WorldWideScience

Sample records for bactericides

  1. Bactericidal block copolymer micelles.

    Science.gov (United States)

    Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo

    2011-05-12

    Block copolymer micelles with bactericidal properties were designed to deactivate pathogens such as E. coli bacteria. The micelles of PS-b-PAA and PS-b-P4VP block copolymers were loaded with biocides TCMTB or TCN up to 20 or 30 wt.-%, depending on the type of antibacterial agent. Bacteria were exposed to loaded micelles and bacterial deactivation was evaluated. The micelles loaded with TCN are bactericidal; bacteria are killed in less than two minutes of exposure. The most likely interpretation of the data is that the biocide is transferred to the bacteria by repeated micelle/bacteria contacts, and not via the solution. PMID:21275041

  2. Bactericidal activity of biomimetic diamond nanocone surfaces.

    Science.gov (United States)

    Fisher, Leanne E; Yang, Yang; Yuen, Muk-Fung; Zhang, Wenjun; Nobbs, Angela H; Su, Bo

    2016-03-01

    The formation of biofilms on implant surfaces and the subsequent development of medical device-associated infections are difficult to resolve and can cause considerable morbidity to the patient. Over the past decade, there has been growing recognition that physical cues, such as surface topography, can regulate biological responses and possess bactericidal activity. In this study, diamond nanocone-patterned surfaces, representing biomimetic analogs of the naturally bactericidal cicada fly wing, were fabricated using microwave plasma chemical vapor deposition, followed by bias-assisted reactive ion etching. Two structurally distinct nanocone surfaces were produced, characterized, and the bactericidal ability examined. The sharp diamond nanocone features were found to have bactericidal capabilities with the surface possessing the more varying cone dimension, nonuniform array, and decreased density, showing enhanced bactericidal ability over the more uniform, highly dense nanocone surface. Future research will focus on using the fabrication process to tailor surface nanotopographies on clinically relevant materials that promote both effective killing of a broader range of microorganisms and the desired mammalian cell response. This study serves to introduce a technology that may launch a new and innovative direction in the design of biomaterials with capacity to reduce the risk of medical device-associated infections. PMID:26992656

  3. 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. PMID:22209121

  4. 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.

  5. Acorus calamus Linn.: phytoconstituents and bactericidal property.

    Science.gov (United States)

    Joshi, Rajesh K

    2016-10-01

    Acorus calamus Linn. of the family Araceae (Acoraceae), commonly known as Sweet Flag and Vacha. The rhizome of this plant has medicinal properties against bugs, moths, lice and emetic stomach in dyspepsia. Chemical composition of the hydro-distilled essential oil obtained from the rhizomes of A. calamus was analyzed by gas chromatography equipped with flame ionization detector and gas chromatography coupled with mass spectrometry. The essential oil of A. calamus and its major compound β-asarone were tested against five Gram-positive, eight Gram-negative bacteria, and three fungi by the tube-dilution method at a concentration rang of 5.0-0.009 mg/mL. Forty constituents were identified which comprised 98.3 % of the total oil. The major compound β-asarone (80.6 %) was identified and confirm by NMR ((1)H- & (13)C-) in rhizome oil of A. calamus. The organism Micrococcus luteus was found to be more susceptible to the oil with minimum bactericidal concentration (MBC) value of 0.032 ± 0.004 mg/mL, followed by Aspergillus fumigatus, Aspergillus niger and Micrococcus flavus with MBC values of 0.104 ± 0.016, 0.117 ± 0.017 and 0.143 ± 0.013 mg/mL, respectively. The compound β-asarone was susceptible to the microorganism A. niger with MBC value 0.416 ± 0.065 mg/mL. The present study revealed that tetraploid variety of A. calamus is growing in this region with substantial amount of β-asarone. The oil showed bactericidal property against tested bacteria and fungi. The β-asarone exhibited poorer bactericidal activity against test microorganisms. PMID:27562598

  6. 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.

  7. Tolerance of staphylococci to bactericidal antibiotics.

    Science.gov (United States)

    Vaudaux, Pierre; Lew, Daniel P

    2006-05-01

    Antibiotic therapy for deep-seated staphylococcal infections, especially when they are associated with artificial devices used for orthopedic surgery is often associated with failure. Standard anti-staphylococcal bactericidal antibiotics, such as semi-synthetic penicillins, cephalosporins, or glycopeptides, are effective when given prophylactically in clinical conditions or experimental trials of implant-related infections. However, the efficacy of all anti-staphylococcal agents is seriously diminished on already established implant-related deep-seated infections, which then frequently require surgical implant removal to obtain a cure. The failure of antibiotic therapy to cure established staphylococcal foreign-body infections may arise in part from a broad-spectrum phenotypic tolerance expressed in vivo to different classes of antimicrobial agents. The molecular and physiological mechanisms of this in vivo tolerance remain poorly understood. PMID:16651066

  8. Hierarchical polymer coating for optimizing the antifouling and bactericidal efficacies.

    Science.gov (United States)

    Yan, Shunjie; Song, Lingjie; Li, Zhihong; Luan, Shifang; Shi, Hengchong; Xin, Zhirong; Li, Shenghai; Yang, Yuming; Yin, Jinghua

    2016-10-01

    The bacteria-repellent and bactericidal functionalities in a single system are generally need to be carefully optimized in order to obtain the highest antibacterial performance. In this study, the controlled SI-PIMP strategy was developed for creating hierarchical polymer brushes possessing the bacteria-repellent and bactericidal functionalities. To obtain a bactericidal surface with minimal interference to its nonfouling property, optimization studies were conducted by facilely tailoring the surface density of the quaternary ammonium compound moieties through control over the monomer concentration. An optimal hierarchical polymer coating showed potent protein and bacteria repellence as well as certain bactericidal property. The longlasting antibacterial performance was also achieved due to the good balance between the dual functionalities. The tenability of the hierarchical polymer coating is applicable to surface chemistries for biosensors, molecular imaging, and biomedical applications. PMID:27363527

  9. 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

  10. 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.

  11. 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.

  12. Study of Bactericidal Properties of Propolis

    Directory of Open Access Journals (Sweden)

    Daniela Marina Mot

    2014-05-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE The antibacterial activity of an alcoholic extract of propolis from Apis mellifera was investigated using a method of growth inhibition in the culture medium of microorganisms. For this study were been chosen bacterial species implicated in severe infections in animals: Streptococcus suis, Staphylococcus aureus, Escherichia coli, Salmonella spp., Pseudomonas aeruginosa and Pasteurella haemolytica (Mannheimia haemolytica, 1999. The propolis extract demonstrated to possess bactericidal properties against studied microorganisms in descending order as follows: Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Pasteurella haemolytica, Salmonella spp. All these results demonstrates the possibility of using propolis in either treatment alone, as a natural alternative, be associated with an appropriate antibiotic for the potentiation effect in the event of serious infections in animals. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

  13. 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.

  14. Bacteriostatic and Bactericidal Activities of Moxifloxacin against Coxiella burnetii

    OpenAIRE

    Rolain, Jean-Marc; Maurin, Max; Raoult, Didier

    2001-01-01

    The in vitro activity of moxifloxacin against Coxiella burnetii was compared to those of pefloxacin, ofloxacin, and doxycycline. MICs of moxifloxacin ranged from 0.5 to 1 μg/ml for the Nine Mile, Priscilla, and Q212 strains. Moxifloxacin was not bactericidal against C. burnetii at 4 μg/ml.

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

    NARCIS (Netherlands)

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

    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

  16. 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

  17. 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.

  18. The bactericidal activity of glutaraldehyde-impregnated polyurethane

    OpenAIRE

    Allan, E.; Sehmi, S.; Parkin, I.; MacRobert, A.

    2016-01-01

    Although glutaraldehyde is known to be bactericidal in solution, its potential use to create novel antibacterial polymers suitable for use in healthcare environments has not been evaluated. Here, novel materials were prepared in which glutaraldehyde was either incorporated into polyurethane using a simple “swell-encapsulation-shrink” method (hereafter referred to as “glutaraldehyde-impregnated polyurethane”), or simply applied to the polymer surface (hereafter referred to as “glutaraldehyde-c...

  19. Powerful Bactericidal Activity of Moxifloxacin in Human Leprosy▿

    OpenAIRE

    Pardillo, Fe Eleanor F.; Burgos, Jasmin; Fajardo, Tranquilino T.; Cruz, Eduardo Dela; Abalos, Rodolfo M.; Paredes, Rose Maria D.; Andaya, Cora Evelyn S.; Gelber, Robert H.

    2008-01-01

    In a clinical trial of moxifloxacin in eight multibacillary leprosy patients, moxifloxacin proved highly effective. In all trial patients, a single 400-mg dose of moxifloxacin resulted in significant killing (P ≤ 0.006) of Mycobacterium leprae, ranging from 82% to 99%, with a mean of 91%. In all instances, no viable bacilli were detected with an additional 3 weeks of daily therapy, this observed rapid bactericidal activity being matched previously only by rifampin. On moxifloxacin therapy, sk...

  20. Bactericidal and cytotoxic effects of hypothiocyanite-hydrogen peroxide mixtures.

    OpenAIRE

    Carlsson, J.; Edlund, M B; Hänström, L.

    1984-01-01

    Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide into hypothiocyanite, a reaction which can protect bacterial and mammalian cells from killing by hydrogen peroxide. The present study demonstrates, however, that lactoperoxidase in the presence of thiocyanate can actually potentiate the bactericidal and cytotoxic effects of hydrogen peroxide under specific conditions, such as when hydrogen peroxide is present in the reaction mixtures in excess of thiocyanate. The toxi...

  1. Rapid infrared determination of the potency of chlorinated bactericides.

    Science.gov (United States)

    Spagnolo, F; Cestaro, J P

    1971-06-01

    A rapid infrared reflectance method for evaluating the germicidal potency of synthetic materials containing various amounts of two chlorinated bactericides was developed. The dimeric product 2,2'-methylenebis (4,6-dichlorophenol) exhibited a characteristic C=C skeletal inplane stretching infrared absorption band at 1,640 cm(-1). The monomeric 2,4-dichlorophenol precursor showed a characteristic absorption band at 1,579 cm(-1). These characteristic infrared absorptions may be used for analysis of the potency of the manufactured chlorinated bactericide. For a series of samples known to vary in dimer content, the micrograms per milliliter required for a 100% bacterial kill is first determined by a standard American Petroleum Institute method. Then the area ratio of the infrared absorption bands characteristic of the chlorinated bactericides is measured for each sample and plotted versus the microgram per milliliter required for 100% bacterial kill. The potency of subsequent samples is simply and rapidly determined by measuring this ratio from the infrared absorption curve and calculating micrograms per milliliter required for 100% kill from the calibration curve. Analysis time is approximately 1 hr compared to biocidal tests in current use requiring approximately a 1-month incubation period. PMID:5564677

  2. Blood bactericidal assay (Pasteurella haemolytica) comparison of morbidity in marketed feeder calves.

    Science.gov (United States)

    Purdy, C W; Richards, A B; Foster, G S

    1989-02-01

    An in vitro bactericidal assay that used bovine heparinized blood was investigated for its usefulness in detecting differences in the bactericidal immunity of calves against Pasteurella haemolytica serotype 1 (Ph1). Greater than 90% of killing occurred within 30 minutes. The substitution of fetal calf serum for autologous calf plasma caused loss of bactericidal activity of the blood. Decomplemented calf serum also was low in bactericidal activity. The blood bactericidal assay appears to be opsonin antibody-dependent and complement-dependent. The coefficient of variation (CV) that can be expected with this assay was established by use of a group of 8 calves; within-day CV maximum was 0.9, and between-day CV maximum was 2.1. The blood bactericidal assay was used to evaluate 30 calves under typical market stress from 4 farms in eastern Tennessee. All calves had decreased bactericidal activity, as they moved into a feedyard in Texas. The bactericidal activity was reduced among sick calves, based on the severity of clinical signs. Morbidity was highest during the first 14 days in the feedlot. During this period, healthy calves had a decreased bactericidal index (BI) of 4 points, and calves with clinical signs of bovine respiratory tract disease for 3 days had a decreased BI of 8 points. The average reduction in the BI of calves with clinical signs of bovine respiratory tract disease for 6 or more days was 14 points. PMID:2719384

  3. Bactericidal activity of metal-mediated peroxide-ascorbate systems.

    Science.gov (United States)

    Drath, D B; Karnovsky, M L

    1974-11-01

    Model systems containing ascorbate, hydrogen peroxide, and divalent copper or cobalt have been shown to possess marked bactericidal activity. At equivalent concentrations, copper-containing systems were more bactericidal than the corresponding mixtures containing cobalt. Cobalt at concentrations below 10(-4) M did not appreciably augment microbicidal activity, whereas systems containing copper at concentrations as low as 5 x 10(-6) M were still capable of causing some bacterial death. Manganese was inactive. None of these systems was as potent as the well known myeloperoxidase-peroxide-halide system. The mechanisms of action of these systems are not as yet clear. The possibility that they function through the generation of superoxide (O(2) (-)), hydroxyl radical (OH.), or other free radicals was explored through the use of superoxide dismutase and several free radical scavengers. It seems likely at present that the two active metal-mediated systems function via separate mechanisms. The copper system acts with dehydroascorbate, whereas the cobalt system does not. Activity in the cobalt system appears to depend upon the generation of free radicals. PMID:16558093

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

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    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.

  5. Test industrial pumping of an oil displacement bactericide at the Neftyannyye Kamni deposit

    Energy Technology Data Exchange (ETDEWEB)

    Suleymanov, A.B.; Amirov, G.B.; Kandinskaya, L.I.; Kerimov, K.S.; Mamedov, E.A.; Mamedov, N.G.; Pashayev, N.G.

    1983-01-01

    The results are cited of works conducted to increase the oil production of the stratum at the Neftyannyye Kamni deposit through pumping an oil displacement bactericide (BNV), and the issues for selecting an object and process technology for the successful introduction of flooding with the oil displacement bactericide are discussed.

  6. 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

    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...

  7. Bactericidal synergy of lysostaphin in combination with antimicrobial peptides.

    Science.gov (United States)

    Desbois, A P; Coote, P J

    2011-08-01

    Drug-resistant staphylococci constitute a serious problem that urgently requires the discovery of new therapeutic agents. There has been a resurgence in interest in using lysostaphin (a specific anti-staphylococcal enzyme) as a treatment for infections caused by these important pathogens. However, bacterial resistance to lysostaphin is a problem, but the use of a combination treatment may surmount this issue. In this present study, using viable counts from suspension incubations, lysostaphin is shown to be synergistically bactericidal in combination with various conventional antimicrobial peptides, the antimicrobial protein bovine lactoferrin, a lantibiotic (nisin), and certain lipopeptides used clinically (colistin, daptomycin and polymyxin B). Combinations that act in synergy are of clinical importance as these reduce the doses of the compounds needed for effective treatments and decrease the chances of resistance being selected. The use of lysostaphin in combination with a peptide may represent a new avenue in tackling drug-resistant staphylococci. PMID:21311938

  8. 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...

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Effect of peritoneal dialysis fluid and pH on bactericidal activity of ciprofloxacin.

    OpenAIRE

    McCormick, E M; Echols, R M

    1987-01-01

    Ciprofloxacin is active in vitro against most bacteria that cause peritonitis associated with peritoneal dialysis. We compared the effects of pH (5.5 and 7.4) and medium (dialysis fluid) on the bactericidal activity of ciprofloxacin, tobramycin, vancomycin plus rifampin, and rifampin against Pseudomonas aeruginosa, Escherichia coli, and three strains of staphylococci. The bactericidal activity of ciprofloxacin was not significantly affected by pH or medium, in contrast to the activity of tobr...

  17. Cicada Wing Surface Topography: An Investigation into the Bactericidal Properties of Nanostructural Features.

    Science.gov (United States)

    Kelleher, S M; Habimana, O; Lawler, J; O' Reilly, B; Daniels, S; Casey, E; Cowley, A

    2016-06-22

    Recently, the surface of the wings of the Psaltoda claripennis cicada species has been shown to possess bactericidal properties and it has been suggested that the nanostructure present on the wings was responsible for the bacterial death. We have studied the surface-based nanostructure and bactericidal activity of the wings of three different cicadas (Megapomponia intermedia, Ayuthia spectabile and Cryptotympana aguila) in order to correlate the relationship between the observed surface topographical features and their bactericidal properties. Atomic force microscopy and scanning electron microscopy performed in this study revealed that the tested wing species contained a highly uniform, nanopillar structure on the surface. The bactericidal properties of the cicada wings were investigated by assessing the viability of autofluorescent Pseudomonas fluorescens cells following static adhesion assays and targeted dead/live fluorescence staining through direct microscopic counting methods. These experiments revealed a 20-25% bacterial surface coverage on all tested wing species; however, significant bactericidal properties were observed in the M. intermedia and C. aguila species as revealed by the high dead:live cell ratio on their surfaces. The combined results suggest a strong correlation between the bactericidal properties of the wings and the scale of the nanotopography present on the different wing surfaces. PMID:26551558

  18. Insights into the Mechanism of Action of Bactericidal Lipophosphonoxins.

    Directory of Open Access Journals (Sweden)

    Natalya Panova

    Full Text Available The advantages offered by established antibiotics in the treatment of infectious diseases are endangered due to the increase in the number of antibiotic-resistant bacterial strains. This leads to a need for new antibacterial compounds. Recently, we discovered a series of compounds termed lipophosphonoxins (LPPOs that exhibit selective cytotoxicity towards Gram-positive bacteria that include pathogens and resistant strains. For further development of these compounds, it was necessary to identify the mechanism of their action and characterize their interaction with eukaryotic cells/organisms in more detail. Here, we show that at their bactericidal concentrations LPPOs localize to the plasmatic membrane in bacteria but not in eukaryotes. In an in vitro system we demonstrate that LPPOs create pores in the membrane. This provides an explanation of their action in vivo where they cause serious damage of the cellular membrane, efflux of the cytosol, and cell disintegration. Further, we show that (i LPPOs are not genotoxic as determined by the Ames test, (ii do not cross a monolayer of Caco-2 cells, suggesting they are unable of transepithelial transport, (iii are well tolerated by living mice when administered orally but not peritoneally, and (iv are stable at low pH, indicating they could survive the acidic environment in the stomach. Finally, using one of the most potent LPPOs, we attempted and failed to select resistant strains against this compound while we were able to readily select resistant strains against a known antibiotic, rifampicin. In summary, LPPOs represent a new class of compounds with a potential for development as antibacterial agents for topical applications and perhaps also for treatment of gastrointestinal infections.

  19. Bactericidal action of positive and negative ions in air

    Directory of Open Access Journals (Sweden)

    Sleigh P Andrew

    2007-04-01

    . However in the case of Mycobacterium parafortuitum, electroporation resulting from exposure to the electric field appears to have been the principal cause of cell inactivation. Conclusion The results of the study suggest that the bactericidal action attributed to negative air ions by previous researchers may have been overestimated.

  20. 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.

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

    International Nuclear Information System (INIS)

    In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO2 (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO2 is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO2. 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-TiO2 and chitosan/TiO2 (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/TiO2 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.

  2. [Comparative urinary bactericidal activity of oral antibiotics against gram-positive pathogens].

    Science.gov (United States)

    Bedenić, Branka; Budimir, Ana; Gverić, Ana; Plecko, Vanda; Vranes, Jasmina; Bubonja-Sonje, Marina; Kalenić, Smilja

    2012-01-01

    In routine bacteriological laboratories the antibacterial activity of antibiotics is determined by in vitro testing, usually by disk-diffusion test. However, in vitro testing does not always reflect antibacterial efficiency of antibiotics in vivo. In this investigation, the urine samples obtained in a single oral dose pharmacokinetic study were examined for their bactericidal activity against a range of relevant Gram-positive urinary tract pathogens. Urinary bactericidal activity of linezolid had been previously compared with ciprofloxacin but not with other oral antibiotics such as beta-lactams. Linezolid showed satisfactory urinary bactericidal titres throughout the whole testing period against all Gram-positive cocci. Fluoroquinolones displayed high and persisting levels of urinary bactericidal activity against staphylococci, but their activity against enterococci was weaker. According to the results of ex-vivo testing amoxycillin could be recommended only for infections caused by E. faecalis. Amoxycillin combined with clavulanic acid can be considered as a therapeutic option for infections caused by S. saprophyticus and E. faecalis. Older cephalosporins had high titres only against S. saprophyticus. Their drawback is a short elimination half-time in urine resulting in rapid decrease of urinary bactericidal titers during dosing interval. Furthermore, they do not show activity against enterococci due to their intrinsic resistance to cephalosporins. PMID:22930932

  3. 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.

  4. Effects of cytochalasin B on the intrcellular bactericidal activity of human neutrophils.

    Science.gov (United States)

    Okuda, K

    1975-06-01

    Cytochalasin B (CB) is known to have some inhibitory effects on cytokinesis, single-cell movement, bacterial uptake by phagocytes, and many other processes. The effects of CB on intraleukocytic bactericidal activities in human leukocytes were studied, and the results were summarized as follows. (i) CB inhibited the early stage of the intracellular bactericidal activity of human leukocytes against Streptococcus pyogenes D58 (group A). The effect was rapidly eliminated by rinsing the CB solution. (ii) In the late stage of the intracellular bactericidal process, however, CB possessed no effect against S. pyogenes D58 (group A) and Staphylococcus aureus 209P. (iii) CB also inhibited the translocation of myeloperoxidase granules to the phagosomes of human neutrophils. PMID:1155917

  5. 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.

  6. 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. PMID:24662462

  7. 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.

  8. Whole-blood phagocytic and bactericidal activities of atomic bomb survivors, Hiroshima and Nagasaki

    International Nuclear Information System (INIS)

    This in vitro study evaluated the phagocytic and bactericidal activities of leukocytes in aliquots of whole blood from Hiroshima and Nagasaki atomic bomb survivors for Staphylococcus aureus. The data were analyzed by multiple linear regression. Any significant effects of exposure to A-bomb radiation could not be detected for both phagocytic and bactericidal activities of whole blood from A-bomb survivors. In addition, there were no significant effects of age categories, sex or city, except in neutrophil counts. (J.P.N.)

  9. 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

  10. 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

  11. The bactericidal activity of a teat dip containing chlorhexidine and cetrimide.

    Science.gov (United States)

    King, J S; Morant, S V; Bramley, A J

    1977-11-19

    Using an in vivo test on teat skin the disinfectant activity of a teat dip containing chlorhexidine and cetrimide was compared with two iodophor solutions, one containing the recommended concentration of 0.5 per cent available iodine and the other a 10-fold dilution of this (0.05 per cent iodine). The test organisms used were Staphylococcus aureus and Escherichia coli and for both species the 0.5 per cent iodophor was significantly more bactericidal than either the diluted iodophor or the chlorhexidine/cetrimide teat dip (P less than 0.01). In the test against S aureus, chlorhexidine/cetrimide and the 0.05 per cent iodophor showed similar bactericidal activity, but the iodophor was significantly more bactericidal against E coli (P less than 0.01). It is argued that due to its low bactericidal activity this formulation of chlorhexidine/cetrimide is likely to be inferior to 0.5 per cent iodophor solution as a disinfectant teat dip. PMID:339477

  12. 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.

  13. 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

  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. 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

  16. 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...

  17. 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. PMID:27350429

  18. 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.

  19. Bactericidal Activity of Quinupristin-Dalfopristin against Staphylococcus aureus: Clindamycin Susceptibility as a Surrogate Indicator

    OpenAIRE

    Fuchs, Peter C.; Barry, Arthur L.; Brown, Steven D.

    2000-01-01

    Of 516 Staphylococcus aureus strains tested, 97.1% were susceptible to quinupristin-dalfopristin, which was bactericidal for 22 (56%) of the 39 strains tested, comparable to vancomycin. All 17 clindamycin and macrolide-resistant strains were inhibited but not killed by quinupristin-dalfopristin, whereas all 22 clindamycin-susceptible strains (5 were macrolide resistant) were killed.

  20. [Bacteriostatic effect and/or xylitol bactericide of crops on Listeria Monocytogenes].

    Science.gov (United States)

    Morón de Salim, Alba Rosa; Ramírez Mérida, Luis Guillermo

    2013-06-01

    Listeria monocytogenes has been considered as an emerging pathogen causing foodborne illness. In the search for an alternate route biocontrol propagation, xylitol has been proposed as a possible bacteriostatic and / or bactericide. Xylitol is a polyol derived from the hydrogenation of xylose monosaccharide of importance in the pharmaceutical industry for its anti-cariogenic effect. To check the possible effect of xylitol as bacteriostatic and/or bactericidal against Listeria monocytogenes, it was determined the minimum inhibitory concentration (MIC), the time minimum inhibition (TMI) and minimum bactericidal concentration (MBC) of xylitol solutions on Listeria monocytogenes ATCC 7635. The agar diffusion method was applied, using xylitol solutions at concentrations of 0-10%, respectively, for the MIC. The TMI was determined by growth curves in trypticase soy broth with solutions 1, 2, 3, 5, 8, 9, 10 and 20% of xylitol, respectively, with an initial inoculum of 108 CFU per ml of Listeria monocytogenes in each solution. MIC observed was the solution 1% of xylitol; the TMI was 10 hours to concentrations of 1 to 10% and 7 hours to apply 20% xylitol. It was found that xylitol has bacteriostatic power on Listeria monocytogenes (p < 0.001), but not bactericide effect. PMID:24934074

  1. Hierarchical Polymer Brushes with Dominant Antibacterial Mechanisms Switching from Bactericidal to Bacteria Repellent.

    Science.gov (United States)

    Yan, Shunjie; Luan, Shifang; Shi, Hengchong; Xu, Xiaodong; Zhang, Jidong; Yuan, Shuaishuai; Yang, Yuming; Yin, Jinghua

    2016-05-01

    Although polycationic surfaces have high antimicrobial efficacies, they suffer from high toxicity to mammalian cells and severe surface accumulation of dead bacteria. For the first time, we propose a surface-initiated photoiniferter-mediated polymerization (SI-PIMP) strategy of constructing a "cleaning" zwitterionic outer layer on a polycationic bactericidal background layer to physically hinder the availability of polycationic moieties for mammalian cells in aqueous service. In dry conditions, the polycationic layer exerts the contact-active bactericidal property toward the adherent bacteria, as the zwitterionic layer collapses. In aqueous environment, the zwitterionic layer forms a hydration layer to significantly inhibit the attachment of planktonic bacteria and the accumulation of dead bacteria, while the polycationic layer kills bacteria occasionally deposited on the surface, thus preserving the antibacterial capability for a long period. More importantly, the zwitterionic hydrated layer protects the mammalian cells from toxicity induced by the bactericidal background layer, and therefore hierarchical antibacterial surfaces present much better biocompatibility than that of the naked cationic references. The dominant antibacterial mechanism of the hierarchical surfaces can switch from the bactericidal efficacy in dry storage to the bacteria repellent capability in aqueous service, showing great advantages in the infection-resistant applications. PMID:27049327

  2. LED array designing and its bactericidal effect researching on Pseudomonas aeruginosa in vitro

    Science.gov (United States)

    Fang, Jing; Xing, Jin; Gao, Liucun; Shen, Benjian; Kang, Hongxiang; Jie, Liang; Peng, Chen

    2015-10-01

    Lights with some special waveband and output power density have a bactericidal effect to some special bacteria. In this paper, the bactericidal effect of light at wavelength of 470 nm on P. aeruginosa (ATCC 27853) is researched with different irradiation dose. The light source is a LED array which is obtained by incoherent combine of 36 LEDs with emitting wavelength of 470 nm. The P. aeruginosa suspension is exposed with the LED array at the light power density of 100 mW/cm2 with exposures time of 0, 5, 10, 20, 40, and 80 min, respectively. The numbers of CFU are then determined by serial dilutions on LB agar plates. The bactericidal effect research results of 470 nm LED on P. aeruginosa show that the killing ratio increases with increasing of the exposure time. For the 80 min irradiation, as much as 92.4% reduction of P. aeruginosa is achieved. The results indicate that, in vitro, 470-nm lights produce dose dependent bactericidal effects on P. aeruginosa.

  3. 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

  4. Nanoparticle synthesis of zinc peroxide: structural and morphological characterization for bactericidal applications

    International Nuclear Information System (INIS)

    Zinc peroxide (ZnO2) nanoparticles were synthesized by sol-gel technique. The chemicals used for the synthesis were zinc acetate di-hydrate (Zn(CH3COO)2.2H2O) and hydrogen peroxide (H2O2) at 30 % in an aqueous solution with sonication. The structure of the ZnO2 nanoparticles was characterized by X-ray diffraction. While the morphology and the cluster size were determined using scanning and transmission electron microscopy. For a preliminary evaluation of the bactericidal properties of the ZnO2, the material was exposed to Staphylococcus aureus, Escherichia coli y Bacillus subtili, and the nanoparticles presented good bactericidal properties. (author)

  5. Bactericidal Effect of Aqueous Extracts of the Bark of the Pomegranate (Punica granatum L.) on Bacteria

    OpenAIRE

    Rabah Chadli; Aman Bouzid; Khadidja Bouzid; Hamida Nader

    2015-01-01

    This research concerns the study of antibacterial properties of different aqueous extracts of the bark of the pomegranate (Punica granatum L.). Three bacterial strains were used in this test: Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella. Very interesting bactericidal properties of aqueous extracts of the bark of the pomegranate were found on bacteria. The inhibition zones have a very large diameter up to 20 mm and the MIC and MBC are low, of the order of 0.78 mg/ml. This work ...

  6. 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.

  7. Differential complement activation and susceptibility to human serum bactericidal action by Vibrio species.

    OpenAIRE

    1983-01-01

    The ability of Vibrio vulnificus to resist human serum bactericidal action and to activate human complement was compared with similar cultures of Vibrio cholerae and Vibrio parahaemolyticus. Both V. vulnificus and V. parahaemolyticus had similar survival rates in sera and were much more resistant to killing than was V. cholerae. In contrast, V. vulnificus activated significantly less serum complement than did V. cholerae and V. parahaemolyticus. The relative ability of V. vulnificus to surviv...

  8. Bactericidal effect of 5-azacytidine on Escherichia coli carrying EcoRII restriction-modification enzymes.

    OpenAIRE

    Friedman, S.

    1982-01-01

    5-Azacytidine was found to be bactericidal to Escherichia coli carrying plasmids specifying EcoRII restriction-modification systems, but not to the same strains lacking these plasmids. Of other base analogs tested, only 5(beta-D-ribofuranosyl)isocytidine had similar, although weaker, effects. Plasmids that had lost the EcoRII restriction-modification system did not confer sensitivity to 5-azacytidine. Mutants defective in the restriction function remained sensitive to the toxic effects of the...

  9. Verapamil Increases the Bactericidal Activity of Bedaquiline against Mycobacterium tuberculosis in a Mouse Model

    OpenAIRE

    Gupta, Shashank; Tyagi, Sandeep; Bishai, William R.

    2014-01-01

    Bedaquiline is a newly approved drug for the treatment of multidrug-resistant tuberculosis, but there are concerns about its safety in humans. We found that the coadministration of verapamil with subinhibitory doses of bedaquiline gave the same bactericidal effect in mice as did the full human bioequivalent bedaquiline dosing. Adding verapamil to bedaquiline monotherapy also protected against the development of resistant mutants in vivo. The adjunctive use of verapamil may permit use of lower...

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

    OpenAIRE

    Koul, Anil; Vranckx, Luc; Dhar, Neeraj; Gohlmann, Hinrich W. H.; Özdemir, Muhittin Emre; Neefs, Jean-Marc; Schulz, Melanie; Lu, Ping; Mortz, Ejvind; McKinney, John D.; Andries, Koen; Bald, Dirk

    2014-01-01

    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 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 inhib...

  11. 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.

  12. Investigation of the bactericidal effects of vancomycin and quinupristin/dalfopristin on Staphylococcus aureus isolates

    OpenAIRE

    HOŞGÖR-LİMONCU, Mine; ERMERTCAN, Şafak; COŞAR, Güner

    2004-01-01

    The present study aimed to determine the correlation between the bactericidal activity of vancomycin and quinupristin/dalfopristin (Q/D) on Staphylococcus aureus isolates and their minimal inhibition concentrations. The in-vitro susceptibilities of the 99 S. aureus isolates to vancomycin and Q/D were investigated by agar dilution. Thirty methicillin-resistant S. aureus (MRSA) and 30 methicillin-susceptible S. aureus (MSSA) vancomycin and Q/D susceptible isolates were involved in time-kill stu...

  13. Early Bactericidal Activity of Moxifloxacin in Treatment of Pulmonary Tuberculosis: a Prospective, Randomized Study

    OpenAIRE

    Pletz, Mathias W. R.; De Roux, Andres; Roth, Andreas; NEUMANN, Karl-Heinz; Mauch, Harald; Lode, Hartmut

    2004-01-01

    Moxifloxacin is the most active fluoroquinolone against Mycobacterium tuberculosis in vitro. However, data about the efficacy in patients are not available. We enrolled 17 patients with tuberculosis in a prospective, randomized study. After 5 days of monotherapy with either moxifloxacin or isoniazid, we detected significant decreases in mean CFU per milliliter in sputum in both groups. The calculated early bactericidal activities for isoniazid and moxifloxacin were 0.209 and 0.273 log10 CFU p...

  14. 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.

  15. Bactericidal Activity of Some Lichen Secondary Compounds of Cladonia ochrochlora , Parmotrema nilgherrensis & Parmotrema sancti-angelii

    Directory of Open Access Journals (Sweden)

    VERMA NEERAJ

    2011-06-01

    Full Text Available In the present study, bactericidal potential of some lichen secondary compounds has been presented. Three lichen species namely Cladonia ochrochlora, Parmotrema nilgherrensis and Parmotrema sancti-angelii were successively fractionated in various organic solvents nhexane, ethyl acetate, acetone and methanol. The ethyl acetate fraction (10 μg/ml of these lichen species showed promised bactericidal activity and the order of the activity of lichen species were found as P. nilgherrensis > P. sanctiangelii > C. ochrochlora. Seven lichen secondary compounds alectoronic acid, atranorin, $-collatolic acid, fumarprotocetraric acid, hypoprotocetraric acid, lecanoric acid and protocetraric acid isolated from ethyl acetate fraction of above lichen species demonstrated moderate to strong bactericidal activity with low MIC value; alectoronic acid showed MIC 21.9 μg to 162.1 μg/ml, atranorin (5 μg - 70.7 μg/ml, $-collatolic acid (8.6 μg - 245 μg/ml, fumarprotocetraric acid (24 μg - 227.3 μg/ml, hypoprotocetraric acid (12.2 μg - 278.5 μg/ml, lecanoric acid (24.6 μg - 591.7 μg/ml, protocetraric acid (18.7 μg - 740.7 μg/ml. These secondary compounds were found most effective to kill microorganisms within a period of 0 hrs to 6 hrs incubation as evident from the kinetic time kill assay study. As far as the stability of the lichen compounds for the observed activity, it was found that these compounds were stable at 4oC without loosing their bactericidal potential.

  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. 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

  18. [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.

  19. 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.

  20. [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. PMID:23477211

  1. Bactericidal activity of Musca domestica cecropin (Mdc) on multidrug-resistant clinical isolate of Escherichia coli.

    Science.gov (United States)

    Lu, X; Shen, J; Jin, X; Ma, Y; Huang, Y; Mei, H; Chu, F; Zhu, J

    2012-08-01

    The housefly (Musca domestica) larvae have been used clinically to cure osteomyelitis, decubital necrosis, lip boil, ecthyma and malnutritional stagnation ever since the Ming/Qing Dynasty (1368 Anno Domini) till now, in China. In prior research, we have cloned and characterized a new gene of antimicrobial peptide cecropin from M. domestica larvae. This peptide was potently active against Gram-positive and Gram-negative bacteria standard strain. In the present study, we evaluated the possibility of Mdc to be a potential bactericidal agent against clinical isolates of multidrug-resistant (MDR) Escherichia coli and to elucidate the related antimicrobial mechanisms. Antimicrobial activity assays indicated a minimal inhibitory concentration (MIC) of 1.56 μM. Bactericidal kinetics at MIC showed that Mdc rapid killing of MDR E. coli. Lipopolysaccharide (LPS) dose-dependently suppressed Mdc antibacterial potency indicates that LPS is the initial binding site of Mdc in E. coli. Propidium iodide-based flow cytometry revealed that Mdc causes E. coli membrane permeabilization. Transmission electron micrographs further indicated that a remarkable damage in the bacteria's outer and inner membrane, even the leakage of cytoplasmic contents induced by Mdc. DNA binding experimental result implies that DNA is one of the possible intracellular targets of Mdc. Of note, Mdc did not show a perceptible cytotoxic effect on human red blood cells. Altogether, these results suggest that Mdc could be an excellent candidate for the development of more efficacious bactericidal agents. PMID:22202966

  2. Analysis by confocal laser scanning microscopy of the MDPB bactericidal effect on S. mutans biofilm CLSM analysis of MDPB bactericidal effect on biofilm

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    Fabíola Galbiatti de Carvalho

    2012-10-01

    Full Text Available Since bacteria remain in the dentin following caries removal, restorative materials with antibacterial properties are desirable to help maintaining the residual microorganisms inactive. The adhesive system Clearfil Protect Bond (PB contains the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB in its primer, which has shown antimicrobial activity. However, its bactericidal effect against biofilm on the dentin has been little investigated. Objective: The aim of this study was to analyze by confocal laser scanning microscopy (CLSM and viable bacteria counting (CFU the MDPB bactericidal effect against S. mutans biofilm on the dentin surface. Material and methods: Bovine dentin surfaces were obtained and subjected to S. mutans biofilm formation in BHI broth supplemented with 1% (w/v sucrose for 18 h. Samples were divided into three groups, according to the primer application (n=3: Clearfil Protect Bond (PB, Clearfil SE Bond, which does not contain MDPB, (SE and saline (control group. After the biofilm formation, Live/ Dead stain was applied directly to the surface of each sample. Next, 10 µL of each primer were applied on the samples during 590 s for the real-time CLSM analysis. The experiment was conducted in triplicate. The primers and saline were also applied on the other dentin samples during 20, 90, 300 and 590 s (n=9 for each group and period evaluated and the CFU were assessed by colonies counting. Results: The results of the CLSM showed that with the Se application, although non-viable bacteria were detected at 20 s, there was no increase in their count during 590 s. In contrast, after the PB application there was a gradual increase of non-viable bacteria over 590 s. Conclusions: The quantitative analysis demonstrated a significant decrease of S. mutans CFU at 90 s PB exposure and only after 300 s of Se application. Protect Bond showed an earlier antibacterial effect than Se Bond.

  3. Association of Bactericidal Dysfunction of Paneth Cells in Streptozocin-Induced Diabetic Mice with Insulin Deficiency.

    Science.gov (United States)

    Yu, Tao; Yang, Hong-Sheng; Lu, Xi-Ji; Xia, Zhong-Sheng; Ouyang, Hui; Shan, Ti-Dong; Huang, Can-Ze; Chen, Qi-Kui

    2016-01-01

    BACKGROUND Type 1 diabetes mellitus (T1DM) is associated with increased risks of enteric infection. Paneth cells constitute the first line of the gut defense. Little is known about the impact of T1DM on the bactericidal function of intestinal Paneth cells. MATERIAL AND METHODS A T1DM mouse model was induced by intraperitoneal injection of streptozocin. The analysis of intestinal microbiota and the mucosal bactericidal assay were conducted to evaluate intestinal innate defense. Numbers of Paneth cells and their expression of related antimicrobial peptides were analyzed. Expression of total insulin receptor (IR) mRNA and relative levels of IR-A/IR-B were analyzed. The primary mouse small intestinal crypt culture was used to analyze the effect of insulin and glucose on the expression of related antimicrobial peptides of Paneth cells. RESULTS In T1DM mice, bacterial loads were increased and there was an alteration in the composition of the intestinal microflora. Exogenous bacteria had better survival in the small bowel of the T1DM mice. The expression of Paneth cell-derived antimicrobial peptides was significantly decreased in the T1DM mice, although the number of Paneth cells was increased. Relative levels of IR-A/IR-B in Paneth cells of diabetic mice were elevated, but the total IR mRNA did not change. Insulin treatment restored the expression of antimicrobial peptides and normalized the microbiota in the gut of T1DM mice. Subsequently, in vitro culture assay demonstrated that insulin rather than glucose was essential for the optimal expression of Paneth cell-derived antimicrobial peptides. CONCLUSIONS The bactericidal function of intestinal Paneth cells was impaired in STZ-induced diabetic mice, resulting in the altered intestinal flora, and insulin was essential for the optimal expression of Paneth cell-derived antimicrobial peptides. PMID:27572949

  4. 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.

  5. 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.

  6. 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

    2016-01-01

    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. PMID:27346695

  7. Systemic hypoxia enhances exercise-mediated bactericidal and subsequent apoptotic responses in human neutrophils.

    Science.gov (United States)

    Wang, Jong-Shyan; Chiu, Ya-Ting

    2009-10-01

    Phagocytosis and oxidative burst are critical host defense mechanisms in which neutrophils clear invading pathogens. Clearing phagocytic neutrophils by triggering apoptosis is an essential process for controlling inflammation. This study elucidates how various exercise bouts with/without hypoxia affected neutrophil bactericidal activity and subsequent apoptosis in humans. Fifteen sedentary males performed six distinct experimental tests in an air-conditioned normobaric hypoxia chamber: two normoxic exercises [strenuous exercise (SE; up to maximal O2 consumption) and moderate exercise (ME; 50% maximal O2 consumption for 30 min) while exposed to 21% O2], two hypoxic exercises (ME for 30 min while exposed to 12% and 15% O2), and two hypoxic exposures (resting for 30 min while exposed to 12% and 15% O2). The results showed that 1) plasma complement-C3a desArg/C4a desArg/C5a concentrations were increased, 2) expressions of L-selectin/lymphocyte functin-associated antigen-1/Mac-1/C5aR on neutrophils were enhanced, 3) phagocytosis of neutrophils to Esherichia coli and release of neutrophil oxidant products by E. coli were elevated, and 4) E. coli-induced phosphotidylserine exposure or caspase-3 activation of neutrophils were promoted immediately and 2 h after both 12% O2 exposure at rest and with ME as well as normoxic SE. Although neither normoxic ME nor breathing 15% O2 at rest influenced these complement- and neutrophil-related immune responses, ME at both 12% and 15% O2 resulted in enhanced complement activation in the blood, expressions of opsonic/complement receptors on neutrophils, or the bactericidal activity and apoptosis of neutrophils. Moreover, the increased neutrophil oxidant production and apoptosis by normoxic SE and hypoxic ME were ameliorated by treating neutrophils with diphenylene iodonium (a NADPH oxidase inhibitor). Therefore, we conclude that ME at 12-15% O2 enhances bactericidal capacity and facilitates the subsequent apoptosis of neutrophils. PMID

  8. Viperatoxin-II: A novel viper venom protein as an effective bactericidal agent.

    Science.gov (United States)

    Samy, Ramar Perumal; Stiles, Bradley G; Chinnathambi, Arunachalam; Zayed, M E; Alharbi, Sulaiman Ali; Franco, Octavio Luiz; Rowan, Edward G; Kumar, Alan Prem; Lim, Lina H K; Sethi, Gautam

    2015-01-01

    Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have become a rising threat to public health. There is an urgent need for development of promising new therapeutic agents against drug resistant bacteria like S. aureus. This report discusses purification and characterization of proteins from Indian Russell's viper snake venom. Novel 15-kDa proteins called "Viperatoxin" (VipTx-I and VipTx-II) were extracted from the whole venom and evaluated using in vitro antimicrobial experiments. The N-terminal amino acid sequence of "Viperatoxin" showed high sequence homology to daboiatoxin isolated from the same venom and also matched phospholipase A2 (PLA2) enzymes isolated from other snake venoms. In an in vitro plate assay, VipTx-II but not VipTx-I showed strong antimicrobial effects against S. aureus and Burkholderia pseudomallei (KHW & TES), Proteus vulgaris and P. mirabilis. The VipTx-II was further tested by a broth-dilution assay at 100-3.1 μg/ml concentrations. The most potent bactericidal effect was found at the lowest dilutions (MICs of 6.25 μg/ml) against B. pseudomallei, S. aureus and P. vulgaris (MICs of 12.25 μg/ml). Electron microscopic investigation revealed that the protein-induced bactericidal potency was closely associated with pore formation and membrane damage, even at the lowest concentrations (level of cytotoxic effects as observed in human (THP-1) cells at higher concentrations. Molecular weight determinations of VipTx-II by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed one major, along with a few minor bands. The results indicate that VipTx-II plays a significant role in bactericidal and membrane damaging effects in vitro. Non-cytotoxic properties on human cells highlight it as a promising candidate for further evaluation of antimicrobial potential in vivo. PMID:26793432

  9. 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.

  10. 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.

  11. [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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Antibacterial properties and mechanism of graphene oxide-silver nanocomposites as bactericidal agents for water disinfection.

    Science.gov (United States)

    Song, Biao; Zhang, Chang; Zeng, Guangming; Gong, Jilai; Chang, Yingna; Jiang, Yan

    2016-08-15

    Providing clean and affordable drinking water without harmful disinfection byproducts generated by conventional chemical disinfectants gives rise to the need for technological innovation. Nanotechnology has great potential in purifying water and wastewater treatment. A graphene oxide-silver (GO-Ag) nanocomposite with excellent antibacterial activity was prepared and characterized by transmission electron microscope and X-ray photoelectron spectroscopy. The tests were carried out using Escherichia coli and Staphylococcus aureus as model strains of Gram-negative and Gram-positive bacteria, respectively. The effect of bactericide dosage and pH on antibacterial activity of GO-Ag was examined. Morphological observation of bacterial cells by scanning electron microscope showed that GO-Ag was much more destructive to cell membrane of Escherichia coli than that of Staphylococcus aureus. Experiments were carried out using catalase, superoxide dismutase and sodium thioglycollate to investigate the formation of reactive oxygen species and free silver ions in the bactericidal process. The activity of intracellular antioxidant enzymes was measured to investigate the potential role of oxidative stress. According to the consequence, synergetic mechanism including destruction of cell membranes and oxidative stress accounted for the antibacterial activity of GO-Ag nanocomposites. All the results suggested that GO-Ag nanocomposites displayed a good potential for application in water disinfection. PMID:27170600

  18. 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.

  19. Potential role of autophagy in the bactericidal activity of human PMNs for Bacillus anthracis.

    Science.gov (United States)

    Ramachandran, Girish; Gade, Padmaja; Tsai, Pei; Lu, Wuyuan; Kalvakolanu, Dhananjaya V; Rosen, Gerald M; Cross, Alan S

    2015-12-01

    Bacillus anthracis, the causative agent of anthrax, is acquired by mammalian hosts from the environment, as quiescent endospores. These endospores must germinate inside host cells, forming vegetative bacilli, before they can express the virulence factors that enable them to evade host defenses and disseminate throughout the body. While the role of macrophages and dendritic cells in this initial interaction has been established, the role of polymorphonuclear leukocytes (PMNs) has not been adequately defined. We discovered that while B. anthracis 34F2 Sterne endospores germinate poorly within non-activated human PMNs, these phagocytes exhibit rapid microbicidal activity toward the outgrown vegetative bacilli, independent of superoxide and nitric oxide. These findings suggest that a non-free radical pathway kills B. anthracis bacilli. We also find in PMNs an autophagic mechanism of bacterial killing based on the rapid induction of LC-3 conversion, beclin-1 expression, sequestosome 1 (SQSTM1) degradation and inhibition of bactericidal activity by the inhibitor, 3-methyladenine. These findings extend to PMNs an autophagic bactericidal mechanism previously described for other phagocytes. PMID:26424808

  20. 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.

  1. 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.

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

    International Nuclear Information System (INIS)

    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. - 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

  3. 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.

  4. Environmental monitoring and bactericidal efficacy of chlorine dioxide gas in a dental office.

    Science.gov (United States)

    Kuroyama, Iwao; Osato, Shigeo; Nakajima, Shigeki; Kubota, Ryoichi; Ogawa, Takahiro

    2010-09-01

    We monitored the quantity of airborne microorganisms at 11 points (points A to K) in a dental office on a routine day of use, and tested the bactericidal efficacy of chlorine dioxide (ClO₂) gas in the dental operatory after consulting hours. Fallen airborne microorganisms were collected under air-conditioning (AC) in the dental office, and under four conditions in the operatory. Specimens of the microbes were cultivated on nutrient and Sabouraud agar media (NAM and SAM). Many colonies were observed at the entrance hall and on the cabinet in a disinfection room in the NAM and SAM tests, respectively, while no colony was observed at the foot position of the operating table and treatment bed, and above the head position of the operating room in the NAM and SAM tests, respectively. In the bactericidal efficacy test using ClO₂ gas, the dental operatory could be kept clean by the use of 4 mg/L-ClO₂ gas in addition to the use of an AC with a plasma filter and the HEPA filter. PMID:20938095

  5. The effect of trypsin and chymotrypsin on the bactericidal activity and specific antibody activity of bovine colostrum.

    Science.gov (United States)

    Brock, J H; Arzabe, R; Piñeiro, A; Olivito, A M

    1977-01-01

    Digestion of bovine colostral whey with trypsin or chymotrypsin caused a progressive loss of the complement-mediated bactericidal activity of naturally-occurring colostral antibodies of E. coli 0111. Bactericidal activity was associated primarily with IgG1 immunoglobulin and to a lesser extent with IgM. Chymotrypsin preferentially attacked IgM, destroying its antibacterial activity and producing an apparent decrease in its mol wt. Trypsin preferentially attacked IgG1, but loss of antibacterial activity was in this case not accompanied by a decrease in molecular weight. Using colostral whey with antiperoxidase activity it was shown that the kinetics of loss of specific antibody activity were similar to those of loss of bactericidal activity. It is therefore suggested that trypsin may cause a loss of specific antibody activity of colostral IgG1 without cleaving the immunoglobulin molecule. PMID:321342

  6. 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...... require bacterial metabolic activity, we tested whether the bactericidal effect of colistin depends on the formation of OH·. In Pseudomonas aeruginosa cultures, OH-mediated killing by ciprofloxacin was demonstrated by decreased bacterial survival and induction of 3'-(p-hydroxyphenyl) fluorescein (HPF......· was seen in P. aeruginosa during killing by colistin, and prevention of OH· accumulation could not rescue P. aeruginosa from killing by colistin. These results therefore demonstrate that the bactericidal activity of colistin on P. aeruginosa is not dependent on oxidative stress. In conclusion...

  7. Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films

    Science.gov (United States)

    He, Ziming; Xu, Qingchi; Yang Tan, Timothy Thatt

    2011-12-01

    TiO2-InVO4 nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO2-InVO4 nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO4 and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO2 film, the current TiO2-InVO4 films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell ``photo-fixation'' was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.TiO2-InVO4 nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO2-InVO4 nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO4 and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO2 film, the current TiO2-InVO4 films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell ``photo-fixation'' was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film. Electronic supplementary information (ESI) available: Photocatalytic activity test procedure and results, AFM images, EDX results, LSCM images, and wettability results. See DOI: 10.1039/c1nr11126d

  8. Mechanisms of Bactericidal Action of Cinnamaldehyde against Listeria monocytogenes and of Eugenol against L. monocytogenes and Lactobacillus sakei

    OpenAIRE

    Gill, Alexander O.; Holley, Richard A.

    2004-01-01

    The spice oil components eugenol and cinnamaldehyde possess activity against both gram-positive and gram-negative bacteria, but the mechanisms of action remain obscure. In broth media at 20°C, 5 mM eugenol or 30 mM cinnamaldehyde was bactericidal (>1-log reduction in the number of CFU per milliliter in 1 h) to Listeria monocytogenes. At a concentration of 6 mM eugenol was bactericidal to Lactobacillus sakei, but treatment with 0.5 M cinnamaldehyde had no significant effect. To investigate the...

  9. Postantibiotic effect assessments for antibiotics exhibiting a wide range of bactericidal activities by using a modified total-cell-counting method.

    OpenAIRE

    Li, R. C.; S.W. Lee

    1997-01-01

    We recently described a total-cell-counting method for postantibiotic effect (PAE) assessments that performs well with weakly bactericidal antibiotics. This note presents a modified method for the study of PAE with extended capability to cover a broad range of bactericidal activities.

  10. 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.

  11. 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.

  12. 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.

  13. 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

    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 mi......-fermentable energy sources such as lipids (impeding ATP synthesis via glycolysis). Our results show that BDQ exposure triggers a metabolic remodelling in mycobacteria, thereby enabling transient bacterial survival....... 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...

  14. Bactericidal and virucidal mechanisms in the alkaline disinfection of compost using calcium lime and ash.

    Science.gov (United States)

    Hijikata, Nowaki; Tezuka, Rui; Kazama, Shinobu; Otaki, Masahiro; Ushijima, Ken; Ito, Ryusei; Okabe, Satoshi; Sano, Daisuke; Funamizu, Naoyuki

    2016-10-01

    In the present study, the bactericidal and virucidal mechanisms in the alkaline disinfection of compost with calcium lime and ash were investigated. Two indicator microorganisms, Escherichia coli and MS2 coliphage, were used as surrogates for enteric pathogens. The alkaline-treated compost with calcium oxide (CaO) or ash resulted primarily in damage to the outer membrane and enzyme activities of E. coli. The alkaline treatment of compost also led to the infectivity loss of the coliphage because of the partial capsid damage and RNA exteriorization due to a raised pH, which is proportional to the amount of alkaline agents added. These results indicate that the alkaline treatment of compost using calcium oxide and ash is effective and can contribute to the safe usage of compost from a mixing type dry toilet. PMID:27562698

  15. 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.

  16. 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.

  17. 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.

  18. 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 < 0.05). The photocatalytic bactericidal effect of TiO2 under LIPUS is useful for sterilizing the contaminated and infected surfaces of metal bio-implants. PMID:27441772

  19. 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.

  20. Oxidative DNA damage caused by pulsed discharge with cavitation on the bactericidal function

    International Nuclear Information System (INIS)

    Plasma-based techniques are expected to have practical use for wastewater purification with a potential for killing contaminated microorganisms and degrading recalcitrant materials. In the present study, we analysed oxidative DNA damage in bacterial cells treated by the plasma to unveil its mechanisms in the bactericidal process. Escherichia coli cell suspension was exposed to the plasma induced by applying an alternating-current voltage of about 1 kV with bubbling formed by water-cavitation, termed pulsed discharge with cavitation. Chromosomal DNA damage, such as double strand break (DSB) and oxidative base lesions, increased proportionally with the applied energy, as determined by electrophoretic and mass spectrometric analyses. Among the base lesions identified, the yields of 8-hydroxyguanine (8-OH-G) and 5-hydroxycytosine (5-OH-C) in chromosomal DNA increased by up to 4- and 15-fold, respectively, compared to untreated samples. The progeny DNA sequences, derived from plasmid DNA exposed to the plasma, indicated that the production rate of 5-OH-C exceeded that of 8-OH-G, as G:C to A:T transitions accounted for 65% of all base changes, but only a few G:C to T:A transversions were observed. The cell viabilities of E. coli cells decreased in direct proportion to increases in the applied energy. Therefore, the plasma-induced bactericidal mechanism appears to relate to oxidative damage caused to bacterial DNA. These results were confirmed by observing the generation of hydroxyl radicals and hydrogen peroxide molecules following the plasma exposure. We also compared our results with the plasma to those obtained with 137Cs γ-rays, as a well-known ROS generator to confirm the DNA-damaging mechanism involved. (paper)

  1. Oxidative DNA damage caused by pulsed discharge with cavitation on the bactericidal function

    Science.gov (United States)

    Kudo, Ken-ichi; Ito, Hironori; Ihara, Satoshi; Terato, Hiroaki

    2015-09-01

    Plasma-based techniques are expected to have practical use for wastewater purification with a potential for killing contaminated microorganisms and degrading recalcitrant materials. In the present study, we analysed oxidative DNA damage in bacterial cells treated by the plasma to unveil its mechanisms in the bactericidal process. Escherichia coli cell suspension was exposed to the plasma induced by applying an alternating-current voltage of about 1 kV with bubbling formed by water-cavitation, termed pulsed discharge with cavitation. Chromosomal DNA damage, such as double strand break (DSB) and oxidative base lesions, increased proportionally with the applied energy, as determined by electrophoretic and mass spectrometric analyses. Among the base lesions identified, the yields of 8-hydroxyguanine (8-OH-G) and 5-hydroxycytosine (5-OH-C) in chromosomal DNA increased by up to 4- and 15-fold, respectively, compared to untreated samples. The progeny DNA sequences, derived from plasmid DNA exposed to the plasma, indicated that the production rate of 5-OH-C exceeded that of 8-OH-G, as G:C to A:T transitions accounted for 65% of all base changes, but only a few G:C to T:A transversions were observed. The cell viabilities of E. coli cells decreased in direct proportion to increases in the applied energy. Therefore, the plasma-induced bactericidal mechanism appears to relate to oxidative damage caused to bacterial DNA. These results were confirmed by observing the generation of hydroxyl radicals and hydrogen peroxide molecules following the plasma exposure. We also compared our results with the plasma to those obtained with 137Cs γ-rays, as a well-known ROS generator to confirm the DNA-damaging mechanism involved.

  2. 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.

  3. 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

  4. Fusion between fluid liposomes and intact bacteria: study of driving parameters and in vitro bactericidal efficacy

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-08-01

    Full Text Available Zhao Wang,1,2* Yufan Ma,1,3,4* Hayssam Khalil,1 Rutao Wang,1–3 Tingli Lu,1 Wen Zhao,1 Yang Zhang,3 Jamin Chen,1,2 Tao Chen,1–3  1Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, 2Shaanxi Liposome Research Center, Xi'an, Shaanxi, 3Xi'an Libang Pharmaceuticals Co, Ltd, Xi'an, 4School of Medicine, Xi'an Jiaotong University, Xi'an, People's Republic of China *These authors contributed equally to this work. Background: Pseudomonas aeruginosa represents a good model of antibiotic resistance. These organisms have an outer membrane with a low level of permeability to drugs that is often combined with multidrug efflux pumps, enzymatic inactivation of the drug, or alteration of its molecular target. The acute and growing problem of antibiotic resistance of bacteria to conventional antibiotics made it imperative to develop new liposome formulations for antibiotics, and investigate the fusion between liposome and bacterium. Methods: In this study, the factors involved in fluid liposome interaction with bacteria have been investigated. We also demonstrated a mechanism of fusion between liposomes (1,2-dipalmitoyl-sn-glycero-3-phosphocholine [DPPC]/dimyristoylphosphatidylglycerol [DMPG] 9:1, mol/mol in a fluid state, and intact bacterial cells, by lipid mixing assay. Results: The observed fusion process is shown to be mainly dependent on several key factors. Perturbation of liposome fluidity by addition of cholesterol dramatically decreased the degree of fusion with P. aeruginosa from 44% to 5%. It was observed that fusion between fluid liposomes and bacteria and also the bactericidal activities were strongly dependent upon the properties of the bacteria themselves. The level of fusion detected when fluid liposomes were mixed with Escherichia coli (66% or P. aeruginosa (44% seems to be correlated to their outer membrane phosphatidylethanolamine (PE phospholipids

  5. Antibiotic Bactericidal Activity Is Countered by Maintaining pH Homeostasis in Mycobacterium smegmatis.

    Science.gov (United States)

    Bartek, I L; Reichlen, M J; Honaker, R W; Leistikow, R L; Clambey, E T; Scobey, M S; Hinds, A B; Born, S E; Covey, C R; Schurr, M J; Lenaerts, A J; Voskuil, M I

    2016-01-01

    Antibiotics target specific biosynthetic processes essential for bacterial growth. It is intriguing that several commonalities connect the bactericidal activity of seemingly disparate antibiotics, such as the numerous conditions that confer broad-spectrum antibiotic tolerance. Whether antibiotics kill in a manner unique to their specific targets or by a universal mechanism is a critical and contested subject. Herein, we demonstrate that the bactericidal activity of diverse antibiotics against Mycobacterium smegmatis and four evolutionarily divergent bacterial pathogens was blocked by conditions that worked to maintain intracellular pH homeostasis. Single-cell pH analysis demonstrated that antibiotics increased the cytosolic pH of M. smegmatis, while conditions that promoted proton entry into the cytosol prevented intracellular alkalization and antibiotic killing. These findings led to a hypothesis that posits antibiotic lethality occurs when antibiotics obstruct ATP-consuming biosynthetic processes while metabolically driven proton efflux is sustained despite the loss of proton influx via ATP synthase. Consequently, without a concomitant reduction in respiratory proton efflux, cell death occurs due to intracellular alkalization. Our findings indicate the effects of antibiotics on pH homeostasis should be considered a potential mechanism contributing to antibiotic lethality. IMPORTANCE Since the discovery of antibiotics, mortality due to bacterial infection has decreased dramatically. However, infections from difficult to treat bacteria such as Mycobacterium tuberculosis and multidrug-resistant pathogens have been on the rise. An understanding of the cascade of events that leads to cell death downstream of specific drug-target interactions is not well understood. We have discovered that killing by several classes of antibiotics was stopped by maintaining pH balance within the bacterial cell, consistent with a shared mechanism of antibiotic killing. Our findings

  6. Fusion between fluid liposomes and intact bacteria: study of driving parameters and in vitro bactericidal efficacy

    Science.gov (United States)

    Wang, Zhao; Ma, Yufan; Khalil, Hayssam; Wang, Rutao; Lu, Tingli; Zhao, Wen; Zhang, Yang; Chen, Jamin; Chen, Tao

    2016-01-01

    Background Pseudomonas aeruginosa represents a good model of antibiotic resistance. These organisms have an outer membrane with a low level of permeability to drugs that is often combined with multidrug efflux pumps, enzymatic inactivation of the drug, or alteration of its molecular target. The acute and growing problem of antibiotic resistance of bacteria to conventional antibiotics made it imperative to develop new liposome formulations for antibiotics, and investigate the fusion between liposome and bacterium. Methods In this study, the factors involved in fluid liposome interaction with bacteria have been investigated. We also demonstrated a mechanism of fusion between liposomes (1,2-dipa lmitoyl-sn-glycero-3-phosphocholine [DPPC]/dimyristoylphosphatidylglycerol [DMPG] 9:1, mol/mol) in a fluid state, and intact bacterial cells, by lipid mixing assay. Results The observed fusion process is shown to be mainly dependent on several key factors. Perturbation of liposome fluidity by addition of cholesterol dramatically decreased the degree of fusion with P. aeruginosa from 44% to 5%. It was observed that fusion between fluid liposomes and bacteria and also the bactericidal activities were strongly dependent upon the properties of the bacteria themselves. The level of fusion detected when fluid liposomes were mixed with Escherichia coli (66%) or P. aeruginosa (44%) seems to be correlated to their outer membrane phosphatidylethanolamine (PE) phospholipids composition (91% and 71%, respectively). Divalent cations increased the degree of fusion in the sequence Fe2+ > Mg2+ > Ca2+ > Ba2+ whereas temperatures lower than the phase transition temperature of DPPC/DMPG (9:1) vesicles decreased their fusion capacity. Acidic as well as basic pHs conferred higher degrees of fusion (54% and 45%, respectively) when compared to neutral pH (35%). Conclusion Based on the results of this study, a possible mechanism involving cationic bridging between bacterial negatively charged

  7. 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

  8. 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

  9. Antibiotic Bactericidal Activity Is Countered by Maintaining pH Homeostasis in Mycobacterium smegmatis

    Science.gov (United States)

    Bartek, I. L.; Reichlen, M. J.; Honaker, R. W.; Leistikow, R. L.; Clambey, E. T.; Scobey, M. S.; Hinds, A. B.; Born, S. E.; Covey, C. R.; Schurr, M. J.; Lenaerts, A. J.

    2016-01-01

    ABSTRACT Antibiotics target specific biosynthetic processes essential for bacterial growth. It is intriguing that several commonalities connect the bactericidal activity of seemingly disparate antibiotics, such as the numerous conditions that confer broad-spectrum antibiotic tolerance. Whether antibiotics kill in a manner unique to their specific targets or by a universal mechanism is a critical and contested subject. Herein, we demonstrate that the bactericidal activity of diverse antibiotics against Mycobacterium smegmatis and four evolutionarily divergent bacterial pathogens was blocked by conditions that worked to maintain intracellular pH homeostasis. Single-cell pH analysis demonstrated that antibiotics increased the cytosolic pH of M. smegmatis, while conditions that promoted proton entry into the cytosol prevented intracellular alkalization and antibiotic killing. These findings led to a hypothesis that posits antibiotic lethality occurs when antibiotics obstruct ATP-consuming biosynthetic processes while metabolically driven proton efflux is sustained despite the loss of proton influx via ATP synthase. Consequently, without a concomitant reduction in respiratory proton efflux, cell death occurs due to intracellular alkalization. Our findings indicate the effects of antibiotics on pH homeostasis should be considered a potential mechanism contributing to antibiotic lethality. IMPORTANCE Since the discovery of antibiotics, mortality due to bacterial infection has decreased dramatically. However, infections from difficult to treat bacteria such as Mycobacterium tuberculosis and multidrug-resistant pathogens have been on the rise. An understanding of the cascade of events that leads to cell death downstream of specific drug-target interactions is not well understood. We have discovered that killing by several classes of antibiotics was stopped by maintaining pH balance within the bacterial cell, consistent with a shared mechanism of antibiotic killing. Our

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

    2014-12-01

    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.

  16. 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.

  17. 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.

  18. 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.

  19. Shape-dependent bactericidal activity of copper oxide nanoparticle mediated by DNA and membrane damage

    Energy Technology Data Exchange (ETDEWEB)

    Laha, Dipranjan; Pramanik, Arindam [Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S C Mallick Road, Kolkata 700032 (India); Laskar, Aparna [CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Jana, Madhurya [Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S C Mallick Road, Kolkata 700032 (India); Pramanik, Panchanan [Department of Chemistry, Indian Institute of Technology, Kharagpur 721302 (India); Karmakar, Parimal, E-mail: pkarmakar_28@yahoo.co.in [Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S C Mallick Road, Kolkata 700032 (India)

    2014-11-15

    Highlights: • Spherical and sheet shaped copper oxide nanoparticles were synthesized. • Physical characterizations of these nanoparticles were done by TEM, DLS, XRD, FTIR. • They showed shape dependent antibacterial activity on different bacterial strain. • They induced both membrane damage and ROS mediated DNA damage in bacteria. - Abstract: In this work, we synthesized spherical and sheet shaped copper oxide nanoparticles and their physical characterizations were done by the X-ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering. The antibacterial activity of these nanoparticles was determined on both gram positive and gram negative bacterial. Spherical shaped copper oxide nanoparticles showed more antibacterial property on gram positive bacteria where as sheet shaped copper oxide nanoparticles are more active on gram negative bacteria. We also demonstrated that copper oxide nanoparticles produced reactive oxygen species in both gram negative and gram positive bacteria. Furthermore, they induced membrane damage as determined by atomic force microscopy and scanning electron microscopy. Thus production of and membrane damage are major mechanisms of the bactericidal activity of these copper oxide nanoparticles. Finally it was concluded that antibacterial activity of nanoparticles depend on physicochemical properties of copper oxide nanoparticles and bacterial strain.

  20. Effect of influenza infection on the phagocytic and bactericidal activities of pulmonary macrophages

    International Nuclear Information System (INIS)

    The effect of mouse-adapted influenza A/PR/8/34 virus on pulmonary macrophage function was evaluated by using an in vitro system which allowed direct virus interaction with macrophages and then separate analysis of the steps required for bacterial clearance by macrophages. Infection of macrophages with this virus resulted in the appearance of a hemagglutinating activity on the macrophage surface; expression of this activity was inhibited by amantadine, 2-deoxyglucose, and cycloheximide and by pretreatment of the virus inoculum with with ultraviolet light and specific antiserum. After influenza infection, net ingestion of viable Staphylococcus aureus by macrophage monolayers was unaltered and there was no change in the fraction of the monolayer which ingested cocci over a wide range of bacterial inputs. Influenza-infected microphages also inactivated intracellular S. aureus at a rate indistinguishable from controls. Therefore, these in vitro studies do not support the hypothesis that the defect in pulmonary antibacterial mechanisms associated with influenza infections results from a direct effect of virus infection on either the phagocytic or bactericidal activity of resistant pulmonary macarophages

  1. 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.

  2. 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.

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

    OpenAIRE

    Starliper, Clifford E.; Barnaby J. Watten; Iwanowicz, Deborah D.; Green, Phyllis A.; Bassett, Noel L.; Adams, Cynthia R

    2015-01-01

    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...

  4. 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.

  5. Polyurethane foams doped with stable silver nanoparticles as bactericidal and catalytic materials for the effective treatment of water

    OpenAIRE

    Domènech Garcia, Berta; Ziegler Benítez, Kharla; Vigués Frantzen, Núria; Olszewski, Wojciech; Marini, Carlo; Mas Gordi, Jordi; Muñoz Tapia, Maria; Muraviev, Dmitri N; Macanás de Benito, Jorge

    2016-01-01

    The development of reusable dual-purpose nanocomposite foams for catalytic and bactericidal water treatment is reported. Small non-aggregated silver nanoparticles were made using Intermatrix Synthesis inside a polyurethane foam, which was chosen as a suitable polymeric matrix due to its high chemical and mechanical stability and industrial applicability. The antibacterial activity of the obtained nanocomposites was evaluated against suspensions of Gram-negative bacteria (E. coli), showing ide...

  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. In Vitro Bactericidal Effects of 625, 525, and 425 nm Wavelength (Red, Green, and Blue) Light-Emitting Diode Irradiation

    OpenAIRE

    Kim, Sangwoo; Kim, Jisun; Lim, Wonbong; Jeon, Sangmi; Kim, OkSu; Koh, Jeong-Tae; Kim, Chang-Su; Choi, Hongran; Kim, Okjoon

    2013-01-01

    Objective: The purpose of this study was to evaluate the relationship of 625, 525, and 425 nm wavelengths, providing average power output and effects on three common pathogenic bacteria. Background data: Ultraviolet (UV) light kills bacteria, but the bactericidal effects of UV may not be unique, as 425 nm produces a similar effect. The bactericidal effects of light-emitting diode (LED) wavelengths such as 625 and 525 nm have not been described. Before conducting clinical trials, the approp...

  8. 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

  9. Radioiodinated DPA-713 imaging correlates with bactericidal activity of tuberculosis treatments in mice.

    Science.gov (United States)

    Ordonez, Alvaro A; Pokkali, Supriya; DeMarco, Vincent P; Klunk, Mariah; Mease, Ronnie C; Foss, Catherine A; Pomper, Martin G; Jain, Sanjay K

    2015-01-01

    Current tools for monitoring response to tuberculosis treatments have several limitations. Noninvasive biomarkers could accelerate tuberculosis drug development and clinical studies, but to date little progress has been made in developing new imaging technologies for this application. In this study, we developed pulmonary single-photon emission computed tomography (SPECT) using radioiodinated DPA-713 to serially monitor the activity of tuberculosis treatments in live mice, which develop necrotic granulomas and cavitary lesions. C3HeB/FeJ mice were aerosol infected with Mycobacterium tuberculosis and administered either a standard or a highly active bedaquiline-containing drug regimen. Serial (125)I-DPA-713 SPECT imaging was compared with (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and standard microbiology. Ex vivo studies were performed to characterize and correlate DPA-713 imaging with cellular and cytokine responses. Pulmonary (125)I-DPA-713 SPECT, but not (18)F-FDG PET, was able to correctly identify the bactericidal activities of the two tuberculosis treatments as early as 4 weeks after the start of treatment (P < 0.03). DPA-713 readily penetrated the fibrotic rims of necrotic and cavitary lesions. A time-dependent decrease in both tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) levels was observed with treatments, with (125)I-DPA-713 SPECT correlating best with tissue TNF-α levels (ρ = 0.94; P < 0.01). (124)I-DPA-713 was also evaluated as a PET probe and demonstrated a 4.0-fold-higher signal intensity in the infected tuberculous lesions than uninfected controls (P = 0.03). These studies provide proof of concept for application of a novel noninvasive imaging biomarker to monitor tuberculosis treatments, with the potential for application for humans. PMID:25403669

  10. 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.

  11. 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.

  12. 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.

  13. Synergistic bactericidal effect by combined exposure to Ag nanoparticles and UVA

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaoxu; Toyooka, Tatsushi; Ibuki, Yuko, E-mail: ibuki@u-shizuoka-ken.ac.jp

    2013-08-01

    Broad and strong antimicrobial properties of silver (Ag) have been used for biomedical applications, water treatment, etc. In this study, a synergistic antibacterial effect between Ag nanoparticles (AgNPs) and ultraviolet (UV) light was examined. AgNPs (< 0.1 μm) with subsequent exposure to UVA (320–400 nm) showed pronounced toxicity in Escherichia coli, but micro-sized Ag particles (> 1 μm) with UVA and AgNPs with UVB (280–325 nm) did not. As significant bactericidal activity was also exhibited by hydrogen peroxide-treated AgNPs, the surface oxidation of AgNPs caused by UVA irradiation was considered to contribute to the enhanced antibacterial effect. Although no difference in NP-incorporation rates was observed with or without the surface oxidation of AgNPs, a particle size of less than 0.1 μm was a factor for AgNPs uptake and an essential requirement for the antimicrobial function of Ag particles. Incorporated AgNPs oxidized by UVA irradiation released larger amounts of Ag ion inside cells than reduced AgNPs, which reacted with intercellular molecules having –SH groups such as glutathione. The synergistic use of AgNPs and UVA could become a powerful tool with broad antimicrobial applications. Highlights: • Combined treatment with AgNPs and UV achieved a remarkable antibacterial effect in E. coli. • For the antibacterial effect, it is necessary to satisfy the following requirements: • 1) Translocation of nano-sized Ag particles inside E. coli. • 2) Oxidation of AgNPs by UVA, and extensive and persistent release of Ag{sup +} inside E. coli. • Ag{sup +} released inside cells reacted with intercellular molecules having –SH groups such as GSH.

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

    Science.gov (United States)

    Yemmireddy, Veerachandra K; Hung, Yen-Con

    2015-07-01

    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.

  15. 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.

  16. 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.

  17. 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.

  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. 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

  20. [Detection of bactericidal antibody in the breast milk of a mother infected with enterohemorrhagic Escherichia coli O157:H7].

    Science.gov (United States)

    Adachi, E; Tanaka, H; Toyoda, N; Takeda, T

    1999-05-01

    A 21 years-old pregnant woman developed diarrhea, fresh bloody stools and abdominal pain on April 6th 1997 at 32 weeks of gestation, and was admitted to the hospital on April 11th. The stool culture on admission was positive for enterohemorrhagic Escherichia coli (EHEC) O157:H7 (Stx1 and 2). Clinical laboratory data during admission showed only slight elevation of beta-microglobulin and N-acetyl glucosaminidase in the urine, and no neurological or hemolytic symptoms were seen. After the antibiotic and lactobacillus administration, all her symptoms were relieved and no abnormal findings in pregnancy were observed. She delivered a baby girl normally on May 30th. Serum (between 41 and 120 days from the onset) and milk (between 4 and 64 days post partum) samples from the mother, and serum (64 days of age) from a baby and cord blood were obtained to monitor the immune status against EHEC O157:H7 and against Shiga toxins (Stx). Anti-E. coli O157 LPS antibodies (IgA, G and M) were assayed by the ELISA method. Neutralizing anti-Stx antibodies were measured by using ACHN cell cytotoxicity assay. In the colostrum and mature milk, high levels of IgA and IgM, and no IgG antibodies against EHEC O157 LPS were detected. In one of the control colostrum samples obtained from 4 healthy mothers IgA antibody against EHEC O157 LPS was detected. To assess the potency of protection against EHEC O157:H7 by the breast milk, we monitored it by the bactericidal activity for the organism under complement-coincubation experiment, and by the neutralization test for the Stx cytotoxicity. As a result, breast milk samples (both colostrum and mature milk) from a patient were demonstrated to kill the organisms. One of 4 healthy milk samples, showed bactericidal activity though it was negative in O157-LPS antibody. This bactericidal activity seen in one healthy colostrum is possibly due to a nonspecific reaction caused by non-O157 E. coli infection. From these observations, it was suggested that the

  1. 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.

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

    Science.gov (United States)

    Starliper, Clifford E; Watten, Barnaby J; Iwanowicz, Deborah D; Green, Phyllis A; Bassett, Noel L; Adams, Cynthia R

    2015-05-01

    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 × 10(6) cfu/mL with a range 1.02 × 10(5)-1.60 × 10(8) 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. PMID:26257948

  3. 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.

  4. Bactericidal activity of moxifloxacin against multidrug-resistant Streptoccocus pneumoniae at clinically achievable serum and epithelial lining fluid concentrations compared with three other antimicrobials.

    Science.gov (United States)

    Cafini, Fabio; Alou, Luis; Sevillano, David; Valero, Eva; Prieto, José

    2004-10-01

    Time-kill studies compared the activities of moxifloxacin with those of levofloxacin, azithromycin and amoxicillin-clavulanate against 10 pneumococcal strains with various drug susceptibilities. Three Streptococcus pneumoniae strains were resistant to moxifloxacin: 6, 7 and 2 strains were resistant to levofloxacin, azithromycin and amoxicillin-clavulanate, respectively. Of these, 1 strain was resistant to all antimicrobial agents studied. Moxifloxacin and amoxicillin-clavulanate were bactericidal after 24h at serum Cmax levels against 9 and 8 strains, respectively, while levofloxacin and azithromycin were bactericidal against 3 and 2 strains, respectively. A higher activity was only observed for amoxicillin-clavulanate for logarithmic phase cultures at 1, 4 and 8h compared with stationary phase organisms. Amoxicillin-clavulanate and moxifloxacin were bactericidal at free serum levels (protein unbound) after 24h against 8 and 3 strains, respectively. Moxifloxacin was bactericidal at epithelial lining fluid levels against all strains at 24h, including one moxifloxacin, amoxicillin-clavulanate and azithromycin-resistant strain; lower levels of bactericidal activity was observed for levofloxacin, azithromycin and amoxicillin-clavulanate against 7, 2 and 4 strains, respectively. This demonstrated the importance of moxifloxacin tissue levels. PMID:15380257

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

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

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    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.

  14. 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.

  15. 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.

  16. 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.

  17. Short-term storage does not affect the quantitative yield of Mycobacterium tuberculosis in sputum in early-bactericidal-activity studies

    NARCIS (Netherlands)

    Kolwijck, E.; Mitchell, M.; Venter, A.; Friedrich, S.O.; Dawson, R.; Diacon, A.H.

    2013-01-01

    Early-bactericidal-activity (EBA) studies measure the change in mycobacterial load in sputum over time to evaluate antituberculosis drugs. We investigated whether a delay in sputum processing influences the quantitative results of sputum mycobacterial culture. We identified pretreatment smear-positi

  18. 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.

  19. 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.

  20. 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.

  1. Bactericidal Compounds Controlling Growth of the Plant Pathogen Pseudomonas syringae pv. actinidiae, Which Forms Biofilms Composed of a Novel Exopolysaccharide

    Science.gov (United States)

    Ghods, Shirin; Sims, Ian M.; Moradali, M. Fata

    2015-01-01

    Pseudomonas syringae pv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused by P. syringae pv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain of P. syringae pv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed by P. syringae pv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced by P. syringae pv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence that P. syringae pv. actinidiae NZ V-13 produces two polysaccharides, a branched α-d-rhamnan with side chains of terminal α-d-Fucf and an α-d-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% of P. syringae pv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment of P. syringae pv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic against P. syringae pv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition of P. syringae pv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds. PMID:25841017

  2. 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 < 0.001). Taken together, the semi-automated SBA might be efficient, accurate, sensitive, and specific enough to measure functional antibody titers against S. Typhi in sera from human subjects immunized with typhoid vaccines. PMID:27216239

  3. 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. PMID:26952491

  4. 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.

  5. 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. PMID:9627966

  6. 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.

  7. 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.

  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. PMID:27102839

  9. The Human Antimicrobial Protein Bactericidal/Permeability-Increasing Protein (BPI) Inhibits the Infectivity of Influenza A Virus

    Science.gov (United States)

    Pinkenburg, Olaf; Meyer, Torben; Bannert, Norbert; Norley, Steven; Bolte, Kathrin; Czudai-Matwich, Volker; Herold, Susanne; Gessner, André; Schnare, Markus

    2016-01-01

    In addition to their well-known antibacterial activity some antimicrobial peptides and proteins (AMPs) display also antiviral effects. A 27 aa peptide from the N-terminal part of human bactericidal/permeability-increasing protein (BPI) previously shown to harbour antibacterial activity inhibits the infectivity of multiple Influenza A virus strains (H1N1, H3N2 and H5N1) the causing agent of the Influenza pneumonia. In contrast, the homologous murine BPI-peptide did not show activity against Influenza A virus. In addition human BPI-peptide inhibits the activation of immune cells mediated by Influenza A virus. By changing the human BPI-peptide to the sequence of the mouse homologous peptide the antiviral activity was completely abolished. Furthermore, the human BPI-peptide also inhibited the pathogenicity of the Vesicular Stomatitis Virus but failed to interfere with HIV and measles virus. Electron microscopy indicate that the human BPI-peptide interferes with the virus envelope and at high concentrations was able to destroy the particles completely. PMID:27273104

  10. Nanoscale Mo- MoO3 Entrapped in Engineering Thermoplastic: Inorganic Pathway to Bactericidal and Fungicidal Action.

    Science.gov (United States)

    Qureshi, Nilam; Chaudhari, Ravindra; Mane, Pramod; Shinde, Manish; Jadakar, Sandesh; Rane, Sunit; Kale, Bharat; Bhalerao, Anand; Amalnerkar, Dinesh

    2016-04-01

    In our contemporary endeavor, metallic molybdenum (Mo) and semiconducting molybdenum trioxide (MoO3) nanostructures have been simultaneously generated via solid state reaction between molybdenum (III) chloride (MoCl3) and polyphenylene sulfide (PPS) at 285 (°)C in unimolar ratio for different time durations, namely, 6 h, 24 h, and 48 h. The resultant nanocomposites (NCs) revealed formation of predominantly metallic Mo for all the samples. However, MoO3 gradually gained prominent position as secondary phase with rise in reaction time. The present study was intended to investigate the antibacterial potential of metal-metal oxide-polymer NCs, i.e., Mo- MoO3-PPS against microorganisms, viz., Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, and Aspergillus fumigatus. The antibacterial activity of the NCs was evaluated by agar well diffusion investigation. Maximum sensitivity concentrations of NCs were determined by finding out minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC). Moreover, the NCs prepared at reaction time of 48 h exhibited best MBC values and were tested with time kill assay which revealed that the growth of S. aureus was substantially inhibited by Mo- MoO3-PPS NCs. This synchronized formation of Mo- MoO3 nanostructures in an engineering thermoplastic may have potential antimicrobial applications in biomedical devices and components. Prima facie results on antifungal activity are indicative of the fact that these materials can show anti-cancer behavior. PMID:27164597

  11. Minimum bactericidal concentration of phenols extracted from oil vegetation water on spoilers, starters and food-borne bacteria

    Directory of Open Access Journals (Sweden)

    Luca Fasolato

    2015-05-01

    Full Text Available The aim of the study was to assess the in vitro effect of phenols extracted from oil vegetation water (PEOW on several food-borne strains. Antibacterial activity of PEOW was based on the minimum bactericidal concentration (MBC on microtitre assay. The taxa tested were: Staphylococcus (n. 5, Listeria (n. 4, Escherichia (n. 2, Salmonella (n. 1, Pseudomonas (n. 3, Lactobacillus (n. 2 and Pediococcus (n. 1. S. aureus and L. monocytogens showed the lowest level of resistance to PEOW (MBC=1.5-3 mg/mL. In contrast, the Gram negative strains (e.g. S. Typhimurium and Pseudomonas spp. were in some cases unaffected by the tested doses and the MBCs ranged between 6 to 12 mg/mL. Starter cultures were dramatically reduced on growth (e.g. Staphylococcus xylosus; 0.75 mg/mL MBC. The thresholds for pathogenic strains could be considered for further applications of PEOW in food models (e.g. shelf life or challenge test studies.

  12. 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.

  13. 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.

  14. Biological and bactericidal properties of Ag-doped bioactive glass in a natural extracellular matrix hydrogel with potential application in dentistry

    OpenAIRE

    Y-Y Wang; X Chatzistavrou; D Faulk; Badylak, S; Zheng, L; S. Papagerakis; Ge, L.; H. Liu; Papagerakis, P.

    2015-01-01

    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 impl...

  15. Intranasal Delivery of Group B Meningococcal Native Outer Membrane Vesicle Vaccine Induces Local Mucosal and Serum Bactericidal Antibody Responses in Rabbits

    OpenAIRE

    Shoemaker, David R.; Saunders, Nancy B.; Brandt, Brenda L.; Moran, E. Ellen; LaClair, Andrew D.; Zollinger, Wendell D.

    2005-01-01

    We have previously shown that intranasal immunization of mice with meningococcal native outer membrane vesicles (NOMV) induces both a good local mucosal antibody response and a good systemic bactericidal antibody response. However, in the intranasal mouse model, some of the NOMV entered the lung and caused an acute granulocytic response. We therefore developed an alternate animal model using the rabbit. This model reduces the probability of lung involvement and more closely mimics intranasal ...

  16. Bactericidal Activities of Daptomycin, Quinupristin-Dalfopristin, and Linezolid against Vancomycin-Resistant Staphylococcus aureus in an In Vitro Pharmacodynamic Model with Simulated Endocardial Vegetations

    OpenAIRE

    Cha, Raymond; Brown, William J.; Rybak, Michael J.

    2003-01-01

    In search of treatment alternatives against vancomycin-resistant S. aureus (VRSA), an in vitro pharmacodynamic model with simulated endocardial vegetations incorporating protein and a high inoculum was used to simulate daptomycin, linezolid, quinupristin-dalfopristin, and vancomycin against the Michigan VRSA strain. Daptomycin and quinupristin-dalfopristin exhibited the greatest bacterial reductions, and all tested agents except vancomycin exhibited bactericidal activity against the VRSA.

  17. Bactericidal interactions of a beta-lactam and beta-lactamase inhibitors in experimental Pseudomonas aeruginosa endocarditis caused by a constitutive overproducer of type Id beta-lactamase.

    OpenAIRE

    Bayer, A S; Selecky, M; Babel, K; Hirano, L; Yih, J; Parr, T R

    1987-01-01

    We investigated the in vitro and in vivo effects of a combination of a beta-lactam (ceftazidime) and a beta-lactamase inhibitor (dicloxacillin) to synergistically kill a ceftazidime-resistant variant, Pseudomonas aeruginosa PA-48, which overproduces type Id cephalosporinase constitutively. In vitro, dicloxacillin plus ceftazidime exerted bactericidal synergy at approximately 10(5) CFU/ml of inoculum (but not at approximately 10(7)-CFU inoculum), whereas other beta-lactamase inhibitors (sulbac...

  18. 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.

  19. 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.

  20. Green synthesis and characterization of Carica papaya leaf extract coated silver nanoparticles through X-ray diffraction, electron microscopy and evaluation of bactericidal properties.

    Science.gov (United States)

    Banala, Rajkiran Reddy; Nagati, Veera Babu; Karnati, Pratap Reddy

    2015-09-01

    The evolution of nanotechnology and the production of nanomedicine from various sources had proven to be of intense value in the field of biomedicine. The smaller size of nanoparticles is gaining importance in research for the treatment of various diseases. Moreover the production of nanoparticles is eco-friendly and cost effective. In the present study silver nanoparticles were synthesized from Carica papaya leaf extract (CPL) and characterized for their size and shape using scanning electron microscopy and transmission electron microscopy, respectively. Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS/EDX) and X-ray diffraction spectroscopy (XRD) were conducted to determine the concentration of metal ions, the shape of molecules. The bactericidal activity was evaluated using Luria Bertani broth cultures and the minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were estimated using turbidimetry. The data analysis showed size of 50-250 nm spherical shaped nanoparticles. The turbidimetry analysis showed MIC and MBC was >25 μg/mL against both Gram positive and Gram negative bacteria in Luria Bertani broth cultures. In summary the synthesized silver nanoparticles from CPL showed acceptable size and shape of nanoparticles and effective bactericidal activity. PMID:26288570

  1. 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.

  2. Interactions of Quinupristin-Dalfopristin with Eight Other Antibiotics as Measured by Time-Kill Studies with 10 Strains of Staphylococcus aureus for Which Quinupristin-Dalfopristin Alone Was Not Bactericidal

    OpenAIRE

    Fuchs, Peter C.; Barry, Arthur L.; Brown, Steven D.

    2001-01-01

    Quinupristin-dalfopristin (Q-D) and eight other antimicrobial agents were tested alone and in combination with Q-D in time-kill studies against 10 strains of macrolide-lincosamide-streptogramin B-resistant Staphylococcus aureus. Although Q-D is normally a bactericidal drug, it was only bacteriostatic for these isolates. Gentamicin alone was bactericidal against 7 of the 10 strains, and Q-D did not alter that killing effect. However, when vancomycin, cefepime, ceftazidime, imipenem, piperacill...

  3. 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.

  4. Cell cycle arrest evidence, parasiticidal and bactericidal properties induced by L-amino acid oxidase from Bothrops atrox snake venom.

    Science.gov (United States)

    de Melo Alves Paiva, Raquel; de Freitas Figueiredo, Raquel; Antonucci, Gilmara Ausech; Paiva, Helder Henrique; de Lourdes Pires Bianchi, Maria; Rodrigues, Kelly C; Lucarini, Rodrigo; Caetano, Renato Cesar; Linhari Rodrigues Pietro, Rosemeire Cristina; Gomes Martins, Carlos Henrique; de Albuquerque, Sérgio; Sampaio, Suely Vilela

    2011-05-01

    The present article describes an l-amino acid oxidase from Bothrops atrox snake venom as with antiprotozoal activities in Trypanosoma cruzi and in different species of Leishmania (Leishmania braziliensis, Leishmania donovani and Leishmania major). Leishmanicidal effects were inhibited by catalase, suggesting that they are mediated by H(2)O(2) production. Leishmania spp. cause a spectrum of diseases, ranging from self-healing ulcers to disseminated and often fatal infections, depending on the species involved and the host's immune response. BatroxLAAO also displays bactericidal activity against both Gram-positive and Gram-negative bacteria. The apoptosis induced by BatroxLAAO on HL-60 cell lines and PBMC cells was determined by morphological cell evaluation using a mix of fluorescent dyes. As revealed by flow cytometry analysis, suppression of cell proliferation with BatroxLAAO was accompanied by the significant accumulation of cells in the G0/G1 phase boundary in HL-60 cells. BatroxLAAO at 25 μg/mL and 50 μg/mL blocked G0-G1 transition, resulting in G0/G1 phase cell cycle arrest, thereby delaying the progression of cells through S and G2/M phase in HL-60 cells. This was shown by an accentuated decrease in the proportion of cells in S phase, and the almost absence of G2/M phase cell population. BatroxLAAO is an interesting enzyme that provides a better understanding of the ophidian envenomation mechanism, and has biotechnological potential as a model for therapeutic agents. PMID:21300133

  5. 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

  6. 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

  7. Randomized Dose-Ranging Study of the 14-Day Early Bactericidal Activity of Bedaquiline (TMC207) in Patients with Sputum Microscopy Smear-Positive Pulmonary Tuberculosis

    OpenAIRE

    Diacon, Andreas H; Dawson, Rodney; Von Groote-Bidlingmaier, Florian; Symons, Gregory; Venter, Amour; Donald, Peter R.; Conradie, Almari; Erondu, Ngozi; Ginsberg, Ann M.; Egizi, Erica; Winter, Helen; De Becker, Piet; Mendel, Carl M.

    2013-01-01

    Bedaquiline is a new antituberculosis agent targeting ATP synthase. This randomized, double-blinded study enrolling 68 sputum smear-positive pulmonary tuberculosis patients evaluated the 14-day early bactericidal activity of daily doses of 100 mg, 200 mg, 300 mg, and 400 mg bedaquiline, preceded by loading doses of 200 mg, 400 mg, 500 mg, and 700 mg, respectively, on the first treatment day and 100 mg, 300 mg, 400 mg, and 500 mg on the second treatment day. All groups showed activity with a m...

  8. Identification and characterization of a phospholipase A2 from the venom of the Saw-scaled viper: Novel bactericidal and membrane damaging activities.

    Science.gov (United States)

    Perumal Samy, Ramar; Gopalakrishnakone, P; Bow, Ho; Puspharaj, Peter N; Chow, Vincent T K

    2010-12-01

    Phospholipase A(2) (PLA(2)), a common toxic component of snake venom, has been implicated in various pharmacological effects. In this study, a basic myotoxic PLA(2), named EcTx-I was isolated from Echis carinatus snake venom by using gel filtration on Superdex G-75, and reverse phase HPLC on C18 and C8 Sepharose columns. PLA(2), EcTx-I was 13,861.72 molecular weight as estimated by MALDI-TOF (15 kD by SDS-PAGE), and consisted of 121 amino acid residues cross-linked by seven disulfide bonds. The N-terminal sequences revealed significant homology with basic myotoxic PLA(2)s from other snake venoms. The purified PLA(2) EcTx-I was evaluated (250 μg/ml) for bactericidal activity of a wide variety of human pathogens against Burkholderia pseudomallei (KHW&TES), Enterobacter aerogenes, Escherichia coli, Proteus vulgaris, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus. EcTx-I showed strong antibacterial activity against B. pseudomallei (KHW) and E. aerogenes among the tested bacteria. Other Gram-negative and Gram-positive bacteria showed only a moderate effect. However, the Gram-positive bacterium E. aerogenes failed to show any effect on EcTx-I protein at tested doses. The most significant bacteriostatic and bactericidal effect of EcTx-I was observed at MICs of >15 μg/ml against (B. pseudomallei, KHW) and MICs >30 μg/ml against E. aerogenes. Mechanisms of bactericidal and membrane damaging effects were proved by ultra-structural analysis. EcTx-I was able to induce cytotoxicity on THP-1 cells in vitro as well as lethality in BALB/c mice. EcTx-I also induced mild myotoxic effects on mouse skin, but was devoid of hemolytic effects on human erythrocytes up to 500 μg/ml. It is shown that the toxic effect induced by E. carinatus venom is due to the presence of myotoxic PLA(2) (EcTx-I). The result also corroborates the hypothesis of an association between toxic and enzymatic domains. In conclusion, EcTx-I displays a heparin binding C-terminal region

  9. 血清抗b型流感嗜血杆菌磷酸多聚核糖基核糖醇抗体杀菌活性体外检测方法的建立%Development of Serum Bactericidal Assay In Vitro for Determination of Bactericidal Activity of Serum Anti-Haemophilus influenzae Type b Polyribosylribitol Phosphate Antibody

    Institute of Scientific and Technical Information of China (English)

    乔瑞洁; 李亚南; 赵志强; 刘佳; 王浩; 史晓玲; 谭小梅; 杜送田; 谢贵林

    2011-01-01

    Objective To develop a serum bactericidal assay(SBA) in vitro for determination of bactericidal activity of serum anti-Haemophilus infiuenzae type b (Hib) polyribosylribitol phosphate (PRP) antibody. Methods A SBA method was developed by screening of complement and index bacterial strain, and verified for stability, specificity and precision. Results Hib-EAGAN strain as an index strain and Hib-pesitive serum showed high bactericidal specificity, of bath of which the non-specific bactericidal rates were 0. of the four batches of complements provided by Pel-Freez, Lot 17830 showed high stability and specificity. The result of verification showed high stability and specificity of the developed Hib-SBA system, of which the CV of precision was 16% ~ 28%. Conclusion The SBA in vitro for determination of bactericidal activity of serum anti-Hib-PRP was successfully developed, which was of high-throughput, was time-saving and easy to be standardized.%目的 建立免疫血清中抗b型流感嗜血杆菌(Haemophilus influenzae type b,Hib)磷酸多聚核糖基核糖醇(Polyribosylribitol phosphate,PRP)抗体体外血清杀菌试验(Serum bacterialcid assay,SBA)方法.方法 通过对补体和指示菌株的筛选,建立体外测定血清中抗Hib-PRP抗体杀菌试验方法,并对实验体系的耐变性、特异性及精密性进行验证.结果 指示菌Hib-EAGAN株与Hib阳性血清显示出良好的杀菌特异性,其平均非特异性杀菌率为0;Pel-Freez公司提供的4批补体中,批号为17830的补体具有良好的杀菌稳定性和特异性;经验证,建立的Hib-SBA体系具有良好的耐变性和特异性,其精密性CV值在16%~28%之间.结论 成功建立了血清抗Hib-PRP抗体杀菌活性体外检测方法,该方法具有检测样本量大、省时、易标准化等优点.

  10. Antimicrobial activity of human α-defensin 6 analogs: insights into the physico-chemical reasons behind weak bactericidal activity of HD6 in vitro.

    Science.gov (United States)

    Mathew, Basil; Nagaraj, Ramakrishnan

    2015-11-01

    Human α-defensin 6 (HD6), unlike other mammalian defensins, does not exhibit bactericidal activity, particularly against aerobic bacteria. Monomeric HD6 has a tertiary structure similar to other α-defensins in the crystalline state. However, the physico-chemical reasons behind the lack of antibacterial activity of HD6 are yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD6 analogs. A linear analog of HD6, in which the distribution of arginine residues was similar to active α-defensins, shows broad-spectrum antimicrobial activity, indicating that atypical distribution of arginine residues contributes to the inactivity of HD6. Peptides spanning the N-terminal cationic segment were active against a wide range of organisms. Antimicrobial potency of these shorter analogs was further enhanced when myristic acid was conjugated at the N-terminus. Cytoplasmic localization of the analogs without fatty acylation was observed to be necessary for bacterial killing, while they exhibited fungicidal activity by permeabilizing Candida albicans membranes. Myristoylated analogs and the linear full-length arginine analog exhibited activity by permeabilizing bacterial and fungal membranes. Our study provides insights into the lack of bactericidal activity of HD6 against aerobic bacteria. PMID:26400692

  11. Bactericidal activity and mechanism of AgI/AgBr/BiOBr(0.75)I(0.25) under visible light irradiation.

    Science.gov (United States)

    Liang, Jialiang; Deng, Jun; Li, Mian; Tong, Meiping

    2016-02-01

    The AgI/AgBr/BiOBr0.75I0.25 nanocomposites were synthesized by a solvothermal process, followed by an in-situ ion exchange reaction. The disinfection activities of the as-synthesized photocatalyst to model cell type, Gram-negative Escherichia coli (E. coli), were investigated under visible light irradiation condition (λ≥400 nm). Results showed that 80 mg/L AgI/AgBr/BiOBr0.75I0.25 could completely inactivate 3×10(7) CFU mL(-1)E. coli cells within 30 min under visible light irradiation. Moreover, the bactericidal mechanisms involved in the photocatalytic disinfection process were systematically investigated. Ag(+) ions released from the nanocomposites negligibly contributed to the bactericidal activity, while active species including h(+), e(-) and ·O2(-) played important roles in the disinfection system. Direct contact of bacterial cells and nanoparticles was found to be the prerequisite for both the generation of ·O2(-) and the disinfection processes. The disruption of cell membrane and emission of cytoplasm directly inactivated E. coli cells. In addition, AgI/AgBr/BiOBr0.75I0.25 exhibited strong antibacterial activity toward E. coli even in four consecutive reused cycles. PMID:26674838

  12. 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.

  13. 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 (p6.5logCFU/cm(2) reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7logCFU/cm(2) reduction; NaCl, <0.5logCFU/cm(2) reduction). Confocal laser scanning microscopy images of propidium iodide-treated cells showed that PA (0.4%) plus NaCl (2-4%) had marked membrane permeabilizing effects. These results suggest that a sanitizer that combines these two naturally occurring antimicrobial agents may be useful to food safety managers who encounter thick biofilm formation in food processing environments. PMID:27043385

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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. PMID:27317452

  19. 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

    2016-01-01

    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. 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. PMID:26939573

  20. 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.

  1. Inhibition of Escherichia coli by bovine colostrum and post-colostral milk. I. Complement-mediated bactericidal activity of antibodies to a serum susceptible strain of E. coli of the serotype O 111.

    Science.gov (United States)

    Reiter, B; Brock, J H

    1975-01-01

    Bovine colostral whey diulted in unheated bovine milk or in Kolmer saline containing 5 per cent pre-colostral calf serum was bactericidal for Escherichia coli NCTC 9703 (serotype O 111). Whey diluted in saline without pre-colostral calf serum was inactive. Bactericidal activity was abolished by heating at 56 degrees for 30 minutes or by pre-incubating with N-acetyl-L-tyrosine ethylester, indicating that complement present in milk or pre-colostral calf serum was involved in the bactericidal activity. Undiluted colostral whey was inactive even in the presence of up to 20 per cent pre-colostral calf serum, probably due to a prozone effect. Milk heated at 80 degrees for 10 minutes was also shown to have a limited anti-complementary effect. Post-colostral milk from some cows had bactericidal activity, whereas similar milks from other cows were either inactive or active only after addition of pre-colostral calf serum, indicating that antibodies to E. coli or complement or both may or may not be present in the post-colostral milk of different cows. The implications of these findings in relation to the bacterial flora of the intestinal tract of neonates are discussed. PMID:1090521

  2. 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.

  3. Microbial and chemical origins of the bactericidal activity of thermally treated yellow mustard powder toward Escherichia coli O157:H7 during dry sausage ripening.

    Science.gov (United States)

    Luciano, Fernando B; Belland, Julie; Holley, Richard A

    2011-01-31

    Work examines the origin of bactericidal activity in mustard flour and explores the relative contribution from starter cultures, E. coli O157:H7 itself and other sources. Bacteria can degrade naturally occurring glucosinolates in mustard and form isothiocyanates with antimicrobial activity. In the present work, 24 starter cultures (mostly from commercial mixtures) were screened for their capacity to decompose the glucosinolate, sinalbin. The most active pair, Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123 M, were used together for the production of dry fermented sausage contaminated with E. coli O157:H7 (~6.5 log CFU/g). They were compared to industrial starters used previously (P. pentosaceus UM 116P and S. carnosus UM 109 M) for their reduction of E. coli O157:H7 viability. Sausage batches containing hot mustard powder (active myrosinase), cold mustard powder (inactivated myrosinase), autoclaved mustard powder (inactivated myrosinase) and no mustard flour (control) were prepared. Interestingly, both pairs of starter cultures yielded similar results. Elimination of E. coli O157:H7 (>5 log CFU/g) occurred after 31 days in the presence of hot flour and in 38 days when the cold flour was added. Reductions >5 log CFU/g of the pathogen did not occur (up to 38 days) in the control group. It was found that E. coli O157:H7 itself had a greater effect on sinalbin conversion than either pair of starter cultures, and glucosinolate degradation by the starter cultures was less important in determining E. coli survival. The autoclaved powder caused more rapid bactericidal action against E. coli O157:H7, yielding a >5 log CFU/g reduction in 18 days. This may have been a result of the formation and/or release of antimicrobial substances by the autoclave treatment. Autoclaved mustard powder could potentially solve an important challenge facing the meat industry as it strives to manufacture safe dry fermented sausages. PMID:21146240

  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. Characterization and relative photonic efficiencies of a new nanocarbon/TiO2 composite photocatalyst designed for organic dye decomposition and bactericidal activity

    International Nuclear Information System (INIS)

    Two kinds of nanocarbon/TiO2 composite photocatalysts were synthesized using an MCPBA oxidation method, employing MWCNT (multi-wall carbon nanotubes) and C60 as nanocarbon sources and TNB (titanium (IV) n-butoxide) as a titanium dioxide source. From the XRD patterns of the composites, structural variations revealed the C60/TiO2 composite having a mixture of anatase and rutile forms, with the MWCNT/TiO2 composite presenting only the anatase phase. Elemental analysis indicated a predominance of carbon and Ti metal peaks over any other element. From the SEM results, the TiO2 particles were dispersed regularly on the fullerene surface with large clusters bearing irregular agglomerate dispersions. However, the MWCNT/TiO2 showed homogenous distributions with only individual MWCNT, covered with TiO2 and without any jam-like aggregates between the two. According to the photocatalytic results, the relationship of the -ln (c/c0) of the solution products of the organic dye, methylene blue (MB), as a function of time under UV irradiation, showed linearity properties with first-order kinetics and an excellent photodegradation effect. From the measured bactericidal effects, the inhibition zone was defined by the halo method with the curves of E. coli inactivation denoting effectiveness of the nanocarbon/TiO2 composites in the sunlight.

  6. Design, synthesis and in vitro bactericidal/fungicidal screening of some vanadyl(IV)complexes with mono- and di-substituted ONS donor triazoles.

    Science.gov (United States)

    Sumrra, Sajjad H; Hanif, Muhammad; Chohan, Zahid H

    2015-01-01

    A new series of anti-bacterial and anti-fungal mono- and di-substituted triazoles (L(1))-(L(6)) have been synthesized and characterized on the basis of their physical, spectral and analytical data. The ligands (L(1))-(L(6)) on reaction with vanadyl(IV) sulphate led to the formation of vanadyl(IV) metal complexes (1)-(4). The structure of the complexes has been established on the basis of their physical, spectral and elemental analyses data. The synthesized ligands and their vanadyl(IV) complexes have been screened in vitro for anti-bacterial activity against six bacterial species such as, Escherichia coli (ATCC 25922), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (ATCC 27853), Salmonella typhi (ATCC 14028), Staphylococcus aureus (ATCC 25923) and Bacillus subtilis (ATCC 6051) and for in vitro anti-fungal activity against six fungal strains, Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata. The screening results showed the vanadyl complexes to be more bactericidal/fungicidal against one or more bacterial/fungal species. The synthesized compounds were also subjected to brine shrimp bioassay for scrutinizing their cytotoxicity. PMID:25716124

  7. 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. PMID:25928035

  8. Enhanced bactericidal effect of enterocin A in combination with thyme essential oils against L. monocytogenes and E. coli O157:H7.

    Science.gov (United States)

    Ghrairi, Taoufik; Hani, Khaled

    2015-04-01

    The combined effects of enterocin A with Thymus vulgaris essential oils (EOs) against Listeria monocytogenes and Escherichia coli O157:H7 were investigated in vitro by enumeration of surviving populations of testing pathogens and minimal inhibitory concentration (MIC) determination. Enterocin A was purified to homogeneity by RP-HPLC from the culture fluid of Enterococcus strain and thyme EOs were extracted from local Thymus vulgaris plants. The major constituent of thyme EOs oils determined by GC-MS was thymol (78.4 %). Combination of enterocin A with thyme EOs showed an enhanced bactericidal effect against Listeria monocytogenes. Checkerboard assay and isobologram construction displayed a synergistic interaction between these compounds against Listeria (FIC index thyme EOs decreased threefold (from 3.6 to 1.2 μg/ml). Treatments with enterocin A alone did not affect the growth of the enteric pathogen E. coli O157:H7. However, the addition of thyme EOs and enterocin A yielded a synergistic antimicrobial effect against E. coli (MIC thyme EOs decrease from 2.2 to 0.71 μg/ml). This is the first report on the combined effect of enterocin A and thyme EOs against food pathogen bacteria. This combination could be useful in food bio-preservation. PMID:25829595

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

    2016-02-01

    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 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. PMID:26637600

  16. 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. PMID:26249573

  17. 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.

  18. 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.

  19. 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

    2015-01-01

    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. PMID:25558854

  20. 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.

  1. Relationship between complex compositions and their bactericidal activity in binary mixture of sodium 1-octanesulfonate and lanthanum (III) chloride; Okutansuruhon san natoriumu-enka rantan (III) kongo suiyoekichu ni keiseisareru fukugotai no sosei to sono sakkin sayo tono kanrensei

    Energy Technology Data Exchange (ETDEWEB)

    Kihara, K.; Furuta, T. [Saraya Co. Ltd., Osaka (Japan)

    1997-05-10

    The composition of complexes formed in aqueous solution consisting of a binary mixture of sodium 1-octanesulfonate (NaOS) and lanthanum (III) chloride (LaCl3) was studied by measuring surface tension, electric conductivity and proton spin-lattice relaxation time. In the molar ratio of octanesulfonic anion and lanthanum (III) cation below 0.1, a 3:1-complex was formed. The area per the 3:1-complex absorbed at air-water interface was 208 angstrom{sup 2} on the assumption of monomolecular layer. The formations of 2:1- and 1:1-complex were found in the vicinity of 0.5 and above 1.2 of LaCl3/NaOS, respectively. Whereas, when LaCl3 was added to 15 mol m{sup -3} NaOS, the bactericidal activity of the mixed solution against Escherichia coli ATCC 25922 markedly increased with increasing the molar ratio (LaCl3/NaOS) up to 1.0 and finally remained constant. The contribution of complexes on the bactericidal activity was estimated at 1.5:1:1 from the combination of data of complex distributions and bactericidal activity. 13 refs., 8 figs., 1 tab.

  2. Seroprevalence of bactericidal, specific IgG antibodies and incidence of meningitis due to group A Neisseria meningitidis by age in Burkina Faso 2008.

    Directory of Open Access Journals (Sweden)

    Caroline L Trotter

    Full Text Available BACKGROUND: We investigated serological correlates of protection against Neisseria meningitidis serogroup A (NmA in Burkina Faso before the introduction of NmA conjugate vaccine. METHODOLOGY/PRINCIPAL FINDINGS: We collected blood from a representative sample (N = 1022 of Bobo-Dioulasso residents. Sera were evaluated for serum bactericidal antibody (SBA activity against NmA strains of immunotype L11 (F8238 and L10 (3125 and NmA-specific IgG. Seroprevalence was compared to the age-specific NmA meningitis incidence in Bobo-Dioulasso during March 2007-February 2008. Meningococcal carriage was evaluated in a subset (N = 538. Geometric mean titres (GMT/concentrations (GMC of SBA and NmA-specific IgG increased with age, peaking around age 20 years. Overall, 70% of our sample had NmA-specific IgG ≥2 ug/mL. Meningitis incidence was highest in those aged <6 months and 5-19 years. No NmA carriers were found. Compared to the reference strain SBA, GMTs were higher against a locally isolated strain and around 40-fold lower against Dutch strain 3125. CONCLUSIONS/SIGNIFICANCE: This study provides estimates of natural immunity to NmA, according to a variety of antibody measures, which will be helpful in ascertaining antibody persistence after MenAfriVac™ introduction. Age-specific seroprevalence of reference strain SBA titres most likely reflects exposure to meningococci and consecutive reactive immunity. We could not define any serological correlate of protection.

  3. 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.

  4. 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.

  5. Vancomycin 24-Hour Area under the Curve/Minimum Bactericidal Concentration Ratio as a Novel Predictor of Mortality in Methicillin-Resistant Staphylococcus aureus Bacteremia.

    Science.gov (United States)

    Britt, Nicholas S; Patel, Nimish; Horvat, Rebecca T; Steed, Molly E

    2016-05-01

    While previous studies have examined the association between vancomycin (VAN) exposure and MIC with regard to outcomes in methicillin-resistant Staphylococcus aureus bacteremia (MRSA-B), none have explored if a relationship exists with the VAN minimum bactericidal concentration (MBC). The objective of this study was to evaluate the VAN 24-h area under the curve (AUC24)/MBC ratio as a pharmacodynamic predictor of mortality. This retrospective cohort study included patients treated with VAN for MRSA-B with the primary outcome of 30-day all-cause mortality. Data collected included patient demographics, comorbidities, antimicrobial treatment data, therapeutic drug levels, and laboratory and microbiological data. Vancomycin MICs and MBCs were determined by Etest (MIC only) and broth microdilution (BMD). The vancomycin AUC24 was determined by pharmacokinetic maximum a posteriori probability Bayesian (MAP-Bayesian) analysis. The most significant breakpoint for 30-day mortality was determined by classification and regression tree (CART) analysis. The association between pharmacodynamic parameters (VAN AUC24/MICBMD, VAN AUC24/MICEtest, and AUC24/MBCBMD) and mortality were determined by χ(2) and multivariable Poisson regression. Overall mortality in this cohort (n = 53) was 20.8% (n = 11/53), and all corresponding MRSA blood isolates were VAN susceptible (MIC range, 0.5 to 2 μg/ml; MIC50, 1 μg/ml; MIC90, 1 μg/ml). The CART-derived breakpoints for mortality were 176 (VAN AUC24/MBC) and 334 (VAN AUC24/MICBMD). In multivariable analysis, the association between a VAN AUC24/MBC of ≥176 and survival persisted, but VAN AUC24/MICBMD values (≥334 or ≥400) were not associated with improved mortality. In conclusion, VAN AUC24/MBC was a more important predictor of 30-day mortality than VAN AUC24/MIC for MRSA-B. PMID:26953202

  6. 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

  7. 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.

  8. 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.

  9. 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。

  10. Bactericidal Effect Test on Disinfectant Compound of benzalkonium Bromide-Allicin%苯扎溴铵—大蒜素复方消毒剂的杀菌效果试验

    Institute of Scientific and Technical Information of China (English)

    李孝文; 陈峰; 董伟; 王晶; 殷铭阳; 田世杰; 孙志良

    2011-01-01

    为了探明苯扎溴铵—大蒜素复方消毒剂的杀菌效果,根据兽用消毒剂鉴定技术规范的相关规定,用不同稀释倍数(500、1000、2000、4000倍)的该消毒剂在不同时间段(1、5、10、20 min)对5种细菌(金黄色葡萄球菌、大肠杆菌、多杀性巴氏杆菌、溶血性链球菌C型及蜡样芽孢杆菌)进行杀菌效果试验,同时以苯扎溴铵和大蒜油为对照试验组,观察和评价苯扎溴铵—大蒜素复方消毒剂的杀菌效果.结果表明在2000倍稀释的状态下该复方消毒剂对以上5种细菌表现出了完全的杀菌效果.因此,苯扎溴铵—大蒜素复方消毒剂在2000倍的稀释状态下能达到良好的杀菌效果,便于临床应用.%In order to proven the bactericidal effect of disinfectant compound of Benzalkonium bromide-Allicin,regulations of identification of technical specifications veterinary disinfectant were to be used. Five kinds of bacteria (Staphylococcus aureus, Escherichia coli ,Pasteurella multocida ,Streptococcus-C and Bacilluscereus) at different time periods (1.5,10,20 min)are test by the sterilization way in different dilutions (500,1000,2000,4000 times) of the disinfectant. At the same time benzalkonium bromide and garlic oil were used as the control test group. The bactericidal effect test of disinfectant compound of Benzalkonium bromide-Allicin was observed and evaluated. The results show that the disinfectant compound in 2000 dilution of the bactericidal effect achieved the standard. Therefore, the disinfectant compound in 2000 dilution can be up to good results,and can be used in clinical.

  11. 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.

  12. Bioactivity of Several Bactericides against Xanthomonas campestris pv.citri%几种杀菌剂对柑桔溃疡病的生物活性

    Institute of Scientific and Technical Information of China (English)

    孙惠敏; 李保同; 郭明程; 陈慈相; 谢金招; 刘德力

    2011-01-01

    为筛选防治柑桔溃疡病的有效药剂,按大田推荐使用浓度,用抑菌圈法测定17种非铜药剂和5种含铜药剂对柑桔溃疡病的毒力,并研究7种非铜药剂田间防治效果.结果表明,代森锰锌、福美双、福美双·溴菌腈、农用链霉素、金核霉素和琥胶肥酸铜·乙磷铝·硫酸锌抑菌作用最强,其次为福美双·福美锌、大蒜素、络氨铜·络氨锌和盐酸吗啉胍·乙酸铜,过氧乙酸、噻唑锌、春雷菌素、中生菌素、琥珀酸铜和噻菌铜有微弱的抑菌作用,百菌清、多菌灵、苯醚甲环唑、叶青双、复硝酚钠和井冈霉素无抑菌作用.大田试验结果表明,30%金核霉素WP 500 mg/L和72%农用链霉素WP 200 mg/L处理对柑桔溃病的防效分别为76.34%和74.94%,显著优于其它药剂处理;80%代森锰锌WP 2000 mg/L、50%福美双WP 400 mg/L和50%福美双·溴菌腈WP 500 mg/L处理对柑桔溃病的防效分别为70.36%、66.55%和69.37%,与对照含铜药剂20%噻菌铜SC 67 mg/L处理无显著差异;大蒜素和叶青双对柑桔溃病防效较差,6%大蒜素EC 120 mg/L和20%叶青双WP 400 mg/L处理对柑桔溃病的防效分别为41.84%和21.82%,显著低于对照含铜药剂20%噻菌铜SC 67 mg/L处理.%In order to screen effective bactericides against Xanthomonas camprestris pv. citri, the toxicity of 17 non - copper fungicides and 5 copper fungicides against the strain of X. campestris pv. citri in the greenhouse were determined by the method of inhibition zone, and the efficacy of 7 non - copper fungicides in the field was tested. The results showed that manzoceb, thiram, thiram -bromothalonil, agricultural streptomycin, aureonucleomycin and DT -fosetyl -aluminium -zinc suffate had the strongest inhibitory effect on the pathogen, thiram- ziram, allicin, cupric tetramminosuffate- zinc tetramminosuffate and moroxydine hydrochloride- cupric acetate had relatively strong inhibitory effect, peracetic acid, Zn thiazole, Kasugamycin, Zhong

  13. The HICN liquid bactericidal effect observed against Mycobacterium tuberculosis%HICN液对结核分枝杆菌杀菌效果观察

    Institute of Scientific and Technical Information of China (English)

    胡永林; 韦永慧

    2012-01-01

      目的:探究用HICN液对结核分枝杆菌的杀菌效果。方法:将罗氏培根基上生长的典型结核分枝杆菌菌落,制成约1个麦氏浊度浓度菌悬液,试验组用两倍菌悬液体积的HICN液分别处理结核分枝杆菌菌液5min、10min、15min、20min、25min、30min、35min、40min、45min、50min、55min、60min后,接种于罗氏(L-J)培养基斜面,对照组用生理盐水代替HICN液。一并放到37℃培养箱培养42d后观察生长情况,并取培养后的菌落涂片染色镜检。结果:对照组各培养管结核分枝杆菌生长良好,菜花状菌落典型,布满整个培养基,涂片抗酸染色镜检可见典型结核分枝杆菌形态;经HICN液分别处理5min、10min、15min、20min后观察组各管结核分枝杆菌均有不同程度生长,但生长情况依次呈递减趋势,涂片镜检可见结核分枝杆菌形态;经HICN液分别处理25min、30min、35min、40min、45min、50min、55min、60min后观察组各管无菌落生长。结论:两倍于菌悬液浓度的HICN液对结核分枝杆菌有杀菌作用,杀菌时间≥25分钟,因HICN液是较好的溶血剂,实验室可采用HICN液处理带血标本进行结核分枝杆菌的涂片检查。%  Objective To explore the use the HICN liquid bactericidal effect against Mycobacterium tuberculosis. Method The typical M. tuberculosis colonies grown on the foundation of Roche training, made about a Maxwel turbidity concentration of bacterial suspension, the test group with the the HICN solution twice the volume of bacterial suspension, respectively, deal with Mycobacterium tuberculosis bacteria 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min after inoculation Roche (L-J) medium slant in the control group with saline instead of HICN liquid. Together into the 37℃incubator 42d observe the growth of smear staining and cultured colonies. Results In the control group, each culture tube of

  14. 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

  15. PILOT SCALE PRODUCTION OF DISSYMMETRIC GEMINI QUATERNARY AMMONIUM SALT AND ITS BACTERICIDAL PERFORMANCE%非对称双子季铵盐杀菌剂的中试合成及杀菌效果

    Institute of Scientific and Technical Information of China (English)

    刘晓峰; 李友明; 万小芳

    2012-01-01

    为了解决长期使用1227季铵盐杀菌剂带来的微生物抗药性问题,以十二/十四烷基叔胺为原料,和环氧氯丙烷通过一步法工艺合成了一种非对称双子季铵盐,并成功进行了100 kg的中试生产,目的产品转化率高达95%.此外,通过异养菌和铁细菌静态杀菌实验研究该非对称双子季铵盐的杀菌性能.实验结果表明:在40 mg/L剂量,对异养菌的杀菌率在8h和16h分别为90.43%和80%以上;4h时对铁细菌的杀菌率高达96.79%,杀菌率在44 h内能维持在95%~100%之间,优于常用杀菌剂1227的杀菌效果.最后,在“三泥”回收装置的循环水系统中投加该杀菌剂的应用试验表明:虽然夏季循环水的高温使细菌更易繁殖,但非对称双子季铵盐依然能将异养菌控制在1 000个/mL以下,有效抑制细菌的生长,杀菌率达到95%.%The dissymmetric Gemini quaternary ammonium salt was synthesized by one-step process from 12/14 alkyl tertiary amine and epichlorohydrin. A pilot scale production of 100 kilogram was also succeeded with the product conversion of 95%. Besides, its bactericidal capability was studied according to the static sterilization experiment of heterotrophic bacteria and iron bacteria. The results showed that the sterilization rate of heterotrophic bacteria was 90. 43% in 8 hours and over 80% in 16 hours, respectively. To the iron bacteria, the sterilization rate was easily up to 96. 79% in 4 hours and was maintained between 95%- 100% within 44 hours. The bactericidal capability is superior to the conventional bactericide 1227. Finally, during the bactericide was added into the "three sludge" recycling water, the experimental results showed that this product could keep the quantities of heterotroph below 1 000 per mL although the higher temperature in summer is beneficial to reproduction of all kinds of bacterias, which could restrain the growth of bacteria effectively with the sterilizing rate up to 95%.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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。

  1. 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。

  2. In Vitro bactericidal experiment of an'erdian skin antiseptic on common drug resistant bacteria%安尔碘皮肤消毒剂对常见耐药细菌的体外杀菌试验

    Institute of Scientific and Technical Information of China (English)

    唐毅; 萧晨路; 李和姐; 倪语星

    2011-01-01

    目的 了解安尔碘皮肤消毒剂对临床耐药菌的最小杀菌浓度.方法 采用对倍稀释法,以安尔碘皮肤消毒剂不同浓度对耐甲氧西林金黄色葡萄球菌(MRSA)和泛耐药鲍氏不动杆菌作用不同时间,观察杀菌效果.结果 安尔碘皮肤消毒剂在有效碘含量为8.125μg/ml时,作用1 min后,可将检测的所有菌株全部杀灭.结论 安尔碘皮肤消毒剂为强而有效的杀菌剂.%OBJECTIVE To understand the minimum bactericidal concentration of An'erdian Skin Antiseptic to drug resistant strains in clinics.METHODS Different concentrations of An'erdian Skin Antiseptic were applied to MRSA and pan-drug resistant Acinetobacter baumannii suspension for periods of time, then the sterilization effects were observed.RESULTS All of the drug resistant strains were eradicated with the effective content of iodine was 8.125 μg/ml and was applied for 1 min.CONCLUSION An' erdian skin antiseptic is a kind of strong and effective disinfectant.

  3. Study on the effects of S2- ions on the capacities of corrosion inhibitor,scale inhibitor and bactericide commonly used in circulating water%S2-对循环水常用缓蚀、阻垢及杀菌剂相关性能的影响研究

    Institute of Scientific and Technical Information of China (English)

    王亭; 郦和生

    2012-01-01

    通过静态实验研究了S2-对循环水常用缓蚀、阻垢和杀菌剂性能的影响.结果表明:S2-可使常见缓蚀单剂的缓蚀性能明显降低,在S2-质量浓度低于1 mg/L时,投加100 mg/L复合缓蚀阻垢剂YSW105可使水体的腐蚀速度低于0.1 mm/a;S2-对水稳剂的阻碳酸钙垢和阻磷酸钙垢性能影响不大,常用共聚物难以在含S2-水体中稳定锌盐;S2-对常用杀菌剂的杀菌性能影响均较大,质量浓度为3 mg/L时即可使其基本丧失杀菌性能.%The effects of S2- on the corrosion inhibitor,scale inhibitor and bactericide commonly used in circulating water have been studied by static tests. The results show that S2- can obviously reduce the corrosion inhibiting capacity of common single-dosed corrosion inhibitor. Adding 100 mg/L of complex scale and corrosion inhibitor YSW105 could make the corrosion rate less than 0.1 mm/a,when S2- concentration is less than 1 mg/L. S2-has little influence on the capacities for CaCO3 scale inhibiting & Ca3 (PO4)2 scale inhibiting of water stablizers, but using copolymers frequently is difficult to stabilize zinc salts in water body that contains S2-. S2- has great effects on the bactericidal capacity for the commonly used bactericides. When S2- concentration comes to 3 mg/L,it can basically make the bactericides lose their bactericidal capacity.

  4. 17%EDTA与1%NaOCl组合用于根管超声冲洗抗菌效果的临床研究%Bactericidal effect of 17% EDTA combined with 1% NaOCl as irrigant of root canals

    Institute of Scientific and Technical Information of China (English)

    黄辉; 李慧; 张行炜; 刘漪; 张晓希; 范华南

    2009-01-01

    Objective To evaluate the bactericidal effect of 17% EDTA combined with 1% NaOCl in ultrasonic irrigation of root canal.Methods Totally 100 single-rooted teeth in 100 patients with chronic periapical periodontitis were divided into five groups randomly of 20 teeth each. All root canals were instrumented by hand with stainless steel endodontic instruments and irrigated by ultrasound with 2.5% NaOCl (group A),1% NaOCl (group B), 17% EDTA+1% NaOCl (group C), 17% EDTA (group D), and saline(group E). Totally 30 μl of liquid sample was obtained from each root canal and examined for anaerobic bacteria colony counting before and after root canal instrumentation.Results After root canal instrumentation, the number of anaerobic bacteria colony was significantly reduced in all 5 groups (P<0.01) . The colony number in group C was less than that in group B (P<0.05), and than that in group D and E (P<0.01), there was no difference between group A and group C (P>0.05).Conclusion Ultrasonic combined with 17% EDTA+1% NaOCl irrigation has better bactericidal effects of root canal irrigation.%目的 研究17%EDTA+1%NaOCl与超声波联合应用杀灭感染根管内厌氧菌的效果.方法 将100例慢性根尖周炎患者共100颗患牙随机分为A组(2.5%NaOCl)、B组(1%NaOCl)、C组(17%EDTA+1%NaOCl)、D组(17%EDTA)、E组(生理盐水)5组,每组各20颗患牙,采用手持器械预备根管后,分别采用2.5%NaOCl、1%NaOCl、17%EDTA+1%NaOCl、17%EDTA、生理盐水超声法冲洗根管,根管预备前后分别取样进行厌氧培养.结果 根管预备前后,五组根管内厌氧菌减少程度之间有显著性差异(P<0.01),其中C组(17%EDTA+1%NaOCl组)厌氧菌的减少程度明显大于B组(1%NaOCl组)(P<0.05),显著大于D组(17%EDTA组)和E组(生理盐水组)(P<0.01),与A组(2.5%NaOCl组)之间无显著性差异(P>0.05).结论 17%EDTA+1%NaOCl与超声波联合应用可有效杀灭根管内的厌氧菌,其抗

  5. 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.

  6. 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.

  7. Bactericidal activity of human granulysin expressed in macrophages against intracellular Mycobacterium tuberculosis%巨噬细胞内表达的人颗粒溶素对胞内结核分枝杆菌的杀菌活性

    Institute of Scientific and Technical Information of China (English)

    伊正君; 付玉荣; 李俊明; 杨春; 何永林; 李娜; 朱道银

    2009-01-01

    Objective To construct eukaryotic expression recombinant plasmid containing human granulysin(GLS) and investigate the effect of GLS expression in macrophage RAW264.7 cells on the bactericidal activity against intracellular Mycobacterium tuberculosis.Methods GLS gene was amplified by nested-polymerase chain reaction(PCR) from human cytotoxicity T lymphocyte(CTL) activated by allogenic antigen,and inserted into pBudCE4.1 vector to construct recombinant plasmid.Subsequently,the plasmid was transfccted into RAW264.7 cells which were infected with Mycobacterium tuberculosis H37Rv.The expression of GLS was detected by nested-PCR and immunocytochemistry method.The RAW264.7 cells were lysed after transfected for 96 h,then acidfast stained,cultivated and colony count were done to determine the intraeellular bactericidal activity of GLS.The data were analyzed by t or t' test.Results The pBudCE4.1/GLS eukaryotic expression recombinant plasmid was successfully constructed.The transcriptional and translational expressions of target gene GLS were detected in RAW264.7 cells which were infected with Mycobacterium tuberculosis H37Rv.The bacterial load in macrophages of phorbol myristate acetate(PMA)+pBudCE4.1/GLS group,PMA+pBudCEA.1 group and non-activated group were 1.44±1.25,3.16±0.20 and 3.59±0.21,respectively.The differences between groups were all significant (t=2.403,t=2.854,both P<0.05).Conclusion Eukaryotic expression recombinant plasmid carrying human GLS gene expressed in macrophages has strong bactericidal activity against intracellular mycobacteria,which provide information for the further study on therapeutic vaccine against Mycobacterium tuberculosis.%目的 构建携带人颗粒溶素(GLS)的真核表达质粒并探讨其表达后对巨噬细胞RAW264.7内结核分枝杆菌的杀菌能力.方法利用套式PCR从同种异型抗原激活的人CTL中扩增出GLS基因,并克隆入pBudCE4.1载体,构建重组质粒.将其转染至感染结核分枝杆菌H37Rv

  8. Deactivation efficiency of stabilized bactericidal emulsions.

    Science.gov (United States)

    Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2011-09-20

    Biocide emulsions stabilized with various stabilizing agents were prepared and characterized, and their efficiency in bacteria deactivation was evaluated. A number of stabilizing agents were tested for their stabilizing effect on emulsions of thiocyanomethylthiobenzothiazole (TCMTB) biocide. Two agents, the most successful in stabilizing the biocide, were chosen for further studies: high molecular weight polyethyleneimine (PEI) and an amphiphilic block copolymer of poly(caprolactone)-b-poly(acrylic acid) (PCL(33)-b-PAA(33)). The emulsion droplet sizes varied between 325 and 500 nm. Deactivation of bacteria was studied by exposing E. coli ATCC 11229 bacteria dispersions to emulsions stabilized by positively charged PEI or negatively charged PCL-b-PAA micelles and by measuring their absorbance; E. coli do not grow with time in the presence of biocide emulsions. PEI molecules alone act as biocide and deactivate the bacteria. PCL-b-PAA micelles as stabilizing agent do not affect the growth of the E. coli ; bacteria are deactivated by TCMTB released from the emulsion droplets. The kinetics of emulsion dissolution studies revealed for both stabilizing agents a decrease in droplet size with time while the emulsions were subjected to dialysis. The biocide was released from the emulsions within ∼250 min; the droplet shells consist mostly of PEI or PCL-b-PAA insoluble complexes with the biocide, which do not dissolve during dialysis. SEM images confirm the presence of residual crumbled shells with holes after 24 h of dialysis. PMID:21823610

  9. Cloning and characterization of two lipopolysaccharide-binding protein/bactericidal permeability-increasing protein (LBP/BPI) genes from the sea cucumber Apostichopus japonicus with diversified function in modulating ROS production.

    Science.gov (United States)

    Shao, Yina; Li, Chenghua; Che, Zhongjie; Zhang, Pengjuan; Zhang, Weiwei; Duan, Xuemei; Li, Ye

    2015-09-01

    Lipopolysaccharide-binding protein and bactericidal permeability-increasing protein (LBP/BPI) play crucial role in modulating cellular signals in response to Gram-negative bacteria infection. In the present study, two isoforms of LBP/BPI genes (designated as AjLBP/BPI1 and AjLBP/BPI2, respectively) were cloned from the sea cucumber Apostichopus japonicus by RACE approach. The full-length cDNAs of AjLBP/BPI1 and AjLBP/BPI2 were of 1479 and 1455 bp and encoded two secreted proteins of 492 and 484 amino acid residues, respectively. Signal peptide, two BPI/LBP/CETP and one central domain were totally conserved in the deduced amino acid of AjLBP/BPI1 and AjLBP/BPI2. Phylogentic analysis further supported that AjLBP/BPI1 and AjLBP/BPI2 belonged to new members of invertebrates LBP/BPI family. Spatial expression analysis revealed that both AjLBP/BPI1 and AjLBP/BPI2 were ubiquitously expressed in all examined tissues with the larger magnitude in AjLBP/BPI1. The Vibrio splenfidus challenge and LPS stimulation could significantly up-regulate the mRNA expression of both AjLBP/BPI1 and AjLBP/BPI2, with the increase of AjLBP/BPI2 expression occurred earlier than that of AjLBP/BPI1. More importantly, we found that LPS induced ROS production was markedly depressed after AjLBP/BPI1 knock-down, but there was no significant change by AjLBP/BPI2 silencing. Consistently, the expression level of unclassified AjToll, not AjTLR3, was tightly correlated with that of AjLBP/BPI1. Silencing the AjToll also depressed the ROS production in the cultured coelomocytes. All these results indicated that AjLBP/BPI1 and AjLBP/BPI2 probably played distinct roles in bacterial mediating immune response in sea cucumber, and AjLBP/BPI1 depressed coelomocytes ROS production via modulating AjToll cascade. PMID:25956196

  10. Sustained release of bactericidal concentrations of penicillin in the pleural space via an antibiotic-eluting pigtail catheter coated with electrospun nanofibers: results from in vivo and in vitro studies

    Directory of Open Access Journals (Sweden)

    Chao YK

    2015-05-01

    Full Text Available Yin-Kai Chao,1 Cheng-Hung Lee,2 Kuo-Sheng Liu,1 Yi-Chuan Wang,3 Chih-Wei Wang,4 Shih-Jung Liu3 1Department of Thoracic and Cardiovascular Surgery, Chang Gung Memorial Hospital-Linkou, College of Medicine, Chang Gung University, Taoyuan, Taiwan; 2Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital-Linkou, College of Medicine, Chang Gung University, Taoyuan, Taiwan; 3Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan; 4Department of Pathology, Chang Gung Memorial Hospital-Linkou, College of Medicine, Chang Gung University, Taoyuan, Taiwan Background: Inadequate intrapleural drug concentrations caused by poor penetration of systemic antibiotics into the pleural cavity is a major cause of treatment failure in empyema. Herein, we describe a novel antibiotic-eluting pigtail catheter coated with electrospun nanofibers used for the sustained release of bactericidal concentrations of penicillin in the pleural space.Methods: Electrospun nanofibers prepared using polylactide-polyglycolide copolymer and penicillin G sodium dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol were used to coat the surface of an Fr6 pigtail catheter. The in vitro patterns of drug release were tested by placing the catheter in phosphate-buffered saline. In vivo studies were performed using rabbits treated with penicillin either intrapleurally (Group 1, 20 mg delivered through the catheter or systemically (Group 2, intramuscular injection, 10 mg/kg. Penicillin concentrations in the serum and pleural fluid were then measured and compared.Results: In vitro studies revealed a burst release of penicillin (10% of the total dose occurring in the first 24 hours, followed by a sustained release in the subsequent 30 days. Intrapleural drug levels were significantly higher in Group 1 than in Group 2 (P<0.001. In the former, penicillin concentrations remained above the minimum inhibitory concentration breakpoint throughout the entire

  11. 爱尔碘皮肤消毒剂对生物膜阳性致病菌的体外杀菌试验%In vitro bactericidal experiment of ai'erdian skin antiseptic on positive pathogenic bacteria

    Institute of Scientific and Technical Information of China (English)

    王福兰

    2012-01-01

    目的 了解爱尔碘皮肤消毒剂对生物膜阳性致病菌的最小杀菌浓度.方法 将所有受试菌进行生物膜形成检测,再用对倍稀释法,以爱尔碘皮肤消毒剂不同浓度对生物膜阳性致病菌作用不同时间,观察杀菌效果.结果 金黄色葡萄球菌、大肠埃希菌和铜绿假单胞菌生物膜形成阳性率分别为54.3%、47.3%和57.0%;爱尔碘皮肤消毒剂在有效碘含量为9.203×10-4 mg/L时,作用1 min后,可将所有受试菌株全部杀灭.结论 爱尔碘皮肤消毒剂对生物膜阳性致病菌具有高效的杀菌性.%OBJECTIVE To study the minimum bactericidal concentration of ai erdian skin antiseptic on positive pathogenic bacteria. METHODS All the pathogenic bacteria producing biofilm were tested, then different concentrations of ai erdian skin antiseptic were applied to the biofilm-positive pathogens for difference period of time,the sterilization effects were observed. RESULTS The positive rates of the formation of biofilm of Staphylo-coccus aureus , Escherichia coli and Pseudomonasaeruginosa were 54. 3% , 47. 3% and 57. 0% ; All of the positive pathogenic bacteria were eradicated with the effective content of iodine of 9. 203 × 10-4 mg/L for lmin. CONCLUSION Ai erdian skin antiseptic is a kind of strong and effective disinfectant on biofilm positive pathogenic bacteria.

  12. 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。

  13. Studies of the bactericidal effects of a He-Ne laser combined with toluidine blue O%He-Ne激光联合甲苯胺蓝O对金黄色葡萄球菌和大肠埃希菌杀菌作用的体外研究

    Institute of Scientific and Technical Information of China (English)

    顾冠彬; 王蕾; 刘昌荣

    2009-01-01

    目的 研究光动力疗法(PDT)对体外培养金黄色葡萄球菌、大肠埃希菌及其生物膜的杀菌作用,并初步探讨PDT的作用机制.方法 采用甲苯胺蓝O(TBO)为光敏剂,He-Ne激光为照射光源,通过菌落计数来研究POT对体外培养细菌的杀菌作用与TBO浓度的关系,及PDT对生物膜中细菌的杀菌作用;采用荧光分光光度法测定细菌对TBO的吸收来初步探讨PDT的作用机制.结果 当激光照射剂量固定时,PDT对体外培养细菌的杀伤作用随光敏剂浓度的增加而增加,采用优化的光动力反应条件,可使PDT对两种实验菌的杀菌率达到90%以上,且尽管大肠埃希菌对TBO的吸收多于金黄色葡萄球菌,但PDT对金黄色葡萄球菌杀菌作用强于大肠埃希菌.PDT对两种试验菌成熟和未成熟的生物膜中细菌的杀菌率作用差异不大,为20%~30%.结论 He-Ne激光联合TBO对体外培养细菌具有较强的杀菌作用,对生物膜中的细菌有一定的杀菌作用,且金黄色葡萄球菌对光动力作用更敏感,而这种光动力作用与细菌对光敏剂的吸收无关.%Objective To investigate the effects of photodynamic therapy (PDT) on Staphylococcus aureus and Escherichia coli strains and their laboratory-developed biofilms in vetro and the basic mechanisms of its action.Metods The bacteria were irradiated with a He-Ne laser in the presence of toluidine blue O (TBO).The colony forming units (CFU) of each strain were countde before and after treatment,and the uptakd of TBO by the bacteria was determined using fluorospectrophotometry. Results With a constant light dose,the bactericidal effects of PDT against the two bacteria cultures increasde woth the concentration of TBO,with the strongest bactericidal effect after PDT treatment more than 90%.S.aureus seemed to be more sensitive to PDT than E.coli,though the amount of TBO absorbed by the E.coli cells was significantly larger.The effects of PDT on mature and immature biofilms

  14. 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.

  15. Effect of Four Kinds of Common Bactericides on the Growth of Nitrifying Bacteria in Aquacultural Water%4种常用杀菌消毒剂对养殖水体中硝化细菌生长的影响

    Institute of Scientific and Technical Information of China (English)

    朱国霞; 于刚; 白东清; 周文礼; 吴旋; 孙宝静

    2012-01-01

    [ Objective ] The research aimed to provide scientific basis for adjusting and improving the balance of aquaculture micro-ecosystem and the reasonable application of drugs. [ Method ] Using nitrifying bacteria isolated from aquaculture water as test materials, the effects of common bactericides ClO2, KMnO4, formaldehyde, the mixture of copper sulfate and ferrous sulfate by the ratio of 5: 2 on the growth of nitrif-ying bacteria under the laboratory conditions were studied by the ecotoxicology method . [ Result ] 0.1 mg/L ClO2 , 0.6 mg/L KMnO4 , 20 mg/L formaldehyde, 0. 7 mg/L mixture of copper sulfate and ferrous sulfate by the ratio of 5 : 2 had small effects on the growth of nitrifying bacteria and better control effects on aquatic pathogenic microorganism in water body. [ Conclusion ] In the aquiculture, suitable concentration of bactericides should be used to disinfect the water body.%[目的]为调节和改善养殖微生态环境平衡和合理用药提供科学依据.[方法]以分离自养殖水体的硝化细菌为试验材料,运用生态毒理学的方法,在实验室条件下研究常用杀菌剂二氧化氯、高锰酸钾、甲醛、硫酸铜与硫酸亚铁合剂对其生长的影响.[结果]0.1mg/L二氧化氯、0.6mg/L高锰酸钾、20mg/L甲醛、0.7mg/L硫酸铜与硫酸亚铁(5∶2)合剂对硝化细菌生长的影响较小,同时对水体中的病原微生物有较好的防治效果.[结论]在水产养殖中,应选用适宜浓度的杀菌剂对水体进行消毒.

  16. 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。

  17. 淋病奈瑟菌rmp基因缺失突变株的构建及其抗体杀菌作用研究%Construction of a recombinant Neisseria gonorrhoeae strain with rmp gene deletion and study on the bactericidal activities of its antibodies

    Institute of Scientific and Technical Information of China (English)

    李国才; 解如山; 冒艳丽; 刘双喜; 焦红梅; 陈红菊; 严华; 季明春

    2013-01-01

    Objective To study the role of the outer membrane protein Rmp of Neisseria gonor-rhoeae strain in immunosuppression and the strategy of eliminating it .Methods The rmp gene of Neisseria gonorrhoeae strain was amplified by PCR and inserted into pMD 19-T vector .The recombinant vector pMD 19△rmp∷Kan containing Kan and the 5′-and 3′-flanking regions of rmp (△rmp∷Kan) was constructed by replacing 200 nucleotide residues of pMD 19-rmp with kanamycin resistance gene Kan and transformed into Neisseria gonorrhoeae WHO-A strain.PCR and Western blot assay were used to screen and identify the re-combinant mutant strains that could not express Rmp .Mice were immunized with mutant strains and bacteri-cidal activities of the immune sera were detected by antibody-mediated complement-dependent cytotoxicity assay.Results The mutant strains that could not encode Rmp were successfully constructed .Antibodies in-duced by mutant strains showed stronger bactericidal activity against Neisseria gonorrhoeae in comparison with those induced by wild strains .Conclusion The recombinant Neisseria gonorrhoeae strain with rmp gene de-letion might eliminate the immunosuppressive effects of Rmp expressed in wild gonococcal strains , which provides a reference for further development of novel live attenuated whole-cell vaccines of Neisseria gonor-rhoeae.%  目的研究淋病奈瑟菌的外膜蛋白Rmp在免疫阻抑中的作用及其消除策略。方法PCR扩增淋病奈瑟菌rmp基因,将rmp中间200个核苷酸残基用卡那霉素抗性基因Kan取代,含rmp两侧侧翼区和Kan的DNA片段△rmp∷Kan转化淋病奈瑟菌 WHO-A菌株,PCR和Western blot 鉴定野生rmp被突变基因(△rmp∷Kan)取代并不能表达Rmp的突变株。突变株免疫小鼠,并用抗体介导的补体杀菌作用研究免疫血清的抗菌活性。结果构建了rmp基因缺失的淋病奈瑟菌突变株,突变株诱生的抗体具有更强的杀伤淋病奈瑟菌活性。结论淋

  18. Comparison of bactericidal and cytotoxic activities of trichogin analogs.

    Science.gov (United States)

    Tavano, Regina; Malachin, Giulia; De Zotti, Marta; Peggion, Cristina; Biondi, Barbara; Formaggio, Fernando; Papini, Emanuele

    2016-03-01

    Peptaibiotics are a group of membrane active peptides of fungal origin. They typically contain α-aminoisobutyric acid (Aib; 1-letter code, U) and other non-coded residues (Toniolo and Brückner, 2009; Neumann et al., 2015; Benedett et al., 1982) [1], [2], [3] stabilizing their helical structure. Peptaibols are peptaibiotics carrying a 1, 2-aminoalcohol at the C-terminus. When a fatty acid chain (of 8-10 carbon atoms) is present at their N-terminus, they are called lipopeptaibols (Toniolo et al., 2001; Degenkolb et al., 2003) [4], [5]. We found (Tavano et al., 2015) [6] that the lipopeptaibol trichogin displays no antibacterial effects up to 64 µM, against both Gram(-) and Gram(+) bacteria, but kills tumor and healthy human cells via a mechanism requiring both the C-terminal primary alcohol group and the N-terminal n-octanoyl moiety, with EC50s around 4-5 µM. However, the substitution of single Gly residues with Lys strongly improves anti-Gram(+) activity (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion et al., 2012) [6], [7], [8]. To further characterize the activity of trichogin analogs as antibiotics and cytotoxic agents, we here manipulated the peptide helix amphipathicity by means of two different substitutions: (i) Aib to Leu (De Zotti et al., 2012) [7] or (ii) multiple Gly to Lys changes (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion, Formaggio et al., 2012; De Zotti, Biondi, Peggion, De Poli et al., 2012) [6], [7], [8], [9]. The antibacterial activity against four commensal or opportunistic bacterial species and the cytotoxicity against a panel of 9 healthy and tumor-derived eukaryotic cell types (including erythrocytes) are reported as MIC and EC50 (MTS - [3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)]-2H-tetrazolium- reduction and LDH - lactate dehydrogenase - release assay). PMID:26862583

  19. Comparison of bactericidal and cytotoxic activities of trichogin analogs

    Directory of Open Access Journals (Sweden)

    Regina Tavano

    2016-03-01

    Full Text Available Peptaibiotics are a group of membrane active peptides of fungal origin. They typically contain α-aminoisobutyric acid (Aib; 1-letter code, U and other non-coded residues (Toniolo and Brückner, 2009; Neumann et al., 2015; Benedett et al., 1982 [1–3] stabilizing their helical structure. Peptaibols are peptaibiotics carrying a 1, 2-aminoalcohol at the C-terminus. When a fatty acid chain (of 8–10 carbon atoms is present at their N-terminus, they are called lipopeptaibols (Toniolo et al., 2001; Degenkolb et al., 2003 [4,5]. We found (Tavano et al., 2015 [6] that the lipopeptaibol trichogin displays no antibacterial effects up to 64 µM, against both Gram− and Gram+ bacteria, but kills tumor and healthy human cells via a mechanism requiring both the C-terminal primary alcohol group and the N-terminal n-octanoyl moiety, with EC50s around 4–5 µM. However, the substitution of single Gly residues with Lys strongly improves anti-Gram+ activity (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion et al., 2012 [6–8]. To further characterize the activity of trichogin analogs as antibiotics and cytotoxic agents, we here manipulated the peptide helix amphipathicity by means of two different substitutions: (i Aib to Leu (De Zotti et al., 2012 [7] or (ii multiple Gly to Lys changes (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion, Formaggio et al., 2012; De Zotti, Biondi, Peggion, De Poli et al., 2012 [6–9]. The antibacterial activity against four commensal or opportunistic bacterial species and the cytotoxicity against a panel of 9 healthy and tumor-derived eukaryotic cell types (including erythrocytes are reported as MIC and EC50 (MTS - [3-(4, 5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl]-2H-tetrazolium- reduction and LDH - lactate dehydrogenase - release assay.

  20. Bactericidal Effect of Solar Water Disinfection under Real Sunlight Conditions▿

    Science.gov (United States)

    Boyle, M.; Sichel, C.; Fernández-Ibáñez, P.; Arias-Quiroz, G. B.; Iriarte-Puña, M.; Mercado, A.; Ubomba-Jaswa, E.; McGuigan, K. G.

    2008-01-01

    Batch solar disinfection (SODIS) inactivation kinetics are reported for suspensions in water of Campylobacter jejuni, Yersinia enterocolitica, enteropathogenic Escherichia coli, Staphylococcus epidermidis, and endospores of Bacillus subtilis, exposed to strong natural sunlight in Spain and Bolivia. The exposure time required for complete inactivation (at least 4-log-unit reduction and below the limit of detection, 17 CFU/ml) under conditions of strong natural sunlight (maximum global irradiance, ∼1,050 W m−2 ± 10 W m−2) was as follows: C. jejuni, 20 min; S. epidermidis, 45 min; enteropathogenic E. coli, 90 min; Y. enterocolitica, 150 min. Following incomplete inactivation of B. subtilis endospores after the first day, reexposure of these samples on the following day found that 4% (standard error, 3%) of the endospores remained viable after a cumulative exposure time of 16 h of strong natural sunlight. SODIS is shown to be effective against the vegetative cells of a number of emerging waterborne pathogens; however, bacterial species which are spore forming may survive this intervention process. PMID:18359829

  1. 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.

  2. Bactericidal antibiotic-phytochemical combinations against methicillin resistant Staphylococcus aureus

    OpenAIRE

    Bhone Myint Kyaw; Shuchi arora; Chu Sing Lim

    2012-01-01

    Methicillin resistant Staphylococcus aureus (MRSA) infection is a global concern nowadays. Due to its multi-drug resistant nature, treatment with conventional antibiotics does not assure desired clinical outcomes. Therefore, there is a need to find new compounds and/or alternative methods to get arsenal against the pathogen. Combination therapies using conventional antibiotics and phytochemicals fulfill both requirements. In this study, the efficacy of different phytochemicals in combination ...

  3. Bactericidal antibiotic-phytochemical combinations against methicillin resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Bhone Myint Kyaw

    2012-09-01

    Full Text Available Methicillin resistant Staphylococcus aureus (MRSA infection is a global concern nowadays. Due to its multi-drug resistant nature, treatment with conventional antibiotics does not assure desired clinical outcomes. Therefore, there is a need to find new compounds and/or alternative methods to get arsenal against the pathogen. Combination therapies using conventional antibiotics and phytochemicals fulfill both requirements. In this study, the efficacy of different phytochemicals in combination with selected antibiotics was tested against 12 strains of S. aureus (ATCC MRSA 43300, ATCC methicillin sensitive S. aureus or MSSA 29213 and 10 MRSA clinical strains collected from National University Hospital, Singapore. Out of the six phytochemicals used, tannic acid was synergistic with fusidic acid, minocycline, cefotaxime and rifampicin against most of strains tested and additive with ofloxacin and vancomycin. Quercetin showed synergism with minocycline, fusidic acid and rifampicin against most of the strains. Gallic acid ethyl ester showed additivity against all strains in combination with all antibiotics under investigation except with vancomycin where it showed indifference effect. Eugenol, menthone and caffeic acid showed indifference results against all strains in combination with all antibiotics. Interestingly, no antagonism was observed within these interactions. Based on the fractional inhibitory concentration indices, synergistic pairs were further examined by time-kill assays to confirm the accuracy and killing rate of the combinations over time. The two methods concurred with each other with 92% accuracy and the combinatory pairs were effective throughout the 24 hours of assay. The study suggests a possible incorporation of effective phytochemicals in combination therapies for MRSA infections.

  4. 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.

  5. Micrococcin P1 - A bactericidal thiopeptide active against Mycobacterium tuberculosis.

    Science.gov (United States)

    Degiacomi, Giulia; Personne, Yoann; Mondésert, Guillaume; Ge, Xueliang; Mandava, Chandra Sekhar; Hartkoorn, Ruben C; Boldrin, Francesca; Goel, Pavitra; Peisker, Kristin; Benjak, Andrej; Barrio, Maria Belén; Ventura, Marcello; Brown, Amanda C; Leblanc, Véronique; Bauer, Armin; Sanyal, Suparna; Cole, Stewart T; Lagrange, Sophie; Parish, Tanya; Manganelli, Riccardo

    2016-09-01

    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 disagreeable. Therefore, new drugs with novel targets are urgently needed to control resistant Mycobacterium tuberculosis strains. In this manuscript we report the characterization of the thiopeptide micrococcin P1 as an anti-tubercular agent. Our biochemical experiments show that this antibiotic inhibits the elongation step of protein synthesis in mycobacteria. We have further identified micrococcin resistant mutations in the ribosomal protein L11 (RplK); the mutations were located in the proline loop at the N-terminus. Reintroduction of the mutations into a clean genetic background, confirmed that they conferred resistance, while introduction of the wild type RplK allele into resistant strains re-established sensitivity. We also identified a mutation in the 23S rRNA gene. These data, in good agreement with previous structural studies suggest that also in M. tuberculosis micrococcin P1 functions by binding to the cleft between the 23S rRNA and the L11 protein loop, thus interfering with the binding of elongation factors Tu and G (EF-Tu and EF-G) and inhibiting protein translocation. PMID:27553416

  6. 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.

  7. 养殖大菱鲆黑瘦症的病原菌鉴定及杀菌中草药筛选%Causative pathogen of dark-thin syndrome in cultured Scophthalmus maximus and Chinese herbal medicine screening for the bactericidal effect

    Institute of Scientific and Technical Information of China (English)

    王印庚; 任海; 张正; 王岚; 荣小军; 廖梅杰; 陈霞

    2012-01-01

    从患黑瘦症的大菱鲆幼体内分离得到一株优势菌株,人工感染实验证实其为大菱鲆致病菌,并经过生理生化及16S rDNA序列分析鉴定为灿烂弧菌Vibrio splendidus.组织病理学显示,病鱼的肝脏、肾脏、脾脏、肠道及脑均呈现不同程度的组织破坏.用煎煮法提取11种常用中草药成分,测定该致病菌对中草药的杀菌效果.实验表明,五倍子和白头翁的杀菌效果最好,黄柏、穿心莲次之,当归、党参、杜仲、秦皮、金银花、乳香和没药的杀菌效果最差.以五倍子、白头翁为主要成分的初步治疗试验证明,药浴和口服给药可有效治愈大菱鲆苗期的黑瘦症.%Dark-thin syndrome often occurred at stages of larval turbot Scophthalmus maximus, causing lower metamorphosis and more than 80% of mortality. One bacterial strain was isolated from the diseased larvae, and it was confirmed to be the pathogen causing the disease through artificial infection tests. The pathogenic bacterium was identified as Vibrio splen-didus by conventional physiological and biochemical tests as well as 16S rDNA sequence analysis. In addition, histopathological studies demonstrated that the bacterium could cause infectious changes in the liver, kidney, spleen, intestine and brain. The effective components of 11 Chinese herbs were extracted respectively by the methond of decoction, and they were tested for the susceptibility against V. splendidus. The results showed that Galla chinensis and Radix pulsatillae had the best inhibitory effect on the bacterium, with minimal bactericidal concentration (MBC) of 25mg/ml. MBC for both Phellodendronchinen.se and Herba andrographitis was 50mg/ml. While Chinese angelica , Radix codonopsisand , Eucommia bark , Codex fraxini , Flos Inicerae , Bosxvellia carterii and Commiphora molmol had the weakest inhibition effect with MBC more than l00mg/ml. The preliminary tests indicated that G. chinensis and R. pulsatillae were good

  8. 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

  9. 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。

  10. 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...

  11. 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 ...

  12. Bactericidal effect of lactoferrin and lactoferrin chimera against halophilic Vibrio parahaemolyticus

    NARCIS (Netherlands)

    N. Leon-Sicairos; A. Canizalez-Roman; M. de la Garza; M. Reyes-Lopez; J. Zazueta-Beltran; K. Nazmi; B. Gomez-Gil; J.G. Bolscher

    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

  13. 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

    Chronic Pseudomonas aeruginosa lung infection is the most severe complication in cystic fibrosis patients. It is characterised by antibiotic-tolerant biofilms in the endobronchial mucus with zones of oxygen (O2) depletion mainly due to polymorphonuclear leucocyte activity. Whilst the exact mechan...

  14. Potent bactericidal efficacy of copper oxide impregnated non-porous solid surfaces

    OpenAIRE

    Monk, Alastair B.; Kanmukhla, Vikram; Trinder, Ken; Borkow, Gadi

    2014-01-01

    Background The role of fomites and the environment in nosocomial infections is becoming widely recognized. In this paper we discuss the use of Cupron copper oxide impregnated non-porous solid surface in the hospital setting and present in vitro testing data via USA Environmental Protection Agency (EPA) approved testing protocols that demonstrate the efficacy of these products to assist in reduction in environmental contamination and potentially nosocomial infections. Results The two counterto...

  15. 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

  16. Flexible bactericidal graphene oxide-chitosan layers for stem cell proliferation

    Science.gov (United States)

    Mazaheri, M.; Akhavan, O.; Simchi, A.

    2014-05-01

    Graphene oxide (GO)-chitosan composite layers with stacked layer structures were synthesized using chemically exfoliated GO sheets (with lateral dimensions of ˜1 μm and thickness of ˜1 nm), and applied as antibacterial and flexible nanostructured templates for stem cell proliferation. By increasing the GO content from zero to 6 wt%, the strength and elastic modulus of the layers increased ˜80% and 45%, respectively. Similar to the chitosan layer, the GO-chitosan composite layers showed significant antibacterial activity (>77% inactivation after only 3 h) against Staphylococcus aureus bacteria. Surface density of the actin cytoskeleton fibers of human mesenchymal stem cells (hMSCs) cultured on the chitosan and GO(1.5 wt%)-chitosan composite layers was found nearly the same, while it significantly decreased by increasing the GO content to 3 and 6 wt%. Our results indicated that although a high concentration of GO in the chitosan layer (here, 6 wt%) could decelerate the proliferation of the hMSCs on the flexible layer, a low concentration of GO (i.e., 1.5 wt%) not only resulted in biocompatibility but also kept the mechanical flexibility of the self-sterilized layers for high proliferation of hMSCs.

  17. Flexible bactericidal graphene oxide–chitosan layers for stem cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Mazaheri, M. [Department of Materials Science and Engineering, Sharif University of Technology, PO Box 11365-9466, Tehran (Iran, Islamic Republic of); Akhavan, O., E-mail: oakhavan@sharif.edu [Department of Physics, Sharif University of Technology, PO Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, PO Box 14588-89694, Tehran (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, PO Box 11365-9466, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, PO Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2014-05-01

    Highlights: • Fabrication of flexible graphene oxide–chitosan nanocomposite layers was reported. • The flexibility of the chitosan layers were improved by adding graphene oxide sheets. • The nanocomposite layers with 1.5 wt% graphene oxide content showed yielded flexible and antibacterial surfaces for stem cell proliferation. - Abstract: Graphene oxide (GO)–chitosan composite layers with stacked layer structures were synthesized using chemically exfoliated GO sheets (with lateral dimensions of ∼1 μm and thickness of ∼1 nm), and applied as antibacterial and flexible nanostructured templates for stem cell proliferation. By increasing the GO content from zero to 6 wt%, the strength and elastic modulus of the layers increased ∼80% and 45%, respectively. Similar to the chitosan layer, the GO–chitosan composite layers showed significant antibacterial activity (>77% inactivation after only 3 h) against Staphylococcus aureus bacteria. Surface density of the actin cytoskeleton fibers of human mesenchymal stem cells (hMSCs) cultured on the chitosan and GO(1.5 wt%)–chitosan composite layers was found nearly the same, while it significantly decreased by increasing the GO content to 3 and 6 wt%. Our results indicated that although a high concentration of GO in the chitosan layer (here, 6 wt%) could decelerate the proliferation of the hMSCs on the flexible layer, a low concentration of GO (i.e., 1.5 wt%) not only resulted in biocompatibility but also kept the mechanical flexibility of the self-sterilized layers for high proliferation of hMSCs.

  18. 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.

  19. 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.

  20. Heteronanostructure of Ag particle on titanate nanowire membrane with enhanced photocatalytic properties and bactericidal activities

    Energy Technology Data Exchange (ETDEWEB)

    Shang Lu; Li Bingjie [Department of Physics, Center for Optoelectronics Materials and Devices, and Key Laboratory of ATMMT, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Dong Wenjun, E-mail: wenjundong@zstu.edu.cn [Department of Physics, Center for Optoelectronics Materials and Devices, and Key Laboratory of ATMMT, Zhejiang Sci-Tech University, Hangzhou 310018 (China); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Chen Benyong; Li Chaorong; Tang Weihua [Department of Physics, Center for Optoelectronics Materials and Devices, and Key Laboratory of ATMMT, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Wang Ge, E-mail: gewang@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wu Jian [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310029 (China); Ying Yibin, E-mail: ybying@zju.edu.cn [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310029 (China)

    2010-06-15

    A novel seed induced method has been developed for syntheses of Ag particles on titanate nanowires, and then the heteronanostructured Ag/titanate nanowires were assembled into porous, flexible membranes. These titanate nanowires were about several hundreds micrometers in length and about 80 nm in diameter. The size of the Ag particle can be tuned within 300-700 nm. The pore size and thickness of the heteronanostructured membrane were easily controlled. An Ag/titanate nanowire membrane reactor has been developed to study the photocatalytic degradation of methamidophos in aqueous solution, and 87.0% of the methamidophos can be degraded in a concurrent filtration and photocatalytic oxidation process. The antibacterial activity was also investigated on the heteronanostructured membrane with UVA light (365 nm) irradiation, and a 99.99% satisfactory antibacterial effect on Escherichia coli was achieved.

  1. Glucocorticoid-Augmented Efferocytosis Inhibits Pulmonary Pneumococcal Clearance in Mice by Reducing Alveolar Macrophage Bactericidal Function.

    Science.gov (United States)

    Stolberg, Valerie R; McCubbrey, Alexandra L; Freeman, Christine M; Brown, Jeanette P; Crudgington, Sean W; Taitano, Sophina H; Saxton, Bridget L; Mancuso, Peter; Curtis, Jeffrey L

    2015-07-01

    Inhaled corticosteroids (ICS) increase community-acquired pneumonia (CAP) incidence in patients with chronic obstructive pulmonary disease (COPD) by unknown mechanisms. Apoptosis is increased in the lungs of COPD patients. Uptake of apoptotic cells (ACs) ("efferocytosis") by alveolar macrophages (AMøs) reduces their ability to combat microbes, including Streptococcus pneumoniae, the most common cause of CAP in COPD patients. Having shown that ICS significantly increase AMø efferocytosis, we hypothesized that this process, termed glucocorticoid-augmented efferocytosis, might explain the association of CAP with ICS therapy in COPD. To test this hypothesis, we studied the effects of fluticasone, AC, or both on AMøs of C57BL/6 mice in vitro and in an established model of pneumococcal pneumonia. Fluticasone plus AC significantly reduced TLR4-stimulated AMø IL-12 production, relative to either treatment alone, and decreased TNF-α, CCL3, CCL5, and keratinocyte-derived chemoattractant/CXCL1, relative to AC. Mice treated with fluticasone plus AC before infection with viable pneumococci developed significantly more lung CFUs at 48 h. However, none of the pretreatments altered inflammatory cell recruitment to the lungs at 48 h postinfection, and fluticasone plus AC less markedly reduced in vitro mediator production to heat-killed pneumococci. Fluticasone plus AC significantly reduced in vitro AMø killing of pneumococci, relative to other conditions, in part by delaying phagolysosome acidification without affecting production of reactive oxygen or nitrogen species. These results support glucocorticoid-augmented efferocytosis as a potential explanation for the epidemiological association of ICS therapy of COPD patients with increased risk for CAP, and establish murine experimental models to dissect underlying molecular mechanisms. PMID:25987742

  2. 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

    2016-01-01

    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. PMID:26525786

  3. An alternative bactericidal mechanism of action for lantibiotic peptides that target lipid II.

    Science.gov (United States)

    Hasper, Hester E; Kramer, Naomi E; Smith, James L; Hillman, J D; Zachariah, Cherian; Kuipers, Oscar P; de Kruijff, Ben; Breukink, Eefjan

    2006-09-15

    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 able to span the lipid bilayer and cannot form pores, but somehow they maintain their antibacterial efficacy. We describe an alternative mechanism by which members of the lantibiotic family kill Gram-positive bacteria by removing lipid II from the cell division site (or septum) and thus block cell wall synthesis. PMID:16973881

  4. Roles of antibody and complement in the bactericidal activity of mouse peritoneal exudate neutrophils.

    OpenAIRE

    Hart, P. H.; Spencer, L. K.; Hill, N L; McDonald, P J; Finlay-Jones, J. J.

    1987-01-01

    The contributions of complement and antibody to phagocytosis and, as a separate process, intracellular killing of Proteus mirabilis, were investigated using mouse peritoneal exudate neutrophils. Phagocytosis of P. mirabilis was promoted by both immune mouse (IMS) and normal mouse (NMS) sera. Opsonization by IMS promoted significantly greater phagocytosis than did NMS, as did NMS compared with heated IMS (HIMS). The ability of NMS to opsonize P. mirabilis for both phagocytosis and phagocytic k...

  5. 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.

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

    OpenAIRE

    Goel, Vikas Kumar; Kapil, Arti

    2001-01-01

    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 ...

  7. 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

  8. 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

    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......; 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...

  9. Bactericidal activity of curcumin I is associated with damaging of bacterial membrane.

    Directory of Open Access Journals (Sweden)

    Poonam Tyagi

    Full Text Available Curcumin, an important constituent of turmeric, is known for various biological activities, primarily due to its antioxidant mechanism. The present study focused on the antibacterial activity of curcumin I, a significant component of commercial curcumin, against four genera of bacteria, including those that are Gram-positive (Staphylococcus aureus and Enterococcus faecalis and Gram-negative (Escherichia coli and Pseudomonas aeruginosa. These represent prominent human pathogens, particularly in hospital settings. Our study shows the strong antibacterial potential of curcumin I against all the tested bacteria from Gram-positive as well as Gram-negative groups. The integrity of the bacterial membrane was checked using two differential permeabilization indicating fluorescent probes, namely, propidium iodide and calcein. Both the membrane permeabilization assays confirmed membrane leakage in Gram-negative and Gram-positive bacteria on exposure to curcumin I. In addition, scanning electron microscopy and fluorescence microscopy were employed to confirm the membrane damages in bacterial cells on exposure to curcumin I. The present study confirms the broad-spectrum antibacterial nature of curcumin I, and its membrane damaging property. Findings from this study could provide impetus for further research on curcumin I regarding its antibiotic potential against rapidly emerging bacterial pathogens.

  10. Radioiodinated DPA-713 Imaging Correlates with Bactericidal Activity of Tuberculosis Treatments in Mice

    OpenAIRE

    Ordonez, Alvaro A.; Pokkali, Supriya; DeMarco, Vincent P.; Klunk, Mariah; Mease, Ronnie C.; Foss, Catherine A.; Pomper, Martin G.; Jain, Sanjay K.

    2014-01-01

    Current tools for monitoring response to tuberculosis treatments have several limitations. Noninvasive biomarkers could accelerate tuberculosis drug development and clinical studies, but to date little progress has been made in developing new imaging technologies for this application. In this study, we developed pulmonary single-photon emission computed tomography (SPECT) using radioiodinated DPA-713 to serially monitor the activity of tuberculosis treatments in live mice, which develop necro...

  11. 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.

  12. Dye adsorption and bactericidal properties of TiO2/chitosan coating layer.

    Science.gov (United States)

    Kamal, Tahseen; Anwar, Yasir; Khan, Sher Bahadar; Chani, Muhammad Tariq Saeed; Asiri, Abdullah M

    2016-09-01

    A new kind of titanium oxide dispersed in chitosan (TiO2/CS) nanocomposite adsorbent was prepared and adhered to high surface area substrate, cellulose microfibers mat (CMM). CS-CMM and TiO2/CS-CMM were used for the thymol violet (TV) dye removal from wastewater. Characterization of materials was carried out by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscopy. The adsorption properties of both the CS-CMM and TiO2/CS-CMM were investigated as a function of adsorbent dosage, solution pH, and contact time. It was revealed that the composites pretreated in the solution with higher pH value exhibited larger adsorption capacities. Kinetic studies showed that the composites could adsorb TV dye rapidly and reached the equilibrium in 90min. The adsorption process followed pseudo-second order kinetics and involved particle diffusion mechanism. The calculated maximum adsorption capacities of CS-CMM and TiO2/CS-CMM were 84.32 and 97.51mgg(-1), respectively. Compare to CS, the TiO2/CS nanocomposite coated CMM showed higher antibacterial characteristics as tested against Escherichia coli. PMID:27185126

  13. Bactericidal Effects of Charged Silver Nanoparticles in Methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Romero-Urbina, Dulce; Velazquez-Salazar, J. Jesus; Lara, Humberto H.; Arellano-Jimenez, Josefina; Larios, Eduardo; Yuan, Tony T.; Hwang, Yoon; Desilva, Mauris N.; Jose-Yacaman, Miguel

    2015-03-01

    The increased number of infections due to antibiotic-resistant bacteria is a major concern to society. The objective of this work is to determine the effect of positively charged AgNPs on methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus(MRSA) cell wall using advanced electron microscopy techniques. Positively charged AgNPs suspensions were synthesized via a microwave heating technique. The suspensions were then characterized by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) showing AgNPs size range from 5 to 30 nm. MSSA and MRSA were treated with positively charged AgNPs concentrations ranging from 0.06 mM to 31 mM. The MIC50 studies showed that viability of MSSA and MRSA could be reduced by 50% at a positively charged AgNPs concentration of 0.12 mM supported by Scanning-TEM (STEM) images demonstrating bacteria cell wall disruption leading to lysis after treatment with AgNPs. The results provide insights into one mechanism in which positively charged AgNPs are able to reduce the viability of MSSA and MRSA. This research is supported by National Institute on Minority Health and Health Disparities (G12MD007591) from NIH, NSF-PREM Grant No. DMR-0934218, The Welch Foundation and NAMRU-SA work number G1009.

  14. Bactericidal and Fungicidal Activity in the Gas Phase of Sodium Dichloroisocyanurate (NaDCC).

    Science.gov (United States)

    Proto, Antonio; Zarrella, Ilaria; Cucciniello, Raffaele; Pironti, Concetta; De Caro, Francesco; Motta, Oriana

    2016-08-01

    Sodium dichloroisocyanurate (NaDCC) is usually employed as a disinfectant for the treatment of water, environmental surfaces and medical equipment principally for its effectiveness as a microbicide agent. In this study, we explore the possibility of a new use for NaDCC by investigating the microbicidal activity of chlorine, which derives from the hydrolysis of NaDCC mediated by air humidity, and by testing its effect on the neutralization of microbes present in domestic waste. NaDCC was inserted in a plastic garbage can where LB agar plates, with different dilutions of a known title of four different microorganisms (Escherichia coli, Staphylococcus aureus, Debaryomyces hansenii and Aspergillus brasiliensis), were weakly inserted. The molecular chlorine (Cl2) levels present in the garbage can were quantified using an iodometric titration. The gas emitted in the garbage can presented a strong microbicide effect, inhibiting the proliferation of all four microorganisms and for four consecutive weeks, thus showing that NaDCC hydrolysis, mediated by air humidity, is able to ensure the decontamination of restricted environments, avoiding the proliferation of both Gram-positive and Gram-negative bacteria as well as fungi. PMID:27086304

  15. 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.

  16. 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.

  17. Bactericidal effectiveness of UV radiators, type DRT-400, in a broilerhouse

    International Nuclear Information System (INIS)

    Three UV radiators, type DRT-400, were used in a broilerhouse of BIOS type; 12 lamps in a set, type ZNUV, worked inside of the premises for 5, 8, 12, 16 and 20 min. It was found a high degree reduction of bacteria and fungi in the air, at 60.3 and 74.0% respectively, on the external surface of bedding at 40.3% and 72.2%, and in automatic watering troughs at 44.0 and 97.7% respectively. The degree of microorganisms reduction depended on the time exposition to UV, general air contamination, place of contamination, i.e. bedding or water in troughs. (author)

  18. 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. PMID:26616926

  19. Effect of dexamethasone on bactericidal activity of turkey monocytes and implications for food safety

    Science.gov (United States)

    Stress has been shown to affect the immune system of turkeys making them more susceptible to bacterial infections that may compromise food safety. Female turkeys are more resistant to stress-induced opportunistic bacterial infections than are male turkeys. In order to determine the mechanism of this...

  20. 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.

  1. 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.

  2. 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.

  3. Re-Examining the Role of Hydrogen Peroxide in Bacteriostatic and Bactericidal Activities of Honey

    OpenAIRE

    Brudzynski, Katrina; Abubaker, Kamal; St-Martin, Laurent; Castle, Alan

    2011-01-01

    The aim of this study was to critically analyze the effects of hydrogen peroxide on growth and survival of bacterial cells in order to prove or disprove its purported role as a main component responsible for the antibacterial activity of honey. Using the sensitive peroxide/peroxidase assay, broth microdilution assay and DNA degradation assays, the quantitative relationships between the content of H2O2 and honey’s antibacterial activity was established. The results showed that: (A) the average...

  4. 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...

  5. Heteronanostructure of Ag particle on titanate nanowire membrane with enhanced photocatalytic properties and bactericidal activities

    International Nuclear Information System (INIS)

    A novel seed induced method has been developed for syntheses of Ag particles on titanate nanowires, and then the heteronanostructured Ag/titanate nanowires were assembled into porous, flexible membranes. These titanate nanowires were about several hundreds micrometers in length and about 80 nm in diameter. The size of the Ag particle can be tuned within 300-700 nm. The pore size and thickness of the heteronanostructured membrane were easily controlled. An Ag/titanate nanowire membrane reactor has been developed to study the photocatalytic degradation of methamidophos in aqueous solution, and 87.0% of the methamidophos can be degraded in a concurrent filtration and photocatalytic oxidation process. The antibacterial activity was also investigated on the heteronanostructured membrane with UVA light (365 nm) irradiation, and a 99.99% satisfactory antibacterial effect on Escherichia coli was achieved.

  6. Flexible bactericidal graphene oxide–chitosan layers for stem cell proliferation

    International Nuclear Information System (INIS)

    Highlights: • Fabrication of flexible graphene oxide–chitosan nanocomposite layers was reported. • The flexibility of the chitosan layers were improved by adding graphene oxide sheets. • The nanocomposite layers with 1.5 wt% graphene oxide content showed yielded flexible and antibacterial surfaces for stem cell proliferation. - Abstract: Graphene oxide (GO)–chitosan composite layers with stacked layer structures were synthesized using chemically exfoliated GO sheets (with lateral dimensions of ∼1 μm and thickness of ∼1 nm), and applied as antibacterial and flexible nanostructured templates for stem cell proliferation. By increasing the GO content from zero to 6 wt%, the strength and elastic modulus of the layers increased ∼80% and 45%, respectively. Similar to the chitosan layer, the GO–chitosan composite layers showed significant antibacterial activity (>77% inactivation after only 3 h) against Staphylococcus aureus bacteria. Surface density of the actin cytoskeleton fibers of human mesenchymal stem cells (hMSCs) cultured on the chitosan and GO(1.5 wt%)–chitosan composite layers was found nearly the same, while it significantly decreased by increasing the GO content to 3 and 6 wt%. Our results indicated that although a high concentration of GO in the chitosan layer (here, 6 wt%) could decelerate the proliferation of the hMSCs on the flexible layer, a low concentration of GO (i.e., 1.5 wt%) not only resulted in biocompatibility but also kept the mechanical flexibility of the self-sterilized layers for high proliferation of hMSCs

  7. 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.

  8. Effectivity of bactericides for oil field waters and chemicals in the secondary and tertiary petroleum production

    Energy Technology Data Exchange (ETDEWEB)

    Naeveke, R.; Schwartz, W.

    1983-06-01

    Populations of microorganisms in the petroleum area (production plants, processing plants) have been analyzed more or less extensively with respect to their components (physiologically defined groups, taxa). The by far most of the microorganisms to be found in the produced reservoir waters and petroleum are not to be regarded as autochtone microorganisms of the petroleum reservoirs. Polymers used in the viscosity flooding (hydroxy ethyl cellulose, xanthane and polyacrylamide preparations) proved to be differently resistant toward microbial attack. Xanthanes were degraded more easily, polyacrylamide was resistant. Particularly accumulative cultures of desulfurizers have proved aggressive toward polymers under anaerobic conditions. The minimal inhibiting concentrations of 9 biocides proposed to protect the polymers in the viscosity flooding were determined by 18 of these desulfurizer accumulative cultures. The values were between 10 to about 1500 g/l.

  9. 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...

  10. 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.

  11. 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.

  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. 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.

  14. Influence of ethylenediamine-n,n’-disuccinic acid (EDDS) concentration on the bactericidal activity of fatty acids in vitro

    Science.gov (United States)

    The antibacterial activity of mixtures of ethylenediamine-N,N’-disuccinic acid (EDDS) and antibacterial fatty acids (FA) was examined using the agar diffusion assay. Solutions of caproic, caprylic, capric, and lauric acids dissolved in potassium hydroxide (KOH) were supplemented with 0, 5, or 10 mM ...

  15. 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.

  16. 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...

  17. 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

  18. 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.

  19. Research and Application of TCMTB on Paper Bactericide%TCMTB造纸杀菌剂的研究与应用

    Institute of Scientific and Technical Information of China (English)

    赵天翼; 黄奇然; 李少清; 杨伟和

    2011-01-01

    根据工业杀菌剂不同活性成分的物化特性进行复配研究,研制开发了具有高效、广谱的复合型TCMTB造纸杀菌剂,解决目前市场上大多杀菌剂活性成分单一、用量大、易产生抗药性等问题,从而有效地控制造纸过程的微生物问题,抑制腐浆的形成,保证纸机的正常生产,延长停机清洗周期.

  20. Bactericidal activity of ciprofloxacin against amikacin- and cefotaxime-resistant gram-negative bacilli and methicillin-resistant staphylococci.

    OpenAIRE

    Simberkoff, M S; Rahal, J J

    1986-01-01

    The MICs and MBCs of ciprofloxacin were determined for clinical isolates of antibiotic-resistant aerobic bacteria. Decreased susceptibility to ciprofloxacin of cefotaxime- and amikacin-resistant Serratia marcescens and amikacin-resistant Pseudomonas aeruginosa strains were noted. The data suggest that ciprofloxacin susceptibility should be carefully monitored in treating patients with hospital-acquired bacterial infections.

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

    OpenAIRE

    Goel Vikas; Kapil Arti

    2001-01-01

    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, e...

  2. 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...

  3. 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.

  4. 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. PMID:27394009

  5. 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.

  6. Investigation of Diospyros Kaki L.f husk extracts as corrosion inhibitors and bactericide in oil field

    OpenAIRE

    Zhang, Jie; Song, Yingpan; Su, Huijun; ZHANG Li; Chen, Gang; Zhao, Jingrui

    2013-01-01

    Background Hydrochloric acid is used in oil-well acidizing commonly for improving the crude oil production of the low-permeable reservoirs, while it is a great challenge for the metal instruments involved in the acidification. Developing natural products as oilfield chemicals is a straight way to find less expensive, green and eco-friendly materials. The great plant resources in Qin-ling and Ba-shan Mountain Area of Shannxi Province enable the investigating of new green oil field chemicals. D...

  7. Short-term bactericidal efficacy of lauric arginate against Listeria monocytogenes present on the surface of frankfurters.

    Science.gov (United States)

    Taormina, P J; Dorsa, W J

    2009-06-01

    The antimicrobial lauric arginate (LAE) alone or in combination with an antimicrobial liquid smoke extract was studied as a postlethality treatment against Listeria monocytogenes on vacuum-packaged frankfurters. Treatment with 2 ml of 5,000 ppm of LAE reduced L. monocytogenes from 7.13 to 5.82 log CFU per package on day 0, and treatment with 3 ml reduced populations from 7.22 to 5.79 log CFU per package on day 0. Treatment with LAE and smoke flavor did not result in significantly different populations of L. monocytogenes (P or = 1.68 log CFU per package, and many of the treatments caused a > 2-log reduction within 48 h. In this study, the shortterm efficacy of LAE against L. monocytogenes on vacuum-packaged frankfurters was demonstrated, providing support for use of this postlethality treatment on frankfurters and sausages for control of this pathogen. PMID:19610332

  8. Bactericidal effects of silver plus titanium dioxide-coated endotracheal tubes on Pseudomonas aeruginosa and Staphylococcus aureus

    OpenAIRE

    Tarquinio, Keiko

    2010-01-01

    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 Pe...

  9. Simultaneous pharmacodynamic analysis of the lag and bactericidal phases exhibited by beta-lactams against Escherichia coli.

    OpenAIRE

    Li, R C

    1996-01-01

    Antibiotic-bacterium interactions are complex in nature. In many cases, bacterial killing does not commence immediately after the addition of an antibiotic, and a lag period is observed. Antibiotic permeation and/or the intermediate steps that exist between antibiotic-receptor binding and expression of cell death are two major possible causes for such lag period. This study was primarily designed to determine the relationship, if any, between antibiotic concentrations and the lag periods by a...

  10. 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.

  11. [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.

  12. Ag loaded WO3 nanoplates for efficient photocatalytic degradation of sulfanilamide and their bactericidal effect under visible light irradiation.

    Science.gov (United States)

    Zhu, Wenyu; Liu, Jincheng; Yu, Shuyan; Zhou, Yan; Yan, Xiaoli

    2016-11-15

    Sulfonamides (SAs) are extensively used antibiotics and their residues in the water bodies propose potential threat to the public. In this study, degradation efficiency of sulfanilamide (SAM), which is the precursor of SAs, using WO3 nanoplates and their Ag heterogeneous as photocatalysts was investigated. WO3 nanoplates with uniform size were synthesized by a facile one step hydrothermal method. Different amount of Ag nanoparticles (Ag NPs) were loaded onto WO3 nanoplates using a photo-reduction method to generate WO3/Ag composites. The physio-chemical properties of synthesized nanomaterials were systematically characterized. Photodegradation of SAM by WO3 and WO3/Ag composites was conducted under visible light irradiation. The results show that WO3/Ag composites performed much better than pure WO3 where the highest removal rate was 96.2% in 5h. Ag as excellent antibacterial agent also endows certain antibacterial efficiency to WO3, and 100% removal efficiency against Escherichia Coli and Bacillus subtilis could be achieved in 2h under visible light irradiation for all three WO3/Ag composites synthesized. The improved performance in terms of SAM degradation and antibacterial activity of WO3/Ag can be attributed to the improved electron-hole pair separation rate where Ag NPs act as effective electron trapper during the photocatalytic process. PMID:27450332

  13. Extracellular synthesis of silver nanoparticles by novel Pseudomonas veronii AS41G inhabiting Annona squamosa L. and their bactericidal activity

    Science.gov (United States)

    Baker, Syed; Mohan Kumar, K.; Santosh, P.; Rakshith, D.; Satish, S.

    2015-02-01

    In present investigation extracellular synthesis of silver nanoparticles were synthesized using cell free supernatant of Pseudomonas veronii AS41G isolated from Annona squamosa L. The bacterium significantly reduced silver nitrate to generate silver nanoparticles which was characterized with hyphenated techniques. Synthesis of silver nanoparticles preliminary confirmed by UV-Visible spectrophotometry with the intense peak at 410 nm, Further FTIR analysis revealed the possible role of biomolecules in the supernatant responsible for mediating the nanoparticles formation. The XRD spectra exhibited the characteristic Bragg peaks of 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. TEM microgram showed polydispersity of nanoparticles with size ranging from 5 to 50 nm. Synthesized silver nanoparticles showed antibacterial activity against human and environmental pathogens including MRSA. The study enlightens the role of biosynthesized silver nanoparticles as an emerging alternative for drug resistant microorganisms. The obtained results are promising enough to pave the environmentally benign nanoparticle synthesis processes without use of any toxic chemicals and also envision the emerging role of endophytes towards synthesis of nanoparticles. With scanty reports available on P.veronii species, a new role has been reported in this study which will be very valuable for future researchers working on it.

  14. 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...

  15. 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

  16. 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

    , 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....... While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively). Particularly against Salmonella Typhimurium LT2, the combinatory effect...... of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained...

  17. 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

  18. 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.

  19. 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.

  20. Enhanced bactericidal effect of enterocin A in combination with thyme essential oils against L. monocytogenes and E. coli O157:H7

    OpenAIRE

    Ghrairi, Taoufik; Hani, Khaled

    2013-01-01

    The combined effects of enterocin A with Thymus vulgaris essential oils (EOs) against Listeria monocytogenes and Escherichia coli O157:H7 were investigated in vitro by enumeration of surviving populations of testing pathogens and minimal inhibitory concentration (MIC) determination. Enterocin A was purified to homogeneity by RP-HPLC from the culture fluid of Enterococcus strain and thyme EOs were extracted from local Thymus vulgaris plants. The major constituent of thyme EOs oils determined b...

  1. 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

  2. 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

  3. 皮革防霉剂的现状与发展%The Present Situation and Development of the Leather Bactericide

    Institute of Scientific and Technical Information of China (English)

    李志坚; 杨伟和; 邱芙坚

    2002-01-01

    杀菌防霉是皮革工业的一个必要环节。由于法规和环保的要求,选择一种高效低毒的防霉剂是非常重要的,寻求具有协同效果的杀菌剂配方,是目前国际上新型工业杀菌剂研究的主流方向。TCMTB具有可靠的广谱杀菌活性,毒性低,性价比高。TCMTB其无比的优越性取得了世界各国的认同,并在皮革市场上获得了成功的应用。

  4. 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

  5. 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.

  6. 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.

  7. Bactericidal effect of visible light in the presence of erythrosine on Porphyromonas gingivalis and Fusobacterium nucleatum compared with diode laser, an in vitro study

    OpenAIRE

    Habiboallah, Ghanbari; Mahdi, Zakeri; Mahbobeh, Naderi Nasab; Mina, Zareian Jahromi; Sina, Faghihi; Majid, Zakeri

    2014-01-01

    Objectives: Recently, photodynamic therapy (PDT) has been introduced as a new modality in oral bacterial decontamination. Besides, the ability of laser irradiation in the presence of photosensitizing agent to lethal effect on oral bacteria is well documented. Current research aims to evaluate the effect of photodynamic killing of visible blue light in the presence of plaque disclosing agent erythrosine as photosensitizer on Porphyromonas gingivalis associated with periodontal bone loss and Fu...

  8. Inhalable Particles for "Pincer Therapeutics" Targeting Nitazoxanide as Bactericidal and Host-Directed Agent to Macrophages in a Mouse Model of Tuberculosis.

    Science.gov (United States)

    Gupta, Anuradha; Meena, Jairam; Sharma, Deepak; Gupta, Pushpa; Gupta, Umesh Dutta; Kumar, Sadan; Sharma, Sharad; Panda, Amulya K; Misra, Amit

    2016-09-01

    Nitazoxanide (NTZ) has moderate mycobactericidal activity and is also an inducer of autophagy in mammalian cells. High-payload (40-50% w/w) inhalable particles containing NTZ alone or in combination with antituberculosis (TB) agents isoniazid (INH) and rifabutin (RFB) were prepared with high incorporation efficiency of 92%. In vitro drug release was corrected for drug degradation during the course of study and revealed first-order controlled release. Particles were efficiently taken up in vitro by macrophages and maintained intracellular drug concentrations at one order of magnitude higher than NTZ in solution for 6 h. Dose-dependent killing of Mtb and restoration of lung and spleen architecture were observed in experimentally infected mice treated with inhalations containing NTZ. Adjunct NTZ with INH and RFB cleared culturable bacteria from the lung and spleen and markedly healed tissue architecture. NTZ can be used in combination with INH-RFB to kill the pathogen and heal the host. PMID:27463245

  9. 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...

  10. 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.

  11. CoaTx-II, a new dimeric Lys49 phospholipase A2 from Crotalus oreganus abyssus snake venom with bactericidal potential: Insights into its structure and biological roles.

    Science.gov (United States)

    Almeida, J R; Lancellotti, M; Soares, A M; Calderon, L A; Ramírez, D; González, W; Marangoni, S; Da Silva, S L

    2016-09-15

    Snake venoms are rich and intriguing sources of biologically-active molecules that act on target cells, modulating a diversity of physiological functions and presenting promising pharmacological applications. Lys49 phospholipase A2 is one of the multifunctional proteins present in these complex secretions and, although catalytically inactive, has a variety of biological activities, including cytotoxic, antibacterial, inflammatory, antifungal activities. Herein, a Lys49 phospholipase A2, denominated CoaTx-II from Crotalus oreganus abyssus, was purified and structurally and pharmacologically characterized. CoaTx-II was isolated with a high degree of purity by a combination of two chromatographic steps; molecular exclusion and reversed-phase high performance liquid chromatography. This toxin is dimeric with a mass of 13868.2 Da (monomeric form), as determined by mass spectrometry. CoaTx-II is rich in Arg and Lys residues and displays high identity with other Lys49 PLA2 homologues, which have high isoelectric points. The structural model of dimeric CoaTx-II shows that the toxin is non-covalently stabilized. Despite its enzymatic inactivity, in vivo CoaTx-II caused local muscular damage, characterized by increased plasma creatine kinase and confirmed by histological alterations, in addition to an inflammatory activity, as demonstrated by mice paw edema induction and pro-inflammatory cytokine IL-6 elevation. CoaTx-II also presents antibacterial activity against gram negative (Pseudomonas aeruginosa 31NM, Escherichia coli ATCC 25922) and positive (Staphyloccocus aureus BEC9393 and Rib1) bacteria. Therefore, data show that this newly purified toxin plays a central role in mediating the degenerative events associated with envenomation, in addition to demonstrating antibacterial properties, with potential for use in the development of strategies for antivenom therapy and combating antibiotic-resistant bacteria. PMID:27530662

  12. 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。

  13. A thermostable Salmonella phage endolysin, Lys68, with broad bactericidal properties against gram-negative pathogens in presence of weak acids.

    Directory of Open Access Journals (Sweden)

    Hugo Oliveira

    Full Text Available 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. While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively. Particularly against Salmonella Typhimurium LT2, the combinatory effect of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the destabilization and major disruptions of the cell outer membrane integrity due to the acidity caused by the organic acids and a relatively high muralytic activity of Lys68 at low pH. Lys68 demonstrates good (thermostability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry.

  14. In掺杂纳米ZnO杀菌性能的研究%Studies on the bactericidal performance of indium doped nano-zinc oxide

    Institute of Scientific and Technical Information of China (English)

    赵艳凝; 滕洪辉; 常立民; 文福姬

    2008-01-01

    分别在自然光、紫外光的光照下,研究了纳米ZnO与In掺杂纳米ZnO对大肠杆菌的杀菌性能,并对其杀菌机理进行初步探讨.通过对比得出结论:在相同浓度与温度条件下,采用紫外光照射的杀菌效果均优于自然光下的杀菌效果;采用In掺杂纳米ZnO对大肠杆菌的杀菌率高于纳米ZnO的杀菌率.其机理足In掺杂量很低(0.5%)的情况下,导致了整个体系能带的窄化,从而提高了纳米ZnO的杀菌降解性能.

  15. Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H2O2 and HNO2

    Science.gov (United States)

    Lukes, P.; Dolezalova, E.; Sisrova, I.; Clupek, M.

    2014-02-01

    The formation of transient species (OH·, NO2·, NO radicals) and long-lived chemical products (O3, H2O2, NO_{3}^{-} , NO_{2}^{-} ) produced by a gas discharge plasma at the gas-liquid interface and directly in the liquid was measured in dependence on the gas atmosphere (20% oxygen mixtures with nitrogen or with argon) and pH of plasma-treated water (controlled by buffers at pH 3.3, 6.9 or 10.1). The aqueous-phase chemistry and specific contributions of these species to the chemical and biocidal effects of air discharge plasma in water were evaluated using phenol as a chemical probe and bacteria Escherichia coli. The nitrated and nitrosylated products of phenol (4-nitrophenol, 2-nitrophenol, 4-nitrocatechol, 4-nitrosophenol) in addition to the hydroxylated products (catechol, hydroquinone, 1,4-benzoquinone, hydroxy-1,4-benzoquinone) evidenced formation of NO2·, NO· and OH· radicals and NO+ ions directly by the air plasma at the gas-liquid interface and through post-discharge processes in plasma-activated water (PAW) mediated by peroxynitrite (ONOOH). Kinetic study of post-discharge evolution of H2O2 and NO_{2}^{-} in PAW has demonstrated excellent fit with the pseudo-second-order reaction between H2O2 and NO_{2}^{-} . The third-order rate constant k = 1.1 × 103 M-2 s-1 for the reaction NO_{2}^{-} +H_{2}O_{2}+H^{+}\\to ONOOH+H_{2}O was determined in PAW at pH 3.3 with the rate of ONOOH formation in the range 10-8-10-9 M s-1. Peroxynitrite chemistry was shown to significantly participate in the antibacterial properties of PAW. Ozone presence in PAW was proved indirectly by pH-dependent degradation of phenol and detection of cis,cis-muconic acid, but contribution of ozone to the inactivation of bacteria by the air plasma was negligible.

  16. 氮氟共掺杂二氧化钛薄膜的制备、表征及杀菌性能%Preparation, Characterization and Bactericidal Activity of N-F-codoped TiO2 Film

    Institute of Scientific and Technical Information of China (English)

    丁卉; 张诺; 戎非; 付德刚

    2011-01-01

    通过溶胶-凝胶法制备了氮氟共掺杂TiO2(N-F-TiO2)溶胶,并利用丝网印刷法在玻璃基底上制备了N-F-TiO2薄膜,通过XRD,XPS及漫反射对N-F-TiO2进行了表征.XRD分析表明制备出的N-F-TiO2以锐钛矿结晶为主;XPS谱显示N元素以N-Ti-O成键的形式掺杂在晶体中,F元素以表面吸附和晶格掺杂的形式存在;紫外-可见漫反射表明与TiO2相比,N-F-TiO2的吸收强度明显增强,光吸收起始位置有明显红移.利用大肠杆菌做为实验菌种,采用可见光与365nm紫外光分别作为激发光源,对其相对存活率及细胞膜损伤程度进行了研究.结果表明:N-F-TiO2薄膜具有较高的杀菌效率,光照60min时紫外光下大肠杆菌相对存活率降低到0,可见光下为10%;细胞损伤实验结果表明在紫外光作为光催化激发光源时,菌悬液中脂质过氧化物(MDA)含量最大值可以达到1.4 nmo1/mg干细胞重,可见光下可以达到0.9 nmo1/mg干细胞重.%N-F-codoped TiO2 semiconductor Sol (N-F-TiO2) was synthesized by Sol-Gel method, and N-F-TiO2 film was prepared on soda-lime glass using silk-screen printing. X-ray diffraction (XRD) of N-F-TiO2 exhibits significant diffraction peaks representing the characteristic of anatase phase and contain trace amount of brookite. X-ray photoelectron spectroscope (XPS) test indicates that N element exists with N-Ti-O bonding in the crystals, while F element exists as a dopant in the lattice of TiO2 or adsorbs on the surface of N-F-TiO2. Diffuse reflectance spectra (DRS) of N-F-TiO2 shows increased absorption in the range of 300-500 nm compared with that of undoped TiO2 film. Antibacterial abilities of N-F-TiO2 films under 60min UV and visible light irradiation are identified using E. coli. The prepared N-F-TiO2 films exhibit excellent antibacterial abilities as observed both in bacterial surviving test and cell membrane damaging test. After the irradiation of UV-A, the relative survival percentage of E.coli decreases to 0 and the maximum content of malonaldehyde (MDA) is 1.4 nmol/mg (cell dry weight). Under the visible light irradiation, relative survival percentage of E. coli decreases to 10% and the maximum content of malonaldehyde is 0.9 nmol/mg (cell dry weight).

  17. Sterilizing Mechanism and Capabilities for Bactericidal Ceramics of Nanocrystalline TiO2 Film%纳米TiO2杀菌陶瓷的杀菌机理与性能

    Institute of Scientific and Technical Information of China (English)

    雷阎盈; 余历军; 张秀成

    2004-01-01

    本文采用均相沉积法在陶瓷表面制得均匀透明的多孔纳米TiO2膜材料.对该半导体微粒膜的光催化原理、膜表面活性氧类的形成机理、TiO2微粒催化杀菌机理进行探讨;用GB15979-1995的方法对该膜材料的杀菌性能进行测试,表明材料杀菌范围广、速度快、杀菌率高,对金黄色葡萄球菌、白色念珠菌、大肠杆菌在30min内的杀菌率均达到90.00%以上;对乙肝病毒在20min内的杀灭率达到43.43%.

  18. 壳聚糖微粒固定化Nisin的制备及其杀菌效果研究%The Preparation of Chitosan Particles Immobilized Nisin and the Bactericidal Effect of Immobilized Nisin

    Institute of Scientific and Technical Information of China (English)

    郭辉; 孙琼; 吴宏君; 钱俊青

    2014-01-01

    为延长乳酸链球菌素(Nisin)的持续杀菌时间,以壳聚糖微粒为载体吸附固定化Nisin,考察固定化过程的各因素的影响以及吸附类型,并研究固定化Nisin相较于游离Nisin的杀菌效果.试验结果表明:采用质量浓度12 mg/mL、粒径(142.20±0.92) nm的壳聚糖微粒固定化Nisin,在同一条件下,固定化Nisin杀菌效果要优于游离Nisin,其中相比游离Nisin可提高近15%的杀菌率,持续杀菌时间可达8d,较游离Nisin的杀菌时间缩短3~5d.

  19. 二氧化氯在蒜粒保藏中的杀菌作用研究%Study on the Bactericidal Action of Chlorine Dioxide in Canning Garlic Granule

    Institute of Scientific and Technical Information of China (English)

    赵敏; 乔旭光

    2005-01-01

    本实验研究了二氧化氯在蒜粒保藏中的杀菌作用,结果表明:二氧化氯浓度达到40mg·kg-1以上时,其杀菌作用明显表现出来,60mg·kg-1可以抑制各种菌类的生长.并将其杀菌能力与山梨酸钾、苯甲酸钠等常用防腐剂的杀菌力作了比较,研究了二氧化氯浓度、烫漂温度以及添加山梨酸钾、柠檬酸和氯化钠对二氧化氯杀菌效果的影响.

  20. 酸性氧化电位水根管冲洗的抗菌效果%Study on the Bactericidal Effect of Root Canals Irrigated with Electrolyzed Oxidizing Water

    Institute of Scientific and Technical Information of China (English)

    刘国勤; 赵海军; 张庆福; 陈俊; 张新海; 刘筠; 陈铁楼

    2007-01-01

    目的:研究酸性氧化电位水超声冲洗杀灭感染根管内厌氧菌的效果及其作为根管超声冲洗液的可行性.方法:将90例慢性根尖周炎患者共90颗患牙随机分为3组,每组各30颗患牙,第1组手持器械结合机用根管锉进行根管预备,常规针管式双氧水与生理盐水交替冲洗,第2、第3组同第一组进行根管预备,分别以生理盐水、酸性氧化电位水作为冲洗液进行根管超声冲洗,根管预备前后分别根管内取样进行厌氧菌培养.结果:第2组厌氧菌减少程度明显大于第1组(P<O.05);第3组厌氧菌减少程度大于第2组(P<O.01)、显著大于第1组(P<O.001).结论:超声波在根管预备方面有一定的优势,酸性氧化电位水配合超声冲洗能有效杀灭感染根管内的厌氧菌,是一种理想的根管超声冲洗消毒液.

  1. Comparison of Triclocarban with Triclosan M W in bactericidal soap%康洁新与特可新在除菌皂中杀菌效果的比较

    Institute of Scientific and Technical Information of China (English)

    李晓敏

    2005-01-01

    康洁新和特可新是两种应用于除菌皂中的主要功效原料.根据其性能、价格,在它们的适宜加入范围内选择同样的功效原料成本,又采用传统生产工艺选择合适的加入方法,然后,用卫生部规定的中的方法对常见的3种菌进行除菌效果检测,结果表明,5 min内加入康洁新的样皂除对绿脓杆菌的杀灭效果为99.80%外,对其余菌种杀灭效果均为100%,其效果优于加入特可新的样皂.

  2. Toxicity Measurement of Several Bactericides on Erwinia carotovora susp. Atroseptica%几种杀细菌剂对胡萝卜软腐欧文氏菌的毒力测定

    Institute of Scientific and Technical Information of China (English)

    雷玉明; 张建朝; 邢会琴; 费永祥

    2010-01-01

    采用室内抑菌圈法测定了6种杀细菌剂对胡萝卜软腐欧文氏菌马铃薯黑胫病亚种(Erwinia carotovora susp. Atroseptica)的毒力,筛选出2种有明显抑菌作用的药剂72%农用硫酸链霉素可湿性粉剂和90%链霉素·土可溶性粉剂,抑菌效果显著,EC50分别为0.092 1 mg·mL-1和0.097 2 mg·mL-1.

  3. Characterization of Diverse Subvariants of the Meningococcal Factor H (fH) Binding Protein for Their Ability To Bind fH, To Mediate Serum Resistance, and To Induce Bactericidal Antibodies

    NARCIS (Netherlands)

    K.L. Seib; B. Brunelli; B. Brogioni; E. Palumbo; S. Bambini; A. Muzzi; F. Dimarcello; S. Marchi; A. van den Ende; B. Aricó; S. Savino; M. Scarselli; M. Comanducci; R. Rappuoli; M.M. Giuliani; M. Pizza

    2011-01-01

    Neisseria meningitidis is a commensal of the human nasopharynx but is also a major cause of septicemia and meningitis. The meningococcal factor H binding protein (fHbp) binds human factor H (fH), enabling down-regulation of complement activation on the bacterial surface. fHbp is a component of two s

  4. 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.

  5. The effect of polyhexamethylene guanidine hydrochloride (PHMG) derivatives introduced into polylactide (PLA) on the activity of bacterial enzymes

    OpenAIRE

    Walczak, Maciej; Richert, Agnieszka; Burkowska-But, Aleksandra

    2014-01-01

    The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect on Staphylococcus aureus than on E. coli but only PHMG granular polyethylene wax (at the concentration of at least 0.6 %) has a bactericidal effect....

  6. Decreased outer membrane permeability protects mycobacteria from killing by ubiquitin-derived peptides

    OpenAIRE

    Purdy, Georgiana E.; Niederweis, Michael; Russell, David G.

    2009-01-01

    Ubiquitin-derived peptides are bactericidal in vitro and contribute to the mycobactericidal activity of the lysosome. To further define interactions of ubiquitin-derived peptides with mycobacteria, we screened for mutants with increased resistance to the bactericidal activity of the synthetic ubiquitin-derived peptide Ub2. The four Ub2-resistant M. smegmatis mutants were also resistant to the bactericidal action of other antimicrobial peptides and macrophages. Two mutants were in the mspA gen...

  7. Biological Characteristics and Screening of Bactericides Against Bacterial Leaf Spot Pathogen on Processing Pepper%加工型辣椒细菌性叶斑病病原菌生物学特性及抑菌药剂筛选

    Institute of Scientific and Technical Information of China (English)

    管晶晶; 张春竹; 罗明; 李克梅; 盛强; 孙翔

    2014-01-01

    研究了新疆加工型辣椒细菌性斑点病病原菌Pseudomonas syringae pv .syringae 的部分生物学特征,并采用室内平板抑菌和盆栽试验对6种杀菌剂的防病效果进行了测定和筛选.结果表明,辣椒细菌性斑点病病原菌最适合生长的培养基为BPA培养基.25~30℃为适宜生长温度,最适温度为28℃.适宜在 pH6.5~8.0环境中生长,最适 pH 值为7.病原菌在1% NaCl浓度下生长良好,大于4% NaCl 生长受抑制.供试药剂的室内平板抑菌效果为:可杀得2000>乙酸铜>链霉素>志信101>红星-2氢氧化铜>志信2000,可杀得2000和乙酸铜的EC50值分别为5.954 mg/L和7.439 mg/L.盆栽试验结果显示,在发病前保护性喷施各药剂的防病效果(43.34%~80.84%)优于发病后治疗性施药(12.35%~49.54%),其中可杀得2000和红星-2氢氧化铜的防治效果较好.%The experiment studied the biological characteristics and evaluation the control effect of several kinds of fungicide against processing pepper bacterial spot disease of Xinjiang.The results showed that Pseudomonas syringae pv.syringae is most suitable for growing medium-BPA medium,growing range of temperature is 25-30 ℃,the optimum temperature was 28 ℃,which grows in pH range of 6.5 to 8.0,the optimal pH value of 7.The pathogen grows well under 1% NaCl,when more than 4% NaCl,its growth was inhibited.Invitro experiment showed that Kocide2000> Copper acetate>Streptomycin>Copper Hydrox-ide101>Cupic Hydroxide> Copper Hydroxide2000.Kocide 2000 and Copper acetate EC50 values were 5.954 mg/L and 7.439 mg/L,Greenhouse tests showed that the control effect of protective spraying (43.34%-80.84%)is better than the control effect of therapeutic spraying(12.35%-49.54%),of which Kocide2000 and Cupic Hydroxide have better control effect.

  8. 利奈唑胺对耐多药结核分枝杆菌及非结核分枝杆菌体外敏感性研究%In vitro bactericidal assay of linezolid on multidrug-resistant tuberculosis and nontuberculous mycobacteria

    Institute of Scientific and Technical Information of China (English)

    张晓飞; 张范华; 张艳; 刘伟; 张嵘

    2014-01-01

    Objective To investigate the mycobactericidal efficacy of linezolid on multidrugresistant tuberculosis (MDR-TB) and nontuberculous mycobacteria (NTM) in vitro.Methods Seven hundred and sixty-two Mycobacterium tuberculosis and 20 NTM isolates from Hangzhou were identified by using hsp65 gene sequencing from March to June,2013.Seventy MDR-TB isolates,which were screened by using proportion method,and twenty NTM isolates were tested the MIC to linezolid,and the differences of MICs to linezolid between MDR-TB and NTM werw analyzed in vitro.Results All 70 MDR-TB isolates were inhibited at concentrations of ≤ 1 mg/L by linezolid,MIC50 was 0.5 mg/L and MIC90 1 mg/L.Of all 8 isolates inhibited at concentration of 1 mg/L,there were 6 isolates resistant to isoniazid,rifampin,streptomycin and ethambutol,suggesting this resistance pattern may reduce sensitivity to linezolid.Among the NTM isolates,18 Mycobacterium intracellulare isolates,whose MICs to linezolid at 8-16 mg/L,were non-resistant isolates,while 2 Mycobacterium abscessus isolates displaying MICs > 32 mg/L,were resistant to linezolid.Conclusions Linezolid showed great activity to MDR-TB and there were no linezolid-resistant MDR-TB isolates identified in this study.However,MICs of MDR-TB against linezolid increased with their resistant numbers to first-line agents.This study also showed that different NTM species have varied sensitivity to linezolid.%目的 研究利奈唑胺对耐多药结核分枝杆菌(MDR-TB)和非结核分枝杆菌(NTM)的体外药物敏感性.方法 2013年3至6月使用hsp65基因测序比对的方法鉴定杭州地区762株结核分枝杆菌和20株NTM,通过比例法药敏试验获得70株MDR-TB,测定其与20株NTM对利奈唑胺的MIC,分析利奈唑胺对MDR-TB和NTM体外抑菌浓度的差异.结果 所测70株MDR-TB的利奈唑胺MIC均≤1 mg/L,MIC50为0.5 mg/L,MIC90为1 mg/L.对异烟肼、利福平、链霉素和乙胺丁醇耐药的MDR-TB菌株占MIC为1 mg/L菌株的6/8,提示其对利奈唑胺的敏感性有降低的趋势.NTM中18株胞内分枝杆菌对利奈唑胺MIC为8~ 16 mg/L,为非耐药株,2株脓肿分枝杆菌MIC均>32 mg/L,为耐药株.结论 利奈唑胺对MDR-TB具有很好的抗菌活性,本研究未发现其耐药株.MDR-TB对利奈唑胺的MIC随着其对一线药物耐药种类增多而升高.不同NTM种类的菌株对利奈唑胺具有不同的敏感性.

  9. 不同菠萝品种杀菌剂和褐变抑制剂对鲜切菠萝贮藏品质的影响%Effects of Pineapple Cultivator, Bactericide and Browning Inhibitors on Storage Quality of Fresh-cut Pineapple

    Institute of Scientific and Technical Information of China (English)

    窦同心; 孟祥春; 张爱玉; 张昭其

    2011-01-01

    研究了不同菠萝品种鲜切后冷藏的保鲜效果及不同杀菌剂和护色剂处理对鲜切菠萝保鲜效果的影响.结果表明,菠萝鲜切后在贮藏后期仍可保持较高的感官品质,并使果实保持一定的VC,TA,TSS含量.采用诺福水处理可明显抑制微生物的生长、保持鲜切菠萝的食用品质、延长货架期.采用质量分数为1%的抗坏血酸处理可显著地减缓果肉的褐变、色度L值和硬度的变化.

  10. 循环水排污水中杀菌剂、缓蚀阻垢剂对混凝效果的影响%Effects of Bactericides,Corrosion and Scale Inhibitors on Coagulation in Blow-down Water From Circulating Water System

    Institute of Scientific and Technical Information of China (English)

    杨伟; 刘芳; 樊丰涛; 张利

    2015-01-01

    When the blow‐down water from circulating water system is treated by coagulant‐sedimentation method ,the water treatment agents in it would have a certain effect on coagulation effect .For seeking influence of the agents on the coagulation process and its mechanism , the dosages of coagulant ,coagulant aid and operating conditions were optimized firstly ,and then the effects of single and compound water treatment agents on coagulation were investigated . In addition ,the effects of agents on optimum dosing amount of coagulant were investigated and flocculation obtained under different conditions was analyzed by SEM .The results showed that the optimized dosages of PAC and PAM were 40 mg/L and 0.8 mg/L ,respectively ,and the optimal operating conditions were fast stirring for 3 min at 300 r/min and slow stirring for 10 min at 90 r/min ,under which the coagulation effect of blow‐down water was best and turbidity removal rate reached 93.49% .Polyaspartic acid (PASP) had a greatest influence on coagulation of blow‐down water and residual turbidity raged from 0.85 to 1.78 nephelometric turbidity unit (NTU ) , w hile dodecyl dimethyl benzyl ammonium chloride (1227) had a greatest influence on the optimum amount of PAC ,which ranged from 20 to 70 mg/L .Residual turbidity was greater than 0.98 NTU at the existence of compound agents . According to SEM photos , the difference in microstructures of flocculation from blow‐down water at different coagulation conditions led to different coagulation effect .%混凝沉淀法处理循环水排污水时,由于排污水中残余药剂的影响,混凝往往达不到理想效果。为了寻求药剂对混凝过程及机理的影响,首先对混凝剂(PAC)、助凝剂(PAM )的投加量以及混凝条件进行优化,然后在优化的混凝条件下,考察单体药剂以及复配药剂对排污水混凝效果的影响,还考察了药剂对 PAC最佳投加量的影响,并采用扫描电镜观测不同条件下絮凝体的微观结构。结果表明,PAC 和 PAM 的最佳投加量分别为40 mg/L、0.8 mg/L ,最佳混凝条件为快速搅拌时间3 min、慢速搅拌速率90 r/min、快速搅拌速率300 r/min、慢速搅拌时间10 min;在此条件下,排污水浊度去除率可达93.49%。PASP对排污水混凝效果影响最大,且剩余浊度波动性大,波动范围0.85~1.78 NTU (Nephelometric Turbidity Unit);1227对 PAC最佳投加量影响最大,波动范围20~70 mg/L。排污水存在复配药剂时,其混凝后得剩余浊度都大于无药剂时的0.98 N T U。不同条件下的排污水混凝所得絮凝体结构存在明显的差异,从而导致了混凝效果的不同。

  11. In vitro bactericidal activity of equine platelet concentrates, platelet poor plasma, and plasma against methicillin-resistant Staphylococcus aureus Actividad bactericida in vitro de concentrados de plaquetas, plasma pobre en plaquetas y plasma de equinos contra Staphylococcus aureus resistente a la meticilina

    Directory of Open Access Journals (Sweden)

    ME Álvarez

    2011-01-01

    Full Text Available The aims of the study were 1 to evaluate the antibacterial effect of equine platelet concentrates (ePCs (either activated or not with calcium gluconate (CG against methicillin-resistant Staphylococcus aureus (MRSA, and 2 to compare their antibacterial effect with activated platelet poor plasma (PPP and plasma (P. Blood products were allotted in 4 groups (ePC, ePC/CG, PPP/CG, and P plus a positive control group (PCG and a negative control group, and mixed with MRSA and Mueller-Hinton broth. Samples were incubated during 1, 4, 8, 12, and 24 h, and colony-forming units were counted. The bacterial growth was significantly (P = 0.01 inhibited by the ePC, ePC/CG, PPP/CG and P in comparison with the PCG during the first 12 h. At 24h only a statistically significant (P = 0.01 antibacterial effect was noticed for the ePC, ePC/ CG and PPP/CG in comparison with the PCG and P. Equine PCs and PPP provided the best in vitro antibacterial effect against MRSA.Los objetivos del estudio fueron: 1 evaluar el efecto antibacteriano de concentrados de plaquetas equinas (ePC (activados o no con gluconato de calcio (CG frente a Staphylococcus aureus meticilino-resistente (MRSA y 2 comparar su efecto antibacteriano contra plasma pobre en plaquetas (PPP (activado con CG -PPP/GC- y plasma (P. Los productos sanguíneos fueron divididos en 4 grupos (ePC, ePC/CG, PPP/CG y P, más un grupo control positivo (PCG y otro control negativo. Los grupos se mezclaron con caldo Mueller-Hinton y MRSA. Las muestras fueron incubadas durante 1, 4, 8, 12 y 24 horas y se contaron las unidades formadoras de colonias. El crecimiento de las bacterias fue significativamente (P = 0,01 inhibido por el ePC, ePC/CG, PPP/CG y P en comparación con el PCG durante las primeras 12 h. Sólo a las 24 horas hubo una diferencia estadísticamente significativa (P = 0.01 y se observó un efecto antibacteriano para el ePC, ePC/CG y PPP/CG en comparación con el PCG y P. Los ePCs y PPP equinos mostraron el mejor efecto antibacteriano in vitro contra el MRSA.

  12. Tetrahydropyrazolo[1,5-a]pyrimidine-3-carboxamide and N-benzyl-6',7'-dihydrospiro[piperidine-4,4'-thieno[3,2-c]pyran] analogues with bactericidal efficacy against Mycobacterium tuberculosis targeting MmpL3.

    Directory of Open Access Journals (Sweden)

    Modesto J Remuiñán

    Full Text Available Mycobacterium tuberculosis is a major human pathogen and the causative agent for the pulmonary disease, tuberculosis (TB. Current treatment programs to combat TB are under threat due to the emergence of multi-drug and extensively-drug resistant TB. As part of our efforts towards the discovery of new anti-tubercular leads, a number of potent tetrahydropyrazolo[1,5-a]pyrimidine-3-carboxamide (THPP and N-benzyl-6',7'-dihydrospiro[piperidine-4,4'-thieno[3,2-c]pyran] (Spiro analogues were recently identified against Mycobacterium tuberculosis and Mycobacterium bovis BCG through a high-throughput whole-cell screening campaign. Herein, we describe the attractive in vitro and in vivo anti-tubercular profiles of both lead series. The generation of M. tuberculosis spontaneous mutants and subsequent whole genome sequencing of several resistant mutants identified single mutations in the essential mmpL3 gene. This 'genetic phenotype' was further confirmed by a 'chemical phenotype', whereby M. bovis BCG treated with both the THPP and Spiro series resulted in the accumulation of trehalose monomycolate. In vivo efficacy evaluation of two optimized THPP and Spiro leads showed how the compounds were able to reduce >2 logs bacterial cfu counts in the lungs of infected mice.

  13. 人杀菌通透性增强蛋白功能性N端片段在酵母细胞表面的展示和鉴定%Identification of N-terminal fragment of human bactericidal/permeability increasing protein displayed on the surface of yeast cells

    Institute of Scientific and Technical Information of China (English)

    李晶琴; 李慎涛; 温铭杰; 吕喆; 孙宝清; 许子华; 孔庆利; 安云庆

    2007-01-01

    目的:建立BPI23酵母细胞表面展示方法,使之表达具有生物活性的BPI23蛋白.方法:构建pYD1-BPI600重组质粒,转化酵母细胞,经半乳糖诱导使BPI23在酵母细胞表面表达;采用间接免疫荧光法,用荧光显微镜和流式细胞仪检测BPI23在酵母细胞表面的展示情况;采用鲎基质显色法,检测BPI23 中和内毒素的生物学活性.结果:酶切和DNA测序鉴定证实,pYD1-BPI600重组质粒含有人BPI600基因片段.荧光显微镜和流式细胞仪检测结果显示,BPI23在pYD1-BPI600重组质粒转化的酵母细胞表面得到展示;在诱导后第24小时展示BPI23的酵母细胞数占总细胞数的39%.酵母细胞表面展示的BPI23具有中和内毒素的活性.结论:成功构建了pYD1-BPI600酵母表达载体,转化后在酵母细胞表面展示了功能性目的蛋白,为BPI23突变体库的建立和功能优化BPI23突变体的筛选奠定了基础.

  14. 柠檬酸三钠与桂皮乙醇提取物对肠出血性大肠杆菌O157∶H7的协同杀菌效果%Synergistic bactericidal effect of cinnammon extract and sodium citrate on Escherichia coli O157∶H7

    Institute of Scientific and Technical Information of China (English)

    林琳; 赵呈婷; 周慧; 张雪婧; 蒲红顺; 崔海英

    2014-01-01

    本实验首先研究了桂皮挥发性物质中的主要成分桂皮醛对肠出血性大肠杆菌O157∶H7的杀菌效果.100ppm与200ppm的桂皮醛对肠出血性大肠杆菌O157∶H7显示了良好的杀菌效果.但是由于桂皮醛不能作为天然食品添加剂应用到食品中,因此我们探索了桂皮乙醇提取物对肠出血性大肠杆菌O157∶H7的抗菌效果.但是单独的桂皮乙醇提取物(0.5%)对肠出血性大肠杆菌O157∶H7的没有显示抗菌效果.因此,我们采用以柠檬酸三钠作为螯合剂,检测柠檬酸三钠与桂皮提取物对肠出血性大肠杆菌O157∶H7的协同杀菌效果.结果表明,柠檬酸三钠与桂皮提取物对肠出血性大肠杆菌O157∶H7显示了明显的协同效应,大大提高了桂皮乙醇提取物的杀菌活性.在含有0.5%的柠檬酸三钠与0.5%的桂皮提取物的生理盐水缓冲液在培养48h后,其菌数降低6个数量级,杀菌率达到了99.9999%.

  15. Atividade bacteriostática e bactericida do decocto de Baccharis trimera (Less.) D.C., Compositae, carqueja, como desinfetante ou anti-séptico Bacteriostatic and bactericidal activity of the Baccharis trimera (Less.) D.C. - Compositae decocto, as disinfectant or antisseptic

    OpenAIRE

    C.A.M. Avancini; J.M. Wiest; E. Mundstock

    2000-01-01

    Verificou-se a atividade antimicrobiana in vitro do decocto de Baccharis trimera (Less) D.C., Compositae, (carqueja) por meio de testes-padrão internacionais utilizados para avaliar desinfetantes e anti-sépticos. Determinaram-se a concentração inibitória mínima e a concentração bactericida mínima do decocto frente a várias diluições de inóculos. Os resultados sugerem a possibilidade de se utilizar o decocto de B. trimera como desinfetante e anti-séptico em determinadas situações-problema em p...

  16. 76 FR 45839 - Government-Owned Inventions; Availability for Licensing

    Science.gov (United States)

    2011-08-01

    ... antibodies would improve vaccine efficacy. This application claims Bordetella pertussis and Bordetella... Bordetella pertussis and bronchiseptica induce bactericidal antibodies, an addition to pertussis...

  17. How honey kills bacteria

    NARCIS (Netherlands)

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

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria t

  18. AcEST: DK949606 [AcEST

    Lifescience Database Archive (English)

    Full Text Available |GNL3_CAEEL Guanine nucleotide-binding protein-like 3 h... 37 0.099 sp|P17453|BPI_BOVIN Bactericidal permeability...RRKACNVGNLPGITKEIQ--EVELDKNIRLIDSPGVILVSQKDLD-PIEVALKNAIR 334 >sp|P17453|BPI_BOVIN Bactericidal permeability

  19. AcEST: DK959594 [AcEST

    Lifescience Database Archive (English)

    Full Text Available D1 OS=Ashbya gossypi... 31 4.9 sp|P17213|BPI_HUMAN Bactericidal permeability-increasing protein... 31 4.9 sp...|Q9Y3L3|3BP1_HUMAN SH3 domain-binding protein 1 OS=Homo sapien... 31 4.9 sp|P17453|BPI_BOVIN Bactericidal permeability...r|Q804Q9|Q804Q9_CYPCA Bactericidal permeability-increasing prot... 46 0.002 tr|Q6...protein OS=Xenopus laevis GN... 43 0.014 tr|Q4KTY6|Q4KTY6_ICTPU Bactericidal permeability-increasing prot......ive uncharacterized protein OS=Chaet... 38 0.46 tr|Q7T3Q9|Q7T3Q9_GADMO Bactericidal permeability increasing

  20. AcEST: DK961979 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ... 40 0.014 sp|P39712|FLO9_YEAST Flocculation protein FLO9 OS=Saccharomyces ... 34 0.59 sp|P17213|BPI_HUMAN Bactericidal permeabilit...y-increasing protein... 34 0.59 sp|Q8NFQ6|BPIL2_HUMAN Bactericidal/permeability-inc...reasing prote... 34 0.59 sp|P17453|BPI_BOVIN Bactericidal permeability-increasing...+SP + +S+ L Sbjct: 974 SSSSISSESPKSTYSSSSL 992 >sp|P17213|BPI_HUMAN Bactericidal permeability-increasing pro... >sp|Q8NFQ6|BPIL2_HUMAN Bactericidal/permeability-increasing protein-like 2 OS=Homo sapiens GN=BPIL2 PE=1 SV

  1. Structure of complexes of nitrilo tris methylene phosphonic acid with copper, [CuN(CH{sub 2}PO{sub 3}){sub 3}(H{sub 2}O){sub 3}] and Na{sub 4}[CuN(CH{sub 2}PO{sub 3}){sub 3}]{sub 2} · 19H{sub 2}O, as bactericides and inhibitors of scaling and corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Somov, N. V., E-mail: somov@phys.unn.ru [University of Nizhni Novgorod (Russian Federation); Chausov, F. F., E-mail: chaus@uni.udm.ru [Udmurt State University (Russian Federation)

    2015-03-15

    Nitrilotris methylene phosphonate triaqua copper and octasodium bis(nitrilotris methylene phosphonate cuprate(II)) nonadecahydrate have been synthesized and investigated. [CuN(CH{sub 2}PO{sub 3}){sub 3}(H{sub 2}O){sub 3}] is crystallized in the sp. gr. P2{sub 1}/c, Z = 4, a = 9.2506(2) Å, b = 15.9815(2) Å, c = 9.5474(2) Å, β = 113.697(2)°. The copper atom is coordinated by oxygen atoms in the configuration of elongated octahedron; the ligand (of bridge type) links neighboring copper atoms. Na{sub 8}[CuN(CH{sub 2}PO{sub 3}){sub 3}]{sub 2} · 19H{sub 2}O is crystallized in the sp. gr. P2{sub 1}/c, Z = 2, a = 11.24550(10) Å, b = 17.38980(10) Å, c = 13.5852(2) Å, β = 127.8120(10)°. This complex is chelating; the copper atom closes three five-membered N-C-P-O-Cu cycles with a shared Cu-N bond. Copper is coordinated in a distorted trigonal-bipyramidal configuration.

  2. Take Your Medicines Safely

    Medline Plus

    Full Text Available ... better, the antibiotic is working in killing the bacteria, but it might not completely give what they call a "bactericidal effect." That means taking the bacteria completely out of the system. It might be ...

  3. Take Your Medicines Safely

    Medline Plus

    Full Text Available ... the bacteria, but it might not completely give what they call a "bactericidal effect." That means taking ... be sure to ask the following six questions-- What is the name of the medicine? What is ...

  4. Potential antibiotic and anti-infective effects of rhodomyrtone from Rhodomyrtus tomentosa (Aiton) Hassk. on Streptococcus pyogenes as revealed by proteomics

    NARCIS (Netherlands)

    Limsuwan, Surasak; Voravuthikunchai, Supayang Piyawan; van Dijl, Jan Maarten; Kayser, Oliver; Meinders, Hesseling A.

    2011-01-01

    Rhodomyrtone from Rhodomyrtus tomentosa (Aiton) Hassk. leaf extract has a strong antibacterial activity against the bacterial pathogen Streptococcus pyogenes. Our previous studies indicated that the bactericidal activity of rhodomyrtone might involve intracellular targets. In the present studies we

  5. 50 CFR 260.99 - Buildings and structures.

    Science.gov (United States)

    2010-10-01

    ... suspended over exposed food in any step of preparation shall be of the safety type or otherwise protected to... openings. The use of chemical compounds such as cleaning agents, insecticides, bactericides, or...

  6. 40 CFR 180.1023 - Propanoic acid; exemptions from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ...) Propanoic acid is exempt from the requirement of a tolerance for residues in or on cattle, meat; cattle... byproducts; milk, and egg when applied as a bactericide/fungicide to livestock drinking water, poultry...

  7. Chemical composition of water extracts from shungite and shungite water

    International Nuclear Information System (INIS)

    Chemical analysis of water extracts from shungite-3 of Zagozhino deposit (Karelia) and natural water contacting with shungite rocks are done. Chemical composition and bactericide properties of shungite water are studied

  8. Arabidopsis CDS blastp result: AK103132 [KOME

    Lifescience Database Archive (English)

    Full Text Available similarity to SP|P17213 Bactericidal permeability-increasing protein precursor (BPI) {Homo sapiens}; contains Pfam profile PF02886: LBP / BPI / CETP family, C-terminal domain 1e-91 ...

  9. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice

    OpenAIRE

    SHI, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-01-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metab...

  10. Current and new strategies for the delivery of antiseptic agents.

    Science.gov (United States)

    Constant, Hélène; Falson, Françoise; Pirot, Fabrice

    2006-07-01

    The present mini-review explores the current methods used for the delivery of antiseptics and topical antimicrobials. Relevance of hand scrub with antiseptic liquid soap (e.g. chlorhexidine, PVP-iodine, triclosan) and alcohol-based hand rub is discussed and compared in terms of bactericidal activity, skin tolerance, and medical staff observance. New strategies for antibacterial delivery focus on the challenge of colloidal drug carrier such as liposomes, micro- and nanoparticles enabling sustained bactericidal effect and effective bacterial targeting.

  11. PA-824 Exhibits Time-Dependent Activity in a Murine Model of Tuberculosis▿

    OpenAIRE

    Ahmad, Zahoor; Peloquin, Charles A.; Singh, Rajendra P.; Derendorf, Hartmut; Tyagi, Sandeep; Ginsberg, Ann; Jacques H Grosset; Eric L Nuermberger

    2010-01-01

    PA-824 is one of two nitroimidazoles in phase II clinical trials to treat tuberculosis. In mice, it has dose-dependent early bactericidal and sterilizing activity. In humans with tuberculosis, PA-824 demonstrated early bactericidal activity (EBA) at doses ranging from 200 to 1,200 mg per day, but no dose-response effect was observed. To better understand the relationship between drug exposure and effect, we performed a dose fractionation study in mice. Dose-ranging pharmacokinetic data were u...

  12. Involvement of penicillin-binding protein 2 with other penicillin-binding proteins in lysis of Escherichia coli by some beta-lactam antibiotics alone and in synergistic lytic effect of amdinocillin (mecillinam).

    OpenAIRE

    Gutmann, L; Vincent, S; Billot-Klein, D; Acar, J F; Mrèna, E; Williamson, R.

    1986-01-01

    Compared with cefotaxime, ceftazidime, moxalactam, and aztreonam, ceftriaxone produced the best lytic and bactericidal effects when each was added at about 10 times the MIC to Escherichia coli W7. When each of these antibiotics was added at its MIC, only bacteriostasis occurred, but the simultaneous addition of amdinocillin (mecillinam) was synergistic in causing rapid lysis and bactericidal effects. Induction of lysis of two E. coli mutants containing either a thermosensitive penicillin-bind...

  13. Activities of new quinoline derivatives against genital pathogens.

    OpenAIRE

    AZNAR;, J.; Caballero, M C; Lozano, M C; Miguel, C. de; Palomares, J C; Perea, E J

    1985-01-01

    The in vitro activities of four quinoline carboxylic acids against 48 strains of Neisseria gonorrhoeae, 10 of Chlamydia trachomatis, and 32 of Ureaplasma urealyticum were compared. Ciprofloxacin was the most active against N. gonorrhoeae and C. trachomatis but had poor bactericidal activity against U. urealyticum, whereas ofloxacin showed the most bactericidal activity against U. urealyticum but was less active than ciprofloxacin against the two former pathogens. Norfloxacin and enoxacin were...

  14. Effects of Oakmoss and Its Components on Biofilm Formation of Legionella pneumophila

    OpenAIRE

    野村, 陽恵; 一色, 恭徳; Sakuda, Keisuke; 佐久間, 克也; 近藤, 誠一

    2013-01-01

    Oakmoss and its components are known as antibacterial agents, specifically against Legionella pneumophila. In the present study, we investigated the effects of oakmoss and its components (phenol, didepside and isochromen derivatives) on L. pneumophila biofilm formation, with particular reference to the bactericidal activity (minimum bactericidal concentration; MBC) of these components against the bacterial cells in the biofilm. Of the 20 compounds tested, two didepside derivatives and four ph...

  15. Influence of Physical and Chemical Modification on the Optical Rotatory Dispersion and Biological Activity of Chitosan Films

    Directory of Open Access Journals (Sweden)

    A. B. Shipovskaya

    2013-01-01

    Full Text Available The optical and bactericidal properties of acetic and basic chitosan films were studied. By the ORD technique, we found that these films differed in the values of their specific optical rotation and of their rotary and dispersive constants. A sign inversion of was observed when the acetic chitosan films were heat-treated. The bactericidal activity of the initial and dehydrated acetic films was analyzed, and their moisture content and optical and biological activities were compared.

  16. Activity of telavancin compared to other agents against coagulase-negative staphylococci with different resistotypes by time kill.

    Science.gov (United States)

    Lin, Gengrong; Pankuch, Glenn A; Appelbaum, Peter C; Kosowska-Shick, Klaudia

    2012-07-01

    Among 10 coagulase-negative staphylococci, telavancin, quinupristin/dalfopristin, and tigecycline were the most potent antimicrobials. Telavancin exhibited bactericidal effect to 9 strains out of 10 tested at 4× MIC after 24 h of exposure similar to those of vancomycin and daptomycin. By contrast, linezolid was mainly bacteriostatic and teicoplanin was bactericidal to 7 strains tested at 4× MIC after 24 h. PMID:22575272

  17. Evaluation of fusidic acid in therapy of experimental Staphylococcus aureus meningitis

    DEFF Research Database (Denmark)

    Østergaard, Christian; Yieng-Kow, Runa Vavia; Knudsen, Jenny Dahl;

    2003-01-01

    Combination therapy that includes fusidic acid, an antimicrobial agent highly active against staphylococci, has been recommended in the treatment of patients with Staphylococcus aureus meningitis. The aim of this study was to evaluate the pharmacokinetic, CSF bactericidal and anti-inflammatory pr......Combination therapy that includes fusidic acid, an antimicrobial agent highly active against staphylococci, has been recommended in the treatment of patients with Staphylococcus aureus meningitis. The aim of this study was to evaluate the pharmacokinetic, CSF bactericidal and anti...

  18. Salicylic acid and some of its derivatives as antibacterial agents for viscose fabric.

    Science.gov (United States)

    Kantouch, A; El-Sayed, A Atef; Salama, M; El-Kheir, A Abou; Mowafi, S

    2013-11-01

    Salicylic acid and three of its derivatives were used to provide antibacterial properties to viscose fabrics. The four bactericides used were bonded to the viscose fabrics using epichlorohydrin or polymer binders. Optimization of the salicylic acid and its derivatives as well as the concentration of polymers was reported. The ability of the polymer binders to attract and bind the four bactericides was observed. The overall results show that the antibacterial reactivity of salicylic acid and its derivatives are in the following order 5-bromosalicylic acid>salicylic acid>5-chlorosalicylic acid>4-chlorosalicylic acid. Using epichlorohydrin as a binding agent, unfortunately, inhibits the bactericidal activity of the four bactericides. The FTIR study concludes that the reaction between salicylic acid as well as its derivatives with epichlorohydrin takes place through the phenolic group of the acids. The unexpected deterioration in the bactericidal properties of salicylic acid and its derivatives as a result of the treatment with epichlorohydrin could be due to the nature of interaction between the epichlorohydrin molecule and the acids molecules. PVP and PU show superior ability to sustain the four bactericides used even after 10 washing cycles.

  19. Comparison of faecal and optimal growth conditions on in vitro pharmacodynamic activity of marbofloxacin against Escherichia coli.

    Science.gov (United States)

    Pellet, T; Gicquel-Bruneau, M; Sanders, P; Laurentie, M

    2006-06-01

    The objective of the study was to compare the in vitro activity of marbofloxacin against Escherichia coli (E. coli) strains with differing marbofloxacin susceptibility levels under optimal growth conditions and under condition mimicking faecal environment in time-kill kinetic studies. Under optimal growth conditions, marbofloxacin exerted a bactericidal concentration-dependent activity against all E. coli strains with bactericidal concentrations equal to 1 or 4 times MIC. Under faecal growth conditions, marbofloxacin maintained a bactericidal concentration-dependent activity but a 4- to 16-fold increase in bactericidal concentration was required to produce a similar magnitude of effect at 8 h. The bactericidal activity decreased between 8 and 24 h and allowed a residual bacterial population to subsist with a significant regrowth for some of them. Under no-growth conditions, marbofloxacin produced a very low decrease of non-dividing bacteria during a short time. No concentration produced a reduction > or = 3log10 in viable count excepted for two susceptible strains at concentration > or = 64 x MIC after 4 h exposure. The pharmacodynamic parameters from time-kill kinetic studies provide a useful means of studying antimicrobial activity. The importance of using different growth conditions is indicated by the difference in the killing of E. coli in the absence of active dividing cells and in the presence of autoclaved faecal content, both of which have a detrimental effect on the activity of marbofloxacin.

  20. Urease from Helicobacter pylori is inactivated by sulforaphane and other isothiocyanates.

    Science.gov (United States)

    Fahey, Jed W; Stephenson, Katherine K; Wade, Kristina L; Talalay, Paul

    2013-05-24

    Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 260-320 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections. PMID:23583386

  1. Inhibition of bacterial growth by different mixtures of propofol and thiopentone

    Directory of Open Access Journals (Sweden)

    K.E. Joubert

    2005-06-01

    Full Text Available Propofol is, as a result of its formulation, an ideal bacterial and yeast culture medium. An outbreak of sepsis in humans and an increase in wound infections in dogs has been ascribed to the use of propofol. It has been previously reported that a 1:1 mixture of propofol and thiopentone has bactericidal properties. This study was undertaken to determine if further serial mixtures of propofol and thiopentone maintained the bactericidal properties. Mixtures of 1:1 (solution A, 5:1 (solution B, 10:1 (solution C, 50:1 (solution D and 100:1 (solution E of 1 % propofol to 2.5 % thiopentone, 2.5 % thiopentone (solution T, 1 % propofol (solution P and saline (solution S were prepared and inoculated with between 105 and 106 colony-forming units of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. A sample was withdrawn from each solution at 0, 1, 6, 12, 48 and 120 hours after inoculation and a bacterial count was performed. This study showed that thiopentone and solution A behaved in similar fashion by inhibiting bacterial growth and was bactericidal after 48 hours. Solution B was not bactericidal against S. aureus and C. albicans. Propofol and solutions D and E all supported growth of all the organisms tested. These data indicate that mixtures of propofol and thiopentone at a ratio less than 1:1 do not maintain the bactericidal properties.

  2. Effects of granulocyte-colony stimulating factor on peritoneal defense mechanisms and bacterial translocation after administration of systemic chemotherapy in rats

    Institute of Scientific and Technical Information of China (English)

    Celal Cerci; Cagri Ergin; Erol Eroglu; Canan Agalar; Fatih Agalar; Sureyya Cerci; Mahmut Bulbul

    2007-01-01

    AIM: To investigate the effects of granulocyte-colony stimulating factor (G-CSF) on peritoneal defense mechanisms and bacterial translocation after systemic 5-Fluorouracil (5-FU) administration.METHODS: Thirty Wistar albino rats were divided into three groups; the control, 5-FU and 5-FU + G-CSF groups. We measured bactericidal activity of the peritoneal fluid, phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid, total peritoneal cell counts and cell types of peritoneal washing fluid.Bacterial translocation was quantified by mesenteric lymph node, liver and spleen tissue cultures.RESULTS: Systemic 5-FU reduced total peritoneal cell counts, neutrophils and macrophage numbers. It also altered bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. 5-FU also caused significant increase in frequencies of bacterial translocation at the liver and mesenteric lymph nodes. G-CSF decreased bacterial translocation, it significantly enhanced bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. It also increased total peritoneal cell counts, neutrophils and macrophage numbers.CONCLUSION: Systemic 5-FU administration caused bacterial translocation, decreased the bactericidal activity of peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. G-CSF increased both bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid, and prevented the bacterial translocation. We conclude that intraperitoneal GCSF administration protects the effects of systemic 5-FU on peritoneal defense mechanisms.

  3. Effects of oakmoss and its components on biofilm formation of Legionella pneumophila.

    Science.gov (United States)

    Nomura, Harue; Isshiki, Yasunori; Sakuda, Keisuke; Sakuma, Katsuya; Kondo, Seiichi

    2013-01-01

    Oakmoss and its components are known as antibacterial agents, specifically against Legionella pneumophila. In the present study, we investigated the effects of oakmoss and its components (phenol, didepside and isochromen derivatives) on L. pneumophila biofilm formation, with particular reference to the bactericidal activity (minimum bactericidal concentration; MBC) of these components against the bacterial cells in the biofilm. Of the 20 compounds tested, two didepside derivatives and four phenol derivatives reduced biofilm formation by more than 50% of that observed for the control at their respective minimum inhibitory concentrations (1/2×MIC). The inhibitory activities of these compounds were either equivalent to or greater than that of the clarithromycin reference. Isochromen derivatives had no effect on biofilm formation. Analysis of bactericidal activity of didepside and isochromen derivatives revealed that three of four didepside derivatives and one of four isochromen derivatives exhibited high bactericidal activity (MBC: 32.0-74.7 µg/mL) against the L. pneumophila in the biofilm after 24 h or 48 h of co-incubation; the antibacterial activities of these compounds were almost equivalent to clarithromycin and chlorhexidine gluconate (MBC: 42.7-64.0 µg/mL) that were used as references. Thus, based on their anti-biofilm forming and bactericidal activities, didepside derivatives are considered to be good candidates for disinfectants against L. pneumophila. PMID:23649339

  4. Importance of (antibody-dependent) complement-mediated serum killing in protection against Bordetella pertussis.

    Science.gov (United States)

    Geurtsen, Jeroen; Fae, Kellen C; van den Dobbelsteen, Germie P J M

    2014-10-01

    Pertussis is a highly contagious respiratory disease that is caused by Bordetella pertussis. Despite being vaccine preventable, pertussis rates have been rising steadily over the last decades, even in areas with high vaccine uptake. Recently, experiments with infant baboons indicated that although vaccination with acellular pertussis vaccines prevented disease, no apparent effect was observed on infection and transmission. One explanation may be that current acellular pertussis vaccines do not induce high levels of opsonophagocytic and/or bactericidal activity, implying that engineering of vaccines that promote bacterial killing may improve efficacy. Here, we discuss the importance of complement-mediated killing in vaccine-induced protection against B. pertussis. We first examine how B. pertussis may have evolved different complement evasion strategies. Second, we explore the benefits of opsonophagocytic and/or bactericidal killing in vaccine-induced protection and discuss whether or not inclusion of new opsonophagocytic or bactericidal target antigens in pertussis vaccines may benefit efficacy.

  5. Availability of the basal planes of graphene oxide determines whether it is antibacterial.

    Science.gov (United States)

    Hui, Liwei; Piao, Ji-Gang; Auletta, Jeffrey; Hu, Kan; Zhu, Yanwu; Meyer, Tara; Liu, Haitao; Yang, Lihua

    2014-08-13

    There are significant controversies on the antibacterial properties of graphene oxide (GO): GO was reported to be bactericidal in saline, whereas its activity in nutrient broth was controversial. To unveil the mechanisms underlying these contradictions, we performed antibacterial assays under comparable conditions. In saline, bare GO sheets were intrinsically bactericidal, yielding a bacterial survival percentage of planes. Using bovine serum albumin and tryptophan as well-defined model adsorbates, we found that noncovalent adsorption on GO basal planes may account for the deactivation of GO's bactericidal activity. Moreover, this deactivation mechanism was shown to be extrapolatable to GO's cytotoxicity against mammalian cells. Taken together, our observations suggest that bare GO intrinsically kills both bacteria and mammalian cells and noncovalent adsorption on its basal planes may be a global deactivation mechanism for GO's cytotoxicity.

  6. Tea polyphenol epigallocatechin gallate inhibits Escherichia coli by increasing endogenous oxidative stress.

    Science.gov (United States)

    Xiong, Li-Gui; Chen, Yi-Jun; Tong, Jie-Wen; Huang, Jian-An; Li, Juan; Gong, Yu-Shun; Liu, Zhong-Hua

    2017-02-15

    The antibacterial effects of tea polyphenol epigallocatechin gallate (EGCG), a common phytochemical with a number of potential health benefits, are well known. However, the mechanism of its bactericidal action remains unclear. Using E. coli as a model organism, it is argued here that H2O2 synthesis by EGCG is not attributed to its inhibitory effects. In contrast, the bactericidal action of EGCG was a result of increased intracellular reactive oxygen species and blunted adaptive oxidative stress response in E. coli due to the co-administration of antioxidant N-acetylcysteine, and not on account of exogenous catalase. Furthermore, we noted a synergistic bactericidal effect for EGCG when combined with paraquat. However, under anaerobic conditions, the inhibitory effect of EGCG was prevented. In conclusion, EGCG caused an increase in endogenous oxidative stress in E. coli, thereby inhibiting its growth, and hence the use of EGCG as a prooxidant is supported by this study.

  7. Antimicrobial Activity of Ceftriaxone Compared with Cefotaxime in the Presence of Serum Albumin

    Directory of Open Access Journals (Sweden)

    Swapan K Nath

    1995-01-01

    Full Text Available The effect of serum albumin on the antimicrobial activity of ceftriaxone, cefotaxime, and a 1:1 ratio of cefotaxime and its desacetyl metabolite against nonpseudomonal Gram-negative bacilli was determined. Antimicrobial activity of drugs was evaluated by measuring minimum inhibitory (mic and bactericidal (mbc concentrations in broth with and without human serum albumin. The analysis of logarithmically transformed mean mics and mbcs showed that there was a highly significant interaction between drug and serum albumin (P<0.0001. The inhibitory and bactericidal activities were greatest for cefotaxime followed by cefotaxime/desacetylcefotaxime and ceftriaxone (P<0.01. Time-kill kinetics demonstrated that ceftriaxone was less bactericidal than cefotaxime in broth with albumin. On the basis of these results it was concluded that the in vitro antimicrobial activity of ceftriaxone compared with that of cefotaxime was significantly diminished in the presence of serum albumin.

  8. The effect of polyhexamethylene guanidine hydrochloride (PHMG) derivatives introduced into polylactide (PLA) on the activity of bacterial enzymes.

    Science.gov (United States)

    Walczak, Maciej; Richert, Agnieszka; Burkowska-But, Aleksandra

    2014-11-01

    The present study was aimed at investigating bactericidal properties of polylactide (PLA) films containing three different polyhexamethylene guanidine hydrochloride (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. All PHMG derivatives had a slightly stronger bactericidal effect on Staphylococcus aureus than on E. coli but only PHMG granular polyethylene wax (at the concentration of at least 0.6 %) has a bactericidal effect. PHMG derivatives introduced into PLA affected the activity of microbial hydrolases to a small extent. This means that the introduction of PHMG derivatives into PLA will not reduce its enzymatic biodegradation significantly. On the other hand, PHMG derivatives introduced into PLA strongly affected dehydrogenases activity in S. aureus than in E. coli.

  9. Synergistic antibacterial effects of β-lactam antibiotic combined with silver nanoparticles

    Science.gov (United States)

    Li, Ping; Li, Juan; Wu, Changzhu; Wu, Qingsheng; Li, Jian

    2005-09-01

    The bactericidal action of silver (0) nanoparticles and amoxicillin on Escherichia coli is studied, respectively. Increasing concentration of both amoxicillin (0-0.525 mg ml-1) and silver nanoparticles (0-40 µg ml-1) showed a higher antibacterial effect in Luria-Bertani (LB) medium. Escherichia coli cells have different bactericidal sensitivity to them. When amoxicillin and silver nanoparticles are combined, it results in greater bactericidal efficiency on Escherichia coli cells than when they were applied separately. Dynamic tests on bacterial growth indicated that exponential and stationary phases are greatly decreased and delayed in the synergistic effect of amoxicillin and silver nanoparticles. In addition, the effect induced by a preincubation with silver nanoparticles is examined. The results show that solutions with more silver nanoparticles have better antimicrobial effects. One hypothesized mechanism is proposed to explain this phenomenon.

  10. How about food irradiation? Its history and usefulness. (3) Irradiation effects on food and decrease in fungi

    International Nuclear Information System (INIS)

    Inhibiting germination of vegetables and grade control of maturity of fruits, destroy of insect pest and parasite, disinfection of meats and fishes, bactericidal action of dry foods such as spices, and taste and color change of irradiated foods and perfect bactericidal action are stated. Application of food irradiation contains inhibiting germination, insecticidal action, sterilization of insect pest, grade control of maturity, inhibition of food poisoning, decrease in fungi, improvement of properties, and perfect bactericidal action. Each treatment of foods is described by the effects of three exposure doses such as the low exposure dose until 1 kGy, middle exposure dose from 1 to 10 kGy and high from 10 to 75 kGy. (S.Y.)

  11. Activity of ceftobiprole compared with those of other agents against Staphylococcus aureus strains with different resistotypes by time-kill analysis.

    Science.gov (United States)

    Lin, Gengrong; Appelbaum, Peter C

    2008-02-01

    Among 10 hospital- and community-acquired Staphylococcus aureus strains with differing methicillin and vancomycin resistotypes, all strains were susceptible to ceftobiprole at MICs quinupristin/dalfopristin. Ceftobiprole, at 4x MIC, was bactericidal (99.9% killing) against 9 of 10 strains tested at 4x MIC after 24 h. Ceftobiprole also yielded significant activity at earlier periods, with 90% killing of all strains at 2x MIC at 6 and 12 h. Vancomycin was bactericidal against 6 of 8 strains tested at 2x MIC after 24 h. By contrast, linezolid and tigecycline were mainly bacteriostatic, and quinupristin/dalfopristin was bactericidal against 4 of 10 strains at 2x MIC after 24 h. PMID:17997257

  12. Quantitative evaluation of dermatological antiseptics.

    Science.gov (United States)

    Leitch, C S; Leitch, A E; Tidman, M J

    2015-12-01

    Topical antiseptics are frequently used in dermatological management, yet evidence for the efficacy of traditional generic formulations is often largely anecdotal. We tested the in vitro bactericidal activity of four commonly used topical antiseptics against Staphylococcus aureus, using a modified version of the European Standard EN 1276, a quantitative suspension test for evaluation of the bactericidal activity of chemical disinfectants and antiseptics. To meet the standard for antiseptic effectiveness of EN 1276, at least a 5 log10 reduction in bacterial count within 5 minutes of exposure is required. While 1% benzalkonium chloride and 6% hydrogen peroxide both achieved a 5 log10 reduction in S. aureus count, neither 2% aqueous eosin nor 1 : 10 000 potassium permanganate showed significant bactericidal activity compared with control at exposure periods of up to 1 h. Aqueous eosin and potassium permanganate may have desirable astringent properties, but these results suggest they lack effective antiseptic activity, at least against S. aureus.

  13. Fe-S cluster biosynthesis controls uptake of aminoglycosides in a ROS-less death pathway.

    Science.gov (United States)

    Ezraty, Benjamin; Vergnes, Alexandra; Banzhaf, Manuel; Duverger, Yohann; Huguenot, Allison; Brochado, Ana Rita; Su, Shu-Yi; Espinosa, Leon; Loiseau, Laurent; Py, Béatrice; Typas, Athanasios; Barras, Frédéric

    2013-06-28

    All bactericidal antibiotics were recently proposed to kill by inducing reactive oxygen species (ROS) production, causing destabilization of iron-sulfur (Fe-S) clusters and generating Fenton chemistry. We find that the ROS response is dispensable upon treatment with bactericidal antibiotics. Furthermore, we demonstrate that Fe-S clusters are required for killing only by aminoglycosides. In contrast to cells, using the major Fe-S cluster biosynthesis machinery, ISC, cells using the alternative machinery, SUF, cannot efficiently mature respiratory complexes I and II, resulting in impendence of the proton motive force (PMF), which is required for bactericidal aminoglycoside uptake. Similarly, during iron limitation, cells become intrinsically resistant to aminoglycosides by switching from ISC to SUF and down-regulating both respiratory complexes. We conclude that Fe-S proteins promote aminoglycoside killing by enabling their uptake.

  14. Quantitative evaluation of dermatological antiseptics.

    Science.gov (United States)

    Leitch, C S; Leitch, A E; Tidman, M J

    2015-12-01

    Topical antiseptics are frequently used in dermatological management, yet evidence for the efficacy of traditional generic formulations is often largely anecdotal. We tested the in vitro bactericidal activity of four commonly used topical antiseptics against Staphylococcus aureus, using a modified version of the European Standard EN 1276, a quantitative suspension test for evaluation of the bactericidal activity of chemical disinfectants and antiseptics. To meet the standard for antiseptic effectiveness of EN 1276, at least a 5 log10 reduction in bacterial count within 5 minutes of exposure is required. While 1% benzalkonium chloride and 6% hydrogen peroxide both achieved a 5 log10 reduction in S. aureus count, neither 2% aqueous eosin nor 1 : 10 000 potassium permanganate showed significant bactericidal activity compared with control at exposure periods of up to 1 h. Aqueous eosin and potassium permanganate may have desirable astringent properties, but these results suggest they lack effective antiseptic activity, at least against S. aureus. PMID:26456933

  15. Titania sol-gel coatings with silver on non-porous titanium and titanium alloys

    Science.gov (United States)

    Horkavcova, D.; Cerny, M.; Sanda, L.; Novak, P.; Jablonska, E.; Zlamalova-Cflova, Z.; Helebrant, A.

    2016-04-01

    The objective of the work was to prepare and characterize titania sol-gel coatings on non-porous titanium and newly developed titanium alloys. Basic titania sol contained two forms of silver. Titania sol without silver was used as a reference sample. Coatings were prepared by dip-coating technique during stirring and fired. Coatings after firing were characterized by scanning electron microscopy. All titania coatings were measured to determine their adhesive and bactericidal properties. Adhesion of the coatings to the substrate was measured by tape test. Gram-negative bacteria E. coli was used for the bactericidal test. Coated substrates were immersed into suspension of E. coli in physiological solution for 24 hours. The in vitro cytotoxicity test was performed after one day. The bactericidal effect without toxicity was confirmed for selected coatings.

  16. Antibacterial Efficacy of Lytic Bacteriophages against Antibiotic-Resistant Klebsiella Species

    Directory of Open Access Journals (Sweden)

    M. Khajeh Karamoddini

    2011-01-01

    Full Text Available Bacterial resistance to antibiotics is a leading and highly prevalent problem in the treatment of infectious diseases. Bacteriophages (phages appear to be effective and safe alternatives for the treatment of resistant infections because of their specificity for bacterial species and lack of infectivity in eukaryotic cells. The present study aimed to isolate bacteriophages against Klebsiella spp. and evaluate their efficacy against antibiotic-resistant species. Seventy-two antibiotic-resistant Klebsiella spp. were isolated from samples of patients who referred to the Ghaem Hospital (Mashhad, Iran. Lytic bacteriophages against Klebsiella spp. were isolated from wastewater of the septic tank of the same hospital. Bactericidal activity of phages against resistant Klebsiella spp. was tested in both liquid (tube method; after 1 and 24 h of incubation and solid (double-layer agar plate method; after 24 h of incubation phases. In each method, three different concentrations of bacteriophages (low: 107 PFU/mL were used. Bacteriophages showed promising bactericidal activity at all assessed concentrations, regardless of the test method and duration of incubation. Overall, bactericidal effects were augmented at higher concentrations. In the tube method, higher activity was observed after 24 h of incubation compared to the 1-h incubation. The bactericidal effects were also higher in the tube method compared to the double-layer agar plate method after 24 h of incubation. The findings of the present study suggest that bacteriophages possess effective bactericidal activity against resistant Klebsiella spp. These bactericidal activities are influenced by phage concentration, duration of incubation, and test method.

  17. Antibacterial efficacy of lytic bacteriophages against antibiotic-resistant Klebsiella species.

    Science.gov (United States)

    Karamoddini, M Khajeh; Fazli-Bazzaz, B S; Emamipour, F; Ghannad, M Sabouri; Jahanshahi, A R; Saed, N; Sahebkar, A

    2011-07-07

    Bacterial resistance to antibiotics is a leading and highly prevalent problem in the treatment of infectious diseases. Bacteriophages (phages) appear to be effective and safe alternatives for the treatment of resistant infections because of their specificity for bacterial species and lack of infectivity in eukaryotic cells. The present study aimed to isolate bacteriophages against Klebsiella spp. and evaluate their efficacy against antibiotic-resistant species. Seventy-two antibiotic-resistant Klebsiella spp. were isolated from samples of patients who referred to the Ghaem Hospital (Mashhad, Iran). Lytic bacteriophages against Klebsiella spp. were isolated from wastewater of the septic tank of the same hospital. Bactericidal activity of phages against resistant Klebsiella spp. was tested in both liquid (tube method; after 1 and 24 h of incubation) and solid (double-layer agar plate method; after 24 h of incubation) phases. In each method, three different concentrations of bacteriophages (low: 10(7) PFU/mL) were used. Bacteriophages showed promising bactericidal activity at all assessed concentrations, regardless of the test method and duration of incubation. Overall, bactericidal effects were augmented at higher concentrations. In the tube method, higher activity was observed after 24 h of incubation compared to the 1-h incubation. The bactericidal effects were also higher in the tube method compared to the double-layer agar plate method after 24 h of incubation. The findings of the present study suggest that bacteriophages possess effective bactericidal activity against resistant Klebsiella spp. These bactericidal activities are influenced by phage concentration, duration of incubation, and test method.

  18. Photocatalytic and biocidal activities of novel coating systems of mesoporous and dense TiO{sub 2}-anatase containing silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roldán, María V. [Laboratorio de Materiales Cerámicos, FCEIA-UNR, IFIR-CONICET, Pellegrini 250, Rosario S2000BTP (Argentina); Oña, Paula de [Laboratorio de Microbiología Molecular, FCByF-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Castro, Yolanda; Durán, Alicia [Instituto de Cerámica y Vidrio (CSIC), Campus de Cantoblanco, 28049, Madrid (Spain); Faccendini, Pablo; Lagier, Claudia [IQUIR-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Grau, Roberto, E-mail: robertograu@fulbrightmail.org [Laboratorio de Microbiología Molecular, FCByF-UNR-CONICET, Suipacha 531, Rosario S2002LRK (Argentina); Pellegri, Nora S., E-mail: pellegri@fceia.unr.edu.ar [Laboratorio de Materiales Cerámicos, FCEIA-UNR, IFIR-CONICET, Pellegrini 250, Rosario S2000BTP (Argentina)

    2014-10-01

    Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise a layer of SiO{sub 2} followed by a layer of mesoporous or dense TiO{sub 2}-anatase, and doping with silver nanoparticles (Ag NPs). The coatings were synthesized via a sol–gel technique by combining colloidal Ag NPs with TiO{sub 2} and SiO{sub 2} sols. The photocatalytic activity was studied through methyl orange decomposition under UV light. Results showed a great increase of photocatalytic activity by Ag NPs doping. The most active photocatalyst corresponded to the Ag–SiO{sub 2}/TiO{sub 2} mesoporous system, associated with the porosity of the coatings and with the decrease of e–h recombination for the presence of Ag NPs. All the TiO{sub 2} coatings showed a strong bactericidal activity against planktonic forms of Gram-negative (enterohemorrhagic Escherichia coli) and Gram-positive (Listeria monocytogenes) pathogens, as well as a strong germicidal effect against deadly spores of human gas gangrene- and anthrax-producing bacteria (Clostridium perfringens and Bacillus anthracis, respectively). The bactericidal and sporocidal activity was improved by doping the coatings with Ag NPs, even more when nanoparticles were in the outer layer of TiO{sub 2}, because they are more accessible to the environment. The mechanisms responsible for the increase of photocatalytic and bactericidal behaviors related to Ag NP doping were studied by spectroscopic ellipsometry, UV–vis spectroscopy, photoluminescence and anodic stripping voltammetry. It was found that the separation of the electron–hole pair contributed to the enhancement of photocatalysis, whereas the effect of the local electric field reinforcement was probably present. A possible involvement of a decrease of band-gap energy and dispersion by silver nanoparticles is ruled out. bactericidal efficacy was increased by Ag{sup +} ion release. Overall, the results

  19. Preventive biocenosis of oil strata and combatting microbiological corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Asfandiyarov, F.A.; Kildibekov, I.G.; Nizamov, K.R.

    1984-01-01

    The following conclusions are drawn on the basis of the conducted studies: the use of chemical reagents (bactericides or bacterial corrosion inhibitors) is a rational way to combat sulfate reduction in oil strata and microbiological corrosion; the use of bactericides in the early stage of development is an effective method for sterilizing the pumped water to prevent contamination of the productive strata with sulfate reducing bacteria (SVB) and microbiological corrosion and the use of bacterial corrosion inhibitors is an effective method for suppressing microbiological corrosion and reducing sulfate reduction in the later stage of development.

  20. Production of stable isotope enriched antimicrobial peptides in Escherichia coli: An application to the production of a 15N-enriched fragment of lactoferrin

    International Nuclear Information System (INIS)

    A method is described for the production of recombinant isotopically enriched peptides in E. coli. Peptides are produced in high yield as fusion proteins with ketosteroid isomerase which form insoluble inclusion bodies. This insoluble form allows easy purification, stabilizes the peptide against degradation and prevents bactericidal activity of the peptide. Cyanogen bromide cleavage released peptide which was conjugated with alkylamines to form lipopeptide. An important advantage of this system is that it allows production of peptides that are toxic to bacteria, which we have demonstrated on a dodecapeptide based on residues 21-31 of human bactericidal protein lactoferrin

  1. Synthesis and biological activity of acetates of copper (II and iron (III for the control of Aedes aegypti (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Jéssica V. Nardeli

    2012-06-01

    Full Text Available This work aimed to the synthesis of basic acetates of Cu (II and Fe(III against larvae of Aedes aegypti and Gram negative and Gram positive. The transition metal ions Cu (II and Fe (III have bactericidal activity and are toxic to Aedes aegypti larvae in the eggs and larval stages of initial, precludes the eggs hatch and slow reproductive cycle of the insect. The theme investigates the importance of carboxyl groups in complex formation, transport and cellular internalization of the toxic ions. It is known that the bactericide or insecticide activity is due to metal ions and Cu (IIor Fe (III.

  2. Survival and Filamentation of Salmonella enterica Serovar Enteritidis PT4 and Salmonella enterica Serovar Typhimurium DT104 at Low Water Activity

    OpenAIRE

    Mattick, K. L.; Jørgensen, F.; Legan, J. D.; Cole, M. B.; Porter, J.(Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA); Lappin-Scott, H M; Humphrey, T. J.

    2000-01-01

    In this study we investigated the long-term survival of and morphological changes in Salmonella strains at low water activity (aw). Salmonella enterica serovar Enteritidis PT4 and Salmonella enterica serovar Typhimurium DT104 survived at low aw for long periods, but minimum humectant concentrations of 8% NaCl (aw, 0.95), 96% sucrose (aw, 0.94), and 32% glycerol (aw, 0.92) were bactericidal under most conditions. Salmonella rpoS mutants were usually more sensitive to bactericidal levels of NaC...

  3. CHARACTERISTIC OF SENSITIVITY OF STAPHYLOCOCCUS AUREUS AND CANDIDA ALBICANS TO ANTIBACTERIAL PREPARATIONS AND COLLOIDAL SILVER

    Directory of Open Access Journals (Sweden)

    I. A. Afonina

    2011-01-01

    Full Text Available Abstract. Constant use of antibiotics leads to reliable increasing of resistance among microorganisms. Using non-toxic concentrations of colloidal silver in combination with antimicrobial agents can reduce using concentrations of antibiotics, kept necessary antimicrobial effect. In case of Staphylococcus aureus bactericidal activity of the complex of colloidal silver with unit concentration of neomycin is bigger than the bactericidal effect of double concentration of the antibiotic. Fungicidal effect of combination of antifungal agents with a solution of the colloidal silver on Candida albicans is equal to fungicidal effect of double concentration of antifungal drugs.

  4. Photocatalytic and biocidal activities of novel coating systems of mesoporous and dense TiO2-anatase containing silver nanoparticles

    International Nuclear Information System (INIS)

    Here we describe the development of novel nanostructured coating systems with improved photocatalytic and antibacterial activities. These systems comprise a layer of SiO2 followed by a layer of mesoporous or dense TiO2-anatase, and doping with silver nanoparticles (Ag NPs). The coatings were synthesized via a sol–gel technique by combining colloidal Ag NPs with TiO2 and SiO2 sols. The photocatalytic activity was studied through methyl orange decomposition under UV light. Results showed a great increase of photocatalytic activity by Ag NPs doping. The most active photocatalyst corresponded to the Ag–SiO2/TiO2 mesoporous system, associated with the porosity of the coatings and with the decrease of e–h recombination for the presence of Ag NPs. All the TiO2 coatings showed a strong bactericidal activity against planktonic forms of Gram-negative (enterohemorrhagic Escherichia coli) and Gram-positive (Listeria monocytogenes) pathogens, as well as a strong germicidal effect against deadly spores of human gas gangrene- and anthrax-producing bacteria (Clostridium perfringens and Bacillus anthracis, respectively). The bactericidal and sporocidal activity was improved by doping the coatings with Ag NPs, even more when nanoparticles were in the outer layer of TiO2, because they are more accessible to the environment. The mechanisms responsible for the increase of photocatalytic and bactericidal behaviors related to Ag NP doping were studied by spectroscopic ellipsometry, UV–vis spectroscopy, photoluminescence and anodic stripping voltammetry. It was found that the separation of the electron–hole pair contributed to the enhancement of photocatalysis, whereas the effect of the local electric field reinforcement was probably present. A possible involvement of a decrease of band-gap energy and dispersion by silver nanoparticles is ruled out. bactericidal efficacy was increased by Ag+ ion release. Overall, the results included in this article show that the architecture of

  5. Graphitic C3 N4 -Sensitized TiO2 Nanotube Layers: A Visible-Light Activated Efficient Metal-Free Antimicrobial Platform.

    Science.gov (United States)

    Xu, Jingwen; Li, Yan; Zhou, Xuemei; Li, Yuzhen; Gao, Zhi-Da; Song, Yan-Yan; Schmuki, Patrik

    2016-03-14

    Herein, we use a facile procedure to graft a thin graphitic C3N4 (g-C3N4) layer on aligned TiO2 nanotube arrays (TiNT) by a one-step chemical vapor deposition (CVD) approach. This provides a platform to enhance the visible-light response of TiO2 nanotubes for antimicrobial applications. The formed g-C3N4/TiNT binary nanocomposite exhibits excellent bactericidal efficiency against Escherichia coli (E. coli) as a visible-light activated antibacterial coating, without the use of additional bactericides.

  6. Mutagenesis and reparation processes in the methylotrophic bacterium Pseudomonas methanolica after UV irradiation

    International Nuclear Information System (INIS)

    High resistance of cells of methylotrophic bacterium Pseudomonas methanolica to bactericidal and mutagenous effects of ultraviolet irradiation is shown as well as activity of reparation processes after UV irradiation. The presence of low photoreactivating activity in P. methanolica is shown as well. Observed recovery in innutritious medium and decrease of irradiated cells survival rates under effect of reparation inhibitors (coffeine and acriflavine) testify to activity of excision reparation and, perhaps, recombination branch of postreplicative reparation. No manifestation of inducible reparation system is discovered. It is concluded that increased resistance of P. methanolica cells to bactericidal and mutagenous effects of short-wave ultraviolet radiation is related to activity of exact reparation systems

  7. Toxicity of laser irradiated photoactive fluoride PrF3 nanoparticles toward bacteria

    Science.gov (United States)

    Pudovkin, M. S.; Korableva, S. L.; Krasheninnicova, A. O.; Nizamutdinov, A. S.; Semashko, V. V.; Zelenihin, P. V.; Alakshin, E. M.; Nevzorova, T. A.

    2014-11-01

    The article is devoted to exploration of biological effects of crystalline PrF3 nanoparticles toward Salmonella typhimurium TA 98 bacteria under the laser irradiation. Obtained results show bactericidal activity of PrF3 nanoparticles and optimal parameters of laser irradiation (power of laser irradiation, wavelength, diameter of the laser spoil, and exposure time) have been found under which the effects of bactericidal activity become the most significant. Survival of bacterial cells under laser irradiation with wavelength 532 nm in colloidal solution of PrF3 nanoparticles was 39%, 34%, 20% for exposure times 5 minutes, 15 minutes and 30 minutes, correspondingly.

  8. Moxifloxacin in the Therapy of Experimental Pneumococcal Meningitis

    OpenAIRE

    Schmidt, H.; Dalhoff, A.; Stuertz, K; Trostdorf, F.; Chen, V.; Schneider, O.; Kohlsdorfer, C.; BRÜCK, W.; Nau, R.

    1998-01-01

    The activity of moxifloxacin (BAY 12-8039) against a Streptococcus pneumoniae type 3 strain (MIC and minimum bactericidal concentration [MBC] of moxifloxacin, 0.06 and 0.25 μg/ml, respectively; MIC and MBC of ceftriaxone, 0.03 and 0.06 μg/ml, respectively) was determined in vitro and in a rabbit model of meningitis. Despite comparable bactericidal activity, 10 μg of moxifloxacin per ml released lipoteichoic and teichoic acids less rapidly than 10 μg of ceftriaxone per ml in vitro. Against exp...

  9. Volatiles from Coriandrum sativum: comparation of in vitro and ex vitro grown plants

    OpenAIRE

    Cardoso, Susana M.; Dias, I; Sousa, Maria João; Figueiredo, A. Cristina; Barroso, J. G.; Pedro, Luís G.

    2010-01-01

    Coriandrum sativum (coriander) is commonly used, raw or cooked, in Portuguese Gastronomy. Coriander is also used in traditional medicine as a carminative and as a digestive aid. The fruits essential oil is used in food flavouring and in perfumery and is also responsible for the digestive and stimulant effect as well as for fungicide and bactericidal activity.

  10. Relationship between perioperative glycemic control and postoperative infections

    OpenAIRE

    Hanazaki, Kazuhiro; Maeda, Hiromichi; Okabayashi, Takehiro

    2009-01-01

    Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause of infection and improve with tight glycemic control, which leads to fewer POIs in critically i...

  11. Genetics of Serum Resistance in Neisseria gonorrhoeae: The sac-1 Genetic Locus

    OpenAIRE

    Cannon, Janne G.; Lee, Terrence J.; Guymon, Lawrence F.; Sparling, P. Frederick

    1981-01-01

    A genetic locus affecting susceptibility to the bactericidal activity of normal human serum has been designated sac-1. This locus was shown to be closely linked to, but not identical with, a second locus (designated nmp-2) that affects protein 1 of the outer membrane. The sac-1 locus could be linked to known antibiotic resistance markers on the gonococcal chromosome by genetic transformation.

  12. Organic Matter Application Can Reduce Copper Toxicity in Tomato Plants

    Science.gov (United States)

    Campbell, Brian

    2010-01-01

    Copper fungicides and bactericides are often used in tomato cultivation and can cause toxic Cu levels in soils. In order to combat this, organic matter can be applied to induce chelation reactions and form a soluble complex by which much of the Cu can leach out of the soil profile or be taken up safely by plants. Organic acids such as citric,…

  13. An antibacterial assay of aqueous extract of garlic against anaerobic/microaerophilic and aerobic bacteria

    OpenAIRE

    Elsom, Giles K.; Hide, Denis; Salmon, David M.

    2011-01-01

    Both the minimum inhibitory and minimum bactericidal concentration (expressed in terms of thiosulphinate concentration) of an aqueous extract of garlic was determined against nine species of bacteria. Helicobacter pylori proved to be extremely sensitive to garlic extract, whilst Bacteroides fragilis, Clostridium perfringens, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium and Staphylococcus aureus all were moderately sensitive to the garlic extract treat...

  14. Antimycobacterial activity of bacteriocins and their complexes with liposomes

    Science.gov (United States)

    Bacteriocins (Bcn) are natural peptides that are secreted by taxonomically distinct bacteria which exert bactericidal activity against other bacterial species. Their capacity to inhibit growth of virulent Mycobacterium tuberculosis H37Rv was evaluated in this study. Five Bcn were purified from sel...

  15. Colloidal metal oxide nanoparticle systems: the new promising way to prevent antibiotic resistance during treatment of local infectious processes

    Science.gov (United States)

    Karasenkov, Y.; Frolov, G.; Pogorelsky, I.; Latuta, N.; Gusev, A.; Kuznetsov, D.; Leont'ev, V.

    2015-11-01

    New bactericidal containing nanoparticles colloids for application in dentistry, maxillofacial surgery, urology, obstetrics, gynaecology, ENT, proctology have been developed. The various water colloidal nanodispersive systems of metals and oxides have been obtained by means of electric impulse - condensation (electroerosion) method. These systems are based pure elements and alloys of argentum (Ag), titanium dioxide (TiO2), iron oxide (Fe2O3), tantalum oxide (TaO), vanadium oxide (VO2), cobalt oxide (CoO), tantalum dioxide TaO2, zinc oxide (ZnO), copper oxide (CuO) and mixed suspensions of titanium, aluminium and molybdenum oxides. The research has been made on culture of dentobacterial plaque and mixed culture issued from gingival spaces. The composition of culture was identified with S.aureus, S.epidermidis and nonfermentable kinds of E.coli. The observation period lasted more than nineteen days. All solutions showed highly prolonged bactericidal activity in dilutions from the whole solution 1-20 mg/L. The bactericidal activity of powder specimen of silica containing Ag and Fe2O3 nanoparticles used as dental filling material and disintegrates of composite materials (produced by “StomaDent” CJSC) have been studied. Tested materials have long (up to 19 days and more) bactericidal activity.

  16. Antibacterial and Antibiofilm Effect of Low Viscosity Chitosan against Staphylococcus epidermidis.

    Science.gov (United States)

    Dragland, Inger Sofie; Rukke, Håkon Valen; Stenhagen, Ida S R; Lönn-Stensrud, Jessica; Kopperud, Hilde M

    2016-01-01

    Aim. The aim of this study was to investigate the antibacterial and antibiofilm properties of low viscosity chitosan on S. epidermidis growth and biofilm formation. Methods and Results. The antibacterial and antibiofilm properties were investigated, during both planktonic growth and biofilm formation. This was performed using different concentrations in media and by coating on polystyrene surfaces. In addition, the bactericidal effect was investigated using a modified direct contact test. The results showed that low viscosity chitosan in media had both a bacteriostatic and bactericidal effect on planktonic growth and biofilm formation of S. epidermidis in a concentration dependent manner. Polystyrene discs coated with chitosan reduced both early biofilm formation (6 h) and late biofilm formation (18 h), as confirmed by scanning electron microscopy. The modified direct contact test showed a bactericidal effect. Conclusion. This study demonstrated that low viscosity chitosan has a bacteriostatic and bactericidal activity against S. epidermidis and that the activity is dependent on the amount of chitosan added. In addition, low viscosity chitosan reduced biofilm formation both when added to media and when coated on polystyrene surfaces. Significance and Impact of Study. Low viscosity chitosan could be a contribution to new treatment approaches of biofilm-related infections of S. epidermidis. PMID:27635144

  17. Safe, Effective Use of Pesticides, A Manual for Commercial Applicators: Fruit Pest Control.

    Science.gov (United States)

    Brunner, J.; And Others

    This manual is intended to assist pesticide applicators prepare for certification under the Michigan Pesticide Control Act of 1976. The primary focus of this publication is on fruit pest control. Sections included are: (1) Causes of fruit diseases; (2) Fruit fungicides and bactericides; (3) Insect and mite pests; (4) Insecticides and miticides;…

  18. Survival of adhering staphylococci during exposure to a quaternary ammonium compound evaluated by using atomic force microscopy imaging

    NARCIS (Netherlands)

    Crismaru, Mihaela; Asri, Lia ATW; Loontjens, Jacobus; Krom, Bastiaan P; de Vries, Jacob; van der Mei, Henderina; Busscher, Hendrik

    2011-01-01

    Effects of a quaternary ammonium compound (QAC) on the survival of adhering staphylococci on a surface were investigated using atomic force microscopy (AFM). Four strains with different minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) for the QAC were exposed to

  19. Influence of ethylenediaminetetraacetic acid (EDTA) on the on the ability of fatty acids to inhibit the growth of bacteria associated with poultry processing.

    Science.gov (United States)

    The effect of ethylenediaminetetraacetic acid (EDTA) on the bactericidal activity of alkaline salts of fatty acids was examined. A 0.5 M concentration of caproic, caprylic, capric, and lauric acids was dissolved in 1.0 M potassium hydroxide (KOH), and then supplemented with 0, 5, or 10 mM of EDTA. T...

  20. Taking Out TB–Lysosomal Trafficking and Mycobactericidal Ubiquitin-Derived Peptides

    OpenAIRE

    Purdy, Georgiana E.

    2011-01-01

    Tuberculosis remains a significant global health concern. The hallmark of Mycobacterium tuberculosis pathogenicity is its ability to infect resting macrophages and establish an intracellular niche. Activated and autophagic macrophages control mycobacterial infections through bactericidal mechanisms ranging from reactive oxygen and nitrogen intermediates to the delivery of the bacterium to the acidified, hydrolytically active lysosome. The mycobactericidal activity of the lysosome is due in pa...

  1. Taking out TB – A role for lysosomal ubiquitin-derived peptides

    OpenAIRE

    Georgiana ePurdy

    2011-01-01

    Tuberculosis remains a significant global health concern. The hallmark of Mycobacterium tuberculosis pathogenicity is its ability to infect resting macrophages and establish an intracellular niche. Activated and autophagic macrophages control mycobacterial infections through bactericidal mechanisms ranging from reactive oxygen and nitrogen intermediates to the delivery of the bacterium to the acidified, hydrolytically active lysosome. The mycobactericidal activity of the lysosome is due in pa...

  2. Activity of ozonated water and ozone against Staphylococcus aureus and Pseudomonas aeruginosa biofilms

    Science.gov (United States)

    Bialoszewski, Dariusz; Pietruczuk-Padzik, Anna; Kalicinska, Agnieszka; Bocian, Ewa; Czajkowska, Magdalena; Bukowska, Bozena; Tyski, Stefan

    2011-01-01

    Summary Background The known bactericidal properties of ozone have not been checked in relation to its action on bacterial biofilms. This is especially true of ozonated fluids. The aim of this study was to investigate the bactericidal activity of ozonated water and that of a mixture of ozone and oxygen against biofilms. Material/Methods Eighteen clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa exhibiting various levels of antibiotic sensitivity were investigated. Bacteria were cultured in biofilm form on polystyrene titration plates for periods of 2 to 72 hours. The biofilms formed in this way were exposed to in statu nascendi ozonated water produced in a prototype device that had been tested in clinical conditions, or to a mixture of oxygen and ozone generated in the same device. Live cells in the biofilm were stained with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide solution. The degree of reduction of viable bacteria following ozone exposure was determined. Results Ozonated water was found to be an effective bactericidal agent against biofilms after as little as 30 seconds of exposure, while the bactericidal activity of the ozone-oxygen solution was much lower. Prolongation of the duration of biofilm exposure to the gaseous disinfectant to 40 minutes led to a reduction in the viable cell count, which nevertheless remained high. Conclusions Unlike the ozone-oxygen mixture, ozonated water effectively destroys bacterial biofilms in vitro. PMID:22037737

  3. Soya bean tempe extracts show antibacterial activity against Bacillus cereus cells and spores

    NARCIS (Netherlands)

    Roubos-van den Hil, P.J.; Dalmas, E.; Nout, M.J.R.; Abee, T.

    2010-01-01

    Aims: Tempe, a Rhizopus ssp.-fermented soya bean food product, was investigated for bacteriostatic and/or bactericidal effects against cells and spores of the food-borne pathogen Bacillus cereus. Methods and results: Tempe extract showed a high antibacterial activity against B. cereus ATCC 14579 bas

  4. Identification of copper-induced genes in Pseudomonas fluorescens and use of a reporter strain to monitor bioavailable copper in soil

    DEFF Research Database (Denmark)

    Tom-Petersen, Andreas; Hosbond, Carsten; Nybroe, Ole

    2001-01-01

    Copper (Cu) is an essential trace metal required by living organisms but it is potentially toxic at higher concentrations. Cu salts are used as bactericides in agriculture and as growth promoters in pig production. They are consequently introduced to the environment, e.g. through manure, and migh...

  5. A validated spectrofluorimetric method for the determination of nifuroxazide through coumarin formation using experimental design

    OpenAIRE

    El-Zaher, Asmaa Ahmed; Mahrouse, Marianne Alphonse

    2013-01-01

    Background Nifuroxazide (NF) is an oral nitrofuran antibiotic, having a wide range of bactericidal activity against gram positive and gram negative enteropathogenic organisms. It is formulated either in single form, as intestinal antiseptic or in combination with drotaverine (DV) for the treatment of gastroenteritis accompanied with gastrointestinal spasm. Spectrofluorimetry is a convenient and sensitive technique for pharmaceutical quality control. The new proposed spectrofluorimetric method...

  6. Anticariogenic activity of some tropical medicinal plants against Streptococcus mutans.

    Science.gov (United States)

    Hwang, Jae-Kwan; Shim, Jae-Seok; Chung, Jae-Youn

    2004-09-01

    The methanol extracts of five tropical plants, Baeckea frutescens, Glycyrrhiza glabra, Kaempferia pandurata, Physalis angulata and Quercus infectoria, exhibited potent antibacterial activity against the cariogenic bacterium Streptococcus mutans. In particular, G. glabra, K. pandurata and P. angulata conferred fast killing bactericidal effect against S. mutans in 2 min at 50 microg/ml of extract concentration. PMID:15351117

  7. In vitro antiplaque activity of octenidine dihydrochloride (WIN 41464-2) against preformed plaques of selected oral plaque-forming microorganisms.

    OpenAIRE

    Slee, A M; O'Connor, J R

    1983-01-01

    The antibacterial activity of octenidine dihydrochloride (WIN 41464-2) against intact preformed in vitro plaques of four indigenous oral plaque-forming microorganisms, Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, and Actinomyces naeslundii, was studied. Both absolute (plaque bactericidal index) and relative (chlorhexidine coefficient) indices of antiplaque efficacy were established. Octenidine dihydrochloride compared favorably with chlorhexidine digluconate with respect...

  8. Paneth cell extrusion and release of antimicrobial products is directly controlled by immune cell-derived IFN-γ

    NARCIS (Netherlands)

    Farin, Henner F; Karthaus, Wouter R; Kujala, Pekka; Rakhshandehroo, Maryam; Schwank, Gerald; Vries, Robert G J; Kalkhoven, Eric; Nieuwenhuis, Edward E S; Clevers, Hans

    2014-01-01

    Paneth cells (PCs) are terminally differentiated, highly specialized secretory cells located at the base of the crypts of Lieberkühn in the small intestine. Besides their antimicrobial function, PCs serve as a component of the intestinal stem cell niche. By secreting granules containing bactericidal

  9. Action of plasma jets of a low-current spark discharge on microorganisms ( Escherichia coli)

    Science.gov (United States)

    Baldanov, B. B.; Semenov, A. P.; Ranzhurov, Ts. V.; Nikolaev, E. O.; Gomboeva, S. V.

    2015-11-01

    High efficiency of bactericide action of cold argon plasma generated by plasma jets of a weak-current spark discharge under atmospheric pressure is demonstrated. It is found that an increase in the time of treatment with plasma jets from a low-current spark discharge makes it possible to effectively inactivate microorganisms over a much larger area.

  10. Antimicrobial properties of N-carboxybutyl chitosan.

    OpenAIRE

    Muzzarelli, R; Tarsi, R; Filippini, O; Giovanetti, E; G. Biagini; Varaldo, P E

    1990-01-01

    N-Carboxybutyl chitosan, a modified chitin of crustacean origin, displayed inhibitory, bactericidal, and candidacidal activities when tested against 298 cultures of various pathogens. Examination by electron microscopy showed that microbial cells exposed to N-carboxybutyl chitosan underwent marked morphological alterations. The data are of importance in defining the suitability of N-carboxybutyl chitosan as a wound dressing.

  11. Arylative Desulfonation of Diarylmethyl Phenyl Sulfone with Arenes Catalyzed by Scandium Triflate.

    Science.gov (United States)

    Nambo, Masakazu; Ariki, Zachary T; Canseco-Gonzalez, Daniel; Beattie, D Dawson; Crudden, Cathleen M

    2016-05-20

    A scandium-triflate-catalyzed arylative desulfonation of diarylmethyl phenyl sulfones with arenes and heteroarenes was established. A variety of both sulfone and arene substrates were reacted to afford symmetric and nonsymmetric triarylmethanes in good yields. Further transformations of the resulting triarylmethanes and application to the concise synthesis of a bactericidal agent analogue were also demonstrated. PMID:27124389

  12. In Vitro Susceptibility Testing of Four Antibiotics against Borrelia burgdorferi: a Comparison of Results for the Three Genospecies Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi Sensu Stricto

    OpenAIRE

    Sicklinger, Martin; Wienecke, Ralf; Neubert, Uwe

    2003-01-01

    MICs and minimal bactericidal concentrations (MBCs) were evaluated for the four antibiotics azithromycin, amoxicillin, ceftriaxone, and doxycycline against the three main genospecies of Borrelia burgdorferi sensu lato. In MBC testing, statistically significant differences between the genospecies could be found in 7 out of 12 comparative evaluations (P < 0.05).

  13. In-vitro-Sensibilität von Borrelia burgdorferi sensu lato gegenüber vier Antibiotika: ein Vergleich der Genospezies Borrelia afzelii, Borrelia garinii und Borrelia burgdorferi sensu stricto

    OpenAIRE

    Sicklinger, Martin

    2006-01-01

    MICs and minimal bactericidal concentrations (MBCs) were evaluated for the four antibiotics azithromycin, amoxicillin, ceftriaxone, and doxycycline against the three main genospecies of Borrelia burgdorferi sensu lato. In MBC testing, statistically significant differences between the genospecies could be found in 7 out of 12 comparative evaluations (P < 0.05).

  14. In vitro study on the effect of organic acids on Campylobacter jejuni/coli populations in mixtures of water and feed

    NARCIS (Netherlands)

    Chaveerach, P.; Keuzenkamp, D.A.; Urlings, H.A.P.; Lipman, L.J.A.; Knapen, van F.

    2002-01-01

    Gastroenteritis caused by Campylobacter spp. infection has been recognized as one of the important public health problems in the developed countries. Outbreaks mostly originate from the consumption of contaminated poultry or infected water. The aim of this study was to determine the bactericidal act

  15. Quantification and validation of ertapenem using a liquid chromatography-tandem mass spectrometry method

    NARCIS (Netherlands)

    van Rijn, S.P.; Wessels, A.M.A.; Greijdanus, B.; Touw, D.J.; Alffenaar, J.W.C.

    2014-01-01

    Ertapenem, a carbapenem, relies on time-dependent killing. Therapeutic drug monitoring (TDM) should be considered, when ertapenem is used in specific populations, to achieve optimal bactericidal activity and optimize drug-dosing regimens. No validated liquid chromatography-tandem mass spectrometry (

  16. Combined action of nisin and carvacrol on Bacillus cereus and Listeria monocytogenes

    NARCIS (Netherlands)

    Pol, I.E.; Smid, E.J.

    1999-01-01

    Nisin, a small antimicrobial protein, was tested for its bactericidal action against Listeria monocytogenes and Bacillus cereus and a typical biphasic reduction of the viable count was observed. The reduction was most fast during the first 10 min of exposure, while the viable count remained stable i

  17. Tuberculous Pericarditis is Multibacillary and Bacterial Burden Drives High Mortality

    Directory of Open Access Journals (Sweden)

    Jotam G. Pasipanodya

    2015-11-01

    Interpretation: Patients with culture confirmed tuberculous pericarditis have a high bacillary burden, and this bacterial burden drives mortality. Thus proven tuberculosis pericarditis is not a paucibacillary disease. Moreover, the severe immunosuppression suggests limited inflammation. There is a need for the design of a highly bactericidal regimen for this condition.

  18. In vitro activity of azithromycin against clinical isolates of Legionella species.

    OpenAIRE

    Edelstein, P H; Edelstein, M A

    1991-01-01

    The activities of azithromycin, erythromycin, and ciprofloxacin against 21 Legionella isolates were measured by an agar dilution method and in macrophages. The MICs for 90% of strains tested were 2.0, 1.0, and 0.5 micrograms/ml for azithromycin, erythromycin, and ciprofloxacin, respectively. Azithromycin and ciprofloxacin were both bactericidal in the macrophage system, but erythromycin was bacteriostatic.

  19. Determination of antibacterial activity of green coffee bean extract on periodontogenic bacteria like Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans: An in vitrostudy

    OpenAIRE

    Nagaraj Bharath; Nagur Karibasappa Sowmya; Dhoom Singh Mehta

    2015-01-01

    Background: The aim of this study was to evaluate the antibacterial activity of pure green coffee bean extract on periodonto pathogenic bacteria Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn) and Aggregatibacter actinomycetemcomitans (Aa). Materials and Methods: Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were used to assess the antibacterial effect of pure green coffee bean extract against periodonto pathogen...

  20. Degradation of Triclosan in aerated sludge

    DEFF Research Database (Denmark)

    Bester, Kai; Chen, Xijuan; Furgal, Karolina;

    Triclosan is a bactericide used in increasing shelflife of cosmetics, improving hygenics in sportswear as well as in toothpaste and in mouth wash. More than 350 tons Triclosan is annually produced in Europe, and most of it finally is emitted into wastewater at the end of its life cycle. Therefore...

  1. 21 CFR 1250.33 - Utensils and equipment.

    Science.gov (United States)

    2010-04-01

    ... provided to permit the determination of the hot water temperature when and where hot water is used as the bactericidal agent. (b) All multiuse eating and drinking utensils shall be thoroughly cleaned in warm water and... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  2. The involvement of donor specific CTL in cardiac transplant rejection: relevance of avidity

    NARCIS (Netherlands)

    N.E.M. van Emmerik (Nancy)

    1998-01-01

    textabstractWhen a micro-organism penetrates the body, defensive mechanisms of the non-specific innate immune system come into play, such as soluble chemical factors (bactericidal lysozyme, acute phase proteins, interferons), extracellular killing (NK cells, eosinophils), and phagocytosis (macrophag

  3. ヘルスケア繊維の介護福祉分野への応用

    OpenAIRE

    白井, 汪芳; 築城, 寿長

    2010-01-01

    Smart fibers and textiles having odor-removing, bactericidal,anti-allergy and anti-virus functions developed by our research group have applied to practical many health care goods. Apprication to the care welfare of these health care textiles are reviwed.

  4. Immunity to the Bacteriocin Sublancin 168 Is Determined by the SunI (YolF) Protein of Bacillus subtilis

    NARCIS (Netherlands)

    Dubois, Jean-Yves F.; Kouwen, Thijs R. H. M.; Schurich, Anna K. C.; Reis, Carlos R.; Ensing, Hendrik T.; Trip, Erik N.; Zweers, Jessica C.; van Dijl, Jan Maarten

    2009-01-01

    Bacillus subtilis strain 168 produces the extremely stable lantibiotic sublancin 168, which has a broad spectrum of bactericidal activity. Both sublancin 168 production and producer immunity are determined by the SP beta prophage. While the sunA and sunT genes for sublancin 168 production have been

  5. N-terminal aromatic residues closely impact the cytolytic activity of cupiennin 1a, a major spider venom peptide.

    Science.gov (United States)

    Kuhn-Nentwig, Lucia; Sheynis, Tania; Kolusheva, Sofiya; Nentwig, Wolfgang; Jelinek, Raz

    2013-12-01

    Cupiennins are small cationic α-helical peptides from the venom of the ctenid spider Cupiennius salei which are characterized by high bactericidal as well as hemolytic activities. To gain insight into the determinants responsible for the broad cytolytic activities, two analogues of cupiennin 1a with different N-terminal hydrophobicities were designed. The insecticidal, bactericidal and hemolytic activities of these analogues were assayed and compared to the native peptide. Specifically, substitution of two N-terminal Phe residues by Ala results in less pronounced insecticidal and cytolytic activity, whereas a substitution by Lys reduces strongly its bactericidal activity and completely diminishes its hemolytic activity up to very high tested concentrations. Biophysical analyses of peptide/bilayer membrane interactions point to distinct interactions of the analogues with lipid bilayers, and dependence upon membrane surface charge. Indeed, we find that lower hemolytic activity was correlated with less surface association of the analogues. In contrast, our data indicate that the reduced bactericidal activity of the two cupiennin 1a analogues likely correspond to greater bilayer-surface localization of the peptides. Overall, ultimate insertion and destruction of the host cell membrane is highly dependent on the presence of Phe-2 and Phe-6 (Cu 1a) or Leu-6 (Cu 2a) in the N-terminal sequences of native cupiennins.

  6. Antibacterial activities of magnesium oxide (MgO) nanoparticles against foodborne pathogens

    Science.gov (United States)

    The antibacterial activities of magnesium oxide nanoparticles (MgO NP) alone or in combination with other antimicrobials (nisin and ZnO NP) against E. coli O157:H7 and Salmonella Stanley were investigated. The results show that MgO NP have strong bactericidal activity against the pathogens, achievin...

  7. Antibacterial action of doped CoFe{sub 2}O{sub 4} nanocrystals on multidrug resistant bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Velho-Pereira, S.; Noronha, A.; Mathias, A.; Zakane, R.; Naik, V.; Naik, P. [Department of Biotechnology, St. Xavier' s College, Goa (India); Salker, A.V. [Department of Chemistry, Goa University, Goa (India); Naik, S.R., E-mail: srnaik19@gmail.com [Department of Chemistry, St. Xavier' s College, Goa (India)

    2015-07-01

    The bactericidal effect of pristine and doped cobalt ferrite nanoparticles has been evaluated against multiple drug resistant clinical strains by assessing the number of colony-forming units (CFU). Monophasic polycrystalline ferrites have been prepared by the malate–glycolate sol–gel autocombustion method as confirmed by the X-ray diffraction study. Various changes occurring during the preparative stages have been demonstrated using TG–DTA analysis which is well complemented by the FTIR spectroscopy. The antibacterial studies carried out demonstrate a bactericidal effect of the nanoparticles wherein the number of CFU has been found to decrease with doping. Cellular distortions have been revealed through SEM. Variation in the number of CFU with dopant type has also been reported herein. - Graphical abstract: Antibacterial action of doped cobalt ferrites resulting in the lyses of multi-drug resistant bacterial strains. - Highlights: • The paper reports an antibacterial study of rare earth doped cobalt ferrite nanoparticles. • Monophasic compounds have been prepared by the sol–gel autocombustion method. • Bactericidal property has been evaluated based on the number of colony forming units. • Variation in bactericidal action with respect to the dopant type has been observed. • Cellular distortions resulting in cell lysis are confirmed from the SEM images.

  8. Expression profiles of seven channel catfish antimicrobial peptides in response to Edwardsiella ictaluri infection

    Science.gov (United States)

    Using quantitative PCR technique, the relative transcriptional levels of seven channel catfish antimicrobial peptide (AMP) genes [NK-lysin type 1, NK-lysin type 2, NK-lysin type 3, bactericidal permeability-increasing protein (BPI), cathepsin D, hepcidin, and liver-expressed antimicrobial peptide 2 ...

  9. Microbial Oxidation of Pyrite Coupled to Nitrate Reduction in Anoxic Groundwater Sediment

    DEFF Research Database (Denmark)

    Jørgensen, Christian Juncher; Elberling, Bo; Jacobsen, Ole Stig;

    2009-01-01

    denitrification process with pyrite as the primary electron donor. The process demonstrates a temperature dependency (Q10) of 1.8 and could be completely inhibited by addition of a bactericide (NaN3). Experimentally determined denitrification rates show that more than 50% of the observed nitrate reduction can...

  10. Antipneumococcal Activity of Dalbavancin Compared to Other Agents

    OpenAIRE

    Lin, Gengrong; Smith, Kathy; Ednie, Lois M.; Appelbaum, Peter C.

    2005-01-01

    Against 307 pneumococci of various resistotypes, dalbavancin MICs were 0.008 to 0.125 μg/ml. All strains were susceptible to vancomycin, teicoplanin, linezolid, and quinupristin-dalfopristin. Dalbavancin at 2× MIC was bactericidal against all 10 pneumococci tested after 24 h. Vancomycin and teicoplanin killed 10 and 8 strains, respectively, at 2× MIC after 24 h.

  11. Activity of sparfloxacin on Staphylococcus epidermidis attached to plastic catheters.

    Science.gov (United States)

    Pascual, A; García, I; Ramirez de Arellano, E; Perea, E J

    1995-08-01

    The activity of sparfloxacin on Staphylococcus epidermidis biofilms on different plastic catheters was evaluated. Sparfloxacin showed high bactericidal activity against S. epidermidis biofilms on Vialon and polyvinylchloride catheters. The combination of sparfloxacin with amikacin or rifampicin significantly increased its activity against bacterial biofilms on polyurethane and Teflon catheters. PMID:8522473

  12. Eugenol alters the integrity of cell membrane and acts against the nosocomial pathogen Proteus mirabilis.

    Science.gov (United States)

    Devi, K Pandima; Sakthivel, R; Nisha, S Arif; Suganthy, N; Pandian, S Karutha

    2013-03-01

    Eugenol, a member of the phenylpropanoids class of chemical compounds, is a clear to pale yellow oily liquid extracted from certain essential oils especially from clove oil, nutmeg, cinnamon, and bay leaf. The antibacterial activity of eugenol and its mechanism of bactericidal action against Proteus mirabilis were evaluated. Treatment with eugenol at their minimum inhibitory concentration [0.125 % (v/v)] and minimum bactericidal concentration [0.25 % (v/v)] reduced the viability and resulted in complete inhibition of P. mirabilis. A strong bactericidal effect on P. mirabilis was also evident, as eugenol inactivated the bacterial population within 30 min exposure. Chemo-attractant property and the observance of highest antibacterial activity at alkaline pH suggest that eugenol can work more effectively when given in vivo. Eugenol inhibits the virulence factors produced by P. mirabilis as observed by swimming motility, swarming behavior and urease activity. It interacts with cellular membrane of P. mirabilis and makes it highly permeable, forming nonspecific pores on plasma membrane, which in turn directs the release of 260 nm absorbing materials and uptake of more crystal violet from the medium into the cells. SDS-polyacrylamide gel, scanning electron microscopy and Fourier transform infrared analysis further proves the disruptive action of eugenol on the plasma membrane of P. mirabilis. The findings reveal that eugenol shows an excellent bactericidal activity against P. mirabilis by altering the integrity of cell membrane. PMID:23444040

  13. Antimicrobial activities of red wine-based formulations containing plant extracts against Escherichia coli O157:H7 and Salmonella enterica serovar Hadar

    Science.gov (United States)

    We evaluated the bactericidal activities of red wine and red wine solutions containing a commercial olive extract called Hydrox-12, oregano oil, or a mixture of both in red wine against the following foodborne pathogens: Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes, and Stap...

  14. Adaptation of the food-borne pathogen Bacillus cereus to carvacrol

    NARCIS (Netherlands)

    Ultee, A.; Kets, E.P.W.; Alberda, M.; Hoekstra, F.A.; Smid, E.J.

    2000-01-01

    Carvacrol, a natural antimicrobial compound present in the essential oil fraction of oregano and thyme, is bactericidal towards Bacillus cereus. A decrease of the sensitivity of B. cereus towards carvacrol was observed after growth in the presence of non-lethal carvacrol concentrations. A decrease o

  15. Activity of and Resistance to Moxifloxacin in Staphylococcus aureus

    OpenAIRE

    Ince, Dilek; Zhang, Xiamei; Hooper, David C.

    2003-01-01

    Moxifloxacin has enhanced potency against Staphylococcus aureus, lower propensity to select for resistant mutants, and higher bactericidal activity against highly resistant strains than ciprofloxacin. Despite similar activity against purified S. aureus topoisomerase IV and DNA gyrase, it selects for topoisomerase IV mutants, making topoisomerase IV the preferred target in vivo.

  16. CFD Simulation of the distribution of ClO2 in fresh produce to improve safety

    Science.gov (United States)

    The shelf life of fresh-cut produce may be prolonged with the injection of bactericide gases like chlorine dioxide (ClO2). A comparative study has been conducted by modeling the injection of three different gases, CO2, ClO2 and N2 inside a PET clamshell containers commonly use to package fresh produ...

  17. Antibacterial and Antibiofilm Effect of Low Viscosity Chitosan against Staphylococcus epidermidis

    Directory of Open Access Journals (Sweden)

    Inger Sofie Dragland

    2016-01-01

    Full Text Available Aim. The aim of this study was to investigate the antibacterial and antibiofilm properties of low viscosity chitosan on S. epidermidis growth and biofilm formation. Methods and Results. The antibacterial and antibiofilm properties were investigated, during both planktonic growth and biofilm formation. This was performed using different concentrations in media and by coating on polystyrene surfaces. In addition, the bactericidal effect was investigated using a modified direct contact test. The results showed that low viscosity chitosan in media had both a bacteriostatic and bactericidal effect on planktonic growth and biofilm formation of S. epidermidis in a concentration dependent manner. Polystyrene discs coated with chitosan reduced both early biofilm formation (6 h and late biofilm formation (18 h, as confirmed by scanning electron microscopy. The modified direct contact test showed a bactericidal effect. Conclusion. This study demonstrated that low viscosity chitosan has a bacteriostatic and bactericidal activity against S. epidermidis and that the activity is dependent on the amount of chitosan added. In addition, low viscosity chitosan reduced biofilm formation both when added to media and when coated on polystyrene surfaces. Significance and Impact of Study. Low viscosity chitosan could be a contribution to new treatment approaches of biofilm-related infections of S. epidermidis.

  18. Antimicrobial Susceptibility of Escherichia coli Strains Isolated from Alouatta spp. Feces to Essential Oils

    OpenAIRE

    Valéria Maria Lara; Adriano Bonfim Carregaro; Deise Flores Santurio; Mariangela Facco de Sá; Janio Moraes Santurio; Sydney Hartz Alves

    2016-01-01

    This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano), Origanum vulgaris (oregano), Thymus vulgaris (thyme), Rosmarinus officinalis (rosemary), Cymbopogon nardus (citronella), Cymbopogon citratus (lemongrass), and Eucalyptus citriodora (eucalyptus) against Escherichia coli (n = 22) strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each ...

  19. Transformation of serum-susceptible Escherichia coli O111 with p16Slux plasmid to allow for real-time monitoring of complement-based inactivation of bacterial growth in bovine milk.

    Science.gov (United States)

    Maye, S; Stanton, C; Fitzgerald, G F; Kelly, P M

    2016-01-01

    Complement activity has only recently been characterized in raw bovine milk. However, the activity of this component of the innate immune system was found to diminish as milk was subjected to heat or partitioning during cream separation. Detection of complement in milk relies on a bactericidal assay. This assay exploits the specific growth susceptibility of Escherichia coli O111 to the presence of complement. Practical application of the assay was demonstrated when a reduction in complement activity was recorded in the case of pasteurized and reduced-fat milks. This presented an opportunity to improve the functionality of the bactericidal assay by incorporating bioluminescence capability into the target organism. Following some adaptation, the strain was transformed by correctly integrating the p16Slux plasmid. Growth properties of the transformed strain of E. coli O111 were unaffected by the modification. The efficacy of the strain adaptation was correlated using the LINEST function analysis [r=0.966; standard error of prediction (SEy)=0.957] bioluminescence with that of bactericidal assay total plate counts within the range of 7.5 to 9.2 log cfu/mL using a combination of raw and processed milk samples. Importantly, the transformed E. coli O111 p16Slux strain could be identified in milk and broth samples using bioluminescence measurement, thus enabling the bactericidal assay-viability test to be monitored in real time throughout incubation.

  20. Laser ablation of lysozyme with UV, visible and infrared femto- and nanosecond pulses

    DEFF Research Database (Denmark)

    Schou, Jørgen; Canulescu, Stela; Matei, Andreea;

    Lysozyme is an interesting molecule for laser ablation of organic materials, because the ablation has been comprehensively studied, it is a medium heavy molecule with a mass of 14305 Da, which can be detected by standard techniques, and because it is used as a bactericidal protein in the food ind...