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Sample records for high bactericidal activity

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

    Science.gov (United States)

    Saul, Allan; Rondini, Simona

    2017-01-01

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

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

    OpenAIRE

    1997-01-01

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

  3. 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.

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

    Science.gov (United States)

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

    2017-02-01

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

  5. Bactericidal activity of partially oxidized nanodiamonds.

    Science.gov (United States)

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

    2014-06-24

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

  6. Bactericidal activity of titanium dioxide ultraviolet-induced films

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-01

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

  7. 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.

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

    Science.gov (United States)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  10. 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.

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2009-12-01

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

  13. TLR signaling augments macrophage bactericidal activity through mitochondrial ROS

    OpenAIRE

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

    2011-01-01

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

  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. 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

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

    Science.gov (United States)

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

    1996-06-01

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

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

    Science.gov (United States)

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

    2011-10-15

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

  18. 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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2001-12-01

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

  1. The bactericidal activity of glutaraldehyde-impregnated polyurethane.

    Science.gov (United States)

    Sehmi, Sandeep K; Allan, Elaine; MacRobert, Alexander J; Parkin, Ivan

    2016-10-01

    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-coated polyurethane"). The antibacterial activity of glutaraldehyde-impregnated and glutaraldehyde-coated polyurethane samples was tested against Escherichia coli and Staphylococcus aureus. Glutaraldehyde-impregnated polyurethane resulted in a 99.9% reduction in the numbers of E. coli within 2 h and a similar reduction of S. aureus within 1 h, whereas only a minimal reduction in bacterial numbers was observed when the biocide was bound to the polymer surface. After 15 days, however, the bactericidal activity of the impregnated material was substantially reduced presumably due to polymerization of glutaraldehyde. Thus, although glutaraldehyde retains antibacterial activity when impregnated into polyurethane, activity is not maintained for extended periods of time. Future work should examine the potential of chemical modification of glutaraldehyde and/or polyurethane to improve the useful lifespan of this novel antibacterial polymer. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

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

    Science.gov (United States)

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

    1975-11-21

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

  3. 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.

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

    Science.gov (United States)

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

    2010-10-01

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

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

    Science.gov (United States)

    Taylor, Matthew; McCollister, Bruce; Park, Daewon

    2016-03-01

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

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

    OpenAIRE

    Gjorgjeska, Biljana

    2011-01-01

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

  7. [Bactericidal Activity of Constructed Recombinant Fusion Protein Pheromonicin-CT].

    Science.gov (United States)

    Yu, Huan; Zuo, Yue-wen; Qiu, Xiao-qing

    2015-11-01

    To construct engineering peptide pheromonicin-Clostrzaum tretant krn-ui), and to test its bactericidal activity. We amplified the gene of variable regions from hybridoma cells which secreted monoclonal antibody (mAb) against antigen in the membrane of Clostridium tetani and linked the small antibody mimetic to the channel-forming domain of colicin Ia to create Ph-CT. The Ph-CT was purified by CM sepharose ion-exchange column. Its in vitro antibacterial activity was evaluated by colony culture with different doses of Ph-CT (final concentration 2, 4, 8, and 16 microg/mL,respectively). Then we inoculated culture medium with CT strains and different doses of Ph-CT (final concentration of 4 and 16 microg/mL). The in vivo antibacterial activity of Ph-CT was evaluated by cumulative survival of mice. After 16 hours' anaerobic culture, the mice was treated with filtered CT medium or CT medium. We constructed Ph-CT successfully. CT colonies appeared in the CT medium treated with Ph-CT (2, 4 microg/mL), while no colony appeared in the CT medium treated with Ph-CT (8, 16 microg/mL). All mice survived when they were injected with filtered CT medium treated with Ph-CT (4, 16 microg/mL) and CT medium treated with Ph-CT (16 microg/mL). Three (50%) mice survived when they were injected with CT medium treated with Ph-CT (4 microg/mL). All mice in the control groups died after CT infections. Ph-CT may be of value as antibiotics against Clostridium tetani.

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

    Science.gov (United States)

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

    2017-01-01

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

  9. 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.

  10. 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.

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

    Science.gov (United States)

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

    2013-02-01

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

  12. Serum and blister fluid pharmacokinetics and bactericidal activities of ampicillin-sulbactam, cefotetan, cefoxitin, ceftizoxime, and ticarcillin-clavulanate.

    Science.gov (United States)

    Jaresko, G S; Barriere, S L; Johnson, B L

    1992-01-01

    Ampicillin-sulbactam, ticarcillin-clavulanate, cefoxitin, cefotetan, and ceftizoxime are promoted for the treatment of mixed aerobic-anaerobic bacterial infections. Their activities have been compared in vitro but not in vivo. In order to assess the in vivo activities of these agents in serum and interstitial fluid, we administered single, intravenous doses of these antimicrobial agents to healthy subjects. Concentrations of the antimicrobial agents in serum and suction-induced blister fluid and bactericidal activity were measured by high-pressure liquid chromatography and the standard methodology of the National Committee for Clinical Laboratory Standards, respectively. The organisms used for bactericidal activity tests were one isolate each of Staphylococcus aureus, Klebsiella pneumoniae, and Bacteroides fragilis. Pharmacokinetic parameters in serum and blister fluid were similar to those derived in other investigations. Of note were the high and prolonged concentrations of ticarcillin and cefotetan in blister fluid, despite high-level serum protein binding. The bactericidal activities in serum and blister fluid reflected the relative in vitro activities and kinetic dispositions of the various antimicrobial agents except for the bactericidal activity of cefotetan, which was substantially lower in blister fluid than serum, despite a blister fluid:serum area under the concentration-time curve ratio of 1.5. Similarly, the activity of ticarcillin-clavulanate in blister fluid was also substantially less than would have been predicted by the blister fluid:serum ratio of the area under the concentration-time curve of 1.1, possibly because of the low concentrations of clavulanate in blister fluid. The rankings of the in vivo bactericidal activities of the five drugs were as follows: for S. aureus, ampicillin-sulbactam > ticarcillin-clavulanate > ceftizoxime > cefoxitin > cefotetan; for K. pneumoniae, ceftizoxime > cefotetan > ampicillin-sulbactam = ticarcillin

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

    Science.gov (United States)

    Dailloux, M; Villemain, P

    1992-05-01

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

  14. 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.

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

    Science.gov (United States)

    Xiao, Gang; Zhang, Xiaodong; Zhao, Yan; Su, Haijia; Tan, Tianwei

    2014-02-01

    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.

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2007-08-01

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

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

    Science.gov (United States)

    Bramley, A J; Hogben, E M

    1983-02-01

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

  19. 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.

  20. 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

  1. 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.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  3. Synergistic bactericidal activity of chlorhexidine-loaded, silver-decorated mesoporous silica nanoparticles.

    Science.gov (United States)

    Lu, Meng-Meng; Wang, Qiu-Jing; Chang, Zhi-Min; Wang, Zheng; Zheng, Xiao; Shao, Dan; Dong, Wen-Fei; Zhou, Yan-Min

    2017-01-01

    Combination of chlorhexidine (CHX) and silver ions could engender synergistic bactericidal effect and improve the bactericidal efficacy. It is highly desired to develop an efficient carrier for the antiseptics codelivery targeting infection foci with acidic microenvironment. In this work, monodisperse mesoporous silica nanoparticle (MSN) nanospheres were successfully developed as an ideal carrier for CHX and nanosilver codelivery through a facile and environmentally friendly method. The CHX-loaded, silver-decorated mesoporous silica nanoparticles (Ag-MSNs@CHX) exhibited a pH-responsive release manner of CHX and silver ions simultaneously, leading to synergistically antibacterial effect against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. Moreover, the effective antibacterial concentration of Ag-MSNs@CHX showed less cytotoxicity on normal cells. Given their synergistically bactericidal ability and good biocompatibility, these nanoantiseptics might have effective and broad clinical applications for bacterial infections.

  4. Bactericidal Activity of Octenidine to Various Genospecies of Borrelia burgdorferi, Sensu Lato Spirochetes in Vitro and in Vivo.

    Science.gov (United States)

    Tylewska-Wierzbanowska, Stanisława; Rogulska, Urszula; Lewandowska, Grażyna; Chmielewski, Tomasz

    2017-07-06

    The aim of our studies was to invent a reliable method for detection of the bactericidal activity of disinfectants against Borrelia burgdorferi in suspension (in vitro) and in cell line cultures (in vivo). In the suspension method, 0.01% octenidine at 20°C and 35°C was bactericidal to Borrelia afzeli; Borrelia garini, B. burgdorferi sensu stricto after 5 minutes treatment. Increase of the temperature to 35°C speed up the bactericidal effect to 1 minute. The bactericidal action of octenidine towards B. burgdorferi spirochetes growing in fibroblasts was less effective and needed a longer time to kill them than in the suspension.

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

    OpenAIRE

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

    1980-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-06-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  8. 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...

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  11. 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.

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

    Science.gov (United States)

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

    2016-03-28

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

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

    Science.gov (United States)

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

    1980-07-01

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

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

    Science.gov (United States)

    Das, Deeplina; Goyal, Arun

    2013-09-01

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

  15. Observation of Serum Bactericidal Activity of Brucella abortus RB51 OMPs Combined with Brucella abortus RB51 Live Vaccine

    Directory of Open Access Journals (Sweden)

    Fahime Gholizadeh

    2013-06-01

    Full Text Available Background & objectives: vaccination is vital against brucellosis. Although current vaccines have low efficiency, some cell wall compartments such as Outer Membrane Proteins could be used as an immunogenic candidate in vaccine development. By this mean, our aim in this study was to evaluate the humoral immunity of the combination of Brucella abortus RB51 OMPs with the Brucella abortus RB51 live attenuated vaccine, by Serum Bactericidal Acitivity test. Materials and Methods: In this project, first Brucella abortus RB51 was cultivated in brucella agar. The OMPs were extracted by Sodium N-Lauryl Sarcosinate method, then added to the RB51 live attenuated vaccine. Immunization was done by injection of the vaccine to mice and rabbits. The blood was drawn on days 0, 15,30, and 45 from the rabbits and the sera were seperated. Brucella abortus 544 was also injected as challenge. Spleen colony count was also performed. Results: The data from Serum Bactericidal Assay has showed, there was a very high Humoral immunity and response as a bactericidal titre of the serum against Rb51 Live vaccine. There was a significant decrease of colonies in the group vaccinated with the combined vaccine in the Spleen colony count test. Statistical analysis of groups variances showed a significant difference between groups (P<0.05.Conclusions: The Serum Bactericidal Assay results showed despite previous studies, both the combine and live vaccine are capable to stimulate the Humoral immunity. greater activity of combined vaccine to boost the humoral activity might be due to the synergistic effect of this vaccine.

  16. Evaluation of the bactericidal activity of Telavancin against Staphylococcus aureus using revised testing guidelines.

    Science.gov (United States)

    Sweeney, Debora; Shinabarger, Dean L; Smart, Jennifer I; Bruss, Jon; Pillar, Chris M

    2017-09-01

    The in vitro broth microdilution testing method for telavancin, a lipoglycopeptide active against S. aureus, was revised in 2014 to include polysorbate-80 in the test media. This study evaluates the bactericidal activity of telavancin against S. aureus in media containing polysorbate-80 by in vitro time-kill analysis alongside relevant comparators. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    1987-03-01

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

  18. Bactericidal activity of soymilk fermentation broth by in vitro and animal models.

    Science.gov (United States)

    Chin, Yi-Ping; Tsui, Ko-Chung; Chen, Mei-Chieh; Wang, Cheng-Yi; Yang, Chin-Yuh; Lin, Yuh-Ling

    2012-06-01

    Soybean fermentation broth (SFB) exhibits potent antibacterial activity against different species of bacteria in in vitro assays and animal models. Four isoflavone compounds-daidzin, genistin, genistein, and daidzein-of SFB were analyzed and quantified by high-performance liquid chromatography. In the in vitro test, daidzin and daidzein had more potent antibacterial activity than genistin. The minimum inhibition concentration values for these bacteria of SFB ranged from 1.25% to 5%, and the minimum bactericidal concentration values of strains ranged from 2.5% to 10%, depending on the species or strain. Vancomycin-resistant Entercoccus faecalis (VRE) strains were also tested for susceptibility to SFB in two species of animal model: the Sprague-Dawley rat and the BALB/c mouse. SFB-fed Sprague-Dawley rats showed excellent elimination efficiency against VRE, close to 99% compared with the phosphate-buffered saline-fed control group. In the BALB/c mouse model, SFB antibacterial activity was 65-80% against VRE compared with the control. In conclusion, SFB contains natural antibacterial substances such as daidzin, genistin, and daidzein that inhibit bacterial growth.

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

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    MSc Diogo José Horst

    2016-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

    LIU Xinhua; WANG Shifan; SONG Baoan

    2007-01-01

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

  1. Bactericidal activity of herbal volatile oil extracts against multidrug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Intorasoot, Amornrat; Chornchoem, Piyaorn; Sookkhee, Siriwoot; Intorasoot, Sorasak

    2017-01-01

    The aim of the study is to investigate the antibacterial activity of 10 volatile oils extracted from medicinal plants, including galangal (Alpinia galanga Linn.), ginger (Zingiber officinale), plai (Zingiber cassumunar Roxb.), lime (Citrus aurantifolia), kaffir lime (Citrus hystrix DC.), sweet basil (Ocimum basilicum Linn.), tree basil (Ocimum gratissimum), lemongrass (Cymbopogon citratus DC.), clove (Syzygium aromaticum), and cinnamon (Cinnamomum verum) against four standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and 30 clinical isolates of multidrug-resistant A. baumannii (MDR-A. baumannii). Agar diffusion, minimum inhibitory concentration, and minimum bactericidal concentration (MBC) were employed for the determination of bactericidal activity of water distilled medicinal plants. Tea tree oil (Melaleuca alternifolia) was used as positive control in this study. The results indicated the volatile oil extracted from cinnamon exhibited potent antibacterial activity against the most common human pathogens, S. aureus, E. coli, P. aeruginosa, and A. baumannii. Most of volatile oil extracts were less effective against non-fermentative bacteria, P. aeruginosa. In addition, volatile oil extracted from cinnamon, clove, and tree basil possessed potent bactericidal activity against MDR-A. baumannii with MBC90 of 0.5, 1, and 2 mg/mL, respectively. The volatile oil extracts would be useful as alternative natural product for the treatment of the most common human pathogens and MDR-A. baumannii infections.

  2. 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.

  3. 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.

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

    Science.gov (United States)

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

    2017-03-01

    Propolis has been used as a medicinal agent for centuries. The chemical composition of four propolis samples collected from four locations of the Sétif region, Algeria, using gas chromatography-mass spectrometry was determined. More than 20 compounds and from 30 to 35 compounds were identified in the aqueous and ethanolic extracts, respectively. Furthermore, the antimicrobial activity of the propolis extracts against two marine pathogenic bacteria was evaluated. Finally, the in vitro effects of propolis on gilthead seabream (Sparus aurata L.) leucocyte activities were measured. The bactericidal activity of ethanolic extracts was very high against Shewanella putrefaciens, average against Photobacterium damselae and very low against Vibrio harveyi. The lowest bactericidal activity was always that found for the aqueous extracts. When the viability of gilthead seabream head-kidney leucocytes was measured after 30 min' incubation with the different extracts, both the ethanolic and aqueous extracts of one of the propolis samples (from Babor) and the aqueous extract of another (from Ain-Abbassa) provoked a significant decrease in cell viability when used at concentrations of 100 and 200 μg ml(-1). Furthermore, significant inhibitory effects were recorded on leucocyte respiratory burst activity when isolated leucocytes where preincubated with the extracts. This effect was dose-dependent in all cases except when extracts from a third propolis sample (from Boutaleb) were used. Our findings suggest that some of Algerian propolis extracts have bactericidal activity against important bacterial pathogens in seabream and significantly modulate in vitro leucocyte activities, confirming their potential as a source of new natural biocides and/or immunomodulators in aquaculture practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Hakim, J

    1980-09-13

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

  6. Superhydrophobic and White Light-Activated Bactericidal Surface through a Simple Coating.

    Science.gov (United States)

    Hwang, Gi Byoung; Patir, Adnan; Allan, Elaine; Nair, Sean P; Parkin, Ivan P

    2017-08-30

    Bacterial adhesion and proliferation on surfaces are a challenge in medical and industrial fields. Here, a simple one-step technique is reported to fabricate self-cleaning and bactericidal surfaces. White, blue, and violet paints were produced using titanium dioxide nanoparticles, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, crystal violet, toluidine Blue O, and ethanol solution. All of the painted surfaces showed superhydrophobicity in air, and even after hexadecane oil contamination, they retained water repellency and self-cleaning properties. In an assay of bacterial adhesion, significant reductions (>99.8%) in the number of adherent bacteria were observed for all the painted surfaces. In bactericidal tests, the painted surfaces not only demonstrated bactericidal activity against Staphylococcus aureus and Escherichia coli in the dark but also induced very potent photosensitization (>4.4 log reduction in the number of viable bacteria on the violet painted surface) under white light illumination. The technique that we developed here is general and can be used on a wide range of substrates such as paper, glass, polymers, and others.

  7. 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

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

    Science.gov (United States)

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

    2005-08-01

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

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

    Science.gov (United States)

    Peters, V B; Rubin, L G

    1992-08-01

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

  10. 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.

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

    Science.gov (United States)

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

    1990-12-01

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

  12. Copper and quaternary ammonium cations exert synergistic bactericidal and antibiofilm activity against Pseudomonas aeruginosa.

    Science.gov (United States)

    Harrison, Joe J; Turner, Raymond J; Joo, Daniel A; Stan, Michelle A; Chan, Catherine S; Allan, Nick D; Vrionis, Helen A; Olson, Merle E; Ceri, Howard

    2008-08-01

    Biofilms are slimy aggregates of microbes that are likely responsible for many chronic infections as well as for contamination of clinical and industrial environments. Pseudomonas aeruginosa is a prevalent hospital pathogen that is well known for its ability to form biofilms that are recalcitrant to many different antimicrobial treatments. We have devised a high-throughput method for testing combinations of antimicrobials for synergistic activity against biofilms, including those formed by P. aeruginosa. This approach was used to look for changes in biofilm susceptibility to various biocides when these agents were combined with metal ions. This process identified that Cu(2+) works synergistically with quaternary ammonium compounds (QACs; specifically benzalkonium chloride, cetalkonium chloride, cetylpyridinium chloride, myristalkonium chloride, and Polycide) to kill P. aeruginosa biofilms. In some cases, adding Cu(2+) to QACs resulted in a 128-fold decrease in the biofilm minimum bactericidal concentration compared to that for single-agent treatments. In combination, these agents retained broad-spectrum antimicrobial activity that also eradicated biofilms of Escherichia coli, Staphylococcus aureus, Salmonella enterica serovar Cholerasuis, and Pseudomonas fluorescens. To investigate the mechanism of action, isothermal titration calorimetry was used to show that Cu(2+) and QACs do not interact in aqueous solutions, suggesting that each agent exerts microbiological toxicity through independent biochemical routes. Additionally, Cu(2+) and QACs, both alone and in combination, reduced the activity of nitrate reductases, which are enzymes that are important for normal biofilm growth. Collectively, the results of this study indicate that Cu(2+) and QACs are effective combinations of antimicrobials that may be used to kill bacterial biofilms.

  13. Copper and Quaternary Ammonium Cations Exert Synergistic Bactericidal and Antibiofilm Activity against Pseudomonas aeruginosa▿

    Science.gov (United States)

    Harrison, Joe J.; Turner, Raymond J.; Joo, Daniel A.; Stan, Michelle A.; Chan, Catherine S.; Allan, Nick D.; Vrionis, Helen A.; Olson, Merle E.; Ceri, Howard

    2008-01-01

    Biofilms are slimy aggregates of microbes that are likely responsible for many chronic infections as well as for contamination of clinical and industrial environments. Pseudomonas aeruginosa is a prevalent hospital pathogen that is well known for its ability to form biofilms that are recalcitrant to many different antimicrobial treatments. We have devised a high-throughput method for testing combinations of antimicrobials for synergistic activity against biofilms, including those formed by P. aeruginosa. This approach was used to look for changes in biofilm susceptibility to various biocides when these agents were combined with metal ions. This process identified that Cu2+ works synergistically with quaternary ammonium compounds (QACs; specifically benzalkonium chloride, cetalkonium chloride, cetylpyridinium chloride, myristalkonium chloride, and Polycide) to kill P. aeruginosa biofilms. In some cases, adding Cu2+ to QACs resulted in a 128-fold decrease in the biofilm minimum bactericidal concentration compared to that for single-agent treatments. In combination, these agents retained broad-spectrum antimicrobial activity that also eradicated biofilms of Escherichia coli, Staphylococcus aureus, Salmonella enterica serovar Cholerasuis, and Pseudomonas fluorescens. To investigate the mechanism of action, isothermal titration calorimetry was used to show that Cu2+ and QACs do not interact in aqueous solutions, suggesting that each agent exerts microbiological toxicity through independent biochemical routes. Additionally, Cu2+ and QACs, both alone and in combination, reduced the activity of nitrate reductases, which are enzymes that are important for normal biofilm growth. Collectively, the results of this study indicate that Cu2+ and QACs are effective combinations of antimicrobials that may be used to kill bacterial biofilms. PMID:18519726

  14. Prevalence, antigenic specificity, and bactericidal activity of poultry anti-Campylobacter maternal antibodies.

    Science.gov (United States)

    Sahin, O; Zhang, Q; Meitzler, J C; Harr, B S; Morishita, T Y; Mohan, R

    2001-09-01

    Poultry are considered the major reservoir for Campylobacter jejuni, a leading bacterial cause of human food-borne diarrhea. To understand the ecology of C. jejuni and develop strategies to control C. jejuni infection in the animal reservoir, we initiated studies to examine the potential role of anti-Campylobacter maternal antibodies in protecting young broiler chickens from infection by C. jejuni. Using an enzyme-linked immunosorbent assay (ELISA), the prevalence of anti-C. jejuni antibodies in breeder chickens, egg yolks, and broilers from multiple flocks of different farms were examined. High levels of antibodies to the organism were detected in serum samples of breeder chickens and in egg yolk contents. To determine the dynamics of anti-Campylobacter maternal antibody transferred from yolks to hatchlings, serum samples collected from five broiler flocks at weekly intervals from 1 to 28 or 42 days of age were also examined by ELISA. Sera from the 1-day and 7-day-old chicks showed high titers of antibodies to C. jejuni. Thereafter, antibody titers decreased substantially and were not detected during the third and fourth weeks of age. The disappearance of anti-Campylobacter maternal antibodies during 3 to 4 weeks of age coincides with the appearance of C. jejuni infections observed in many broiler chicken flocks. As shown by immunoblotting, the maternally derived antibodies recognized multiple membrane proteins of C. jejuni ranging from 19 to 107 kDa. Moreover, in vitro serum bactericidal assays showed that anti-Campylobacter maternal antibodies were active in antibody-dependent complement-mediated killing of C. jejuni. Together, these results highlight the widespread presence of functional anti-Campylobacter antibodies in the poultry production system and provide a strong rationale for further investigation of the potential role of anti-C. jejuni maternal antibodies in protecting young chickens from infection by C. jejuni.

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

    Science.gov (United States)

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

    2011-05-27

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

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

    Science.gov (United States)

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

    2007-10-15

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

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

    Science.gov (United States)

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

    2017-04-01

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

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

    Science.gov (United States)

    Kampf, Günter; Hollingsworth, Angela

    2008-01-22

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

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

    Directory of Open Access Journals (Sweden)

    Kampf Günter

    2008-01-01

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

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

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    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.

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

    Science.gov (United States)

    Boisivon, A; Guiomar, C; Carbon, C

    1990-03-01

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

  2. Bactericidal activity of ethanolic extracts of propolis against Staphylococcus aureus isolated from mastitic cows.

    Science.gov (United States)

    Santana, Henrique Freitas; Barbosa, Ana Andréa Teixeira; Ferreira, Sukarno Olavo; Mantovani, Hilário Cuquetto

    2012-02-01

    Staphylococcus aureus is an important pathogen for both humans and animals, and it has been an ubiquitous etiological agent of bovine mastitis in dairy farms worldwide. Elimination of S. aureus with classic antibiotics is difficult, and the current study aimed to evaluate the efficacy of ethanolic extracts of propolis (EEP) against S. aureus cultivated in complex media or milk. EEP (0-0.5 mg ml(-1)) decreased growth of S. aureus in BHI media and 1 mg ml(-1) was bactericidal against washed cell suspensions (10(7) CFU ml(-1)). Propolis extracts also killed S. aureus cells resuspended in milk, but the bactericidal dose was at least 20-fold greater. Cultures that were transferred for at least 60 generations with sub-lethal doses of propolis did not change much their sensibility to EEP. Atomic force microscopy images revealed changes in morphology and cell size of S. aureus cells exposed to EEP (0.5 mg ml(-1)). Our results indicate that propolis extracts might be effective against mastitis-causing S. aureus strains in vivo, but milk constituents affect the inhibitory activity of propolis. Considering that propolis-resistance appears to be a phenotype not easily selected, the use of EEP combined or not with other antimicrobial agents might be useful for mastitis control in vivo.

  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. Smart Biointerface with Photoswitched Functions between Bactericidal Activity and Bacteria-Releasing Ability.

    Science.gov (United States)

    Wei, Ting; Zhan, Wenjun; Yu, Qian; Chen, Hong

    2017-08-09

    Smart biointerfaces with capability to regulate cell-surface interactions in response to external stimuli are of great interest for both fundamental research and practical applications. Smart surfaces with "ON/OFF" switchability for a single function such as cell attachment/detachment are well-known and useful, but the ability to switch between two different functions may be seen as the next level of "smart". In this work reported, a smart supramolecular surface capable of switching functions reversibly between bactericidal activity and bacteria-releasing ability in response to UV-visible light is developed. This platform is composed of surface-containing azobenzene (Azo) groups and a biocidal β-cyclodextrin derivative conjugated with seven quaternary ammonium salt groups (CD-QAS). The surface-immobilized Azo groups in trans form can specially incorporate CD-QAS to achieve a strongly bactericidal surface that kill more than 90% attached bacteria. On irradiation with UV light, the Azo groups switch to cis form, resulting in the dissociation of the Azo/CD-QAS inclusion complex and release of dead bacteria from the surface. After the kill-and-release cycle, the surface can be easily regenerated for reuse by irradiation with visible light and reincorporation of fresh CD-QAS. The use of supramolecular chemistry represents a promising approach to the realization of smart, multifunctional surfaces, and has the potential to be applied to diverse materials and devices in the biomedical field.

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

    Directory of Open Access Journals (Sweden)

    Clifford E. Starliper

    2015-01-01

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

  6. Synthesis of silver nanoparticles by endosymbiont Pseudomonas fluorescens CA 417 and their bactericidal activity.

    Science.gov (United States)

    Syed, Baker; M N, Nagendra Prasad; B L, Dhananjaya; K, Mohan Kumar; S, Yallappa; S, Satish

    2016-12-01

    The present study emphasizes on biogenic synthesis of silver nanoparticles and their bactericidal activity against human and phytopathogens. Nanoparticle synthesis was performed using endosymbiont Pseudomonas fluorescens CA 417 inhabiting Coffea arabica L. Synthesized nanoparticles were characterized using hyphenated spectroscopic techniques such as UV-vis spectroscopy which revealed maximum absorption 425nm. Fourier transform infrared spectroscopy (FTIR) analysis revealed the possible functional groups mediating and stabilizing silver nanoparticles with predominant peaks occurring at 3346 corresponding to hydroxyl group, 1635 corresponding carbonyl group and 680 to aromatic group. X-ray diffraction (XRD) analysis revealed the Bragg's diffraction pattern with distinct peaks at 38° 44°, 64° and 78° revealing the face-centered cubic (fcc) metallic crystal corresponding to the (111), (200), (220) and (311) facets of the crystal planes at 2θ angle. The energy dispersive X-ray spectroscopy (EDS) analysis revealed presence of high intense absorption peak at 3keV is a typical characteristic of nano-crystalline silver which confirmed the presence of elemental silver. TEM analysis revealed the size of the nanoparticles to be in the range 5-50nm with polydisperse nature of synthesized nanoparticles bearing myriad shapes. The particle size determined by Dynamic light scattering (DLS) method revealed average size to be 20.66nm. The synthesized silver nanoparticles exhibited significant antibacterial activity against panel of test pathogens. The results showed Klebsiella pneumoniae (MTCC 7407) and Xanthomonas campestris to be more sensitive among the test human pathogen and phyto-pathogen respectively. The study also reports synergistic effect of silver nanoparticles in combination with kanamycin which displayed increased fold activity up to 58.3% against Klebsiella pneumoniae (MTCC 7407). The results of the present investigation are promising enough and attribute towards

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

    OpenAIRE

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

    1990-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Paola Del Porto

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

  9. 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.

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

    Science.gov (United States)

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

    2017-02-15

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

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

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    Deepak V Almeida

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

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

    Science.gov (United States)

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

    1986-02-01

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

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

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    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.

  14. 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.

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2002-11-01

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

  18. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2012-06-01

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

  1. 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.

  2. Evaluation of bactericidal activity of Hannon honey on slowly growing bacteria in the chemostat

    Directory of Open Access Journals (Sweden)

    Sufya N

    2014-10-01

    Full Text Available Najib Sufya,1 Noora Matar,1 Rawanda Kaddura,1 Abdulaziz Zorgani2 1Department of Microbiology and Immunology, Faculty of Pharmacy, 2Department of Microbiology and Immunology, Faculty of Medicine, University of Tripoli, Tripoli, Libya Abstract: There is renewed interest in the therapeutic use of honey, including use in the treatment of infected wounds and burn patients. In this study, we have assessed the antibacterial activity of Libyan floral Hannon honey on Escherichia coli and Staphylococcus aureus, both known to infect wounds. The effects of four concentrations (5%–30% of honey were compared with that of four antibiotics (ampicillin, tetracycline, polymyxin, and ciprofloxacin on the growth of these bacteria at early log, mid log, and late log phases. It has been shown that E. coli and S. aureus are to some degree susceptible during mid log phase compared with late log phase, demonstrated by their complete resistance to antibiotics. Chemostat culture was used to investigate the effect of honey on E. coli grown at a steady state with specific growth rates between 0.1 to 0.5 hour-1. The rate of killing was distinctively clear during the two stages of growth monitored: there was a relatively moderate reduction at the slow growth phase (0.1 to 0.3 hour-1, while a dramatic reduction was obtained at the fast growth phase (0.3 to 0.5 hour-1, reaching a complete reduction at 0.5 hour-1. These results complement data using the cup-cut technique. The antibacterial effect of honey was concentration and time dependent, the bactericidal effect was indeed observed at low concentrations, it demonstrates that the honey has more impact on slow growing bacteria than antibiotics have. We suggest that more reduction could be achieved at higher concentrations of honey. These results may have important clinical implications, such as for the management of wound and burn patients. Keywords: antibiotic, killing, Libya, Escherichia coli, Staphylococcus aureus 

  3. Studies of bactericidal activity to Escherichia coli of porcine serum and colostral immunoglobulins and the role of lysozyme with secretory IgA

    Science.gov (United States)

    Hill, I. R.; Porter, P.

    1974-01-01

    Gel filtration and immune inhibition techniques were used to study bactericidal activities of IgG, IgM and IgA against smooth strains of Escherichia coli 0141 and 08 in sow serum and colostrum and post-colostral piglet serum. Bactericidal activity in sow sera was primarily associated with IgM and a low molecular weight IgG component, 7S IgG activity was less frequently observed. In colostral whey fractions and post-colostral piglet sera, in the absence of lysozyme, bactericidal antibody activity was associated with IgM and 7S IgG. In post-colostral serum bactericidal antibody was also attributable to a low molecular weight form of IgG. IgA in serum from the sow and neonate showed no bactericidal activity, even in the presence of lysozyme, whereas in colostrum secretory 11S IgA had bactericidal activity, but only in the presence of complement and lysozyme. PMID:4212358

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

    OpenAIRE

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

    1997-01-01

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

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

    Science.gov (United States)

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

    1990-09-01

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

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

    Science.gov (United States)

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

    2002-06-01

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

  7. Bactericidal Activity of Ceragenin CSA-13 in Cell Culture and in an Animal Model of Peritoneal Infection.

    Science.gov (United States)

    Bucki, Robert; Niemirowicz, Katarzyna; Wnorowska, Urszula; Byfield, Fitzroy J; Piktel, Ewelina; Wątek, Marzena; Janmey, Paul A; Savage, Paul B

    2015-10-01

    Ceragenins constitute a novel family of cationic antibiotics characterized by a broad spectrum of antimicrobial activities, which have mostly been assessed in vitro. Using a polarized human lung epithelial cell culture system, we evaluated the antibacterial activities of the ceragenin CSA-13 against two strains of Pseudomonas aeruginosa (PAO1 and Xen5). Additionally, the biodistribution and bactericidal activity of a CSA-13-IRDye 800CW derivate were assessed using an animal model of peritoneal infection after PAO1 challenge. In cell culture, CSA-13 bactericidal activities against PAO1 and Xen5 were higher than the activities of the human cathelicidin peptide LL-37. Increased CSA-13 activity was observed in polarized human lung epithelial cell cultures subjected to butyric acid treatment, which is known to increase endogenous LL-37 production. Eight hours after intravenous or intraperitoneal injection, the greatest CSA-13-IRDye 800CW accumulation was observed in mouse liver and kidneys. CSA-13-IRDye 800CW administration resulted in decreased bacterial outgrowth from abdominal fluid collected from animals subjected to intraperitoneal PAO1 infection. These observations indicate that CSA-13 may synergistically interact with antibacterial factors that are naturally present at mucosal surfaces and it maintains its antibacterial activity in the infected abdominal cavity. Cationic lipids such as CSA-13 represent excellent candidates for the development of new antibacterial compounds. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Terminal carbohydrates abundance, immune related enzymes, bactericidal activity and physico-chemical parameters of the Senegalese sole (Solea senegalensis, Kaup) skin mucus.

    Science.gov (United States)

    Guardiola, Francisco A; Cuartero, María; Del Mar Collado-González, María; Díaz Baños, F Guillermo; Cuesta, Alberto; Moriñigo, Miguel Ángel; Esteban, M Ángeles

    2017-01-01

    Recently, interest in mucosal surfaces, more specifically fish skin and its secreted mucus, has greatly increased among immunologists. The abundance of terminal carbohydrates, several enzymes (proteases, lysozyme, peroxidase, alkaline phosphatase, esterases and ceruloplasmin), bactericidal activity against fish pathogenic and non-pathogenic bacteria and several physico-chemical parameters (protein concentration, pH, conductivity, redox potential, osmolarity, density and viscosity) in the skin mucus of Senegalese sole (Solea senegalensis, Kaup) have been evaluated. Present results evidence the abundance of N-acetylneuraminic acid, mannose, glucose and N-acetyl-galactosamine in skin mucus. The levels of lysozyme, proteases, esterases and alkaline phosphatase were very similar (from 20 to 30 Units mg(-1) protein). However, 93 Units mg(-1) protein were detected of ceruloplasmin and only 4'88 Units mg(-1) protein of peroxidase. Skin mucus of S. senegalensis showed high bactericidal activity against the tested pathogen bacteria but weak activity against non-pathogenic bacteria. Finally, a clear relationship between mucus density and temperature was detected, while viscosity showed a direct shear- and temperature-dependent behaviour. These results could be useful for better understanding the role of the skin mucus as a key component of the innate immune system, as well as, for elucidating possible relationships between biological and physico-chemical parameters and disease susceptibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Preliminary investigation of catalytic, antioxidant, anticancer and bactericidal activity of green synthesized silver and gold nanoparticles using Actinidia deliciosa.

    Science.gov (United States)

    Naraginti, Saraschandra; Li, Yi

    2017-05-01

    Herein we report a rapid low cost one step green synthetic method using Actinidia deliciosa fruit extract for preparation of stable and multifunctional silver and gold nanoparticles. The synthesized nanoparticles were successfully used as green catalysts for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB). The enhanced biological activity of the prepared nanoparticles was investigated based on its highly stable antioxidant, anticancer and bactericidal effects. TEM micrographs showed that the silver nanoparticles (AgNPs) formed were predominantly spherical in shape having diameters ranging from 25 to 40nm, while gold nanoparticles (AuNPs) shown particle size ranges from 7 to 20nm. EDAX (energy-dispersive X-ray spectroscopy) and XPS (X-ray photoelectron spectroscopy) results confirmed the presence of elemental silver and gold. X-ray diffraction (XRD) pattern revealed the formation of face-centered cubic structure for AgNPs and AuNPs. The Fourier-transform infrared (FTIR) spectrum indicated the presence of possible functional groups in the biomolecule responsible for capping the nanoparticles. The AgNPs treated HCT116 cells showed 78% viability at highest concentration (350μg/mL), while AuNPs showed 71% viability at highest concentration (350μg/mL) using MTT assay, which provides promising approach for alternative nano-drug development. The antimicrobial activity of the nanoparticles was investigated using Pseudomonas aeruginosa (P.aeruginosa) in which damaging the cell membrane was observed by TEM images. Our results revealed that the green synthesis method is easy, rapid, inexpensive, eco-friendly and efficient in developing multifunctional nanoparticles in near future in the field of biomedicine, water treatment and nanobiotechnology. Copyright © 2017. Published by Elsevier B.V.

  10. 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.

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

    Science.gov (United States)

    Yemmireddy, Veerachandra K; Hung, Yen-Con

    2015-07-02

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

  12. 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.

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2011-09-01

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

  15. 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.

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

    Science.gov (United States)

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

    2017-01-01

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

  17. 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.

  18. 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.

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

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  20. Platelets Mediate Host Defense against Staphylococcus aureus through Direct Bactericidal Activity and by Enhancing Macrophage Activities.

    Science.gov (United States)

    Ali, Ramadan A; Wuescher, Leah M; Dona, Keith R; Worth, Randall G

    2017-01-01

    Platelets are the chief effector cells in hemostasis. However, recent evidence suggests they have multiple roles in host defense against infection. Reports by us and others showed that platelets functionally contribute to protection against Staphylococcus aureus infection. In the current study, the capacity of mouse platelets to participate in host defense against S. aureus infection was determined by assessing two possibilities. First, we determined the ability of platelets to kill S. aureus directly; and, second, we tested the possibility that platelets enhance macrophage phagocytosis and intracellular killing of S. aureus In this study we report evidence in support of both mechanisms. Platelets effectively killed two different strains of S. aureus. A clinical isolate of methicillin-resistant S. aureus was killed by platelets (>40% killing in 2 h) in a thrombin-dependent manner whereas a methicillin-sensitive strain was killed to equal extent but did not require thrombin. Interestingly, thrombin-stimulated platelets also significantly enhanced peritoneal macrophage phagocytosis of both methicillin-resistant S. aureus and methicillin-sensitive S. aureus by >70%, and restricted intracellular growth by >40%. Enhancement of macrophage anti-S. aureus activities is independent of contact with platelets but is mediated through releasable products, namely IL-1β. These data confirm our hypothesis that platelets participate in host defense against S. aureus both through direct killing of S. aureus and enhancing the antimicrobial function of macrophages in protection against S. aureus infection. Copyright © 2016 by The American Association of Immunologists, Inc.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-01

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

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

    NARCIS (Netherlands)

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

    2005-01-01

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

  3. Aging Enhances Production of Reactive Oxygen Species and Bactericidal Activity in Peritoneal Macrophages by Up-Regulating Classical Activation Pathways

    Science.gov (United States)

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

    2011-01-01

    Maintenance of macrophages in their basal state and their rapid activation in response to pathogen detection is 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 mo) and aged (14–15 mo) Balb/c mice. In agreement with prior suggestions, we observe age-dependent increases in macrophage recruitment 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 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 proteins linked to immune cell pathways under both basal conditions and following LPS activation. Immune pathways up-regulated in macrophages isolated from aged mice include proteins critical to formation of the immunoproteasome. Detection of these latter proteins are 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 many proteins involved in immune cell function in aged Balb/c mice. Collectively these results indicate that macrophages isolated from

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-07

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

  5. In vitro bactericidal activity of Jinghua Weikang Capsule and its individual herb Chenopodium ambrosioides L. against antibiotic-resistant Helicobacter pylori.

    Science.gov (United States)

    Liu, Wei; Liu, Yu; Zhang, Xue-Zhi; Li, Ning; Cheng, Hong

    2013-01-01

    To investigate the bactericidal effects of Jinghua Weikang Capsule and its major component Chenopodium ambrosioides L. on antibiotic-resistant Helicobacter pylori. Four clinical antibiotic-resistant H. pylori strains were isolated and incubated in liquid medium containing Jinghua Weikang Capsule or Chenopodium ambrosioides L. By means of time-kill curve method, the average colony counts and bactericidal rate were calculated at time points of 0, 4, 8 and 24 h after the incubation and the time-kill curves were charted. Both Jinghua Weikang Capsule and Chenopodium ambrosioides L. at a concentration of 0.64 g/L showed obvious bactericidal effect against antibiotic-resistant H. pylori after 4 h of incubation. Jinghua Weikang Capsule and Chenopodium ambrosioides L. are considered to be active against antibiotic-resistant H. pylori in vitro.

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

    Science.gov (United States)

    Pinasi, C; Albini, E; Marca, G

    1987-01-01

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

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

    Science.gov (United States)

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

    2016-01-28

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

  8. Epithelial Cell Damage Activates Bactericidal/Permeability Increasing-Protein (BPI Expression in Intestinal Epithelium

    Directory of Open Access Journals (Sweden)

    Arjun Balakrishnan

    2017-08-01

    Full Text Available As the first line of defense against invading pathogen, intestinal epithelium produces various antimicrobial proteins (AMP that help in clearance of pathogen. Bactericidal/permeability-increasing protein (BPI is a 55 kDa AMP that is expressed in intestinal epithelium. Dysregulation of BPI in intestinal epithelium is associated with various inflammatory diseases like Crohn’s Disease, Ulcerative colitis, and Infectious enteritis’s. In this paper, we report a direct correlation between intestinal damage and BPI expression. In Caco-2 cells, we see a significant increase in BPI levels upon membrane damage mediated by S. aureus infection and pore-forming toxins (Streptolysin and Listeriolysin. Cells detect changes in potassium level as a Danger-associated molecular pattern associated with cell damage and induce BPI expression in a p38 dependent manner. These results are further supported by in vivo findings that the BPI expression in murine intestinal epithelium is induced upon infection with bacteria which cause intestinal damage (Salmonella Typhimurium and Shigella flexneri whereas mutants that do not cause intestinal damage (STM ΔfliC and STM ΔinvC did not induce BPI expression. Our results suggest that epithelial damage associated with infection act as a signal to induce BPI expression.

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

    Institute of Scientific and Technical Information of China (English)

    WANG Xun; GONG Wenqi

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-01

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

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

    Science.gov (United States)

    Kampf, G; Hollingsworth, A

    2003-11-01

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

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

    Science.gov (United States)

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

  13. 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

  14. 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.

  15. Bactericidal effects of a high-power, red light-emitting diode on two periodontopathic bacteria in antimicrobial photodynamic therapy in vitro.

    Science.gov (United States)

    Umeda, Makoto; Tsuno, Akiko; Okagami, Yoshihide; Tsuchiya, Fumito; Izumi, Yuichi; Ishikawa, Isao

    2011-11-01

      Light-emitting diodes have been investigated as new light activators for photodynamic therapy. We investigated the bactericidal effects of high-power, red light-emitting diodes on two periodontopathic bacteria in vitro.   A light-emitting diode (intensity: 1100 mW/cm(2) , peak wavelength: 650 nm) was used to irradiate a bacterial solution for either 10 or 20 s. Bacterial solutions (Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans) at a concentration of 2.5 × 10(6) c.f.u./mL were mixed with an equal volume of either methylene blue or toluidine blue O (0-20 μg/mL) and added to titer plate wells. The plate wells were irradiated with red light-emitting diode light from a distance of 22 or 40 mm. The contents were diluted, and 50 μL was smeared onto blood agar plates. After 1 week of culturing, bacterial c.f.u. were counted.   The light-emitting diode energy density was estimated to be approximately 4 and 8 J/cm(2) after 10 and 20 s of irradiation, respectively. Red light-emitting diode irradiation for 10 s from a distance of 22 mm, combined with methylene blue at concentrations >10 μg/mL, completely killed Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.   High-power, red light-emitting diode irradiation with a low concentration of dye showed effective bactericidal effects against two periodontopathic bacteria. © 2011 Blackwell Publishing Asia Pty Ltd.

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

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

    1997-04-01

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

  18. 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.

  19. Propolis modulates miRNAs involved in TLR-4 pathway, NF-κB activation, cytokine production and in the bactericidal activity of human dendritic cells.

    Science.gov (United States)

    Conti, Bruno J; Santiago, Karina B; Cardoso, Eliza O; Freire, Paula P; Carvalho, Robson F; Golim, Marjorie A; Sforcin, José M

    2016-12-01

    Dendritic cells (DCs) are antigen-presenting cells, essential for recognition and presentation of pathogens to T cells. Propolis, a resinous material produced by bees from various plants, exhibits numerous biological properties, highlighting its immunomodulatory action. Here, we assayed the effects of propolis on the maturation and function of human DCs. DCs were generated from human monocytes and incubated with propolis and LPS. NF-κB and cytokines production were determined by ELISA. microRNA's expression was analysed by RT-qPCR and cell markers detection by flow cytometry. Colony-forming units were obtained to assess the bactericidal activity of propolis-treated DCs. Propolis activated DCs in the presence of LPS, inducing NF-kB, TNF-α, IL-6 and IL-10 production. The inhibition of hsa-miR-148a and hsa-miR-148b abolished the inhibitory effects on HLA-DR and pro-inflammatory cytokines. The increased expression of hsa-miR-155 may be correlated to the increase in TLR-4 and CD86 expression, maintaining LPS-induced expression of HLA-DR and CD40. Such parameters may be involved in the increased bactericidal activity of DCs against Streptococcus mutans. Propolis modulated the maturation and function of DCs and may be useful in the initial steps of the immune response, providing a novel approach to the development of DC-based strategies and for the discovery of new immunomodulators. © 2016 Royal Pharmaceutical Society.

  20. 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.

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

    Science.gov (United States)

    Noguchi, Chieko; Koseki, Hironobu

    2016-08-01

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

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

    Science.gov (United States)

    Okamura, N; Spitznagel, J K

    1982-06-01

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

  3. 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.

  4. Silver nanoparticles strongly enhance and restore bactericidal activity of inactive antibiotics against multiresistant Enterobacteriaceae.

    Science.gov (United States)

    Panáček, Aleš; Smékalová, Monika; Večeřová, Renata; Bogdanová, Kateřina; Röderová, Magdaléna; Kolář, Milan; Kilianová, Martina; Hradilová, Šárka; Froning, Jens P; Havrdová, Markéta; Prucek, Robert; Zbořil, Radek; Kvítek, Libor

    2016-06-01

    Bacterial resistance to conventional antibiotics is currently one of the most important healthcare issues, and has serious negative impacts on medical practice. This study presents a potential solution to this problem, using the strong synergistic effects of antibiotics combined with silver nanoparticles (NPs). Silver NPs inhibit bacterial growth via a multilevel mode of antibacterial action at concentrations ranging from a few ppm to tens of ppm. Silver NPs strongly enhanced antibacterial activity against multiresistant, β-lactamase and carbapenemase-producing Enterobacteriaceae when combined with the following antibiotics: cefotaxime, ceftazidime, meropenem, ciprofloxacin and gentamicin. All the antibiotics, when combined with silver NPs, showed enhanced antibacterial activity at concentrations far below the minimum inhibitory concentrations (tenths to hundredths of one ppm) of individual antibiotics and silver NPs. The enhanced activity of antibiotics combined with silver NPs, especially meropenem, was weaker against non-resistant bacteria than against resistant bacteria. The double disk synergy test showed that bacteria produced no β-lactamase when treated with antibiotics combined with silver NPs. Low silver concentrations were required for effective enhancement of antibacterial activity against multiresistant bacteria. These low silver concentrations showed no cytotoxic effect towards mammalian cells, an important feature for potential medical applications.

  5. Exploring a new phenomenon in the bactericidal response of TiO{sub 2} thin films by Fe doping: Exerting the antimicrobial activity even after stoppage of illumination

    Energy Technology Data Exchange (ETDEWEB)

    Naghibi, Sanaz, E-mail: naghibi@iaush.ac.ir [Department of Metallurgy and Materials Engineering, Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Vahed, Shohreh, E-mail: sh_vahed@iaush.ac.ir [Department of Food Science, Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Torabi, Omid, E-mail: omid_trb@yahoo.com [Department of Materials Engineering, Najafabad Branch, Advanced Materials Research Center, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Jamshidi, Amin, E-mail: amin_jam_g@yahoo.com [Department of Materials Engineering, Najafabad Branch, Advanced Materials Research Center, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Golabgir, Mohammad Hossein, E-mail: m.hosseingolabgir@yahoo.com [Department of Materials Engineering, Najafabad Branch, Advanced Materials Research Center, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

    2015-02-01

    Graphical abstract: - Highlights: • Highly uniform Fe–TiO{sub 2} thin films were deposited on glass using sol–gel hot-dipping technique. • The photocatalytic properties were studied upon UV and visible irradiation. • By Fe doping into TiO{sub 2} structure, its microbial performance was prolonged even after stopping the illumination. • Due to Fe doping, the significant improvement in bactericidal coating was evident. - Abstract: Antibacterial properties of Fe-doped TiO{sub 2} thin films prepared on glass by the sol–gel hot-dipping technique were studied. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, scanning probe microscopy and X-ray photoelectron spectroscopy. The photocatalytic activities were evaluated by measuring the decomposition rate of methylene blue under ultra violet and visible light. The antibacterial properties of the coatings were investigated against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisia and Aspergillus niger. The principle of incubation methods was also discussed. The results indicated that Fe doping of thin films eventuated in high antibacterial properties under visible light and this performance remained even after stoppage of illumination. This article tries to provide some explanation for this fact.

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

    Science.gov (United States)

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

    2014-09-01

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

  7. Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition

    OpenAIRE

    Ponja, S. D.; Sehmi, S. K.; Allan, E.; MacRobert, A. J.; Parkin, I. P.; Carmalt, C. J.

    2015-01-01

    Silver thin films were deposited on SiO2-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO2-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activit...

  8. Bactericidal activity of black pepper, bay leaf, aniseed and coriander against oral isolates.

    Science.gov (United States)

    Chaudhry, Nazia Masood Ahmed; Tariq, Perween

    2006-07-01

    Present investigation focused on antibacterial potential of aqueous decoction of black pepper (Piper nigrum L.), bay leaf (Laurus nobilis L.), aniseed (Pimpinella anisum L.), and coriander (Coriandum sativum L.) against 176 bacterial isolates belonging to 12 different genera of bacterial population isolated from oral cavity of 200 individuals. The disc diffusion technique was employed. Overall aqueous decoction of black pepper was the most bacterial-toxic exhibited 75% antibacterial activity as compared to aqueous decoction of bay leaf (53.4%) and aqueous decoction of aniseed (18.1%), at the concentration of 10 ml/disc. The aqueous decoction of coriander did not show any antibacterial effect against tested bacterial isolates.

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

    Science.gov (United States)

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

    2012-09-01

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

  10. Bactericidal and ammonia removal activity of silver ion-exchanged zeolite.

    Science.gov (United States)

    Krishnani, K K; Zhang, Yu; Xiong, Laj; Yan, Yushan; Boopathy, Raj; Mulchandani, Ashok

    2012-08-01

    The antimicrobial activity of silver-zeolite against Escherichia coli, Vibrio harveyi, Vibrio cholerae and Vibrio parahaemolyticus was examined in liquid medium and agar well diffusion assays. The minimum inhibitory concentration for silver ion-exchanged zeolite against E. coli and V. harveyi was 40 μg/ml, and 50-60 μg/ml for V. cholerae and V. parahaemolyticus. The diameter of the inhibition zones for E. coli, V. harveyi, V. cholerae and V. parahaemolyticus, respectively, increased from 0.5 to 2.3 cm, 0.6 to 2.4 cm, 0.3 to 1.65 cm and 0.3 to 1.7 cm with increasing concentrations of silver ion-exchanged zeolite from 10 to 400 μg. Silver-zeolite removed 20-37% ammonia from aqueous solutions. This study suggests that silver ion-exchanged zeolite could impact disease and environmental management in shrimp aquaculture.

  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. Nanocrystal Cu2O-loaded TiO2 nanotube array films as high-performance visible-light bactericidal photocatalyst.

    Science.gov (United States)

    Zhang, Shengsen; Liu, Chang; Liu, Xiaolu; Zhang, Haimin; Liu, Porun; Zhang, Shanqing; Peng, Feng; Zhao, Huijun

    2012-12-01

    In this work, we report the use of a non-toxic nanocrystal Cu(2)O-loaded TiO(2) nanotube array (Cu(2)O/TNTs) film as high-performance visible-light bactericidal photocatalyst. The samples were characterized by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible diffusion reflection spectroscopy. This Cu(2)O/TNTs film photocatalyst is capable of complete inactivation of Escherichia coli in 5 × 10(7) colony-forming units/mL within a record short disinfection time of 20 min under visible-light irradiation. The average bactericidal percentage of the Cu(2)O/TNTs for E. coli under visible-light irradiation are 20 times and 6.6 times higher than those of TNTs under the same conditions and Cu(2)O/TNTs without light, respectively. This superior bactericidal performance is mainly attributed to the high ability to produce OH radicals by both photogenerated electron and hole of the prepared photocatalyst under visible light. The Cu(2)O/TNTs film photocatalyst makes it applicable to broad fields including drinking water disinfection.

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

    Directory of Open Access Journals (Sweden)

    Kai Syin Lee

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

  14. Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current

    Directory of Open Access Journals (Sweden)

    Żaneta Król

    2017-03-01

    Full Text Available The aim of the study was to investigate the effect of using direct electric current (DC of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP, electrical conductivity (EC, and available chlorine concentration (ACC were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH and ferric reducing antioxidant power (FRAP. The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples.

  15. Bactericidal Activity of TiO2 on Cells of Pseudomonas aeruginosa ATCC 27853

    Directory of Open Access Journals (Sweden)

    J. L. Aguilar Salinas

    2013-01-01

    Full Text Available The photocatalytic activity of semiconductors is increasingly being used to disinfect water, air, soils, and surfaces. Titanium dioxide (TiO2 is widely used as a photocatalyst in thin films, powder, and in mixtures with other semiconductors or metals. This work presents the antibacterial effects of TiO2 and light exposure (at 365 nm on Pseudomonas aeruginosa ATCC 27853. TiO2 powder was prepared from a mixture of titanium isopropoxide, ethanol, and nitric acid using a green and short time sol-gel technique. The obtained gel annealed at 450°C was characterized by X-ray diffraction, Raman spectroscopy, ultraviolet-visible spectroscopy, diffuse reflectance, scanning electron microscopy, and transmission electron microscopy. The nanocomposite effectively catalyzed the inactivation of Pseudomonas aeruginosa. Following 90 minutes exposure to TiO2 and UV light, logarithm of cell density was reduced from 6 to 3. These results were confirmed by a factorial design incorporating two experimental replicates and two independent factors.

  16. Cytotoxicity, Bactericidal, and Antioxidant Activity of Sodium Alginate Hydrosols Treated with Direct Electric Current.

    Science.gov (United States)

    Król, Żaneta; Marycz, Krzysztof; Kulig, Dominika; Marędziak, Monika; Jarmoluk, Andrzej

    2017-03-22

    The aim of the study was to investigate the effect of using direct electric current (DC) of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP), electrical conductivity (EC), and available chlorine concentration (ACC) were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW 264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and ferric reducing antioxidant power (FRAP). The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples.

  17. Acorus calamus rhizome extract mediated biosynthesis of silver nanoparticles and their bactericidal activity against human pathogens

    Directory of Open Access Journals (Sweden)

    Chinnappan Sudhakar

    2015-12-01

    Full Text Available Silver nanoparticle (AgNP synthesis and characterization is an area of vast interest due to their broader application in the fields of science and technology and medicine. Plants are an attractive source for AgNP synthesis because of its ability to produce a wide range of secondary metabolites with strong reducing potentials. Thus, the present study describes the synthesis of AgNPs using aqueous rhizome extract of Acorus calamus (sweet flag. The AgNP formation was evaluated at different temperatures, incubation time and concentrations of AgNO3 using Response surface methodology based Box–Behnken design (BBD. The synthesized AgNPs were characterized by UV–Visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR, X-ray diffraction (XRD, and Scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS. The surface plasmon resonance found at 420 nm confirmed the formation of AgNPs. SEM images reveal that the particles are spherical in nature. The EDS analysis of the AgNPs, using an energy range of 2–4 keV, confirmed the presence of elemental silver without any contamination. The antibacterial activity of synthesized AgNPs was evaluated against the clinical isolates Staphylococcus aureus and Escherichia coli and it was found that bacterial growth was significantly inhibited in a dose dependent manner. The results suggest that the AgNPs from rhizome extract could be used as a potential antibacterial agent for commercial application.

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

    Directory of Open Access Journals (Sweden)

    Kasuga E

    2011-09-01

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

  19. Bactericidal effects of high-power Nd:YAG laser radiation on Staphylococcus aureus

    Science.gov (United States)

    Yeo, C. B. Allen; Watson, Ian A.; Stewart-Tull, Duncan E. S.; Wardlaw, A. C.; Armstrong, Graham N.

    1998-05-01

    The effect of laser radiation on Staphylococcus aureus 6571 (Oxford strain) was studied with high-power Nd:YAG laser radiation between 50 and 300 W. A range of laser pulse repetition frequencies (PRF) from 5 to 30 Hz, with a combination of pulse energies from 2 to 30 J were applied; this covered a range of energy densities from 800 to 0963-9659/7/3/020/img8. The area of inactivation of S. aureus, lawned on nutrient agar plates, was quantified as a function of energy density and exposure time. The shortest exposure time which produced an area of inactivation equal to 50% of the beam area was achieved at a PRF of 30 Hz, pulse energy of 10 J, and with an exposure time of 10.75 s; this was equivalent to an applied energy density of 0963-9659/7/3/020/img9. No bacterial inactivation was observed at relatively low-power settings for PRF, pulse energies and exposure time of: 20 Hz, 3 J and 34 s; 25 Hz, 2 J and 45 s and 30 Hz, 2 J and 35 s, respectively. These results shows that pulse energy, PRF and exposure time are important criteria when considering inactivation of micro-organisms by laser radiation.

  20. 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.

  1. Superior bactericidal activity of N-bromine compounds compared to their N-chlorine analogues can be reversed under protein load.

    Science.gov (United States)

    Gottardi, W; Klotz, S; Nagl, M

    2014-06-01

    To investigate and compare the bactericidal activity (BA) of active bromine and chlorine compounds in the absence and presence of protein load. Quantitative killing tests against Escherichia coli and Staphylococcus aureus were performed both in the absence and in the presence of peptone with pairs of isosteric active chlorine and bromine compounds: hypochlorous and hypobromous acid (HOCl and HOBr), dichloro- and dibromoisocyanuric acid, chlorantine and bromantine (1,3-dibromo- and 1,3 dichloro-5,5-dimethylhydantoine), chloramine T and bromamine T (N-chloro- and N-bromo-4-methylbenzenesulphonamide sodium), and N-chloro- and N-bromotaurine sodium. To classify the bactericidal activities on a quantitative basis, an empirical coefficient named specific bactericidal activity (SBA), founded on the parameters of killing curves, was defined: SBA= mean log reductions/(mean exposure times x concentration) [mmol 1(-1) min (-1)]. In the absence of peptone, tests with washed micro-organisms revealed a throughout higher BA of bromine compounds with only slight differences between single substances. This was in contrast to chlorine compounds, whose killing times differed by a factor of more than four decimal powers. As a consequence, also the isosteric pairs showed according differences. In the presence of peptone, however, bromine compounds showed an increased loss of BA, which partly caused a reversal of efficacy within isosteric pairs. In medical practice, weakly oxidizing active chlorine compounds like chloramines have the highest potential as topical anti-infectives in the presence of proteinaceous material (mucous membranes, open wounds). Active bromine compounds, on the other hand, have their chance at insensitive body regions with low organic matter, for example skin surfaces. The expected protein load is one of the most important parameters for selection of a suited active halogen compound. © 2014 The Society for Applied Microbiology.

  2. 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

  3. EVALUATION OF BACTERICIDAL EFFECTIVENESS OF BENZALKONIUM CHLORIDE

    OpenAIRE

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

    1996-01-01

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

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

    Science.gov (United States)

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

    2010-10-01

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

  5. THE BACTERICIDAL ACTION OF SYNTHETIC DETERGENTS.

    Science.gov (United States)

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

    1941-11-30

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

  6. In situ production of human β defensin-3 in lager yeasts provides bactericidal activity against beer-spoiling bacteria under fermentation conditions.

    Science.gov (United States)

    James, T C; Gallagher, L; Titze, J; Bourke, P; Kavanagh, J; Arendt, E; Bond, U

    2014-02-01

    To examine the use of a natural antimicrobial peptide, human β-defensin-3 (HBD3), as a means of preventing spoilage from bacterial contamination in brewery fermentations and in bottled beer. A chemically synthesised HBD3 peptide was tested for bactericidal activity against common Gram-positive and Gram-negative beer-spoiling bacteria, including species of Lactobacillus, Pediococcus and Pectinatus. The peptide was effective at the μmol l(-1) range in vitro, reducing bacterial counts by 95%. A gene construct encoding a secretable form of HBD3 was integrated into the genome of the lager yeast Saccharomyces pastorianus strain CMBS-33. The integrated gene was expressed under fermentation conditions and was secreted from the cell into the medium, but a significant amount remains associated with yeast cell surface. We demonstrate that under pilot-scale fermentation conditions, secreted HBD3 possesses bactericidal activity against beer-spoiling bacteria. Furthermore, when added to bottled beer, a synthetic form of HBD3 reduces the growth of beer-spoiling bacteria. Defensins provide prophylactic protection against beer-spoiling bacteria under brewing conditions and also in bottled beer. The results have direct application to the brewing industry where beer spoilage due to bacterial contamination continues to be a major problem in breweries around the world. © 2013 The Society for Applied Microbiology.

  7. 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.

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

    Science.gov (United States)

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

    2016-05-01

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

  9. 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.

  10. Bactericidal application and cytotoxic activity of biosynthesized silver nanoparticles with an extract of the red seaweed Pterocladiella capillacea on the HepG2 cell line.

    Science.gov (United States)

    El Kassas, Hala Yassin; Attia, Azza Ahmed

    2014-01-01

    Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine. Biologically synthesized silver nanoparticles have a wide range of applications. Silver nanoparticles (AgNPs) were biosynthesized with an aqueous extract of Pterocladiella (Pterocladia) capillacea, used as a reducing and stabilizing agent, and characterized using UV-VIS spectroscopy, Fourier Transform Infra red (FT-IR) spectroscopy, transmission electron microscopy (TEM) and energy dispersive analysis (EDX). The biosynthesized AgNPs were tested for cytotoxic activity in a human hepatocellular carcinoma (HepG2) cell line cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 1% antibiotic and antimycotic solution and 2 mM glutamine. Bacterial susceptibility to AgNPs was assessed with Staphylococcus aureus, Bacillus subtilis [Gram+ve] and Pseudomonas aeruginosa and Escherichia coli [Gram-ve]. The agar well diffusion technique was adopted to evaluate the bactericidal activity of the biosynthesized AgNPs using Ampicillin and Gentamicin as gram+ve and gram-ve antibacterial standard drugs, respectively. The biosynthesized AgNPs were 11.4±3.52 nm in diameter. FT-IR analysis showed that carbonyl groups from the amino acid residues and proteins could assist in formation and stabilization of AgNPs. The AgNPs showed potent cytotoxic activity against the human hepatocellular carcinoma (HepG2) cell line at higher concentrations. The results also showed that the biosynthesized AgNPs inhibited the entire panel of tested bacteria with a marked specificity towards Bacillus subtillus. Cytotoxic activity of the biosynthesized AgNPs may be due to the presence of alkaloids present in the algal extract. Our AgNPs appear more bactericidal against gram-positive bacteria (B. subtillus).

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

    Science.gov (United States)

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

    2001-12-01

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

  12. Colloidal titania-silica-iron oxide nanocomposites and the effect from silica thickness on the photocatalytic and bactericidal activities

    Science.gov (United States)

    Chanhom, Padtaraporn; Charoenlap, Nisanart; Tomapatanaget, Boosayarat; Insin, Numpon

    2017-04-01

    New types of colloidal multifunctional nanocomposites that combine superparamagnetic character and high photocatalytic activity were synthesized and investigated. The superparamagnetic nanocomposites composed of anatase titania, silica, and iron oxide nanoparticles (TSI) were synthesized using thermal decomposition method followed by microemulsion method, without calcination at high temperature. Different techniques including X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize and confirm the structure of the nanocomposites. These nanocomposites showed high photocatalytic activity when used in the photodegradation of methylene blue under irradiation with a black light lamp. Moreover, the nanocomposites exhibited high antibacterial properties. From our study, the nanocomposites can be useful in various applications such as removal of pollutants with readily separation from the environment using an external magnetic field. These composites could effectively photo-degrade the dye at least three cycles without regeneration. The effects of silica shell thickness on the photocatalytic activity was investigated, and the thickness of 6 nm of the silica interlayer is enough for the inhibition of electron translocation between titania and iron oxide nanoparticles and maintaining the efficiency of photocatalytic activity of titania nanoparticles.

  13. EVALUATION OF BACTERICIDAL EFFECTIVENESS OF BENZALKONIUM CHLORIDE

    Directory of Open Access Journals (Sweden)

    K. Imandel

    1996-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-01

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

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

    Institute of Scientific and Technical Information of China (English)

    万正龙; 蔡杰; 刘森; 熊汉国

    2011-01-01

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

  16. 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.

  17. 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.

  18. Naphthalimides Selectively Inhibit the Activity of Bacterial, Replicative DNA Ligases and Display Bactericidal Effects against Tubercle Bacilli

    Directory of Open Access Journals (Sweden)

    Malgorzata Korycka-Machala

    2017-01-01

    Full Text Available The DNA ligases, enzymes that seal breaks in the backbones of DNA, are essential for all organisms, however bacterial ligases essential for DNA replication use β-nicotinamide adenine dinucleotide as their co-factor, whereas those that are essential in eukaryotes and viruses use adenosine-5′-triphosphate. This fact leads to the conclusion that NAD+-dependent DNA ligases in bacteria could be targeted by their co-factor specific inhibitors. The development of novel alternative medical strategies, including new drugs, are a top priority focus areas for tuberculosis research due to an increase in the number of multi-drug resistant as well as totally drug resistant tubercle bacilli strains. Here, through the use of a virtual high-throughput screen and manual inspection of the top 200 records, 23 compounds were selected for in vitro studies. The selected compounds were evaluated in respect to their Mycobacterium tuberculosis NAD+ DNA ligase inhibitory effect by a newly developed assay based on Genetic Analyzer 3500 Sequencer. The most effective agents (e.g., pinafide, mitonafide inhibited the activity of M. tuberculosis NAD+-dependent DNA ligase A at concentrations of 50 µM. At the same time, the ATP-dependent (phage DNA LigT4 was unaffected by the agents at concentrations up to 2 mM. The selected compounds appeared to also be active against actively growing tubercle bacilli in concentrations as low as 15 µM.

  19. 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.

  20. 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

  1. 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.

  2. Cinnamon zeylanicum bark extract and powder mediated green synthesis of nano-crystalline silver particles and its bactericidal activity.

    Science.gov (United States)

    Sathishkumar, M; Sneha, K; Won, S W; Cho, C-W; Kim, S; Yun, Y-S

    2009-10-15

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The present study reports the synthesis of silver (Ag) nanoparticles from silver precursor using the bark extract and powder of novel Cinnamon zeylanicum. Water-soluble organics present in the plant materials were mainly responsible for the reduction of silver ions to nano-sized Ag particles. TEM and XRD results confirmed the presence of nano-crystalline Ag particles. The pH played a major role in size control of the particles. Bark extract produced more Ag nanoparticles than the powder did, which was attributed to the large availability of the reducing agents in the extract. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The EC(50) value of the synthesized nanoparticles against Escherichia coli BL-21 strain was 11+/-1.72 mg/L. Thus C. zeylanicum bark extract and powder are a good bio-resource/biomaterial for the synthesis of Ag nanoparticles with antimicrobial activity.

  3. 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.

  4. Stem bark extract and fraction of Persea americana (Mill.) exhibits bactericidal activities against strains of bacillus cereus associated with food poisoning.

    Science.gov (United States)

    Akinpelu, David A; Aiyegoro, Olayinka A; Akinpelu, Oluseun F; Okoh, Anthony I

    2014-12-30

    The study investigates the in vitro antibacterial potentials of stem bark extracts of Persea americana on strains of Bacillus cereus implicated in food poisoning. The crude stem bark extracts and butanolic fraction at a concentration of 25 mg/mL and 10 mg/mL, respectively, exhibited antibacterial activities against test isolates. The zones of inhibition exhibited by the crude extract and the fraction ranged between 10 mm and 26 mm, while the minimum inhibitory concentration values ranged between 0.78 and 5.00 mg/mL. The minimum bactericidal concentrations ranged between 3.12 mg/mL-12.5 mg/mL and 1.25-10 mg/mL for the extract and the fraction, respectively. The butanolic fraction killed 91.49% of the test isolates at a concentration of 2× MIC after 60 min of contact time, while a 100% killing was achieved after the test bacterial cells were exposed to the butanolic fraction at a concentration of 3× MIC after 90 min contact time. Intracellular protein and potassium ion leaked out of the test bacterial cells when exposed to certain concentrations of the fraction; this is an indication of bacterial cell wall disruptions by the extract's butanolic fraction and, thus, caused a biocidal effect on the cells, as evident in the killing rate test results.

  5. 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.

  6. Eco-friendly synthesis of silver and gold nanoparticles with enhanced bactericidal activity and study of silver catalyzed reduction of 4-nitrophenol.

    Science.gov (United States)

    Naraginti, Saraschandra; Sivakumar, A

    2014-07-15

    The present study reports a simple and robust method for synthesis of silver and gold nanoparticles using Coleus forskohlii root extract as reducing and stabilizing agent. Stable silver nanoparticles (AgNPs) and gold nanopoarticles (AuNPs) were formed on treatment of an aqueous silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solutions with the root extract. The nanoparticles obtained were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). UV-Vis and TEM analysis indicate that with higher quantities of root extract, the interaction is enhanced leading to size reduction of spherical metal nanoparticles. XRD confirms face-centered cubic phase and the diffraction peaks can be attributed to (111), (200), (222) and (311) planes for these nanoparticles. These synthesized Ag and Au nanoparticles were found to exhibit excellent bactericidal activity against clinically isolated selected pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The synthesized AgNPs were also found to function as an efficient green catalyst in the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride, which was apparent from the periodical color change from bright yellow to colorless, after the addition of AgNPs.

  7. The enhanced photocatalytic and bactericidal activities of carbon microsphere-assisted solvothermally synthesized cocoon-shaped Sn(4+)-doped ZnO nanoparticles.

    Science.gov (United States)

    Karunakaran, Chockalingam; SakthiRaadha, SakthiDasan; Gomathisankar, Paramasivan; Vinayagamoorthy, Pazhamalai

    2013-10-14

    Cocoon-shaped Sn(4+)-doped ZnO nanoparticles have been synthesized by a solvothermal method using carbon microspheres as a template. The optimum doping level for photocatalysis is 3% (g. atom). Powder X-ray diffractograms show that the ZnO has a primitive hexagonal crystal structure and that doping ZnO with Sn(4+) increases the unit cell lengths and the Zn-O bond lengths. Larger crystal growth along the c-axis is also observed. The measured size of the cocoon-shaped Sn(4+)-doped ZnO nanoparticles is larger than the mean crystallite size. Solid state impedance spectroscopy studies reveal that Sn(4+)-doping increases the charge transfer resistance. Doping does not significantly modify the optical band gap, but does suppress green emission. A decrease in the number of crystal defects due to oxygen vacancies is likely to be a reason for the enhanced photocatalytic properties of the cocoon-shaped Sn(4+)-doped ZnO nanoparticles. Doping ZnO with Sn(4+) enhances the bactericidal activity as well.

  8. 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.

  9. 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.

  10. Shape-dependent bactericidal activity of TiO2 for the killing of Gram-negative bacteria Agrobacterium tumefaciens under UV torch irradiation.

    Science.gov (United States)

    Aminedi, Raghavendra; Wadhwa, Gunveen; Das, Niranjan; Pal, Bonamali

    2013-09-01

    This paper demonstrated the relative bactericidal activity of photoirradiated (6W-UV Torch, λ > 340 nm and intensity = 0.64 mW/cm(2)) P25-TiO2 nanoparticles, nanorods, and nanotubes for the killing of Gram-negative bacterium Agrobacterium tumefaciens LBA4404 for the first time. TiO2 nanorod (anatase) with length of 70-100 nm and diameter of 10-12 nm, and TiO2 nanotube with length of 90-110 nm and diameter of 9-11 nm were prepared from P-25 Degussa TiO2 (size, 30-50 nm) by hydrothermal method and compared their biocidal activity both in aqueous slurry and thin films. The mode of bacterial cell decomposition was analyzed through transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR), and K(+) ion leakage. The antimicrobial activity of photoirradiated TiO2 of different shapes was found to be in the order P25-TiO2 > nanorod > nanotube which is reverse to their specific surface area as 54 TiO2 nanoparticles is not due to surface area as their crystal structure and surface morphology are entirely different. TiO2 thin films always exhibited less photoactivity as compared to its aqueous suspension under similar conditions of cell viability test. The changes in the bacterial surface morphology by UV-irradiated P25-TiO2 nanoparticles was examined by TEM, oxidative degradation of cell components such as proteins, carbohydrates, phospholipids, nucleic acids by FT-IR spectral analysis, and K(+) ion leakage (2.5 ppm as compared to 0.4 ppm for control culture) as a measure of loss in cell membrane permeability.

  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. 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

  13. Comparative analyses of the bactericidal activity of snake venoms%蛇毒抗菌的比较性研究

    Institute of Scientific and Technical Information of China (English)

    李妲; 孙明忠; 郭春梅; 彭博雅; 刘淑清

    2013-01-01

    目的 研究蛇毒粗毒的抗菌作用,并比较不同蛇毒对不同细菌的抑制效果.方法 采用抑菌环法测定蛇岛蝮、江浙蝮和短尾蝮蛇毒粗毒对金黄色葡萄球菌、枯草芽孢杆菌、大肠埃希菌、铜绿假单胞菌以及白色念珠菌的抗菌作用,比较不同蛇毒粗毒的抗菌效果;加入过氧化氢酶(catalase),考察蛇毒抗菌作用的变化.结果 (1)3种蛇毒粗毒对5种细菌均呈现不同程度的抑制作用.(2)3种蛇毒粗毒对5种细菌的抑制作用大小依次为:金黄色葡萄球菌>白色念珠菌>大肠埃希菌或铜绿假单胞菌>枯草芽孢杆菌.(3)加入catalase后,蛇毒的抗菌作用明显减弱.结论 (1)3种蛇毒粗毒均具有一定的抗菌作用,并具有明显抑菌选择性.(2)3种蛇毒的抗菌效果不同,蛇岛蝮蛇抗菌作用最强.(3) catalase能显著降低蛇毒的抗菌活性,表明L-氨基酸氧化酶是蛇毒起抗菌作用的主要成分.%Objective To measure and compare the anti-bacterial activity of crude snake venoms against different bacterium strains.Methods The bacteria-inhibiting ring method was applied to measure the anti-bacterial effects of the snake venoms of Gloydius shedaoensis,Agkistrodon halys Pallas and Gloydius brevicaudus on the growths of the bacterium strains of Staphyloccocus aureus,Bacillus subtilis,Escherichia coli,Pseudomonas aeruginosa and Candida albicans.The anti-bacterial activities of different crude snake venoms were then compared.The effect of the addition of catalase was also compared.Results (1) The three crude snake venoms showed varied inhibitory effects on the five types of bacterium tested in current work.(2) Basically,the snake venoms showed the strongest inhibitory effect against Staphyloccocus aureus,followed by Candida albicans,Escherichia coli or Pseudomonas acruginosa and Bacillus subtilis.(3) In the presence of catalase,the anti-bacterial effect of Gloydius shedaoensis vemon was significantly suppressed

  14. Surface functional polymers by post-polymerization modification using diarylcarbenes: introduction, release and regeneration of hydrogen peroxide and bactericidal activity.

    Science.gov (United States)

    Griffiths, Jon-Paul; Maliha, Bushra; Moloney, Mark G; Thompson, Amber L; Hussain, Ishtiaq

    2010-09-07

    Functionalized diarylcarbenes are excellent reactive intermediates suitable for the direct surface modification of organic polymers, and these may be used to introduce urea and thiourea functions onto polystyrene at loading levels of up to 2.3 x 10(13) molecules/cm(2). These functions are capable of the reversible binding and release of peroxide at loading levels of up to 0.6 mmol/g and give polymers that display biocidal activity against a spectrum of gram-positive and gram-negative bacteria.

  15. Bordetella parapertussis Circumvents Neutrophil Extracellular Bactericidal Mechanisms

    Science.gov (United States)

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

    2017-01-01

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

  16. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  18. High loading of graphene oxide/multi-walled carbon nanotubes into PDLLA: A route towards the design of osteoconductive, bactericidal and non-immunogenic 3D porous scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, Hudson [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil); Laboratory of Energy Storage & Supply - ES& S, Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, CEP: 12.244-000, Sao Paulo (Brazil); Rodrigues, Bruno Vinícius Manzolli [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil); Ribeiro Neto, Wilson Alves; Bretas, Rosario Elida Suman [Department of Materials Engineering, Federal University of Sao Carlos, Rodovia Washington Luis, km 235 – SP-310, Sao Carlos, Sao Paulo (Brazil); Da-Silva, Newton Soares [Laboratory of Cell Biology and Tissue, Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, CEP: 12244-000, Sao Paulo (Brazil); Marciano, Fernanda Roberta [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil); Oliveira Lobo, Anderson, E-mail: aolobo@pq.cnpq.br [Laboratory of Biomedical Nanotechnology (NANOBIO), Institute of Research and Development - IP& D, University of Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, Sao Paulo (Brazil)

    2016-07-01

    We have prepared a novel 3D porous biomaterial combining poly (DL-lactic acid) (PDLLA) and graphene and multi-walled carbon nanotubes oxides (MWCNTO-GO) composite. PDLLA as control and a high loading of PDLLA/MWCNTO-GO (50/50 w/w) bioscaffolds were prepared and functionalized. MWCNTs were exfoliated to form MWCNTO-GO by oxygen plasma etching. The later was also applied to enhance the scaffolds wettability, attaching oxygen-containing groups on their surfaces. This approach produced a porous architecture observed by scanning electron microscopy and semi-quantified by electrochemical analysis. The later also indicated a notable increase on the conductivity of PDLLA/MWCNTO-GO scaffold compared to MWCNTO-GO free PDLLA (about 5 orders of magnitudes at low frequencies). Thermogravimetric analysis showed that the MWCNTO-GO acted protecting the PDLLA matrix, enhancing its thermal stability. The PDLLA/MWCNTO-GO scaffolds had significant cellular adhesion, did not present cytotoxicity effect, besides reduced bactericidal proliferation and produced mineralized tissues in SBF media. The metallic MWCNTO-GO powder held together by PDLLA polymer opens a whole new branch of applications, including bioelectroanalyses, drug delivery systems and tissue engineering. - Highlights: • We produced a novel 3D porous material from PDLLA, graphene oxide and MWCNT oxide. • MWCNTO-GO loading (50/50 w/w) increased notably the conductivity of PDLLA scaffold. • MWCNTO-GO acted protecting the PDLLA matrix, enhancing its thermal stability. • PDLLA/MWCNTO-GO scaffolds did not present cytotoxicity effect. • PDLLA/MWCNTO-GO scaffolds presented bioactivity properties.

  19. Bactericidal Activity of Copper Oxide Nanocomposite/Bioglass for in Vitro Clindamycin Release in Implant Infections Due to Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Alijanian

    2016-08-01

    Full Text Available Background In recent years, bioactive bioceramics such as bioglass and hydroxyapatite (HA have been introduced as a remarkable development in the field of medicine due to their bio-adaptability, non-toxicity, and persistence, in vivo. They have many potential applications in the repair of bone defects and hence they have attracted significant interest from scholars. Objectives The aim of this study was to synthesize inorganic matrix CuO-based bioglasses and evaluate their antibacterial activity against aerobic bacterial infections in bone implants. Methods Nano-composite samples of silica-based bioactive glass, 60S BG with nano-powder CuO, were synthesized using the sol-gel method and then assessed with regard to their antibacterial properties against Staphylococcus aureus using well diffusion agar. The samples included BG58S (58%SiO2, 36%CaO, 6%P2O5, BG/10CuO (58%SiO2, 26%CaO, 6%P2O5, 10%CuO, and BG/20CuO (48%SiO2, 26%CaO, 6%P2O5, 20%CuO. To evaluate their bioactivity, the prepared samples of BG/20CuO, BG/10CuO, and BG58S were immersed in simulated body fluids (SBF. The surface morphology and structure of the samples before and after immersion in the SBF were characterized using scanning electron microscopy (SEM and Fourier transform infrared (FTIR, respectively. Then, the BG/20CuO and BG/10CuO samples were loaded in clindamycin, an antibiotic widely used in the treatment of osteomyelitis, and their release profiles were studied in phosphate buffer solution. Results It was observed that the growth inhibition zone increased through clindamycin release due to the increasing CuO percentage in the nanocomposite of bioactive glass. The bioactivity of the nanocomposite/bioglass with CuO was superior to that of bioglass alone. In this study, the BG/20CuO sample showed a sustained release of clindamycin, which is sufficient for a drug delivery system. Conclusions Increasing the Cu nanoparticles in bioactive glass samples leads to the release of Cu2

  20. Bacteriophages as Bactericides in Plant Protection

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    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.

  1. Bactericidal Activity of Probiotic Agents

    Directory of Open Access Journals (Sweden)

    A.Ye. Abaturov

    2013-12-01

    Full Text Available The article grounds the symbiotic drugs tp inhibit the growth of pathogenic flora, to improve immune status, to enhance the general resistance of the organism to the pathogenic contagions.

  2. 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.

  3. Bactericidal Activity of Aqueous Acrylic Paint Dispersion for Wooden Substrates Based on TiO2 Nanoparticles Activated by Fluorescent Light

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    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.

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

    Institute of Scientific and Technical Information of China (English)

    解效白; 陈炜峰

    2012-01-01

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

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

    Science.gov (United States)

    Smalley, D L; Ourth, D D

    1979-01-01

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

  6. Electrospun biodegradable polymers loaded with bactericide agents

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

    Science.gov (United States)

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

    2011-01-01

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

  8. Bactericidal antibiotics induce programmed metabolic toxicity

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    Aislinn D. Rowan

    2016-03-01

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

  9. Antibody to a 145-kilodalton outer membrane protein has bactericidal activity and protective activity against experimental bacteremia caused by a Brazilian purpuric fever isolate of Haemophilus influenzae biogroup aegyptius. The Brazilian Purpuric Fever Study Group.

    Science.gov (United States)

    Rubin, L G; Rizvi, A

    1991-12-01

    The immunologic basis for protection against Brazilian purpuric fever, a septicemic infection associated with Haemophilus influenzae biogroup aegyptius bacteremia, is unknown. Passive immunization of infant rats with antiserum to whole bacterial cells of the homologous strain protects them from experimental bacteremia following bacterial challenge. In immunoblotting, antibody to a 145-kDa protein (P145) was present in protective antisera but not in nonprotective antisera. As judged by analysis of the antibodies eluted from whole bacterial cells and the agglutination of bacteria by antisera to P145, this protein is surface exposed. We prepared monospecific rat antisera to this protein by three methods: (i) immunization with whole bacterial cells and absorption with a Brazilian purpuric fever strain not expressing P145, (ii) immunization with gel-purified P145, and (iii) immunization with a P145-expressing transformant of a laboratory H. influenzae strain expressing this protein and absorption of the antiserum with the laboratory H. influenzae strain. These antisera had low antilipooligosaccharide antibody titers, were reactive only with P145, and had bactericidal activity in vitro. Following passive immunization, these antisera partially protected infant rats from bacteremia resulting from intraperitoneal challenge with bacteria. As assessed by immunoblotting, pooled adult human sera contained antibodies reactive with P145. Antibody to P145 may contribute to protection against Brazilian purpuric fever.

  10. 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

  11. Biosynthesis of Antitumoral and Bactericidal Sanguinarine

    Science.gov (United States)

    García, Víctor P.; Valdés, F.; Martín, R.; Luis, J. C.; Afonso, A. M.; Ayala, J. H.

    2006-01-01

    A simple, rapid, and reliable TLC method for the separation and determination of sanguinarine has been established. This intensively studied biologically active alkaloid has a wide range of potentially useful medicinal properties, such as antimicrobial, antiinflammatory, and antitumoral activities. Sanguinarine has also been incorporated into expectorant mixtures and has a strong bactericidal effect upon gram-positive bacteria, particularly Bacillus anthracis and staphylococci. These medicinal properties are due to the interaction of sanguinarine with DNA. A fibre-optic-based fluorescence instrument for in situ scanning was used for quantitative measurements. The sanguinarine was determined over the range 5–40 ng and a detection limit of 1.60 ng. The method was applied to the quantification of sanguinarine in tissue culture extracts of Chelidonium majus L. PMID:16883053

  12. 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.

  13. Bacteria survival probability in bactericidal filter paper.

    Science.gov (United States)

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

    2014-05-01

    Bactericidal filter papers offer the simplicity of gravity filtration to simultaneously eradicate microbial contaminants and particulates. We previously detailed the development of biocidal block copolymer micelles that could be immobilized on a filter paper to actively eradicate bacteria. Despite the many advantages offered by this system, its widespread use is hindered by its unknown mechanism of action which can result in non-reproducible outcomes. In this work, we sought to investigate the mechanism by which a certain percentage of Escherichia coli cells survived when passing through the bactericidal filter paper. Through the process of elimination, the possibility that the bacterial survival probability was controlled by the initial bacterial load or the existence of resistant sub-populations of E. coli was dismissed. It was observed that increasing the thickness or the number of layers of the filter significantly decreased bacterial survival probability for the biocidal filter paper but did not affect the efficiency of the blank filter paper (no biocide). The survival probability of bacteria passing through the antibacterial filter paper appeared to depend strongly on the number of collision between each bacterium and the biocide-loaded micelles. It was thus hypothesized that during each collision a certain number of biocide molecules were directly transferred from the hydrophobic core of the micelle to the bacterial lipid bilayer membrane. Therefore, each bacterium must encounter a certain number of collisions to take up enough biocide to kill the cell and cells that do not undergo the threshold number of collisions are expected to survive. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Stephen Haswell

    2012-04-01

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

  16. Biodegradable drug-eluting nanofiber-enveloped implants for sustained release of high bactericidal concentrations of vancomycin and ceftazidime: in vitro and in vivo studies.

    Science.gov (United States)

    Hsu, Yung-Heng; Chen, Dave Wei-Chih; Tai, Chun-Der; Chou, Ying-Chao; Liu, Shih-Jung; Ueng, Steve Wen-Neng; Chan, Err-Cheng

    2014-01-01

    We developed biodegradable drug-eluting nanofiber-enveloped implants that provided sustained release of vancomycin and ceftazidime. To prepare the biodegradable nanofibrous membranes, poly(D,L)-lactide-co-glycolide and the antibiotics were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. They were electrospun into biodegradable drug-eluting membranes, which were then enveloped on the surface of stainless plates. An elution method and a high-performance liquid chromatography assay were employed to characterize the in vivo and in vitro release rates of the antibiotics from the nanofiber-enveloped plates. The results showed that the biodegradable nanofiber-enveloped plates released high concentrations of vancomycin and ceftazidime (well above the minimum inhibitory concentration) for more than 3 and 8 weeks in vitro and in vivo, respectively. A bacterial inhibition test was carried out to determine the relative activity of the released antibiotics. The bioactivity ranged from 25% to 100%. In addition, the serum creatinine level remained within the normal range, suggesting that the high vancomycin concentration did not affect renal function. By adopting the electrospinning technique, we will be able to manufacture biodegradable drug-eluting implants for the long-term drug delivery of different antibiotics.

  17. Exploring a new phenomenon in the bactericidal response of TiO2 thin films by Fe doping: Exerting the antimicrobial activity even after stoppage of illumination

    Science.gov (United States)

    Naghibi, Sanaz; Vahed, Shohreh; Torabi, Omid; Jamshidi, Amin; Golabgir, Mohammad Hossein

    2015-02-01

    Antibacterial properties of Fe-doped TiO2 thin films prepared on glass by the sol-gel hot-dipping technique were studied. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, scanning probe microscopy and X-ray photoelectron spectroscopy. The photocatalytic activities were evaluated by measuring the decomposition rate of methylene blue under ultra violet and visible light. The antibacterial properties of the coatings were investigated against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisia and Aspergillus niger. The principle of incubation methods was also discussed. The results indicated that Fe doping of thin films eventuated in high antibacterial properties under visible light and this performance remained even after stoppage of illumination. This article tries to provide some explanation for this fact.

  18. Comparative study on bactericidal activity of benzalkonium chloride and dodecyl two propylene triamine%苯扎氯铵与十二烷基二亚丙三胺杀菌活性比较研究

    Institute of Scientific and Technical Information of China (English)

    张丽蓉; 陈维; 邓金花; 宋金武

    2016-01-01

    Objective To compare bactericidal activity of benzalkonium chloride and dodecyl two propylene triamine.Methods Suspension quantitative germicidal test and antibacterial ring test were used to study bactericidal activity of benzalkonium chloride and dodecyl two propylene triamine.Results The average killing logarithm values of Pseudomonas aeruginosa,Escherichia coli and Staphylococcus aureus exposed to the concentration of 500 mg/L of the benzalkonium chloride for 1 min were 5.18,7.02 and 7.13 respectively,the average killing logarithm value of Candida albicans was 4.48.The average killing logarithm values of P.aeruginosa,E.coli and S.aureus exposed to the concentration of 500 mg/L of the dodecyl two propylene triamine for 1 min were 5.84,7.32 and 7.13 respectively,the average killing logarithm value of C.albicans was 4.94.Concentration was 50 mg/L,the antibacterial ring diameters of benzalkonium chloride and dodecyl two propylene triamine were 8.3 mm and 8.2 mm respectively.Conclusion The bactericidal effect of dodecyl two propylene triamine is better than that of benzalkonium chloride,there was no significant difference in antibacterial effect.%目的 比较苯扎氯铵与十二烷基二亚丙三胺的杀菌活性.方法 采用悬液定量杀菌试验和抑菌环试验方法,对苯扎氯铵和十二烷基二亚丙三胺的杀菌活性进行比较研究.结果 用含500 mg/L的苯扎氯铵作用1 min,对铜绿假单胞菌、大肠杆菌和金黄色葡萄球菌的平均杀灭对数值分别为5.18、7.02和7.13,对白色念珠菌的平均杀灭对数值为4.48.用含500 mg/L的十二烷基二亚丙三胺作用1 min,对铜绿假单胞菌、大肠杆菌和金黄色葡萄球菌的平均杀灭对数值分别为5.84、7.32和7.13,对白色念珠菌的平均杀灭对数值为4.94.浓度为50 mg/L时,苯扎氯铵与十二烷基二亚丙三胺的抑菌环直径分别为8.3 mm和8.2 mm.结论 十二烷基二亚丙三胺的杀菌效果优于苯扎氯铵,抑菌效果无显著差异.

  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. 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

  1. Easy and Rapid Purification of Highly Active Nisin

    Directory of Open Access Journals (Sweden)

    André Abts

    2011-01-01

    Full Text Available Nisin is an antimicrobial peptide produced and secreted by several L. lactis strains and is specifically active against Gram-positive bacteria. In previous studies, nisin was purified via cation exchange chromatography at low pH employing a single-step elution using 1 M NaCl. Here, we describe an optimized purification protocol using a five-step NaCl elution to remove contaminants. The obtained nisin is devoid of impurities and shows high bactericidal activity against the nisin-sensitive L. lactis strain NZ9000. Purified nisin exhibits an IC50 of ~3 nM, which is a tenfold improvement as compared to nisin obtained via the one-step elution procedure.

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

    Science.gov (United States)

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

    2017-03-01

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

  3. Human milk bactericidal properties: effect of lyophilization and relation to maternal factors and milk components.

    Science.gov (United States)

    Salcedo, Jaime; Gormaz, Maria; López-Mendoza, Maria C; Nogarotto, Elisabetta; Silvestre, Dolores

    2015-04-01

    Lyophilization appears to be a viable method for storing human milk, assuring no microbiological contamination and preserving its health benefits and antibacterial properties. The aim of the study is to evaluate and compare the effects of different storage methods (lyophilization and freezing at -20°C and -80°C) and maternal factors (gestational length or time postpartum) upon the microbiological contents and bactericidal activity of human milk. The possible relation between bactericidal activity and the content of certain nutrients and functional components is also investigated. Microbiological content, bactericidal activity, sialic acid, and ganglioside contents, as well as protein, fat, and lactose concentrations were assessed in 125 human milk samples from 65 healthy donors in the Human Milk Bank of La Fe (Valencia, Spain). Lyophilization and storage at -80°C significantly reduced the content of mesophilic aerobic microorganisms and Staphylococcus epidermidis when compared with storage at -20°C. Bactericidal activity was not significantly modified by lyophilization when compared with freezing at either -20°C or -80°C. Bactericidal activity was not correlated with fat, protein, or lactose content, but was significantly correlated to ganglioside content. The bactericidal activity was significantly greater (P milk and in milk from women with term delivery than in milk from early lactation (days 1-7 postpartum) and milk from women with preterm delivery, respectively. Lyophilization and storage at -80°C of human milk yields similar results and are superior to storage at -20C with regard to microbial and bactericidal capacities, being a feasible alternative for human milk banks.

  4. Evaluation of bactericidal activity of TiO2 photocatalysts: a comparative study of laboratory-made and commercial TiO2 samples

    Directory of Open Access Journals (Sweden)

    Uraiwan Sirimahachai

    2009-11-01

    Full Text Available Titanium dioxide photocatalysts were synthesized by sol-gel process, by varying the reaction conditions, acids, water content, and trivalent (Al, B dopants. The characterizations of products were determined by XRD, SEM, BET, and UV-vis spectroscopy. The samples were mainly amorphous with a small amount of anatase, rutile, or a mixture of anatase and rutile, with a crystallite sizes of about 5-10 nm. The antibacterial activity of the synthesized TiO2 samples were investigated qualitatively and semi-quantitatively. Five types of bacteria, Escherichia coli ATCC25922, Psudomonas aeruginosa ATCC27853,Bacillus subtilis BGA, Staphylococcus aureus ATCC25923, and methicillin-resistant S. aureus (MRSA DMST 2054, were used for the inactivation experiment employing the agar dilution method. All the synthesized samples showed inactivation activity with varying degree of efficiency. Two of them showed a much higher activity than Degussa P25.

  5. 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

  6. 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

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

    Science.gov (United States)

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

    2013-10-01

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

  8. 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.

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

    Science.gov (United States)

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

    2013-04-01

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

  10. Bactericidal 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.

  11. Neutrophil and Monocyte Bactericidal Responses to 10 Weeks of Low-Volume High-Intensity Interval or Moderate-Intensity Continuous Training in Sedentary Adults

    Directory of Open Access Journals (Sweden)

    David B. Bartlett

    2017-01-01

    Full Text Available Neutrophils and monocytes are key components of the innate immune system that undergo age-associated declines in function. This study compared the impact of high-intensity interval training (HIIT and moderate-intensity continuous training (MICT on immune function in sedentary adults. Twenty-seven (43 ± 11 years healthy sedentary adults were randomized into ten weeks of either a HIIT (>90% maximum heart rate or MICT (70% maximum heart rate group training program. Aerobic capacity (VO2peak, neutrophil and monocyte bacterial phagocytosis and oxidative burst, cell surface receptor expression, and systemic inflammation were measured before and after the training. Total exercise time commitment was 57% less for HIIT compared to that for MICT while both significantly improved VO2peak similarly. Neutrophil phagocytosis and oxidative burst and monocyte phagocytosis and percentage of monocytes producing an oxidative burst were improved by training similarly in both groups. Expression of monocyte but not neutrophil CD16, TLR2, and TLR4 was reduced by training similarly in both groups. No differences in systemic inflammation were observed for training; however, leptin was reduced in the MICT group only. With similar immune-enhancing effects for HIIT compared to those for MICT at 50% of the time commitment, our results support HIIT as a time efficient exercise option to improve neutrophil and monocyte function.

  12. Neutrophil and Monocyte Bactericidal Responses to 10 Weeks of Low-Volume High-Intensity Interval or Moderate-Intensity Continuous Training in Sedentary Adults.

    Science.gov (United States)

    Bartlett, David B; Shepherd, Sam O; Wilson, Oliver J; Adlan, Ahmed M; Wagenmakers, Anton J M; Shaw, Christopher S; Lord, Janet M

    2017-01-01

    Neutrophils and monocytes are key components of the innate immune system that undergo age-associated declines in function. This study compared the impact of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on immune function in sedentary adults. Twenty-seven (43 ± 11 years) healthy sedentary adults were randomized into ten weeks of either a HIIT (>90% maximum heart rate) or MICT (70% maximum heart rate) group training program. Aerobic capacity (VO2peak), neutrophil and monocyte bacterial phagocytosis and oxidative burst, cell surface receptor expression, and systemic inflammation were measured before and after the training. Total exercise time commitment was 57% less for HIIT compared to that for MICT while both significantly improved VO2peak similarly. Neutrophil phagocytosis and oxidative burst and monocyte phagocytosis and percentage of monocytes producing an oxidative burst were improved by training similarly in both groups. Expression of monocyte but not neutrophil CD16, TLR2, and TLR4 was reduced by training similarly in both groups. No differences in systemic inflammation were observed for training; however, leptin was reduced in the MICT group only. With similar immune-enhancing effects for HIIT compared to those for MICT at 50% of the time commitment, our results support HIIT as a time efficient exercise option to improve neutrophil and monocyte function.

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

    Directory of Open Access Journals (Sweden)

    Sayedeh Fatemeh Shaffiey

    2014-04-01

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

  14. 衍生自人ⅡA型磷脂酶A2碳末端的多肽C-26杀菌作用研究%Study on Bactericidal Activity of the Polypeptide C-26 Derived from C-terminal of Human Group Ⅱ A Phospholipase A2

    Institute of Scientific and Technical Information of China (English)

    何睿林; 梁宁生

    2011-01-01

    OBJECTIVE: To observe the bactericidal activity of the polypeptide C-26 which derives from C-terminal of human group H A phospholipase A2(group II A PLA2). METHODS: According to C-terminal 26 amino acid residues sequence of human group HA phospholipase A2, a piece of polypeptide C-26 had been synthesized. 6 kinds of bacterial strains (Staphylococcus aure-us, Bacillus subtilis, Bacillus anthrax, Escherichia coli, Bacillus proteus and Bacillus pyocyaneus) were incubated with different concentration of polypeptide C-26 at 37 ℃ for 2 h in a water bath respectively. After incubated for 18~24 hours in the thermostat-ed container at 37 t, the colony formed unit was counted and the bactericidal rates of polypeptide C-26 were calculated. RESULTS: The polypeptide C-26 possessed potent bactericidal activity to the gram-positive(G') bacteria, such as Staphylococcus aure-us, Bacillus subtilis, Bacillus anthrax, the concentration of polypeptide C-26 against 99% bacteria ranged 250~l 000 mg·L-1; it possessed weak bactericidal activity to the gram-negative (G-) bacteria, such as Escherichia coli, Bacillus proteus,Bacillus pyocyaneus. The bactericidal rate of polypeptide C-26 with the concentration of 500 mg·L-1 were 41%~52%. CONCLUSION: The polypeptide C-26 which derives from C-terminal of human group ⅡA PLA2 possesses bactericidal activity, it is speculated that the polypeptide might have similar bactericidal mechanism as human group ⅡA PLA2 and the other antibacterial peptides.%目的:考察衍生自人ⅡA型磷脂酶A2(ⅡA型PLA2)碳(C)末端的多肽C-26对不同细菌的体外杀菌作用.方法:根据人ⅡA型PLA2 C末端26个氨基酸残基的顺序,合成多肽C-26.采用琼脂铺板计数法,将不同浓度的多肽C-26分别与6种细菌(金黄色葡萄球菌、炭疽杆菌、枯草杆菌、大肠杆菌、变形杆菌和绿脓杆菌)在37℃孵育2 h,然后铺板并置于37℃恒温箱培养18~24 h,记录每一琼脂板上的菌落形

  15. BACTERICIDAL ACTIVITY OF HUMAN SERA AGAINST ...

    African Journals Online (AJOL)

    hi-tech

    2000-12-12

    Dec 12, 2000 ... Immunoglobulin in the resistance or susceptibility of Salmonella typhi and Salmonella paratyphi A,B,C ... individual to Salmonella typhi and paratyphi infections. Individuals of ..... human immunodeficiency virus. J. Immuno.

  16. Salicylanilide carbamates: Promising antibacterial agents with high in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Zadrazilova, Iveta; Pospisilova, Sarka; Masarikova, Martina; Imramovsky, Ales; Ferriz, Juana Monreal; Vinsova, Jarmila; Cizek, Alois; Jampilek, Josef

    2015-09-18

    A series of twenty-one salicylanilide N-alkylcarbamates was assessed for novel antibacterial characteristics against three clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus ATCC 29213 as the reference and quality control strain. The minimum inhibitory concentration was determined by the broth dilution micro-method with subsequent subcultivation of aliquots to assess minimum bactericidal concentration. The bactericidal kinetics was established by time-kill assay. Ampicillin, ciprofloxacin and vancomycin were used as reference antibacterial drugs. All the tested compounds exhibited highly potent anti-MRSA activity (⩽ 0.008-4 μg/mL) comparable or up to 250× higher than that of vancomycin, the standard in the treatment of serious MRSA infections. 4-Chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl butylcarbamate and 4-chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl ethylcarbamate were the most active compounds. In most cases, compounds provided reliable bacteriostatic activity, except for 4-chloro-2-(4-chlorophenylcarbamoyl)phenyl decylcarbamate exhibiting bactericidal effect at 8h (for clinical isolate of MRSA 63718) and at 24h (for clinical isolates of MRSA SA 630 and MRSA SA 3202) at 4× MIC. Structure-activity relationships are discussed.

  17. 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.

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

    Science.gov (United States)

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

    1997-11-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Bactericidal behavior of Cu-containing stainless steel surfaces

    Science.gov (United States)

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

    2012-10-01

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

  1. 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

    2016-04-01

    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 (peffect 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 lack of in vitro killing by anti-LPS antibodies from a minority of HIV-infected individuals with impaired immune homeostasis.

  2. 碳纤维复合涂层在高压脉冲电场下的杀菌性能研究%Research on Bactericidal Properties of Carbon Fiber Composite Coatings in High-voltage Pulse Electric Field

    Institute of Scientific and Technical Information of China (English)

    杨鹏鹏; 吴进怡; 柴柯; 林海强; 宋春蕾

    2015-01-01

    ABSTRACT:Objective To explore the inhibition effects and mechanism of high-voltage pulsed electric field ( HPEF) in marine environment on microbial fouling. Methods Carbon fiber / epoxy composite anti-corrosion coating was prepared by brushing meth-od, and the effects of the carbon fiber length and content on the dielectric properties and surface energy of the composite coating as well as the bactericidal performance of the carbon fiber composite coating in high-voltage pulsed electric field. Results The results showed that the carbon fiber length and content were the main factors affecting the dielectric properties of the composite coating un-der high frequency. With the increase of electric field intensity and frequency within the set range, the sterilization rate of the coat-ing obviously increased, while with the increase of duty cycle, the sterilization rate of the coating first increased and then decreased and finally tended to be stable. When the duty cycle was 0. 5, the maximum sterilization rate of 99. 8% was reached. Conclusion The composite coating with a doping content of 0. 1% 5 mm carbon fiber had excellent dielectric properties. High-voltage pulsed e-lectric field had a good killing effect on bacteria and the sterilization rate of the coating could reach 99. 97%.%目的:研究海洋环境下高压脉冲电场对微生物污损的抑制效果和机理。方法采用刷涂法制备碳纤维/环氧防腐涂料复合涂层,研究碳纤维长度和含量对复合涂层的介电性能和表面能的影响以及碳纤维复合涂层在高压脉冲电场作用下的杀菌性能。结果高频电场下,碳纤维长度和含量是影响复合涂层介电性能的主要因素,随着电场强度、频率在设定范围内增加,涂层的杀菌率显著增大;而随占空比的增大,涂层的杀菌率呈先增后减最后趋于平缓的趋势,占空比为0.5时涂层的杀菌率最高达99.8%。结论掺杂0.1%(质量分数)5 mm碳纤维的

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Sarah E Clark

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

  5. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

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

    Directory of Open Access Journals (Sweden)

    de Oliveira MG

    2012-11-01

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

  9. Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics.

    Science.gov (United States)

    Li, Zhonglei; Tan, Jun; Shao, Lei; Dong, Xiaojing; Ye, Richard D; Chen, Daijie

    2017-05-01

    Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2', 7'-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics. Copyright © 2017 Elsevier GmbH. All rights reserved.

  10. Residual water bactericide monitor development program

    Science.gov (United States)

    1973-01-01

    A silver-ion bactericidal monitor is considered for the Space Shuttle Potable Water System. Potentiometric measurement using an ion-selective electrode is concluded to be the most feasible of available techniques. Four commercially available electrodes and a specially designed, solid-state, silver-sulfide electrode were evaluated for their response characteristics and suitability for space use. The configuration of the solid-state electrode with its Nernstian response of 10 to 10,000 ppb silver shows promise for use in space. A pressurized double-junction reference electrode with a quartz-fiber junction and a replaceable bellows electrolyte reservoir was designed verification-tested, and paired with a solid-state silver-sulfide electrode in a test fixture.

  11. 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.

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

    Science.gov (United States)

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

    2010-09-01

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

  13. 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

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

    Science.gov (United States)

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

    2016-01-01

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

  15. 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.

  16. 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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  18. 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

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

    OpenAIRE

    Thomassen, M J; Demko, C A

    1981-01-01

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

  20. 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

    mechanisms affecting antibiotic effectiveness on biofilms remain unclear, accumulating evidence suggests that the efficacy of several bactericidal antibiotics such as ciprofloxacin is enhanced by stimulation of the aerobic respiration of pathogens, and that lack of O2 increases their tolerance. Reoxygenation...... of O2-depleted biofilms may thus improve susceptibility to ciprofloxacin possibly by restoring aerobic respiration. We tested such a strategy using reoxygenation of O2-depleted P. aeruginosa strain PAO1 agarose-embedded biofilms by hyperbaric oxygen treatment (HBOT) (100% O2, 2.8bar), enhancing...... the diffusive supply for aerobic respiration during ciprofloxacin treatment. This proof-of-principle study demonstrates that biofilm reoxygenation by HBOT can significantly enhance the bactericidal activity of ciprofloxacin on P. aeruginosa. Combining ciprofloxacin treatment with HBOT thus clearly has potential...

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

    Science.gov (United States)

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

    2015-11-03

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

  2. The preparation of highly active antimicrobial silver nanoparticles by an organometallic approach

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Eduardo J; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M; Monge, Miguel [Departamento de Quimica Grupo de SIntesis Quimica de La Rioja, UA-CSIC, Universidad de La Rioja, Complejo CientIfico-Tecnologico, E-26004 Logrono (Spain); Laguna, Antonio [Departamento de Quimica Inorganica, Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain); Torres, Carmen [Departamento de Agricultura y Alimentacion, Universidad de La Rioja, Complejo Cientifico-Tecnologico, E-26004 Logrono (Spain)], E-mail: eduardo.fernandez@unirioja.es

    2008-05-07

    Silver nanoparticles of small size with a high surface to volume ratio have been prepared using an organometallic approach. For this, the complex NBu{sub 4}[Ag(C{sub 6}F{sub 5}){sub 2}] has been treated with AgClO{sub 4} in a 1:1 molar ratio, giving rise to the nanoparticle precursor [Ag(C{sub 6}F{sub 5})] in solution. Addition of one equivalent of hexadecylamine (HDA) and 5 h of reflux in toluene leads to a deep yellow solution containing monodisperse silver nanoparticles (Ag NPs) of ca. 10 nm. This approach leads to nanoparticles with almost uncontaminated surfaces which make them very reactive. Antimicrobial studies show that these nanoparticles are very active as antimicrobial agents. Very low concentrations between 12 and 25 {mu}g ml{sup -1} of Ag NPs are enough to produce bacteriostatic and bactericidal effectiveness.

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

    Science.gov (United States)

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

    1972-02-01

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

  4. High-Activity Dealloyed Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kongkanand, Anusorn [General Motors LLC, Pontiac, MI (United States)

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  5. 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.

  6. [Study on synergistic effect of bactericidal effect of chlorine dioxide solution by surfactant].

    Science.gov (United States)

    Wang, Kuitao; Tian, Vuena; Gu, Na; Zhang, Congjing; Niu, Jiajing

    2013-03-01

    To study the effect of gemini fluorocarbon, sodium p-perfluorous nonenoxybenzene sulfonate and sodium dodecyl sulfate on the chlorine dioxide solution sterilization to object surface. Pure chlorine dioxide solution as the reference disinfectant, carrier quantitative bactericidal test and simulated test on-site were used to carry out laboratory observation according to The disinfection technical specifications (2002). Carrier quantitative bactericidal test showed that the addition dosage of gemini fluoronates, sodium dodecyl sulfate surfactant and perfluorinated the nonene oxy benzene sulfonate in disinfectant solution were 60, 60 and 40 mg/L respectively, the killing log value of Staphylococcus aureus exposed to the disinfectant solution containing chlorine dioxide 50 mg/L for 10 mm were all more than 3; and the addition dosage of gemini fluorinates, sodium dodecyl sulfate and perfluorinated the nonene oxy benzene sulfonate in disinfectant solution were 60 mg/L, the killing log value of Escherichia coli exposed to the disinfectant solution containing chlorine dixoxide 20 mg/L for 10 min were all more than 3. The bactericidal effect of the mixture use of surfactant and chlorine dioxide was better than the single use of chlorine dioxide. The simulated test on-site showed that the killing log value of Escherichia coli exposed to the disinfectant solution containing perfluorinated the nonene oxy benzene sulfonate 40 mg/L and chlorine dioxide 20 mg/L for 15 min was more than 3. Surface active agent on germicidal efficacy of chlorine dioxide solution had synergistic action.

  7. Enhanced bactericidal action of acidified sodium chlorite caused by the saturation of reactants.

    Science.gov (United States)

    Kim, N H; Park, T H; Rhee, M S

    2014-06-01

    Factors affecting the antibacterial action of acidified sodium chlorite (ASC), a widely used disinfectant, have not been determined. This study investigated the significant factors suggesting efficient production method to maximize bactericidal action of ASC. The effects of (i) preparation procedures (total three methods); (ii) initial concentrations of reactants: sodium chlorite (SC) and citric acid (CTA) (up to maximum solubility of each reactant) and (iii) final pH values (3·0 and 2·5) to the bactericidal action of ASC were investigated with a fixed final concentration of SC (10 ppm) using various foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus). The antimicrobial compounds produced and the bactericidal effects depended on the preparation procedure and the initial concentrations of the reactants. The ASC prepared by premixing highly concentrated reactants (in particular > 40%) followed by dilution (dilution after reaction, DAR) was more effective in inactivating foodborne pathogens, and it produced higher antimicrobial compound (Cl(2) and ClO(2)) yields than the other procedures. A 5-min treatment with ASC, produced using the other procedures, resulted in a reduction of < 3·5 log CFU ml(-1) (Gram positive = 0·18-0·78; Gram negative = 0·03-3·49 log CFU ml(-1)), whereas ASC produced with the DAR procedure using the saturated reactants completely inactivated all of the test pathogens within 5 min without recovery (initial concentration = 6·94-7·08 log CFU ml(-1)). The ASC production with the DAR procedure using the saturated reactants maximizes both the antimicrobial compound yields and bactericidal effects of the ASC solutions. This study will contribute to increase the efficiency of ASC treatments for disinfections reducing the effective SC concentrations for industrial use. © 2014 The Society for Applied Microbiology.

  8. Bactericidal Effect of Gold-Chitosan Nanocomposites in Coculture Models of Pathogenic Bacteria and Human Macrophages.

    Science.gov (United States)

    Mendoza, Gracia; Regiel-Futyra, Anna; Andreu, Vanesa; Sebastián, Víctor; Kyzioł, Agnieszka; Stochel, Grażyna; Arruebo, Manuel

    2017-05-31

    The ability of pathogenic bacteria to develop resistance mechanisms to avoid the antimicrobial potential of antibiotics has become an increasing problem for the healthcare system. The search for more effective and selective antimicrobial materials, though not harmful to mammalian cells, seems imperative. Herein we propose the use of gold-chitosan nanocomposites as effective bactericidal materials avoiding damage to human cells. Nanocomposites were obtained by taking advantage of the reductive and stabilizing action of chitosan solutions on two different gold precursor concentrations. The resulting nanocomposites were added at different final concentrations to a coculture model formed by Gram-positive (Staphylococcus aureus) or Gram-negative (Escherichia coli) bacteria and human macrophages. Gold-chitosan colloids exhibited superior bactericidal ability against both bacterial models without showing cytotoxicity on human cells at the concentrations tested. Morphological and in vitro viability studies supported the feasibility of the infection model here described to test novel bactericidal nanomaterials. Flow cytometry and scanning electron microscopy analyses pointed to the disruption of the bacterial wall as the lethal mechanism. Data obtained in the present study suggest that gold-chitosan nanocomposites are powerful and promising nanomaterials for reducing bacteria-associated infections, respecting the integrity of mammalian cells, and displaying high selectivity against the studied bacteria.

  9. Effects of interleukin-1O on phagocytosis and bactericidal activity of neutrophils in mouse model%白细胞介素-10对小鼠中性粒细胞吞噬和杀菌活性的影响

    Institute of Scientific and Technical Information of China (English)

    赵修春; 徐凤珍; 李柏青

    2011-01-01

    Objective:To investigate the effects of inteluekin-10( IL-10 ) on the neutrophil phagocytosis and bactericidal activity in mouse model. Methods:Whole blood of mice was pretreated with IL-10 at different concentrations, ranged from 1 pg to 100 ng/ml for 2 hours at 37 ℃, and then incubated with FITC labeled E. coli at 37 ℃ for 15 minutes. After lysing red blood cells the neutrophil phagocytosis was measured by flow cytometry. In the bactericidal assay,whole blood of mice pretreated with IL-10( 0.1 and 1 ng/ml )for 2 hours at 37 ℃ was incubated with E. coli in water bath at 37 ℃ for 1 hour, and then cultured on agar plates. The number of colonies was counted and the inhibitory effect of IL-10 on killing activity was calculated. Results:The reduced rates of phagocytosis was ( 15.87 ± 14.25 )% only in the group that pretreated with IL-10 at 1 ng/ml,but with no significance( P >0.05 ). The relative rates of bactericidal activity of neutrophil in the groups of IL-10 at 0.1 ng/ml and 1 ng/ml were significanty reduced( 39.59 ± 37.36 )% and ( 42.28 ± 22.24 )% ( P < 0.05 ), respectively. Conclusions: IL-10 slightly decreases the phagocytosis of the neutrophils, but potently suppresses the bactericidal activity of neutrophils. IL-10 is capabling of down-regulating non-specific immunity.%目的:探讨白细胞介素-10(IL-10)对中性粒细胞(PMN)吞噬和杀菌活性的影响,以了解IL-10对非特异性免疫的作用机制.方法:小鼠麻醉后从眼球取血,与不同浓度IL-10在37 ℃水浴中作用2 h,然后加FITC标记大肠埃希菌,置37 ℃水浴中15 min,溶血剂去除红细胞,流式细胞仪检测各IL-10浓度组PMN的吞噬率.小鼠麻醉后局部消毒,摘眼球,无菌方法取血.与不同浓度IL-10 在37 ℃下作用2 h,然后加大肠埃希菌置37 ℃水浴1 h,同时设PMN杀菌0 min组、无IL-10的PMN杀菌对照组,各组样品作适当稀释后接种琼脂平板,最后观察各组菌落数,与对照组比较,计算IL-10对

  10. Efficiency of Chlorine Dioxide as a Bactericide1

    Science.gov (United States)

    Benarde, Melvin A.; Israel, Bernard M.; Olivieri, Vincent P.; Granstrom, Marvin L.

    1965-01-01

    We found chlorine dioxide to be a more effective disinfectant than chlorine in sewage effluent at pH 8.5. Chlorine dioxide was also found to be a more stable bactericide in relation to pH in the range studied. Images Fig. 1 PMID:5325940

  11. 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.

  12. 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.

  13. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-01

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

  16. 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.

  17. Bactericidal effects of triclosan in soap both in vitro and in vivo.

    Science.gov (United States)

    Kim, S A; Moon, H; Lee, K; Rhee, M S

    2015-12-01

    On December 2013, the US FDA proposed a rule stating that manufacturers must provide data to demonstrate that antibacterial soap is more effective than plain soap or water. The objective of the present study was to examine the in vitro and in vivo bactericidal effect of triclosan (the most widely used antiseptic agent in soap) in soap. Twenty bacterial strains (proposed by the FDA) were exposed to plain and antibacterial soaps (the same formulation as plain soap, but containing 0.3% triclosan) for 20 s at 22°C (room temperature) and 40°C (warm temperature). The temperature and time were selected to simulate the hand washing conditions and procedures used by consumers. The triclosan concentration of 0.3% is the maximum allowed by law. The decontamination efficacy of plain soap and antibacterial soap was also examined in vivo: the hands of volunteers were artificially inoculated with Serratia marcescens. There was no significant difference (P > 0.05) in bactericidal activity between plain soap and antibacterial soap at either test temperature. However, antibacterial soap showed significantly greater bactericidal effects after 9 h. These results suggest that although triclosan-containing soap does have antibacterial activity, the effects are not apparent during the short time required for hand washing. Antibacterial soap containing triclosan (0.3%) was no more effective than plain soap at reducing bacterial contamination when used under 'real-life' conditions. The present study provides practical information that may prove useful for both industry and governments. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

    Science.gov (United States)

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

    2011-12-01

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

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    Wang B

    2016-12-01

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

  1. Bactericidal effects of mouth rinses on oral bacteria.

    Science.gov (United States)

    Kasuga, Y; Ikenoya, H; Okuda, K

    1997-11-01

    The bactericidal efficacy of two types of Listerine; Listerine and Cool Mint Listerine, and povidone iodine on oral microorganisms, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Helicobacter pylori and Candida albicans were examined. Most of the oral bacteria were killed completely by a 10-sec exposure to Listerine or Cool Mint Listerine. H. pylori, MRSA and C. albicans were also reduced by a 30-sec exposure to the Listerine mouth rinse. Bacteria in dental plaque were decreased by exposure to Listerine, Cool Mint Listerine, and povidone iodine for 30 seconds. Mouthwashing with Listerine for 30 seconds resulted in a decrease to approximately 1/100 of the viable bacterial counts in saliva. These bactericidal effects against bacteria in saliva and dental plaque indicated that Listerine and Cool Mint Listerine antiseptic are useful in oral cavity as antiseptic mouth rinses.

  2. 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.

  3. 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.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

    Bacha, Abir Ben

    2014-10-01

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

  6. Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens

    NARCIS (Netherlands)

    Kwakman, P.H.S.; Boer, den L.; Ruyter-Spira, C.; Creemers-Molenaar, T.; Helsper, J.P.F.G.; Vandenbroucke-Grauls, C.M.J.E.; Zaat, S.A.J.; Velde, te A.A.

    2011-01-01

    Honey has potent activity against both antibioticsensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We

  7. Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens

    NARCIS (Netherlands)

    P.H.S. Kwakman; L. de Boer; C.P. Ruyter-Spira; T. Creemers-Molenaar; J.P.F.G. Helsper; C.M.J.E. Vandenbroucke-Grauls; S.A.J. Zaat; A.A. te Velde

    2011-01-01

    Honey has potent activity against both antibiotic-sensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We

  8. Planning High-Risk High-Reward Activities.

    NARCIS (Netherlands)

    Casault, Sébastien

    2014-01-01

    This body of work addresses a gap in financial and economic theories related to assets that are typically associated with high uncertainty. Specifically, this thesis provides some foundational work towards a new way to quantify and explain how high-risk high-reward activities, such as exploration,

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

    OpenAIRE

    Degiacomi, Giulia; Personne, Yoann; Mondesert, Guillaume; Ge, Xueliang; Mandava, Chandra Sekhar; Hartkoorn, Ruben C.; Boldrin, Francesca; Goel, Pavitra; Peisker, Kristin; Benjak, Andrej; Barrio, Maria Belen; Ventura, Marcello; Amanda C Brown; Leblanc, Veronique; Bauer, Armin

    2016-01-01

    The lack of proper treatment for serious infectious diseases due to the emergence of multidrug resistance reinforces the need for the discovery of novel antibiotics. This is particularly true for tuberculosis (TB) for which 3.7% of new cases and 20% of previously treated cases are estimated to be caused by multi-drug resistant strains. In addition, in the case of TB, which claimed 1.5 million lives in 2014, the treatment of the least complicated, drug sensitive cases is lengthy and disagreeab...

  10. Comparative bactericidal activities of lasers operating at seven different wavelengths

    Science.gov (United States)

    Watson, Ian A.; Ward, Glenn D.; Wang, RuiKang K.; Sharp, James H.; Budgett, David M.; Stewart-Tull, Duncan E.; Wardlaw, Alastair C.; Chatwin, Christopher R.

    1996-10-01

    Seven laser instruments, delivering radiation at a selection of wavelengths in the range of 0.355 to 118 micrometers , we investigated for their ability to kill Escherichia coli as a lawn of the bacteria on nutrient agar culture plates. Easily the most effective was a 600-W CO2 laser operating at 10.6 micrometers , which produced 1.2-cm2 circular zones of sterilization at energy densities of around 8 J cm-2 in a 30-msec exposure. Circular zones with an area of 0.7 cm2 were achieved with 200 W from a Nd:YAG laser delivering 8-ms, 10-J pulses of 1.06 micrometers radiation at 20 Hz. The exposure time, however, was 16 s and the energy density was more than 240 times higher than with the CO2 laser. This difference is believed to be partly due to the much higher absorption of radiation at 10.6 micrometers , by water in the bacterial cells and the surrounding medium. Sterilization was observed after exposure to frequency- tripled Nd:YAG laser radiation at 355 nm. Lasers that were totally ineffective in killing Escherichia coli were the far infrared laser, the laser diode array, and the argon ion laser. The speed at which laser sterilization can be achieved is particularly attractive to the medical and food industries.

  11. 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.

  12. 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.

  13. Recombinant protein truncation strategy for inducing bactericidal antibodies to the macrophage infectivity potentiator protein of Neisseria meningitidis and circumventing potential cross-reactivity with human FK506-binding proteins.

    Science.gov (United States)

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

    2015-02-01

    A recombinant macrophage infectivity potentiator (rMIP) protein of Neisseria meningitidis induces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human proteins, we immunized mice with recombinant truncated type I rMIP proteins that lacked the globular domain and the signal leader peptide (LP) signal sequence (amino acids 1 to 22) and contained the His purification tag at either the N or C terminus (C-term). The immunogenicity of truncated rMIP proteins was compared to that of full (i.e., full-length) rMIP proteins (containing the globular domain) with either an N- or C-terminal His tag and with or without the LP sequence. By comparing the functional murine antibody responses to these various constructs, we determined that C-term His truncated rMIP (-LP) delivered in liposomes induced high levels of antibodies that bound to the surface of wild-type but not Δmip mutant meningococci and showed bactericidal activity against homologous type I MIP (median titers of 128 to 256) and heterologous type II and III (median titers of 256 to 512) strains, thereby providing at least 82% serogroup B strain coverage. In contrast, in constructs lacking the LP, placement of the His tag at the N terminus appeared to abrogate bactericidal activity. The strategy used in this study would obviate any potential concerns regarding the use of MIP antigens for inclusion in bacterial vaccines.

  14. Suppression of phagocytic and bactericidal functions of rat alveolar macrophages by the organic component of diesel exhaust particles.

    Science.gov (United States)

    Yin, Xuejun J; Dong, Caroline C; Ma, Jane Y C; Roberts, Jenny R; Antonini, James M; Ma, Joseph K H

    2007-05-15

    Exposure to diesel exhaust particles (DEP) was shown to increase the susceptibility of the lung to bacterial infection in rats. In this study, the effects of DEP on alveolar macrophage (AM) phagocytic and bactericidal functions and cytokine secretion by AM and lymphocytes in response to Listeria monocytogenes infection were investigated in vitro and the roles of different DEP components in these processes were compared. Exposure to DEP or the organic extracts of DEP (eDEP) significantly decreased the phagocytosis and killing of L. monocytogenes by AM obtained from normal rats. Washed DEP (wDEP) also decreased AM phagocytosis and bacterial killing to a lesser extent, whereas carbon black (CB) reduced AM phagocytosis but had no significant effect on AM bactericidal activity. DEP or eDEP concentration-dependently suppressed L. monocytogenes-induced secretion of tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-12 by AM and of IL-2 and interferon-gamma by lymphocytes obtained from L. monocytogenes-infected rats, but augmented the AM secretion of IL-10. wDEP or CB, however, exerted little or no effect on these L. monocytogenes-induced cytokines. These results provide direct evidence that DEP, through the actions of organic components, suppresses AM phagocytic and bactericidal functions in vitro. Inhibition of AM phagocytic function and alterations of AM and lymphocyte cytokine secretion by DEP and DEP organic compounds may be implicated in the diminished AM bactericidal activity and the lymphatic arm of the host immune system, thus resulting in an suppressed pulmonary clearance of L. monocytogenes and an increased susceptibility of the lung to bacterial infection.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  16. Bactericidal Kinetics of Marine-Derived Napyradiomycins against Contemporary Methicillin-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Nina M. Haste

    2011-04-01

    Full Text Available There is an urgent need for new antibiotics to treat hospital- and community-associated methicillin-resistant Staphylococcus aureus (MRSA infections. Previous work has indicated that both terrestrial and marine-derived members of the napyradiomycin class possess potential anti-staphylococcal activities. These compounds are unique meroterpenoids with unusual levels of halogenation. In this paper we report the evaluation of two previously described napyradiomycin derivatives, A80915A (1 and A80915B (2 produced by the marine-derived actinomycete, Streptomyces sp. strain CNQ-525, for their specific activities against contemporary and clinically relevant MRSA. Reported are studies of the in vitro kinetics of these chemical scaffolds in time-kill MRSA assays. Both napyradiomycin derivatives demonstrate potent and rapid bactericidal activity against contemporary MRSA strains. These data may help guide future development and design of analogs of the napyradiomycins that could potentially serve as useful anti-MRSA therapeutics.

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

    Directory of Open Access Journals (Sweden)

    Saiba Abdul Wahab Nusaiba

    2013-11-01

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

  18. 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.

  19. 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

  20. Bactericidal/permeability-increasing protein preserves leukocyte functions after major liver resection.

    Science.gov (United States)

    Wiezer, M J; Meijer, C; Sietses, C; Prins, H A; Cuesta, M A; Beelen, R H; Meijer, S; van Leeuwen, P A

    2000-08-01

    To analyze postoperative leukocyte functions in patients undergoing hemihepatectomy, and to assess the effect of treatment with the endotoxin-neutralizing agent bactericidal/permeability-increasing protein (rBPI21). Extensive liver resection is associated with a high incidence of infectious complications. Because elimination of pathogenic microorganisms occurs mainly by leukocytes, this increased rate of infections is most likely due to an impaired function of these cells. Endotoxin, translocated from the gut into the systemic circulation as a result of increased gut permeability and reduced hepatic clearance function after major liver resection, may play an important role in the impairment of posthepatectomy leukocyte function. To investigate whether hemihepatectomy results in impaired leukocyte functions and to determine the role of endotoxin in this process, leukocyte oxidative burst and leukocyte antigen expression were studied in three groups of patients: patients undergoing a hemihepatectomy and receiving rBPI21 treatment, patients undergoing hemihepatectomy and receiving placebo, and as an extra control group patients undergoing other major abdominal surgeries. Blood samples were collected before surgery, 2 hours after surgery, and at days 1, 2, 5, and 7. Phorbol myristate acetate-stimulated oxidative burst was measured using dihydrorhodamine, and leukocyte surface expression of the antigens CD11b, CD16, and CD14 was investigated by indirect immunofluorescence. Both oxidative burst and membrane surface expression were quantified by flow cytometry. An indication of the antiendotoxin effect of rBPI21 treatment was provided by assessment of plasma lipopolysaccharide binding protein (LBP) levels by enzyme-linked immunosorbent assay. The oxidative burst in the hemihepatectomized patients receiving placebo and the controls increased 2 hours after surgery, whereas it decreased in the rBPI21-treated patients, resulting in significant differences between the groups

  1. High effective silica fume alkali activator

    Indian Academy of Sciences (India)

    Vladimír Živica

    2004-04-01

    Growing demands on the engineering properties of cement based materials and the urgency to decrease unsuitable ecologic impact of Portland cement manufacturing represent significant motivation for the development of new cement corresponding to these aspects. One category represents prospective alkali activated cements. A significant factor influencing their properties is alkali activator used. In this paper we present a new high effective alkali activator prepared from silica fume and its effectiveness. According to the results obtained this activator seems to be more effective than currently used activators like natrium hydroxide, natrium carbonate, and water glass.

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

    Science.gov (United States)

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-08-21

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

  3. Development of a high-throughput opsonophagocytic assay for the determination of functional antibody activity against Streptococcus pyogenes using bioluminescence.

    Science.gov (United States)

    Lorenz, Natalie; Loh, Jacelyn M S; Moreland, Nicole J; Proft, Thomas

    2017-03-01

    The lack of standardised protocols for the assessment of functional antibodies has hindered Streptococcus pyogenes research and the development of vaccines. A robust, high throughput opsonophagocytic bactericidal assay to determine protective antibodies in human and rabbit serum has been developed that utilises bioluminescence as a rapid read out.

  4. The Inosine Monophosphate Dehydrogenase, GuaB2, Is a Vulnerable New Bactericidal Drug Target for Tuberculosis.

    Science.gov (United States)

    Singh, Vinayak; Donini, Stefano; Pacitto, Angela; Sala, Claudia; Hartkoorn, Ruben C; Dhar, Neeraj; Keri, Gyorgy; Ascher, David B; Mondésert, Guillaume; Vocat, Anthony; Lupien, Andréanne; Sommer, Raphael; Vermet, Hélène; Lagrange, Sophie; Buechler, Joe; Warner, Digby F; McKinney, John D; Pato, Janos; Cole, Stewart T; Blundell, Tom L; Rizzi, Menico; Mizrahi, Valerie

    2017-01-13

    VCC234718, a molecule with growth inhibitory activity against Mycobacterium tuberculosis (Mtb), was identified by phenotypic screening of a 15344-compound library. Sequencing of a VCC234718-resistant mutant identified a Y487C substitution in the inosine monophosphate dehydrogenase, GuaB2, which was subsequently validated to be the primary molecular target of VCC234718 in Mtb. VCC234718 inhibits Mtb GuaB2 with a Ki of 100 nM and is uncompetitive with respect to IMP and NAD(+). This compound binds at the NAD(+) site, after IMP has bound, and makes direct interactions with IMP; therefore, the inhibitor is by definition uncompetitive. VCC234718 forms strong pi interactions with the Y487 residue side chain from the adjacent protomer in the tetramer, explaining the resistance-conferring mutation. In addition to sensitizing Mtb to VCC234718, depletion of GuaB2 was bactericidal in Mtb in vitro and in macrophages. When supplied at a high concentration (≥125 μM), guanine alleviated the toxicity of VCC234718 treatment or GuaB2 depletion via purine salvage. However, transcriptional silencing of guaB2 prevented Mtb from establishing an infection in mice, confirming that Mtb has limited access to guanine in this animal model. Together, these data provide compelling validation of GuaB2 as a new tuberculosis drug target.

  5. Antileishmanial, antimicrobial and antifungal activities of some new aryl azomethines.

    Science.gov (United States)

    Al-Kahraman, Yasser M S A; Madkour, Hassan M F; Ali, Dildar; Yasinzai, Masoom

    2010-01-28

    A series of eighteen azomethines has been synthesized by the reaction of appropriate primary aromatic amines with aryl and/or heteroaryl carboxaldehydes. The synthesized azomethines have been evaluated for their in vitro antileishmanial, antibacterial and antifungal activities. The results revealed some antifungal activity of most of the synthesized compounds, whereas the antileishmaniasis activity results highlighted that all synthesized azomethines inhibited parasite growth and most of them showed highly potent action towards Leishmania major promastigotes. No remarkable bactericidal activities were observed.

  6. 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.

  7. Comparative in vitro activity of oritavancin and other agents against methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Sweeney, Debora; Shinabarger, Dean L; Arhin, Francis F; Belley, Adam; Moeck, Greg; Pillar, Chris M

    2017-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections constitute a threat to the public health due to their prevalence and associated mortality and morbidity. Several agents have been recently approved to treat MRSA skin infections including lipoglycopeptides (dalbavancin, oritavancin, and telavancin), ceftaroline, and tedizolid. This study compared the MIC, minimum bactericidal concentration (MBC), and time-kill of these agents alongside daptomycin, linezolid, and vancomycin against MRSA (n=15); meropenem, cefazolin, and nafcillin were also included against methicillin-susceptible S. aureus (MSSA [n=12]). MIC and MBC testing was conducted in accordance with Clinical and Laboratory Standards Institute guidelines, and time-kills were evaluated at multiples of the MIC and the free-drug maximum plasma concentration (fCmax) at both standard and high inoculum densities for a subset of MRSA (n=2) and MSSA (n=2). MRSA and MSSA were highly susceptible to all agents, with the lipoglycopeptides having the most potent activity by MIC50/90. All agents excluding tedizolid and linezolid were bactericidal by MBC for MRSA and MSSA, though dalbavancin and telavancin exhibited strain-specific bactericidal activity for MRSA. All agents excluding tedizolid and linezolid were bactericidal by time-kill at their respective fCmax against MRSA and MSSA at standard inoculum density, though oritavancin exhibited the most rapid bactericidal activity. Oritavancin and daptomycin at their respective fCmax maintained similar kill curves at high inoculum density. In contrast, the killing observed with other agents was typically reduced or slowed at high inoculum density. These data demonstrate the rapid bactericidal activity of oritavancin and daptomycin against S. aureus relative to other MRSA agents regardless of bacterial burden.

  8. Evidence for the presence of cell-surface-bound and intracellular bactericidal toxins in the dinoflagellate Heterocapsa circularisquama.

    Science.gov (United States)

    Cho, Kichul; Wencheng, Li; Takeshita, Satoshi; Seo, Jung-Kil; Chung, Young-Ho; Kim, Daekyung; Oda, Tatsuya

    2017-08-01

    Heterocapsa circularisquama, a harmful dinoflagellate, has multiple haemolytic toxins that are considered to be involved in the toxic mechanism against shellfish and certain species of zooplankton. To evaluate the further nature of the toxins of H. circularisquama, we investigated its effects on several species of bacteria. By colony formation assay, we found that H. circularisquama had antibacterial activity toward the marine bacterium Vibrio alginolyticus in a cell density-dependent manner. When the inoculated bacterial cells were co-cultured with H. circularisquama under dinoflagellate cell culture conditions, the bacterial growth was significantly suppressed, whereas the number of live bacterial cells increased when cultured in the medium alone. Since the cell-free culture supernatant and the ruptured dinoflagellate cell suspension showed no toxic effects on V. alginolyticus, it is speculated that direct cell-to-cell contact mediated by the live dinoflagellate cells may be the major toxic mechanism. The decrease in bactericidal activity of theca-removed dinoflagellate cells may further support this speculation. H. circularisquama also showed bactericidal activities towards Escherichia coli and Staphylococcus aureus. In the dinoflagellate/bacteria co-culture system, the number of live bacterial cells declined with increasing incubation time. Light-dependent antibacterial activity of the ruptured dinoflagellate cells against S. aureus was observed, whereas no such activity was detected against E. coli. These results suggest that intracellular photosensitising bactericidal toxins, which were previously found to be porphyrin derivatives, may have specificity towards gram-positive bacteria. Based on these results together with previous studies, it is obvious that H. circularisquama possesses antibacterial activity, which may be mediated through toxins located on its cell surface. It is likely that such toxins play a role in the defence mechanism against predators

  9. 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.

  10. 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.

  11. 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.

  12. Enclosure for handling high activity materials

    Energy Technology Data Exchange (ETDEWEB)

    Jimeno de Osso, F.

    1977-07-01

    One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-10-01

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

  15. 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

  16. 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.

  17. High-activity liquid packaging design criteria

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    In recent studies, it has been acknowledged that there is an emerging need for packaging to transport high-activity liquid off the Hanford Site to support characterization and process development activities of liquid waste stored in underground tanks. These studies have dealt with specimen testing needs primarily at the Hanford Site; however, similar needs appear to be developing at other US Department of Energy (DOE) sites. The need to ship single and multiple specimens to offsite laboratories is anticipated because it is predicted that onsite laboratories will be overwhelmed by an increasing number and size (volume) of samples. Potentially, the specimen size could range from 250 mL to greater than 50 L. Presently, no certified Type-B packagings are available for transport of high-activity liquid radioactive specimens in sizes to support Site missions.

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

    Directory of Open Access Journals (Sweden)

    Perfileva А.I.

    2016-05-01

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

  19. 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...

  20. 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...

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

    Directory of Open Access Journals (Sweden)

    Wilhelm Paulander

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

  2. 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.

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

    Science.gov (United States)

    Labro, M T; el Benna, J

    1990-10-01

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

  4. Dental adhesives with bioactive and on-demand bactericidal properties.

    Science.gov (United States)

    Welch, Ken; Cai, Yanling; Engqvist, Håkan; Strømme, Maria

    2010-05-01

    The aim of the present work was to perform the first in vitro evaluation of a new interfacial bond-promoting material-and-method concept for on-demand long term bacteria inhibition in dental restoration procedures. The bioactivity, mechanical bonding strength and photocatalytic bactericidal properties, induced by low dose ultraviolet-A (UV-A) irradiation of dental adhesives containing crystalline titania nanoparticles (NPs), were analyzed. Dental adhesives with a NP content of 20wt% were shown to be bioactive in terms of spontaneous hydroxylapatite formation upon storage in simulated body fluid and the bioactivity was found to be promoted by chemical etching of the adhesives. The mechanical bonding strength between the adhesives and a HA tooth model was shown to be unaffected by the NPs up to a NP content of 30wt%. Elimination of Staphylococcus epidermidis in contact with the adhesives was found to depend both on UV photocatalytic irradiation intensity and time. Efficient elimination of the bacteria could be achieved using a UV-A dose of 4.5J/cm(2) which is about 6 times below the safe maximum UV dose according to industry guidelines, and 20 times below the average UV-A dose received during an ordinary sun bed session. The combined features of bioactivity and on-demand bactericidal effect should open up the potential to create dental adhesives that reduce the incidence of secondary caries and promote closure of gaps forming at the interface towards the tooth via remineralization of adjacent tooth substance, as well as prevention of bacterial infections via on-demand UV-A irradiation. 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. High activity carbon sorbents for mercury capture

    Energy Technology Data Exchange (ETDEWEB)

    George G. Stavropoulos; Irene S. Diamantopoulou; George E. Skodras; George P. Sakellaropoulos [Aristotle University of Thessaloniki, Thessaloniki (Greece). Chemical Process Engineering Laboratory

    2006-07-01

    High efficiency activated carbons have been prepared for removing mercury from gas streams. Starting materials used were petroleum coke, lignite, charcoal and olive seed waste, and were chemically activated with KOH. Produced adsorbents were primarily characterized for their porosity by N{sub 2} adsorption at 77K. Their mercury retention capacity was characterized based on the breakthrough curves. Compared with typical commercial carbons, they have exhibited considerably enhanced mercury adsorption capacity. An attempt has been made to correlate mercury entrapment and pore structure. It has been shown that physical surface area is increased during activation in contrast to the mercury adsorption capacity that initially increases and tends to decrease at latter stages. Desorption of active sites may be responsible for this behavior. 10 refs., 3 figs., 1 tab.

  6. 利奈唑胺与克林霉素对耐甲氧西林金黄色葡萄球菌体外抗菌活性研究%Bactericidal activity of linezolid and clindamycin against methicillin -resistant Staphylococcus aureus in vitro

    Institute of Scientific and Technical Information of China (English)

    周家军; 王睿; 何争民; 孟祥云; 张正升; 季文军; 代文婷; 曹荣娟; 梁蓓蓓

    2015-01-01

    Objective To determinate the antibacterial activity of linezolid and clindamycin agents of clinical methicillin -resistant Staphy-lococcus aureus ( MRSA ) in vitro.Methods The minimum inhibitory concentration ( MIC ) and minimum bactericidal concentration ( MBC ) of antibacterial agents were determined by the micro broth dilution method . Results The linezolid inhibition rate was 100%when the concentration was 2 μg · mL-1 , but clindamycin concentration was 32 μg · mL-1 . The MIC range of linezolid for MRSA was 0.25 ~2.00 μg · mL-1 , MIC50 was 1 μg · mL -1 , MIC90 was 2 μg · mL-1 , MBC50 was 8 μg· mL-1 , MBC90 was 16 μg· mL -1.The MIC range of clindamycin for MRSA was 0.25 ~32.00 μg · mL-1 , MIC50 was 16 μg · mL-1 , MIC90 was 32 μg · mL-1 , MBC50 was 32 μg · mL-1 , MBC90 was >64 μg· mL-1.Conclusion Clindamycin in the treatment of MRSA infection or suspected MRSA infection must depend on drug sensi-tivity test results.Linezolid in the treatment of MRSA infection or suspec-ted MRSA infection has higher reliability .%目的:测定我院临床分离的耐甲氧西林金黄色葡萄球菌( MRSA)对利奈唑胺与克林霉素的体外抗菌活性。方法用微量肉汤稀释法,测定抗菌药物的最低抑菌浓度( MIC )和最低杀菌( MBC )浓度。结果利奈唑胺在浓度为2μg· mL-1时的抑菌率为100%,而克林霉素抑菌率为100%时浓度为32μg· mL-1。利奈唑胺对 MRSA 的 MIC 为0.25~2.00μg · mL-1, MIC50为1μg· mL-1,MIC90为2μg · mL-1, MBC50和 MBC90分别为8μg · mL-1和16μg· mL-1。克林霉素对 MRSA 的 MIC 为0.25~32μg · mL-1, MIC50为16μg· mL-1,MIC90为32μg · mL-1, MBC50和 MBC90分别为32μg · mL-1和>64μg· mL-1。结论克林霉素在治疗MRSA感染或疑似MRSA感染时要以药敏结果为依据,而利奈唑胺用于MRSA感染或疑似MRSA感染的治疗时可靠性更高。

  7. Size tuning of Ag-decorated TiO₂ nanotube arrays for improved bactericidal capacity of orthopedic implants.

    Science.gov (United States)

    Esfandiari, N; Simchi, A; Bagheri, R

    2014-08-01

    Surface modification of orthopedic implants using titanium dioxide nanotubes and silver nanoparticles (SNs) is a promising approach to prevent bacteria adhesion, biofilm formation, and implant infection. Herein, we utilized a straightforward and all-solution process to prepare silver-decorated TiO2 nanotube arrays with surface density of 10(3) to 10(4) per µm(2). With controlling the synthesis conditions, hexagonal closed-packed nanotubes with opening diameter of 30-100 nm that are decorated with SNs with varying sizes (12-40 nm) were prepared. Various analytical techniques were utilized to characterize the size, morphology, distribution, valance state, surface roughness, and composition of the prepared antibacterial films. The bactericidal capacity of the films were studied on Escherichia coli (E. coli) by drop-test method and correlated with the size and percentage of Ag as well as the surface density of TiO2 nanotube arrays. Synergetic effect of TiO2 nanotubes and SNs on the antibacterial activity of the composite films is shown. The bactericidal capacity is found to depend on the size characteristics of the Ag-TiO2 coating. The highest antibacterial activity is obtained for TiO2 nanotubes with opening diameter of about 100 nm and SNs with an average size of 20 nm. MTT assay using osteoblast MG63 cells was performed to examine the cell viability. We suggest that release rate of the silver ions is an important factor controlling the antibacterial activity. Additionally, the size dependency of the bactericidal capacity implies that electrical coupling between silver and TiO2 nanotubes and improved hydrophobicity of the coating might influence the bacterial behavior of the hybrid nanostructures. © 2013 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2017-01-01

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

  9. 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

    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......) fluorescence. OH·-mediated killing by ciprofloxacin was further confirmed by rescue of cells and reduction of HPF fluorescence due to prevention of OH· accumulation by scavenging with thiourea, by chelating with dipyridyl, by decreasing metabolism as well as by anoxic growth. In contrast, no formation of OH...

  10. Production of high specific activity silicon-32

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, D.R. [Los Alamos National Lab., NM (United States); Brzezinski, M.A. [Univ. of California, Santa Barbara, CA (United States). Marine Biotechnology Center

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development Project (LDRD) at Los Alamos National Laboratory (LANL). There were two primary objectives for the work performed under this project. The first was to take advantage of capabilities and facilities at Los Alamos to produce the radionuclide {sup 32}Si in unusually high specific activity. The second was to combine the radioanalytical expertise at Los Alamos with the expertise at the University of California to develop methods for the application of {sup 32}Si in biological oceanographic research related to global climate modeling. The first objective was met by developing targetry for proton spallation production of {sup 32}Si in KCl targets and chemistry for its recovery in very high specific activity. The second objective was met by developing a validated field-useable, radioanalytical technique, based upon gas-flow proportional counting, to measure the dynamics of silicon uptake by naturally occurring diatoms.

  11. Active vibration isolation of high precision machines

    CERN Document Server

    Collette, C; Artoos, K; Hauviller, C

    2010-01-01

    This paper provides a review of active control strategies used to isolate high precisionmachines (e.g. telescopes, particle colliders, interferometers, lithography machines or atomic force microscopes) from external disturbances. The objective of this review is to provide tools to develop the best strategy for a given application. Firstly, the main strategies are presented and compared, using single degree of freedom models. Secondly, the case of huge structures constituted of a large number of elements, like particle colliders or segmented telescopes, is considered.

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

    Science.gov (United States)

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

    1982-04-01

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

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

    Science.gov (United States)

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-07-01

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

  14. High Energy Activation Data Library (HEAD-2009)

    CERN Document Server

    Korovin, Yury A; Konobeyev, Alexander Yu; Stankovskiy, Alexey Yu; Mashnik, Stepan G

    2010-01-01

    A proton activation data library for 682 nuclides from 1-H to 210-Po in the energy range from 150 MeV up to 1 GeV was developed. To calculate proton activation data, the MCNPX 2.6.0 and CASCADE/INPE codes were chosen. Different intranuclear cascade, preequilibrium, and equilibrium nuclear reaction models and their combinations were used. The optimum calculation models have been chosen on the basis of statistical correlations for calculated and experimental proton data taken from the EXFOR library of experimental nuclear data. All the data are written in ENDF-6 format. The library is called HEPAD-2008 (High-Energy Proton Activation Data). A revision of IEAF-2005 neutron activation data library has been performed: A set of nuclides for which the cross-section data can be (and were) updated using more modern and improved models is specified, and the corresponding calculations have been made in the present work. The new version of the library is called IEAF-2009. The HEPAD-2008 and IEAF-2009 are merged to the fin...

  15. 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.

  16. Bactericidal antibody responses elicited by a meningococcal outer membrane vesicle vaccine with overexpressed factor H-binding protein and genetically attenuated endotoxin.

    Science.gov (United States)

    Koeberling, Oliver; Seubert, Anja; Granoff, Dan M

    2008-07-15

    Outer membrane vesicle (OMV) vaccines from mutant Neisseria meningitidis strains engineered to overexpress factor H-binding protein (fHbp) have elicited broadly protective serum antibody responses in mice. The vaccines investigated were not treated with detergents to avoid extracting fHbp, which is a lipoprotein. Because of their high endotoxin content, the vaccines would not be safe to administer to humans. We prepared a native OMV vaccine from a strain engineered to overexpress fHbp and in which the gene encoding LpxL1 was inactivated, which reportedly decreases endotoxin activity. The OMV vaccine from the mutant had a similar or lower ability to induce the expression of proinflammatory cytokines by human peripheral blood mononuclear cells, compared with a detergent-extracted wild-type OMV, and 1000-10,000-fold lower activity than a native wild-type OMV. In mice, the OMV vaccine from the mutant elicited higher serum bactericidal antibody responses to a panel of heterologous N. meningitidis strains than did a control multicomponent recombinant protein vaccine or a detergent-extracted OMV vaccine that has been demonstrated to confer protection against meningococcal disease in humans. The data illustrate the potential to develop a broadly immunogenic native OMV vaccine that has decreased endotoxin activity and is potentially suitable for testing in humans.

  17. Antipneumococcal activity of ceftobiprole, a novel broad-spectrum cephalosporin.

    Science.gov (United States)

    Kosowska, Klaudia; Hoellman, Dianne B; Lin, Gengrong; Clark, Catherine; Credito, Kim; McGhee, Pamela; Dewasse, Bonifacio; Bozdogan, Bülent; Shapiro, Stuart; Appelbaum, Peter C

    2005-05-01

    Ceftobiprole (previously known as BAL9141), an anti-methicillin-resistant Staphylococcus aureus cephalosporin, was very highly active against a panel of 299 drug-susceptible and -resistant pneumococci, with MIC(50) and MIC(90) values (microg/ml) of 0.016 and 0.016 (penicillin susceptible), 0.06 and 0.5 (penicillin intermediate), and 0.5 and 1.0 (penicillin resistant). Ceftobiprole, imipenem, and ertapenem had lower MICs against all pneumococcal strains than amoxicillin, cefepime, ceftriaxone, cefotaxime, cefuroxime, or cefdinir. Macrolide and penicillin G MICs generally varied in parallel, whereas fluoroquinolone MICs did not correlate with penicillin or macrolide susceptibility or resistance. All strains were susceptible to linezolid, quinupristin-dalfopristin, daptomycin, vancomycin, and teicoplanin. Time-kill analyses showed that at 1x and 2x the MIC, ceftobiprole was bactericidal against 10/12 and 11/12 strains, respectively. Levofloxacin, moxifloxacin, vancomycin, and teicoplanin were each bactericidal against 10 to 12 strains at 2x the MIC. Azithromycin and clarithromycin were slowly bactericidal, and telithromycin was bactericidal against only 5/12 strains at 2x the MIC. Linezolid was mainly bacteriostatic, whereas quinupristin-dalfopristin and daptomycin showed marked killing at early time periods. Prolonged serial passage in the presence of subinhibitory concentrations of ceftobiprole failed to yield mutants with high MICs towards this cephalosporin, and single-passage selection showed very low frequencies of spontaneous mutants with breakthrough MICs towards ceftobiprole.

  18. 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.

  19. Null bactericidal effect of ultraviolet radiation emitted by LEDs.

    Directory of Open Access Journals (Sweden)

    Francisco Alcántara Muñoz

    2016-11-01

    Full Text Available This research has aimed to assess the bactericidal effect of ultraviolet light emitted by LEDS on the growth on Petri dishes of microorganisms whose legal limits in foods have been established. An electrically fed apparatus has been designed with precise timing and a camera to prevent light spillage, in which two ultraviolet radiation emission devices were connected by LED technology at different wavelengths: through an array of LEDS emitting at around 350nm, and a single specific emission LED at 280nm. 1000 cfu of E. Coli and S. aureus sown on PCA were used as prototypes of gram negative and positive bacteria, respectively, onto which ultraviolet light was radiated at different time intervals, by means of both devices, with the whole experiment being carried out in triplicate . In none of the three series of treatments at the two wavelengths were reductions in microbial growth observed. The series of sowings on PCA were done on unseeded plates in order to be able to discard the likelihood of subsequent recontamination.

  20. 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.

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

    Science.gov (United States)

    Daniels, G. E.

    1973-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-01

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

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

    Science.gov (United States)

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

    2010-03-01

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

  4. 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

  5. Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

    Science.gov (United States)

    Veerapandian, Murugan; Zhang, Linghe; Krishnamoorthy, Karthikeyan; Yun, Kyusik

    2013-10-01

    A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml-1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml-1 for Bacillus subtilis and 0.5 μg ml-1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside.

  6. Concrete with Highly Active Rice Husk Ash

    Institute of Scientific and Technical Information of China (English)

    FENG Qing-ge; LIN Qing-yu; YU Qi-jun; ZHAO San-ying; YANG Lu-feng; Shuichi Sugita

    2004-01-01

    The overall aim was to investigate the effect of highly active rice husk ash (RHA) produced by an industrial furnace on some properties of concrete. The strength, pore volume and pore distribution of concrete and the Ca(OH)2 content in concrete were investigated by JIS A 1108 (Method of test for compressive strength of concrete), a mercury instrument porosimeter, and the thermogravimetric analysis, respectively. The results show that,with RHA replacement of cement,the compressive strength of concrete is increased evidently;the average pore radius of concrete is greatly decreased, especially the portion of the pores greater than 20nm in radius is decreased while the amount of smaller pores is increased, and the more the RHA replacement, the less the amount of Ca(OH)2 in concrete. The latter two results are the main reasons for the strength enhancement of concrete.

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

    Science.gov (United States)

    Semchenko, Evgeny A.; Day, Christopher J.

    2016-01-01

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

  8. Bactericidal Effect of Pterostilbene Alone and in Combination with Gentamicin against Human Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Wee Xian Lee

    2017-03-01

    Full Text Available The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5 against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.

  9. Bactericidal Effect of Pterostilbene Alone and in Combination with Gentamicin against Human Pathogenic Bacteria.

    Science.gov (United States)

    Lee, Wee Xian; Basri, Dayang Fredalina; Ghazali, Ahmad Rohi

    2017-03-17

    The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5) against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.

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

    Directory of Open Access Journals (Sweden)

    J.-O. Häggblom

    1996-01-01

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

  11. A region of the N-terminal domain of meningococcal factor H-binding protein that elicits bactericidal antibody across antigenic variant groups.

    Science.gov (United States)

    Beernink, Peter T; LoPasso, Carla; Angiolillo, Antonella; Felici, Franco; Granoff, Dan

    2009-05-01

    Meningococcal factor H-binding protein (fHbp) is a promising vaccine antigen. Previous studies described three fHbp antigenic variant groups and identified amino acid residues between 100 and 255 as important targets of variant-specific bactericidal antibodies. We investigated residues affecting expression of an epitope recognized by a murine IgG2a anti-fHbp mAb, designated JAR 4, which cross-reacted with fHbps in variant group 1 or 2 (95% of strains), and elicited human complement-mediated, cooperative bactericidal activity with other non-bactericidal anti-fHbp mAbs with epitopes involving residues between 121 and 216. From filamentous bacteriophage libraries containing random peptides that were recognized by JAR 4, we identified a consensus tripeptide, DHK that matched residues 25-27 in the N-terminal domain of fHbp. Since DHK was present in both JAR 4-reactive and non-reactive fHbps, the tripeptide was necessary but not sufficient for reactivity. Based on site-directed mutagenesis studies, the JAR 4 epitope could either be knocked out of a reactive variant 1 fHbp, or introduced into a non-reactive variant 3 protein. Collectively, the data indicated that the JAR 4 epitope was discontinuous and involved DHK residues beginning at position 25; YGN residues beginning at position 57; and a KDN tripeptide that was present in variant 3 proteins beginning at position 67 that negatively affected expression of the epitope. Thus, the region of fHbp encompassing residues 25-59 in the N-terminal domain is important for eliciting antibodies that can cooperate with other anti-fHbp antibodies for cross-reactive bactericidal activity against strains expressing fHbp from different antigenic variant groups.

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

    Science.gov (United States)

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

    2014-01-01

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

  13. Chicken mannose-binding lectin function in relation to antibacterial activity towards Salmonella enterica

    DEFF Research Database (Denmark)

    Ulrich-Lynge, Sofie Louise; Dalgaard, Tina Sørensen; Norup, Liselotte Rothmann;

    2015-01-01

    ) serotypes B, C1 and D was investigated by flow cytometry, and Staphylococcus aureus (S. aureus) was used for comparison. For S. enterica the C1 serotypes were the only group to exhibit binding to cMBL. Furthermore, functional studies of the role of cMBL in phagocytosis and complement activation were...... performed. Spiking with cMBL had a dose-dependent effect on the HD11 phagocytic activity of S. enterica subsp. enterica serovar Montevideo, and a more pronounced effect in a carbohydrate competitive assay. This cMBL dose dependency of opsonophagocytic activity by HD11 cells was not observed for S. aureus....... No difference in complement-dependent bactericidal activity in serum with high or low cMBL concentrations was found for S. Montevideo. On the other hand, serum with high concentrations of cMBL exhibited a greater bactericidal activity to S. aureus than serum with low concentrations of cMBL. The results...

  14. 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.

  15. [Flow-cytofluorometric study of bactericidal granules in blood phagocytes of animals with various species sensitivity to experimental plague infection].

    Science.gov (United States)

    Kravtsov, A L

    2015-01-01

    Compare the content of bactericidal granules (BG) in blood phagocytes of animals, that differ by species sensitivity to plague infection, under the conditions of measuring, that ensure automatic differentiating by this parameter of monocytes and granulocytes of human blood. Human whole blood leukocytes were studied, as well as from 7 animal species: mice, guinea pigs, golden hamsters, white rats, rabbits, dogs and horses. Acridine orange (AO) was used for supra-vital staining in primary (bactericidal) granule cells. Relative BG content was measured in separate cells in conventional units of red fluorescence intensity by flow cytofluorometry. Deficiency of AO molecules in BG, that correlates with deficiency of leukocyte elastase in cells, that is most pronounced in mice and lest pronounced in rabbits, was established to be characteristic for all the blood phagocytes of all the laboratory animal species sensitive to plague. Blood phagocytes of dogs and horses, that were non-sensitive to plague, differed by high heterogeneity by the studied parameter, and in horse blood innate immunity cells were detected, that contained 2.5 times higher amount of BG, than blood granulocytes of humans. Leukocyte BG, that have enzyme cationic proteins: elastase, cathepsin G, protease 3 and myeloperoxidase, play and important role in protection of organism from plague infection.

  16. 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.

  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. Development of Antifouling and Bactericidal Coatings for Platelet Storage Bags Using Dopamine Chemistry.

    Science.gov (United States)

    Hadjesfandiari, Narges; Weinhart, Marie; Kizhakkedathu, Jayachandran N; Haag, Rainer; Brooks, Donald E

    2017-09-29

    Platelets have a limited shelf life, due to the risk of bacterial contamination and platelet quality loss. Most platelet storage bags are made of a mixture of polyvinyl chloride with a plasticizer, denoted as pPVC. To improve biocompatibility of pPVC with platelets and to inhibit bacterial biofilm formation, an antifouling polymer coating is developed using mussel-inspired chemistry. A copolymer of N,N-dimethylacrylamide and N-(3-aminopropyl)methacrylamide hydrochloride is synthesized and coupled with catechol groups, named DA51-cat. Under mild aqueous conditions, pPVC is first equilibrated with an anchoring polydopamine layer, followed by a DA51-cat layer. Measurements show this coating decreases fibrinogen adsorption to 5% of the control surfaces. One-step coating with DA51-cat does not coat pPVC efficiently although it is sufficient for coating silicon wafers and gold substrates. The dual layer coating on platelet bags resists bacterial biofilm formation and considerably decreases platelet adhesion. A cationic antimicrobial peptide, E6, is conjugated to DA51-cat then coated on silicon wafers and introduces bactericidal activity to these surfaces. Time-of-flight second ion-mass spectroscopy is successfully applied to characterize these surfaces. pPVC is widely used in medical devices; this method provides an approach to controlling biofouling and bacterial growth on it without elaborate surface modification procedures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    Abramov, Y; Aronovitch, J; Ramu, A

    1996-01-01

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

  20. 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.

  1. High-Throughput Analysis of Enzyme Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Guoxin [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    High-throughput screening (HTS) techniques have been applied to many research fields nowadays. Robot microarray printing technique and automation microtiter handling technique allows HTS performing in both heterogeneous and homogeneous formats, with minimal sample required for each assay element. In this dissertation, new HTS techniques for enzyme activity analysis were developed. First, patterns of immobilized enzyme on nylon screen were detected by multiplexed capillary system. The imaging resolution is limited by the outer diameter of the capillaries. In order to get finer images, capillaries with smaller outer diameters can be used to form the imaging probe. Application of capillary electrophoresis allows separation of the product from the substrate in the reaction mixture, so that the product doesn't have to have different optical properties with the substrate. UV absorption detection allows almost universal detection for organic molecules. Thus, no modifications of either the substrate or the product molecules are necessary. This technique has the potential to be used in screening of local distribution variations of specific bio-molecules in a tissue or in screening of multiple immobilized catalysts. Another high-throughput screening technique is developed by directly monitoring the light intensity of the immobilized-catalyst surface using a scientific charge-coupled device (CCD). Briefly, the surface of enzyme microarray is focused onto a scientific CCD using an objective lens. By carefully choosing the detection wavelength, generation of product on an enzyme spot can be seen by the CCD. Analyzing the light intensity change over time on an enzyme spot can give information of reaction rate. The same microarray can be used for many times. Thus, high-throughput kinetic studies of hundreds of catalytic reactions are made possible. At last, we studied the fluorescence emission spectra of ADP and obtained the detection limits for ADP under three different

  2. Metabolic Activity of Bacteria at High Pressure

    Science.gov (United States)

    Picard, A.; Daniel, I.; Oger, P.

    2008-12-01

    Over the last 20 years, there has been increasing evidence for the presence of a large number of microbes in the oceanic subsurface. Such a habitat has a very low energy input because it is deprived of light. A few meters below the sediment surface, conditions are already anoxic in most cases, sulfate reduction and/or methanogenesis becoming thus the primary respiratory reactions of organic matter. Neither the fate of methanogenesis, nor the fate of Dissimilatory Metal-Reduction (DMR) has been investigated so far as a function of pressure. For this reason, we measured experimentally the pressure limits of microbial anaerobic energetic metabolism. In practice, we measured in situ the kinetics of selenite respiration by the bacterial model Shewanella oneidensis MR-1 under high hydrostatic pressure (HHP) between 0 and 150 MPa at 30°C. MR-1 stationary-phase cells were used in Luria-Bertani (LB) medium amended with lactate as an additional electron donor and sodium selenite as an electron acceptor. In situ measurements were performed by X- ray Absorption Near-Edge Structure (XANES) spectroscopy in both a diamond-anvil cell and an autoclave. A red precipitate of amorphous Se(0) was virtually observed at any pressure to 150 MPa. A progressive reduction of selenite Se(IV) into selenium Se(0) was also observed in the evolution of XANES spectra with time. All kinetics between 0.1 and 150 MPa can be adjusted to a first order kinetic law. MR-1 respires all available selenite up to 60 MPa. Above 60 MPa, the respiration yield decreases linearly as a function of pressure and reaches 0 at 155 ±5 MPa. This indicates that selenite respiration by Shewanella oneidensis MR-1 stops at about 155 MPa, whereas its growth is arrested at 50 MPa. Hence, the present results show that the respiration of selenium by the strain MR-1 occurs efficiently up to 60 MPa and 30°C, i.e. from the surface of a continental sediment to an equivalent depth of about 2 km, or beneath a 5-km water column and

  3. 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

  4. 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.

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

    Science.gov (United States)

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

    2014-08-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

  7. 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.

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

    Science.gov (United States)

    Odell, E W; Segal, A W

    1988-10-07

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

  9. Bactericidal pathway of Escherichia coli in buffered saline treated with oxygen radicals

    Science.gov (United States)

    Kobayashi, Tsuyoshi; Iwata, Natsumi; Oh, Jun-Seok; Hahizume, Hiroshi; Ohta, Takayuki; Takeda, Keigo; Ishikawa, Kenji; Hori, Masaru; Ito, Masafumi

    2017-04-01

    Bactericidal effects of phosphate buffered saline treated with electrically neutral oxygen radicals on Escherichia coli (E. coli) are studied using an atmospheric pressure radical source and colony counting method. To clarify the bactericidal mechanism, the chemistry in phosphate buffers treated with oxygen radicals with and without saline has been quantitatively investigated using the well-established chemical reporters N,N-diethyl-p-phenylenediamine reagent and Amplex Red for residual chlorine (HClO and ClO-) and hydrogen peroxide (H2O2), respectively. From the results, we have found that the presence of chlorine in the solutions treated with oxygen radicals is the most important factor in the further chemical reactions to generate hypochlorous acid in E. coli death, and H2O2 is also linked to the bactericidal effect via an indirect chemical pathway.

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

    Directory of Open Access Journals (Sweden)

    Lei Lei

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

  11. α-Helical domain is essential for antimicrobial activity of high mobility group nucleosomal binding domain 2 (HMGN2)

    Institute of Scientific and Technical Information of China (English)

    Yun FENG; Ning HUANG; Qi WU; Lang BAO; Bo-yao WANG

    2005-01-01

    Aim: To examine the antimicrobial spectrum and functional structure of high mobility group nucleosomal binding domain 2 (HMGN2). Methods: OMIGA protein structure software was used to analyze the two-dimensional structure of HMGN2. Synthetic short peptides were generated for studying the relationship between function and structure. Prokaryotic expression vectors were constructed for the holo-HMGN2 and its helical domain. Their E coli-based products were also prepared for antimicrobial testing. The antimicrobial assay included minimal effective concentration, minimal inhibitory concentration, and minimal bactericidal concentration. Results: OMIGA protein structure software analysis revealed a transmembrane α-helical structure (the putative antimicrobial domain) located from position 18 to 48 of the HMGN2 protein sequence. The antimicrobial assay showed that the MIC of the recombinant holo-HMGN2 against E coli ML-35p (an ampicillin-resistance strain), Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 10231 were 12.5, 25, and 100 mg/L, respectively. Against the same microorganisms, the MIC of the synthetic HMGN2 α-helical domain were 12.5, 25,and 100 mg/L, respectively, that is, the same as with the recombinant form of HMGN2. In contrast, recombinant holo-HMGN2 was inactive against Staphylococcus aureus ATCC 25923. The synthetic N-terminal and C-terminal fragments of HMGN2 had no antimicrobial activity against E coli ML-35p, P aeruginosa ATCC 27853 or C albicans ATCC 10231. Conclusion: HMGN2 showed potent antimicrobial activity against E coli ML-35p, P aeruginosa ATCC 27853 and, to some extent, against C albicans ATCC 10231, but was inactive against S aureus ATCC 25923 in these assay systems. Its α-helical structure may be essential for the antimicrobial activity of HMGN2.

  12. Highly active thermally stable nanoporous gold catalyst

    Science.gov (United States)

    Biener, Juergen; Wittstock, Arne; Biener, Monika M.; Bagge-Hansen, Michael; Baeumer, Marcus; Wichmann, Andre; Neuman, Bjoern

    2016-12-20

    In one embodiment, a system includes a nanoporous gold structure and a plurality of oxide particles deposited on the nanoporous gold structure; the oxide particles are characterized by a crystalline phase. In another embodiment, a method includes depositing oxide nanoparticles on a nanoporous gold support to form an active structure and functionalizing the deposited oxide nanoparticles.

  13. Highly active thermally stable nanoporous gold catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Biener, Juergen; Wittstock, Arne; Biener, Monika M.; Bagge-Hansen, Michael; Baeumer, Marcus; Wichmann, Andre; Neuman, Bjoern

    2016-12-20

    In one embodiment, a system includes a nanoporous gold structure and a plurality of oxide particles deposited on the nanoporous gold structure; the oxide particles are characterized by a crystalline phase. In another embodiment, a method includes depositing oxide nanoparticles on a nanoporous gold support to form an active structure and functionalizing the deposited oxide nanoparticles.

  14. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  17. DEVELOPMENT OF INDUSTRIAL TECHNOLOGY BACTERICIDAL PATCH OF THICK OAK BARK EXTRACT

    Directory of Open Access Journals (Sweden)

    N. V. Hohlenkova

    2013-06-01

    Full Text Available Theoretically and experimentally efficient technology of bactericidal patch of thick oak bark extract in LLC "ВUС Sarepta-mediplast" have been substantiated. According to the research critical parameters of production were identified, established their permissible deviations.

  18. 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. © 2012 American Chemical Society

  19. Bactericidal Efficiency of Silver Nanoparticles Synthesized from Annona squamosa

    Science.gov (United States)

    Jayavardhanan, R.; Nanda, Anima

    2016-09-01

    Nanotechnology is described as an emerging technology that not only holds promise for society, but also is capable of providing novel approaches to overcome our common problems. The present study focused on the synthesis of silver nanoparticles using the metabolites of Annona squamosa seeds. The biological reduction procedure proposed in this method was considered as better one compared to chemical mediated reduction methods. The advantages include nontoxic to the environment, less energy consuming and highly suitable for further biological applications. The seeds were separated from the fruit pulp, grinded into powder and dissolved in distilled water. The suspension was used as reducing agent and treated with silver nitrate at the concentration of 1mM. The reduction reaction was continuously monitored by UV-visible photo spectrometer. Further the samples were subjected to AFM, SEM and XRD analysis for the confirmation of their size, structure, agglomerations and the arrangements of crystals. Finally the antibacterial properties of nanoparticles were tested against clinically important pathogenic microorganisms using disc diffusion method and compared with the activities of standard antibiotics. The combinational effects of nanoparticles with commercial antibiotics also were tested by the same method.

  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. Antimicrobial activity of human hepcidin 20 and 25 against clinically relevant bacterial strains: effect of copper and acidic pH.

    Science.gov (United States)

    Maisetta, Giuseppantonio; Petruzzelli, Raffaele; Brancatisano, Franca Lisa; Esin, Semih; Vitali, Alberto; Campa, Mario; Batoni, Giovanna

    2010-11-01

    Hepcidin 25 (hep-25) is a peptide primarily produced by human liver with a central role in iron homeostasis. Its isoform, hepcidin 20 (hep-20), has an unknown function and lacks the first five aminoacids of the amino-terminal portion. This sequence is crucial for iron regulation by hep-25 and contains a molecular motif able to bind metals. Aim of this study, was to evaluate the antibacterial properties of both peptides in vitro, against a wide range of bacterial clinical isolates and in different experimental conditions. Although both peptides were found to be bactericidal against a variety of clinical isolates with different antibiotic resistance profiles, hep-20 was active at lower concentrations than hep-25, in most of the cases. Killing kinetics, carried on in sodium-phosphate buffer at pH 7.4, demonstrated that bactericidal activity occurred not earlier than 30-90 min of incubation. Bactericidal activity of hep-25 was slightly enhanced in the presence of copper, while the same metal did not affect the activity of hep-20. Interestingly, bactericidal activity of both hepcidins was highly enhanced at acidic pH. Acidic pH (pH 5.0 and 6.6) not only reduced the microbicidal concentrations of hepcidins, but also shortened the killing times of both peptides, as compared to pH 7.4. Combining hep-20 and hep-25 at pH 5.0 a bactericidal effect could be obtained at very low concentrations of both peptides. These results render hepcidins interesting for the design of new drugs for the treatment of infections occurring in body districts with physiologic acidic pH. Copyright © 2010 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    G. Caccianiga

    2008-04-01

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

  3. Active control system for high speed windmills

    Science.gov (United States)

    Avery, D.E.

    1988-01-12

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

  4. A Novel Small-Molecule Inhibitor of the Mycobacterium tuberculosis Demethylmenaquinone Methyltransferase MenG Is Bactericidal to Both Growing and Nutritionally Deprived Persister Cells

    Science.gov (United States)

    Sukheja, Paridhi; Kumar, Pradeep; Mittal, Nisha; Li, Shao-Gang; Singleton, Eric; Russo, Riccardo; Perryman, Alexander L.; Shrestha, Riju; Awasthi, Divya; Husain, Seema; Soteropoulos, Patricia; Brukh, Roman; Connell, Nancy; Freundlich, Joel S.

    2017-01-01

    ABSTRACT Active tuberculosis (TB) and latent Mycobacterium tuberculosis infection both require lengthy treatments to achieve durable cures. This problem has partly been attributable to the existence of nonreplicating M. tuberculosis “persisters” that are difficult to kill using conventional anti-TB treatments. Compounds that target the respiratory pathway have the potential to kill both replicating and persistent M. tuberculosis and shorten TB treatment, as this pathway is essential in both metabolic states. We developed a novel respiratory pathway-specific whole-cell screen to identify new respiration inhibitors. This screen identified the biphenyl amide GSK1733953A (DG70) as a likely respiration inhibitor. DG70 inhibited both clinical drug-susceptible and drug-resistant M. tuberculosis strains. Whole-genome sequencing of DG70-resistant colonies identified mutations in menG (rv0558), which is responsible for the final step in menaquinone biosynthesis and required for respiration. Overexpression of menG from wild-type and DG70-resistant isolates increased the DG70 MIC by 4× and 8× to 30×, respectively. Radiolabeling and high-resolution mass spectrometry studies confirmed that DG70 inhibited the final step in menaquinone biosynthesis. DG70 also inhibited oxygen utilization and ATP biosynthesis, which was reversed by external menaquinone supplementation. DG70 was bactericidal in actively replicating cultures and in a nutritionally deprived persistence model. DG70 was synergistic with the first-line TB drugs isoniazid, rifampin, and the respiratory inhibitor bedaquiline. The combination of DG70 and isoniazid completely sterilized cultures in the persistence model by day 10. These results suggest that MenG is a good therapeutic target and that compounds targeting MenG along with standard TB therapy have the potential to shorten TB treatment duration. PMID:28196957

  5. Antibacterial activity against Ralstonia solanacearum of phenolic constituents isolated from dragon's blood.

    Science.gov (United States)

    Wang, Hui; Luo, Ying; Dai, Haofu; Mei, Wenli

    2013-03-01

    Ralstonia solanacearum is a worldwide and devastating plant pathogen infesting over 200 host species. Synthetic bactericides against the pathogen have only achieved limited success and always cause both crop contamination and environmental pollution. However, natural bactericides are effective for protecting cultivated crops from destruction by disease, without the adverse effects of chemical bactericides. In this paper, fifteen phenolic constituents from dragon's blood were screened for their antimicrobial activity against Ralstonia solanacearum, and all exhibited inhibitory activity. These compounds are potential leading compounds for the development of bactericides against wilt diseases caused by Ralstonia solanacearum.

  6. Ceftobiprole: in-vivo profile of a bactericidal cephalosporin.

    Science.gov (United States)

    Chambers, H F

    2006-04-01

    Resistance to antimicrobials is a significant and growing problem, limiting treatment options, especially for serious Gram-positive infections. Ceftobiprole is a novel broad-spectrum cephalosporin that is active in vitro against streptococci and staphylococci, including penicillin-resistant strains of pneumococci and methicillin-resistant Staphylococcus aureus (MRSA). It maintains the activity of extended-spectrum cephalosporins against Gram-negative bacteria, including Enterobacteriaceae. The in-vivo activity of ceftobiprole has been demonstrated in mouse sepsis and subcutaneous abscess models of infection. Its activity also has been examined in several discriminative models of infection that mimic specific diseases in humans and permit testing of antimicrobial activity under a variety of defined pharmacokinetic conditions. These include experimental pneumonia in mice, a tissue cage model of foreign body infection in rats, and endocarditis models in rats and rabbits. In these models, ceftobiprole exhibits activity equivalent or superior to that of comparators against MRSA, including vancomycin-intermediate strains. These models also confirm the in-vivo activity of ceftobiprole against Gram-negative bacteria that are susceptible in vitro. The results from animal models support the evaluation of the clinical efficacy of ceftobiprole in humans and also predict clinical efficacy in the empirical treatment of severe infections. The broad spectrum of activity may allow ceftobiprole to be used as monotherapy for serious hospital-acquired infections where combination therapy would otherwise be required.

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

    Science.gov (United States)

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

    2004-07-01

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

  8. Antileishmanial, Antimicrobial and Antifungal Activities of Some New Aryl Azomethines

    Directory of Open Access Journals (Sweden)

    Masoom Yasinzai

    2010-01-01

    Full Text Available A series of eighteen azomethines has been synthesized by the reaction of appropriate primary aromatic amines with aryl and/or heteroaryl carboxaldehydes. The synthesized azomethines have been evaluated for their in vitro antileishmanial, antibacterial and antifungal activities. The results revealed some antifungal activity of most of the synthesized compounds, whereas the antileishmaniasis activity results highlighted that all synthesized azomethines inhibited parasite growth and most of them showed highly potent action towards Leishmania major promastigotes. No remarkable bactericidal activities were observed.

  9. High protein binding and cidal activity against penicillin-resistant S. pneumoniae: a cefditoren in vitro pharmacodynamic simulation.

    Directory of Open Access Journals (Sweden)

    David Sevillano

    Full Text Available BACKGROUND: Although protein binding is a reversible phenomenon, it is assumed that antibacterial activity is exclusively exerted by the free (unbound fraction of antibiotics. METHODOLOGY/PRINCIPAL FINDINGS: Activity of cefditoren, a highly protein bound 3(rd generation cephalosporin, over 24h after an oral 400 mg cefditoren-pivoxil bid regimen was studied against six S. pneumoniae strains (penicillin/cefditoren MICs; microg/ml: S1 (0.12/0.25, S2 (0.25/0.25, S3 and S4 (0.5/0.5, S5 (1/0.5 and S6 (4/0.5. A computerized pharmacodynamic simulation with media consisting in 75% human serum and 25% broth (mean albumin concentrations = 4.85+/-0.12 g/dL was performed. Protein binding was measured. The cumulative percentage of a 24h-period that drug concentrations exceeded the MIC for total (T > MIC and unbound concentrations (fT > MIC, expressed as percentage of the dosing interval, were determined. Protein binding was 87.1%. Bactericidal activity (> or = 99.9% initial inocula reduction was obtained against strains S1 and S2 at 24h (T > MIC = 77.6%, fT > MIC = 23.7%. With T > MIC of 61.6% (fT > MIC = 1.7%, reductions against S3 and S4 ranged from 90% to 97% at 12h and 24h; against S5, reduction was 45.1% at 12h and up to 85.0% at 24h; and against S6, reduction was 91.8% at 12h, but due to regrowth of 52.9% at 24h. Cefditoren physiological concentrations exerted antibacterial activity against strains exhibiting MICs of 0.25 and 0.5 microg/ml under protein binding conditions similar to those in humans. CONCLUSIONS/SIGNIFICANCE: The results of this study suggest that, from the pharmacodynamic perspective, the presence of physiological albumin concentrations may not preclude antipneumococcal activity of highly bound cephalosporins as cefditoren.

  10. Seroprevalence of Antibody-Mediated, Complement-Dependent Opsonophagocytic Activity against Neisseria meningitidis Serogroup B in England.

    Science.gov (United States)

    Humphries, Holly E; Brookes, Charlotte; Allen, Lauren; Kuisma, Eeva; Gorringe, Andrew; Taylor, Stephen

    2015-05-01

    The correlate of protection for the licensure of meningococcal vaccines is serum bactericidal activity. However, evidence indicates that a complex situation and other mechanisms, such as antibody-mediated, complement-dependent opsonophagocytosis (OP), may play a role in protection and should be investigated in order to understand immunity to this disease. In this study, a high-throughput flow cytometric opsonophagocytic assay (OPA) was optimized. The assay measures the presence of killed fluorescently labeled Neisseria meningitidis within human granulocytes (differentiated HL60 cells) by flow cytometry, using IgG-depleted pooled human plasma as an exogenous source of complement. This method was found to be reliable and correlated with the results of an opsonophagocytic killing assay. The OPA was used to measure OP activity in 1,878 serum samples from individuals ranging from 0 to 99 years of age against N. meningitidis strain NZ98/254 (B:4:P1.7-2,4). The levels of OP activity in individual serum samples varied greatly. OP activity showed an initial peak in the 6- to 12-month age group corresponding to a peak in disease incidence. The OP activity dropped in childhood until the late teenage years, although there was still a higher percentage of individuals with OP activity than with protective bactericidal antibody titers. OP activity reached a peak in the 30- to 39-year age group and then declined. This later peak in OP activity did not coincide with the young adults in whom peak serum bactericidal activity and disease incidence occurred. The demonstration of OP activity when disease incidence is low and when protective bactericidal antibody titers are not detected may indicate a role for OP in protection from meningococcal disease in these age groups.

  11. Ungeremine and Its hemisynthesized analogues as bactericides against Flavobacterium columnare.

    Science.gov (United States)

    Schrader, Kevin K; Avolio, Fabiana; Andolfi, Anna; Cimmino, Alessio; Evidente, Antonio

    2013-02-13

    The Gram-negative bacterium Flavobacterium columnare is the cause of columnaris disease, which can occur in channel catfish ( Ictalurus punctatus ). In a previous study, the betaine-type alkaloid ungeremine, 1, obtained from Pancratium maritimum L. was found to have strong antibacterial activity against F. columnare. In this study, analogues of 1 were evaluated using a rapid bioassay for activity against F. columnare to determine if the analogues might provide greater antibacterial activity and to determine structure-activity relationships of the test compounds. Several ungeremine analogues were prepared by hydrochlorination of the alkaloid and by selenium dioxide oxidation of both lycorine, 7, and pseudolycorine, 8, which yielded the isomer of ungeremine, 3, and zefbetaine, 4, respectively. The treatment of lycorine with phosphorus oxychloride allowed the synthesis of an anhydrolycorine lactam, 5, showing, with respect to 1, the deoxygenation and oxygenation of C-2 and C-7 of the C and B rings, respectively. The results of the structure-activity relationship studies showed that the aromatization of the C ring and the oxidation to an azomethine group of C-7 of the B ring are structural features important for antibacterial activity. In addition, the position of the oxygenation of the C ring as well as the presence of the 1,3-dioxole ring joined to the A ring of the pyrrolo[de]phenanthridine skeleton also plays a significant role in imparting antibacterial activity. On the basis of 24-h 50% inhibition concentration (IC(50)) results, ungeremine hydrochloride, 2, was similar in toxicity to 1, whereas 5 had the lowest activity. Analogue 2 is soluble in water, which may provide the benefit for use as an effective feed additive or therapeutant compared to ungeremine.

  12. Catalytically highly active top gold atom on palladium nanocluster.

    Science.gov (United States)

    Zhang, Haijun; Watanabe, Tatsuya; Okumura, Mitsutaka; Haruta, Masatake; Toshima, Naoki

    2011-10-23

    Catalysis using gold is emerging as an important field of research in connection with 'green' chemistry. Several hypotheses have been presented to explain the markedly high activities of Au catalysts. So far, the origin of the catalytic activities of supported Au catalysts can be assigned to the perimeter interfaces between Au nanoclusters and the support. However, the genesis of the catalytic activities of colloidal Au-based bimetallic nanoclusters is unclear. Moreover, it is still a challenge to synthesize Au-based colloidal catalysts with high activity. Here we now present the 'crown-jewel' concept (Supplementary Fig. S1) for preparation of catalytically highly Au-based colloidal catalysts. Au-Pd colloidal catalysts containing an abundance of top (vertex or corner) Au atoms were synthesized according to the strategy on a large scale. Our results indicate that the genesis of the high activity of the catalysts could be ascribed to the presence of negatively charged top Au atoms.

  13. Identification of highly active flocculant proteins in bovine blood.

    Science.gov (United States)

    Piazza, George J; Nuñez, Alberto; Garcia, Rafael A

    2012-03-01

    Synthetic polymeric flocculants are used extensively for wastewater remediation, soil stabilization, and reduction in water leakage from unlined canals. Sources of highly active, inexpensive, renewable flocculants are needed to replace synthetic flocculants. High kaolin flocculant activity was documented for bovine blood (BB) and blood plasma with several anticoagulant treatments. BB serum also had high flocculant activity. To address the hypothesis that some blood proteins have strong flocculating activity, the BB proteins were separated by SEC. Then, the major proteins of the flocculant-active fractions were separated by SDS-PAGE. Identity of the major protein components was determined by tryptic digestion and peptide analysis by MALDI TOF MS. The sequence of selected peptides was confirmed using TOF/TOF-MS/MS fragmentation. Hemoglobin dimer (subunits α and β) was identified as the major protein component of the active fraction in BB; its high flocculation activity was confirmed by testing a commercial sample of hemoglobin. In the same manner, three proteins from blood plasma (fibrinogen, γ-globulin, α-2-macroglobulin) were found to be highly active flocculants, but bovine serum albumin, α-globulin, and β-globulin were not flocculants. On a mass basis, hemoglobin, γ-globulin, α-2-macroglobulin were as effective as anionic polyacrylamide (PAM), a widely used synthetic flocculant. The blood proteins acted faster than PAM, and unlike PAM, the blood proteins flocculants did not require calcium salts for their activity.

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

    Science.gov (United States)

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

    2015-10-01

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

  15. Social capital and physical activity among Croatian high school students.

    Science.gov (United States)

    Novak, D; Doubova, S V; Kawachi, I

    2016-06-01

    To examine factors associated with regular physical activity in Croatian adolescents. A cross-sectional survey among high school students was carried out in the 2013/14 school year. A survey was conducted among 33 high schools in Zagreb City, Croatia. Participants were students aged 17-18 years. The dependent variables were regular moderate to vigorous physical activity (MVPA) and overall physical activity measured by the short version of International Physical Activity Questionnaire and defined as 60 min or more of daily physical activity. The independent variables included family, neighborhood, and high school social capital. Other study covariates included: socio-economic status, self-rated health, psychological distress and nutritional status. The associations between physical activity and social capital variables were assessed separately for boys and girls through multiple logistic regression and inverse probability weighting in order to correct for missing data bias. A total of 1689 boys and 1739 girls responded to the survey. A higher percentage of boys reported performing regular vigorous and moderate physical activity (59.4%) and overall physical activity (83.4%), comparing with the girls (35.4% and 70%, respectively). For boys, high family social capital and high informal social control were associated with increased odds of regular MVPA (1.49, 95%CI: 1.18 - 1.90 and 1.26, 95%CI: 1.02 - 1.56, respectively), compared to those with low social capital. For girls, high informal social control was associated with regular overall physical activity (OR 1.38, 95% CI: 1.09 - 1.76). High social capital is associated with regular MVPA in boys and regular overall activity in girls. Intervention and policies that leverage community social capital might serve as an avenue for promotion of physical activity in youth. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  16. 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.

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

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

    2013-10-01

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

  19. Ungeremine and its hemisynthetic analogues as bactericides against Flavobacterium columnare

    Science.gov (United States)

    The Gram-negative bacterium Flavobacterium columunare is the cause of colmunaris disease in channel catfish (Ictalurus punctatus). In a previous study, the betaine-type alkaloid ungeremine, 1 obtained from Pancratium maritimum L. was found to have strong antibacterial activity against F. columnare. ...

  20. Synthesis, Characterizations of Superparamagnetic Fe3O4-Ag Hybrid Nanoparticles and Their Application for Highly Effective Bacteria Inactivation

    DEFF Research Database (Denmark)

    Tung, L.M.; Cong, N.X.; Huy, L.T.

    2016-01-01

    In recent years, outbreaks of infectious diseases caused by pathogenic micro-organisms pose a serious threat to public health. In this work, Fe3O4-Ag hybrid nanoparticles were synthesized by simple chemistry method and these prepared nanoparticles were used to investigate their antibacterial...... properties and mechanism against methicilline-resistant Staphylococcus aureus (MRSA) pathogen. The formation of dimer-like nanostructure of Fe3O4-Ag hybrid NPs was confirmed by X-ray diffraction and High-resolution Transmission Electron Microscopy. Our biological analysis revealed that the Fe3O4-Ag hybrid...... NPs showed more noticeable bactericidal activity than that of plain Fe3O4 NPs and Ag-NPs. We suggest that the enhancement in bactericidal activity of Fe3O4-Ag hybrid NPs might be likely from main factors such as: (i) enhanced surface area property of hybrid nanoparticles; (ii) the high catalytic...

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

    Science.gov (United States)

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

    2010-07-01

    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. Tempe extract showed a high antibacterial activity against B. cereus ATCC 14579 based on optical density and viable count measurements. This growth inhibition was manifested by a 4 log CFU ml(-1) reduction, within the first 15 min of exposure. Tempe extracts also rapidly inactivated B. cereus spores upon germination. Viability and membrane permeability assessments using fluorescence probes showed rapid inactivation and permeabilization of the cytoplasmic membrane confirming the bactericidal mode of action. Cooked beans and Rhizopus grown on different media did not show antibacterial activity, indicating the unique association of the antibacterial activity with tempe. Subsequent characterization of the antibacterial activity revealed that heat treatment and protease addition nullified the bactericidal effect, indicating the proteinaceous nature of the bioactive compound. During fermentation of soya beans with Rhizopus, compounds are released with extensive antibacterial activity against B. cereus cells and spores. The results show the potential of producing natural antibacterial compounds that could be used as ingredients in food preservation and pathogen control. © 2009 The Authors. Journal compilation © 2009 The Society for Applied Microbiology.

  2. In vitro activity of a polyhexanide-betaine solution against high-risk clones of multidrug-resistant nosocomial pathogens.

    Science.gov (United States)

    López-Rojas, Rafael; Fernández-Cuenca, Felipe; Serrano-Rocha, Lara; Pascual, Álvaro

    2017-01-01

    To determine the in vitro activity of a polyhexanide-betaine solution against collection strains and multidrug-resistant (MDR) nosocomial isolates, including high-risk clones. We studied of 8 ATCC and 21 MDR clinical strains of Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, including the multiresistant high-risk clones. The MICs and MBCs of a 0.1% polyhexanide-0.1% betaine solution were determined by microdilution. For each species, strains with the highest MICs were selected for further experiments. The dilution-neutralization test (PrEN 12054) was performed by incubating bacterial inocula of 10(6)CFU/mL for 1min with undiluted 0.1% polyhexanide-betaine solution. The CFUs were counted after neutralization. Growth curves and time-kill curves at concentrations of 0.25, 1, 4, and 8×MIC, were performed. MICs of recovered strains were determined when regrowth was observed in time-kill studies after 24h of incubation. Strains with reduced susceptibility were selected by serial passage on plates with increasing concentrations of polyhexanide-betaine, and MICs were determined. Polyhexanide-betaine MIC range was 0.5-8mg/L. MBCs equalled or were 1 dilution higher than MICs. The dilution-neutralization method showed total inoculum clearance of all strains. In time-kill curves, no regrowth was observed at 4×MIC, except for S. aureus (8×MIC). Increased MICs were not observed in time-kill curves, or after serial passages after exposure to polyhexanide-betaine. Polyhexanide-betaine presented bactericidal activity against all MDR clinical isolates tested, including high-risk clones, at significantly lower concentrations and time of activity than those commercially used. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  3. 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.

  4. 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.

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

    Science.gov (United States)

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

    2009-12-01

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

  6. 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.

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

    Science.gov (United States)

    2002-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-15

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

  10. Inhibitory and bactericidal power of mangosteen rind extract towards Porphyromonas Gingivalis and Actinobacillus Actinomycetemcomitans (Laboratory test

    Directory of Open Access Journals (Sweden)

    Ina Hendiani

    2017-08-01

    Full Text Available Introduction: The bacteria that cause the occurrence of pathogens of periodontal disease are gram negative anaerobes. These bacteria include Pophyromonas Gingivalis and Actinobacillus Actinomycetemcomitans. Mangosteen skin extract is known to have anti-inflammatory, anti microbial, and anti oxidant properties. The extract of the mangosteen peel is altered in gel preparation in order to streamline its clinical application in periodontal disease. The purpose of this study was to examine the antibacterial power of the ginger mangosteen tree extract gel against Pophyromonas gingivalis and Actinobacillus Actinomycetemcomitans (Aggregatibacter Actinomycetemcomitans. Methods: This research was conducted by experimental laboratory. Mangosteen fruit extract gel with concentration of 100%, 50%, 25%, 12,5%, 6,25%, 3,125% and 0,78% were tested against Pophyromonas Gingivalis and Aggregatibacter Actinomycetemcomitans with agar diffusion method. Results and Discussion: The results of this study indicate that for Actinobacilus Aggregatibacter bacteria minimal inhibitory concentration at a concentration of 6.25% with a diameter of 13,5mm inhibition. Minimal bactericidal concentration at 12,5% concentration with 14,7mm inhibitory diameter. In the test of Pophyromonas Gingivalis bacteria, minimal inhibitory concentrations were obtained at a concentration of 1.56% and a minimum bactericidal concentration was obtained at a concentration of 3.125%. Conclusion: The conclusion that mangosteen peel skin gel extract can inhibit bacterial growth and is bactericidal against Pophyromonas Gingivalis and Actinobacillus Actinomycetemcomitans (Aggregatibacter Actinomycetecomitans.

  11. Effects of CO2 on the resuscitation of Listeria monocytogenes injured by various bactericidal treatments.

    Science.gov (United States)

    Van Houteghem, Nancy; Devlieghere, Frank; Rajkovic, Andreja; Gómez, Sandra Maria Osés; Uyttendaele, Mieke; Debevere, Johan

    2008-03-31

    To assure the microbiological safety and quality of a food product, a combination of preservation hurdles is often used. Therefore, the effects of carbon dioxide at concentrations of 0, 20, 40 and 60% in modified atmospheres on the resuscitation of Listeria monocytogenes cells injured by mild bactericidal treatments during storage at 7 degrees C were examined. The bactericidal treatments were intense light pulses (ILP), chlorine dioxide (ClO(2)), lactic acid (LA) and heat. The results indicated additional bactericidal effects of CO(2) on cultures treated with LA, ClO(2) and ILP, with additional reductions in viable L. monocytogenes of 0.5-1.0 log cfu/ml. Lag phase duration was significantly different between the different treatments, with non-treated cells having the shortest lag phase, followed by that of heat, intense light pulses, lactic acid and finally ClO(2) treated cells. Maximum growth rate was also estimated and results showed a negative correlation with increasing CO(2) concentrations. A relationship was found between the amount of sub-lethally damaged cells after a mild inactivation treatment and the lag phase duration in the CO(2) environment. Current findings demonstrate the possibility that combining mild decontamination treatments and packaging in a CO(2) enriched environment could reduce the risk of L. monocytogenes infections in food due to an extension of the lag phase.

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

    Science.gov (United States)

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

    2015-02-17

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

  13. 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.

  14. Nanoparticles as Efflux Pump and Biofilm Inhibitor to Rejuvenate Bactericidal Effect of Conventional Antibiotics

    Science.gov (United States)

    Gupta, Divya; Singh, Ajeet; Khan, Asad U.

    2017-07-01

    The universal problem of bacterial resistance to antibiotic reflects a serious threat for physicians to control infections. Evolution in bacteria results in the development of various complex resistance mechanisms to neutralize the bactericidal effect of antibiotics, like drug amelioration, target modification, membrane permeability reduction, and drug extrusion through efflux pumps. Efflux pumps acquire a wide range of substrate specificity and also the tremendous efficacy for drug molecule extrusion outside bacterial cells. Hindrance in the functioning of efflux pumps may rejuvenate the bactericidal effect of conventional antibiotics. Efflux pumps also play an important role in the exclusion or inclusion of quorum-sensing biomolecules responsible for biofilm formation in bacterial cells. This transit movement of quorum-sensing biomolecules inside or outside the bacterial cells may get interrupted by impeding the functioning of efflux pumps. Metallic nanoparticles represent a potential candidate to block efflux pumps of bacterial cells. The application of nanoparticles as efflux pump inhibitors will not only help to revive the bactericidal effect of conventional antibiotics but will also assist to reduce biofilm-forming capacity of microbes. This review focuses on a novel and fascinating application of metallic nanoparticles in synergy with conventional antibiotics for efflux pump inhibition.

  15. [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.

  16. High disease activity is related to low levels of physical activity in patients with ankylosing spondylitis.

    Science.gov (United States)

    Fongen, Camilla; Halvorsen, Silje; Dagfinrud, Hanne

    2013-12-01

    This study aims to compare physical activity (PA) level and exercise habits in patients with ankylosing spondylitis (AS) who have high disease activity with those who have low disease activity and, further, to compare both groups with population controls. Cross-sectional study design was used. The participants include 149 patients (mean age 49.3 (SD 11.1), 61% men, 54% high disease activity) and 133 controls (mean age 52.7 (SD11.3), 58% men). PA was reported with the International PA Questionnaire-Long and results were presented as weekly energy expenditure (metabolic equivalent, MET) in different intensities, domains, and proportion reaching health enhancing physical activity (HEPA). Types of PA were registered in a structured interview. The AS Disease Activity Score was used to assess patients' disease activity. Patients with high disease activity reported significantly lower total weekly energy expenditure (MET) than patients with low disease activity and controls (p = 0.02, p = 0.01, respectively) and lower amounts of walking (p < 0.01, p = 0.02, respectively) and vigorous activity (p = 0.06, p = 0.06, respectively). Only 41% of the patients with high disease activity reached HEPA compared to 61% of the patients with low disease activity (p = 0.02). Patients in general participated less in leisure PA performed outdoor and with higher intensities (MET ≥ 6) than controls.AS patients with high disease activity had lower weekly energy expenditure in PA than patients with low disease activity and controls, and were less likely to reach HEPA than patients with low disease activity. For optimal management, health professionals should focus on physical activity in their consultations with AS patients, especially those with high disease activity.

  17. High Resolution Screening of biologically active compounds and metabolites

    NARCIS (Netherlands)

    Kool, J.

    2007-01-01

    High Resolution Screening of biologically active compounds and metabolites Jeroen Kool Biotransformation enzymes play a crucial role in the metabolism of both endogenous compounds and xenobiotics. Usually, the detoxication of these compounds by biotransformation enzymes results in harmless metab

  18. Green synthesis of Al2O3 nanoparticles and their bactericidal potential against clinical isolates of multi-drug resistant Pseudomonas aeruginosa.

    Science.gov (United States)

    Ansari, Mohammad A; Khan, Haris M; Alzohairy, Mohammad A; Jalal, Mohammad; Ali, Syed G; Pal, Ruchita; Musarrat, Javed

    2015-01-01

    The high prevalence of extended-spectrum β-lactamases (76.3 %) and metallo-β-lactamases (7.3 %) amongst the bacteria Pseudomonas aeruginosa is a critical problem that has set forth an enormous therapeutic challenge. The suggested role of nanoparticles as next generation antibiotics, and inadequate information on antibacterial activity of aluminium oxide nanoparticles has led us to investigate the green synthesis of aluminium oxide nanoparticles (Al2O3 NPs) using leaf extracts of lemongrass and its antibacterial activity against extended-spectrum β-lactamases and metallo-β-lactamases clinical isolates of P. aeruginosa. The synthesized Al2O3-NPs were characterized by scanning electron microcopy, high resolution-transmission electron microscopy, atomic force microscopy, X-ray diffraction, Zeta potential, and differential light scattering techniques. The X-ray diffraction data revealed the average size of the spherical Al2O3-NPs as 34.5 nm. The hydrodynamic size in Milli Q water and Zeta potential were determined to be 254 nm and +52.2 mV, respectively. The minimal inhibitory concentration of Al2O3-NPs was found to be in the range of 1,600-3,200 µg/ml. Treatment at concentrations >2,000 µg/ml, resulted in complete growth inhibition of extended-spectrum β-lactamases and metallo-β-lactamases isolates. Scanning electron microcopy analysis revealed the clusters of nanoparticles attached to the bacterial cell surface, causing structural deformities in treated cells. High resolution-transmission electron microscopy analysis confirmed that nanoparticles crossed the cell membrane to become intracellular. The interaction of nanoparticles with the cell membrane eventually triggered the loss of membrane integrity, most likely due to intracellular oxidative stress. The data explicitly suggested that the synthesized Al2O3-NPs can be exploited as an effective bactericidal agent against extended-spectrum β-lactamases, non-extended-spectrum β-lactamases and metallo

  19. Murine erythrocytes contain high levels of lysophospholipase activity

    NARCIS (Netherlands)

    Kamp, J.A.F. op den; Roelofsen, B.; Sanderink, G.; Middelkoop, E.; Hamer, R.

    1984-01-01

    Murine erythrocytes were found to be unique in the high levels of lysophospholipase activity in the cytosol of these cells. The specific activity of the enzyme in the cytosol of the murine cells is 10-times higher than in the cytosol of rabbit erythrocytes and approximately three orders of magnitude

  20. The bactericidal effects of an acidified sodium chlorite-containing oral moisturizing gel: a pilot study.

    Science.gov (United States)

    Kuroyama, Iwao; Osato, Shigeo; Ogawa, Takahiro

    2013-12-01

    The aim of this study was to examine the bactericidal effects and bactericidal time of an acidified sodium chlorite compound gel (ASC-Gel) on bacteria isolated from the peri-implant sulci of 10 patients who received implants 3-27 years previously, and the depth of each peri-implant sulcus was 5 mm or less. Porphyromonas gingivalis (ATCC33277) was used as the control bacterium. Five ASC-Gel preparations were created by adding 3.3%, 5.0%, 7.0%, 9.0%, and 11.0% citric acid (CA) (condition a, b, c, d, and e, respectively) into an oral moisturizing gel containing sodium chlorite. The concentrations of chlorine dioxide (ClO2) generated in ASC-Gel under conditions (a) to (e) were 12.1, 14.1, 17.2, 21.2, and 39.3 ppm, respectively. We examined the bactericidal effects of the 5 ASC-Gel preparations at volumes of 0.5, 1.0, and 2.0 mL, and measured the bactericidal time when 2.0 mL of ASC-Gel was used under condition (e). The bactericidal effects of ASC-Gel became significantly greater with increased concentrations of CA and ClO2 and with increased usage (0.5-2.0 mL) of the gel. All bacteria were killed by using 2.0 mL of ASC-Gel under condition (e). ASC-Gel also needed between 45 and 90 minutes to kill all microbes under condition (e). Within the limits of the present investigation, these results suggest that ASC-Gel is useful as a chemical disinfectant against bacteria in the peri-implant sulcus. Further studies are also required to protect teeth, the surface of hydroxyapatite-coated implants, and the surrounding soft tissues from effects of chemical dissolution such as acid erosion due to the low pH of ASC-Gel.

  1. The physical activity climate in Minnesota middle and high schools.

    Science.gov (United States)

    Samuelson, Anne; Lytle, Leslie; Pasch, Keryn; Farbakhsh, Kian; Moe, Stacey; Sirard, John Ronald

    2010-11-01

    This article describes policies, practices, and facilities that form the physical activity climate in Minneapolis/St. Paul, Minnesota metro area middle and high schools and examines how the physical activity climate varies by school characteristics, including public/private, school location and grade level. Surveys examining school physical activity practices, policies and environment were administered to principals and physical education department heads from 115 middle and high schools participating in the Transdisciplinary Research on Energetics and Cancer-Identifying Determinants of Eating and Activity (TREC-IDEA) study. While some supportive practices were highly prevalent in the schools studied (such as prohibiting substitution of other classes for physical education); other practices were less common (such as providing opportunity for intramural (noncompetitive) sports). Public schools vs. private schools and schools with a larger school enrollment were more likely to have a school climate supportive of physical activity. Although schools reported elements of positive physical activity climates, discrepancies exist by school characteristics. Of note, public schools were more than twice as likely as private schools to have supportive physical activity environments. Establishing more consistent physical activity expectations and funding at the state and national level is necessary to increase regular school physical activity.

  2. 78 FR 70567 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Final...

    Science.gov (United States)

    2013-11-26

    ...] Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Final Programmatic... Programmatic Environmental Assessment (PEA) for the Nationwide Use of High Frequency (HF) and Ultra High Frequency (UHF) Sound Navigation and Ranging (SONAR) Technology and Finding of No Significant Impact (FONSI...

  3. Nanocharacterization and bactericidal performance of silver modified titania photocatalyst.

    Science.gov (United States)

    Pan, Xubin; Medina-Ramirez, Iliana; Mernaugh, Ray; Liu, Jingbo

    2010-05-01

    An environmental-friendly procedure for manufacturing silver (Ag) and titania (TiO(2)) nanocomposites in an aqueous solution is presented. This green synthetic approach results in the successful production of nanomaterials with high dispersion and crystallinity. The colloidal suspensions of the nanocomposites composed of metal and ceramic (Ag-TiO(2)) were found to be extremely stable over a prolonged time period. Morphologically, nanocomposites were found to be composed of near-spherical particles that were highly crystalline. The nanocomposites were mono-dispersed with particles varying in size from 20 to 50nm, depending upon nanocomposite solution pH. Indexed metallic nanoscale silver exhibited a face-centered cubic (fcc) crystalline phase structure. Nanocomposite elemental composition studies indicated that the molar ratio of Ag and Ti was approximately 1-20. The binding energies and energy differences of Ag, Ti and O were well-indexed with their associated standard spectra. Nanocomposite optical absorption properties were consistent with noble metal nanoparticles. The zetapotential for the nanocomposites was higher at acidic pH and exhibited an absolute negative charge that apparently inhibited particle agglomeration. Escherichia coli (E. coli), a Gram-negative model microorganism was effectively inactivated using the nanocomposites under visible light at ambient temperature and pressure. The 'green chemistry' derived Ag-TiO(2) composites are applicable for the removal of biological impurities from drinking and underground water supplies. The results of the study indicated that nanocomposites could be specifically designed to prevent growth of bacteria in water.

  4. Experimental conditions affecting functional comparison of highly active glutathione transferases.

    Science.gov (United States)

    Fedulova, Natalia; Mannervik, Bengt

    2011-06-01

    Glutathione transferases (GSTs, EC 2.5.1.18) possess multiple functions and have potential applications in biotechnology. Direct evidence of underestimation of activity of human GST A3-3 and porcine GST A2-2 measured at submicromolar enzyme concentrations is reported here for the first time. The combination of time-dependent and enzyme concentration-dependent loss of activity and the choice of the organic solvent for substrates were found to cause irreproducibility of activity measurements of GSTs. These effects contribute to high variability of activity values of porcine GST A2-2 and human Alpha-class GSTs reported in the literature. Adsorption of GSTs to surfaces was found to be the main explanation of the observed phenomena. Several approaches to improved functional comparison of highly active GSTs are proposed.

  5. High Power VCSEL Device with Periodic Gain Active Region

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High power vertical cavity surface emitting lasers(VCSEKLs) with large aperture have been fabricated through improving passivation, lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structures, a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure, with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the ca...

  6. Super-SERS-active and highly effective antimicrobial Ag nanodendrites

    Science.gov (United States)

    Li, H. B.; Liu, P.; Liang, Y.; Xiao, J.; Yang, G. W.

    2012-07-01

    We have developed simple and green electrochemistry to synthesize Ag nanostructures with high purity, good crystallinity and smooth surface for applications as super-SERS (surface-enhanced Raman scattering), SERS-active substrates and with highly effective antimicrobial activities. This synthesis takes place in a clean and slow reaction environment without any chemical additives, which ensures an ultrahigh active surface of the as-synthesized Ag nanostructures owing to their purity, good crystallinity and smooth morphology. Using this method, we synthesized nearly perfect Ag nanodendrites (NDs), which exhibit super-SERS sensitivity when they are used to detect the SERS spectra of rhodamine 6G at concentrations as low as 5 × 10-16 M, and have an ultrahigh electromagnetic (EM) enhancement factor of the order of 1013, breaking through the theoretical limit of EM enhancement. Meanwhile, the as-synthesized Ag NDs possess highly effective antimicrobial activities for Escherichia coli, Candida albicans and Staphylococcus aureus, which are over 10 times that of silver nanoparticles. Additionally, the basic physics and chemistry involved in the fabrication of Ag nanostructures are pursued. These investigations show that silver nanostructures with highly active surfaces can make the most of Ag nanostructures functioning as super-SERS-active substrates and multiple antibiotics.

  7. 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

    OpenAIRE

    ME Álvarez; López, C.; CE Giraldo; Samudio, I; JU Carmona

    2011-01-01

    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...

  8. 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.

  9. Pharmacodynamic modeling of in vitro activity of marbofloxacin against Escherichia coli strains.

    Science.gov (United States)

    Andraud, M; Chauvin, C; Sanders, P; Laurentie, M

    2011-02-01

    A mathematical pharmacodynamic model was developed to describe the bactericidal activity of marbofloxacin against Escherichia coli strains with reduced susceptibility levels (determined using MICs) under optimal and intestinal growth conditions. Model parameters were estimated using nonlinear least-square curve-fitting procedures for each E. coli strain. Parameters related to bactericidal activity were subsequently analyzed using a maximum-effect (E(max)) model adapted to account for a direct and a delayed effect. While net growth rates did not vary significantly with strain susceptibility, culture medium had a major effect. The bactericidal activity of marbofloxacin was closely associated with the concentration and the duration of exposure of the bacteria to the antimicrobial agent. The value of the concentration inducing a half-maximum effect (C(50)) was highly correlated with MIC values (R(2) = 0.87 and R(2) = 0.94 under intestinal and optimal conditions, respectively). Our model reproduced the time-kill kinetics with good accuracy (R(2) of >0.90) and helped explain observed regrowth.

  10. In vitro activity of daptomycin against Enterococcus faecalis under various conditions of growth-phases, inoculum and pH.

    Science.gov (United States)

    Argemi, Xavier; Hansmann, Yves; Christmann, Daniel; Lefebvre, Sophie; Jaulhac, Benoit; Jehl, François

    2013-01-01

    Enterococcus faecalis (E. faecalis) has become a major leading cause of nosocomial endocarditis. Treatment of such infections remains problematic and new therapeutic options are needed. Nine E. faecalis strains were tested: six obtained from patients presenting endocarditis, one with isolated bacteremia, and two reference strains. Antibiotics included daptomycin, alone or in combination, linezolid, tigecycline, rifampicin, gentamicin, teicoplanin, ceftriaxone and amoxicillin. Time-kill studies included colony counts at 1, 4 and 24 h of incubation. Significant bactericidal activity was defined as a decrease of ≥3log10CFU/ml after 24 h of incubation. Antibiotics were tested at a low (10(6) CFU/ml) and high (10(9) CFU/ml) inoculum, against exponential- and stationary-phase bacteria. We also performed time kill studies of chemically growth arrested E. faecalis. Various pH conditions were used during the tests. In exponential growth phase and with a low inoculum, daptomycin alone at 60 µg/ml and the combination amoxicillin-gentamicin both achieved a 4-log10 reduction in one hour on all strains. In exponential growth phase with a high inoculum, daptomycin alone was bactericidal at a concentration of 120 µg/ml. All the combinations tested with this drug were indifferent. In stationary phase with a high inoculum daptomycin remained bactericidal but exhibited a pH dependent activity and slower kill rates. All combinations that did not include daptomycin were not bactericidal in conditions of high inoculum, whatever the growth phase. The results indicate that daptomycin is the only antibiotic that may be able of overcoming the effects of growth phase and high inoculum.

  11. School day segmented physical activity patterns of high and low active children

    Science.gov (United States)

    2012-01-01

    Background Variability exists in children’s activity patterns due to the association with environmental, social, demographic, and inter-individual factors. This study described accelerometer assessed physical activity patterns of high and low active children during segmented school week days whilst controlling for potential correlates. Methods Two hundred and twenty-three children (mean age: 10.7 ± 0.3 yrs, 55.6% girls, 18.9% overweight/obese) from 8 north-west England primary schools wore ActiGraph GT1M accelerometers for 7 consecutive days during autumn of 2009. ActiGraph counts were converted to minutes of moderate (MPA), vigorous (VPA) and moderate-to-vigorous (MVPA) physical activity. Children were classified as high active (HIGH) or low active (LOW) depending on the percentage of week days they accumulated at least 60 minutes of MVPA. Minutes spent in MPA and VPA were calculated for school time and non-school time and for five discrete school day segments (before-school, class time, recess, lunchtime, and after-school). Data were analysed using multi-level modelling. Results The HIGH group spent significantly longer in MPA and/or VPA before-school, during class time, lunchtime, and after-school (P children, playground area per student, and temperature, depending on the segment analysed. The additive effect of the segment differences was that the HIGH group accumulated 12.5 minutes per day more MVPA than the LOW group. Conclusions HIGH active children achieved significantly more MPA and VPA than LOW active during four of the five segments of the school day when analyses were adjusted for potential correlates. Physical activity promotion strategies targeting low active children during discretionary physical activity segments of the day, and particularly via structured afterschool physical activity programs may be beneficial. PMID:22672654

  12. School day segmented physical activity patterns of high and low active children.

    Science.gov (United States)

    Fairclough, Stuart J; Beighle, Aaron; Erwin, Heather; Ridgers, Nicola D

    2012-06-06

    Variability exists in children's activity patterns due to the association with environmental, social, demographic, and inter-individual factors. This study described accelerometer assessed physical activity patterns of high and low active children during segmented school week days whilst controlling for potential correlates. Two hundred and twenty-three children (mean age: 10.7 ± 0.3 yrs, 55.6% girls, 18.9% overweight/obese) from 8 north-west England primary schools wore ActiGraph GT1M accelerometers for 7 consecutive days during autumn of 2009. ActiGraph counts were converted to minutes of moderate (MPA), vigorous (VPA) and moderate-to-vigorous (MVPA) physical activity. Children were classified as high active (HIGH) or low active (LOW) depending on the percentage of week days they accumulated at least 60 minutes of MVPA. Minutes spent in MPA and VPA were calculated for school time and non-school time and for five discrete school day segments (before-school, class time, recess, lunchtime, and after-school). Data were analysed using multi-level modelling. The HIGH group spent significantly longer in MPA and/or VPA before-school, during class time, lunchtime, and after-school (P children, playground area per student, and temperature, depending on the segment analysed.The additive effect of the segment differences was that the HIGH group accumulated 12.5 minutes per day more MVPA than the LOW group. HIGH active children achieved significantly more MPA and VPA than LOW active during four of the five segments of the school day when analyses were adjusted for potential correlates. Physical activity promotion strategies targeting low active children during discretionary physical activity segments of the day, and particularly via structured afterschool physical activity programs may be beneficial.

  13. School day segmented physical activity patterns of high and low active children

    Directory of Open Access Journals (Sweden)

    Fairclough Stuart J

    2012-06-01

    Full Text Available Abstract Background Variability exists in children’s activity patterns due to the association with environmental, social, demographic, and inter-individual factors. This study described accelerometer assessed physical activity patterns of high and low active children during segmented school week days whilst controlling for potential correlates. Methods Two hundred and twenty-three children (mean age: 10.7 ± 0.3 yrs, 55.6% girls, 18.9% overweight/obese from 8 north-west England primary schools wore ActiGraph GT1M accelerometers for 7 consecutive days during autumn of 2009. ActiGraph counts were converted to minutes of moderate (MPA, vigorous (VPA and moderate-to-vigorous (MVPA physical activity. Children were classified as high active (HIGH or low active (LOW depending on the percentage of week days they accumulated at least 60 minutes of MVPA. Minutes spent in MPA and VPA were calculated for school time and non-school time and for five discrete school day segments (before-school, class time, recess, lunchtime, and after-school. Data were analysed using multi-level modelling. Results The HIGH group spent significantly longer in MPA and/or VPA before-school, during class time, lunchtime, and after-school (P P  The additive effect of the segment differences was that the HIGH group accumulated 12.5 minutes per day more MVPA than the LOW group. Conclusions HIGH active children achieved significantly more MPA and VPA than LOW active during four of the five segments of the school day when analyses were adjusted for potential correlates. Physical activity promotion strategies targeting low active children during discretionary physical activity segments of the day, and particularly via structured afterschool physical activity programs may be beneficial.

  14. 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.

  15. Synthesis, Characterizations of Superparamagnetic Fe3O4-Ag Hybrid Nanoparticles and Their Application for Highly Effective Bacteria Inactivation.

    Science.gov (United States)

    Tung, Le Minh; Cong, Nguyen Xuan; Huy, Le Thanh; Lan, Nguyen Thi; Phan, Vu Ngoc; Hoa, Nguyen Quang; Vinh, Le Khanh; Thinh, Nguyen Viet; Tai, Le Thanh; Ngo, Duc-The; Mølhave, Kristian; Huy, Tran Quang; Le, Anh-Tuan

    2016-06-01

    In recent years, outbreaks of infectious diseases caused by pathogenic micro-organisms pose a serious threat to public health. In this work, Fe3O4-Ag hybrid nanoparticles were synthesized by simple chemistry method and these prepared nanoparticles were used to investigate their antibacterial properties and mechanism against methicilline-resistant Staphylococcus aureus (MRSA) pathogen. The formation of dimer-like nanostructure of Fe3O4-Ag hybrid NPs was confirmed by X-ray diffraction and High-resolution Transmission Electron Microscopy. Our biological analysis revealed that the Fe3O4-Ag hybrid NPs showed more noticeable bactericidal activity than that of plain Fe3O4 NPs and Ag-NPs. We suggest that the enhancement in bactericidal activity of Fe3O4-Ag hybrid NPs might be likely from main factors such as: (i) enhanced surface area property of hybrid nanoparticles; (ii) the high catalytic activity of Ag-NPs with good dispersion and aggregation stability due to the iron oxide magnetic carrier, and (iii) large direct physical contacts between the bacterial cell membrane and the hybrid nanoparticles. The superparamagnetic hybrid nanoparticles of iron oxide magnetic nanoparticles decorated with silver nanoparticles can be a potential candidate to effectively treat infectious MRSA pathogen with recyclable capability, targeted bactericidal delivery and minimum release into environment.

  16. The effect of varying acidity on helicobacter pylori growth and the bactericidal efficacy of ampicillin

    Science.gov (United States)

    Marcus, Elizabeth A.; Inatomi, Nobuhiro; Nagami, Glenn T.; Sachs, George; Scott, David R.

    2012-01-01

    Summary Background Penicillins inhibit cell wall synthesis; therefore, H. pylori must be dividing for this class of antibiotics to be effective in eradication therapy. Identifying growth responses to varying medium pH may allow design of more effective treatment regimens. Aim To determine the effect of acidity on bacterial growth and the bactericidal efficacy of ampicillin. Methods H. pylori were incubated in dialysis chambers suspended in 1.5L of media at various pHs with 5mM urea, with or without ampicillin, for 4, 8 or 16 hours, thus mimicking unbuffered gastric juice. Changes in gene expression, viability and survival were determined. Results At pH 3.0, but not at pH 4.5 or 7.4, there was decreased expression of ~400 genes, including many cell envelope biosynthesis, cell division and penicillin-binding protein genes. Ampicillin was bactericidal at pH 4.5 and 7.4 but not at pH 3.0. Conclusion Ampicillin is bactericidal at pH 4.5 and 7.4, but not at pH 3.0, due to decreased expression of cell envelope and division genes with loss of cell division at pH 3.0. Therefore, at pH 3.0, the likely pH at the gastric surface, the bacteria are non-dividing and persist with ampicillin treatment. A more effective inhibitor of acid secretion that maintains gastric pH near neutrality for 24 hours/day should enhance the efficacy of amoxicillin, improving triple therapy and likely even allowing dual amoxicillin based therapy for H. pylori eradication. PMID:23009227

  17. Recommendations of activity restriction in high-risk pregnancy scenarios

    DEFF Research Database (Denmark)

    Bendix, Jane; Hegaard, Hanne Kristine; Bergholt, Thomas;

    2015-01-01

    obstetricians and midwives prescribe activity restriction in most high-risk pregnancies. The degree of activity restriction and the presumed effect vary between clinicians. This may reflect different attitudes and lack of guidelines based on clinical studies of a possible benefit of activity restriction....... to the obstetricians, the midwives also reported that they expected the recommendation to be more effective. Most midwives and obstetricians reported that they thought strict activity restriction was associated with severe or moderate adverse effect, and recommended antithrombotic prophylaxis. Conclusions: Danish......Abstract Aims: To describe specific recommendations of activity restriction, place of care, expected beneficial and adverse effects, and recommended antithrombotic prophylaxis in nine clinical scenarios. Methods: A national survey. All members of the Danish Society of Obstetrics and Gynaecology...

  18. High lightning activity in maritime clouds near Mexico

    Directory of Open Access Journals (Sweden)

    B. Kucienska

    2012-01-01

    Full Text Available Lightning activity detected by the World Wide Lightning Location Network (WWLLN over oceanic regions adjacent to Mexico is often as high as that observed over the continent. In order to explore the possible cause of the observed high flash density over those regions, the relationships between lightning, rainfall, vertical hydrometeor profiles, latent heating, wind variability and aerosol optical thickness are analyzed. The characteristics of lightning and precipitation over four oceanic zones adjacent to Mexican coastlines are contrasted against those over the continent. In addition, we compare two smaller regions over the Tropical Pacific Ocean: one located within the Inter-Tropical Converge Zone and characterized by high rainfall and weak lightning activity and the other influenced by a continental jet and presenting high rainfall and strong lightning activity over the Gulf of Tehuantepec. Maritime precipitating clouds that develop within the region influenced by offshore winds exhibit similar properties to continental clouds: large content of precipitation ice and an increased height range of coexistence of precipitation ice and cloud water. During the rainy season, monthly distribution of lightning within the region influenced by the continental jet is contrary to that of rainfall. Moreover, the monthly variability of lightning is very similar to the variability of the meridional wind component and it is also related to the variability of aerosol optical depth. The analysis strongly suggests that the high lightning activity observed over the Gulf of Tehuantepec is caused by continental cloud condensation nuclei advected over the ocean.

  19. Comparative Activities of Cattle and Swine Platelet Microbicidal Proteins.

    Science.gov (United States)

    Ivanov, Iuri B; Gritsenko, Viktor A

    2009-12-01

    The bactericidal activities of cattle and swine platelet microbicidal proteins (PMPs) with their comparison with human PMP were studied. Activities of PMP were tested against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus lysodeikticus and Escherichia coli. B. subtilis and B. cereus were high susceptible to PMP at very low concentrations. Of the gram-positive cocci studied, M. lysodeikticus and S. aureus were the most, and S. epidermidis the least, susceptible. E. coli was found to be relatively resistant to the lethal action of all PMP. The findings of this study confirm that the existence of antimicrobial peptides is conserved among mammalian platelets.

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

    Science.gov (United States)

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

    2016-03-04

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

  1. Identifying High School Physical Education Physical Activity Patterns after High School

    Science.gov (United States)

    Barney, David; Pleban, Francis T.; Wilkinson, Carol; Prusak, Keven A.

    2015-01-01

    National standards for physical education (PE) encompass five principles for the purpose of defining what high school students should recognize and be able to perform as a result of a quality PE program. The expectation is that youth will develop an active, healthy lifestyle into adulthood from activities and skills taught in PE. Researchers from…

  2. Physical Activity in High School during "Free-Time" Periods

    Science.gov (United States)

    Silva, Pedro; Sousa, Michael; Sá, Carla; Ribeiro, José; Mota, Jorge

    2015-01-01

    The purpose of this study was to examine youth physical activity (PA) in free-time periods during high school days and their contribution to total PA. Differences in terms of sex, age, body mass index and school level were assessed in a sample of Portuguese adolescents. Participants totalled 213 (135 girls), aged 14.6 ± 1.7, from two different…

  3. High Frequency State-Variable Biquadratic Active Filters

    Directory of Open Access Journals (Sweden)

    T. Dostal

    1998-04-01

    Full Text Available The state-variable (KHN active RC biquadratic filters with good performance in high frequency range , flexibility of outputs (LP, HP, BP, low sensitivities in novel current and hybrid modes, using current conveyors, transimpedance, trans-admittance and current operational amplifiers, are given in this paper.

  4. High hydrostatic pressure treatment of porcine oocytes induces parthenogenetic activation

    DEFF Research Database (Denmark)

    Lin, Lin; Pribenszky, Csaba; Molnár, Miklós

    2010-01-01

    An innovative technique called high hydrostatic pressure (HHP) treatment has recently been reported to improve the cryosurvival of gametes and embryos in certain mammalian species, including the mouse, pig, and cattle. In the present study the parthenogenetic activation (PA) of pig oocytes caused...

  5. Reduced autonomic activity during stepwise exposure to high altitude

    NARCIS (Netherlands)

    Sevre, K; Bendz, B; Hanko, E; Nakstad, AR; Hauge, A; Kasin, JI; Lefrandt, JD; Smit, AJ; Eide, [No Value; Rostrup, M

    2001-01-01

    Several studies have shown increased sympathetic activity during acute exposure to hypobaric hypoxia. In a recent field study we found reduced plasma catecholamines during the first days after a stepwise ascent to high altitude. In the present study 14 subjects were exposed to a simulated ascent in

  6. Development activities of the high heat flux scraper element

    Energy Technology Data Exchange (ETDEWEB)

    Boscary, J., E-mail: jean.boscary@ipp.mpg.de [Max Planck Institute for Plasma Physics, Garching (Germany); Lore, J.; Lumsdaine, A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Maier, M. [Max Planck Institute for Plasma Physics, Garching (Germany); McGinnis, D. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Peacock, A.; Tretter, J. [Max Planck Institute for Plasma Physics, Garching (Germany)

    2015-10-15

    The function of the high heat flux scraper element is to reduce the heat loads on the element ends of the actively cooled divertor of Wendelstein 7-X. The scraper element is actively water cooled to remove up to 550 kW steady state power load, with localized heat fluxes as high as 20 MW/m{sup 2}. Its surface area, 0.17 m{sup 2}, is contoured to optimally intercept both upstream and downstream particle fluxes. The plasma facing surface is made of 24 individual scraper fingers based on the monoblock technology. Each scraper finger is 247 mm long and 28 mm wide and has 13 monoblocks made of CFC NB31 bonded by hot isostatic pressing onto a CuCrZr cooling tube equipped with a copper twisted tape. Development activities, described here, include the design and fabrication of prototypes to validate the different technologies selected for the scraper element design to prepare a possible production.

  7. Review of actuators for high speed active flow control

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; LUO ZhenBing; XIA ZhiXun; LIU Bing; DENG Xiong

    2012-01-01

    Actuators are one of the key points for the development of active flow control technology.Efficient methods of high speed flow control can provide enhanced propulsive efficiency and at the same time enable safe and maneuverable high speed flight.The development of high speed flight technology promotes the emergence of novel and robust actuators.This review introduces the state of the art in the development of actuators that can be used in high speed active flow control.The classification and different operation criteria of the actuators are discussed.The specifications,mechanisms and applications of various popular actuator types including fluidic,mechanical,and plasma actuators are described.Based on the realistic need of high speed flow control and the existing results of actuators,a new actuator design method is proposed.At last,the merits and drawbacks of the actuators are summarized and some suggestions on the development of active flow control technology are put forward.

  8. High efficiency cell-specific targeting of cytokine activity

    Science.gov (United States)

    Garcin, Geneviève; Paul, Franciane; Staufenbiel, Markus; Bordat, Yann; van der Heyden, José; Wilmes, Stephan; Cartron, Guillaume; Apparailly, Florence; de Koker, Stefaan; Piehler, Jacob; Tavernier, Jan; Uzé, Gilles

    2014-01-01

    Systemic toxicity currently prevents exploiting the huge potential of many cytokines for medical applications. Here we present a novel strategy to engineer immunocytokines with very high targeting efficacies. The method lies in the use of mutants of toxic cytokines that markedly reduce their receptor-binding affinities, and that are thus rendered essentially inactive. Upon fusion to nanobodies specifically binding to marker proteins, activity of these cytokines is selectively restored for cell populations expressing this marker. This ‘activity-by-targeting’ concept was validated for type I interferons and leptin. In the case of interferon, activity can be directed to target cells in vitro and to selected cell populations in mice, with up to 1,000-fold increased specific activity. This targeting strategy holds promise to revitalize the clinical potential of many cytokines.

  9. 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

  10. Business cycle and innovation activity in medium-high and high technology industry in Poland

    Directory of Open Access Journals (Sweden)

    Dzikowski Piotr

    2015-12-01

    Full Text Available This article examines differences in an impact of business cycle phases on innovation activity in medium-high and high technology industry in Poland. It is assumed that each business cycle phase influences innovation activity in the same fashion, but its impact varies and it depends on the firm’s innovation activity. The higher innovation activity the less impact of business cycle. The scope of the survey relates to innovation in MHT and HT industry in Poland. The data concerns the innovation at the firm level and the diffusion “new for the company”. Innovation activity is defined by the following activities: (1 expenditure on research and development and investments in fixed assets not used so far such as: abuildings, premises and land; b machinery and equipment, c computer software; (2 implementation of new products and technological processes and (3 innovation cooperation. The methodological part of the analysis includes a logit modeling. The survey includes 1355 companies. Business cycle has a great influence on innovation activity in MTH and HT industry in Poland. The influence of recovery phase is positive whereas both stagnation and recession phases decrease the probability of innovation activity. The character of influence depends on the propensity to take innovation activity. The higher level of innovation activity the enterprises present the less influence of business cycle they get.

  11. Meningococcal omp85 in detergent-extracted outer membrane vesicle vaccines induces high levels of non-functional antibodies in mice.

    Science.gov (United States)

    Wedege, E; Lie, K; Bolstad, K; Weynants, V E; Halstensen, A; Herstad, T K; Kreutzberger, J; Nome, L; Naess, L M; Aase, A

    2013-06-01

    The vaccine potential of meningococcal Omp85 was studied by comparing the immune responses of genetically modified deoxycholate-extracted outer membrane vesicles, expressing five-fold higher levels of Omp85, with wild-type vesicles. Groups (n = 6-12) of inbred and outbred mouse strains (Balb/c, C57BL/6, OFI and NMRI) were immunized with the two vaccines, and the induced antibody levels and bactericidal and opsonic activities measured. Except for Balb/c mice, which were low responders, the genetically modified vaccine raised high Omp85 antibody levels in all mouse strains. In comparison, the wild-type vaccine gave lower antibody levels, but NMRI mice responded to this vaccine with the same high levels as the modified vaccine in the other strains. Although the vaccines induced strain-dependent Omp85 antibody responses, the mouse strains showed high and similar serum bactericidal titres. Titres were negligible with heterologous or PorA-negative meningococcal target strains, demonstrating the presence of the dominant bactericidal PorA antibodies. The two vaccines induced the same opsonic titres. Thus, the genetically modified vaccine with high Omp85 antibody levels and the wild-type vaccine induced the same levels of functional activities related to protection against meningococcal disease, suggesting that meningococcal Omp85 is a less attractive vaccine antigen. © 2013 The Authors. Scandinavian Journal of Immunology © 2013 Blackwell Publishing Ltd.

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

    Science.gov (United States)

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

    2014-04-01

    The bone graft-associated infection is widely considered in orthopedic surgery, which may lead to implant failure, extensive bone debridement, and increased patient morbidity. In this study, we fabricated ZSM-5 zeolites for drug delivery systems by hydrothermal method. The structure, morphology, biocompatibility, drug delivery property, and bactericidal property of the ZSM-5 zeolites were investigated. The ZSM-5 zeolites have mordenite framework inverted-type structure and exhibit the disk-like shape with the diameter of ∼350 nm and thickness of ∼165 nm. The biocompatibility tests indicate that human bone marrow stromal cells spread out well on the surfaces of the ZSM-5 zeolites and proliferate significantly with increasing culture time. As compared with the conventional hydroxyapatite particles, the ZSM-5 zeolites possess greater drug loading efficiency and drug sustained release property because of the ordered micropores, large Brunauer-Emmett-Teller (BET) surface areas, and functional groups. For the gentamicin-loaded ZSM-5 zeolites, the sustained release of gentamicin minimizes significantly bacterial adhesion and prevents biofilm formation against Staphylococcus epidermidis. The excellent biocompatibility, drug delivery property, and bactericidal property of the ZSM-5 zeolites suggest that they have great application potentials for treating implant-associated infections. Copyright © 2013 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    1995-12-01

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

  14. [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.

  15. 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.

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

    Science.gov (United States)

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

    2015-03-01

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

  17. 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.

  18. Physical properties of highly active liquor containing molybdate solids

    Energy Technology Data Exchange (ETDEWEB)

    Dunnett, B.; Ward, T.; Roberts, R. [National Nuclear Laboratory, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom); Cheeseright, J. [Sellafield Ltd, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom)

    2016-07-01

    The reprocessing of irradiated nuclear fuel at Sellafield produces a nitric acid based Highly Active Liquor (HAL) waste. The liquor, containing fission products and process additives, is concentrated in an evaporator in order to reduce the volume and is then stored in Highly Active Storage Tanks (HASTs) prior to vitrification. Caesium phosphomolybdate (CPM) is precipitated during the evaporation process and can convert to zirconium molybdate (ZM) during storage. During Post Operational Clean Out (POCO) of the HASTs, it is expected that their highly active content will be reduced by repeated cycles of washing using nitric acid and other reagents. Initial washings are likely to have a chemical composition comparable to concentrated HAL, becoming more dilute during the wash-out process. It is expected that the wash-out process will also recover significant quantities of molybdate solids (ZM, CPM or a mixture) from the HASTs. In order to determine the processing challenges from such washings during POCO, the physical properties of varying concentrations of non-active HAL simulants containing molybdate solids have recently been measured by the UK's National Nuclear Laboratory. The following measurements are presented and discussed: Particle size distribution; Density; Settling behaviour of solids; Voidage of settled sediment beds; Viscosity; Yield stress; And influence of ZM morphology on physical properties. (authors)

  19. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  20. Antimicrobial activity of essential oil components against potential food spoilage microorganisms.

    Science.gov (United States)

    Klein, G; Rüben, C; Upmann, M

    2013-08-01

    The antimicrobial activity of six essential oil components against the potential food spoilage bacteria Aeromonas (A.) hydrophila, Escherichia (E.) coli, Brochothrix (B.) thermosphacta, and Pseudomonas (P.) fragi at single use and in combination with each other was investigated. At single use, the most effective oil components were thymol (bacteriostatic effect starting from 40 ppm, bactericidal effect with 100 ppm) and carvacrol (50 ppm/100 ppm), followed by linalool (180 ppm/720 ppm), α-pinene (400 ppm/no bactericidal effect), 1,8-cineol (1,400 ppm/2,800 ppm), and α-terpineol (600 ppm/no bactericidal effect). Antimicrobial effects occurred only at high, sensorial not acceptable concentrations. The most susceptible bacterium was A. hydrophila, followed by B. thermosphacta and E. coli. Most of the essential oil component combinations tested showed a higher antimicrobial effect than tested at single use. Antagonistic antimicrobial effects were observed particularly against B. thermosphacta, rarely against A. hydrophila. The results show that the concentration of at least one of the components necessary for an antibacterial effect is higher than sensorial acceptable. So the use of herbs with a high content of thymol, carvacrol, linalool, 1,8-cineol, α-pinene or α-terpineol alone or in combination must be weighted against sensorial quality.

  1. High lightning activity in maritime clouds near Mexico

    Science.gov (United States)

    Kucienska, B.; Raga, G. B.; Romero-Centeno, R.

    2012-09-01

    Lightning activity detected by the World Wide Lightning Location Network (WWLLN) over oceanic regions adjacent to Mexico is often as high as that observed over the continent. In order to explore the possible causes of the observed high flash density over those regions, the relationships between lightning, rainfall, vertical hydrometeor profiles, latent heating, wind variability and aerosol optical depth are analyzed. The characteristics of lightning and precipitation over four oceanic zones adjacent to Mexican coastlines are contrasted against those over the continent. The number of flashes per rainfall over some coastal maritime regions is found to be higher than over the continent. The largest number of flashes per rainfall is observed during the biomass burning season. In addition, we compare two smaller areas of the Tropical Pacific Ocean: one located within the Inter-Tropical Convergence Zone and characterized by high rainfall and weak lightning activity and the other one influenced by a continental wind jet and characterized by high rainfall and strong lightning activity. During the rainy season, the monthly distribution of lightning within the region influenced by the continental wind jet is contrary to that of rainfall. Moreover, the monthly variability of lightning is very similar to the variability of the meridional wind component and it is also related to the variability of aerosol optical depth. The analysis suggests that the high lightning activity observed over coastal Pacific region is linked to the continental cloud condensation nuclei advected over the ocean. Analysis of daily observations indicates that the greatest lightning density is observed for moderate values of the aerosol optical depth, between 0.2 and 0.35.

  2. A simple and highly effective process for the preparation of activated carbons with high surface area

    Energy Technology Data Exchange (ETDEWEB)

    Li Ying, E-mail: liyingjlu@163.com [College of Chemistry, Jilin University, Changchun 130012 (China); Ding Xuefeng; Guo Yupeng; Wang Lili; Rong Chunguang; Qu Yuning; Ma Xiaoyu [College of Chemistry, Jilin University, Changchun 130012 (China); Wang Zichen, E-mail: wangzc@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-06-15

    Highlights: {yields} High surface area activated carbon can be prepared by rice husk H{sub 3}PO{sub 4} without pretreatment. {yields} The characteristics of the activated carbon were greatly influenced by post-processing method. {yields} The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. {yields} Some silica in rice husk reacted with H{sub 3}PO{sub 4} to form SiP{sub 2}O{sub 7} which could be removed by post-process. - Abstract: Activated carbons with high surface area were prepared by phosphoric acid as activation agent and rice husks as precursors. It was found that the characteristics of the activated carbons were influenced not only by the preparation but also by the post-processing method. The high surface area of the activated carbons was prepared under the optimum condition (50% H{sub 3}PO{sub 4} with impregnation ratio of 5:1, activation temperature of 500 deg. C, activation time of 0.5 h, wash water temperature of 100 deg. C). SiO{sub 2} content could affect the surface area of activated carbons, either. The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. The SiO{sub 2} content was 11.2% when used the optimum condition. The explanation was that silicon element in rice husks reacted with H{sub 3}PO{sub 4} to form silicon phosphate (SiP{sub 2}O{sub 7}), and it could be proved further by X-ray diffraction analysis, SiP{sub 2}O{sub 7} could be removed by post-process.

  3. Biological Activity of Sour Cherry Fruit on the Bacterial Flora of Human Saliva in vitro

    Directory of Open Access Journals (Sweden)

    Anna Blázovics

    2012-01-01

    Full Text Available This study is the first report on the antibacterial effect of Hungarian sour cherry cultivars. Biological activity of sour cherry juices prepared from fruits Érdi jubileum, Érdi bőtermő, Maliga emléke and Kántorjánosi 3 harvested at different maturity stages was investigated on bacteria present in human saliva. The influence of sour cherry on a mixed bacterial flora of human saliva of 10 volunteers was determined by different experimental approaches. Bactericidal effects were evaluated by minimum inhibitory concentration (MIC using agar diffusion methods and by minimum bactericidal dilution (MBD assays counting the number of surviving bacterial cells in the diluted juices. Time-dependent antibacterial effects were also determined by monitoring the decrease in bacterial cell numbers after the treatment with undiluted juices. The investigated sour cherry juices displayed an impressive bactericidal effect against human saliva bacteria (10–100× reduction of cell numbers within a short time frame (10–40 min. Érdi jubileum was more effective (100 000× reduction of cell number after 270 min than the other studied cultivars. Bactericidal effect was influenced by ripening of samples of Érdi jubileum obtained at different harvesting dates. Biologically active components were effective against a large spectrum of opportunistic bacterial pathogens such as Pseudomonas, Klebsiella, Pantoea spp. and Escherichia coli, including the antibiotic-resistant Pseudomonas aeruginosa but they were ineffective against beneficial probiotic Lactobacillus spp. Results confirmed the antibacterial potential of all the investigated sour cherry fruits, therefore the consumption of the fruit or its juice for positive influence on oral hygiene is highly recommended.

  4. Active Photonic crystal fibers for high power applications

    DEFF Research Database (Denmark)

    Olausson, Christina Bjarnal Thulin

    . This plays an important role in high power lasers and ampliers with respect to efficiency, packaging, and thermal handling. The third part of the work has involved developing tools for characterizing the mode quality and stability of large core bers. Stable, single-mode bers with larger cores are essential......The photonic crystal ber technology provides means to realize bers optimized for high power operation, due to the large single-mode cores and the unique design exibility of the microstructure. The work presented in this thesis focuses on improving the properties of active photonic crystal bers...... for high power ber lasers and ampliers, and on adding new functionality to the fibers - all with the purpose of pushing the technology towards high powers. The first part of the work has been to investigate photo darkening, the mitigation of which is crucial in the quest for higher powers. The work has...

  5. Preclinical Study for Application of Fabricated High Activity Ir-192

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Mi Son; Kang, Seung Hee; Oh, Young Taek; Jeong, Chul; Kim, Mi Hwa; Hwang, Jeong Hye; Kim, Hee Seong; Im, Eun Jeong [Ajou University, Suwon (Korea, Republic of)

    2005-10-15

    This study was performed to evaluate the feasibility and safety of high activity Ir-192 sources manufactured by KAERI(Korea Atomic Energy Research Institute) for application to present equipment such as various applicators inserted to patients and PLATO(Nucletron, Netherland) of treatment planning system and to evaluate safety and accuracy of Ir-192 as practical clinic use through in vitro dosimetry of Ir-192. We confirmed the physical and radiobiological safety of KAERI sources to use practical. KAERI sources are applicable to commercial high dose rate brachytherapy machine safely. Then those can be substituted for the imported sources such as sources made by Nucletron, Gammamed and exported to the foreign country

  6. Activated blended cement containing high volume coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Shi, C.J.; Qian, J.S. [CJS Technology Inc., Burlington, ON (Canada)

    2001-10-01

    This study investigated the strength and equilibrium water extraction of blended cement containing high volume coal fly ash and activator CaCl{sub 2}. The addition of CaCl{sub 2} increased the strength of cement very significantly. Equilibrium water extraction indicated that the addition of CaCl{sub 2} decreased the pH of the pore solution, but accelerated the pozzolanic reactions between coal fly ash and lime, which became more obvious when the volume of fly ash in the cement was increased from 50-70%. Results from both strength and water extraction testing could conclude that CaCl{sub 2} is a good activator for the activation of pozzolanic reactivity of fly ash and for the improvement of early properties of fly ash cement and concrete.

  7. Accelerator Production and Separations for High Specific Activity Rhenium-186

    Energy Technology Data Exchange (ETDEWEB)

    Jurisson, Silvia S. [Univ. of Missouri, Columbia, MO (United States); Wilbur, D. Scott [Univ. of Washington, Seattle, WA (United States)

    2016-04-01

    Tungsten and osmium targets were evaluated for the production of high specific activity rhenium-186. Rhenium-186 has potential applications in radiotherapy for the treatment of a variety of diseases, including targeting with monoclonal antibodies and peptides. Methods were evaluated using tungsten metal, tungsten dioxide, tungsten disulfide and osmium disulfide. Separation of the rhenium-186 produced and recycling of the enriched tungsten-186 and osmium-189 enriched targets were developed.

  8. Bactericidal/permeability-increasing protein (rBPI21) and fluoroquinolone mitigate radiation-induced bone marrow aplasia and death.

    Science.gov (United States)

    Guinan, Eva C; Barbon, Christine M; Kalish, Leslie A; Parmar, Kalindi; Kutok, Jeff; Mancuso, Christy J; Stoler-Barak, Liat; Suter, Eugénie E; Russell, Janice D; Palmer, Christine D; Gallington, Leighanne C; Voskertchian, Annie; Vergilio, Jo-Anne; Cole, Geoffrey; Zhu, Kaya; D'Andrea, Alan; Soiffer, Robert; Weiss, Jerrold P; Levy, Ofer

    2011-11-23

    Identification of safe, effective treatments to mitigate toxicity after extensive radiation exposure has proven challenging. Only a limited number of candidate approaches have emerged, and the U.S. Food and Drug Administration has yet to approve any agent for a mass-casualty radiation disaster. Because patients undergoing hematopoietic stem cell transplantation undergo radiation treatment that produces toxicities similar to radiation-disaster exposure, we studied patients early after such treatment to identify new approaches to this problem. Patients rapidly developed endotoxemia and reduced plasma bactericidal/permeability-increasing protein (BPI), a potent endotoxin-neutralizing protein, in association with neutropenia. We hypothesized that a treatment supplying similar endotoxin-neutralizing activity might replace the BPI deficit and mitigate radiation toxicity and tested this idea in mice. A single 7-Gy radiation dose, which killed 95% of the mice by 30 days, was followed 24 hours later by twice-daily, subcutaneous injections of the rec