OF MESUA FERREA LINN. LEAF EXTRACT AS A POTENT BACTERICIDE

    OpenAIRE

    Mazumder, Rupa; Dastidar,Sujata G.; Basu, S. P.; Mazumder, Avijit; Kumar, Sanjay

    2003-01-01

    The methanolic extract of leaves of Mesua ferrea Linn. were tested for its antibacterial potentiality against 103 various strains of bacteria including Staphylococcus aureus, Bacillus spps. Klebsiella spps., Streptococus pneumoniae, Sarcina lutea, Lactobacilus arabinosus, Escherichia coli, shigellae, salmonellae, Proteus spps., Pseudomonas spps. and the vibrios. Significant antibacterial effects were produced by the extract against Staphylococcus aureus, Bacillus sppa., lactobacilli, Escheric...

  2. EMERGENCE OF MESUA FERREA LINN. LEAF EXTRACT AS A POTENT BACTERICIDE

    Science.gov (United States)

    Mazumder, Rupa; Dastidar, Sujata G.; Basu, S.P.; Mazumder, Avijit; Kumar, Sanjay

    2003-01-01

    The methanolic extract of leaves of Mesua ferrea Linn. were tested for its antibacterial potentiality against 103 various strains of bacteria including Staphylococcus aureus, Bacillus spps. Klebsiella spps., Streptococus pneumoniae, Sarcina lutea, Lactobacilus arabinosus, Escherichia coli, shigellae, salmonellae, Proteus spps., Pseudomonas spps. and the vibrios. Significant antibacterial effects were produced by the extract against Staphylococcus aureus, Bacillus sppa., lactobacilli, Escherichia coli, shigellae and salmonellae and the results were compared with standard antibiotic ciprofloxacin. Further the extract was proved to be bacterial in its action. PMID:22557104

  3. Emergence of mesua ferrea linn. Leaf extract as a potent bactericide.

    Science.gov (United States)

    Mazumder, Rupa; Dastidar, Sujata G; Basu, S P; Mazumder, Avijit; Kumar, Sanjay

    2003-04-01

    The methanolic extract of leaves of Mesua ferrea Linn. were tested for its antibacterial potentiality against 103 various strains of bacteria including Staphylococcus aureus, Bacillus spps. Klebsiella spps., Streptococus pneumoniae, Sarcina lutea, Lactobacilus arabinosus, Escherichia coli, shigellae, salmonellae, Proteus spps., Pseudomonas spps. and the vibrios. Significant antibacterial effects were produced by the extract against Staphylococcus aureus, Bacillus sppa., lactobacilli, Escherichia coli, shigellae and salmonellae and the results were compared with standard antibiotic ciprofloxacin. Further the extract was proved to be bacterial in its action.

  4. Reactive Oxygen Species Contribute to the Bactericidal Effects of the Fluoroquinolone Moxifloxacin in Streptococcus pneumoniae.

    Science.gov (United States)

    Ferrándiz, M J; Martín-Galiano, A J; Arnanz, C; Zimmerman, T; de la Campa, A G

    2015-11-02

    We studied the transcriptomic response of Streptococcus pneumoniae to the fluoroquinolone moxifloxacin at a concentration that inhibits DNA gyrase. Treatment of the wild-type strain R6, at a concentration of 10× the MIC, triggered a response involving 132 genes after 30 min of treatment. Genes from several metabolic pathways involved in the production of pyruvate were upregulated. These included 3 glycolytic enzymes, which ultimately convert fructose 6-phosphate to pyruvate, and 2 enzymes that funnel phosphate sugars into the glycolytic pathway. In addition, acetyl coenzyme A (acetyl-CoA) carboxylase was downregulated, likely leading to an increase in acetyl-CoA. When coupled with an upregulation in formate acetyltransferase, an increase in acetyl-CoA would raise the production of pyruvate. Since pyruvate is converted by pyruvate oxidase (SpxB) into hydrogen peroxide (H2O2), an increase in pyruvate would augment intracellular H2O2. Here, we confirm a 21-fold increase in the production of H2O2 and a 55-fold increase in the amount of hydroxyl radical in cultures treated during 4 h with moxifloxacin. This increase in hydroxyl radical through the Fenton reaction would damage DNA, lipids, and proteins. These reactive oxygen species contributed to the lethality of the drug, a conclusion supported by the observed protective effects of an SpxB deletion. These results support the model whereby fluoroquinolones cause redox alterations. The transcriptional response of S. pneumoniae to moxifloxacin is compared with the response to levofloxacin, an inhibitor of topoisomerase IV. Levofloxacin triggers the transcriptional activation of iron transport genes and also enhances the Fenton reaction.

  5. Bactericidal properties of group IIA and group V phospholipases A2

    NARCIS (Netherlands)

    Grönroos, J.O.; Laine, V.J.O.; Janssen, M.J.W.; Egmond, M.R.; Nevalainen, T.J.

    2010-01-01

    Group V phospholipase A2 (PLA2) is a recently characterized 14-kDa secretory PLA2 of mammalian heart and macrophage-derived cells. Group IIA PLA2, which is structurally close to group V PLA2, has been shown to kill Gram-positive bacteria in vitro and to prevent symptoms of Gram-positive infection in

  6. Bactericidal action mechanism of negatively charged food grade clove oil nanoemulsions.

    Science.gov (United States)

    Majeed, Hamid; Liu, Fei; Hategekimana, Joseph; Sharif, Hafiz Rizwan; Qi, Jing; Ali, Barkat; Bian, Yuan-Yuan; Ma, Jianguo; Yokoyama, Wallace; Zhong, Fang

    2016-04-15

    Clove oil (CO) anionic nanoemulsions were prepared with varying ratios of CO to canola oil (CA), emulsified and stabilized with purity gum ultra (PGU), a newly developed succinylated waxy maize starch. Interfacial tension measurements showed that CO acted as a co-surfactant and there was a gradual decrease in interfacial tension which favored the formation of small droplet sizes on homogenization until a critical limit (5:5% v/v CO:CA) was reached. Antimicrobial activity of the negatively charged CO nanoemulsion was determined against Gram positive GPB (Listeria monocytogenes and Staphylococcus aureus) and Gram negative GNB (Escherichia coli) bacterial strains using minimum inhibitory concentration (MIC) and a time kill dynamic method. Negatively charged PGU emulsified CO nanoemulsion showed prolonged antibacterial activities against Gram positive bacterial strains. We concluded that negatively charged CO nanoemulsion droplets self-assemble with GPB cell membrane, and facilitated interaction with cellular components of bacteria. Moreover, no electrostatic interaction existed between negatively charged droplets and the GPB membrane.

  7. Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current

    Directory of Open Access Journals (Sweden)

    Żaneta Król

    2017-03-01

    Full Text Available The aim of the study was to investigate the effect of using direct electric current (DC of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP, electrical conductivity (EC, and available chlorine concentration (ACC were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH and ferric reducing antioxidant power (FRAP. The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples.

  8. An alternative bactericidal mechanism of action for lantibiotic peptides that target lipid II

    NARCIS (Netherlands)

    Hasper, Hester E.; Kramer, Naomi E.; Smith, James L.; Hillman, J. D.; Zachariah, Cherian; Kuipers, Oscar P.; de Kruijff, Ben; Breukink, Eefjan

    2006-01-01

    Lantibiotics are polycyclic peptides containing unusual amino acids, which have binding specificity for bacterial cells, targeting the bacterial cell wall component lipid II to form pores and thereby lyse the cells. Yet several members of these lipid II - targeted lantibiotics are too short to be ab

  9. Bactericidal and ammonia removal activity of silver ion-exchanged zeolite.

    Science.gov (United States)

    Krishnani, K K; Zhang, Yu; Xiong, Laj; Yan, Yushan; Boopathy, Raj; Mulchandani, Ashok

    2012-08-01

    The antimicrobial activity of silver-zeolite against Escherichia coli, Vibrio harveyi, Vibrio cholerae and Vibrio parahaemolyticus was examined in liquid medium and agar well diffusion assays. The minimum inhibitory concentration for silver ion-exchanged zeolite against E. coli and V. harveyi was 40 μg/ml, and 50-60 μg/ml for V. cholerae and V. parahaemolyticus. The diameter of the inhibition zones for E. coli, V. harveyi, V. cholerae and V. parahaemolyticus, respectively, increased from 0.5 to 2.3 cm, 0.6 to 2.4 cm, 0.3 to 1.65 cm and 0.3 to 1.7 cm with increasing concentrations of silver ion-exchanged zeolite from 10 to 400 μg. Silver-zeolite removed 20-37% ammonia from aqueous solutions. This study suggests that silver ion-exchanged zeolite could impact disease and environmental management in shrimp aquaculture.

  10. Bactericidal activity of green tea extracts: the importance of catechin containing nano particles

    OpenAIRE

    Judy Gopal; Manikandan Muthu; Diby Paul; Doo-Hwan Kim; Sechul Chun

    2016-01-01

    When we drink green tea infusion, we believe we are drinking the extract of the green tea leaves. While practically each tea bag infused in 300 mL water contains about 50 mg of suspended green tea leaf particles. What is the role of these particles in the green tea effect is the objective of this study. These particles (three different size ranges) were isolated via varying speed centrifugation and their respective inputs evaluated. Live oral bacterial samples from human volunteers have been ...

  11. Bactericidal paper impregnated with silver nanoparticles for point-of-use water treatment.

    Science.gov (United States)

    Dankovich, Theresa A; Gray, Derek G

    2011-03-01

    There is an urgent need for cheap point-of-use methods to purify drinking water. We describe a method to deactivate pathogenic bacteria by percolation through a paper sheet containing silver nanoparticles. The silver nanoparticles are deposited by the in situ reduction of silver nitrate on the cellulose fibers of an absorbent blotting paper sheet. The aim is to achieve inactivation of bacteria during percolation through the sheet, rather than removal of bacteria from the effluent by filtration. The silver-nanoparticle containing (AgNP) papers were tested for performance in the laboratory with respect to bacteria inactivation and silver leaching as suspensions of bacteria percolated through the paper. The AgNP sheets exhibited antibacterial properties toward suspensions of Escherichia coli and Enterococcus faecalis, with log reduction values in the effluent of over log 6 and log 3, respectively. The silver loss from the AgNP sheets was minimal, with values under 0.1 ppm (the current US EPA and WHO limit for silver in drinking water). These results show promise that percolation of bacterially contaminated water through paper embedded with silver nanoparticles could be an effective emergency water treatment.

  12. Graphene Oxide Quantum Dots Covalently Functionalized PVDF Membrane with Significantly-Enhanced Bactericidal and Antibiofouling Performances

    Science.gov (United States)

    Zeng, Zhiping; Yu, Dingshan; He, Ziming; Liu, Jing; Xiao, Fang-Xing; Zhang, Yan; Wang, Rong; Bhattacharyya, Dibakar; Tan, Timothy Thatt Yang

    2016-02-01

    Covalent bonding of graphene oxide quantum dots (GOQDs) onto amino modified polyvinylidene fluoride (PVDF) membrane has generated a new type of nano-carbon functionalized membrane with significantly enhanced antibacterial and antibiofouling properties. A continuous filtration test using E. coli containing feedwater shows that the relative flux drop over GOQDs modified PVDF is 23%, which is significantly lower than those over pristine PVDF (86%) and GO-sheet modified PVDF (62%) after 10 h of filtration. The presence of GOQD coating layer effectively inactivates E. coli and S. aureus cells, and prevents the biofilm formation on the membrane surface, producing excellent antimicrobial activity and potentially antibiofouling capability, more superior than those of previously reported two-dimensional GO sheets and one-dimensional CNTs modified membranes. The distinctive antimicrobial and antibiofouling performances could be attributed to the unique structure and uniform dispersion of GOQDs, enabling the exposure of a larger fraction of active edges and facilitating the formation of oxidation stress. Furthermore, GOQDs modified membrane possesses satisfying long-term stability and durability due to the strong covalent interaction between PVDF and GOQDs. This study opens up a new synthetic avenue in the fabrication of efficient surface-functionalized polymer membranes for potential waste water treatment and biomolecules separation.

  13. Capture stress and the bactericidal competence of blood and plasma in five species of tropical birds.

    Science.gov (United States)

    Matson, Kevin D; Tieleman, B Irene; Klasing, Kirk C

    2006-01-01

    In wild birds, relatively little is known about intra- or interspecific variation in immunological capabilities, and even less is known about the effects of stress on immune function. Immunological assays adaptable to field settings and suitable for a wide variety of taxa will prove most useful for addressing these issues. We describe a novel application of an in vitro technique that measures the intrinsic bacteria-killing abilities of blood. We assessed the capacities of whole blood and plasma from free-living individuals of five tropical bird species to kill a nonpathogenic strain of E. coli before and after the birds experienced an acute stress. Killing invasive bacteria is a fundamental immune function, and the bacteria-killing assay measures constitutive, innate immunity integrated across circulating cell and protein components. Killing ability varied significantly across species, with common ground doves exhibiting the lowest levels and blue-crowned motmots exhibiting the highest levels. Across species, plasma killed bacteria as effectively as whole blood, and higher concentrations of plasma killed significantly better. One hour of acute stress reduced killing ability by up to 40%. This assay is expected to be useful in evolutionary and ecological studies dealing with physiological and immunological differences in birds.

  14. Laser assisted periodontal treatment: from bactericidal effect to local modification of the host response

    Science.gov (United States)

    Ciurescu, Codruţa.; Teslaru, Silvia; Zetu, Liviu; Ciurescu, Daniel

    2016-03-01

    The aim of the present short-term study is to investigate efficiency of laser therapy as adjunct to conventional periodontal therapy in patients with chronic periodontitis. Methods. The study protocol included 44 patients (20 males, 24 females; age 45-60) with moderate and advanced chronic periodontitis, recruited in Private Clinic Krondent (Brasov, Romania). The patients were randomly assigned in two groups, one group (test-sites group, 22 patients) treated by ultrasonic scaling and root planning followed by laser therapy (940 nm diode laser and 2780 nm Er:Cr:YAG laser) and second group (control-sites group, 22 patients) treated only by ultrasonic scaling and root planning. All patients were submitted to initial evaluation, recording of bleeding on probing (BOP) and probing of pockets depth (PPD), oral hygiene instruction and motivation. Indices BOP and PPD for the assessed periodontal sites were also recorded at 8 weeks, 16 weeks and 24 weeks after treatment. Results. Periodontal inflammatory parameters PPD (PPD>=4mm) were significantly lower in test-sites group as compared with control-sites group at 2 months (82% vs. 90%), 4 months (42% vs. 62%), and 6 months (11% vs. 30%).Periodontal parameters BOP were lower among patients in control-sites group and test-sites group at 2 months (38% vs. 32%), and significantly lower in test-sites group at 4 months (42% vs.26%), and 6 months (44% vs. 24%). Conclusions. The additional use of laser therapy increases significantly the efficiency of periodontal treatment comparing with conventional periodontal therapy.

  15. BAGEL3: Automated identification of genes encoding bacteriocins and (non-)bactericidal posttranslationally modified peptides.

    Science.gov (United States)

    van Heel, Auke J; de Jong, Anne; Montalbán-López, Manuel; Kok, Jan; Kuipers, Oscar P

    2013-07-01

    Identifying genes encoding bacteriocins and ribosomally synthesized and posttranslationally modified peptides (RiPPs) can be a challenging task. Especially those peptides that do not have strong homology to previously identified peptides can easily be overlooked. Extensive use of BAGEL2 and user feedback has led us to develop BAGEL3. BAGEL3 features genome mining of prokaryotes, which is largely independent of open reading frame (ORF) predictions and has been extended to cover more (novel) classes of posttranslationally modified peptides. BAGEL3 uses an identification approach that combines direct mining for the gene and indirect mining via context genes. Especially for heavily modified peptides like lanthipeptides, sactipeptides, glycocins and others, this genetic context harbors valuable information that is used for mining purposes. The bacteriocin and context protein databases have been updated and it is now easy for users to submit novel bacteriocins or RiPPs. The output has been simplified to allow user-friendly analysis of the results, in particular for large (meta-genomic) datasets. The genetic context of identified candidate genes is fully annotated. As input, BAGEL3 uses FASTA DNA sequences or folders containing multiple FASTA formatted files. BAGEL3 is freely accessible at http://bagel.molgenrug.nl.

  16. Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment

    DEFF Research Database (Denmark)

    Kolpen, Mette; Mousavi, Nabi; Sams, Thomas

    2016-01-01

    of O2-depleted biofilms may thus improve susceptibility to ciprofloxacin possibly by restoring aerobic respiration. We tested such a strategy using reoxygenation of O2-depleted P. aeruginosa strain PAO1 agarose-embedded biofilms by hyperbaric oxygen treatment (HBOT) (100% O2, 2.8bar), enhancing...

  17. Antibiotic-eluting hydrophilized PMMA bone cement with prolonged bactericidal effect for the treatment of osteomyelitis.

    Science.gov (United States)

    Oh, Eun Jo; Oh, Se Heang; Lee, In Soo; Kwon, Oh Soo; Lee, Jin Ho

    2016-05-01

    Osteomyelitis is still considered to be one of the major challenges for orthopedic surgeons despite advanced antiseptic surgical procedures and pharmaceutical therapeutics. In this study, hydrophilized poly(methyl methacrylate) (PMMA) bone cements containing Pluronic F68 (EG79PG28EG79) as a hydrophilic additive and vancomycin (F68-VAcements) were prepared to allow the sustained release of the antibiotic for adequate periods of time without any significant loss of mechanical properties. The compressive strengths of the bone cements with Pluronic F68 compositions less than 7 wt% were not significantly different compared with the control vancomycin-loaded bone cement (VAcement). TheF68 (7 wt%)-VAcement showed sustained release of the antibiotic for up to 11 weeks and almost 100% release from the bone cement. It also prohibited the growth ofS. aureus(zone of inhibition) over six weeks (the required period to treat osteomyelitis), and it did not show any notable cytotoxicity. From an animal study using a femoral osteomyelitis rat model, it was observed that theF68 (7 wt%)-VAcement was effective for the treatment of osteomyelitis, probably as a result of the prolonged release of antibiotic from the PMMA bone cement. On the basis of these findings, it can be suggested that the use of Pluronic F68 as a hydrophilic additive for antibiotic-eluting PMMA bone cement can be a promising strategy for the treatment of osteomyelitis.

  18. Impact of feed spacer and membrane modification by hydrophilic, bactericidal and biocidal coating on biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The influence of polydopamine- and polydopamine-. graft-poly(ethylene glycol)-coated feed spacers and membranes, copper-coated feed spacers, and commercially-available biostatic feed spacers on biofouling has been studied in membrane fouling simulators. Feed spacers and membranes applied in practical membrane filtration systems were used; biofouling development was monitored by feed channel pressure drop increase and biomass accumulation. Polydopamine and polydopamine-. g-PEG are hydrophilic surface modification agents expected to resist protein and bacterial adhesion, while copper feed spacer coatings and biocides infused in feed spacers are expected to restrict biological growth. Our studies showed that polydopamine and polydopamine-. g-PEG coatings on feed spacers and membranes, copper coatings on feed spacers, and a commercial biostatic feed spacer did not have a significant impact on feed channel pressure drop increase and biofilm accumulation as measured by ATP and TOC content. The studied spacer and membrane modifications were not effective for biofouling control; it is doubtful that feed spacer and membrane modification, in general, may be effective for biofouling control regardless of the type of applied coating. © 2012 Elsevier B.V.

  19. The bactericidal activity of β-lactam antibiotics is increased by metabolizable sugar species

    DEFF Research Database (Denmark)

    Thorsing, Mette; Bentin, Thomas; Givskov, Michael;

    2015-01-01

    Here, the influence of metabolizable sugars on the susceptibility of Escherichia coli to β-lactam antibiotics was investigated. Notably, monitoring growth and survival of mono- and combination-treated planktonic cultures showed a 1000- to 10 000-fold higher antibacterial efficacy of carbenicillin...... and cefuroxime in the presence of certain sugars, whereas other metabolites had no effect on β-lactam sensitivity. This effect was unrelated to changes in growth rate. Light microscopy and flow cytometry profiling revealed that bacterial filaments, formed due to β-lactam-mediated inhibition of cell division......, rapidly appeared upon β-lactam mono-treatment and remained stable for up to 18 h. The presence of metabolizable sugars in the medium did not change the rate of filamentation, but led to lysis of the filaments within a few hours. No lysis occurred in E. coli mutants unable to metabolize the sugars, thus...

  20. Bactericidal Efficacy of Allium sativum (garlic Against Multidrug Resistant Vibrio cholerae O1 Epidemic Strains

    Directory of Open Access Journals (Sweden)

    Pramod Kumar

    2016-09-01

    Full Text Available In recent years, emerging trend of antibiotic resistance in Vibrio cholerae associated with cholera epidemics is a matter of serious concern for the management of the disease. Indiscriminate use of antibiotics generally results in selection of antibiotic resistant strains. Introduction of newer antibiotics is a challenging task for the researchers as bacteria soon attain resistance. Therefore, identifying natural compounds of medicinal importance for control of cholera would be the best alternative. Garlic (Allium sativum was recognised for many centuries in early Chinese, Egyptian and Indian civilisations as an herbal or traditional medicine. In present study, garlic was selected for screening of antimicrobial efficacy against V. cholerae. A total of 55 V. cholerae strains isolated from various outbreaks/epidemics were subjected to antimicrobial testing as per CLSI, USA 2010 guidelines. Antimicrobial screening of garlic extract was performed against all the multidrug resistant strains of V. cholerae. The garlic extracts showed antibacterial activity against all the V. cholerae strains tested, irrespective of their origin, multidrug resistance and virulence. Antibacterial efficacy of garlic on V. cholerae was also evident from in vivo study on sealed adult mice model. Thus, the Garlic extract harnesses the potential to control infection of multidrug resistant V. cholerae, especially in outbreak like situations in remote and under developed areas where drug supply itself is a challenge

  1. Bactericide serum assay to assess the immune response induced by meningococcal and cholera vaccines

    Directory of Open Access Journals (Sweden)

    Bárbara Cedré

    2012-12-01

    Full Text Available La susceptibilidad al sistema bactericida del suero es una característica de las bacterias gramnegativas. Existen muchos ejemplos en las enterobacterias, de hecho cualquier procariote que presente una membrana lipídica pudiera ser potencialmente susceptible a la lisis mediada por anticuerpos dependiente del complemento, aunque existen cepas que muestran resistencia al sistema bacteriolítico. Estas son frecuentemente aisladas como agente causal de infecciones que involucran daño tisular, lo que indica que la resistencia a la actividad lítica del suero es determinante de la virulencia en algunas infecciones debido a bacterias gramnegativas. Para algunas enfermedades causadas por estas bacterias la vacunación constituye la medida de prevención más efectiva, como es el caso del cólera y la enfermedad meningocócica. La inducción de anticuerpos con capacidad lítica, producto de la vacunación, se considera en muchos casos el mejor correlato con la protección y se estima que individuos que desarrollan anticuerpos bactericidas, ya sea por una infección clínica o por la vacunación, están protegidos contra la infección o la enfermedad. De ahí que el ensayo bactericida del suero sea la prueba de oro para evaluar la eficacia de muchas vacunas. Ensayos clínicos llevados a cabo con vacunas contra los serogrupos A, B, C, Y y W 135 de N. meningitidis y con vacunas de cólera, ya sean vivas atenuadas o inactivadas, han demostrado la inducción de anticuerpos con actividad lítica que luego han correlacionado con la protección en ensayos de eficacia o frente a un reto experimental. Por lo que resulta imprescindible la estandarización y validación de estos ensayos para su empleo como criterio de inmunogenicidad en el desarrollo de estas vacunas.

  2. Silver nanoparticles strongly enhance and restore bactericidal activity of inactive antibiotics against multiresistant Enterobacteriaceae.

    Science.gov (United States)

    Panáček, Aleš; Smékalová, Monika; Večeřová, Renata; Bogdanová, Kateřina; Röderová, Magdaléna; Kolář, Milan; Kilianová, Martina; Hradilová, Šárka; Froning, Jens P; Havrdová, Markéta; Prucek, Robert; Zbořil, Radek; Kvítek, Libor

    2016-06-01

    Bacterial resistance to conventional antibiotics is currently one of the most important healthcare issues, and has serious negative impacts on medical practice. This study presents a potential solution to this problem, using the strong synergistic effects of antibiotics combined with silver nanoparticles (NPs). Silver NPs inhibit bacterial growth via a multilevel mode of antibacterial action at concentrations ranging from a few ppm to tens of ppm. Silver NPs strongly enhanced antibacterial activity against multiresistant, β-lactamase and carbapenemase-producing Enterobacteriaceae when combined with the following antibiotics: cefotaxime, ceftazidime, meropenem, ciprofloxacin and gentamicin. All the antibiotics, when combined with silver NPs, showed enhanced antibacterial activity at concentrations far below the minimum inhibitory concentrations (tenths to hundredths of one ppm) of individual antibiotics and silver NPs. The enhanced activity of antibiotics combined with silver NPs, especially meropenem, was weaker against non-resistant bacteria than against resistant bacteria. The double disk synergy test showed that bacteria produced no β-lactamase when treated with antibiotics combined with silver NPs. Low silver concentrations were required for effective enhancement of antibacterial activity against multiresistant bacteria. These low silver concentrations showed no cytotoxic effect towards mammalian cells, an important feature for potential medical applications.

  3. Bactericidal Activity of TiO2 on Cells of Pseudomonas aeruginosa ATCC 27853

    Directory of Open Access Journals (Sweden)

    J. L. Aguilar Salinas

    2013-01-01

    Full Text Available The photocatalytic activity of semiconductors is increasingly being used to disinfect water, air, soils, and surfaces. Titanium dioxide (TiO2 is widely used as a photocatalyst in thin films, powder, and in mixtures with other semiconductors or metals. This work presents the antibacterial effects of TiO2 and light exposure (at 365 nm on Pseudomonas aeruginosa ATCC 27853. TiO2 powder was prepared from a mixture of titanium isopropoxide, ethanol, and nitric acid using a green and short time sol-gel technique. The obtained gel annealed at 450°C was characterized by X-ray diffraction, Raman spectroscopy, ultraviolet-visible spectroscopy, diffuse reflectance, scanning electron microscopy, and transmission electron microscopy. The nanocomposite effectively catalyzed the inactivation of Pseudomonas aeruginosa. Following 90 minutes exposure to TiO2 and UV light, logarithm of cell density was reduced from 6 to 3. These results were confirmed by a factorial design incorporating two experimental replicates and two independent factors.

  4. Antimicrobial Peptides Containing Unnatural Amino Acid Exhibit Potent Bactericidal Activity against ESKAPE Pathogens

    Science.gov (United States)

    2013-01-01

    bacterial strains as previously reported by Hicks and co-workers45 Bacteria Compound 23 64 61 Yersinia pestis C092 500 62.5 32.2 Brucella melitensis...16M 500 125 125 Brucella abortus 2308 500 62.5 125 Francisella tularensis 250 0.04 125 Burkholderia mallei 500 0.04 500 Burkholderia pseudomallei 500

  5. Combined bactericidal activity of silver nanoparticles and hexadecylpyridinium salicylate ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Leonardo T. [Universidade Federal de São Paulo, Laboratório de Materiais Híbridos, Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas (Brazil); Liberatore, Ana Maria A.; Koh, Ivan H. J. [Universidade Federal de São Paulo, Laboratório de Transplante Experimental de Órgãos, Departamento de Cirurgia, Escola Paulista de Medicina (Brazil); Bizeto, Marcos A.; Camilo, Fernanda F., E-mail: ffcamilo@unifesp.br [Universidade Federal de São Paulo, Laboratório de Materiais Híbridos, Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas (Brazil)

    2015-03-15

    Recently, ionic liquids have been used as dispersing agents for silver nanoparticle (AgNP) preparation. In this paper, we have shown a simple method to prepare AgNP in aqueous media using an ionic liquid called hexadecylpyridinium salicylate (HDPSal) as dispersing agent. The dispersions were produced by the chemical reduction of silver ions in aqueous media with different concentrations of HDPSal and tetrabutylammonium borohydride as reducing agent. The UV–Visible electronic spectra showed the characteristic plasmonic resonance band around 420 nm, confirming the formation of AgNPs. The TEM images confirmed the formation of spherical particles with diameters lower than 10 nm. The charge of these particles was determined by Zeta potential and they were around +50 mV, indicating that the HDP cations are surrounding the AgNPs, avoiding their agglomeration. Most of the dispersions remained stable for at least 1 month. Microbiological assays showed that the combination of AgNP with HDPSal results in wider range of antimicrobial effect.

  6. Reclamation Of Plant Wastes (Straw And Obtaining (Nano Chips With Bactericidal Properties Based On Them

    Directory of Open Access Journals (Sweden)

    Leonidovna Voropaeva Nadezda

    2015-09-01

    Full Text Available Rape, camelina, wheat and Jerusalem artichoke vegetable wastes (straw as annually renewable raw materials were processed into activated carbons, which were modified with silver nanoparticles for carbonaceous sorbents to acquire specific properties, since carbonaceous sorbents are usually widely used in the food industry, agriculture, medicine and other fields of human activity. The technology to obtain active carbons from agricultural crop residues has been developed, active carbon physico-chemical and adsorption properties, textural characteristics have been studied, new functional carbon (nano materials with antibacterial activity containing (nano particles of silver have been obtained, their influence within (nano chip composition on rape crop growth, development and yield has been studied. In the conducted field tests, the highest activity was noted when using the (nano chip whose structure included RAC - camelina and silver nanoparticles. Besides, when nano chips are used for seed treatment, the yield increase makes up 11.6 % for nanoparticles containing Ag, for plant active carbons (PAC (rape with Ag this index makes up 28.1 %, for RAC (Camelina with Ag it makes up 55.8 % (compared to the control variant, which can be explained by the differences in the sorption characteristics of the studied radio activated carbons. Our results and the previous studies of other authors can prove the fact that silver nanoparticles (including those being a part of (nano chips “get” into the biochemical processes and have a pronounced phytostimulating effect on plants, which was especially obvious when suppressing the activity of plant pathogenic microflora by silver nanoparticles.

  7. High Quality Bioreplication of Intricate Nanostructures from a Fragile Gecko Skin Surface with Bactericidal Properties

    Science.gov (United States)

    Green, David William; Lee, Kenneth Ka-Ho; Watson, Jolanta Anna; Kim, Hyun-Yi; Yoon, Kyung-Sik; Kim, Eun-Jung; Lee, Jong-Min; Watson, Gregory Shaun; Jung, Han-Sung

    2017-01-01

    The external epithelial surfaces of plants and animals are frequently carpeted with small micro- and nanostructures, which broadens their adaptive capabilities in challenging physical habitats. Hairs and other shaped protuberances manage with excessive water, light contaminants, predators or parasites in innovative ways. We are interested in transferring these intricate architectures onto biomedical devices and daily-life surfaces. Such a project requires a very rapid and accurate small-scale fabrication process not involving lithography. In this study, we describe a simple benchtop biotemplating method using shed gecko lizard skin that generates duplicates that closely replicate the small nanotipped hairs (spinules) that cover the original skin. Synthetic replication of the spinule arrays in popular biomaterials closely matched the natural spinules in length. More significantly, the shape, curvature and nanotips of the synthetic arrays are virtually identical to the natural ones. Despite some small differences, the synthetic gecko skin surface resisted wetting and bacterial contamination at the same level as natural shed skin templates. Such synthetic gecko skin surfaces are excellent platforms to test for bacterial control in clinical settings. We envision testing the biocidal properties of the well-matched templates for fungal spores and viral resistance in biomedicine as well as co/multi-cultures.

  8. Capture stress and the bactericidal competence of blood and plasma in five species of tropical birds

    NARCIS (Netherlands)

    Matson, KD; Tieleman, BI; Klasing, KC; Klasing, Kirk C.

    2006-01-01

    In wild birds, relatively little is known about intra- or interspecific variation in immunological capabilities, and even less is known about the effects of stress on immune function. Immunological assays adaptable to field settings and suitable for a wide variety of taxa will prove most useful for

  9. Capture Stress and the Bactericidal Competence of Blood and Plasma in Five Species of Tropical Birds

    NARCIS (Netherlands)

    Matson, K.D.; Tieleman, B.I.; Klasing, K.C.

    2006-01-01

    In wild birds, relatively little is known about intra- or interspecific variation in immunological capabilities, and even less is known about the effects of stress on immune function. Immunological assays adaptable to field settings and suitable for a wide variety of taxa will prove most useful for

  10. Investigations on bactericidal properties of molybdenum-tungsten oxides combinatorial thin film material libraries.

    Science.gov (United States)

    Mardare, Cezarina Cela; Hassel, Achim Walter

    2014-11-10

    A combinatorial thin film material library from the molybdenum-tungsten refractory metals oxides system was prepared by thermal coevaporation, and its structural and morphological properties were investigated after a multiple step heat treatment. A mixture of crystalline and amorphous oxides and suboxides was obtained, as well as surface structuring caused by the enrichment of molybdenum oxides in large grains. It was found that the oxide phases and the surface morphology change as a function of the compositional gradient. Tests of the library antimicrobial activity against E. coli were performed and the antimicrobial activity was proven in some defined compositional ranges. A mechanism for explaining the observed activity is proposed, involving a collective contribution from (i) increased local acidity due to the enrichment in large grains of molybdenum oxides with different stoichiometry and (ii) the release of free radicals from the W18O49 phase under visible light.

  11. BACTERICIDAL EFFECTS OF VARIOUS IRRIGATION SOLUTIONS AGAINST STAPHYLOCOCCUS AUREUS IN HUMAN ROOT CANAL

    Directory of Open Access Journals (Sweden)

    Recai Zan

    2015-01-01

    Full Text Available Purpose: The aim of the present study was to evaluate and to compare the antibacterial effects of various irrigation solutions against Staphylococcus aureus (S. aureus in human root canals. Materials and Methods: 120 single-root mandibular premolar teeth were selected. The teeth were prepared and sterilized. S. aureus was incubated in the root canals and kept at 37°C for 24h. The infected root canals were divided into one positive (saline and one negative (sodium hypochlorite control, and four experimental groups [Ethylene-diaminetetra-aceticacid, Chlorhexidine Gluconate, Super-oxidized water(SPO, Aqueous ozone] (n=20. Flow rate of irrigation was applied with 5 mL/min flow rate for 3 min to ensure standardization among all study groups. Following the irrigation, paper points were placed in the root canals and then transferred in sterile eppendorf. Remaining bacteria were counted on blood agar plates and the data were analyzed using one-way ANOVA and Tukey’s test. Results: Although there were statistically significant differences among SPO and other experimental groups (p0.05. Conclusion: Super-oxidized water may be recommended as an alternative irrigation solution instead of NaOCl against S. aureus in root canals.

  12. A heterodimer comprised of two bovine lactoferrin antimicrobial peptides exhibits powerful bactericidal activity against Burkholderia pseudomallei

    NARCIS (Netherlands)

    Puknun, A.; Bolscher, J.G.M.; Nazmi, K.; Veerman, E.C.I.; Tungpradabkul, S.; Wongratanacheewin, S.; Kanthawong, S.; Taweechaisupapong, S.

    2013-01-01

    Melioidosis is a severe infectious disease that is endemic in Southeast Asia and Northern Australia. Burkholderia pseudomallei, the causative agent of this disease, has developed resistance to an increasing list of antibiotics, demanding a search for novel agents. Lactoferricin and lactoferrampin ar

  13. Development of polymeric nanocomposites with enhanced distribution of catalytically active or bactericide nanoparticles

    OpenAIRE

    Alonso González, Amanda

    2012-01-01

    Esta tesis es un trabajo interdisciplinario dirigido a la obtención de nuevos nanocompuestos funcionales sintetizados a partir de materiales poliméricos intercambiadores de iones modificados por nanopartículas (NPs) de diferente composición. El desarrollo de nanomateriales es de gran interés en la actualidad dada sus especiales propiedades que difieren de las de la materia a escala macroscópica y que pueden resultar en ventajas tecnológicas. Sin embargo, existe cierta preocupación relativa a ...

  14. Survival of Bactericidal Antibiotic Treatment by a Persister Subpopulation of Listeria monocytogenes

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Ng, Yin; Gram, Lone

    2013-01-01

    Listeria monocytogenes can cause the serious infection listeriosis, which despite antibiotic treatment has a high mortality. Understanding the response of L. monocytogenes to antibiotic exposure is therefore important to ensure treatment success. Some bacteria survive antibiotic treatment...

  15. Bactericidal efficacy of a 1.5min surgical hand-rubbing protocol under in-use conditions.

    Science.gov (United States)

    Kac, G; Masmejean, E; Gueneret, M; Rodi, A; Peyrard, S; Podglajen, I

    2009-06-01

    In healthy volunteers, surgical hand rubbing with Sterillium for 1.5min has been shown to be as effective as a 3min procedure. The aim of this study was to assess whether this result was reproducible under in-use conditions. During nine weeks in the ambulatory surgery theatre of a 750-bed tertiary care university hospital, the two surgical hand-rubbing procedures were compared with each other, and with a hand-scrubbing procedure using a povidone-iodine (4%) scrub prior to and after 25 different surgical operations for each. Imprints of the surgeon's dominant hand were taken on culture plates before and within 1min following the end of the hand-rubbing/scrubbing procedures (immediate effect) and at the end of surgery (sustained effect). Plates were incubated aerobically at 37 degrees C for 48h. Colonies were counted at 24h and 48h. Results were expressed as the number of colony-forming units per hand. No significant difference in baseline hand bacterial load was found before the hand-rubbing/scrubbing procedures among the three groups (P=0.19). With respect to immediate and sustained antimicrobial effects, a significantly greater reduction in microbial loads on the hands was achieved with the 3min hand-rubbing protocol as opposed to hand-scrubbing protocol (P=0.04 and P=0.02, respectively), but there was no difference between the reductions obtained with 1.5 and 3min rubbing protocols (P=0.41 and P=0.36, respectively). Surgical hand rubbing with Sterillium using a 1.5min protocol should be considered as an attractive alternative method for surgical hand disinfection.

  16. Bactericidal effects of silver plus titanium dioxide-coated endotracheal tubes on Pseudomonas aeruginosa and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Keiko M Tarquinio

    2010-03-01

    Full Text Available Keiko M Tarquinio1, Nikhil K Kothurkar2, Dharendra Y Goswami3, Ronald C Sanders Jr4, Arno L Zaritsky5, Ann Marie LeVine61Division of Pediatric Critical Care Medicine, Department of Pediatrics, Rhode Island Hospital, The Warren Alpert Medical School, Brown University, Providence, RI USA; 2Department of Chemical Engineering and Materials Science, Amrita School of Engineering, Ettimadai, Coimbatore, India; 3Clean Energy Research Center, University of South Florida, Tampa, FL, USA; 4Section of Pediatric Critical Care, Department of Pediatrics, College of Medicine, University of Arkansas for Medical Sciences, Arkansas Children’s Hospital, Little Rock, AR, USA; 5Executive Medical Director, Children’s Hospital of The King’s Daughters, Norfolk, VA, USA; 6Pediatric Critical Care Medicine, University of Michigan Medical School, C.S. Mott Children’s Hospital, Ann Arbor, MI, USAPurpose: Ventilator-associated pneumonia (VAP is a nosocomial infection resulting in significant morbidity and mortality. Pseudomonas aeruginosa (P. aeruginosa and Staphylococcus aureus (S. aureus are pathogens associated with VAP. Silver (Ag coating of endotracheal tubes (ETTs reduces bacterial colonization, however titanium dioxide (TiO2 coating has not been studied.Methods: Five types of ETT coatings were applied over silica layer: Ag, solgel TiO2, solgel TiO2 with Ag, Degussa P25 TiO2 (Degussa TiO2, and Degussa TiO2 with Ag. After ETTs were incubated with P. aeruginosa or S. aureus; colonization was determined quantitatively.Results: Pseudomonas aeruginosa and S. aureus grew for 5 days on standard ETTs. Compared to standard ETTs, P. aeruginosa growth was significantly inhibited by solgel TiO2 with Ag at 24 hours, and by Degussa TiO2 with Ag at 24 and 48 hours after inoculation. No significant difference in S. aureus growth was observed between the control and any of the five coatings for 5 days.Conclusion: In vitro, solgel TiO2 with Ag and Degussa TiO2 with Ag both attenuated P. aeruginosa growth, but demonstrated no effect on S. aureus colonization. Further studies using alternative coating and incorporating UV light exposure are needed to identify their potential utility in reducing VAP.Keywords: ventilator-associated pneumonia, Degussa titanium dioxide, solgel titanium dioxide, quantitative culture

  17. Synthesis and Bactericidal Ability of TiO2 and Ag-TiO2 Prepared by Coprecipitation Method

    Directory of Open Access Journals (Sweden)

    Robert Liu

    2012-01-01

    Full Text Available Preparation of photocatalysts of TiO2 and Ag-TiO2 was carried out by coprecipitation method. The prepared photocatalysts were characterized by X-ray diffraction (XRD, SEM, EDX, and XRF analysis. The disinfection of E. coli, a model indicator organism for the safe water supply, was investigated by using TiO2 and Ag-TiO2 under different light sources. The treatment efficacy for the inactivation of E. coli would be UV/Ag-TiO2; visible/Ag-TiO2; dark/Ag-TiO2; UV (all 100% > UV/TiO2 (99% > visible/TiO2 (96% > dark/TiO2 (87% > visible (23% > dark (19%. The order of disinfection efficiency by their corresponding kinetic initial apparent rate constants, app, (min−1 would be UV/Ag-TiO2; visible/Ag-TiO2 (both 6.67 > UV (6.6 > dark/Ag-TiO2 (6.56 > UV/TiO2 (1.62 > visible/TiO2 (1.08 > dark/TiO2 (0.7 > visible (0.28 > dark (0.03. The application of TiO2 doped with silver strongly improved the ability of disinfection treatment. The study of mineralization of E. coli by measurement of TOC (total organic carbon removal percentage showed that the visible light may effectively be applied for the disinfection unit of water and wastewater treatment system by using photocatalysts of Ag-TiO2.

  18. Synthesis and Bactericidal Ability of TiO2 and Ag-TiO2 Prepared by Coprecipitation Method

    OpenAIRE

    Robert Liu; Wu, H. S.; Ruth Yeh; Lee, C Y; Yungtse Hung

    2012-01-01

    Preparation of photocatalysts of TiO2 and Ag-TiO2 was carried out by coprecipitation method. The prepared photocatalysts were characterized by X-ray diffraction (XRD), SEM, EDX, and XRF analysis. The disinfection of E. coli, a model indicator organism for the safe water supply, was investigated by using TiO2 and Ag-TiO2 under different light sources. The treatment efficacy for the inactivation of E. coli would be UV/Ag-TiO2; visible/Ag-TiO2; dark/Ag-TiO2; UV (all 100%) > UV/TiO2 (99%) > visib...

  19. Bactericidal Activity of Copper Oxide Nanocomposite/Bioglass for in Vitro Clindamycin Release in Implant Infections Due to Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Alijanian

    2016-08-01

    Full Text Available Background In recent years, bioactive bioceramics such as bioglass and hydroxyapatite (HA have been introduced as a remarkable development in the field of medicine due to their bio-adaptability, non-toxicity, and persistence, in vivo. They have many potential applications in the repair of bone defects and hence they have attracted significant interest from scholars. Objectives The aim of this study was to synthesize inorganic matrix CuO-based bioglasses and evaluate their antibacterial activity against aerobic bacterial infections in bone implants. Methods Nano-composite samples of silica-based bioactive glass, 60S BG with nano-powder CuO, were synthesized using the sol-gel method and then assessed with regard to their antibacterial properties against Staphylococcus aureus using well diffusion agar. The samples included BG58S (58%SiO2, 36%CaO, 6%P2O5, BG/10CuO (58%SiO2, 26%CaO, 6%P2O5, 10%CuO, and BG/20CuO (48%SiO2, 26%CaO, 6%P2O5, 20%CuO. To evaluate their bioactivity, the prepared samples of BG/20CuO, BG/10CuO, and BG58S were immersed in simulated body fluids (SBF. The surface morphology and structure of the samples before and after immersion in the SBF were characterized using scanning electron microscopy (SEM and Fourier transform infrared (FTIR, respectively. Then, the BG/20CuO and BG/10CuO samples were loaded in clindamycin, an antibiotic widely used in the treatment of osteomyelitis, and their release profiles were studied in phosphate buffer solution. Results It was observed that the growth inhibition zone increased through clindamycin release due to the increasing CuO percentage in the nanocomposite of bioactive glass. The bioactivity of the nanocomposite/bioglass with CuO was superior to that of bioglass alone. In this study, the BG/20CuO sample showed a sustained release of clindamycin, which is sufficient for a drug delivery system. Conclusions Increasing the Cu nanoparticles in bioactive glass samples leads to the release of Cu2+, which has a positive effect on the antibacterial mechanism, as well as decreasing the cultured Staphylococcus colonies found on the bioglasses. Therefore, it seems that the nanocomposite/bioglass of CuO is a promising option for aerobic bacterial inhibitor systems in common bone implant infections.

  20. Visible light induced bactericidal and photocatalytic activity of hydrothermally synthesized BiVO4 nano-octahedrals.

    Science.gov (United States)

    Sharma, Rishabh; Uma; Singh, Sonal; Verma, Ajit; Khanuja, Manika

    2016-09-01

    In the present work, monoclinic bismuth vanadate (m-BiVO4) nanostructures have been synthesized via simple hydrothermal method and employed for visible light driven antimicrobial and photocatalytic activity. Morphology (octahedral) and size (200-300nm) of the m-BiVO4 are studied using transmission electron microscopy (TEM). The crystal structure of m-BiVO4 (monoclinic scheelite structure) is confirmed by high resolution-TEM (HRTEM) and X-ray diffraction (XRD) studies. The band gap of m-BiVO4 was estimated to be ca. 2.42eV through Kubelka-Munk function F(R∞) using diffuse reflectance spectroscopy (DRS). Antimicrobial action of m-BiVO4 is anticipated by (i) shake flask method, (ii) MTT [3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide] assay for cytotoxicity. SEM analysis has been carried on Escherichia coli (E.coli) before and after treatment with nanostructure materials to reveal the mechanism underlying the antimicrobial action. Antimicrobial activity is studied as a function of m-BiVO4 concentration viz. 20, 40, 60 and 80ppm. The bacterial growth is decreased 80% to 96%, with the increase in m-BiVO4 concentration from 20ppm to 80ppm, respectively, in 2h. Photocatalytic activity and rate kinetics of m-BiVO4 nanostructures have been studied as a function of time on methylene blue (MB) dye degradation which is one of the waste products of textile industries and responsible for water pollution.

  1. Bactericidal, structural and morphological properties of ZnO2 nanoparticles synthesized under UV or ultrasound irradiation

    Science.gov (United States)

    Colonia, R.; Solís, J. L.; Gómez, M.

    2014-03-01

    Nanoparticles of ZnO2 were synthesized by a sol-gel method using Zn(CH3COO)2 and H2O2 in an aqueous solution exposed to either ultraviolet (UV) or ultrasound irradiation. X-ray diffraction and scanning electron microscopy showed that the nanostructures consisted of spherical blackberry-like clusters. Nanoparticles fabricated by using UV irradiation had smaller sizes and narrower size distributions than nanoparticles prepared by using ultrasound. Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used as test microorganisms, and the antibacterial activity of the ZnO2 nanoparticles was studied by use of the well diffusion agar bacteriological test. ZnO2 nanoparticles synthetized using UV had the best antibacterial properties. The inhibition zone was largest for B. subtilis but was present also for S. aureus and E. coli.

  2. Screening of antimicrobials from Caribbean sea animals and isolation of bactericidal proteins from the littoral mollusk Cenchritis muricatus.

    Science.gov (United States)

    López-Abarrategui, Carlos; Alba, Annia; Lima, Loiane A; Maria-Neto, Simone; Vasconcelos, Ilka M; Oliveira, Jose T A; Dias, Simoni C; Otero-Gonzalez, Anselmo J; Franco, Octavio L

    2012-05-01

    Marine organisms represent approximately half of the world's biodiversity by virtue of the sea being an immense reservoir of bioactive molecules. Here, antimicrobial crude extract activities of different marine invertebrates from the Caribbean Sea were evaluated. One of the most active, crude extracts was that marine snail Cenchritis muricatus, it was capable of totally inhibiting the development of Staphylococcus aureus and also showed a growth inhibition of 95.9% in Escherichia coli. Aiming to isolate molecules that confirm antimicrobial activity, the crude extract was purified by reversed-phase HPLC C-18 chromatography. Thereafter, one of the obtained fractions preserved this antibacterial activity. Furthermore, SDS-PAGE analysis (15%) showed the presence of two proteins of molecular masses with approximately 10 and 15 kDa, respectively. The first 19 amino acids of both proteins were sequenced by using Edman degradation, yielding unidentified primary structures compared against sequences deposited at NCBI databank. This is the first report of antibacterial proteins isolated from the mollusk Cenchritis muricatus and these proteins could be used as antibiotic alternatives in the aquacultural industry, as well as in agricultural or biomedical research.

  3. [Bactericid and fungicid polymers in dentistry. Polyethyleneimine, a new effective antibacterial and antifungal cationic polymer and its dental application].

    Science.gov (United States)

    Géczi, Zoltán; Kispélyi, Barbara; Pál, Károly; Hermann, Péter

    2016-06-01

    In the past years antibacterial and antifungal polymers had become the focus of medical research. Polyethylenimine (PEI) and poliamidoamin had been proven the most effective polymers. The data shown in this short review discuss the chemical structure, pharmacological effects and medical use of PEI. Report in the international literature only gives examples of experimental dental appliance of PEI in sealers and filling materials. Because of the growing interest in the subject of PEI we find it important to inform the domestic dental society of cationic polymers.

  4. Bactericidal activity of an imidazo[1, 2-a]pyridine using a mouse M. tuberculosis infection model.

    Directory of Open Access Journals (Sweden)

    Yong Cheng

    Full Text Available Tuberculosis remains a global threat due in part to the long treatment regimen and the increased prevalence of drug resistant M. tuberculosis strains. Therefore, new drug regimens are urgently required to combat this deadly disease. We previously synthesized and evaluated a series of new anti-tuberculosis compounds which belong to the family of imidazo[1,2-a]pyridines. This family of compounds showed low nM MIC (minimal inhibitory concentration values against M. tuberculosis in vitro. In this study, a derivative of imidazo[1,2-a]pyridines, (N-(4-(4-chlorophenoxybenzyl-2,7-dimethylimidazo[1,2-a]pyridine-3-carboxamide (ND-09759, was selected as a promising lead compound to determine its protective efficacy using a mouse infection model. Pharmacokinetic analysis of ND-09759 determined that at a dosage of 30 mg/kg mouse body weight (PO gave a maximum serum drug concentration (Cmax of 2.9 µg/ml and a half-life of 20.1 h. M. tuberculosis burden in the lungs and spleens was significantly decreased in mice treated once daily 6 days per week for 4-weeks with ND-09759 compared to untreated mice and this antibiotic activity was equivalent to isoniazid (INH and rifampicin (RMP, two first-line anti-TB drugs. We observed slightly higher efficacy when using a combination of ND-09759 with either INH or RMP. Finally, the histopathological analysis revealed that infected mice treated with ND-09759 had significantly reduced inflammation relative to untreated mice. In conclusion, our findings indicate ND-09759 might be a potent candidate for the treatment of active TB in combination with current standard anti-TB drugs.

  5. New RP-HPLC Method for Separation of Naja haje haje Venom and Studies of its Bactericidal Effect

    Directory of Open Access Journals (Sweden)

    Gâz Florea Şerban Andrei

    2016-03-01

    Full Text Available Background: Snake venom is a complex mixture of biologically active substances. Some peptides and proteins from snake have already demonstrated their therapeutically potential. The venom of Naja haje, an Elapidae member, has been analyzed from this point of view. Understanding the fully biochemical role of its enzymes has determined the scientists to find new separation and identification methods.

  6. Novel synergistic approach to exploit the bactericidal efficacy of commercial disinfectants on the biofilms of Salmonella enterica serovar Typhimurium.

    Science.gov (United States)

    Singla, Richu; Goel, Honey; Ganguli, Abhijit

    2014-07-01

    Combined effect of malic acid and ozone as sanitizer to inhibit the biofilm formation by Salmonella typhimurium on different food contact surfaces was investigated in this study. Different surfaces used in food industry including PVC pipes, polyethylene bags, plastic surfaces and fresh produce were analyzed for the biofilm formation by S. typhimurium ST1 and ST2. Malic acid alone was not able to inhibit biofilm formation in all the samples. However, combination of malic acid with ozone reduced the biofilm formation on plastic bags as well as on PVC pipes suggesting as an effective disinfectant for food contact surfaces. Five- and six-fold reduction in biofilm formation was observed in microtitre plates after 20 h and 40 h. Scanning electron micrographs of carrot and turnip showed control over the biofilms. Malic acid as sanitizer in food industry was effective for the complete inhibition of biofilm in carrot and other food contact surfaces, besides this, combined sanitizer (malic acid and ozone) was effective in turnip. Biofilms in food-processing industries can survive even after the sanitizer treatment and may represent reservoirs of product contamination leading to subsequent spoilage and/or food safety risks.

  7. Synthesis and characterization of silver nanoparticles from Alpinia calcarata by Green approach and its applications in bactericidal and nonlinear optics

    Science.gov (United States)

    Pugazhendhi, S.; Kirubha, E.; Palanisamy, P. K.; Gopalakrishnan, R.

    2015-12-01

    Development of green route for the synthesis of nanoparticles with plant extracts plays a very important role in nanotechnology without any toxicity chemicals. Herein we report a new approach to synthesize silver nanoparticles (AgNPs) using aqueous extract of Alpinia calcarata root as a reducing as well as stabilizing agent. The crystal structure and purity of the synthesized AgNPs were studied using Powder X-ray Diffraction analysis. The Surface Plasmon Resonance bands of synthesized silver nanoparticles have been obtained and monitored using UV-Visible spectrum. The morphologies of the AgNPs were analyzed using High resolution transmission electron microscopy (HRTEM). The elements present in the A. calcarata extract were determined by the inductively coupled plasma-optical emission Spectrometry (ICP-OES) and Fourier transform infrared spectroscopy (FTIR). Silver nanoparticles from A. calcarata possess very good antimicrobial activity which was confirmed by resazurin dye reduction assay method and thus it is a potential source of antimicrobial agent. The synthesized Ag nanoparticles exhibit good optical nonlinearity and the nonlinear optical studies have been carried out by Z-scan technique.

  8. Formation of hydroxyl radicals contributes to the bactericidal activity of ciprofloxacin against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, Peter Ø.; Briales, Alejandra; Brochmann, Rikke Prejh;

    2014-01-01

    induction of cytotoxic hydroxyl radicals (OH˙) during antibiotic treatment of planktonically grown cells may contribute to action of the commonly used antibiotic ciprofloxacin on P. aeruginosa biofilms. For this purpose, WT PAO1, a catalase deficient ΔkatA and a ciprofloxacin resistant mutant of PAO1 (gyr...

  9. Silver-loaded nanotubular structures enhanced bactericidal efficiency of antibiotics with synergistic effect in vitro and in vivo

    Science.gov (United States)

    Xu, Na; Cheng, Hao; Xu, Jiangwen; Li, Feng; Gao, Biao; Li, Zi; Gao, Chenghao; Huo, Kaifu; Fu, Jijiang; Xiong, Wei

    2017-01-01

    Antibiotic-resistant bacteria have become a major issue due to the long-term use and abuse of antibiotics in treatments in clinics. The combination therapy of antibiotics and silver (Ag) nanoparticles is an effective way of both enhancing the antibacterial effect and decreasing the usage of antibiotics. Although the method has been proved to be effective in vitro, no in vivo tests have been carried out at present. Herein, we described a combination therapy of local delivery of Ag and systemic antibiotics treatment in vitro in an infection model of rat. Ag nanoparticle-loaded TiO2 nanotube (NT) arrays (Ag-NTs) were fabricated on titanium implants for a customized release of Ag ion. The antibacterial properties of silver combined with antibiotics vancomycin, rifampin, gentamicin, and levofloxacin, respectively, were tested in vitro by minimum inhibitory concentration (MIC) assay, disk diffusion assay, and antibiofilm formation test. Enhanced antibacterial activity of combination therapy was observed for all the chosen bacterial strains, including gram-negative Escherichia coli (ATCC 25922), gram-positive Staphylococcus aureus (ATCC 25923), and methicillin-resistant Staphylococcus aureus (MRSA; ATCC 33591 and ATCC 43300). Moreover, after a relative short (3 weeks) combinational treatment, animal experiments in vivo further proved the synergistic antibacterial effect by X-ray and histological and immunohistochemical analyses. These results demonstrated that the combination of Ag nanoparticles and antibiotics significantly enhanced the antibacterial effect both in vitro and in vivo through the synergistic effect. The strategy is promising for clinical application to reduce the usage of antibiotics and shorten the administration time of implant-associated infection.

  10. Cinnamon zeylanicum bark extract and powder mediated green synthesis of nano-crystalline silver particles and its bactericidal activity.

    Science.gov (United States)

    Sathishkumar, M; Sneha, K; Won, S W; Cho, C-W; Kim, S; Yun, Y-S

    2009-10-15

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The present study reports the synthesis of silver (Ag) nanoparticles from silver precursor using the bark extract and powder of novel Cinnamon zeylanicum. Water-soluble organics present in the plant materials were mainly responsible for the reduction of silver ions to nano-sized Ag particles. TEM and XRD results confirmed the presence of nano-crystalline Ag particles. The pH played a major role in size control of the particles. Bark extract produced more Ag nanoparticles than the powder did, which was attributed to the large availability of the reducing agents in the extract. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The EC(50) value of the synthesized nanoparticles against Escherichia coli BL-21 strain was 11+/-1.72 mg/L. Thus C. zeylanicum bark extract and powder are a good bio-resource/biomaterial for the synthesis of Ag nanoparticles with antimicrobial activity.

  11. The use of water and ice with bactericide to prevent onboard and onshore spoilage of refrigerated megrim (Lepidorhombus whiffiagonis).

    Science.gov (United States)

    Pastoriza, Laura; Bernárdez, Marta; Sampedro, Gabriel; Cabo, Marta L; Herrera, Juan J R

    2008-09-01

    This study investigates the effectiveness of ozonated water and flake ice (combined Petfrost system) to increase the quality and stability of fresh megrim on fishing boats. The captured fish were washed, placed in plastic boxes, covered with flake ice and refrigerated at 2°C for up to 2-weeks onboard and, thereafter, for 11 days onshore. The experiments employed sterile, filtered and ozonated water at a concentration of 2ppm for washing the fish and making the flake ice. The results are compared with samples from a traditional treatment consisting of water and flake ice of marine origin. Fish were caught in four different hauls, which took 14, 12, 8 and 3 days in being landed. Subsequently, fish were stored for 1, 5, 7 and 11 days at 3°C. The different treatments were evaluated using sensory, microbiological and chemical techniques. Fish treated with ozone always showed the best quality. Megrim treated with ozone was still suitable for consumption after 14 days on board, and megrim stored for 12, 8 and 3 days on board could be stored for a further five days in the ice state once landed with an acceptable quality. In contrast, control fish were not suitable for consumption if stored for longer than three days on board.The results indicate that treatment with water and ice flakes made from sterile and ozonated water maintains the quality of fresh megrim onboard fishing boats and upon arrival onshore.

  12. Relating the Surface Properties of Superparamagnetic Iron Oxide Nanoparticles (SPIONs to Their Bactericidal Effect towards a Biofilm of Streptococcus mutans.

    Directory of Open Access Journals (Sweden)

    Taraneh Javanbakht

    Full Text Available This study was designed to determine the effects of superparamagnetic iron oxide nanoparticles (SPIONs on the biological activity of a bacterial biofilm (Streptococcus mutans. Our hypothesis was that the diffusion of the SPIONs into biofilms would depend on their surface properties, which in turn would largely be determined by their surface functionality. Bare, positively charged and negatively charged SPIONs, with hydrodynamic diameters of 14.6 ± 1.4 nm, 20.4 ± 1.3 nm and 21.2 ± 1.6 nm were evaluated. Time-of-flight secondary ion mass spectrometry (TOF-SIMS and electrophoretic mobility (EPM measurements were used to confirm that carboxylic functional groups predominated on the negatively charged SPIONS, whereas amine functional groups predominated on the positively charged particles. Transmission electron microscopy (TEM showed the morphology and sizes of SPIONs. Scanning electron microscopy (SEM and EPM measurements indicated that the surfaces of the SPIONs were covered with biomolecules following their incubation with the biofilm. Bare SPIONs killed bacteria less than the positively charged SPIONs at the highest exposure concentrations, but the toxicity of the bare and positively charged SPIONs was the same for lower SPION concentrations. The positively charged SPIONs were more effective in killing bacteria than the negatively charged ones. Nonetheless, electrophoretic mobilities of all three SPIONs (negative, bare and positively charged became more negative following incubation with the (negatively-charged biofilm. Therefore, while the surface charge of SPIONS was important in determining their biological activity, the initial surface charge was not constant in the presence of the biofilm, leading eventually to SPIONS with fairly similar surface charges in situ. The study nonetheless suggests that the surface characteristics of the SPIONS is an important parameter controlling the efficiency of antimicrobial agents. The analysis of the CFU/mL values shows that the SPIONs have the same toxicity on bacteria in solution in comparison with that on the biofilm.

  13. Comparative analyses of the bactericidal activity of snake venoms%蛇毒抗菌的比较性研究

    Institute of Scientific and Technical Information of China (English)

    李妲; 孙明忠; 郭春梅; 彭博雅; 刘淑清

    2013-01-01

    目的 研究蛇毒粗毒的抗菌作用,并比较不同蛇毒对不同细菌的抑制效果.方法 采用抑菌环法测定蛇岛蝮、江浙蝮和短尾蝮蛇毒粗毒对金黄色葡萄球菌、枯草芽孢杆菌、大肠埃希菌、铜绿假单胞菌以及白色念珠菌的抗菌作用,比较不同蛇毒粗毒的抗菌效果;加入过氧化氢酶(catalase),考察蛇毒抗菌作用的变化.结果 (1)3种蛇毒粗毒对5种细菌均呈现不同程度的抑制作用.(2)3种蛇毒粗毒对5种细菌的抑制作用大小依次为:金黄色葡萄球菌>白色念珠菌>大肠埃希菌或铜绿假单胞菌>枯草芽孢杆菌.(3)加入catalase后,蛇毒的抗菌作用明显减弱.结论 (1)3种蛇毒粗毒均具有一定的抗菌作用,并具有明显抑菌选择性.(2)3种蛇毒的抗菌效果不同,蛇岛蝮蛇抗菌作用最强.(3) catalase能显著降低蛇毒的抗菌活性,表明L-氨基酸氧化酶是蛇毒起抗菌作用的主要成分.%Objective To measure and compare the anti-bacterial activity of crude snake venoms against different bacterium strains.Methods The bacteria-inhibiting ring method was applied to measure the anti-bacterial effects of the snake venoms of Gloydius shedaoensis,Agkistrodon halys Pallas and Gloydius brevicaudus on the growths of the bacterium strains of Staphyloccocus aureus,Bacillus subtilis,Escherichia coli,Pseudomonas aeruginosa and Candida albicans.The anti-bacterial activities of different crude snake venoms were then compared.The effect of the addition of catalase was also compared.Results (1) The three crude snake venoms showed varied inhibitory effects on the five types of bacterium tested in current work.(2) Basically,the snake venoms showed the strongest inhibitory effect against Staphyloccocus aureus,followed by Candida albicans,Escherichia coli or Pseudomonas acruginosa and Bacillus subtilis.(3) In the presence of catalase,the anti-bacterial effect of Gloydius shedaoensis vemon was significantly suppressed.Conclusions (1) The three snake venoms all showed anti-bacterial activities,with varied anti-bacterial selectivity.(2) Among them,Gloydius shedaoensis vemon showed the highest anti-bacterial activity.(3) The addition of catalase dramatically decreased the anti-bacterial activity of crude snake vemon,which indicates that L-amino acid oxidase (LAAO) is the critical component responsible for the anti-bacterial activity of snake venoms.

  14. In vitro bactericidal efficacy of atmospheric-pressure plasma jet on titanium-based implant infected with Staphylococcus aureus

    Science.gov (United States)

    Park, Young-Ouk; Lee, Chang-Min; Kim, Myung-Sun; Jung, Sang-Chul; Yang, Seong-Won; Kook, Min-Suk; Kim, Byung-Hoon

    2017-01-01

    Staphylococcus aureus is a representative of gram-positive bacteria that causes skin infection, respiratory diseases, and burned tissue infections. The aim of this study was to evaluate the sterilizing efficiency of an atmospheric-pressure plasma jet (APPJ) on S. aureus adhered on a titanium surface. During the APPJ sterilization, the plasma gases used were Ar, Ar+N2, and Ar+O2. With increasing APPJ treatment time, the viability of S. aureus decreased. The addition of O2 gas to Ar gas resulted in a higher sterilizing efficiency than the addition of other groups. Plasma exposure induced bacterial oxidative stress, and it was confirmed that the cell membrane was seriously damaged by the production of reactive oxygen species. Our finding suggests that the APPJ is an effective tool for clinical antimicrobial therapy.

  15. Meningococcal Serogroup B Bivalent rLP2086 Vaccine Elicits Broad and Robust Serum Bactericidal Responses in Healthy Adolescents

    DEFF Research Database (Denmark)

    Vesikari, Timo; Østergaard, Lars Jørgen; Diez-Domingo, Javier

    2015-01-01

    ≥1:8 after 3 doses ranged from 91.7% to 95.0%, 98.9% to 99.4%, 88.4% to 89.0%, and 86.1% to 88.5% for MnB test strains expressing vaccine--heterologous fHBP variants A22, A56, B24, and B44, respectively. After 2 doses, responses ranged from 90.8% to 93.5%, 98.4% to 100%, 69.1% to 81.1%, and 70...

  16. Colloidal titania-silica-iron oxide nanocomposites and the effect from silica thickness on the photocatalytic and bactericidal activities

    Science.gov (United States)

    Chanhom, Padtaraporn; Charoenlap, Nisanart; Tomapatanaget, Boosayarat; Insin, Numpon

    2017-04-01

    New types of colloidal multifunctional nanocomposites that combine superparamagnetic character and high photocatalytic activity were synthesized and investigated. The superparamagnetic nanocomposites composed of anatase titania, silica, and iron oxide nanoparticles (TSI) were synthesized using thermal decomposition method followed by microemulsion method, without calcination at high temperature. Different techniques including X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize and confirm the structure of the nanocomposites. These nanocomposites showed high photocatalytic activity when used in the photodegradation of methylene blue under irradiation with a black light lamp. Moreover, the nanocomposites exhibited high antibacterial properties. From our study, the nanocomposites can be useful in various applications such as removal of pollutants with readily separation from the environment using an external magnetic field. These composites could effectively photo-degrade the dye at least three cycles without regeneration. The effects of silica shell thickness on the photocatalytic activity was investigated, and the thickness of 6 nm of the silica interlayer is enough for the inhibition of electron translocation between titania and iron oxide nanoparticles and maintaining the efficiency of photocatalytic activity of titania nanoparticles.

  17. Ex-vivo assessment of meningococcal resistance to natural immunity: serum bactericidal assays versus whole- blood assay

    Directory of Open Access Journals (Sweden)

    Nosratollah Saeed Adeli

    2009-01-01

    Full Text Available 1, 2,1 2 (Received 4 Dec, 2008; Accepted 14 Feb, 2009AbstractBackground and purpose: Literature review indicates that antibiotic resistance of bacteria may be associated with the resistance to host natural immunity. In the previous study we found that: all meningococcal isolates of meningitis cases are less sensitive to typical anti-meningococcal antibiotics. In present study, the association of the above characters was analyzed in an ex-vivo “case-control” study.Materials and methods: A randomized controlled trial compared effect two dietary treatments (low glycemic index & low fat in 46 adults, ages 18-55 years old, BMI >27,who proceed to motahary clinic in shiraz, Iran. Body weight, BMI, WHR (waist/hip ratio, fast and post-prandial Plasma lipid profile (Triacylglycerol, total Cholesterol, LDL-C, HDL-C concentration level of obese women measured at the beginning and at the end 6 weeks.Results: The resistance of both groups against selected sera were similar in the ratio 1:2- by SIC and SBC methods. The growth of “test” and “control” groups in the pooled sera were stopped at the ratios 1:512 and 1:1024 respectively. In SBA the population of “test” and “control” groups decreased in parallel to each other. However, the invasive (test meningococcal strains established slower reduction in WBA.Conclusion: Studies on the correlation between antibiotic resistance of bacteria and the resistance to the natural immunity have ended with different results. According to our experience, it seems that for ex- vivo investigation of natural immunity against meningococci the WBA is more reliable. J Mazand Univ Med Sci 2009; 19(68:48-57 (Persian

  18. Efecto bactericida del láser de diodo en periodoncia Bactericidal effects of diode laser in periodontology

    OpenAIRE

    G Caccianiga; Urso, E.; R Monguzzi; Gallo, K.; G. Rey

    2008-01-01

    El láser en odontología, gracias a su capacidad antibacteriana, hemostática y de menor sintomatología operatoria, encuentra un amplio campo de aplicación en el ámbito de la terapia periodontal. En este estudio ha sido probada la eficacia de un protocolo que prevé el utilizo asociado de irradiación láser y de agua oxigenada con el fin de reducir a carga bacteriana de cepas comúnmente presentes en las bolsas periodontales activas y resistentes a la acción bactericida de solamente la irradiación...

  19. Naphthalimides Selectively Inhibit the Activity of Bacterial, Replicative DNA Ligases and Display Bactericidal Effects against Tubercle Bacilli

    Directory of Open Access Journals (Sweden)

    Malgorzata Korycka-Machala

    2017-01-01

    Full Text Available The DNA ligases, enzymes that seal breaks in the backbones of DNA, are essential for all organisms, however bacterial ligases essential for DNA replication use β-nicotinamide adenine dinucleotide as their co-factor, whereas those that are essential in eukaryotes and viruses use adenosine-5′-triphosphate. This fact leads to the conclusion that NAD+-dependent DNA ligases in bacteria could be targeted by their co-factor specific inhibitors. The development of novel alternative medical strategies, including new drugs, are a top priority focus areas for tuberculosis research due to an increase in the number of multi-drug resistant as well as totally drug resistant tubercle bacilli strains. Here, through the use of a virtual high-throughput screen and manual inspection of the top 200 records, 23 compounds were selected for in vitro studies. The selected compounds were evaluated in respect to their Mycobacterium tuberculosis NAD+ DNA ligase inhibitory effect by a newly developed assay based on Genetic Analyzer 3500 Sequencer. The most effective agents (e.g., pinafide, mitonafide inhibited the activity of M. tuberculosis NAD+-dependent DNA ligase A at concentrations of 50 µM. At the same time, the ATP-dependent (phage DNA LigT4 was unaffected by the agents at concentrations up to 2 mM. The selected compounds appeared to also be active against actively growing tubercle bacilli in concentrations as low as 15 µM.

  20. Tin Oxide-Silver Composite Nanomaterial Coating for UV Protection and Its Bactericidal Effect on Escherichia coli (E. coli

    Directory of Open Access Journals (Sweden)

    Gil Nonato C. Santos

    2014-05-01

    Full Text Available SnO2-Ag composite nanomaterials of mass ratio 1:4, 2:3, 3:2 and 4:1 were fabricated and tested for toxicity to E. coli using the pour-plate technique. The said nanomaterials were mixed with laminating fluid and then coated on glass slides. The intensity of UVA transmitted through the coated glass slides was measured. Results revealed that the 1:4 ratios of SnO2-Ag composite nanomaterials have the optimum toxicity to E. coli. Furthermore, the glass slides coated with SnO2 nanomaterial showed the lowest intensity of transmitted UVA.

  1. Bactericidal effect of bovine lactoferrin, LFcin, LFampin and LFchimera on antibiotic-resistant Staphylococcus aureus and Escherichia coli

    NARCIS (Netherlands)

    Flores-Villaseñor, H.; Canizalez-Román, A.; Reyes-Lopez, M.; Nazmi, K.; de la Garza, M.; Zazueta-Beltrán, J.; León-Sicairos, N.; Bolscher, J.G.M.

    2010-01-01

    Increased prevalence of antibiotic-resistant bacteria has become a major threat to the health sector worldwide due to their virulence, limited therapeutic options and distribution in both hospital and community settings. Discovery and development of new agents to combat antibiotic-resistant bacteria

  2. Characterization and Potential Environmental Implications of Select Cu-Based Fungicides and Bactericides Employed in U.S. Markets

    Science.gov (United States)

    This exploratory study aimed to examine the extent and mineral speciation of nanosized Cu in two fungicide products (A and B) available in the U.S. markets. Electron microcopy results demonstrated the presence of spherical and polydisperse <100 nm Cu particles in product B. Oth...

  3. Bactericidal activity of LFchimera is stronger and less sensitive to ionic strength than its constituent lactoferricin and lactoferrampin peptides

    NARCIS (Netherlands)

    J.G.M. Bolscher; R. Adão; K. Nazmi; P.A.M. van den Keijbus; W. van 't Hof; A. van Nieuw Amerongen; M. Bastos; E.C.I. Veerman

    2009-01-01

    The innate immunity factor lactoferrin harbours two antimicrobial moieties, lactoferricin and lactoferrampin, situated in close proximity in the N1 domain of the molecule. Most likely they cooperate in many of the beneficial activities of lactoferrin. To investigate whether chimerization of both pep

  4. Bactericidal effect of bovine lactoferrin and synthetic peptide lactoferrin chimera in Streptococcus pneumoniae and the decrease in luxS gene expression by lactoferrin

    NARCIS (Netherlands)

    N. León-Sicairos; U.A. Angulo-Zamudio; J.E. Vidal; C.A. López-Torres; J.G.M. Bolscher; K. Nazmi; R. Reyes-Cortes; M. Reyes-López; M. de la Garza; A. Canizalez-Román

    2014-01-01

    Streptococcus pneumoniae (pneumococcus) is responsible for nearly one million child deaths annually. Pneumococcus causes infections such as pneumonia, otitis media, meningitis, and sepsis. The human immune system includes antibacterial peptides and proteins such as lactoferrin (LF), but its activity

  5. Bactericidal Activity of Aqueous Acrylic Paint Dispersion for Wooden Substrates Based on TiO2 Nanoparticles Activated by Fluorescent Light

    Directory of Open Access Journals (Sweden)

    Diana Di Gioia

    2013-08-01

    Full Text Available The photocatalytic effect of TiO2 has great potential for the disinfection of surfaces. Most studies reported in the literature use UV activation of TiO2, while visible light has been used only in a few applications. In these studies, high concentrations of TiO2, which can compromise surface properties, have been used. In this work, we have developed an acrylic-water paint dispersion containing low TiO2 content (2 vol % for the inactivation of microorganisms involved in hospital-acquired infections. The nanoparticles and the coating have been characterized using spectroscopic techniques and transmission electron microscopy, showing their homogenous dispersion in the acrylic urethane coating. A common fluorescent light source was used to activate the photocatalytic activity of TiO2. The paint dispersion showed antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The coating containing the TiO2 nanoparticles maintained good UV stability, strong adhesion to the substrate and high hardness. Therefore, the approach used is feasible for paint formulation aimed at disinfection of healthcare surfaces.

  6. Oral Immunization of Rabbits with S. enterica Typhimurium Expressing Neisseria gonorrhoeae Filamentous Phage Φ6 Induces Bactericidal Antibodies Against N. gonorrhoeae

    OpenAIRE

    Andrzej Piekarowicz; Aneta Kłyż; Michał Majchrzak; Stein, Daniel C.

    2016-01-01

    All Neisseria gonorrhoeae strains whose DNA sequences have been determined possess filamentous phage DNA sequences. To ascertain if phage encoded proteins could form the basis of a gonococcal vaccine, rabbits were orally infected with S. enterica Typhimurium strain χ3987 harboring phagemid NgoΦ6 fm. The elicited sera contained large quantities of anti-phage IgG and IgA antibodies that bound to the surface of N. gonorrhoeae cells, as shown by indirect fluorescent analysis and flow cytometry. T...

  7. Antimycobacterial natural products from Moroccan medicinal plants: Chemical composition, bacteriostatic and bactericidal profile of Thymus satureioides and Mentha pulegium essential oils

    Directory of Open Access Journals (Sweden)

    Marwa Chraibi

    2016-10-01

    Conclusions: It is clearly evident from the results obtained that the Moroccan medicinal plants have great potential to be used as anti-tuberculosis agents. These findings may help scientists to undertake several research projects to discover useful natural product as new anti-tuberculosis drug.

  8. The Neisseria meningitidis Macrophage Infectivity Potentiator Protein Induces Cross-Strain Serum Bactericidal Activity and Is a Potential Serogroup B Vaccine Candidate ▿

    OpenAIRE

    Hung, Miao-Chiu; Salim, Omar; Williams, Jeannette N.; Heckels, John E.; Christodoulides, Myron

    2011-01-01

    A gene encoding a 29-kDa protein from Neisseria meningitidis serogroup B strain MC58 with homology to the macrophage infectivity potentiator (MIP) protein of Legionella pneumophila was cloned and expressed in Escherichia coli, and the purified soluble recombinant protein (rMIP) was used for immunization studies. Analysis of the predicted amino acid sequences of MIP from 13 well-characterized meningococcal strains, isolated from carriers or patients and differing in serogroup, serotype, and su...

  9. Evaluation of bactericidal activity of TiO2 photocatalysts: a comparative study of laboratory-made and commercial TiO2 samples

    Directory of Open Access Journals (Sweden)

    Uraiwan Sirimahachai

    2009-11-01

    Full Text Available Titanium dioxide photocatalysts were synthesized by sol-gel process, by varying the reaction conditions, acids, water content, and trivalent (Al, B dopants. The characterizations of products were determined by XRD, SEM, BET, and UV-vis spectroscopy. The samples were mainly amorphous with a small amount of anatase, rutile, or a mixture of anatase and rutile, with a crystallite sizes of about 5-10 nm. The antibacterial activity of the synthesized TiO2 samples were investigated qualitatively and semi-quantitatively. Five types of bacteria, Escherichia coli ATCC25922, Psudomonas aeruginosa ATCC27853,Bacillus subtilis BGA, Staphylococcus aureus ATCC25923, and methicillin-resistant S. aureus (MRSA DMST 2054, were used for the inactivation experiment employing the agar dilution method. All the synthesized samples showed inactivation activity with varying degree of efficiency. Two of them showed a much higher activity than Degussa P25.

  10. 一种纳米颗粒膜杀菌陶瓷的研究%Study on Bactericidal Ceramics of Nanocrystalline Film

    Institute of Scientific and Technical Information of China (English)

    雷闫盈; 余历军; 张秀成; 齐智涛

    2003-01-01

    本文采用均相沉积法在陶瓷表面制得均匀透明的多孔Ti02纳米颗粒膜材料.以盹M、XRD等方法对膜材料的结构、组成、晶粒大小、杀菌性能进行了研究.结果表明,膜材料为均匀的多孔锐钛型TiO2颗粒膜;Ti02颗粒大小在7~30nm范围;杀菌性能好,对金黄色葡萄球菌、大肠杆菌、白色念珠菌在30min内的杀菌率均达到90%以上.该膜材料可直接应用于陶瓷制成具有杀菌功能的陶瓷制品,其在水质消毒、污水处理、空气净化、环境保护等方面具有广阔的应用前景.

  11. In vivo bactericidal effect of Melaleuca alternifolia essential oil against Aeromonas hydrophila: Silver catfish (Rhamdia quelen) as an experimental model.

    Science.gov (United States)

    F Souza, Carine; Baldissera, Matheus D; A Vaucher, Rodrigo; Lopes, Leonardo Q S; Vizzotto, Bruno S; Raffin, Renata P; Santos, Roberto C V; L da Veiga, Marcelo; U M da Rocha, Maria Izabel; Stefani, Lenita M; Baldisserotto, Bernardo

    2016-09-01

    Aeromonas hydrophila is one of the main causative agent of high mortality and significative economic losses in aquaculture and has become increasingly resistant to conventional antibiotics. One feasible alternative to control and treat it is the use of essential oils. This study aimed to evaluate A. hydrophila susceptibility to tea tree oil (TTO-Melaleuca alternifolia) in vivo, and the effect of this treatment. In vivo tests were performed using silver catfish (Rhamdia quelen) as the experimental model. Silver catfish were treated with TTO at 25 and 50 μL/L for seven days before infection. After seven days, the fish were inoculated with A. hydrophila via intramuscularly. Treatment with TTO at 50 μL/L was able to extend longevity of infected fish, and showed 88% of therapeutic success, even though it did not show curative efficacy. TTO treatment was not toxic under these tested concentrations, since biomarkers of hepatic and renal functions were not affected, and the concentration of 50 μL/L was able to prevent increased levels of aspartate aminotransferase. There was no significative differences regarding hematological parameters (p < 0.05). Treatment with TTO 50 μL/L was able to reduce histopathological alterations usually caused by this type of bacteria in the gills, but it was unable to reduce hepatic histopathological alterations. Our results showed, for the first time, that TTO has high activity against A. hydrophila and proved to be a natural alternative to prevent and control this pathogen.

  12. Inhibition of C5a-induced inflammation with preserved C5b-9-mediated bactericidal activity in a human whole blood model of meningococcal sepsis.

    NARCIS (Netherlands)

    Sprong, T.; Brandtzaeg, P.; Fung, M.; Pharo, A.M.; Hoiby, E.A.; Michaelsen, T.E.; Aase, A.; Meer, J.W.M. van der; Deuren, M. van; Mollnes, T.E.

    2003-01-01

    The complement system plays an important role in the initial defense against Neisseria meningitidis. In contrast, uncontrolled activation in meningococcal sepsis contributes to the development of tissue damage and shock. In a novel human whole blood model of meningococcal sepsis, we studied the effe

  13. Bactericidal and virucidal activity of the alkalophilic P395D/L241V/T343A mutant of vanadium chloroperoxidase

    NARCIS (Netherlands)

    Renirie, R.; Dewilde, A.; Pierlot, C.; Wever, R.; Hober, D.; Aubry, J.-M.

    2008-01-01

    Aims: Vanadium chloroperoxidase and its directed evolution mutant P395D/L241V/T343A were investigated for their antibacterial and antiviral potential at slightly alkaline pH and at a H2O2 concentration that is low compared to current nonenzymatic formulations. Methods and Results: Two bacteria (the

  14. Altered susceptibility to the bactericidal effect of photocatalytic oxidation by TiO2 is related to colistin resistance development in Acinetobacter baumannii.

    Science.gov (United States)

    Tseng, Chun-Chieh; Tsai, Yun-Hsuan; Hu, Anren; Liou, Je-Wen; Chang, Kai-Chih; Chang, Hsin-Hou

    2016-10-01

    Multidrug-resistant Acinetobacter baumannii is a well-documented pathogen associated with hospital-acquired infections. In addition to multidrug resistance, A. baumannii can also become resistant to colistin, the antibiotic treatment of last resort, by the loss of the lipopolysaccharide from its outer membrane. Here, we demonstrate that the development of colistin resistance also increases the resistance of A. baumannii to titanium dioxide (TiO2) photocatalysis. Both colistin-sensitive A. baumannii (CSAB) and colistin-resistant A. baumannii (CRAB) were inactivated by TiO2 when irradiated by ultraviolet A (UV-A). The resistance of CRAB to TiO2 photocatalysis was 1.5 times higher than that of CSAB, as determined by either culture assay or quantification of leaked proteins after photocatalysis (p resistance of CRAB may be associated with a lack of sensitive targets and oxidative enzymes. This hypothesis was confirmed by antimicrobial assays with 25 mM hydrogen peroxide (H2O2) and 1.07 mM sodium hypochlorite (NaClO). CRAB was significantly more resistant to H2O2 and NaClO treatment than CSAB (p experiment. Therefore, the antibiotic resistance profiles of bacterial strains should be considered before the use of strains as indicators to represent sanitary quality after TiO2 photocatalysis.

  15. Bactericidal Effect of Extracts and Metabolites of Robinia pseudoacacia L. on Streptococcus mutans and Porphyromonas gingivalis Causing Dental Plaque and Periodontal Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Jayanta Kumar Patra

    2015-04-01

    Full Text Available The mouth cavity hosts many types of anaerobic bacteria, including Streptococcus mutans and Porphyromonas gingivalis, which cause periodontal inflammatory diseases and dental caries. The present study was conducted to evaluate the antibacterial potential of extracts of Robinia pseudoacacia and its different fractions, as well as some of its natural compounds against oral pathogens and a nonpathogenic reference bacteria, Escherichia coli. The antibacterial activity of the crude extract and the solvent fractions (hexane, chloroform, ethyl acetate and butanol of R. pseudoacacia were evaluated against S. mutans, P. gingivalis and E. coli DH5α by standard micro-assay procedure using conventional sterile polystyrene microplates. The results showed that the crude extract was more active against P. gingivalis (100% growth inhibition than against S. mutans (73% growth inhibition at 1.8 mg/mL. The chloroform and hexane fractions were active against P. gingivalis, with 91 and 97% growth inhibition, respectively, at 0.2 mg/mL. None of seven natural compounds found in R. pseudoacacia exerted an antibacterial effect on P. gingivalis; however, fisetin and myricetin at 8 µg/mL inhibited the growth of S. mutans by 81% and 86%, respectively. The crude extract of R. pseudoacacia possesses bioactive compounds that could completely control the growth of P. gingivalis. The antibiotic activities of the hexane and chloroform fractions suggest that the active compounds are hydrophobic in nature. The results indicate the effectiveness of the plant in clinical applications for the treatment of dental plaque and periodontal inflammatory diseases and its potential use as disinfectant for various surgical and orthodontic appliances.

  16. COMPOSITION AND BACTERICIDAL ACTIVITY AGAINST BENEFICIAL AND PATHOGENIC BACTERIA OF OREGANO ESSENTIAL OILS FROM FOUR CHEMOTYPES OF Origanum AND Lippia GENUS

    Directory of Open Access Journals (Sweden)

    L. Betancourt

    2012-01-01

    Full Text Available Diversos estudios demuestran la actividad antibacterial de distintos quimiotipos de aceites esenciales de orégano (OEO, carvacrol y timol, contra bacterias patógenas Gram positivas y Gram negativas, pero muy poca información está disponible sobre el efecto de los OEO en bacterias benéficas. El objetivo de este estudio fue comparar la composición y concentración mínima bactericida (CMB de OEO de quimiotipos del género Origanum: O. vulgare L. ssp. hirtum (OH, O. majorana (OM y O. vulgare L. (OL cultivados en Colombia, frente Lippia origanoides Kunth (LO nativo del Alto Pa-tía en Colombia y O. vulgare L. ssp. hirtum cultivado en Grecia (OG. Los OEO se ob-tuvieron por arrastre de vapor, la composición se determinó por cromatografía de gases acoplada a espectrometría de masas y la actividad antibacteriana mediante el método de dilución en caldo y cultivo en agar. Se evaluaron tres quimiotipos de OEO: OH y OG tipo-carvacrol, LO y OL tipo-timol y OM rico en compuestos sabinilo. Las variedades de orégano producidas bajo condiciones de invernadero a alta altitud mostraron un alto contenido de precursores. Un valor similar de concentración mínima bactericida contra Salmonella enteritidis (0.098 mg/mL fue observada para carvacrol, OH y LO. La más baja actividad bactericida contra las bacterias benéficas Lactobacillusacidophilusy Bifidobacterium breve fue observada para OM (6.25 mg/mL y LO (50 mg/mL, respectivamente. Estos resultados mostraron que LO, nativo de Colombia presentó un efecto antibacteriano comparable a OH y carvacrol contra enterobacterias patógenas y una baja actividad bactericida contra las bacterias benéficas. Estos resultados mostraron un efecto bactericida selectivo contra bacterias benéficas y patógenas de los quimiotiposOriganum ssp. y L. origanoides. Se comprobó un buen potencial de L. origanoides para uso como aditivo antimicrobiano para la salud humana y animal.

  17. Major liver resection results in a changed plasma amino acid pattern as reflected by a decreased Fischer ratio which improves by bactericidal/permeability increasing protein

    NARCIS (Netherlands)

    Nijveldt, RJ; Wiezer, MJ; Meijer, C; Prins, HA; Muller, MGS; Gouma, DJ; Teerlink, T; van Gulik, TM; Rinkes, IHMB; Tilanus, HW; van de Velde, CJH; Wiggers, T; Zoetmulder, FAN; Scotte, M; Cuesta, MA; Meijer, S; van Leeuwen, PAM

    2001-01-01

    Background/Aims: Major liver resection results in a high morbidity and mortality, and endotoxin plays a role in post-resection hepatic failure. Severe hepatic failure as seen in hepatitis and cirrhosis may be accompanied by hepatic encephalopathy and is characterized by a typical plasma amino acid p

  18. 新型杀菌剂磷酸铜的固相合成及表征%Solid State Synthesis and Characterization of New Bactericide Copper Phosphate

    Institute of Scientific and Technical Information of China (English)

    卢华军; 曾波; 罗康碧; 马庆文

    2007-01-01

    采用固相合成法,以Cu(Ⅱ)和PO43-为原料,在740℃反应1 h合成磷酸铜Cu3(PO4)2.使用化学分析、热重分析和XRD分析等方法对产物进行了表征.结果表明,能用高温固相合成法来制备磷酸铜Cu3(PO4)2.通过正交实验得到了最佳工艺条件:n[Cu(Ⅱ)]/n[PO43-]=1.51;温度740℃;反应时间1 h.

  19. Bactericidal action of carvacrol towards the food pathogen Bacillus cereus : A case study of a novel approach to mild food preservation

    NARCIS (Netherlands)

    Ultee, A.

    2000-01-01

    A new trend in food preservation is the use of mild preservation systems, instead of more severe techniques such as heating, freezing or addition of chemical preservatives. Carvacrol, a phenolic compound present in the essential oil fraction of oreganum and thyme, is known for its antimicrobial acti

  20. Bactericidal activities of parenteral antibiotics and genotype of penicillin-binding protein in Streptococcus pneumoniae and Haemophilus influenzae isolated from children's blood.

    Science.gov (United States)

    Sakata, Hiroshi

    2006-10-01

    A total of 16 isolates of Streptococcus pneumoniae and 18 isolates of Haemophilus influenzae were obtained from the blood of children admitted to the pediatric wards of hospitals in Hokkaido Kamikawa subprefecture between January 2003 and December 2005. The ages of the patients with S. pneumoniae or H. influenzae infection ranged from 2 months to 9 years and from 1 month to 4 years, respectively. The diagnoses of S. pneumoniae infection were as follows: pneumonia in 8 patients, occult bacteremia in 5 patients, and meningitis in 3 patients. The diagnoses of H. influenzae were: meningitis in 6 patients, pneumonia in 4 patients, occult bacteremia in 4 patients, epiglotitis in 2 patients, and facial cellulitis in 2 patients. Out of 16 S. pneumoniae isolates, penicillin-resistant strains with a mutation of 3 genes were observed in 7 children, and penicillin intermediate-resistant strains with a mutation of 1 or 2 genes were observed in 8 children. Out of 18 H. influenzae isolates, the beta-lactamase-negative ampicillin-resistant strain with a substitution of 2 points in the ftsI gene was revealed in 2 children, the beta-lactamase-negative ampicillin-resistant strain with a substitution of 1 point in the ftsI gene was observed in 4 children, the beta-lactamase-positive amoxicillin/clavulanic acid-resistant strain with blaTEM-1 and ftsI with 2 substitutions in the ftsI gene was observed in 3 children, and the beta-lactamase-positive ampicillin-resistant strain with blaTEM-1was not observed. The MBC90s of ampicillin, ceftriaxone, cefotaxime, meropenem, panipenem, and vancomycin against S. pneumoniae were 8 microg/ml, 1 microg/ml, 1 microg/ml 1 microg/ml, 0.25 microg/ml, and 0.5 microg/ml, respectively. Those of ampicillin, piperacillin, ceftriaxone, cefotaxime, meropenem, and panipenem against H. influenzae were >128 microg/ml, >128 microg/ml, 0.25 microg/mL, 1 microg/ml, 0.12 microg/ml, and 0.5 g/ml, respectively. It is suggest that the minimum bactricidal concentration (MBC) was dissociated from the minimum inhibitory concentration (MIC) in S. pneumoniae and H. influenzae with abnormal pbp genes.

  1. Research on toxicity of bactericide carbendazim to paramecium%杀菌剂多菌灵对草履虫的毒性研究

    Institute of Scientific and Technical Information of China (English)

    李霖; 王君; 刘俊; 顾庆龙; 顾小琴; 邱同和

    2010-01-01

    进行多菌灵对草履虫的急慢性毒性作用研究.结果表明:多菌灵溶液的浓度对草履虫的生长有极显著影响,浓度越高毒性作用越大.对草履虫的1 h急性毒性作用LC50为0.534 0 mg/L,最大无致死浓度为0.075 mg/L,最小全致死浓度为37.5 mg/L.回归分析结果,草履虫种群增长率和多菌灵溶液的浓度呈线性关系.慢性毒性作用显示,在低浓度条件下多菌灵对草履虫生殖有促进作用,在浓度0.075~2.400 mg/L范围内,浓度对数越小(即多菌灵浓度越小)种群增长率越大,说明在一定浓度范围内多菌灵可能具有环境内分泌干扰物效应.

  2. Biodegradable drug-eluting nanofiber-enveloped implants for sustained release of high bactericidal concentrations of vancomycin and ceftazidime: in vitro and in vivo studies.

    Science.gov (United States)

    Hsu, Yung-Heng; Chen, Dave Wei-Chih; Tai, Chun-Der; Chou, Ying-Chao; Liu, Shih-Jung; Ueng, Steve Wen-Neng; Chan, Err-Cheng

    2014-01-01

    We developed biodegradable drug-eluting nanofiber-enveloped implants that provided sustained release of vancomycin and ceftazidime. To prepare the biodegradable nanofibrous membranes, poly(D,L)-lactide-co-glycolide and the antibiotics were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. They were electrospun into biodegradable drug-eluting membranes, which were then enveloped on the surface of stainless plates. An elution method and a high-performance liquid chromatography assay were employed to characterize the in vivo and in vitro release rates of the antibiotics from the nanofiber-enveloped plates. The results showed that the biodegradable nanofiber-enveloped plates released high concentrations of vancomycin and ceftazidime (well above the minimum inhibitory concentration) for more than 3 and 8 weeks in vitro and in vivo, respectively. A bacterial inhibition test was carried out to determine the relative activity of the released antibiotics. The bioactivity ranged from 25% to 100%. In addition, the serum creatinine level remained within the normal range, suggesting that the high vancomycin concentration did not affect renal function. By adopting the electrospinning technique, we will be able to manufacture biodegradable drug-eluting implants for the long-term drug delivery of different antibiotics.

  3. Exploring a new phenomenon in the bactericidal response of TiO2 thin films by Fe doping: Exerting the antimicrobial activity even after stoppage of illumination

    Science.gov (United States)

    Naghibi, Sanaz; Vahed, Shohreh; Torabi, Omid; Jamshidi, Amin; Golabgir, Mohammad Hossein

    2015-02-01

    Antibacterial properties of Fe-doped TiO2 thin films prepared on glass by the sol-gel hot-dipping technique were studied. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, scanning probe microscopy and X-ray photoelectron spectroscopy. The photocatalytic activities were evaluated by measuring the decomposition rate of methylene blue under ultra violet and visible light. The antibacterial properties of the coatings were investigated against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisia and Aspergillus niger. The principle of incubation methods was also discussed. The results indicated that Fe doping of thin films eventuated in high antibacterial properties under visible light and this performance remained even after stoppage of illumination. This article tries to provide some explanation for this fact.

  4. Efecto bactericida del láser Nd: YAP. Estudio in vitro Bactericidal effects of Nd: YAP. An in vitro study

    OpenAIRE

    G Caccianiga; Urso, E.; R Monguzzi; Gallo, K.; G. Rey

    2007-01-01

    La utilización del láser en el ambiente odontológico está teniendo cada vez más difusión gracias al hecho que éste puede conciliar un elevado standard de confort para el paciente con la eficacia terapéutica. El presente estudio ha evaluado la eficacia bactericida de la radiación láser asociada al empleo del agua oxigenada respecto a cinco cepas bacterianas comúnmente presentes en las bolsas periodontales activas y resistentes al empleo separado del láser y del agua oxigenada. Las cinco bacter...

  5. 江汉油田注入水杀菌剂的筛选与应用%Selection and Application of Bactericides in Jianghan Oilfield Water Injection

    Institute of Scientific and Technical Information of China (English)

    陈晓丽

    2009-01-01

    油田注入水中硫酸盐还原菌、铁细菌、腐生菌是危害最大的细菌,这三种细菌特性各异,相互之间还存在一定的联系.杀菌剂的选用应保证对这三种细菌有较好的杀灭作用,并辅以正确的投加方法.

  6. Concentrations of lipopolysaccharide-binding protein, bactericidal/permeability-increasing protein, soluble CD14 and plasma lipids in relation to endotoxaemia in patients with alcoholic liver disease

    DEFF Research Database (Denmark)

    Schäfer, C.; Parlesak, Alexandr; Schütt, C.;

    2002-01-01

    There is increasing evidence that gut leakage in persons with chronic alcohol misuse leads to endotoxaemia, which might contribute to the development of alcoholic hepatitis or cirrhosis. In addition, it was recently shown that the endotoxin-binding capacity of whole blood is reduced...... in these patients. To analyse this phenomenon, we measured the concentration of functionally important endotoxin-binding plasma components which modify the action of endotoxin. In patients with minimal (n = 10), intermediate (n = 9), and cirrhotic alcoholic liver disease (n = 11), and healthy controls (n = 11......), plasma endotoxin was determined in a limulus assay. The concentration of lipoproteins was assessed by measuring apolipoproteins, the other factors were directly measured in immunoassays. In the entire group of alcoholics, endotoxin and the concentration of binding factors that are involved in the action...

  7. A Thermostable Salmonella Phage Endolysin, Lys68, with Broad Bactericidal Properties against Gram-Negative Pathogens in Presence of Weak Acids

    DEFF Research Database (Denmark)

    Oliveira, Hugo; Thiagarajan, Viruthachalam; Walmagh, Maarten;

    2014-01-01

    Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68) and demonstrates its potential antimicrobial effectiveness when combined...... with organic acids towards Gram-negative pathogens. Biochemical characterization reveals that Lys68 is more active at pH 7.0, maintaining 76.7% of its activity when stored at 4°C for two months. Thermostability tests showed that Lys68 is only completely inactivated upon exposure to 100°C for 30 min......, and circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species) in combination with the outer membrane permeabilizers EDTA, citric and malic acid...

  8. 电化学杀菌技术在水处理中的研究进展%Research Progress of Electrochemical Bactericidal Technology in Water Treatment

    Institute of Scientific and Technical Information of China (English)

    张化冰; 郦和生

    2014-01-01

    Electrochemicalbactericidaltechnologyis a new sterilization technology ,w hich is efficient ,cost -ef-fective and eco -friendly .It includes electrolytic active chlorine disinfection ,electrolytic hydroxyl radical dis-infection ,electrolytic ozone disinfection ,electrolytic hydrogen peroxide disinfection ,etc .This article summa-rizes the disinfection mechanism ,electrode material ,electrolytic process and characteristics .%指出了电化学杀菌是一种高效率、低成本、环境友好的新型杀菌技术,包括电解活性氯杀菌、电解· O H杀菌、电解O3杀菌、电解H2 O2杀菌等。对这4种电化学杀菌技术的杀菌机理、电极材料、电解工艺条件及特点进行了探讨。

  9. A Preliminary Bactericidal Effect Study of the GB Limited Bacterium from the Microwave Oven Tap Water%微波加热自来水对国标限定菌杀灭效果的初步研究

    Institute of Scientific and Technical Information of China (English)

    黄意; 吴次南; 周碧君; 陈亮

    2011-01-01

    在同一功率下对微波炉和电炉效率进行了对比.结果表明:微波加热实验组的杀菌效果达到国标( GB19298 -2003)时,所需的时阃及温度均小于电炉加热对照组;实验组和对照组在水温为35.0℃时比初温13.1℃时细菌含量高;实验组和对照组杀菌效果达到国标时,微波炉的效率比电炉高.%Efficiency of sterilizing tap water heated by microwave oven and electric furnace in the same power was compared in the present investigation. The results showed that time and temperature, for sterilization in line with the national standard ( GB19298 - 2003 ) , by microwave method were less and lower than those by the furnace. The bacteria quantity in the water at about 35. Ot by both heating methods was higher than that in the initial temperature (13. It ). Microwave oven was more efficient than the electric stove in sterilization confroming to the GB code.