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1

REPORT ANTIBACTERIAL ACTIVITY OF OREGANO (ORIGANUM VULGARE LINN.) AGAINST GRAM POSITIVE BACTERIA  

Microsoft Academic Search

The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium,

SABAHAT SAEED; PERWEEN TARIQ

2

Antibacterial activity of oregano (Origanum vulgare Linn.) against gram positive bacteria.  

PubMed

The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium, B. thuringiensis, B. alvei, B. circulans, B. brevis, B. coagulans, B. pumilus, B. laterosporus, B. polymyxa, B. macerans, B. subtilis, B. firmus, B. cereus and B. lichiniformis. The infusion exhibited maximum activity against B. laterosporus (17.5 mm mean zone of inhibition+/-1.5 Standard deviation) followed by B. polymyxa (17.0 mm+/-2.0 SD) and essential oil of oregano exhibited maximum activity against S. saprophyticus (16.8 mm+/-1.8 SD) followed by B. circulans (14.5 mm+/-0.5 SD). While all these tested isolates were found resistant to decoction of oregano. PMID:19783523

Saeed, Sabahat; Tariq, Perween

2009-10-01

3

Antibacterial Activity of Sphingoid Bases and Fatty Acids against Gram-Positive and Gram-Negative Bacteria  

PubMed Central

There is growing evidence that the role of lipids in innate immunity is more important than previously realized. How lipids interact with bacteria to achieve a level of protection, however, is still poorly understood. To begin to address the mechanisms of antibacterial activity, we determined MICs and minimum bactericidal concentrations (MBCs) of lipids common to the skin and oral cavity—the sphingoid bases d-sphingosine, phytosphingosine, and dihydrosphingosine and the fatty acids sapienic acid and lauric acid—against four Gram-negative bacteria and seven Gram-positive bacteria. Exact Kruskal-Wallis tests of these values showed differences among lipid treatments (P < 0.0001) for each bacterial species except Serratia marcescens and Pseudomonas aeruginosa. d-Sphingosine (MBC range, 0.3 to 19.6 ?g/ml), dihydrosphingosine (MBC range, 0.6 to 39.1 ?g/ml), and phytosphingosine (MBC range, 3.3 to 62.5 ?g/ml) were active against all bacteria except S. marcescens and P. aeruginosa (MBC > 500 ?g/ml). Sapienic acid (MBC range, 31.3 to 375.0 ?g/ml) was active against Streptococcus sanguinis, Streptococcus mitis, and Fusobacterium nucleatum but not active against Escherichia coli, Staphylococcus aureus, S. marcescens, P. aeruginosa, Corynebacterium bovis, Corynebacterium striatum, and Corynebacterium jeikeium (MBC > 500 ?g/ml). Lauric acid (MBC range, 6.8 to 375.0 ?g/ml) was active against all bacteria except E. coli, S. marcescens, and P. aeruginosa (MBC > 500 ?g/ml). Complete killing was achieved as early as 0.5 h for some lipids but took as long as 24 h for others. Hence, sphingoid bases and fatty acids have different antibacterial activities and may have potential for prophylactic or therapeutic intervention in infection.

Fischer, Carol L.; Drake, David R.; Dawson, Deborah V.; Blanchette, Derek R.; Brogden, Kim A.

2012-01-01

4

Antibacterial activity of sphingoid bases and fatty acids against Gram-positive and Gram-negative bacteria.  

PubMed

There is growing evidence that the role of lipids in innate immunity is more important than previously realized. How lipids interact with bacteria to achieve a level of protection, however, is still poorly understood. To begin to address the mechanisms of antibacterial activity, we determined MICs and minimum bactericidal concentrations (MBCs) of lipids common to the skin and oral cavity--the sphingoid bases D-sphingosine, phytosphingosine, and dihydrosphingosine and the fatty acids sapienic acid and lauric acid--against four Gram-negative bacteria and seven Gram-positive bacteria. Exact Kruskal-Wallis tests of these values showed differences among lipid treatments (P < 0.0001) for each bacterial species except Serratia marcescens and Pseudomonas aeruginosa. D-sphingosine (MBC range, 0.3 to 19.6 ?g/ml), dihydrosphingosine (MBC range, 0.6 to 39.1 ?g/ml), and phytosphingosine (MBC range, 3.3 to 62.5 ?g/ml) were active against all bacteria except S. marcescens and P. aeruginosa (MBC > 500 ?g/ml). Sapienic acid (MBC range, 31.3 to 375.0 ?g/ml) was active against Streptococcus sanguinis, Streptococcus mitis, and Fusobacterium nucleatum but not active against Escherichia coli, Staphylococcus aureus, S. marcescens, P. aeruginosa, Corynebacterium bovis, Corynebacterium striatum, and Corynebacterium jeikeium (MBC > 500 ?g/ml). Lauric acid (MBC range, 6.8 to 375.0 ?g/ml) was active against all bacteria except E. coli, S. marcescens, and P. aeruginosa (MBC > 500 ?g/ml). Complete killing was achieved as early as 0.5 h for some lipids but took as long as 24 h for others. Hence, sphingoid bases and fatty acids have different antibacterial activities and may have potential for prophylactic or therapeutic intervention in infection. PMID:22155833

Fischer, Carol L; Drake, David R; Dawson, Deborah V; Blanchette, Derek R; Brogden, Kim A; Wertz, Philip W

2012-03-01

5

In vitro activity of XF-73, a novel antibacterial agent, against antibiotic-sensitive and -resistant Gram-positive and Gram-negative bacterial species  

Microsoft Academic Search

The antibacterial activity of XF-73, a dicationic porphyrin drug, was investigated against a range of Gram-positive and Gram-negative bacteria with known antibiotic resistance profiles, including resistance to cell wall synthesis, protein synthesis, and DNA and RNA synthesis inhibitors as well as cell membrane-active antibiotics. Antibiotic-sensitive strains for each of the bacterial species tested were also included for comparison purposes. XF-73

David J. Farrell; Marion Robbins; William Rhys-Williams; William G. Love

2010-01-01

6

Antibacterial activity of silver-doped hydroxyapatite nanoparticles against gram-positive and gram-negative bacteria  

PubMed Central

Ag-doped nanocrystalline hydroxyapatite nanoparticles (Ag:HAp-NPs) (Ca10-xAgx(PO4)6(OH)2, xAg?=?0.05, 0.2, and 0.3) with antibacterial properties are of great interest in the development of new products. Coprecipitation method is a promising route for obtaining nanocrystalline Ag:HAp with antibacterial properties. X-ray diffraction identified HAp as an unique crystalline phase in each sample. The calculated lattice constants of a?=?b?=?9.435 Å, c?=?6.876 Å for xAg?=?0.05, a?=?b?=?9.443 Å, c?=?6.875 Å for xAg?=?0.2, and a?=?b?=?9.445 Å, c?=?6.877 Å for xAg?=?0.3 are in good agreement with the standard of a?=?b?=?9.418 Å, c?=?6.884 Å (space group P63/m). The Fourier transform infrared and Raman spectra of the sintered HAp show the absorption bands characteristic to hydroxyapatite. The Ag:HAp nanoparticles are evaluated for their antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, Providencia stuartii, Citrobacter freundii and Serratia marcescens. The results showed that the antibacterial activity of these materials, regardless of the sample types, was greatest against S. aureus, K. pneumoniae, P. stuartii, and C. freundii. The results of qualitative antibacterial tests revealed that the tested Ag:HAp-NPs had an important inhibitory activity on P. stuartii and C. freundii. The absorbance values measured at 490 nm of the P. stuartii and C. freundii in the presence of Ag:HAp-NPs decreased compared with those of organic solvent used (DMSO) for all the samples (xAg?=?0.05, 0.2, and 0.3). Antibacterial activity increased with the increase of xAg in the samples. The Ag:HAp-NP concentration had little influence on the bacterial growth (P. stuartii).

2012-01-01

7

Antibacterial activity of Acinetobacter baumannii phage ?AB2 endolysin (LysAB2) against both gram-positive and gram-negative bacteria.  

PubMed

To investigate the nature and origin of the antibacterial activity of the lytic phage ?AB2 toward Acinetobacter baumannii, we successfully isolated and characterized a novel phage lysozyme (endolysin) from ?AB2 and named it LysAB2. To analyze antibacterial activity of LysAB2, the complete LysAB2 and two deletion derivatives were constructed, purified and characterized. Zymographic assays showed that only the intact LysAB2 could lyse the peptidoglycan of A. baumannii and the Staphylococcus aureus cell wall. Antibacterial analysis also showed that only the intact LysAB2 retained the complete bactericidal activity. When applied exogenously, LysAB2 exhibited a broad bacteriolytic activity against a number of Gram-negative and Gram-positive bacteria. Thermostability assays indicated that LysAB2 was stable at 20?40 °C. Its optimal pH was 6.0, and it was active from pH 4 to 8. Scanning electron microscopy revealed that exposure to 500 ?gml(-1) LysAB2 for up to 60 min caused a remarkable modification of the cell shape of the bacteria. Treating bacteria with LysAB2 clearly enhanced permeation of the bacterial cytoplasmic membrane. These results indicate that LysAB2 is an effective lysozyme against bacteria, and they suggest that it is a good candidate for a therapeutic/disinfectant agent to control nosocomial infections caused by multiple drug-resistant bacteria. PMID:21264466

Lai, Meng-Jiun; Lin, Nien-Tsung; Hu, Anren; Soo, Po-Chi; Chen, Li-Kuang; Chen, Long-Hui; Chang, Kai-Chih

2011-04-01

8

Enhancement of Antibacterial Activity of Capped Silver Nanoparticles in Combination with Antibiotics, on Model Gram-Negative and Gram-Positive Bacteria  

PubMed Central

The nanoparticles used in this study were prepared from AgNO3 using NaBH4 in the presence of capping agents such as citrate, sodium dodecyl sulfate, and polyvinylpyrrolidone. The formed nanoparticles were characterized with UV-Vis, TEM, and XRD. The generation of silver nanoparticles was confirmed from the appearance of yellow colour and an absorption maximum between 399 and 404?nm. The produced nanoparticles were found to be spherical in shape and polydisperse. For citrate, SDS, and PVP capped nanoparticles, the average particle sizes were 38.3 ± 13.5, 19.3 ± 6.0, and 16.0 ± 4.8?nm, respectively. The crystallinity of the nanoparticles in FCC structure is confirmed from the SAED and XRD patterns. Also, the combined antibacterial activity of these differently capped nanoparticles with selected antibiotics (streptomycin, ampicillin, and tetracycline) was evaluated on model Gram-negative and Gram-positive bacteria, employing disc diffusion assay. The activity of the tested antibiotics was enhanced in combination with all the stabilized nanoparticles, against both the Gram classes of bacteria. The combined effects of silver nanoparticles and antibiotics were more prominent with PVP capped nanoparticles as compared to citrate and SDS capped ones. The results of this study demonstrate potential therapeutic applications of silver nanoparticles in combination with antibiotics.

Kora, Aruna Jyothi; Rastogi, Lori

2013-01-01

9

In Vitro Evaluation of the Antibacterial Activity of Three Different Central Venous Catheters Against Gram-Positive Bacteria  

Microsoft Academic Search

.   The aim of this study was to evaluate the activity of three different catheters against Staphylococcus aureus ATCC 29213 and the slime-producing Staphylococcus epidermidis ATCC 35984 (RP62A). Three central venous catheters were evaluated: one impregnated with silver sulfadiazine–chlorhexidine,\\u000a one to which minocycline\\/rifampin is bonded and a novel one into which silver, platinum and carbon are incorporated. A nonantiseptic\\u000a catheter

K. Yorganci; C. Krepel; J. Weigelt; C. Edmiston

2002-01-01

10

Antibacterial inhibitors of Gram-positive thymidylate kinase: structure-activity relationships and chiral preference of a new hydrophobic binding region.  

PubMed

Thymidylate kinase (TMK), an essential enzyme in bacterial DNA biosynthesis, is an attractive therapeutic target for the development of novel antibacterial agents, and we continue to explore TMK inhibitors with improved potency, protein binding, and pharmacokinetic potential. A structure-guided design approach was employed to exploit a previously unexplored region in Staphylococcus aureus TMK via novel interactions. These efforts produced compound 39, with 3 nM IC50 against S. aureus TMK and 2 ?g/mL MIC against methicillin-resistant S. aureus (MRSA). This compound exhibits a striking inverted chiral preference for binding relative to earlier compounds and also has improved physical properties and pharmacokinetics over previously published compounds. An example of this new series was efficacious in a murine S. aureus infection model, suggesting that compounds like 39 are options for further work toward a new Gram-positive antibiotic by maintaining a balance of microbiological potency, low clearance, and low protein binding that can result in lower efficacious doses. PMID:24828090

Kawatkar, Sameer P; Keating, Thomas A; Olivier, Nelson B; Breen, John N; Green, Oluyinka M; Guler, Satenig Y; Hentemann, Martin F; Loch, James T; McKenzie, Andrew R; Newman, Joseph V; Otterson, Linda G; Martínez-Botella, Gabriel

2014-06-12

11

Salusin-?, an Antimicrobially Active Peptide against Gram-Positive Bacteria.  

PubMed

Salusin-? has been detected in numerous mammalian tissues and has been shown to have various effects on the cardiovascular system. In this study, we showed that salusin-? exhibited potent antibacterial activity against Gram-positive microorganisms such as Bacillus subtilis NBRC 3513, Bacillus megaterium ATCC 19213, Staphylococcus aureus NBRC 12732, and Staphylococcus epidermidis NBRC 12933. A cytoplasmic membrane-depolarizing assay using the DiSC3(5) dye revealed that the addition of 4?nmol/mL of salusin-? caused the leakage of fluorescence dye from Staphylococcus aureus NBRC 12732. The antimicrobial potency and circular dichroism (CD) spectroscopy of five analogs related to salusin-? were examined to determine structure-function relationships in its N- and C-terminal regions. The results obtained suggest that the N-terminal sequences of the salusin-? molecule are important for the expression of the potent antimicrobial activity of this peptide. A profile corresponding to that of the ?-helix conformation was observed in the salusin-? solution. PMID:24881665

Kimura, Masahiro; Shindo, Mitsuno; Moriizumi, Toshiyuki; Tagawa, Noriko; Fujinami, Aya; Kato, Ikuo; Uchida, Yoshiki

2014-01-01

12

Discriminatory antibacterial effects of calix[n]arene capped silver nanoparticles with regard to gram positive and gram negative bacteria.  

PubMed

Silver nanoparticles capped with nine different sulphonated calix[n]arenes were tested for their anti-bacterial effects against B. subtilis and E. coli at an apparent concentration of 100 nM in calix[n]arene. The results show the para-sulphonato-calix[n]arenes are active against Gram positive bacteria and the derivatives having sulphonate groups at both para and alkyl terminal positions are active against Gram negative bacteria. The calix[6]arene derivative with only O-alkyl sulphonate groups shows bactericidal activity. PMID:23831853

Boudebbouze, Samira; Coleman, Anthony W; Tauran, Yannick; Mkaouar, Hela; Perret, Florent; Garnier, Alexandrine; Brioude, Arnaud; Kim, Beomjoon; Maguin, Emmanuelle; Rhimi, Moez

2013-08-18

13

Bioengineered nisin A derivatives with enhanced activity against both Gram positive and Gram negative pathogens.  

PubMed

Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G), with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E) with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria. PMID:23056510

Field, Des; Begley, Maire; O'Connor, Paula M; Daly, Karen M; Hugenholtz, Floor; Cotter, Paul D; Hill, Colin; Ross, R Paul

2012-01-01

14

Bioengineered Nisin A Derivatives with Enhanced Activity against Both Gram Positive and Gram Negative Pathogens  

PubMed Central

Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G), with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E) with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria.

Field, Des; Begley, Maire; O'Connor, Paula M.; Daly, Karen M.; Hugenholtz, Floor; Cotter, Paul D.; Hill, Colin; Ross, R. Paul

2012-01-01

15

In Vitro Activities of Linezolid against Important Gram-Positive Bacterial Pathogens Including Vancomycin-Resistant Enterococci  

Microsoft Academic Search

The emergence of resistance in gram-positive bacteria has necessitated a search for new antimicrobial agents. Linezolid is an oxazolidinone, a new class of antibacterial agents with enhanced activity against pathogens. We compared the activity of linezolid to those of other antimicrobial agents against 3,945 clinical isolates. Linezolid demonstrated potent activity against all isolates tested. For all vancomycin-susceptible enterococci, staphylococci, and

GARY A. NOSKIN; FARIDA SIDDIQUI; VALENTINA STOSOR; DONNA HACEK; LANCE R. PETERSON

1999-01-01

16

Mannopeptimycins, a novel class of glycopeptide antibiotics active against gram-positive bacteria.  

PubMed

Mannopeptimycins alpha-epsilon, novel glycopeptides with activity against methicillin-resistant staphylococci and vancomycin-resistant enterococci, are purified from the fermentation broth of a strain of Streptomyces hygroscopicus, LL-AC98, and their structures characterized using spectroscopic analyses and chemical methods. The SAR data of the natural and synthetic esters demonstrate that the presence of hydrophobic groups near the terminal mannosyl moiety is critical for antibacterial potency. Scalable syntheses of 4,6-cyclic acetals and ketals on this moiety are used to produce significant quantities of the respective mannopeptimycin derivatives. These acetal and ketal derivatives exhibit potent activities against susceptible and resistant Gram-positive bacteria in both in vitro and in vivo experiments, comparable with or exceeding the activity of vancomycin. Studies on the mechanism of action suggest that the mannopeptimycins interfere with the late stages of bacterial cell wall biosynthesis. It is believed that these antibiotics inhibit the transglycosylation by binding to the transglycosylase substrate, lipid II. PMID:15702316

He, Haiyin

2005-06-01

17

Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study  

PubMed Central

Background Nanomaterials have unique properties compared to their bulk counterparts. For this reason, nanotechnology has attracted a great deal of attention from the scientific community. Metal oxide nanomaterials like ZnO and CuO have been used industrially for several purposes, including cosmetics, paints, plastics, and textiles. A common feature that these nanoparticles exhibit is their antimicrobial behavior against pathogenic bacteria. In this report, we demonstrate the antimicrobial activity of ZnO, CuO, and Fe2O3 nanoparticles against Gram-positive and Gram-negative bacteria. Methods and results Nanosized particles of three metal oxides (ZnO, CuO, and Fe2O3) were synthesized by a sol–gel combustion route and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy techniques. X-ray diffraction results confirmed the single-phase formation of all three nanomaterials. The particle sizes were observed to be 18, 22, and 28 nm for ZnO, CuO, and Fe2O3, respectively. We used these nanomaterials to evaluate their antibacterial activity against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. Conclusion Among the three metal oxide nanomaterials, ZnO showed greatest antimicrobial activity against both Gram-positive and Gram-negative bacteria used in this study. It was observed that ZnO nanoparticles have excellent bactericidal potential, while Fe2O3 nanoparticles exhibited the least bactericidal activity. The order of antibacterial activity was demonstrated to be the following: ZnO > CuO > Fe2O3.

Azam, Ameer; Ahmed, Arham S; Oves, Mohammad; Khan, Mohammad S; Habib, Sami S; Memic, Adnan

2012-01-01

18

Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajava L.) on Two Gram-Negative and Gram-Positive Bacteria  

PubMed Central

Aim. To determine the antimicrobial potential of guava (Psidium guajava) leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water). The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50??L leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3?mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0?mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties.

Biswas, Bipul; Rogers, Kimberly; McLaughlin, Fredrick; Yadav, Anand

2013-01-01

19

Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajava L.) on Two Gram-Negative and Gram-Positive Bacteria.  

PubMed

Aim. To determine the antimicrobial potential of guava (Psidium guajava) leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water). The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50? ? L leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3?mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0?mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties. PMID:24223039

Biswas, Bipul; Rogers, Kimberly; McLaughlin, Fredrick; Daniels, Dwayne; Yadav, Anand

2013-01-01

20

Comparative in vitro activity of levofloxacin and ofloxacin against Gram-positive bacteria  

Microsoft Academic Search

The in vitro activity of levofloxacin against 506 Gram-positive bacteria was compared with those of D(?)-ofloxacin, ofloxacin, ciprofloxacin, and sparfloxacin. Levofloxacin was generally twice as active as ofloxacin against these organisms (range, 0–3 twofold dilutions). Sparfloxacin appeared to have the greatest activity overall, but for several groups of organisms minimum inhibitory concentrations (MIC90s) of this com pound were within one

George M. Eliopoulos; Christine B. Wennersten; Robert C. Moellering

1996-01-01

21

Drosophila Toll is activated by Gram-positive bacteria through a circulating peptidoglycan recognition protein  

Microsoft Academic Search

Microbial infection activates two distinct intracellular signalling cascades in the immune-responsive fat body of Drosophila. Gram-positive bacteria and fungi predominantly induce the Toll signalling pathway, whereas Gram-negative bacteria activate the Imd pathway. Loss-of-function mutants in either pathway reduce the resistance to corresponding infections. Genetic screens have identified a range of genes involved in these intracellular signalling cascades, but how they

Tatiana Michel; Jean-Marc Reichhart; Jules A. Hoffmann; Julien Royet

2001-01-01

22

Antibacterial effect (in vitro) of Moringa oleifera and Annona muricata against Gram positive and Gram negative bacteria.  

PubMed

Antibacterial effects of aqueous and ethanolic extracts of seeds of moringa (Moringa oleifera) and pods of soursop (Annona muricata) in the concentration of 1:5 and 1:10 in volumes 50, 100, 150 and 200 microL were examined against Staphylococcus aureus, Vibrio cholerae, Escherichia coli (isolated from the organism and the aquatic environment) and Salmonella Enteritidis. Antibacterial activity (inhibition halo > 13 mm) against S. aureus, V. cholerae and E. coli isolated from the whiteleg shrimp, Litopenaeus vannmaei, was detected in aqueous and ethanolic extracts of moringa. E. coli isolated from tilapiafish, Oreochromis niloticus, was sensitive to the ethanolic extract of moringa. The aqueous extracts of soursop showed an antibacterial effect against S. aureus and V. cholerae, but the antibacterial activity by the ethanol extracts of this plant was not demonstrated. PMID:20602021

Viera, Gustavo Hitzschky Fernandes; Mourão, Jozeanne Alves; Angelo, Angela Maria; Costa, Renata Albuquerque; Vieira, Regine Helena Silva dos Fernandes

2010-01-01

23

Filamentous Phage Active on the Gram-Positive Bacterium Propionibacterium freudenreichii  

PubMed Central

We present the first description of a single-stranded DNA filamentous phage able to replicate in a gram-positive bacterium. Phage B5 infects Propionibacterium freudenreichii and has a genome consisting of 5,806 bases coding for 10 putative open reading frames. The organization of the genome is very similar to the organization of the genomes of filamentous phages active on gram-negative bacteria. The putative coat protein exhibits homology with the coat proteins of phages PH75 and Pf3 active on Thermus thermophilus and Pseudomonas aeruginosa, respectively. B5 is, therefore, evolutionarily related to the filamentous phages active on gram-negative bacteria.

Chopin, Marie-Christine; Rouault, Annette; Ehrlich, S. Dusko; Gautier, Michel

2002-01-01

24

Comparative in vitro activity profile of oritavancin against recent gram-positive clinical isolates.  

PubMed

Oritavancin activity was tested against 15,764 gram-positive isolates collected from 246 hospital centers in 25 countries between 2005 and 2008. Organisms were Staphylococcus aureus (n = 9,075), coagulase-negative staphylococci (n = 1,664), Enterococcus faecalis (n = 1,738), Enterococcus faecium (n = 819), Streptococcus pyogenes (n = 959), Streptococcus agalactiae (n = 415), group C, G, and F streptococci (n = 84), and Streptococcus pneumoniae (n = 1,010). Among the evaluated staphylococci, 56.7% were resistant to oxacillin. The vancomycin resistance rate among enterococci was 21.2%. Penicillin-resistant and -intermediate rates were 14.7% and 21.4%, respectively, among S. pneumoniae isolates. Among nonpneumococcal streptococci, 18.5% were nonsusceptible to erythromycin. Oritavancin showed substantial in vitro activity against all organisms tested, regardless of resistance profile. The maximum oritavancin MIC against all staphylococci tested (n = 10,739) was 4 microg/ml; the MIC(90) against S. aureus was 0.12 microg/ml. Against E. faecalis and E. faecium, oritavancin MIC(90)s were 0.06 and 0.12, respectively. Oritavancin was active against glycopeptide-resistant enterococci, including VanA strains (n = 486), with MIC(90)s of 0.25 and 1 microg/ml against VanA E. faecium and E. faecalis, respectively. Oritavancin showed potent activity against streptococci (n = 2,468); MIC(90)s for the different streptococcal species were between 0.008 and 1 microg/ml. These data are consistent with previous studies with respect to resistance rates of gram-positive isolates and demonstrate the spectrum and in vitro activity of oritavancin against a wide variety of contemporary gram-positive pathogens, regardless of resistance to currently used drugs. The data provide a foundation for interpreting oritavancin activity and potential changes in susceptibility over time once oritavancin enters into clinical use. PMID:19738026

Arhin, Francis F; Draghi, Deborah C; Pillar, Chris M; Parr, Thomas R; Moeck, Gregory; Sahm, Daniel F

2009-11-01

25

Comparative In Vitro Activity Profile of Oritavancin against Recent Gram-Positive Clinical Isolates?  

PubMed Central

Oritavancin activity was tested against 15,764 gram-positive isolates collected from 246 hospital centers in 25 countries between 2005 and 2008. Organisms were Staphylococcus aureus (n = 9,075), coagulase-negative staphylococci (n = 1,664), Enterococcus faecalis (n = 1,738), Enterococcus faecium (n = 819), Streptococcus pyogenes (n = 959), Streptococcus agalactiae (n = 415), group C, G, and F streptococci (n = 84), and Streptococcus pneumoniae (n = 1,010). Among the evaluated staphylococci, 56.7% were resistant to oxacillin. The vancomycin resistance rate among enterococci was 21.2%. Penicillin-resistant and -intermediate rates were 14.7% and 21.4%, respectively, among S. pneumoniae isolates. Among nonpneumococcal streptococci, 18.5% were nonsusceptible to erythromycin. Oritavancin showed substantial in vitro activity against all organisms tested, regardless of resistance profile. The maximum oritavancin MIC against all staphylococci tested (n = 10,739) was 4 ?g/ml; the MIC90 against S. aureus was 0.12 ?g/ml. Against E. faecalis and E. faecium, oritavancin MIC90s were 0.06 and 0.12, respectively. Oritavancin was active against glycopeptide-resistant enterococci, including VanA strains (n = 486), with MIC90s of 0.25 and 1 ?g/ml against VanA E. faecium and E. faecalis, respectively. Oritavancin showed potent activity against streptococci (n = 2,468); MIC90s for the different streptococcal species were between 0.008 and 1 ?g/ml. These data are consistent with previous studies with respect to resistance rates of gram-positive isolates and demonstrate the spectrum and in vitro activity of oritavancin against a wide variety of contemporary gram-positive pathogens, regardless of resistance to currently used drugs. The data provide a foundation for interpreting oritavancin activity and potential changes in susceptibility over time once oritavancin enters into clinical use.

Arhin, Francis F.; Draghi, Deborah C.; Pillar, Chris M.; Parr, Thomas R.; Moeck, Gregory; Sahm, Daniel F.

2009-01-01

26

Structure-Activity Relationships of 3,3?-Phenylmethylene-bis-4-hydroxycoumarins: Selective and Potent Inhibitors of Gram-Positive Bacteria  

PubMed Central

Dicoumarols and coumarin derivatives have shown a variety of pharmaceutical activities and have been found to be potent inhibitor for the NAD(P)H-dependent flavoproteins. In this report, dicoumarol and its derivatives containing the substituted benzene ring at the methylenebis position were synthesized and evaluated for their antibacterial activity against gram-positive bacteria: Staphylococcus aureus and Bacillus subtilis, and gram-negative bacteria: Escherichia coli and Klebsiella sp. The results showed that the synthesized dicoumarols affect cell growth but are selective against gram-positive over gram-negative bacterial cells. However, for most derivatives, the substitution of steric bulky benzene group on the methylenebis position appears to decrease in the efficacy of antibacterial effect. This finding is roughly described by the predicted poorer docked structure of the derivatives to a homology model of S. aureus flavoprotein. 3D-QSAR study highlighted structural features around the substituted benzene ring of dicoumarols as the antibacterial activity. CoMFA and CoMSIA contour maps support the idea that steric repulsion at the para position could diminish the antibacterial activity. The results of this study provide a better understanding of the molecular basis for the antibacterial activity of dicoumarols.

Chavasiri, Warinthorn

2013-01-01

27

Anti-bacterial performance of azithromycin nanoparticles as colloidal drug delivery system against different gram-negative and gram-positive bacteria  

PubMed Central

Purpose: Azithromycin (AZI) is a new macrolide antibiotic with a better activity against intracellular gram negative bacteria in comparison with Erythromycin. The purpose of this research was to prepare AZI nanoparticles (NPs) using PLGA polymer and to compare the effectiveness of prepared nanoparticles with untreated AZI solution. Methods: AZI NPs were prepared by Modified Quasi-Emulsion Solvent Diffusion method. The antibacterial activities of prepared NPs in comparison with AZI solution were assayed against indicator bacteria of Escherichia coli (PTCC 1330), Haemophilus influenzae (PTCC 1623) and Streptococcus pneumoniae (PTCC 1240) using agar well diffusion. Inhibition zone diameters (IZD) of nano-formulation were compared to the corresponding untreated AZI. Mean Inhibitory Concentration (MIC) values of AZI were also determined using serial dilution method in nutrient broth medium. Results: Mean IZD of nano-formulations for all indicator bacteria were significantly higher than that of untreated AZI (P<0.01). The enhanced antibacterial efficacy was more dominant in the gram positive species. The MIC values of NPs against the tested bacteria were reduced 8 times in comparison to those of untreated AZI. Conclusion: These results indicated an improved potency of AZI NPs which could be attributed to the modified surface characteristics as well as increased drug adsorption and uptake.

Azhdarzadeh, Morteza; Lotfipour, Farzaneh; Zakeri-Milani, Parvin; Mohammadi, Ghobad; Valizadeh, Hadi

2012-01-01

28

Activation and manipulation of host responses by a Gram-positive bacterium.  

PubMed

The interaction between tomato plants and Clavibacter michiganensis subsp. michiganensis (Cmm) represents a model pathosystem to study the interplay between the virulence determinants of a Gram-positive bacterium and the attempt of a crop plant to counteract pathogen invasion. To investigate plant responses activated during this compatible interaction, we recently analyzed gene expression profiles of tomato stems infected with Cmm. This analysis revealed activation of basal defense responses that are typically observed upon plant perception of pathogen-associated molecular patterns. In addition, Cmm infection upregulated the expression of host genes related to ethylene synthesis and response. Further analysis of tomato plants impaired in ethylene perception and production demonstrated an important role for ethylene in the development of disease symptoms. Here we discuss possible molecular strategies used by the plant to recognize Cmm infection and possible mechanisms employed by the pathogen to interfere with the activation of plant defense responses and promote disease. PMID:19704516

Balaji, Vasudevan; Sessa, Guido

2008-10-01

29

Antioxidant activity via DPPH, gram-positive and gram-negative antimicrobial potential in edible mushrooms.  

PubMed

Edible mushrooms (EMs) are nutritionally rich source of proteins and essential amino acids. In the present study, the antioxidant activity via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and antimicrobial potential in EMs (Pleurotus ostreatus, Morchella esculenta, P. ostreatus (Black), P. ostreatus (Yellow) and Pleurotus sajor-caju) were investigated. The DPPH radical scavenging activity revealed that the significantly higher activity (66.47%) was observed in Morchella esculenta at a maximum concentration. Similarly, the dose-dependent concentrations (200, 400, 600, 800 and 1000 µg) were also used for other four EMs. Pleurotus ostreatus exhibited 36.13% activity, P. ostreatus (Black (B)) exhibited 30.64%, P. ostreatus (Yellow (Y)) exhibited 40.75% and Pleurotus sajor-caju exhibited 47.39% activity at higher concentrations. Furthermore, the antimicrobial potential were investigated for its toxicity against gram-negative bacterial strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Klebsiella pneumonia, Erwinia carotovora and Agrobacterium tumifaciens), gram-positive bacterial strains (Bacillus subtilis, Bacillus atrophaeus and Staphylococcus aureus) and a fungal strain (Candida albicans) in comparison with standard antibiotics. Antimicrobial screening revealed that the ethanol extract of P. ostreatus was active against all microorganism tested except E. coli. Maximum zone of inhibition (13 mm) was observed against fungus and A. tumifaciens. P. sajor-caju showed best activities (12.5 mm) against B. subtilis, B. atrophaeus and K. pneumonia. P. ostreatus (Y) showed best activities against P. aeroginosa (21.83 mm), B. atrophaeus (20 mm) and C. albicans (21 mm). P. ostreatus (B) exhibited best activities against C. albicans (16 mm) and slightly lower activities against all other microbes except S. typhi. M. esculenta possess maximum activities in terms of inhibition zone against all microorganisms tested except S. typhi. PMID:23095488

Ahmad, Nisar; Mahmood, Fazal; Akbar Khalil, Shahid; Zamir, Roshan; Fazal, Hina; Abbasi, Bilal Haider

2012-10-24

30

In vitro activity of daptomycin against Gram-positive cocci: the first multicentre study in Greece.  

PubMed

A total of 10420 Gram-positive cocci (including staphylococci, enterococci and various groups of streptococci) collected from clinically significant specimens in ten Greek hospitals during 2006--2007 were tested for their susceptibility to daptomycin. The minimum inhibitory concentration (MIC) was determined by the broth microdilution method. Daptomycin demonstrated very high activity against Enterococcus faecalis (MIC at which 50% of the isolates were inhibited (MIC50) = 1mg/L and MIC at which 90% of the isolates were inhibited (MIC90) = 1.36 mg/L), Enterococcus faecium (MIC50 = 1.36 mg/L and MIC90 = 1.90 mg/L), Streptococcus pyogenes (MIC50 = 0.12 mg/L and MIC90 = 0.50mg/L), Streptococcus agalactiae (MIC50 = 0.09 mg/L and MIC90 = 0.12 mg/L), Streptococcus pneumoniae (MIC50 = 0.24 mg/L and MIC90 = 0.5 mg/L) and viridans group streptococci (MIC50 = 0.50 mg/L and MIC90 = 0.89 mg/L). Resistance to linezolid and vancomycin for enterococci and to penicillin for streptococci appears to be independent of reduced susceptibility to daptomycin. On the other hand, daptomycin was also active against meticillin-resistant Staphylococcus aureus (MIC50 = 0.44 mg/L and MIC90 = 0.78 mg/L) and meticillin-resistant coagulase-negative staphylococci (MIC50 = 0.24 mg/L and MIC90 = 0.44 mg/L); however, 0.9% of the staphylococci tested had an MIC > 1mg/L, which is the Clinical and Laboratory Standards Institute breakpoint proposed for susceptibility. For all tested organism groups, resistance to daptomycin was not associated with glycopeptide resistance. PMID:18774268

Malli, E; Spiliopoulou, I; Kolonitsiou, F; Klapsa, D; Giannitsioti, E; Pantelidi, K; Pratti, A; Panopoulou, M; Grapsa, S; Alepopoulou, E; Neonakis, I; Frantzidou, F; Alexiou-Daniel, S; Bakola, D; Koutsia-Carouzou, C; Malamou-Lada, H; Zerva, L; Vlahaki, E; Kartali-Ktenidou, S; Anastassiou, E D; Petinaki, E

2008-12-01

31

In Vitro Activities of a New Lipopeptide, HMR 1043, against Susceptible and Resistant Gram-Positive Isolates  

Microsoft Academic Search

The purpose of this study was to compare the activity of HMR 1043 with those of daptomycin and teicoplanin against gram-positive isolates. Susceptibility tests were performed for 52 strains, 26 parental strains, including staphylococcal, streptococcal, enterococcal, and listerial strains, and 26 HMR 1043-resistant mutants obtained from parental strains by using the Szybalski method. Agar dilution and disk diffusion susceptibility tests

Pascale Bemer; Marie-Emmanuelle Juvin; Andre Bryskier; Henri Drugeon

2003-01-01

32

Comparative Surveillance Study of Telavancin Activity against Recently Collected Gram-Positive Clinical Isolates from across the United States  

Microsoft Academic Search

Telavancin is an investigational, rapidly bactericidal lipoglycopeptide antibiotic that is being developed to treat serious infections caused by gram-positive bacteria. A baseline prospective surveillance study was conducted to assess telavancin activity, in comparison with other agents, against contemporary clinical isolates collected from 2004 to 2005 from across the United States. Nearly 4,000 isolates were collected, including staphylococci, enterococci, and streptococci

Deborah C. Draghi; Bret M. Benton; Kevin M. Krause; Clyde Thornsberry; Chris Pillar; Daniel F. Sahm

2008-01-01

33

In Vitro Activity of Ozenoxacin against Quinolone-Susceptible and Quinolone-Resistant Gram-Positive Bacteria  

PubMed Central

In vitro activity of ozenoxacin, a novel nonfluorinated topical (L. D. Saravolatz and J. Leggett, Clin. Infect. Dis. 37:1210–1215, 2003) quinolone, was compared with the activities of other quinolones against well-characterized quinolone-susceptible and quinolone-resistant Gram-positive bacteria. Ozenoxacin was 3-fold to 321-fold more active than other quinolones. Ozenoxacin could represent a first-in-class nonfluorinated quinolone for the topical treatment of a broad range of dermatological infections.

Lopez, Y.; Tato, M.; Espinal, P.; Garcia-Alonso, F.; Gargallo-Viola, D.; Canton, R.

2013-01-01

34

Biosynthetic Pathway for Mannopeptimycins, Lipoglycopeptide Antibiotics Active against Drug-Resistant Gram-Positive Pathogens  

PubMed Central

The mannopeptimycins are a novel class of lipoglycopeptide antibiotics active against multidrug-resistant pathogens with potential as clinically useful antibacterials. This report is the first to describe the biosynthesis of this novel class of mannosylated lipoglycopeptides. Included here are the cloning, sequencing, annotation, and manipulation of the mannopeptimycin biosynthetic gene cluster from Streptomyces hygroscopicus NRRL 30439. Encoded by genes within the mannopeptimycin biosynthetic gene cluster are enzymes responsible for the generation of the hexapeptide core (nonribosomal peptide synthetases [NRPS]) and tailoring reactions (mannosylation, isovalerylation, hydroxylation, and methylation). The NRPS system is noncanonical in that it has six modules utilizing only five amino acid-specific adenylation domains and it lacks a prototypical NRPS macrocyclizing thioesterase domain. Analysis of the mannopeptimycin gene cluster and its engineering has elucidated the mannopeptimycin biosynthetic pathway and provides the framework to make new and improved mannopeptimycins biosynthetically.

Magarvey, Nathan A.; Haltli, Brad; He, Min; Greenstein, Michael; Hucul, John A.

2006-01-01

35

Biosynthetic pathway for mannopeptimycins, lipoglycopeptide antibiotics active against drug-resistant gram-positive pathogens.  

PubMed

The mannopeptimycins are a novel class of lipoglycopeptide antibiotics active against multidrug-resistant pathogens with potential as clinically useful antibacterials. This report is the first to describe the biosynthesis of this novel class of mannosylated lipoglycopeptides. Included here are the cloning, sequencing, annotation, and manipulation of the mannopeptimycin biosynthetic gene cluster from Streptomyces hygroscopicus NRRL 30439. Encoded by genes within the mannopeptimycin biosynthetic gene cluster are enzymes responsible for the generation of the hexapeptide core (nonribosomal peptide synthetases [NRPS]) and tailoring reactions (mannosylation, isovalerylation, hydroxylation, and methylation). The NRPS system is noncanonical in that it has six modules utilizing only five amino acid-specific adenylation domains and it lacks a prototypical NRPS macrocyclizing thioesterase domain. Analysis of the mannopeptimycin gene cluster and its engineering has elucidated the mannopeptimycin biosynthetic pathway and provides the framework to make new and improved mannopeptimycins biosynthetically. PMID:16723579

Magarvey, Nathan A; Haltli, Brad; He, Min; Greenstein, Michael; Hucul, John A

2006-06-01

36

In vitro activities of a new lipopeptide, HMR 1043, against susceptible and resistant gram-positive isolates.  

PubMed

The purpose of this study was to compare the activity of HMR 1043 with those of daptomycin and teicoplanin against gram-positive isolates. Susceptibility tests were performed for 52 strains, 26 parental strains, including staphylococcal, streptococcal, enterococcal, and listerial strains, and 26 HMR 1043-resistant mutants obtained from parental strains by using the Szybalski method. Agar dilution and disk diffusion susceptibility tests were performed by the procedures outlined by the NCCLS. HMR 1043 demonstrated good activity against susceptible and resistant gram-positive bacteria. The activity of HMR 1043 in vitro was less influenced by the presence of calcium ions than that of daptomycin. Susceptibility test breakpoints were not defined because of the poor correlation coefficients obtained with the different disks tested. PMID:12937020

Bemer, Pascale; Juvin, Marie-Emmanuelle; Bryskier, Andre; Drugeon, Henri

2003-09-01

37

In Vitro Activities of a New Lipopeptide, HMR 1043, against Susceptible and Resistant Gram-Positive Isolates  

PubMed Central

The purpose of this study was to compare the activity of HMR 1043 with those of daptomycin and teicoplanin against gram-positive isolates. Susceptibility tests were performed for 52 strains, 26 parental strains, including staphylococcal, streptococcal, enterococcal, and listerial strains, and 26 HMR 1043-resistant mutants obtained from parental strains by using the Szybalski method. Agar dilution and disk diffusion susceptibility tests were performed by the procedures outlined by the NCCLS. HMR 1043 demonstrated good activity against susceptible and resistant gram-positive bacteria. The activity of HMR 1043 in vitro was less influenced by the presence of calcium ions than that of daptomycin. Susceptibility test breakpoints were not defined because of the poor correlation coefficients obtained with the different disks tested.

Bemer, Pascale; Juvin, Marie-Emmanuelle; Bryskier, Andre; Drugeon, Henri

2003-01-01

38

Bacteriocins of gram-positive bacteria.  

PubMed Central

In recent years, a group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram-positive pathogenic bacteria. They are ribosomally synthesized peptides of 30 to less than 60 amino acids, with a narrow to wide antibacterial spectrum against gram-positive bacteria; the antibacterial property is heat stable, and a producer strain displays a degree of specific self-protection against its own antibacterial peptide. In many respects, these proteins are quite different from the colicins and other bacteriocins produced by gram-negative bacteria, yet customarily they also are grouped as bacteriocins. Although a large number of these bacteriocins (or bacteriocin-like inhibitory substances) have been reported, only a few have been studied in detail for their mode of action, amino acid sequence, genetic characteristics, and biosynthesis mechanisms. Nevertheless, in general, they appear to be translated as inactive prepeptides containing an N-terminal leader sequence and a C-terminal propeptide component. During posttranslational modifications, the leader peptide is removed. In addition, depending on the particular type, some amino acids in the propeptide components may undergo either dehydration and thioether ring formation to produce lanthionine and beta-methyl lanthionine (as in lantibiotics) or thio ester ring formation to form cystine (as in thiolbiotics). Some of these steps, as well as the translocation of the molecules through the cytoplasmic membrane and producer self-protection against the homologous bacteriocin, are mediated through specific proteins (enzymes). Limited genetic studies have shown that the structural gene for such a bacteriocin and the genes encoding proteins associated with immunity, translocation, and processing are present in a cluster in either a plasmid, the chromosome, or a transposon. Following posttranslational modification and depending on the pH, the molecules may either be released into the environment or remain bound to the cell wall. The antibacterial action against a sensitive cell of a gram-positive strain is produced principally by destabilization of membrane functions. Under certain conditions, gram-negative bacterial cells can also be sensitive to some of these molecules. By application of site-specific mutagenesis, bacteriocin variants which may differ in their antimicrobial spectrum and physicochemical characteristics can be produced. Research activity in this field has grown remarkably but sometimes with an undisciplined regard for conformity in the definition, naming, and categorization of these molecules and their genetic effectors. Some suggestions for improved standardization of nomenclature are offered.

Jack, R W; Tagg, J R; Ray, B

1995-01-01

39

Assessing the interactions of a natural antibacterial clay with model Gram-positive and Gram-negative human pathogens  

NASA Astrophysics Data System (ADS)

The emergence of antibiotic resistant bacteria and increasing accumulations of antibiotics in reclaimed water, drive the quest for new natural antimicrobials. We are studying the antibacterial mechanism(s) of clays that have shown an ability to destroy bacteria or significantly inhibit their growth. One possible mode of action is from soluble transition metal species, particularly reduced Fe, capable of generating deleterious oxygen radical species. Yet another possibility is related to membrane damage as a consequence of physical or electrostatic interaction between clay and bacteria. Both mechanisms could combine to produce cell death. This study addresses a natural antibacterial clay from the NW Amazon basin, South America (AMZ clay). Clay mineralogy is composed of disordered kaolinite (28.9%), halloysite (17.8%) illite (12%) and smectite (16.7%). Mean particle size is 1.6?m and total and specific surface area 278.82 and 51.23 m2/g respectively. The pH of a suspension (200mg/ml) is 4.1 and its Eh is 361mV after 24h of equilibration. The ionic strength of the water in equilibrium with the clay after 24 h. is 6 x10-4M. These conditions, affect the element solubility, speciation, and interactions between clay and bacteria. Standard microbiological methods were used to assess the viability of two model bacteria (Escherichia coli and Bacillus subtilis) after incubation with clay at 37 degC for 24 hrs. A threefold reduction in bacterial viability was observed upon treatment with AMZ clay. We separated the cells from the clay using Nycodenz gradient media and observed the mounts under the TEM and SEM. Results showed several membrane anomalies and structural changes that were not observed in the control cells. Additionally, clay minerals appeared in some places attached to cell walls. Experiments showed that exchanging AMZ clay with KCl caused loss of antibacterial property. Among the exchangeable -and potentially toxic- ions we measured Al+3, Cu+2, Zn+2, Ba+2 and Co+2. Besides being toxic at high concentrations, these species affect the electrophoretic interactions between clay and bacteria surfaces. Additionally, the cation exchange neutralizes the clay surface charge thus modifying further the behavior of particles in suspension. Therefore, we evaluated the clay and bacteria zeta potential (?) as an index for possible electrostatic forces and modeled the total interactions using DLVO theory. We suspended the particles in water equilibrated with clay (leachate). Results show that at pH 4, the ? of clays is -14 mV while it is -3mV for bacteria. The divalent ions and trivalent Aluminum, present in the AMZ leachate, compress the thickness of the double layer (hydration shell) thus decreasing electrostatic repulsion and allowing particles to come closer. The proximity of particles increases the probability of attractive forces to bind clays and cells. In summary, results indicate that a process other than simple chemical transfer from clay to bacteria is operating. The electrostatic attraction and physical proximity may enhance the toxic action of metals and interfere with the membrane properties or processes.

Londono, S. C.; Williams, L. B.

2013-12-01

40

Comparative surveillance study of telavancin activity against recently collected gram-positive clinical isolates from across the United States.  

PubMed

Telavancin is an investigational, rapidly bactericidal lipoglycopeptide antibiotic that is being developed to treat serious infections caused by gram-positive bacteria. A baseline prospective surveillance study was conducted to assess telavancin activity, in comparison with other agents, against contemporary clinical isolates collected from 2004 to 2005 from across the United States. Nearly 4,000 isolates were collected, including staphylococci, enterococci, and streptococci (pneumococci, beta-hemolytic, and viridans). Telavancin had potent activity against Staphylococcus aureus and coagulase-negative staphylococci (MIC range, 0.03 to 1.0 microg/ml), independent of resistance to methicillin or to multiple agents. Telavancin activity was particularly potent against all streptococcal groups (MIC(90)s, 0.03 to 0.12 microg/ml). Telavancin had excellent activity against vancomycin-susceptible enterococci (MIC(90), 1 microg/ml) and was active against VanB strains of vancomycin-resistant enterococci (MIC(90), 2 microg/ml) but less active against VanA strains (MIC(90), 8 to 16 microg/ml). Telavancin also demonstrated activity against vancomycin-intermediate S. aureus and vancomycin-resistant S. aureus strains (MICs, 0.5 microg/ml to 1.0 microg/ml and 1.0 microg/ml to 4.0 microg/ml, respectively). These data may support the efficacy of telavancin for treatment of serious infections with a wide range of gram-positive organisms. PMID:18443115

Draghi, Deborah C; Benton, Bret M; Krause, Kevin M; Thornsberry, Clyde; Pillar, Chris; Sahm, Daniel F

2008-07-01

41

Comparative Surveillance Study of Telavancin Activity against Recently Collected Gram-Positive Clinical Isolates from across the United States ?  

PubMed Central

Telavancin is an investigational, rapidly bactericidal lipoglycopeptide antibiotic that is being developed to treat serious infections caused by gram-positive bacteria. A baseline prospective surveillance study was conducted to assess telavancin activity, in comparison with other agents, against contemporary clinical isolates collected from 2004 to 2005 from across the United States. Nearly 4,000 isolates were collected, including staphylococci, enterococci, and streptococci (pneumococci, beta-hemolytic, and viridans). Telavancin had potent activity against Staphylococcus aureus and coagulase-negative staphylococci (MIC range, 0.03 to 1.0 ?g/ml), independent of resistance to methicillin or to multiple agents. Telavancin activity was particularly potent against all streptococcal groups (MIC90s, 0.03 to 0.12 ?g/ml). Telavancin had excellent activity against vancomycin-susceptible enterococci (MIC90, 1 ?g/ml) and was active against VanB strains of vancomycin-resistant enterococci (MIC90, 2 ?g/ml) but less active against VanA strains (MIC90, 8 to 16 ?g/ml). Telavancin also demonstrated activity against vancomycin-intermediate S. aureus and vancomycin-resistant S. aureus strains (MICs, 0.5 ?g/ml to 1.0 ?g/ml and 1.0 ?g/ml to 4.0 ?g/ml, respectively). These data may support the efficacy of telavancin for treatment of serious infections with a wide range of gram-positive organisms.

Draghi, Deborah C.; Benton, Bret M.; Krause, Kevin M.; Thornsberry, Clyde; Pillar, Chris; Sahm, Daniel F.

2008-01-01

42

A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria  

PubMed Central

The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria.

Quiles-Puchalt, Nuria; Tormo-Mas, Maria Angeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Inigo; Novick, Richard P.; Christie, Gail E.; Penades, Jose R.

2013-01-01

43

A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria.  

PubMed

The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria. PMID:23771138

Quiles-Puchalt, Nuria; Tormo-Más, María Ángeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Iñigo; Novick, Richard P; Christie, Gail E; Penadés, José R

2013-08-01

44

Antibacterial activity of Helichrysum aureonitens (Asteraceae)  

Microsoft Academic Search

The antibacterial activity of extracts from Helichrysum aureonitens was investigated. The dichloromethane extract was active against all five gram positive bacteria tested and the methanol extract was active only against Bacillus cereus, B. pumilus and Micrococcus kristinae, while the water extract had no activity against any of the organisms. None of the extracts inhibited the growth of the five gram

J. J. M. Meyer; A. J. Afolayan

1995-01-01

45

Zulu medicinal plants with antibacterial activity  

Microsoft Academic Search

Aqueous, methanolic and ethyl acetate extracts of 14 plants used in traditional Zulu medicine for treatment of ailments of an infectious nature were screened for antibacterial activity. Most of the activity detected was against Gram-positive bacteria. Tuber bark extracts of Dioscorea sylvatica had activity against Gram-negative Escherichia coli and extracts of Dioscorea dregeana, Cheilanthes viridis and Vernonia colorata were active

Jonathan E. Kelmanson; Anna K. Jäger; Johannes van Staden

2000-01-01

46

In vitro activities of peptide deformylase inhibitors against gram-positive pathogens.  

PubMed

The activities of six peptide deformylase (PDF) inhibitors against 107 respiratory tract pathogens were studied and compared to those of ciprofloxacin and amoxicillin-clavulanate. Against Streptococcus pneumoniae, BB-83698 and BB-83815 were the most active PDF inhibitors (MIC at which 90% of the organisms tested were inhibited [MIC(90)], 0.25 microg/ml). Five of the agents showed similar activity against Moraxella catarrhalis (MIC(90), 0.12 microg/ml). All PDF inhibitors were less active against Haemophilus influenzae; BB-3497 was the most active agent (MIC(90), 2 microg/ml). Five agents were studied against Chlamydia spp. and showed activity similar to that of ciprofloxacin (MIC, 0.5 to 4 microg/ml). This study demonstrates that PDF inhibitors have the potential to be developed for the treatment of respiratory tract infections. PMID:11897602

Wise, R; Andrews, J M; Ashby, J

2002-04-01

47

Daptomycin Activity against Uncommonly Isolated Streptococcal and Other Gram-Positive Species Groups  

PubMed Central

A total of 1,356 clinical isolates were tested against daptomycin by broth microdilution methods. Daptomycin was active against seven groups of viridans group streptococci (MIC50 and MIC90 values ranging from ?0.06 and ?0.06 ?g/ml [Streptococcus bovis and Streptococcus dysgalactiae] to 0.5 and 1 ?g/ml [Streptococcus mitis, Streptococcus oralis, and Streptococcus parasanguinis], respectively), beta-hemolytic streptococci serogroups C, F, and G (MIC50 and MIC90, ?0.06 to 0.25 and 0.12 to 0.25 ?g/ml, respectively), Corynebacterium spp. (MIC50 and MIC90, ?0.06 and 0.12 ?g/ml, respectively), and Micrococcus spp. (MIC50 and MIC90, ?0.06 and 0.25 ?g/ml, respectively). Listeria monocytogenes exhibited higher daptomycin MICs (MIC50 and MIC90, 2 and 4 ?g/ml, respectively) than other tested organisms.

Flamm, Robert K.; Farrell, David J.; Jones, Ronald N.

2013-01-01

48

Daptomycin activity against uncommonly isolated streptococcal and other gram-positive species groups.  

PubMed

A total of 1,356 clinical isolates were tested against daptomycin by broth microdilution methods. Daptomycin was active against seven groups of viridans group streptococci (MIC50 and MIC90 values ranging from ?0.06 and ?0.06 ?g/ml [Streptococcus bovis and Streptococcus dysgalactiae] to 0.5 and 1 ?g/ml [Streptococcus mitis, Streptococcus oralis, and Streptococcus parasanguinis], respectively), beta-hemolytic streptococci serogroups C, F, and G (MIC50 and MIC90, ?0.06 to 0.25 and 0.12 to 0.25 ?g/ml, respectively), Corynebacterium spp. (MIC50 and MIC90, ?0.06 and 0.12 ?g/ml, respectively), and Micrococcus spp. (MIC50 and MIC90, ?0.06 and 0.25 ?g/ml, respectively). Listeria monocytogenes exhibited higher daptomycin MICs (MIC50 and MIC90, 2 and 4 ?g/ml, respectively) than other tested organisms. PMID:24080651

Sader, Helio S; Flamm, Robert K; Farrell, David J; Jones, Ronald N

2013-12-01

49

Screening of Yemeni medicinal plants for antibacterial and cytotoxic activities  

Microsoft Academic Search

Ethanolic extracts of 20 selected plant species used by Yemeni traditional healers to treat infectious diseases were screened for their antibacterial activity against both Gram-positive and Gram-negative bacteria, as well as for cytotoxic activity. Fourteen of the ethanolic extracts showed variable degrees of antibacterial activity. The active ethanolic extracts were partitioned between ethyl acetate and water for a first separation.

N. A. Awadh Ali; W.-D Jülich; C Kusnick; U Lindequist

2001-01-01

50

Antibacterial activity of Helichrysum pedunculatum used in circumcision rites  

Microsoft Academic Search

Antibacterial assays of Helichrysum pedunculatum showed that dichloromethane extracts are active against all the gram positive bacteria tested, as well as two gram negative bacteria, Enterobacter cloacae and Serratia marcescens. A water extract was effective against Staphylococcus aureus and Micrococcus kristinae, while a methanol extract showed no activity against any of the tested organisms. The antibacterial activity of dichloromethane extract

J. J. M. Meyer; F. Dilika

1996-01-01

51

Isolation and Antibacterial Activity of Acylphloroglucinols from Myrtus communis  

PubMed Central

Isolation procedures of two new acylphloroglucinols, myrtucommulone-A and myrtucommulone-B, from Myrtus communis leaves are given. Myrtucommulone-A was highly antibacterial against gram-positive bacteria but was not active against gram negatives. The chemical relation to other acylphloroglucinols and the antibacterial activity of the compounds isolated are discussed.

Rotstein, A.; Lifshitz, A.; Kashman, Y.

1974-01-01

52

Ceftaroline activity tested against uncommonly isolated Gram-positive pathogens: report from the SENTRY Antimicrobial Surveillance Program (2008-2011).  

PubMed

Ceftaroline was tested against 1859 clinically significant Gram-positive organisms from uncommonly isolated species. The organisms (31 species/groups) were collected from 133 medical centres worldwide over a 4-year period (2008-2011). Coagulase-negative staphylococci were generally susceptible to ceftaroline, with MIC50 values (minimum inhibitory concentration required to inhibit 50% of the isolates) of 0.06-0.5mg/L. Ceftaroline was active against Micrococcus spp. [minimum inhibitory concentration required to inhibit 90% of the isolates (MIC90)=0.06 mg/L], but showed more limited potency versus some Corynebacterium spp. and Listeria monocytogenes isolates. Ceftaroline was active against all ?-haemolytic streptococci and viridans group streptococcal species/groups listed, with MIC50 and MIC90 values ranging from ? 0.015 mg/L to 0.03 mg/L and from ? 0.015 mg/L to 0.5mg/L, respectively. Based on these in vitro findings, ceftaroline may have a potential role in the treatment of infections caused by these rarer species as guided by reference MIC test results. PMID:24342717

Sader, Helio S; Jones, Ronald N; Stilwell, Matthew G; Flamm, Robert K

2014-03-01

53

3,5-dioxopyrazolidines, novel inhibitors of UDP-N- acetylenolpyruvylglucosamine reductase (MurB) with activity against gram-positive bacteria.  

PubMed

A series of 3,5-dioxopyrazolidines was identified as novel inhibitors of UDP-N-acetylenolpyruvylglucosamine reductase (MurB). Compounds 1 to 3, which are 1,2-bis(4-chlorophenyl)-3,5-dioxopyrazolidine-4-carboxamides, inhibited Escherichia coli MurB, Staphyloccocus aureus MurB, and E. coli MurA with 50% inhibitory concentrations (IC50s) in the range of 4.1 to 6.8 microM, 4.3 to 10.3 microM, and 6.8 to 29.4 microM, respectively. Compound 4, a C-4-unsubstituted 1,2-bis(3,4-dichlorophenyl)-3,5-dioxopyrazolidine, showed moderate inhibitory activity against E. coli MurB, S. aureus MurB, and E. coli MurC (IC50s, 24.5 to 35 microM). A fluorescence-binding assay indicated tight binding of compound 3 with E. coli MurB, giving a dissociation constant of 260 nM. Structural characterization of E. coli MurB was undertaken, and the crystal structure of a complex with compound 4 was obtained at 2.4 A resolution. The crystal structure indicated the binding of a compound at the active site of MurB and specific interactions with active-site residues and the bound flavin adenine dinucleotide cofactor. Peptidoglycan biosynthesis studies using a strain of Staphylococcus epidermidis revealed reduced peptidoglycan biosynthesis upon incubation with 3,5-dioxopyrazolidines, with IC50s of 0.39 to 11.1 microM. Antibacterial activity was observed for compounds 1 to 3 (MICs, 0.25 to 16 microg/ml) and 4 (MICs, 4 to 8 microg/ml) against gram-positive bacteria including methicillin-resistant S. aureus, vancomycin-resistant Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae. PMID:16436710

Yang, Youjun; Severin, Anatoly; Chopra, Rajiv; Krishnamurthy, Girija; Singh, Guy; Hu, William; Keeney, David; Svenson, Kristine; Petersen, Peter J; Labthavikul, Pornpen; Shlaes, David M; Rasmussen, Beth A; Failli, Amedeo A; Shumsky, Jay S; Kutterer, Kristina M K; Gilbert, Adam; Mansour, Tarek S

2006-02-01

54

Antibacterial and Antioxidant Activity of Essential Oils from Citrus spp  

Microsoft Academic Search

The antibacterial and antioxidant activities of essential oils from Bitter orange, Sweet orange, Lemon and Mandarin were investigated. The antimicrobial capability of these oils was determined against ten strains of Gram-negative and Gram-positive bacteria, including some phytopathogenic strains. The antibacterial activity of the oils was expressed as minimum inhibitory concentrations (MICs). All oils showed good antibacterial activity against both Gram-negative

S. Frassinetti; L. Caltavuturo; M. Cini; C. M. Della Croce; B. E. Maserti

2011-01-01

55

In Vitro Antimicrobial Activities of Novel Anilinouracils Which Selectively Inhibit DNA Polymerase III of Gram-Positive Bacteria  

Microsoft Academic Search

The 6-anilinouracils are novel dGTP analogs that selectively inhibit the replication-specific DNA polymerase III of gram-positive eubacteria. Two specific derivatives, IMAU (6-(3*-iodo-4*-methylanilino)uracil) and EMAU (6-(3*-ethyl-4*-methylanilino)uracil), were substituted with either a hydroxybutyl (HB) or a methoxy- butyl (MB) group at their N3 positions to produce four agents: HB-EMAU, MB-EMAU, HB-IMAU, and MB-IMAU. These four new agents inhibited Staphylococcus aureus, coagulase-negative staphylococci,

JENNIFER S. DALY; THEODORE J. GIEHL; NEAL C. BROWN; CHENGXIN ZHI; GEORGE E. WRIGHT; RICHARD T. ELLISON III

2000-01-01

56

The Preparation and Antibacterial Activity of 3,3 '=Bis(Trifluoromethyl)-Tetranitrodiphenylamine.  

National Technical Information Service (NTIS)

A new organic substance, 3,3'-Bis(trifluoromethyl)tetranitrodiphenylamine has been synthesized and found to possess antibacterial activity against a number of Gram-positive organisms and against both sulfadiazine-resistant and sensitive strains of Neisser...

J. J. Fritsch C. E. Moore T. S. Meyer I. L. Shklair L. F. Devine

1969-01-01

57

In Vitro Activities of Daptomycin, Vancomycin, Quinupristin- Dalfopristin, Linezolid, and Five Other Antimicrobials against 307 Gram-Positive Anaerobic and 31 Corynebacterium Clinical Isolates  

Microsoft Academic Search

The activities of daptomycin, a cyclic lipopeptide, and eight other agents were determined against 338 strains of gram-positive anaerobic bacteria and corynebacteria by the NCCLS reference agar dilution method with supplemented brucella agar for the anaerobes and Mueller-Hinton agar for the corynebacteria. The dapto- mycin MICs determined on Ca2-supplemented (50 mg\\/liter) brucella agar plates were one- to fourfold lower than

Ellie J. C. Goldstein; Diane M. Citron; C. Vreni Merriam; Yumi A. Warren; Kerrin L. Tyrrell; Helen T. Fernandez

2003-01-01

58

In vitro Activity of Monoclonal and Recombinant Yeast Killer Toxin-like Antibodies Against Antibiotic-resistant Gram-positive Cocci  

Microsoft Academic Search

Background: Monoclonal (mAbKT) and recom- binant single-chain (scFvKT) anti-idiotypic anti- bodies were produced to represent the internal image of a yeast killer toxin (KT) characterized by a wide spectrum of antimicrobial activity, including Gram-positive cocci. Pathogenic eukaryotic and prokaryotic microorganisms, such as Candida albi- cans, Pneumocystis carinii, and a multidrug-resistant strain of Mycobacterium tuberculosis, presenting spe- cific, although yet undefined,

S. Conti; W. Magliani; S. Arseni; E. Dieci; A. Salati; P. E. Varaldo; L. Polonelli

2000-01-01

59

Isolation and Characterization of Microsphaera multipartita gen. nov., sp. nov., a Polysaccharide-Accumulating Gram-Positive Bacterium from Activated Sludge  

Microsoft Academic Search

A new gram-positive bacterium was isolated from activated sludge acclimated with sugar-containing syn- thetic wastewater. This organism, designated strain Y-104T (T = type strain), was a coccus-shaped, aerobic chemoorganotroph that had a strictly respiratory type of metabolism with oxygen as the terminal electron acceptor. This strain accumulates large amounts of polysaccharide in its cells. Strain Y-104T has the following chemotaxonomic

YUKIHIKO YOSHIM; AURA HIRAISHI; KAZUNORI NAKAMUFU

60

Expanding the use of a fluorogenic method to determine activity and mode of action of Bacillus thuringiensis bacteriocins against Gram-positive and Gram-negative bacteria.  

PubMed

Previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by Mexican strains of Bacillus thuringiensis against B. cereus 183. Here we standardize this method to efficiently determine the activity of bacteriocins against both Gram-positive and Gram-negative bacteria. It was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is, ~4 × 10(8) cell/mL and ~7 × 10(8) cell/mL, respectively, for target Gram-positive and Gram-negative bacteria. Comparative analyses of the fluorogenic and traditional well-diffusion assays showed correlation coefficients of 0.88 to 0.99 and 0.83 to 0.99, respectively, for Gram-positive and Gram-negative bacteria. The fluorogenic method demonstrated that the five bacteriocins of B. thuringiensis have bacteriolytic and bacteriostatic activities against all microorganisms tested, including clinically significant bacteria such as Listeria monocytogenes, Proteus vulgaris, and Shigella flexneri reported previously to be resistant to the antimicrobials as determined using the well-diffusion protocol. These results demonstrate that the fluorogenic assay is a more sensitive, reliable, and rapid method when compared with the well-diffusion method and can easily be adapted in screening protocols for bacteriocin production by other microorganisms. PMID:22919330

de la Fuente-Salcido, Norma M; Barboza-Corona, J Eleazar; Espino Monzón, A N; Pacheco Cano, R D; Balagurusamy, N; Bideshi, Dennis K; Salcedo-Hernández, Rubén

2012-01-01

61

Expanding the Use of a Fluorogenic Method to Determine Activity and Mode of Action of Bacillus thuringiensis Bacteriocins Against Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by Mexican strains of Bacillus thuringiensis against B. cereus 183. Here we standardize this method to efficiently determine the activity of bacteriocins against both Gram-positive and Gram-negative bacteria. It was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is, ~4?×?108?cell/mL and ~7?×?108?cell/mL, respectively, for target Gram-positive and Gram-negative bacteria. Comparative analyses of the fluorogenic and traditional well-diffusion assays showed correlation coefficients of 0.88 to 0.99 and 0.83 to 0.99, respectively, for Gram-positive and Gram-negative bacteria. The fluorogenic method demonstrated that the five bacteriocins of B. thuringiensis have bacteriolytic and bacteriostatic activities against all microorganisms tested, including clinically significant bacteria such as Listeria monocytogenes, Proteus vulgaris, and Shigella flexneri reported previously to be resistant to the antimicrobials as determined using the well-diffusion protocol. These results demonstrate that the fluorogenic assay is a more sensitive, reliable, and rapid method when compared with the well-diffusion method and can easily be adapted in screening protocols for bacteriocin production by other microorganisms.

de la Fuente-Salcido, Norma M.; Barboza-Corona, J. Eleazar; Espino Monzon, A. N.; Pacheco Cano, R. D.; Balagurusamy, N.; Bideshi, Dennis K.; Salcedo-Hernandez, Ruben

2012-01-01

62

Antibacterial activity of traditional Australian medicinal plants  

Microsoft Academic Search

Fifty-six ethanolic extracts of various parts of 39 plants used in traditional Australian Aboriginal medicine were investigated for their antibacterial activities against four Gram-positive (Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus and Streptococcus pyogenes) and four Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella typhimurium) bacterial species. In a plate-hole diffusion assay, 12 extracts inhibited the growth of one or

Enzo A Palombo; Susan J Semple

2001-01-01

63

Synthesis and antibacterial activity of 9-substituted minocycline derivatives.  

PubMed

A number of 9-acylamino and 9-sulfonylamino derivatives of minocycline have been synthesized for structure-activity relationship studies. These compounds showed activity against both tetracycline-susceptible and tetracycline-resistant strains. Many of the 9-sulfonylamino derivatives exhibited improved antibacterial activity against a number of tetracycline- and minocycline-resistant Gram-positive pathogens. PMID:16246559

Sum, Phaik-Eng; Ross, Adma T; Petersen, Peter J; Testa, Raymond T

2006-01-15

64

Antibacterial and photocatalytic activities of TiO2 nanotubes  

Microsoft Academic Search

TiO2 nanotubes have been prepared by anodisation of titanium foil and their antibacterial activities have been tested against Gram-positive bacteria (Bacillus atrophaeus) while photocatalytic activity was tested for the degradation of the methyl orange dye. We found that the annealing temperature strongly affected antibacterial activity and photocatalytic dye degradation, as well as the production of reactive oxygen species under illumination.

Charis May Ngor Chan; Alan Man Ching Ng; Man Kin Fung; Hoi Sing Cheng; Mu Yao Guo; Aleksandra B. Djuriši?; Frederick Chi Ching Leung; Wai Kin Chan

2012-01-01

65

The molecular switch that activates the cell wall anchoring step of pilus assembly in gram-positive bacteria.  

PubMed

Cell surface pili in gram-positive bacteria orchestrate the colonization of host tissues, evasion of immunity, and the development of biofilms. Recent work revealed that pilus assembly is a biphasic process wherein pilus polymerization is catalyzed by a pilus-specific sortase followed by cell wall anchoring of the pilus that is promoted by the housekeeping sortase. Here, we present molecular genetic and biochemical studies of a heterotrimeric pilus in Corynebacterium diphtheriae, uncovering the molecular switch that terminates pilus polymerization in favor of cell wall anchoring. The prototype pilus contains a major pilin (SpaA) forming the shaft, a tip pilin (SpaC), and another minor pilin (SpaB). Cells lacking SpaB form pilus fibers, but they are largely secreted in the medium, a phenotype also observed when cells lack the housekeeping sortase. Furthermore, the average pilus length is greatly increased in the absence of SpaB. Remarkably, a SpaB mutant that lacks the cell wall sorting signal but contains a critical lysine residue is incorporated in the pilus. However, the resulting pili fail to anchor to the cell wall. We propose that a specific minor pilin acts as the terminal subunit in pilus assembly. Cell wall anchoring ensues when the pilus polymer assembled on the pilus-specific sortase is transferred to the minor pilin presented by the housekeeping sortase via lysine-mediated transpeptidation. PMID:18779588

Mandlik, Anjali; Das, Asis; Ton-That, Hung

2008-09-16

66

Highly selective antibacterial activities of silver nanoparticles against Bacillus subtilis.  

PubMed

Silver nanoparticles (AgNPs) with different sizes (5, 15 and 55 nm) were synthesized via simple method, and characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray microanalysis (EDX) and ultraviolet-visible absorption spectroscopy (UV-Vis). The antibacterial activities of the prepared AgNPs against Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) were evaluated by inhibition zone, inhibition curve, and colony counting methods. The results showed that the AgNPs exhibited obvious bacterium-selective and size-dependent antibacterial activities. The Gram-positive bacteria S. aureus and B. subtilis were more sensitive to AgNPs than Gram-negative bacterium E. coli. Interestingly, AgNPs displayed remarkably antibacterial activities against B. subtilis among Gram-positive bacteria, regardless of whether in separately or cocultured bacteria. It also showed that AgNPs with 5 nm in size presented the highest antibacterial activity against both Gram-negative and Gram-positive bacteria. The effects of AgNPs on the membrane leakage of the reducing sugars from three bacteria were also measured by 3,5-dinitrosalicylic acid method. The leakage amount of reducing sugars from B. subtilis was the highest among the tested bacteria, indicating that AgNPs could damage the structure of bacteria cell membrane and resulted in the leakage of reducing sugars, leading to the death of bacteria. PMID:24245147

Li, Ju; Rong, Kaifeng; Zhao, Huiping; Li, Fei; Lu, Zhong; Chen, Rong

2013-10-01

67

Antibacterial activity of Thymus daenensis methanolic extract.  

PubMed

Medicinal plants are potential of antimicrobial compounds. The present study deals with the antibacterial activity of methanolic extract of Thymus daenensis. Aerial parts of the plant were collected from Alvand mountainside (Hamadan, Iran) in May 2005, air-dried and extracted by methanol. The dried extract was redissolved in methanol to make a 100 mg/ml solution and then filtered. Antibacterial activity of the extract was evaluated against various Gram-positive and Gram-negatives bacteria using disk diffusion technique. Blank paper disks were loaded with 40 microl of the methanol solution and then dried up. The impregnated disks were placed on Mueller-Hinton agar inoculated with bacterial suspension equal to 0.5 McFarland. The extract inhibited the growth Gram-positive bacteria, i.e., Staphylococcus aureus, Micrococcus luteus, Entrococcus faecalis, Streptococcus pyogenes, but it showed no activity against Gram-negative bacteria. The most significant effect was seen against S.aureus including MRSA, which are important nosocomial pathogens. MIC90 of the extract was determined against Gram-positive bacteria (3.12 mg/ml) and 11 MRSA strain (1.56 mg/ml). PMID:18614414

Mojab, Faraz; Poursaeed, Mahshid; Mehrgan, Hadi; Pakdaman, Shima

2008-07-01

68

Cytotoxicity and antibacterial activity of Sida rhombifolia (Malvaceae) grown in Bangladesh.  

PubMed

The cytotoxicity and antibacterial activities of crude extracts from the leaves of Sida rhombifolia were investigated. The ethyl acetate extract showed potent cytotoxicity with LC50 values (5.41 ppm) comparable to the reference standard, gallic acid. All the extracts showed weak antibacterial activity against both Gram-positive and Gram-negative test organisms. PMID:13680839

Islam, M Ekramul; Haque, M Ekramul; Mosaddik, M A

2003-09-01

69

Alternating electric fields combined with activated carbon for disinfection of Gram negative and Gram positive bacteria in fluidized bed electrode system.  

PubMed

Strong electric fields for disinfection of wastewaters have been employed already for several decades. An innovative approach combining low strength (7 V/cm) alternating electric fields with a granular activated carbon fluidized bed electrode (FBE) for disinfection was presented recently. For disinfection performance of FBE several pure microbial cultures were tested: Bacillus subtilis, Bacillus subtilis subsp. subtilis, Enterococcus faecalis as representatives from Gram positive bacteria and Erwinia carotovora, Pseudomonas luteola, Pseudomonas fluorescens and Escherichia coli YMc10 as representatives from Gram negative bacteria. The alternating electric field amplitude and shape were kept constant. Only the effect of alternating electric field frequency on disinfection performance was investigated. From the bacteria tested, the Gram negative strains were more susceptible and the Gram positive microorganisms were more resistant to FBE disinfection. The collected data indicate that the efficiency of disinfection is frequency and strain dependent. During 6 h of disinfection, the decrease above 2 Log units was achieved with P. luteola and E. coli at 10 kHz and at dual frequency shift keying (FSK) modulated signal with frequencies of 10 kHz and 140 kHz. FBE technology appears to offer a new way for selective bacterial disinfection, however further optimizations are needed on treatment duration, and energy input, to improve effectiveness. PMID:24012021

Racyte, Justina; Bernard, Séverine; Paulitsch-Fuchs, Astrid H; Yntema, Doekle R; Bruning, Harry; Rijnaarts, Huub H M

2013-10-15

70

A new hybrid bacteriocin, Ent35-MccV, displays antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria  

PubMed Central

Bacteriocins and microcins are ribosomally synthesized antimicrobial peptides that are usually active against phylogenetically related bacteria. Thus, bacteriocins are active against Gram-positive while microcins are active against Gram-negative bacteria. The narrow spectrum of action generally displayed by bacteriocins from lactic acid bacteria represents an important limitation for the application of these peptides as clinical drugs or as food biopreservatives. The present study describes the design and expression of a novel recombinant hybrid peptide combining enterocin CRL35 and microcin V named Ent35–MccV. The chimerical bacteriocin displayed antimicrobial activity against enterohemorrhagic Escherichia coli and Listeria monocytogenes clinical isolates, among other pathogenic bacteria. Therefore, Ent35–MccV may find important applications in food or pharmaceutical industries.

Acuna, Leonardo; Picariello, Gianluca; Sesma, Fernando; Morero, Roberto D.; Bellomio, Augusto

2012-01-01

71

Traditional medicine in North Côte-d’Ivoire: screening of 50 medicinal plants for antibacterial activity  

Microsoft Academic Search

Sixty-seven crude ethanol extracts from 50 plants (31 families), which are used in North Côte-d’Ivoire as traditional remedies for bacterial diseases, were screened for in vitro activity against Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Staphyloccocus aureus, Enterococcus faecalis, Streptococcus pyogenes and Bacillus subtilis) bacteria. Thirty-one extracts showed antibacterial activity only on Gram positive bacteria. Of these,

W. M Koné; K. Kamanzi Atindehou; C Terreaux; K Hostettmann; D Traoré; M Dosso

2004-01-01

72

Regulated RNA stability in the Gram positives  

PubMed Central

Regulation of bacterial gene expression at the post-transcriptional level has emerged as a major control mechanism, although not yet as well recognized as the mechanisms of control at the transcriptional level. In this article, we focus on regulated RNA decay in the control of gene expression in Gram-positive organisms, with a focus on Bacillus subtilis. Discovery of new ribonuclease activities in B. subtilis and other Gram-positive species, especially the dual-functioning RNase J1, which specifies both an endonuclease activity and the long-sought bacterial 5’-to-3’ exoribonuclease activity, has led to the recognition of intriguing mechanisms of gene regulation at the level of RNA decay.

Condon, Ciaran; Bechhofer, David H.

2011-01-01

73

[Susceptibility of clinical strains of gram-positive bacteria to selected beta-lactam antibiotics].  

PubMed

The aim of the study was to determine the activity of four beta-lactam antibiotics against nosocomial strains of Gram-positive bacteria. Two antibiotics combined with beta-lactamase inhibitors: timentin (TIC/CLAV) and tazocin (PIP/TZB) and two carbapenems: imipenem and meropenem were applied. The clinical strains were isolated from patients hospitalized in surgical ward of the National Clinical Hospital No 1 in Warsaw. The strains were identified in the automatic ATB system using ID 32 STAPH, API STREP, API CORYNE and API 20 A strips. The susceptibility of isolates to antibacterial agents was determined in the automatic ATB system using ATB STAPH, ATB STREP and ATB ANA strips. The susceptibility of strains to timentin, tazocin, imipenem and meropenem was tested with disc diffusion method. 111 strains of Gram-positive bacteria were cultured. Staphylococci (49) and enterococci (44) dominated among isolated strains. 33 Staphylococcus spp. strains were identified as methicillin-resistant. The obtained results indicate a significant role of Gram-positive cocci (staphylococci and enterococci) in the aetiology of nosocomial infections. Antibiotics combined with beta-lactamase inhibitors and carbapenems demonstrate broad antibacterial spectrum against clinical strains of Gram-positive bacteria except E. faecium strains. PMID:9857616

Sawicka-Grzelak, A; Rokosz, A

1998-01-01

74

The effect of systematic structural modifications on the antibacterial activity of novel oxazolidinones.  

PubMed

A novel series of tetraethylene glycol (TEG) triazolyl and squaramide containing oxazolidinones were synthesized and tested for their antibacterial activity against a selected panel of Gram-positive and Gram-negative bacteria. The 4-TEG-triazolyl derivatives were prepared by 'click reaction'. The introduction of the TEG and squaramide groups did not favor antibacterial activity. The three nucleoside-containing oxazolidinones were also prepared by 'click' methodology resulted in weak antibacterial activity. PMID:21235519

Pintér, Gábor; Bereczki, Ilona; Roth, Elizabeth; Sipos, Attila; Varghese, Reny; Udo, Edet Ekpenyong; Ostorházi, Eszter; Rozgonyi, Ferenc; Phillips, Oludotun Adebayo; Herczegh, Pál

2011-01-01

75

Isolation and Purification of Enterocin E-760 with Broad Antimicrobial Activity against Gram-Positive and Gram-Negative Bacteria?  

PubMed Central

Strain NRRL B-30745, isolated from chicken ceca and identified as Enterococcus durans, Enterococcus faecium, or Enterococcus hirae, was initially identified as antagonistic to Campylobacter jejuni. The isolate produced a 5,362-Da bacteriocin (enterocin) that inhibits the growth of Salmonella enterica serovar Enteritidis, S. enterica serovar Choleraesuis, S. enterica serovar Typhimurium, S. enterica serovar Gallinarum, Escherichia coli O157:H7, Yersinia enterocolitica, Citrobacter freundii, Klebsiella pneumoniae, Shigella dysenteriae, Pseudomonas aeruginosa, Proteus mirabilis, Morganella morganii, Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes, Campylobacter jejuni, and 20 other Campylobacter species isolates. The enterocin, E-760, was isolated and purified by cation-exchange and hydrophobic-interaction chromatographies. The proteinaceous nature of purified enterocin E-760 was demonstrated upon treatment with various proteolytic enzymes. Specifically, the antimicrobial peptide was found to be sensitive to beta-chymotrypsin, proteinase K, and papain, while it was resistant to lysozyme and lipase. The enterocin demonstrated thermostability by retaining activity after 5 min at 100°C and was stable at pH values between 5.0 and 8.7. However, activity was lost below pH 3.0 and above pH 9.5. Administration of enterocin E-760-treated feed significantly (P < 0.05) reduced the colonization of young broiler chicks experimentally challenged and colonized with two strains of C. jejuni by more than 8 log10 CFU. Enterocin E-760 also significantly (P < 0.05) reduced the colonization of naturally acquired Campylobacter species in market age broiler chickens when administered in treated feed 4 days prior to analysis.

Line, J. E.; Svetoch, E. A.; Eruslanov, B. V.; Perelygin, V. V.; Mitsevich, E. V.; Mitsevich, I. P.; Levchuk, V. P.; Svetoch, O. E.; Seal, B. S.; Siragusa, G. R.; Stern, N. J.

2008-01-01

76

Actividades citotóxicas y antibacterianas de las raíces de Capparis zeylanica Linn Antibacterial and Cytotoxic Activities of Capparis zeylanica Linn Roots  

Microsoft Academic Search

Crude extracts and a fatty acid, octadec-7-en-5-ynoic acid (1), from the root bark of Capparis zeylanica Linn. (Fam. Capparidaceae) were screened for their antibacterial activities against Gram positive and Gram negative bacteria. Among the crude extracts, chloroform extract showed good activity against all test organisms. The fatty acid (1) isola- ted from chloroform extract exhibited antibacterial activities against test organisms

HAQUE M; RAHMAN MM; KHONDKAR P

77

In vitro activity of tigecycline (GAR-936) tested against 11,859 recent clinical isolates associated with community-acquired respiratory tract and gram-positive cutaneous infections.  

PubMed

Tigecycline is a novel 9-t-butylglycylamido derivative of minocycline that has demonstrated activity against a variety of bacterial pathogens, including resistant isolates, during preclinical studies. In vitro activities of tigecycline and comparators were tested against 11,859 recent (2000 and 2002) bacterial strains recovered from patients in 29 countries with community-acquired respiratory tract disease (3,317 gram-positive and -negative strains) and skin and soft tissue infections (8,542 gram-positive strains). All oxacillin-susceptible and -resistant Staphylococcus aureus (5,077 strains; tigecycline MIC(90), 0.5 microg/mL) and coagulase-negative staphylococci (1,432 strains; MIC(90), 0.5 microg/mL), penicillin-susceptible and -resistant Streptococcus pneumoniae (1,585 strains; MIC(90), < or =0.25 microg/mL), viridans group streptococci (212 strains; MIC(90), < or =0.25-0.5 microg/mL), vancomycin-susceptible and -resistant enterococci (1,416 strains; MIC(90), 0.25-0.5 microg/mL), beta-haemolytic streptococci (405 strains; MIC(90), < or =0.25 microg/mL), beta-lactamase positive and negative Haemophilus influenzae (1,220 strains; MIC(90), 1 microg/mL), Moraxella catarrhalis (495 strains; MIC(90), 0.25 microg/mL), and Neisseria meningitidis (17 strains; MIC(90), < or =0.12 microg/mL) were inhibited by 2 microg/mL or less of tigecycline. Whereas potency of tetracycline and doxycycline markedly dropped in various resistant organism subsets, tigecycline was unaffected with an overall MIC(90) of 0.5 microg/mL. These findings confirm that tigecycline maintains a truly broad spectrum like the tetracycline class while enhancing potency. It also incorporates stability to the commonly occurring tetracycline resistance mechanisms, making it an attractive candidate for continued clinical development against pathogens causing serious community-acquired respiratory tract infections, as well as cutaneous infections. PMID:15246511

Fritsche, Thomas R; Kirby, Jeffrey T; Jones, Ronald N

2004-07-01

78

In Vitro Antibacterial and Antifungal Activity of Salicylanilide Benzoates  

PubMed Central

The resistance to antimicrobial agents brings a need of novel antimicrobial agents. We have synthesized and found the in vitro antibacterial activity of salicylanilide esters with benzoic acid (2-(phenylcarbamoyl)phenyl benzoates) in micromolar range. They were evaluated in vitro for the activity against eight fungal and eight bacterial species. All derivatives showed a significant antibacterial activity against Gram-positive strains with minimum inhibitory concentrations ?0.98??mol/L including methicillin-resistant Staphylococcus aureus strain. The most active compounds were 5-chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl benzoate and 4-chloro-2-(4-(trifluoromethyl)phenylcarbamoyl)phenyl benzoate. The antifungal activity is significantly lower.

Kratky, Martin; Vinsova, Jarmila; Buchta, Vladimir

2012-01-01

79

Antibacterial activity and chemical constitutions of Ziziphora clinopodioides  

Microsoft Academic Search

The essential oil and methanol extract obtained from aerial parts of Ziziphora clinopodioides Lam. harvested in the Eastern part of Turkey were evaluated for their chemical composition and antibacterial activity against 52 Gram-positive and Gram-negative bacteria. The GC–MS analyses allowed 18 compounds to be determined; the main constituents of the essential oils were (+)-pulegone (31.86%), 1,8-cineole (12.21%), limonene (10.48%), menthol

Suzan Ozturk; Sezai Ercisli

2007-01-01

80

In vivo efficacy of trovafloxacin (CP-99,219), a new quinolone with extended activities against gram-positive pathogens, Streptococcus pneumoniae, and Bacteroides fragilis.  

PubMed Central

The interesting in vitro antimicrobial activity and pharmacokinetics of the new quinolone trovafloxacin (CP-99,219) warranted further studies to determine its in vivo efficacy in models of infectious disease. The significance of the pharmacokinetic and in vitro antimicrobial profiles of trovafloxacin was shown through efficacy in a series of animal infection models by employing primarily oral therapy. Against acute infections, trovafloxacin was consistently more effective than temafloxacin, ciprofloxacin, and ofloxacin against Streptococcus pneumoniae and other gram-positive pathogens while maintaining activity comparable to that of ciprofloxacin against gram-negative organisms. In a model of murine pneumonia, trovafloxacin was more efficacious than temafloxacin, while ciprofloxacin failed against S. pneumoniae (50% protective doses, 2.1, 29.5, and >100 mg/kg, respectively). In addition to its inherent in vitro potency advantage against S. pneumoniae, these data were supported by a pharmacokinetic study that showed levels of trovafloxacin in pulmonary tissue of S. pneumoniae-infected CF1 mice to be considerably greater than those of temafloxacin and ciprofloxacin (twice the maximum drug concentration in serum; two to three times the half-life, and three to six times the area under the concentration-time curve). Against localized mixed anaerobic infections, trovafloxacin was the only agent to effectively reduce the numbers of recoverable CFU of Bacteroides fragilis ( >1,000-fold), Staphylococcus aureus (1,000-fold), and Escherichia coli ( >100-fold) compared with ciprofloxacin, vancomycin, metronidazole, clindamycin, cefoxitin, and ceftriaxone. The in vitro and in vivo antimicrobial activities of trovafloxacin and its pharmacokinetics in laboratory animals provide support for the ongoing and planned human phase II and III clinical trials.

Girard, A E; Girard, D; Gootz, T D; Faiella, J A; Cimochowski, C R

1995-01-01

81

Antibacterial activity of silver bionanocomposites synthesized by chemical reduction route  

PubMed Central

Background The aim of this study is to investigate the functions of polymers and size of nanoparticles on the antibacterial activity of silver bionanocomposites (Ag BNCs). In this research, silver nanoparticles (Ag NPs) were incorporated into biodegradable polymers that are chitosan, gelatin and both polymers via chemical reduction method in solvent in order to produce Ag BNCs. Silver nitrate and sodium borohydride were employed as a metal precursor and reducing agent respectively. On the other hand, chitosan and gelatin were added as a polymeric matrix and stabilizer. The antibacterial activity of different sizes of silver nanoparticles was investigated against Gram-positive and Gram-negative bacteria by the disk diffusion method using Mueller-Hinton Agar. Results The properties of Ag BNCs were studied as a function of the polymer weight ratio in relation to the use of chitosan and gelatin. The morphology of the Ag BNCs films and the distribution of the Ag NPs were also characterized. The diameters of the Ag NPs were measured and their size is less than 20 nm. The antibacterial trait of silver/chitosan/gelatin bionanocomposites was investigated. The silver ions released from the Ag BNCs and their antibacterial activities were scrutinized. The antibacterial activities of the Ag BNC films were examined against Gram-negative bacteria (E. coli and P. aeruginosa) and Gram-positive (S. aureus and M. luteus) by diffusion method using Muller-Hinton agar. Conclusions The antibacterial activity of Ag NPs with size less than 20 nm was demonstrated and showed positive results against Gram-negative and Gram-positive bacteria. The Ag NPs stabilized well in the polymers matrix.

2012-01-01

82

Antimicrobial activity of Calendula officinalis petal extracts against fungi, as well as Gram-negative and Gram-positive clinical pathogens.  

PubMed

The aim of the present study was to assess the antimicrobial activity of methanol and ethanol extracts of pot marigold (Calendula officinalis) petals against clinical pathogens. The antimicrobial potential of C. officinalis extracts was evaluated against a panel of microorganisms isolated from patients at the Belfast City Hospital (BCH), including bacteria and fungi, using disc diffusion assay. Methanol extract of C. officinalis exhibited better antibacterial activity against most of the bacteria tested, than ethanol extract. Both methanol and ethanol extracts showed excellent antifungal activity against tested strains of fungi, while comparing with Fluconazole. PMID:22789794

Efstratiou, Efstratios; Hussain, Abdullah I; Nigam, Poonam S; Moore, John E; Ayub, Muhammad A; Rao, Juluri R

2012-08-01

83

Antibacterial activity of linoleic and oleic acids isolated from Helichrysum pedunculatum: a plant used during circumcision rites  

Microsoft Academic Search

The antibacterial activity-guided fractionation of the dichloromethane extract of leaves of Helichrysum pedunculatum resulted in the isolation of linoleic and oleic acids. Linoleic acid inhibited the growth of all the Gram-positive bacterial species tested with the minimum inhibitory concentration (MIC) varying between 0.01 and 1.0 mg\\/ml. Oleic acid was active against three of the five Gram-positive bacteria at a MIC

F Dilika; P. D Bremner; J. J. M Meyer

2000-01-01

84

In Vitro Activity of Ceftaroline against Gram-Positive and Gram-Negative Pathogens Isolated from Patients in Canadian Hospitals in 2009?  

PubMed Central

The in vitro activities of ceftaroline and comparative agents were determined for a collection of the most frequently isolated bacterial pathogens from hospital-associated patients across Canada in 2009 as part of the ongoing CANWARD surveillance study. In total, 4,546 isolates from 15 sentinel Canadian hospital laboratories were tested using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. Compared with other cephalosporins, including ceftobiprole, cefepime, and ceftriaxone, ceftaroline exhibited the greatest potency against methicillin-susceptible Staphylococcus aureus (MSSA), with a MIC90 of 0.25 ?g/ml. Ceftaroline also demonstrated greater potency than ceftobiprole against community-associated methicillin-resistant S. aureus (MRSA) (MIC90, 0.5 ?g/ml) and health care-associated MRSA (MIC90, 1 ?g/ml) and was at least 4-fold more active than other cephalosporins against Staphylococcus epidermidis; all isolates of MSSA and MRSA tested were susceptible to ceftaroline (MIC, ?1 ?g/ml). Against streptococci, including Streptococcus pneumoniae, ceftaroline MICs (MIC90, ?0.03 ?g/ml) were comparable to those of ceftobiprole; however, against penicillin-nonsusceptible, macrolide-nonsusceptible, and multidrug-nonsusceptible isolates of S. pneumoniae, ceftaroline demonstrated 2- to 4-fold and 4- to 16-fold more potent activities than those of ceftobiprole and ceftriaxone, respectively. All isolates of S. pneumoniae tested were susceptible to ceftaroline (MIC, ?0.25 ?g/ml). Among Gram-negative isolates, ceftaroline demonstrated potent activity (MIC90, ?0.5 ?g/ml) against Escherichia coli (92.2% of isolates were susceptible), Klebsiella pneumoniae (94.1% of isolates were susceptible), Proteus mirabilis (97.7% of isolates were susceptible), and Haemophilus influenzae (100% of isolates were susceptible). Ceftaroline demonstrated less potent activity (MIC90, ?4 ?g/ml) against Enterobacter spp., Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella oxytoca, Serratia marcescens, and Stenotrophomonas maltophilia. Overall, ceftaroline demonstrated potent in vitro activity against a recent collection of the most frequently encountered Gram-positive and Gram-negative isolates from patients attending hospitals across Canada in 2009.

Karlowsky, James A.; Adam, Heather J.; DeCorby, Melanie R.; Lagace-Wiens, Philippe R. S.; Hoban, Daryl J.; Zhanel, George G.

2011-01-01

85

In vitro activity of ceftaroline against gram-positive and gram-negative pathogens isolated from patients in Canadian hospitals in 2009.  

PubMed

The in vitro activities of ceftaroline and comparative agents were determined for a collection of the most frequently isolated bacterial pathogens from hospital-associated patients across Canada in 2009 as part of the ongoing CANWARD surveillance study. In total, 4,546 isolates from 15 sentinel Canadian hospital laboratories were tested using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. Compared with other cephalosporins, including ceftobiprole, cefepime, and ceftriaxone, ceftaroline exhibited the greatest potency against methicillin-susceptible Staphylococcus aureus (MSSA), with a MIC?? of 0.25 ?g/ml. Ceftaroline also demonstrated greater potency than ceftobiprole against community-associated methicillin-resistant S. aureus (MRSA) (MIC??, 0.5 ?g/ml) and health care-associated MRSA (MIC??, 1 ?g/ml) and was at least 4-fold more active than other cephalosporins against Staphylococcus epidermidis; all isolates of MSSA and MRSA tested were susceptible to ceftaroline (MIC, ?1 ?g/ml). Against streptococci, including Streptococcus pneumoniae, ceftaroline MICs (MIC??, ?0.03 ?g/ml) were comparable to those of ceftobiprole; however, against penicillin-nonsusceptible, macrolide-nonsusceptible, and multidrug-nonsusceptible isolates of S. pneumoniae, ceftaroline demonstrated 2- to 4-fold and 4- to 16-fold more potent activities than those of ceftobiprole and ceftriaxone, respectively. All isolates of S. pneumoniae tested were susceptible to ceftaroline (MIC, ?0.25 ?g/ml). Among Gram-negative isolates, ceftaroline demonstrated potent activity (MIC??, ?0.5 ?g/ml) against Escherichia coli (92.2% of isolates were susceptible), Klebsiella pneumoniae (94.1% of isolates were susceptible), Proteus mirabilis (97.7% of isolates were susceptible), and Haemophilus influenzae (100% of isolates were susceptible). Ceftaroline demonstrated less potent activity (MIC??, ?4 ?g/ml) against Enterobacter spp., Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella oxytoca, Serratia marcescens, and Stenotrophomonas maltophilia. Overall, ceftaroline demonstrated potent in vitro activity against a recent collection of the most frequently encountered Gram-positive and Gram-negative isolates from patients attending hospitals across Canada in 2009. PMID:21402844

Karlowsky, James A; Adam, Heather J; Decorby, Melanie R; Lagacé-Wiens, Philippe R S; Hoban, Daryl J; Zhanel, George G

2011-06-01

86

Activity of daptomycin against susceptible and multidrug-resistant Gram-positive pathogens collected in the SECURE study (Europe) during 2000-2001  

Microsoft Academic Search

Antibiotic resistance was prevalent in Gram-positive pathogens collected from 40 sites in 15 European countries during 2000-2001. Among Staphylococcus aureus, 27.3% of all isolates submitted were resistant to oxacillin and ranged from 0% of isolates from the Netherlands to 36.9% of isolates from Portugal. The overall prevalence of vancomycin-resistant Enterococcus faecium was 25.1%, with Italy submitting the largest percentage of

Ian A. Critchley; Deborah C. Draghi; Daniel F. Sahm; Clyde Thornsberry; Mark E. Jones; James A. Karlowsky

87

(+)-agelasine D: improved synthesis and evaluation of antibacterial and cytotoxic activities.  

PubMed

An improved synthesis of (+)-agelasine D (10) from (+)-manool is reported together with cytotoxic and antibacterial data for agelasine D and structurally close synthetic analogues. These compounds display a broad spectrum of antibacterial activities including effects on M. tuberculosis and Gram-positive and Gram-negative bacteria (both aerobes and anaerobes). They exhibit profound cytotoxic activity against several cancer cells, including a multidrug-resistant cell line. (+)-Agelasine D (10) has been isolated earlier from a marine sponge (Agelas sp.). PMID:16562840

Vik, Anders; Hedner, Erik; Charnock, Colin; Samuelsen, Orjan; Larsson, Rolf; Gundersen, Lise-Lotte; Bohlin, Lars

2006-03-01

88

Antibacterial activity of ethanolic and aqueous extracts of Acacia aroma Gill. ex Hook et Arn  

Microsoft Academic Search

The purpose of the present study was to investigate the antibacterial activity of seven ethanolic extracts and three aqueous extracts from various parts (leaves, stems and flowers) of A. aroma against 163 strains of antibiotic multi-resistant bacteria.The disc diffusion assay was performed to evaluate antibacterial activity of the A. aroma crude extracts, against several Gram-positive bacteria (E. faecalis, S. aureus,

M. E Arias; J. D Gomez; N. M Cudmani; M. A Vattuone; M. I Isla

2004-01-01

89

Antibacterial activity of Aegle marmelos against leaf, bark and fruit extracts.  

PubMed

The antibacterial activity of the methanol, chloroform and aqueous extracts from the leaves, bark and fruit of A. marmelos was studied using disc diffusion method against Bacillus subtilis, Staphylococcus aureus (Gram Positive), Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Salmonella paratyphi A and Salmonella paratyphi B (Gram Negative). Results suggest that the methanolic extract has significant antibacterial activity against tested bacteria. The present study justifies the claimed uses of A. marmelos in the traditional system of medicine to treat various infectious diseases. PMID:22557272

Poonkothai, M; Saravanan, M

2008-01-01

90

Synthesis and in vitro antibacterial activity of oxazolidine LBM-415 analogs as peptide deformylase inhibitors.  

PubMed

The drug resistant bacteria pose a severe threat to human health. The increasing resistance of those pathogens to traditional antibacterial therapy renders the identification of new antibacterial agents with novel antibacterial mechanisms an urgent need. In this study, a series of (2S)-N-substituted-1-[(formyhydroxyamino)methyl]-1-oxohexyl]-2-oxazolidinecarboxamides were designed, synthesized and evaluated for in vitro antibacterial activity. Most of these compounds displayed good activities against Gram-positive organisms comparable to reference agent LBM-415. PMID:21288715

Yu, Linliang; Zhou, Weicheng; Wang, Zhenyu

2011-03-01

91

Screening of antibacterial activity of Amaicha del Valle (Tucumán, Argentina) propolis  

Microsoft Academic Search

Propolis is extensively used in Argentine folk medicine. Alcoholic extracts of propolis from four localities of Amaicha del Valle (El Paraiso, La Banda Este, La Banda Oeste and El Molino), Province of Tucumán and from Cerrillos, Province of Santiago del Estero, Argentina were prepared. All showed antibacterial activity against Gram positive bacteria, the propolis from La Banda Este being the

M. I. Nieva Moreno; M. I. Isla; N. G. Cudmani; M. A. Vattuone; A. R. Sampietro

1999-01-01

92

The antibacterial activity of biogenic silver and its mode of action  

Microsoft Academic Search

In a previous study, biogenic silver nanoparticles were produced by Lactobacillus fermentum which served as a matrix preventing aggregation. In this study the antibacterial activity of this biogenic silver was compared to ionic silver and chemically produced nanosilver. The minimal inhibitory concentration (MIC) was tested on Gram-positive and Gram-negative bacteria and was comparable for biogenic silver and ionic silver ranging

Liesje Sintubin; Bart De Gusseme; Paul Van der Meeren; Benny F. G. Pycke; Willy Verstraete; Nico Boon

2011-01-01

93

Synergistic antibacterial activity between Thymus vulgaris and Pimpinella anisum essential oils and methanol extracts  

Microsoft Academic Search

Essential oils (EOs) and methanol extracts obtained from aerial parts of Thymus vulgaris and Pimpinella anisum seeds were evaluated for their single and combined antibacterial activities against nine Gram-positive and Gram-negative pathogenic bacteria: Staphylococcus aureus, Bacillus cereus, Escherichia coli, Proteus vulgaris, Proteus mirabilis, Salmonella typhi, Salmonella typhimurium, Klebsiella pneumoniae and Pseudomonas aeruginosa. The essential oils and methanol extracts revealed promising

Firas A. Al-Bayati

2008-01-01

94

Tyrosine Mediated Gold, Silver and Their Alloy Nanoparticles Synthesis: Antibacterial Activity Toward Gram Positive and Gram Negative Bacterial Strains  

Microsoft Academic Search

Shape and size-controlled synthesis of metal and metal alloy nanoparticles have gained significant attention due to their unique physico-chemical properties. Most of these synthesis routes have thus far explored use of toxic chemicals for metal nanoparticles synthesis, which limit their biological applications. With the increasing focus on eco-friendly routes towards nanomaterials synthesis and their biological applications, we show that metal

Hemant K. Daima; P. R. Selvakannan; Zahra Homan; Suresh K. Bhargava; Vipul Bansal

2011-01-01

95

Ceftriaxone activity against Gram-positive and Gram-negative pathogens isolated in US clinical microbiology laboratories from 1996 to 2000: results from The Surveillance Network® (TSN®) Database-USA  

Microsoft Academic Search

Ceftriaxone was introduced into clinical practice in the USA in 1985 and was the first extended-spectrum (third-generation) cephalosporin approved for once-daily treatment of patients with Gram-positive or Gram-negative infections. Review of ceftriaxone activity is important given its continued use since the mid-1980s and reports of emerging resistance among all antimicrobial agent classes. We reviewed the activity of ceftriaxone and relevant

J. A. Karlowsky; M. E. Jones; D. C. Mayfield; C. Thornsberry; D. F. Sahm

2002-01-01

96

Antibacterial activity of head-to-head bis-benzimidazoles.  

PubMed

Symmetric bis-benzimidazole (BBZ) conjugates were profiled for activity against a range of Gram-positive and Gram-negative bacteria. para-Substituted ethoxy, amino and methoxy derivatives displayed potent bacteriostatic activity against meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, streptococci and Listeria monocytogenes. Moderate to good activity was also found against mycobacteria; two compounds were strongly active against logarithmic phase and hypoxia-induced latent Mycobacterium tuberculosis. No compound displayed significant activity towards Gram-negative bacteria. Only high concentrations of antibacterial BBZs showed cytotoxic effects towards fibroblasts, and the most active compound was well tolerated by zebrafish embryos. PMID:23837928

Moreira, Joao B; Mann, John; Neidle, Stephen; McHugh, Timothy D; Taylor, Peter W

2013-10-01

97

Identification of a new family of enzymes with potential O-acetylpeptidoglycan esterase activity in both Gram-positive and Gram-negative bacteria  

PubMed Central

Background The metabolism of the rigid bacterial cell wall heteropolymer peptidoglycan is a dynamic process requiring continuous biosynthesis and maintenance involving the coordination of both lytic and synthetic enzymes. The O-acetylation of peptidoglycan has been proposed to provide one level of control on these activities as this modification inhibits the action of the major endogenous lytic enzymes, the lytic transglycosylases. The O-acetylation of peptidoglycan also inhibits the activity of the lysozymes which serve as the first line of defense of host cells against the invasion of bacterial pathogens. Despite this central importance, there is a dearth of information regarding peptidoglycan O-acetylation and nothing has previously been reported on its de-acetylation. Results Homology searches of the genome databases have permitted this first report on the identification of a potential family of O-Acetylpeptidoglycan esterases (Ape). These proteins encoded in the genomes of a variety of both Gram-negative and Gram-positive bacteria, including a number of important human pathogens such as species of Neisseria, Helicobacter, Campylobacter, and Bacillus anthracis, have been organized into three families based on amino acid sequence similarities with family 1 being further divided into three sub-families. The genes encoding these proteins are shown to be clustered with Peptidoglycan O-acetyltransferases (Pat) and in some cases, together with other genes involved in cell wall metabolism. Representative bacteria that encode the Ape proteins were experimentally shown to produce O-acetylated peptidoglycan. Conclusion The hypothetical proteins encoded by the pat and ape genes have been organized into families based on sequence similarities. The Pat proteins have sequence similarity to Pseudomonas aeruginosa AlgI, an integral membrane protein known to participate in the O-acetylation of the exopolysaccaride, alginate. As none of the bacteria that harbor the pat genes produce alginate, we propose that the Pat proteins serve to O-acetylate peptidoglycan which is known to be a maturation event occurring in the periplasm. The Ape sequences have amino acid sequence similarity to the CAZy CE 3 carbohydrate esterases, a family previously known to be composed of only O-acetylxylan esterases. They are predicted to contain the ?/? hydrolase fold associated with the GDSL and TesA hydrolases and they possess the signature motifs associated with the catalytic residues of the CE3 esterases. Specific signature sequence motifs were identified for the Ape proteins which led to their organization into distinct families. We propose that by expressing both Pat and Ape enzymes, bacteria would be able to obtain a high level of localized control over the degradation of peptidoglycan through the attachment and removal of O-linked acetate. This would facilitate the efficient insertion of pores and flagella, localize spore formation, and control the level of general peptidoglycan turnover.

Weadge, Joel T; Pfeffer, John M; Clarke, Anthony J

2005-01-01

98

Comparative In Vitro Activities of SMT19969, a New Antimicrobial Agent, against Clostridium difficile and 350 Gram-Positive and Gram-Negative Aerobic and Anaerobic Intestinal Flora Isolates  

PubMed Central

The comparative in vitro activity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-defined Clostridium difficile strains, 174 Gram-positive and 136 Gram-negative intestinal anaerobes, and 40 Gram-positive aerobes. SMT19969 was one dilution more active against C. difficile isolates (MIC range, 0.125 to 0.5 ?g/ml; MIC90, 0.25 ?g/ml), including ribotype 027 strains, than fidaxomicin (range, 0.06 to 1 ?g/ml; MIC90, 0.5 ?g/ml) and two to six dilutions lower than either vancomycin or metronidazole. SMT19969 and fidaxomicin were generally less active against Gram-negative anaerobes, especially the Bacteroides fragilis group species, than vancomycin and metronidazole, suggesting that SMT19969 has a lesser impact on the normal intestinal microbiota that maintain colonization resistance. SMT19969 showed limited activity against other Gram-positive anaerobes, including Bifidobacteria species, Eggerthella lenta, Finegoldia magna, and Peptostreptococcus anaerobius, with MIC90s of >512, >512, 64, and 64 ?g/ml, respectively. Clostridium species showed various levels of susceptibility, with C. innocuum being susceptible (MIC90, 1 ?g/ml) and C. ramosum and C. perfringens being nonsusceptible (MIC90, >512 ?g/ml). Activity against Lactobacillus spp. (range, 0.06 to >512 ?g/ml; MIC90, >512 ?g/ml) was comparable to that of fidaxomicin and varied by species and strain. Gram-positive aerobic cocci (Staphylococcus aureus, Enterococcus faecalis, E. faecium, and streptococci) showed high SMT19969 MIC90 values (128 to >512 ?g/ml).

Citron, Diane M.; Tyrrell, Kerin L.; Merriam, C. Vreni

2013-01-01

99

Synthesis and antibacterial activity of doxycycline neoglycosides.  

PubMed

A set of 37 doxycycline neoglycosides were prepared, mediated via a C-9 alkoxyamino-glycyl-based spacer reminiscent of that of tigecycline. Subsequent in vitro antibacterial assays against representative drug-resistant Gram negative and Gram positive strains revealed a sugar-dependent activity profile and one doxycycline neoglycoside, the 2'-amino-?-D-glucoside conjugate, to rival that of the parent pharmacophore. In contrast, the representative tetracycline-susceptible strain E. coli 25922 was found to be relatively responsive to a range of doxycycline neoglycosides. This study also extends the use of aminosugars in the context of neoglycosylation via a simple two-step strategy anticipated to be broadly applicable for neoglycorandomization. PMID:23987662

Zhang, Jianjun; Ponomareva, Larissa V; Marchillo, Karen; Zhou, Maoquan; Andes, David R; Thorson, Jon S

2013-09-27

100

Comparison of antibacterial activity in the hemolymph of marine bivalves from Galicia (NW Spain).  

PubMed

A screening study of in vitro antibacterial activity was conducted in marine bivalves with economical importance and widespread along the coast of Galicia (NW Spain). Hemocyte lysate supernatant (HLS) and plasma of Mytilus galloprovincialis, Ostrea edulis, Crassostrea gigas, Ruditapes decussatus, Ruditapes philippinarum, and Cerastoderma edule were incubated with Vibrio splendidus and Micrococcus sp. HLS and plasma for all the species demonstrated antibacterial activity, and C. edule had the highest activity per unit of protein in these hemolymph fractions. Significant differences were not found between HLS and plasma activities. Furthermore, antibacterial activity against Micrococcus sp. (Gram-positive) was stronger than against V. splendidus (Gram-negative). PMID:21134379

Casas, Sandra M; Comesaña, Pilar; Cao, Asunción; Villalba, Antonio

2011-02-01

101

Antimicrobial Resistance in Gram-Positive Bacteria  

Microsoft Academic Search

Gram-positive bacteria are common causes of bloodstream and other infections in hospitalized patients in the United States, and the percentage of nosocomial bloodstream infections caused by antibiotic-resistant gram-positive bacteria is increasing. Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are of particular concern. In the United States, approximately 60% of staphylococcal infections in the intensive care unit are now caused

Louis B. Rice

2006-01-01

102

Synthesis and Antibacterial Activity of Novel Curcumin Derivatives Containing Heterocyclic Moiety  

PubMed Central

A series of curcumin derivatives containing heterocyclic moiety have been synthesized and evaluated for their antibacterial activities. The chemical structures of the synthesized compounds were verified on the basis of spectral data and elemental analyses. Investigation of antimicrobial activity of the derivatives demonstrated the ability to inhibit Gram-positive microorganisms with zone of inhibition ranging from 14-18 mm, MIC ranging between 0.0625 and 0.25 mg/mL. Among all tested derivatives, diazepine 4 exhibited remarkable potency against Gram-positive bacteria S. aureus. An extensive study is underway to optimize the effectiveness of diazepine type of compounds and to determine their mode of action.

A. Hamed, Othman; Mehdawi, Noha; Abu Taha, Adham; M. Hamed, Emad; A. Al-Nuri, Mohammed; S. Hussein, Ayman

2013-01-01

103

Synthesis and in vitro evaluation of substituted phenyl-piperazinyl-phenyl oxazolidinones against Gram-positive bacteria.  

PubMed

With the incidence of linezolid-resistant Enterococcus faecalis, E. faecium and Staphylococcus aureus, modification of linezolid at the 5- and/or 3-positions led to the development of a series of 3-(methoxyl-phenyl)-piperazinyl-phenyl oxazolidinone analogues. These compounds were tested in vitro against six gram-positive standard organisms (S. aureus, S. epidermidis, S. pneumoniae, S. albus, Streptococcus enteridis and S. nonhemolyticus). 5-acetylaminomethyl oxazolidinones bearing fluorine at 3'-position of phenyl ring showed activities against several gram-positive bacteria (MIC: 3.13-6.25 mug/mL). The position of methoxyl group on the phenyl ring of piperazine group affected antibacterial spectrum. 3-(4'- (para-methoxyl-phenyl)-piperazinyl)-(3'-fluoro)-phenyl-5-acetylaminomethyl oxazolidinone was found active against 5 gram-positive organisms except S. nonhemolyticus, whereas 3-(4'-(ortho-methoxyl-phenyl)-piperazinyl)-(3'-fluoro)-phenyl-5-acetylaminomethyl oxazolidinone was found active only against 2 gram-positive organisms, namely S. albus, S. enteridis. PMID:17461974

Liu, Jidong; He, Baoyuan; Yu, Aizhen; Zhou, Weicheng

2007-04-01

104

Isolation and antibacterial activity of phenylpropanoid derivatives from Ballota nigra.  

PubMed

In addition to the previously isolated phenylpropanoid glycosides verbascoside 1, forsythoside B 2, arenarioside 3 and ballotetroside 4, another four compounds were isolated from generative aerial parts of Ballota nigra: three phenylpropanoid glycosides, alyssonoside 5, lavandulifolioside 6 and angoroside A 7 and a non-glycosidic derivative (+)-(E)-caffeoyl-L-malic acid 8. The antibacterial activity of the five major compounds (1-4 and 8) was tested against gram-positive and gram-negative bacteria. Three of them (1-3) exhibited a moderate antimicrobial activity against Proteus mirabilis and Staphylococcus aureus including one methicillin-resistant strain. PMID:10619384

Didry, N; Seidel, V; Dubreuil, L; Tillequin, F; Bailleul, F

1999-11-01

105

Investigations on Antibacterial Activity of Leaf Extracts of Azadirachta indica A. Juss (Meliaceae): A Traditional Medicinal Plant of India  

Microsoft Academic Search

The present study was carried out to screen and evaluate antimicrobial activity of leaf extracts of Azadirachta indica A. Juss. Petroleum ether, dichloromethane, chloroform, ethanol and aqueous extract of leaves of A. indica were tested against selected Gram positive and Gram negative bacterial species. Phytochemical leaf extracts of A. indica exhibited significant anti-bacterial activity against all the test microorganisms. However,

2008-01-01

106

Antibacterial activity in Actinidia chinensis, Feijoa sellowiana and Aberia caffra.  

PubMed

The antibacterial activity of extracts from various parts of plants (leaves, fruits and stems) was studied in Actinidia chinensis, Feijoa sellowiana and Aberia caffra. These are tropical plants used for food. The fruits (subdivided into skin, pulp and seeds), leaves and stems were separately extracted and tested, in triplicate, against eight Gram positive and Gram negative bacterial strains. All the extracts, except from the leaves of A. caffra, showed activity against all the strains employed. Inhibition of bacterial growth was tested against Na-cefotaxime, benzyl penicillin and tetracycline. The antibiotic activity of fruit resides essentially in the seeds. The antibacterial activity of extracts from vegetative plant parts was generally less active that from fruit extracts. The minimum inhibiting concentration (MIC) and minimum bactericidal concentration (MBC) were determined for all the extracts and showed exclusively bacteriostatic activity. PMID:18611802

Basile, A; Vuotto, M L; Violante, U; Sorbo, S; Martone, G; Castaldo-Cobianchi, R

1997-01-01

107

Synthesis and in vitro antibacterial activity of (2S)-N-(substitutedphenyl)-1-[(2R)-2-[(formylhydroxyamino)methyl]-1-oxohexyl]-2-pyrrolidinecarboxamides as potential peptide deformylase inhibitors.  

PubMed

Gram-positive organisms have re-emerged as the major hospital pathogens, which make the unmet medical needs for antibacterial therapy even worse. In searching for potent agents against Gram-positive pathogens, novel (2S)-N-(substitutedphenyl)-1-[(2R)-2-[(formylhydroxyamino)methyl]-1-oxohexyl]-2-pyrrolidinecarboxamides, analogues of peptide deformylase inhibitor LBM-415 were designed, synthesized and evaluated for their antibacterial activities in vitro. Many of these compounds exhibited high potency against Gram-positive organisms compared with reference agent: LBM-415. PMID:19152643

Wang, Zhenyu; Zhou, Weicheng

2009-01-01

108

Antibacterial activity of essential oils from palmarosa, evening primrose, lavender and tuberose.  

PubMed

Essential oils extracted from flower petals of palmarosa (Cymbopogon martini), evening primrose (Primula rosea), lavender (Lavandula angustifolia) and tuberose (Polianthus tuberosa) were tested for their antibacterial activities against gram-positive and gram-negative bacteria. Different concentrations of each essential oil ranging from 10-100% were tested. Both gram-positive and gram-negative bacteria were found susceptible to the studied flower essential oils. With increase in concentration of essential oil, increase in zone of inhibition was observed thus dose-dependent response was clear for each essential oil. Essential oil extracted from Cymbopogon martini showed the highest activity against both gram positive and gram negative bacteria among the tested essential oils. PMID:20336210

Lodhia, M H; Bhatt, K R; Thaker, V S

2009-03-01

109

Antibacterial Activity of Essential Oils from Palmarosa, Evening Primrose, Lavender and Tuberose  

PubMed Central

Essential oils extracted from flower petals of palmarosa (Cymbopogon martini), evening primrose (Primula rosea), lavender (Lavandula angustifolia) and tuberose (Polianthus tuberosa) were tested for their antibacterial activities against gram-positive and gram-negative bacteria. Different concentrations of each essential oil ranging from 10-100% were tested. Both gram-positive and gram-negative bacteria were found susceptible to the studied flower essential oils. With increase in concentration of essential oil, increase in zone of inhibition was observed thus dose-dependent response was clear for each essential oil. Essential oil extracted from Cymbopogon martini showed the highest activity against both gram positive and gram negative bacteria among the tested essential oils.

Lodhia, M. H.; Bhatt, K. R.; Thaker, V. S.

2009-01-01

110

In Vitro Activity and Microbiological Efficacy of Tedizolid (TR-700) against Gram-Positive Clinical Isolates from a Phase 2 Study of Oral Tedizolid Phosphate (TR-701) in Patients with Complicated Skin and Skin Structure Infections  

PubMed Central

Tedizolid (TR-700, formerly torezolid) is the active moiety of the prodrug tedizolid phosphate (TR-701), a next-generation oxazolidinone, with high potency against Gram-positive species, including methicillin-resistant Staphylococcus aureus (MRSA). A recently completed randomized, double-blind phase 2 trial evaluated 200, 300, or 400 mg of oral tedizolid phosphate once daily for 5 to 7 days in patients with complicated skin and skin structure infections. This report examines the in vitro activity of tedizolid and Zyvox (linezolid) against Gram-positive pathogens isolated at baseline and describes the microbiological and clinical efficacy of tedizolid. Of 196 isolates tested, 81.6% were S. aureus, and of these, 76% were MRSA. The MIC50 and MIC90 of tedizolid against both methicillin-susceptible S. aureus (MSSA) and MRSA were 0.25 ?g/ml, compared with a MIC50 of 1 ?g/ml and MIC90 of 2 ?g/ml for linezolid. For coagulase-negative staphylococci (n = 7), viridans group streptococci (n = 15), and beta-hemolytic streptococci (n = 3), the MICs ranged from 0.03 to 0.25 ?g/ml for tedizolid and from 0.12 to 1 ?g/ml for linezolid. The microbiological eradication rates at the test-of-cure visit (7 to 14 days posttreatment) in the microbiologically evaluable population (n = 133) were similar in all treatment groups, with overall eradication rates of 97.7% for all pathogens, 97.9% for MRSA, and 95.7% for MSSA. The clinical cure rates for MRSA and MSSA infections were 96.9% and 95.7%, respectively, across all dose groups. This study confirms the potent in vitro activity of tedizolid against pathogenic Gram-positive cocci, including MRSA, and its 4-fold-greater potency in comparison with linezolid. All dosages of tedizolid phosphate showed excellent microbiological and clinical efficacy against MRSA and MSSA.

Prokocimer, Philippe; Bien, Paul; DeAnda, Carisa; Pillar, Chris M.

2012-01-01

111

Ethanol production in Gram-positive microbes  

DOEpatents

The subject invention concerns the transformation of Gram-positive bacteria with heterologous genes which confer upon these microbes the ability to produce ethanol as a fermentation product. Specifically exemplified is the transformation of bacteria with genes, obtainable from Zymomonas mobilis, which encode pyruvate decarboxylase and alcohol dehydrogenase. 2 figs.

Ingram, L.O.; Barbosa-Alleyne, M.D.F.

1999-06-29

112

In vitro Antibacterial Activity of DR3355, the S-(––)Isomer of Ofloxacin  

Microsoft Academic Search

DR-3355, the S-(––)-isomer of ofloxacin, possessed generally twice higher activity than ofloxacin, and its action was bactericidal. The difference in antibacterial activity of these compounds was attributable to their inhibitory activity against DNA gyrase. DR-3355 was characterized by its higher potency against gram-positive cocci and obligate anaerobes than ofloxacin and ciprofloxacin. DR-3355 was somewhat less potent than ciprofloxacin against Entewbacteriaceae

Teruo Fujimoto; Susumu Mitsuhashi

1990-01-01

113

Antibacterial activity of a virgatusin-related compound.  

PubMed

The relationship between antibacterial activity of tetra-substituted tetrahydrofuran lignans (1-4) and their absolute configurations was tested. Only compound 4 among two virgatusins and two related compounds exhibited growth inhibitory activity against the Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus and Listeria denitrificans. Compound 4 affected the growth of B. subtilis in a bactericidic manner, and its ability to dissipate the cytoplasmic membrane potential was investigated using the fluorescence probe 3,3'-dipropylthiadicarbocyanine iodide. These results suggested that compound 4 damages cells by causing the loss of the proton motive force and disruption of the cellular integrity of the membrane, leading to cell death. In addition, it was shown that the antibacterial activity of a lignan was closely related to its absolute configuration and functional groups. PMID:17341839

Maruyama, Masafumi; Yamauchi, Satoshi; Akiyama, Koichi; Sugahara, Takuya; Kishida, Taro; Koba, Yojiro

2007-03-01

114

Chemical Composition, Antibacterial and Antimutagenic Activities of Essential Oil from (Tunisian) Cyperus rotundus  

Microsoft Academic Search

Essential oil from the tubers of Cyperus rotundus, obtained by steam distillation, was analyzed by GC and GC\\/MS. In total, 33 compounds were identified. The oil was characterized by its high content of sesquiterpenes with cyperene (30.9%) being major. The antibacterial activity of oil from tubers of Cyperus rotundus, showed more important activity against Gram-positive bacteria specially Staphylococcus aureus than

Soumaya Kilani; Afef Abdelwahed; Ribai Ben Ammar; Nawel Hayder; Kamel Ghedira; Imed Chraief; Mohamed Hammami; Leila Chekir-Ghedira

2005-01-01

115

Surface-conjugated antimicrobial peptide leucocin a displays high binding to pathogenic gram-positive bacteria.  

PubMed

Leucocin A, a representative class IIa bacteriocin, is a ribosomally synthesized antimicrobial peptide (AMP) that displays potent activity against specific gram-positive bacteria. The antibacterial activity of such peptides is preceded by the binding event that can be utilized for studying specific peptide-bacteria interactions. In this study, 37-residue Leucocin A (LeuA) was synthesized using solid-phase peptide synthesis and covalently immobilized on gold substrates from either the N- or C-terminal. Both the peptide monolayers on gold substrates were incubated separately with five strains of gram-positive bacteria and displayed differential binding to different strains with highest binding to pathogenic Listeria monocytogenes . The C-terminally immobilized LeuA showed higher bacterial binding compared to the N-terminally attached LeuA. The full length immobilized LeuA (37-residue) was active as well as displayed higher bacterial binding (73 ± 6 bacteria/100 ?m(2)) compared to 24-residue inactive LeuA fragment (40 ± 8 bacteria/100 ?m(2)) from the C-terminal region. The high and specific bacterial binding ability of LeuA functionalized surfaces support the potential use of class IIa bacteriocins in antimicrobial peptide-based diagnostic platforms. PMID:24359454

Etayash, Hashem; Norman, Lana; Thundat, Thomas; Stiles, Michael; Kaur, Kamaljit

2014-01-22

116

The antibacterial and antifungal activity of a soda-lime glass containing silver nanoparticles.  

PubMed

The antibacterial and antifungal activity of a low melting point soda-lime glass powder containing silver nanoparticles has been studied. Nano-Ag sepiolite fibres containing monodispersed silver nanoparticles (d(50) approximately 11 +/- 9 nm) were used as the source of silver. This powder presents a high antibacterial (against gram-positive and gram-negative bacteria) as well as antifungal (against I. orientalis) activity. The observed high activity against yeast has been explained by considering the inhibitory effect of the Ca(2+) lixiviated from the glass on the growth of the yeast colonies. PMID:19417439

Esteban-Tejeda, L; Malpartida, F; Esteban-Cubillo, A; Pecharromán, C; Moya, J S

2009-02-25

117

The antibacterial and antifungal activity of a soda-lime glass containing silver nanoparticles  

NASA Astrophysics Data System (ADS)

The antibacterial and antifungal activity of a low melting point soda-lime glass powder containing silver nanoparticles has been studied. Nano-Ag sepiolite fibres containing monodispersed silver nanoparticles (d50?11 ± 9 nm) were used as the source of silver. This powder presents a high antibacterial (against gram-positive and gram-negative bacteria) as well as antifungal (against I. orientalis) activity. The observed high activity against yeast has been explained by considering the inhibitory effect of the Ca2+ lixiviated from the glass on the growth of the yeast colonies.

Esteban-Tejeda, L.; Malpartida, F.; Esteban-Cubillo, A.; Pecharromán, C.; Moya, J. S.

2009-02-01

118

Special features of gram-positive bacterial eradication by photosensitizers.  

PubMed

Antibiotic resistance of pathogenic bacteria is a major concern and presents a special challenge for development of alternative antibacterial modalities. One of these alternative approaches is based on using the photodynamic therapy (PDT) for eradicating bacteria. Photosensitizer-induced PDT exhibits unique properties and demonstrates efficient microbe-killing effects. The efficient and irreversible antimicrobial effects of PDT are not dependent on the antibiotic susceptibility of the pathogenic bacteria to antibiotics. Gram-positive bacteria exhibit efficient binding of the photosensitizer to the bacterial barriers, leading to immediate photoinactivation of the bacteria. Photoinactivation of Gram-positive bacteria by various photosensitizers has become a high priority, since these bacteria are responsible for life-threatening infections in humans, especially in the elderly and in compromised hosts in whom they cause hospital-acquired infections. The present review concentrates on the photoinactivation of Staphylococi, Streptococci, Propionibacterium acnes, Deinococcus radiodurans, aerobic spore-forming Bacilli by various photosensitizers and by various methods described in numerous works and patents. PMID:23550546

Nitzan, Yeshayahu; Nisnevitch, Marina

2013-08-01

119

Preliminary report on the in vitro antibacterial activity of Bryophyllum pinnatum leaf juice.  

PubMed

The juice from the leaves of Bryophyllum pinnatum S. Kurtz (Crassulaceae) was tested for antibacterial activity. The extract at 5% v/v was bactericidal to a wide spectrum of Gram-positive and Gram-negative bacteria such as Bacillus subtilis, Staphyllococcus aureus, Streptococcus pyogenes; Streptococcus faecalis; Escherichia coli; Proteus spp; Klebsiella spp; Shigella spp; Salmonella spp; Serratia marcescens; and Pseudomonas aeruginosa including the clinical isolates of these organisms possessing multiple antibiotic resistance. PMID:3004181

Obaseiki-Ebor, E E

1985-01-01

120

Size-dependent antimicrobial properties of CuO nanoparticles against Gram-positive and -negative bacterial strains  

PubMed Central

Background 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. Here we synthesized different sized CuO nanoparticles and explored the size-dependent antibacterial activity of each CuO nanoparticles preparation. Methods CuO nanoparticles were synthesized using a gel combustion method. In this approach, cupric nitrate trihydrate and citric acid were dissolved in distilled water with a molar ratio of 1:1. The resulting solution was stirred at 100°C, until gel was formed. The gel was allowed to burn at 200°C to obtain amorphous powder, which was further annealed at different temperatures to obtain different size CuO nanoparticles. We then tested the antibacterial properties using well diffusion, minimum inhibitory concentration, and minimum bactericidal concentration methods. Results XRD spectra confirmed the formation of single phase CuO nanoparticles. Crystallite size was found to increase with an increase in annealing temperature due to atomic diffusion. A minimum crystallite size of 20 nm was observed in the case of CuO nanoparticles annealed at 400°C. Transmission electron microscopy results corroborate well with XRD results. All CuO nanoparticles exhibited inhibitory effects against both Gram-positive and -negative bacteria. The size of the particles was correlated with its antibacterial activity. Conclusion The antibacterial activity of CuO nanoparticles was found to be size-dependent. In addition, the highly stable minimum-sized monodispersed copper oxide nanoparticles synthesized during this study demonstrated a significant increase in antibacterial activities against both Gram-positive and -negative bacterial strains.

Azam, Ameer; Ahmed, Arham S; Oves, M; Khan, MS; Memic, Adnan

2012-01-01

121

Activity of ceftaroline and comparator agents tested against contemporary Gram-positive and -negative (2011) isolates collected in Europe, Turkey, and Israel.  

PubMed

The activity of ceftaroline was tested against 8233 isolates mainly collected from bloodstream, urinary, respiratory and skin and soft tissue specimens in European medical centers during 2011. This cephalosporin displayed activity against Staphylococcus aureus (MIC50, 0·25 mg/l), with greater activity against MRSA (MIC50, 1 mg/l) than other ?-lactams tested. Against Streptococcus pneumoniae, including penicillin-resistant strains, other streptococcal groups and Haemophilus spp., ceftaroline was highly active and MIC90 values ranged from ?0·015 to 0·12 mg/l. Ceftaroline, like other cephalosporins, had limited activity against ESBL-phenotype Enterobacteriaceae, but showed good activity against isolates not displaying an ESBL-phenotype. Ceftaroline remains very active against MRSA and other organisms than could be associated with its approved indications in the EU (complicated skin and soft tissue infections and community-acquired pneumonia). PMID:24070006

Castanheira, Mariana; Jones, Ronald N; Sader, Helio S

2014-08-01

122

In vitro activity of ceftobiprole against frequently encountered aerobic and facultative Gram-positive and Gram-negative bacterial pathogens: results of the CANWARD 2007-2009 study.  

PubMed

The in vitro activity of ceftobiprole was evaluated against 15 011 clinical isolates obtained from patients in Canadian hospitals between 2007 and 2009. All Staphylococcus aureus were susceptible to ceftobiprole (MIC(90)'s for methicillin-susceptible Staphylococcus aureus and methicillin-resistant Staphylococcus aureus of ? 1 ?g/mL and 2 ?g/mL, respectively). Ceftobiprole was active against penicillin-susceptible Streptococcus pneumoniae (MIC(90), ? 0.06 ?g/mL), penicillin-resistant Streptococcus pneumoniae (MIC(90), 0.5 ?g/mL), Streptococcus pyogenes (MIC(90), ? 0.06 ?g/mL), Staphylococcus epidermidis (MIC(90), ? 1 ?g/mL), and Enterococcus faecalis (MIC(90), ? 1 ?g/mL). Over 90% of Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Citrobacter freundii, Proteus mirabilis, and Serratia marcescens isolates were inhibited by a ceftobiprole concentration of ? 1 ?g/mL. Ceftobiprole was not active against extended-spectrum ?-lactamase-producing Escherichia coli and K. pneumoniae. The in vitro activity of ceftobiprole versus Pseudomonas aeruginosa was similar to that of cefepime (MIC(90), 16 ?g/mL). The broad spectrum of activity by ceftobiprole would support further study of this agent in the treatment of hospital-acquired infections. PMID:21353964

Walkty, Andrew; Adam, Heather J; Laverdière, Michel; Karlowsky, James A; Hoban, Daryl J; Zhanel, George G

2011-03-01

123

The in vitro antibacterial activity of dietary spice and medicinal herb extracts.  

PubMed

The in vitro antibacterial activities of a total of 46 extracts from dietary spices and medicinal herbs were investigated by agar-well diffusion method against five foodborne bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella anatum). Their total phenolic contents were also evaluated. Many herb and spice extracts contained high levels of phenolics and exhibited antibacterial activity against foodborne pathogens. Gram-positive bacteria were generally more sensitive to the tested extracts than Gram-negative ones. S. aureus was the most sensitive, while E. coli was the most resistant. There were highly positive relationships (R(2)=0.73-0.93) between antibacterial activities and phenolic content of the tested extracts against each bacterium. This suggested that the antibacterial activity of the tested extracts was closely associated with their phenolic constituents. PMID:17449125

Shan, Bin; Cai, Yi-Zhong; Brooks, John D; Corke, Harold

2007-06-10

124

Caprolactam-silica network, a strong potentiator of the antimicrobial activity of kanamycin against gram-positive and gram-negative bacterial strains.  

PubMed

Here, we report the fabrication of a novel ?-caprolactam-silica (?-SiO2) network and assessed its biocompatibility and ability to improve the antimicrobial activity of kanamycin. The results of the quantitative antimicrobial assay demonstrate that the obtained ?-SiO2 network has efficiently improved the kanamycin activity on Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 strains, with a significant decrease of the minimum inhibitory concentration. The ?-SiO2 network could be feasibly obtained and represents an alternative for the design of new antibiotic drug carriers or delivery systems to control bacterial infections. PMID:23402978

Voicu, Georgeta; Grumezescu, Valentina; Andronescu, Ecaterina; Grumezescu, Alexandru Mihai; Ficai, Anton; Ficai, Denisa; Ghitulica, Cristina Daniela; Gheorghe, Irina; Chifiriuc, Mariana Carmen

2013-03-25

125

In Vivo Efficacy of Trovafloxacin (CP99,219), a New Quinolone with Extended Activities against Gram-Positive Pathogens, Streptococcus pneumoniae, andBacteroides fragilis  

Microsoft Academic Search

The interesting in vitro antimicrobial activity and pharmacokinetics of the new quinolone trovafloxacin (CP-99,219) warranted further studies to determine its in vivo efficacy in models of infectious disease. The significance of the pharmacokinetic and in vitro antimicrobial profiles of trovafloxacin was shown through efficacy in a series of animal infection models by employing primarily oral therapy. Against acute infections, trovafloxacin

ARTHUR E. GIRARD; DENNIS GIRARD; THOMAS D. GOOTZ; JAMES A. FAIELLA; ANDCAROLINE R. CIMOCHOWSKI

1995-01-01

126

In vitro activity of nadifloxacin against several Gram-positive bacteria and analysis of the possible evolution of resistance after 2 years of use in Germany.  

PubMed

Nadifloxacin has good activity against Propionibacterium acnes as well as against both meticillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) and Staphylococcus epidermidis. The aim of this study was to evaluate the activity of this fluoroquinolone against the abovementioned microorganisms, comparing isolates collected in 2007 in Germany, a country where nadifloxacin has been used for the last 2 years, with isolates collected from 2006-2007 in Spain where nadifloxacin has not been used. A collection of P. acnes from Hungary (strains collected during 2005-2006) and a collection of P. acnes from different countries in Europe (collected during 2002) were also included. The activity of nadifloxacin was compared with ciprofloxacin, erythromycin and clindamycin. Susceptibility testing of P. acnes was performed by agar dilution, whereas the susceptibility of the different staphylococci was determined by microdilution. Although the isolates were collected from three different countries (Spain, Hungary and Germany) where the use of quinolones can produce a different effect, no significant differences in the percentages of resistance to nadifloxacin were observed in P. acnes, MSSA, MRSA and S. epidermidis. Therefore, topical antibiotics such as nadifloxacin do not have an additional effect on resistance. Moreover, nadifloxacin presented much better activity than the comparator drugs used in this study against the studied microorganisms. PMID:19095414

Alba, Veronica; Urban, Edit; Angeles Dominguez, M; Nagy, Elisabeth; Nord, Carl-Erik; Palacín, Celia; Vila, Jordi

2009-03-01

127

In Vitro Activity of Tigecycline against Gram-Positive and Gram-Negative Pathogens as Evaluated by Broth Microdilution and Etest?  

PubMed Central

The current surveillance establishes the activity profile of tigecycline against recent clinical U.S. isolates of target pathogens. Findings from a distributed surveillance that utilized Etest yielded a tigecycline activity profile that varied from that observed in a separate centralized broth microdilution (BMD) surveillance (D. C. Draghi et al., Poster D-0701, 46th Intersci. Conf. Antimicrob. Agents Chemother., San Francisco, CA). Differences were noted among Acinetobacter spp. and Serratia marcescens and, to a lesser extent, with Streptococcus pyogenes. To address whether these differences were due to discordance in testing methodology or to variations among the analyzed populations, isolates from the current surveillance were concurrently tested by BMD and Etest. In all, 1,800 Staphylococcus aureus, 259 S. pyogenes, 226 Streptococcus pneumoniae, 93 Enterococcus faecalis, 1,356 Enterobacteriaceae, and 227 Acinetobacter baumannii strains were evaluated. Tigecycline had potent activity by BMD, with >99.6% susceptibility (%S) observed for all pathogens with interpretive criteria, excluding Enterobacter cloacae (98.3% S) and E. faecalis (86.0% S), and MIC90s ranged from 0.03 ?g/ml (S. pyogenes/S. pneumoniae) to 1 ?g/ml (Enterobacteriaceae/A. baumannii). Similar profiles were observed by Etest, with the exception of A. baumannii, although for most evaluated pathogens Etest MICs trended one doubling-dilution higher than BMD MICs. Major or very major errors were infrequent, and a high degree of essential agreement was observed, excluding A. baumannii, S. marcescens, and S. pneumoniae, for which ?4-fold differences in MICs were observed for 29, 27.1, and 34% of the isolates, respectively. Further analysis regarding the suitability of the tigecycline Etest for testing S. marcescens, Acinetobacter spp., and S. pneumoniae is warranted.

Pillar, Chris M.; Draghi, Deborah C.; Dowzicky, Michael J.; Sahm, Daniel F.

2008-01-01

128

In vitro activity of tigecycline against gram-positive and gram-negative pathogens as evaluated by broth microdilution and Etest.  

PubMed

The current surveillance establishes the activity profile of tigecycline against recent clinical U.S. isolates of target pathogens. Findings from a distributed surveillance that utilized Etest yielded a tigecycline activity profile that varied from that observed in a separate centralized broth microdilution (BMD) surveillance (D. C. Draghi et al., Poster D-0701, 46th Intersci. Conf. Antimicrob. Agents Chemother., San Francisco, CA). Differences were noted among Acinetobacter spp. and Serratia marcescens and, to a lesser extent, with Streptococcus pyogenes. To address whether these differences were due to discordance in testing methodology or to variations among the analyzed populations, isolates from the current surveillance were concurrently tested by BMD and Etest. In all, 1,800 Staphylococcus aureus, 259 S. pyogenes, 226 Streptococcus pneumoniae, 93 Enterococcus faecalis, 1,356 Enterobacteriaceae, and 227 Acinetobacter baumannii strains were evaluated. Tigecycline had potent activity by BMD, with >99.6% susceptibility (%S) observed for all pathogens with interpretive criteria, excluding Enterobacter cloacae (98.3% S) and E. faecalis (86.0% S), and MIC(90)s ranged from 0.03 mug/ml (S. pyogenes/S. pneumoniae) to 1 mug/ml (Enterobacteriaceae/A. baumannii). Similar profiles were observed by Etest, with the exception of A. baumannii, although for most evaluated pathogens Etest MICs trended one doubling-dilution higher than BMD MICs. Major or very major errors were infrequent, and a high degree of essential agreement was observed, excluding A. baumannii, S. marcescens, and S. pneumoniae, for which >/=4-fold differences in MICs were observed for 29, 27.1, and 34% of the isolates, respectively. Further analysis regarding the suitability of the tigecycline Etest for testing S. marcescens, Acinetobacter spp., and S. pneumoniae is warranted. PMID:18596149

Pillar, Chris M; Draghi, Deborah C; Dowzicky, Michael J; Sahm, Daniel F

2008-09-01

129

Antibacterial Activity of Myristica fragrans against Oral Pathogens.  

PubMed

Myristica fragrans Houtt is mostly cultivated for spices in Penang Island, Malaysia. The ethyl acetate and ethanol extracts of flesh, mace and seed of Myristica fragrans was evaluated the bactericidal potential against three Gram-positive cariogenic bacteria (Streptococcus mutans ATCC 25175, Streptococcus mitis ATCC 6249, and Streptococcus salivarius ATCC 13419) and three Gram-negative periodontopathic bacteria (Aggregatibacter actinomycetemcomitans ATCC 29522, Porphyromonas gingivalis ATCC 33277, and Fusobacterium nucleatum ATCC 25586). Antibacterial activities of the extracts was determined by twofold serial microdilution, with minimum inhibitory concentrations (MIC) ranging from 1.25 to 640?mg/mL and 0.075 to 40?mg/mL. The minimum bactericidal concentration (MBC) was obtained by subculturing method. Among all extracts tested, ethyl acetate extract of flesh has the highest significant inhibitory effects against Gram-positive and Gram-negative bacteria with mean MIC value ranging from 0.625 to 1.25 ± 0.00 (SD) mg/mL; P = 0.017) and highest bactericidal effects at mean MBC value ranging from 0.625?mg/mL to 20 ± 0.00 (SD) mg/mL. While for seed and mace of Myristica fragrans, their ethanol extracts exhibited good antibacterial activity against both groups of test pathogens compared to its ethyl acetate extracts. All of the extracts of Myristica fragrans did not show any antibacterial activities against Fusobacterium nucleatum ATCC 25586. Thus, our study showed the potential effect of ethyl acetate and ethanol extracts from flesh, seed and mace of Myristica fragrans to be new natural agent that can be incorporated in oral care products. PMID:23049613

Shafiei, Zaleha; Shuhairi, Nadia Najwa; Md Fazly Shah Yap, Nordiyana; Harry Sibungkil, Carrie-Anne; Latip, Jalifah

2012-01-01

130

[Experimental evaluation of the antibacterial activity of tomato pulp oil extract].  

PubMed

The antibacterial action of the oil extract obtained from tomato pulp has been studied with the use of museum strains Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 5638-P and Candida albicans ATCC 885-653, recommended for the determination of the antibacterial activity of medicinal preparations (State Pharmacopoeia, edition XI), as well as Enterobacter, Streptococcus, Staphylococcus, Klebsiella and Escherichia clinical strains. As revealed in this study, tomato pulp oil extract produces a wide-spectrum antibacterial effect on Gram-positive and Gram-negative microorganisms and on fungi of the genus Candida. The study has determined that this antibacterial action is linked with the presence of a complex of organic acids (succinic, citric, tartaric, etc.). PMID:9949491

Vorob'ev, A A; Seleznev, A S; Pavlova, L A; Kapitanov, A B; Yang, A; Ershova, N N

1998-01-01

131

Biotransformation of clerodane diterpenoids by Rhizopus stolonifer and antibacterial activity of resulting metabolites.  

PubMed

Microbial transformation of clerodane lactone (1) by a plant pathogen fungus, Rhizopus stolonifer, resulted in the production of metabolites 3 and 4. While incubation of clerodane methyl ester (2) by R. stolonifer yielded metabolites 5-8. The structures of the transformed products were determined by the spectroscopic techniques and compounds 4, 7 and 8 were found. The antibacterial activity of clerodane diterpenoids 1 and 2 and their metabolites 3-8 were also studied. The metabolites 3-7 showed moderate activities against both Gram-positive and Gram-negative organisms. While metabolite 8 showed a moderate activity against Gram-positive organisms and a good activity against Gram-negative organisms. PMID:23535269

Iqbal Choudhary, M; Mohammad, Mohammad Yasin; Musharraf, Syed Ghulam; Onajobi, Ismail; Mohammad, Akhtar; Anis, Itrat; Shah, Muhammad Raza; Atta-Ur-Rahman

2013-06-01

132

Pathogenicity of anaerobic gram-positive cocci.  

PubMed Central

The pathogenicity of 20 strains of facultative or anaerobic gram-positive cocci (AGPC) was investigated by injecting them alone or mixed with other flora into mice, utilizing the subcutaneous abscess model. Abscesses induced by a mixture of two organisms were uniformly larger than those induced by single organisms. The relationships among seven AGPC strains, eight aerobes, and two Bacteroides spp. were determined by treating the infected animals with antibiotics and observing the effect of therapy directed against one or both organisms present in the abscess. A total of 70 different combinations were tested. As judged by their responses to antimicrobial therapy, facultative cocci or AGPC were relatively more important than the other species in 6 combinations, equally important in 35 combinations, and less important in 29 combinations. The AGPC most often found to be equal to or more important than the other bacteria were Peptococcus magnus, Streptococcus constellatus, and Peptostreptococcus anaerobius. Proteus mirabilis, Escherichia coli, and Staphylococcus aureus were frequently found to be of more importance than the AGPC.

Brook, I; Walker, R I

1984-01-01

133

A Mysterious Gram-Positive Rods  

PubMed Central

We encountered a patient with a history of intravenous drug use presenting with fever, malaise and nausea who was found to have cavitary lung lesions. Unexpectedly, gram positive rods grew out on day five on multiple blood cultures, which were later identified as Mycobacterium fortuitum. The patient underwent transesophageal echocardiogram, which showed aortic and tricuspid valve vegetations. Liver biopsy demonstrated granulomatous hepatitis. Interestingly, serum alkaline phosphatase level fell with antibiotic treatment. Mycobacterium fortuitum is ubiquitous worldwide, being found in tap water, and soil. M. fortuitum is usually considered as a contaminant. Disseminated infection caused by this bacterium in an immunocompetent host is extremely rare. Most of the disseminated infections have been reported in immune-deficient patients. In immunocompetent people, M. fortuitum causes human infection primarily by direct inoculation, including localized post-traumatic and surgical wound infections, and catheter-related sepsis. Our patient, an HIV-negative intravenous drug user, had Mycobacterium fortuitum sepsis associated with infective endocarditis, septic pulmonary emboli, and granulomatous hepatitis. Interestingly, the patient admitted using tap water occasionally for mixing heroin when her sterile water ran out, which we thought was the likely source of M. fortuitum.

Natsag, Javzandulam; Min, Zaw; Hamad, Yasir; Alkhalil, Bassel; Rahman, Atiq; Williams, Richard

2012-01-01

134

Synthesis and in vitro antibacterial activity of quinolone/naphthyridone derivatives containing 3-alkoxyimino-4-(methyl)aminopiperidine scaffolds.  

PubMed

We report herein the synthesis of a series of 7-[3-alkoxyimino-4-(methyl)aminopiperidin-1-yl]quinolone/naphthyridone derivatives. In vitro antibacterial activity of these derivatives was evaluated against representative strains, and compared with ciprofloxacin (CPFX), levofloxacin (LVFX) and gemifloxacin (GMFX). The results reveal that all of the target compounds 19a-c and 20 have considerable Gram-positive activity, although they are generally less active than the reference drugs against the Gram-negative strains with some exceptions. Especially, novel compounds 19a2, 19a4 and 19a5 were found to show strong antibacterial activity (MICs: <0.008-0.5?g/mL) against all of the tested 15 Gram-positive strains including MRSA, LVFX- and GMFX-resistant MRSE, and CPFX-, LVFX- and GMFX-resistant MSSA. PMID:23402878

Lv, Kai; Wu, Jinwei; Wang, Jian; Liu, Mingliang; Wei, Zengquan; Cao, Jue; Sun, Yexin; Guo, Huiyuan

2013-03-15

135

Antibacterial activity of ethanolic and aqueous extracts of Acacia aroma Gill. ex Hook et Arn.  

PubMed

The purpose of the present study was to investigate the antibacterial activity of seven ethanolic extracts and three aqueous extracts from various parts (leaves, stems and flowers) of A. aroma against 163 strains of antibiotic multi-resistant bacteria. The disc diffusion assay was performed to evaluate antibacterial activity of the A. aroma crude extracts, against several Gram-positive bacteria (E. faecalis, S. aureus, coagulase-negative stahylococci, S. pyogenes, S. agalactiae, S. aureus ATCC 29213, E. faecalis ATCC 29212) and Gram-negative bacteria (E. coli., K. pneumoniae, P. mirabilis, E. cloacae, S. marcescens, M morganii, A. baumannii, P. aeruginosa, S. maltophilia, E. coli ATCC 35218, P. aeruginosa ATCC 27853, E. coli ATCC 25922). All ethanolic extracts showed activity against gram-positive bacteria. Among all obtained extracts, only leaf and flower fluid extracts showed activity against Gram-negative bacteria. Based on this bioassay, leaf fluid extracts tended to be the most potent, followed by flower fluid extracts. Minimal inhibitory concentration (MIC) values of extracts and antibiotics were comparatively determined by agar and broth dilution methods. Both extracts were active against S. aureus, coagulase-negative stahylococci, E. faecalis and E. faecium and all tested Gram-negative bacteria with MIC values from 0.067 to 0.308 mg/ml. In this study the minimal bactericidal concentration (MBC) values were identical or twice as high than the corresponding MIC for leaf extracts and four or eight times higher than MIC values for flower extracts. This may indicate a bactericidal effect. Stored extracts have similar antibacterial activity as recently obtained extracts. The A. aroma extracts of leaves and flowers may be useful as antibacterial agents against Gram- negative and Gram-positive antibiotic multi-resistant microorganisms. PMID:15120571

Arias, M E; Gomez, J D; Cudmani, N M; Vattuone, M A; Isla, M I

2004-05-28

136

Antibacterial activity of Salvia tomentosa essential oil  

Microsoft Academic Search

The essential oil of Salvia tomentosa aerial parts, consisting of 1,8-cineol (17%), ?-caryophyllene (11%), cyclofenchene (10%) and ?-cadinene (6%), was screened for its antimicrobial activity. The essential oil remarkably inhibited the growth of tested Gram-positive and Gram-negative bacteria except for Pseudomonas aeruginosa.

M. Zeki Haznedaroglu; N. Ulku Karabay; Ulvi Zeybek

2001-01-01

137

[Synthesis and antibacterial activity of 7 beta-[2-(2-substituted aminothiazol-4-yl)-(Z)-2-methoxyiminoacetylamido]-3-quaternaryammoniummethyl-cephalosporins].  

PubMed

In order to find new cephalosporin with more and more potent antibacterial activity, nine new fourth-generation cephalosporins (N1-N9) were synthesized from ethyl 2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetate (1) via acylation, substitution, hydrolysis, active esterification, condensation and salt formation. The structures of compounds (N1-N9) were confirmed by IR, MS, 1H NMR and elemental analysis. The target compounds possess different antimicrobial activities against Gram-positive and Gram-negative bacteria. The preliminary results of antibacterial activities revealed that they showed better antibacterial activities against Gram-positive bacteria than cefpirome sulfate. In particular, their activities against Staphylococcus aureus and Streptococcus albus are better. PMID:19545053

Chen, Guo-hua; Yang, Yang; Ren, Zhong; Zhong, Qi-xing

2009-04-01

138

Novel semisynthetic antibiotics from caprazamycins A-G: caprazene derivatives and their antibacterial activity.  

PubMed

Acidic treatment of a mixture of caprazamycins (CPZs) A-G isolated from a screen of novel antimycobacterial agents gave caprazene, a core structure of CPZs, in high yield. Chemical modification of the resulting caprazene was performed to give its various derivatives. The structure-activity relationships of the caprazene derivatives against several mycobacterial species and pathogenic Gram-positive and Gram-negative bacteria were studied. Although caprazene showed no antibacterial activity, the antibacterial activity was restored for its 1'''-alkylamide, 1'''-anilide and 1'''-ester derivatives. Compounds 4b (CPZEN-45), 4d (CPZEN-48), 4f and 4g (CPZEN-51) exhibited more potent activities against Mycobacterium tuberculosis and M. avium complex strains than CPZ-B. These results suggest that caprazene would be a good precursor from which novel semisynthetic antibacterial antibiotics can be designed for the treatment of mycobacterial diseases such as tuberculosis and M. avium complex infection. PMID:23532021

Takahashi, Yoshiaki; Igarashi, Masayuki; Miyake, Toshiaki; Soutome, Hiromi; Ishikawa, Kanae; Komatsuki, Yasuhiro; Koyama, Yoshiko; Nakagawa, Naoko; Hattori, Seiko; Inoue, Kunio; Doi, Norio; Akamatsu, Yuzuru

2013-03-01

139

In Vitro Activity of Plazomicin against 5,015 Gram-Negative and Gram-Positive Clinical Isolates Obtained from Patients in Canadian Hospitals as Part of the CANWARD Study, 2011-2012.  

PubMed

Plazomicin is a next-generation aminoglycoside that is not affected by most clinically relevant aminoglycoside-modifying enzymes. The in vitro activities of plazomicin and comparator antimicrobials were evaluated against a collection of 5,015 bacterial isolates obtained from patients in Canadian hospitals between January 2011 and October 2012. Susceptibility testing was performed using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method, with MICs interpreted according to CLSI breakpoints, when available. Plazomicin demonstrated potent in vitro activity against members of the family Enterobacteriaceae, with all species except Proteus mirabilis having an MIC90 of ?1 ?g/ml. Plazomicin was active against aminoglycoside-nonsusceptible Escherichia coli, with MIC50 and MIC90 values identical to those for aminoglycoside-susceptible isolates. Furthermore, plazomicin demonstrated equivalent activities versus extended-spectrum ?-lactamase (ESBL)-producing and non-ESBL-producing E. coli and Klebsiella pneumoniae, with 90% of the isolates inhibited by an MIC of ?1 ?g/ml. The MIC50 and MIC90 values for plazomicin against Pseudomonas aeruginosa were 4 ?g/ml and 16 ?g/ml, respectively, compared with 4 ?g/ml and 8 ?g/ml, respectively, for amikacin. Plazomicin had an MIC50 of 8 ?g/ml and an MIC90 of 32 ?g/ml versus 64 multidrug-resistant P. aeruginosa isolates. Plazomicin was active against methicillin-susceptible and methicillin-resistant Staphylococcus aureus, with both having MIC50 and MIC90 values of 0.5 ?g/ml and 1 ?g/ml, respectively. In summary, plazomicin demonstrated potent in vitro activity against a diverse collection of Gram-negative bacilli and Gram-positive cocci obtained over a large geographic area. These data support further evaluation of plazomicin in the clinical setting. PMID:24550325

Walkty, A; Adam, H; Baxter, M; Denisuik, A; Lagacé-Wiens, P; Karlowsky, J A; Hoban, D J; Zhanel, G G

2014-05-01

140

Early appropriate therapy of Gram-positive bloodstream infections: the conservative use of new drugs.  

PubMed

Among the Gram-positive organisms, meticillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium represent the biggest therapeutic hurdles. The evolution of MRSA exemplifies the genetic adaptation of an organism into a first-class multidrug-resistant pathogen. Glycopeptides such as vancomycin have been the treatment of choice for MRSA, but poor outcomes have frequently been reported, particularly among isolates with higher minimum inhibitory concentrations (MICs) within the susceptible range (< or =2 mg/L). Further more, vancomycin's limitations as an antibacterial agent include slow bactericidal activity and relatively poor tissue penetration. Inadequate dosing may, however, contribute to vancomycin's poor performance; the standard recommendation for trough concentrations of 5-10 mg/L is inadequate for serious infections such as bacteraemia and endocarditis. Trough levels of 15-20 mg/L are probably necessary; however they are often associated with increased nephrotoxicity. Despite the recent dramatic reduction in antibiotic research by pharmaceutical companies, a few compounds have been developed to treat Gram-positive infections. Quinupristin-dalfopristin, although shown to have in vitro activity against MRSA, is not approved by the US Food and Drug Administration for the treatment of MRSA, and cannot be recommended for the treatment of S. aureus bacteraemia, except under exceptional circumstances. Although linezolid and tigecycline may be useful in specific situations, they cannot be routinely recommended for the treatment of MRSA bacteraemia because of safety concerns and very limited available clinical data. Daptomycin has recently been proven to be effective and well tolerated for meticillin-sensitive S. aureus and MRSA bacteraemia, including right-sided endocarditis. PMID:19931814

Grossi, Paolo A

2009-01-01

141

Antibacterial activity of leaves extracts of Trifolium alexandrinum Linn. against pathogenic bacteria causing tropical diseases  

PubMed Central

Objective To investigate antibacterial potential of Trifolium alexandrinum (T. alexandrinum) Linn. against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases. Methods Non-polar and polar extracts of the leaves of T. alexandrinum i.e., hexane, dichloromethane (DCM), ethyl acetate (EtOAc), methanol (MeOH) and aqueous (AQ) extracts at five different concentrations (1, 2, 5, 10 and 15 mg/mL) were prepared to evaluate their antibacterial value. NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method. Results Polar extracts demonstrated significant antibacterial activity against tested pathogens. EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens. While AQ plant extract inhibited the growth of sixteen of the test strains. EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains. Conclusions The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases. Since Egyptian clover is used as a fodder plant, it could be helpful in controlling various infectious diseases associated with cattle as well.

Khan, Abdul Viqar; Ahmed, Qamar Uddin; Shukla, Indu; Khan, Athar Ali

2012-01-01

142

Antibacterial activity of extracts from plants of central Argentina--isolation of an active principle from Achyrocline satureioides.  

PubMed

The great increase in bacterial infections is fueling interest in the search for antibacterial products of plant origin. Extracts obtained from 51 native and naturalized plants from central Argentina were therefore evaluated for their IN VITRO inhibitory activity on pathogenic bacteria with the aim of selecting the most active ones as new sources of effective antibiotics. The susceptibility of reference and clinical strains of Enterococcus faecalis, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus was determined. Extracts from Achyrocline satureioides, Flourensia oolepis, Lepechinia floribunda, and Lithrea molleoides were the most potent, with MIC and MBC values ranging from 0.006 to 2 and 0.012 to 10 mg/mL, respectively, on both gram-positive and negative bacteria. The antibacterial activity-guided isolation of A. satureioides ethanol extract showed 23-methyl-6-O-desmethylauricepyrone (1) to be the most active compound. This compound showed inhibitory effects against gram-positive bacteria with MIC and MBC values of 0.002 and 0.008 mg/mL, respectively, while on gram-negative strains, the MIC and MBC were 0.062-0.250 and 0.062-0.500 mg/mL, respectively. The strong antibacterial activity shown by the four plant extracts or the compound isolated from A. satureioides suggests that they could become part of the arsenal of antibacterial drugs currently used. PMID:20645245

Joray, Mariana B; del Rollán, María R; Ruiz, Gustavo M; Palacios, Sara M; Carpinella, María C

2011-01-01

143

Antibacterial Activity of Sirodesmin PL Phytotoxin: Application to the Selection of Phytotoxin-Deficient Mutants  

PubMed Central

Sirodesmin PL, a phytotoxin and mycotoxin produced by Leptosphaeria maculans, the causal agent of stem-canker disease of crucifers, exhibited antibacterial activity against gram-positive bacteria and particularly Bacillus subtilis. The importance of the disulfide bridge of the molecule in antibacterial activity was demonstrated. A simple and reliable bioassay based on the antibacterial activity of the toxin was performed for screening sirodesmin PL-deficient mutants when grown on solid culture medium. A mutant was selected and found to produce 3,700-fold less toxin than did the wild-type strain. A sensitive procedure for quantification of the toxin by high-pressure liquid chromatography was developed. Levels of product as low as 100 ng could be detected by this procedure. Images

Boudart, Georges

1989-01-01

144

Chemical constituents and antibacterial activity of the leaf essential oil of Feronia limonia.  

PubMed

The essential oil from the leaves of Feronia limonia was extracted and the chemical constituents and antibacterial activity were studied. The GC and GC-MS analyses revealed that the leaf essential oil of F. limonia contained fourteen compounds representing about 98.4% of the total oil. The major chemical compounds identified were Eudesma-4 (14).11-dine (46.3%), carvacrol (29.6%) and 1,5-cyclodecandine (13.4%). The essential oil was screened for its antibacterial activity against different clinically isolated Gram positive and Gram negative bacterial strains by disc diffusion and minimum inhibitory concentration assay. The essential oil exhibited moderate antibacterial activity against all the tested bacterial strains with MIC values ranging from 125 to 500 ?g/mL except Proteus mirabilis. PMID:22815575

Kumar, A Senthil; Venkatesalu, V; Kannathasan, K; Chandrasekaran, M

2010-10-01

145

New polymeric biocides: synthesis and antibacterial activities of polycations with pendant biguanide groups.  

PubMed

Acrylate monomers with pendant biguanide groups were successfully synthesized, and their homopolymers and copolymers were prepared with acrylamide. These cationic disinfectants of polymeric forms exhibited high antibacterial activity against gram-positive bacteria, whereas they were less active against gram-negative bacteria. It was found that the activity of the polymeric disinfectants was much higher than that of the monomeric species, and the difference in activity between the polymers and the monomers was discussed on the basis of their contributions to each elementary process of the lethal action. PMID:6385836

Ikeda, T; Yamaguchi, H; Tazuke, S

1984-08-01

146

Secretory phospholipase A2 in dromedary tears: a host defense against staphylococci and other gram-positive bacteria.  

PubMed

The best known physiologic function of secreted phospholipase A2 (sPLA2) group IIA (sPLA2-IIA) is defense against bacterial infection through hydrolytic degradation of bacterial membrane phospholipids. In fact, sPLA2-IIA effectively kills Gram-positive bacteria and to a lesser extent Gram-negative bacteria and is considered a major component of the eye's innate immune defense system. The antibacterial properties of sPLA2 have been demonstrated in rabbit and human tears. In this report, we have analyzed the bactericidal activity of dromedary tears and the subsequently purified sPLA2 on several Gram-positive bacteria. Our results showed that the sPLA2 displays a potent bactericidal activity against all the tested bacteria particularly against the Staphylococcus strains when tested in the ionic environment of tears. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2. Interestingly, lysozyme purified from dromedary tears showed a significant bactericidal activity against Listeria monocytogene and Staphylococcus epidermidis, whereas the one purified from human tears displayed no activity against these two strains. We have also demonstrated that Ca(2+) is crucial for the activity of dromedary tear sPLA2 and to a less extent Mg(2+) ions. Given the presence of sPLA2 in tears and intestinal secretions, this enzyme may play a substantial role in innate mucosal and systemic bactericidal defenses against Gram-positive bacteria. PMID:23344945

Ben Bacha, Abir; Abid, Islem

2013-03-01

147

Acquired inducible antimicrobial resistance in Gram-positive bacteria  

PubMed Central

A major contributor to the emergence of antibiotic resistance in Gram-positive bacterial pathogens is the expansion of acquired, inducible genetic elements. Although acquired, inducible antibiotic resistance is not new, the interest in its molecular basis has been accelerated by the widening distribution and often ‘silent’ spread of the elements responsible, the diagnostic challenges of such resistance and the mounting limitations of available agents to treat Gram-positive infections. Acquired, inducible antibiotic resistance elements belong to the accessory genome of a species and are horizontally acquired by transformation/recombination or through the transfer of mobile DNA elements. The two key, but mechanistically very different, induction mechanisms are: ribosome-sensed induction, characteristic of the macrolide–lincosamide–streptogramin B antibiotics and tetracycline resistance, leading to ribosomal modifications or efflux pump activation; and resistance by cell surface-associated sensing of ?-lactams (e.g., oxacillin), glycopeptides (e.g., vancomycin) and the polypeptide bacitracin, leading to drug inactivation or resistance due to cell wall alterations.

Chancey, Scott T; Zahner, Dorothea; Stephens, David S

2012-01-01

148

Regulation of innate and adaptive immune responses by Gram-positive and Gram-negative bacteria  

Microsoft Academic Search

Bacteria are classified as Gram-positive or Gram-negative, depending on their cell wall structure. The role of the bacterial cell wall in immune regulation is the focus of the current work. Most Gram-positive bacteria stimulate monocytes to produce large amounts of IL-12. IL-12 induces production of IFN-? in T cells and NK cells, which, in turn, activates the bactericidal capacity of

Anna Martner

149

Butirosin, a New Aminoglycosidic Antibiotic Complex: Antibacterial Activity In Vitro and in Mice  

PubMed Central

Butirosin is a new aminoglycosidic antibiotic complex which has broad gram-negative and gram-positive inhibitory antibacterial activity, as well as some bactericidal properties. Significantly susceptible bacteria include strains of Staphylococcus aureus and Streptococcus pyogenes, and pathogenic gram-negative species such as Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and P. vulgaris, Salmonella enteritidis and S. typhimurium, Shigella flexneri and S. sonnei. Good activity by parenteral dosing was obtained in various acute mouse infections. Butirosin is especially interesting because of its activity against Pseudomonas aeruginosa in vitro, including gentamicin-resistant clinical isolates, and in experimental mouse infections at relatively low doses.

Heifetz, C. L.; Fisher, M. W.; Chodubski, J. A.; DeCarlo, M. O'.

1972-01-01

150

Human Defensin 5 Disulfide Array Mutants: Disulfide Bond Deletion Attenuates Antibacterial Activity Against Staphylococcus aureus  

PubMed Central

Human ?-defensin 5 (HD5, HD5ox to specify the oxidized and disulfide linked form) is a 32-residue cysteine-rich host-defense peptide, expressed and released by small intestinal Paneth cells, that exhibits antibacterial activity against a number of Gram-negative and –positive bacterial strains. To ascertain the contributions of its disulfide array to structure, antimicrobial activity, and proteolytic stability, a series of HD5 double mutant peptides where pairs of cysteine residues corresponding to native disulfide linkages (Cys3—Cys31, Cys5—Cys20, Cys10—Cys30) were mutated to Ser or Ala residues were overexpressed in E. coli, purified and characterized. A hexa mutant peptide, HD5[Serhexa], where all six native Cys residues are replaced by Ser residues was also evaluated. Removal of a single native S—S linkage influences oxidative folding and regioisomerization, antibacterial activity, Gram-negative bacterial membrane permeabilization, and proteolytic stability. Whereas the majority of the HD5 mutant peptides show low-micromolar activity against Gram-negative E. coli ATCC 25922 in colony counting assays, the wild-type disulfide array is essential for low-micromolar activity against Gram-positive S. aureus ATCC 25923. Removal of a single disulfide bond attenuates the activity observed for HD5ox against this Gram-positive bacterial strain. This observation supports the notion that the HD5ox mechanism of antibacterial action differs for Gram-negative and Gram-positive species (Wei, G.; de Leeuw, E., Pazgier, M., Yuan, W., Zou, G., Wang, J., Ericksen, B., Lu, W.-Y.; Lehrer, R. I.; Lu, W. (2009) J. Biol. Chem. 284, 29180-29192), and that the native disulfide array is a requirement for its activity against S. aureus.

Wanniarachchi, Yoshitha A.; Kaczmarek, Piotr; Wan, Andrea; Nolan, Elizabeth M.

2011-01-01

151

Antibacterial activity of some selected medicinal plants of Pakistan  

PubMed Central

Background Screening of the ethnobotenical plants is a pre-requisite to evaluate their therapeutic potential and it can lead to the isolation of new bioactive compounds. Methods The crude extracts and fractions of six medicinal important plants (Arisaema flavum, Debregeasia salicifolia, Carissa opaca, Pistacia integerrima, Aesculus indica, and Toona ciliata) were tested against three Gram positive and two Gram negative ATCC bacterial species using the agar well diffusion method. Results The crude extract of P. integerrima and A. indica were active against all tested bacterial strains (12-23 mm zone of inhibition). Other four plant's crude extracts (Arisaema flavum, Debregeasia salicifolia, Carissa opaca, and Toona ciliata) were active against different bacterial strains. The crude extracts showed varying level of bactericidal activity. The aqueous fractions of A. indica and P. integerrima crude extract showed maximum activity (19.66 and 16 mm, respectively) against B. subtilis, while the chloroform fractions of T. ciliata and D. salicifolia presented good antibacterial activities (13-17 mm zone of inhibition) against all the bacterial cultures tested. Conclusion The methanol fraction of Pistacia integerrima, chloroform fractions of Debregeasia salicifolia &Toona ciliata and aqueous fraction of Aesculus indica are suitable candidates for the development of novel antibacterial compounds.

2011-01-01

152

Traditional medicine in north Côte-d'Ivoire: screening of 50 medicinal plants for antibacterial activity.  

PubMed

Sixty-seven crude ethanol extracts from 50 plants (31 families), which are used in North Côte-d'Ivoire as traditional remedies for bacterial diseases, were screened for in vitro activity against Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes and Bacillus subtilis) bacteria. Thirty-one extracts showed antibacterial activity only on Gram positive bacteria. Of these, 10 extracts from 10 plant species had a promising level of activity against bacteria including strains resistant to antibiotics such as aminosides, penicillin M, macrolides, lincosamide and streptrogramin B. The most active was Erythrina senegalensis DC (Fabaceae) followed by Bobgunnia madagascariensis (Desv.) J.H. Kirkbr. & Wiersema (Caesalpinaceae), Waltheria lanceolata R. Br. ex Mast. (Sterculiaceae), Uapaca togoensis Pax. (Euphorbiaceae), Ximenia americana L. (Olacaceae), Khaya senegalensis (Ders.) A. Juss. (Meliaceae), Lannea acida A. Rich. (Anacardiaceae), Cissus populnea Guill. & Perr. (Vitaceae), Keetia hispida (Benth.) Bridson (Rubiaceae) and Ficus thonningii (Miq.) A. Rich. (Moraceae). This is the first report of the antibacterial potency of these 10 plant species on a range of bacteria. The results provided evidence that some of the studied plants might indeed be potential sources of new antibacterial agents, also against some antibiotic-resistant strains. PMID:15182903

Koné, W M; Atindehou, K Kamanzi; Terreaux, C; Hostettmann, K; Traoré, D; Dosso, M

2004-07-01

153

Antibacterial activity of chitosan-based matrices on oral pathogens.  

PubMed

Chitosan is a well sought-after polysaccharide in biomedical applications due to its biocompatibility, biodegradability to non-toxic substances, and ease of fabrication into various configurations. However, alterations in the anti-bacterial properties of chitosan in various forms is not completely understood. The objective of this study was to evaluate the anti-bacterial properties of chitosan matrices in different configurations against two pathogens-Gram-positive Streptococcus mutans and Gram-negative Actinobacillus actinomycetemcomitans. Two-dimensional (2-D) membranes and three-dimensional (3-D) porous scaffolds were synthesized by air drying and controlled-rate freeze drying. Matrices were suspended in bacterial broths with or without lysozyme (enzyme that degrades chitosan). Influences of pore size, blending with Polycaprolactone (PCL, a synthetic polymer), and neutralization process on bacterial proliferation were studied. Transient changes in optical density of the broth, adhesion characteristics, viability, and contact-dependent bacterial activity were assessed. 3-D porous scaffolds were more effective in reducing the proliferation of S. mutans in suspension than 2-D membranes. However, no significant differences were observed on the proliferation of A. actinomycetemcomitans. Presence of lysozyme significantly increased the antibacterial activity of chitosan against A. actinomycetemcomitans. Pore size did not affect the proliferation kinetics of either species, with or without lysozyme. NaOH neutralization of chitosan increased bacterial adhesion whereas ethanol neutralization inhibited adhesion without lowering proliferation. Mat culture tests indicated that chitosan does not allow proliferation on its surface and it loses antibacterial activity upon blending with PCL. Results suggest that the chemical and structural characteristics of chitosan-based matrices can be manipulated to influence the interaction of different bacterial species. PMID:17701312

Sarasam, Aparna R; Brown, Phoebe; Khajotia, Sharukh S; Dmytryk, John J; Madihally, Sundararajan V

2008-03-01

154

Evaluation of the VITEK 2 gram positive (GP) microbial identification test card: collaborative study.  

PubMed

A collaborative study was conducted to evaluate the performance of the VITEK 2 Gram Positive (GP) identification card for use with the VITEK 2 automated microbial identification system. The GP test card is used in the identification of selected Gram positive organisms, including Listeria and Staphylococcus species. The VITEK 2 GP card is based on 43 biochemical tests measuring carbon source utilization, inhibition and resistance, and enzymatic activities. A total of 20 laboratories representing government, industry, and private testing laboratories throughout the United States participated. In this study, 720 Gram-positive inclusivity isolates were analyzed by the GP Identification method. Of the 720 well-characterized isolates, 714 were identified correctly, zero were misidentified, zero were unidentified, and six were not characterized as a Gram-positive organism by the VITEK 2 GP method. Additionally, 120 strains exclusive of Gram-positive organisms were screened by Gram stain. A total of 106 isolates were correctly excluded. Fourteen organisms were incorrectly characterized by Gram stain procedures, thus resulting in improper analysis and misidentification by VITEK GP. The VITEK 2 GP identification method is an acceptable automated method for the rapid identification of selected Gram-positive bacteria. PMID:23175976

Crowley, Erin; Bird, Patrick; Fisher, Kiel; Goetz, Katherine; Boyle, Megan; Benzinger, M Joseph; Juenger, Marc; Agin, James; Goins, David; Johnson, Ronald L

2012-01-01

155

Antibacterial activities and phytochemical analysis of Cassia fistula (Linn.) leaf.  

PubMed

Cassia fistula Linn. which belongs to family Leguminosae is a medium-sized tree and its different parts are used in ayurvedic medicine as well as home remedies for common ailments. Sequential extraction was carried out using solvents viz. petroleum ether, chloroform, ethanol, methanol and water from leaf of the plant were investigated for preliminary phytochemical and antibacterial property. Results of the study showed that all the extracts had good inhibitory activity against Gram-positive test organism. Although all five extracts showed promising antibacterial activity against test bacterial species, yet maximum activity was observed in ethanol extract. The minimum inhibitory concentration ranged in between 94 to 1 500 ?g/ml. Evaluation of phytochemicals such as alkaloids, flavonoids, carbohydrates, glycosides, protein and amino acids, saponins, and triterpenoids revealed the presence of most of constituents in polar extracts (ethanol, methanol, and aqueous) compared with nonpolar extracts (petroleum ether and chloroform). Furthermore, the ethanol extract was subjected to TLC bioautography and time-kill study against Staphylococcus epidermidis. All the findings exhibit that the leaf extracts have broad-spectrum activity and suggest its possible use in treatment of infectious diseases. PMID:22171295

Panda, Sujogya K; Padhi, L P; Mohanty, G

2011-01-01

156

Antibacterial activities and phytochemical analysis of Cassia fistula (Linn.) leaf  

PubMed Central

Cassia fistula Linn. which belongs to family Leguminosae is a medium-sized tree and its different parts are used in ayurvedic medicine as well as home remedies for common ailments. Sequential extraction was carried out using solvents viz. petroleum ether, chloroform, ethanol, methanol and water from leaf of the plant were investigated for preliminary phytochemical and antibacterial property. Results of the study showed that all the extracts had good inhibitory activity against Gram-positive test organism. Although all five extracts showed promising antibacterial activity against test bacterial species, yet maximum activity was observed in ethanol extract. The minimum inhibitory concentration ranged in between 94 to 1 500 ?g/ml. Evaluation of phytochemicals such as alkaloids, flavonoids, carbohydrates, glycosides, protein and amino acids, saponins, and triterpenoids revealed the presence of most of constituents in polar extracts (ethanol, methanol, and aqueous) compared with nonpolar extracts (petroleum ether and chloroform). Furthermore, the ethanol extract was subjected to TLC bioautography and time-kill study against Staphylococcus epidermidis. All the findings exhibit that the leaf extracts have broad-spectrum activity and suggest its possible use in treatment of infectious diseases.

Panda, Sujogya K.; Padhi, L. P.; Mohanty, G.

2011-01-01

157

Combination of Pantothenamides with Vanin Inhibitors as a Novel Antibiotic Strategy against Gram-Positive Bacteria  

PubMed Central

The emergence of resistance against current antibiotics calls for the development of new compounds to treat infectious diseases. Synthetic pantothenamides are pantothenate analogs that possess broad-spectrum antibacterial activity in vitro in minimal media. Pantothenamides were shown to be substrates of the bacterial coenzyme A (CoA) biosynthetic pathway, causing cellular CoA depletion and interference with fatty acid synthesis. In spite of their potential use and selectivity for bacterial metabolic routes, these compounds have never made it to the clinic. In the present study, we show that pantothenamides are not active as antibiotics in the presence of serum, and we found that they were hydrolyzed by ubiquitous pantetheinases of the vanin family. To address this further, we synthesized a series of pantetheinase inhibitors based on a pantothenate scaffold that inhibited serum pantetheinase activity in the nanomolar range. Mass spectrometric analysis showed that addition of these pantetheinase inhibitors prevented hydrolysis of pantothenamides by serum. We found that combinations of these novel pantetheinase inhibitors and prototypic pantothenamides like N5-Pan and N7-Pan exerted antimicrobial activity in vitro, particularly against Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Streptococcus pyogenes) even in the presence of serum. These results indicate that pantothenamides, when protected against degradation by host pantetheinases, are potentially useful antimicrobial agents.

Jansen, Patrick A. M.; Hermkens, Pedro H. H.; Zeeuwen, Patrick L. J. M.; Botman, Peter N. M.; Blaauw, Richard H.; Burghout, Peter; van Galen, Peter M.; Mouton, Johan W.; Rutjes, Floris P. J. T.

2013-01-01

158

In vitro and in vivo antibacterial activities of E1077, a novel parenteral cephalosporin.  

PubMed Central

E1077, a new injectable cephalosporin with a broad antibacterial spectrum and potent antibacterial activity, was evaluated for its in vitro and in vivo antibacterial activities in comparison with those of cefpirome, cefuzonam, ceftazidime, and cefotaxime. E1077 showed broad in vitro antibacterial activity against gram-positive and gram-negative bacteria. Against methicillin-susceptible Staphylococcus aureus, E1077 was as active as cefpirome; the MIC for 90% of strains tested (MIC90) was 1.0 microgram/ml. Against methicillin-resistant S. aureus, E1077 was less active (MIC90, 64 micrograms/ml). For Enterobacter cloacae and Pseudomonas aeruginosa, E1077 was fourfold more active than cefpirome, with MIC90s of 1.0 and 16 micrograms/ml, respectively. For Proteus vulgaris, the MIC90 of E1077 was 32 micrograms/ml, which was fourfold greater than that of cefpirome. Against other gram-negative strains tested, the in vitro activity of E1077 was comparable to that of cefpirome. The broad antibacterial spectrum of E1077 was reflected by its in vivo efficacy against experimental septicemia caused by gram-positive and gram-negative bacteria. Against S. aureus 90 and P. aeruginosa E7, E1077 had activity superior to those of the reference compounds; against most other bacterial strains, the efficacy of E1077 was similar to that of cefpirome. Levels of E1077 in plasma and tissue of mice were studied. At 15 min after a single subcutaneous administration, E1077 displayed high peak levels (mean, 31.8 +/- 3.1 micrograms/ml). These results indicate that the in vitro and in vivo efficacies of E1077 are similar to those of cefpirome except against P. aeruginosa and P. vulgaris.

Toyosawa, T; Miyazaki, S; Tsuji, A; Yamaguchi, K; Goto, S

1993-01-01

159

Chemical composition and antibacterial activity of the essential oil of Retrohpyllum rospigliosii fruits from Colombia.  

PubMed

The essential oil from fruits of Retrophyllum rospigliosii (Pilger) C.N. Page grown in Colombia was analyzed by GC and GC/MS. Ninety-one compounds were identified, of which the most prominent were limonene (37.7%) and alpha-pinene (16.3%). The in vitro antibacterial activity of the essential oil was studied against seven bacterial strains using the disc diffusion method. The strongest activity of the oil was against the Gram-positive bacterium Bacillus cereus. PMID:20734957

Quijano-Celis, Clara E; Gaviria, Mauricio; Consuelo, Vanegas-López; Ontiveros, Ina; Echeverri, Leonardo; Morales, Gustavo; Pino, Jorge A

2010-07-01

160

Antibacterial Activity of New Dibenzoxepinone Oximes with Fluorine and Trifluoromethyl Group Substituents  

PubMed Central

In this paper we present the antimicrobial activity of some newly synthesized dibenz[b,e]oxepin derivatives bearing the oximino moiety, and fluorine (F) and trifluoromethyl (CF3) group substituents. The chemical structure and purity of the new compounds were assessed by using elemental analysis, NMR and FTIR spectroscopy. The new compounds were screened for their antibacterial activity towards Gram-positive and Gram-negative strains, by qualitative and quantitative assays. Our results demonstrated that the CF3 and F disubstituted compounds could be considered for the further development of novel antimicrobial drugs.

Limban, Carmen; Chifiriuc, Mariana Carmen

2011-01-01

161

Antibacterial and antifungal activity of a soda-lime glass containing copper nanoparticles.  

PubMed

A low melting point soda-lime glass powder containing copper nanoparticles with high antibacterial (against gram-positive and gram-negative bacteria) and antifungal activity has been obtained. Sepiolite fibres containing monodispersed copper nanoparticles (d(50) approximately 30 +/- 5 nm) were used as the source of the copper nanoparticles. The observed high activity of the obtained glass powder, particularly against yeast, has been explained by considering the inhibitory synergistic effect of the Ca(2+) lixiviated from the glass on the growth of the colonies. PMID:19907067

Esteban-Tejeda, L; Malpartida, F; Esteban-Cubillo, A; Pecharromán, C; Moya, J S

2009-12-16

162

Antibacterial and antifungal activity of a soda-lime glass containing copper nanoparticles  

NASA Astrophysics Data System (ADS)

A low melting point soda-lime glass powder containing copper nanoparticles with high antibacterial (against gram-positive and gram-negative bacteria) and antifungal activity has been obtained. Sepiolite fibres containing monodispersed copper nanoparticles (d50?30 ± 5 nm) were used as the source of the copper nanoparticles. The observed high activity of the obtained glass powder, particularly against yeast, has been explained by considering the inhibitory synergistic effect of the Ca2+ lixiviated from the glass on the growth of the colonies.

Esteban-Tejeda, L.; Malpartida, F.; Esteban-Cubillo, A.; Pecharromán, C.; Moya, J. S.

2009-12-01

163

Identification and characterization of UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from the Gram-positive pathogen Streptococcus pneumoniae.  

PubMed Central

The UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from a Gram-positive pathogen, Streptococcus pneumoniae, was identified and characterized. The enzyme from S. pneumoniae shows 31% identity with the MurB protein from Escherichia coli, and contains the catalytic residues, substrate-binding residues and FAD-binding motif identified previously in the E. coli protein. The gene was cloned into the pET28a+ expression vector, and the 34.5 kDa protein that it encodes was overexpressed in E. coli strain BL21(DE3) to 30% of total cell protein. The majority of the protein was found to be insoluble. A variety of methods were used to increase the amount of soluble protein to 10%. This was then purified to near homogeneity in a two-step process. The absorption spectrum of the purified protein indicated it to be a flavoprotein, like its E. coli homologue, with a characteristic absorption at 463 nm. The enzyme was shown to be active, reducing UDP-N-acetylglucosamine enolpyruvate with the concomitant oxidation of NADPH, and was characterized kinetically with respect to its two substrates. The enzyme showed properties similar to those of its E. coli counterpart, being activated by univalent cations and being subject to substrate inhibition. The characterization of an important cell wall biosynthesis enzyme from a Gram-positive pathogen provides a good starting point for the discovery of antibacterial agents against MurB.

Sylvester, D R; Alvarez, E; Patel, A; Ratnam, K; Kallender, H; Wallis, N G

2001-01-01

164

Plants used in Guatemala for the treatment of respiratory diseases. 1. Screening of 68 plants against gram-positive bacteria.  

PubMed

Respiratory ailments are important causes of morbidity and mortality in developing countries. Ethnobotanical surveys and literature reviews conducted in Guatemala during 1986-88 showed that 234 plants from 75 families, most of them of American origin, have been used for the treatment of respiratory ailments. Three Gram-positive bacteria causing respiratory infections (Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes) were used to screen 68 of the most commonly used plants for activity. Twenty-eight of these (41.2%) inhibited the growth of one or more of the bacteria tested. Staphylococcus aureus was inhibited by 18 of the plant extracts, while 7 extracts were effective against Streptococcus pyogenes. Plants of American origin which exhibited antibacterial activity were: Gnaphalium viscosum, Lippia alba, Lippia dulcis, Physalis philadelphica, Satureja brownei, Solanum nigrescens and Tagetes lucida. These preliminary in vitro results provide scientific basis for the use of these plants against bacterial respiratory infections. PMID:2023428

Caceres, A; Alvarez, A V; Ovando, A E; Samayoa, B E

1991-02-01

165

In vitro and in vivo antibacterial activities of E1077, a novel parenteral cephalosporin with a broad antibacterial spectrum.  

PubMed Central

E1077 is a new injectable cephalosporin with a broad spectrum of antibacterial activity against gram-positive and gram-negative bacteria, including staphylococci and Pseudomonas aeruginosa. The in vitro activities of E1077 against clinical isolates of methicillin-susceptible Staphylococcus aureus (MIC of E1077 for 90% of the strains tested [MIC90], 0.78 microgram/ml) and methicillin-resistant S. aureus (MIC90, 50 micrograms/ml) were similar to those of cefpirome and flomoxef. Against Enterococcus faecalis (MIC90, 6.25 micrograms/ml), E1077 was the most active of the drugs tested and four times more active than cefpirome. The MIC90S of E1077 for streptococci, Haemophilus influenzae, and Neisseria gonorrhoeae ranged from 0.05 to 0.78 microgram/ml; E1077 was similar in activity to cefpirome. E1077 inhibited 90% of most species of the family Enterobacteriaceae at concentrations of less than or equal to 1.56 micrograms/ml, with the exception of Serratia marcescens and Proteus vulgaris (12.5 micrograms/ml). The activity of E1077 against P. aeruginosa (MIC90, 6.25 micrograms/ml) was comparable to that of ceftazidime. In vivo activity was evaluated with systemic infections in mice. E1077 showed a protective effect against systemic infections by gram-positive or gram-negative bacteria, as reflected by its in vitro activity. The protective effects of E1077 were higher than those of cefpirome against S. aureus and P. aeruginosa infections and similar to those of cefpirome against other bacterial infections. Morphological studies using differential interference and phase-contrast microscopy showed that low concentrations of E1077 caused swelling of S. aureus and spheroplast and bulge formation in P. aeruginosa. In general, the antibacterial profile of E1077 is similar to that of cefpirome. Images

Hata, K; Otsuki, M; Nishino, T

1992-01-01

166

Phytochemical screening, cytotoxicity and antibacterial activities of two Bangladeshi medicinal plants.  

PubMed

The objectives of the present study were to investigate phytochemical screening and to assay cytotoxicity and antibacterial activities of ethanolic extracts of leaves of two medicinal plants, Aglaonema hookerianum Schott (Family: Araceae) and Lannea grandis Engl. (Family: Anacardiaceae) available in Bangladesh. The brine shrimp lethality bioassay showed that the ethanolic extracts of Aglaonema hookerianum and Lannea grandis possessed cytotoxic activities with LC50 5.25 (microg mL(-1)) and 5.75 (microg mL(-1)) and LC90 10.47 (microg mL(-1)) and 9.55 (microg mL(-1)), respectively. Two extracts obtained from leaves were examined for their antibacterial activities against some gram positive bacteria such as Bacillus subtilis, Bacillus megaterium and Staphylococcus aureus, also gram negative strains of Pseudomonas aeruginosa, Escherichia coli, Shigella dysenteriae, Salmonella typhi, Salmonella paratyphi and Vibrio cholerae. Agar disc diffusion method was applied to observe the antibacterial efficacy of the extracts. Results indicated that both plant extracts (500 microg disc(-1)) displayed antibacterial activity against all of the tested microorganisms. These results were also compared with the zones of inhibition produced by commercially available standard antibiotic, Amoxicillin at concentration of 10 microg disc(-1). Observed antibacterial properties of the ethanolic extract of Aglaonema hookerianum Schott and Lannea grandis Engl. showed that both plants might be useful sources for the development of new potent antibacterial agents. PMID:22518935

Roy, Ajoy; Biswas, Subrata Kumar; Chowdhury, Anusua; Shill, Manik Chandra; Raihan, Sheikh Zahir; Muhit, Md Abdul

2011-10-01

167

Physicochemical Properties That Enhance Discriminative Antibacterial Activity of Short Dermaseptin Derivatives  

PubMed Central

Antimicrobial peptides are widely believed to exert their effects by nonspecific mechanisms. We assessed the extent to which physicochemical properties can be exploited to promote discriminative activity by manipulating the N-terminal sequence of the 13-mer dermaseptin derivative K4-S4(1-13) (P). Inhibitory activity determined in culture media against 16 strains of bacteria showed that when its hydrophobicity and charge were changed, P became predominantly active against either gram-positive or gram-negative bacteria. Thus, conjugation of various aminoacyl-lysin moieties (e.g., aminohexyl-K-P) led to inactivity against gram-positive bacteria (MIC50 > 50 ?M) but potent activity against gram-negative bacteria (MIC50, 6.2 ?M). Conversely, conjugation of equivalent acyls to the substituted analog M4-S4(1-13) (e.g., hexyl-M4-P) led to inactivity against gram-negative bacteria (MIC50 > 50 ?M) but potent activity against gram-positive bacteria (MIC50, 3.1 ?M). Surface plasmon resonance experiments, used to investigate peptides' binding properties to lipopolysaccharide-containing idealized phospholipid membranes, suggest that although the acylated derivatives have increased lipophilic properties with parallel antibacterial behavior, hydrophobic derivatives are prevented from reaching the cytoplasmic membranes of gram-negative bacteria. Moreover, unlike modifications that enhanced the activity against gram-positive bacteria, which also enhanced hemolysis, we found that modifications that enhanced activity against gram-negative bacteria generally reduced hemolysis. Thus, compared with the clinically tested peptides MSI-78 and IB-367, the dermaseptin derivative aminohexyl-K-P performed similarly in terms of potency and bactericidal kinetics but was significantly more selective in terms of discrimination between bacteria and human erythrocytes. Overall, the data suggest that similar strategies maybe useful to derive potent and safe compounds from known antimicrobial peptides.

Rotem, Shahar; Radzishevsky, Inna; Mor, Amram

2006-01-01

168

Synthesis, characterization, and antibacterial activity of transition metal complexes with 5-hydroxy-7,4'-dimethoxyflavone.  

PubMed

Complexes of CuII, NiII, CoII, ZnII, FeIII, CrIII, CdII, and MnII with the natural product 5-hydroxy-7,4'-dimethoxyflavone have been synthesized and the probable structures of these complexes have been proposed on the basis of elemental analyses, molecular weight determination, magnetic moments, and electronic and IR spectral data. The presence of coordinated and crystal water molecules was demonstrated by thermal studies. The antibacterial activity of the ligand and all the complexes has been determined on gram positive and gram negative bacteria. PMID:1402876

Wang, S X; Zhang, F J; Feng, Q P; Li, Y L

1992-06-01

169

Chemical composition and antibacterial activity of essential oils from Thymus spinulosus Ten. (Lamiaceae).  

PubMed

The chemical composition of essential oils from aerial parts of Thymus spinulosus Ten. (Lamiaceae) is reported. Four oils from plants growing in different environmental conditions were characterized by GC and GC-MS methods; the oils seem to indicate a new chemotype in the genus Thymus. Influences of soil and altitude characteristics on the essential oil composition are discussed. The oils showed antibacterial activity against Gram-positive (Staphylococcus aureus, Streptococcus faecalis, Bacillus subtilis, and Bacillus cereus) and Gram-negative (Proteus mirabilis, Escherichia coli, Salmonella typhimuium Ty2, and Pseudomonas aeruginosa) bacteria. PMID:12797754

De Feo, Vincenzo; Bruno, Maurizio; Tahiri, Bochra; Napolitano, Francesco; Senatore, Felice

2003-06-18

170

Preparation, characterization, and antibacterial activity studies of silver-loaded poly(styrene-co-acrylic acid) nanocomposites.  

PubMed

A simple method for preparing a new type of stable antibacterial agent was presented. Monodisperse poly(styrene-co-acrylic acid) (PSA) nanospheres, serving as matrices, were synthesized via soap-free emulsion polymerization. Field-emission scanning electron microscopy micrographs indicated that PSA nanospheres have interesting surface microstructures and well-controlled particle size distributions. Silver-loaded poly(styrene-co-acrylic acid) (PSA/Ag-NPs) nanocomposites were prepared in situ through interfacial reduction of silver nitrate with sodium borohydride, and further characterized by transmission electron microscopy and X-ray diffraction. Their effects on antibacterial activity including inhibition zone, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bactericidal kinetics were evaluated. In the tests, PSA/Ag-NPs nanocomposites showed excellent antibacterial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. These nanocomposites are considered to have potential application in antibacterial coatings on biomedical devices to reduce nosocomial infection rates. PMID:24433897

Song, Cunfeng; Chang, Ying; Cheng, Ling; Xu, Yiting; Chen, Xiaoling; Zhang, Long; Zhong, Lina; Dai, Lizong

2014-03-01

171

Antibacterial Activity of Mother Tinctures of Cholistan Desert Plants in Pakistan  

PubMed Central

The mother tinctures of desert were screened for antibacterial activity against bacterial strains of Gram-positive and Gram-negative bacteria. Mother tinctures were prepared by maceration process and antibacterial activity of different plants was evaluated and compared by measuring their zones of inhibition. The results indicated that Boerrhavia diffusa mother tincture had excellent activity only against Escherichia coli. Mother tincture of Chorozophora plicata showed highly effective results against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa whereas Echinops echinatus mother tincture showed highly effectiveness only against Salmonella typhi. Heliotropium europaeum mother tincture exhibited highly effective results against Bacillus subtilis in all concentrations. Tamrix aphylla presented maximum activity only against Bacillus subtilis in all three concentrations. Among the selected species Heliotropium europaeum, Chorozophora plicata and Tamrix aphylla were more effective plants against many microorganisms. However, Boerrhavia diffusa and Echinops echinatus were less effective plants against tested pathogenic bacteria.

Ahmad, M.; Ghafoor, Nazia; Aamir, M. N.

2012-01-01

172

Mycosynthesis: antibacterial, antioxidant and antiproliferative activities of silver nanoparticles synthesized from Inonotus obliquus (Chaga mushroom) extract.  

PubMed

In the present study, silver nanoparticles (AgNPs) were rapidly synthesized from silver nitrate solution at room temperature using Inonotus obliquus extract. The mycogenic synthesized AgNPs were characterized by UV-Visible absorption spectroscopy, Fourier transform infrared (FTIR), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). SEM revealed mostly spherical nanoparticles ranging from 14.7 to 35.2nm in size. All AgNPs concentrations showed good ABT radical scavenging activity. Further, AgNPs showed effective antibacterial activity against both gram negative and gram positive bacteria and antiproliferative activity toward A549 human lung cancer (CCL-185) and MCF-7 human breast cancer (HTB-22) cell lines. The samples demonstrated considerably high antibacterial, and antiproliferative activities against bacterial strains and cell lines. PMID:24380885

Nagajyothi, P C; Sreekanth, T V M; Lee, Jae-il; Lee, Kap Duk

2014-01-01

173

Synthesis and antibacterial activities of N-substituted-glycinyl 1H-1,2,3-triazolyl oxazolidinones.  

PubMed

A series of 1H-1,2,3-triazolyl piperazino oxazolidinone analogs with optionally varied glycinyl substitutions were synthesized and their antibacterial activity assessed against a panel of susceptible and resistant Gram-positive and selected Gram-negative bacteria including clinical isolates. The N-aroyl- and N-heteroaroyl-glycinyl (MIC: 0.06-4 ?g/ml) derivatives were more potent than the N-acylglycinyl (2-8 ?g/ml) derivatives against all Gram-positive bacteria tested. Nitro substitution on aryl and heteroaryl rings significantly enhanced activity against Gram-positive bacteria, as noted with the 3,5-dinitrobenzoyl (6m and 6n) and 5-nitro-2-furoyl (6u and 6v) derivatives with MIC ranges of and 0.25-0.5 and 0.06-0.5 ?g/ml, respectively. These nitro analogs also showed more potent extended activity against Moraxella catarrhalis, with MICs ranges of 0.25-1 ?g/ml, compared to linezolid (MIC: 8 ?g/ml). Hence, the presence of the N-aroyl and/or N-heteroaroyl glycinyl structural motifs as spacer group could significantly enhance the antibacterial activities of 1H-1,2,3-triazolyl oxazolidinone class of compounds. PMID:23811087

Phillips, Oludotun A; Udo, Edet E; Abdel-Hamid, Mohammed E; Varghese, Reny

2013-08-01

174

Chocolate agar, a differential medium for gram-positive cocci.  

PubMed Central

Reactions incurred on chocolate agar by gram-positive cocci were correlated with species identity. Darkening and clearing of the medium was usually associated with the species Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus simulans, and Streptococcus faecalis. Yellowing of chocolate agar was associated with alpha-hemolytic species of Streptococcus. The study demonstrated that reactions occurring on chocolate agar are useful in identifying gram-positive cocci.

Gunn, B A

1984-01-01

175

Moderately halophilic gram-positive bacterial diversity in hypersaline environments  

Microsoft Academic Search

Moderately halophilic bacteria are microorganisms that grow optimally in media containing 3%–15% (w\\/v) salt. They are represented\\u000a by a heterogeneous group of microorganisms included in many different genera. Gram-negative moderately halophilic bacteria\\u000a have been studied in more detail, but studies on gram-positive species are more scarce. Recent studies carried out by our\\u000a research group on gram-positive moderate halophiles have permitted

Antonio Ventosa; M. Carmen Márquez; María J. Garabito; David R. Arahal

1998-01-01

176

Screening of antibacterial activity of Amaicha del Valle (Tucumán, Argentina) propolis.  

PubMed

Propolis is extensively used in Argentine folk medicine. Alcoholic extracts of propolis from four localities of Amaicha del Valle (El Paraiso, La Banda Este, La Banda Oeste and El Molino), Province of Tucumán and from Cerrillos, Province of Santiago del Estero, Argentina were prepared. All showed antibacterial activity against Gram positive bacteria, the propolis from La Banda Este being the most active (MIC = 7.8 microg/ml) against Streptococcus piogenes, an antibiotic resistant bacterium. Thin layer chromatographic (TLC) separation profiles of propolis from Amaicha del Valle region were similar but differ from the alcoholic extract of the propolis from Cerrillos, another phytogeographical region of Argentina (provincia chaqueña). Bioautographic assays of the TLC profiles showed that several separated compounds of the Amaicha del Valle propolis have antibacterial activity. The difference in composition between Amaicha del Valle and Cerrillos propolis coincides with a different phytogeographical formation. PMID:10624867

Nieva Moreno, M I; Isla, M I; Cudmani, N G; Vattuone, M A; Sampietro, A R

1999-12-15

177

Antibacterial activity of baking soda.  

PubMed

The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque. PMID:12017929

Drake, D

1997-01-01

178

Antibacterial activity of baking soda.  

PubMed

The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque. PMID:11524862

Drake, D

1996-01-01

179

Clinical update on linezolid in the treatment of Gram-positive bacterial infections  

PubMed Central

Gram-positive pathogens are a significant cause of morbidity and mortality in both community and health care settings. Glycopeptides have traditionally been the antibiotics of choice for multiresistant Gram-positive pathogens but there are problems with their use, including the emergence of glycopeptide-resistant strains, tissue penetration, and achieving and monitoring adequate serum levels. Newer antibiotics such as linezolid, a synthetic oxazolidinone, are available for the treatment of resistant Gram-positive bacteria. Linezolid is active against a wide range of Gram-positive bacteria and has been generally available for the treatment of Gram-positive infections since 2000. There are potential problems with linezolid use, including its bacteriostatic action and the relatively high incidence of reported adverse effects, particularly with long-term use. Long-term use may also be complicated by the development of resistance. However, linezolid has been shown to be clinically useful in the treatment of several serious infections where traditionally bacteriocidal agents have been required and many of its adverse effects are reversible on cessation. It has also been shown to be a cost-effective treatment option in several studies, with its high oral bioavailability allowing an early change from intravenous to oral formulations with consequent earlier patient discharge and lower inpatient costs.

Ager, Sally; Gould, Kate

2012-01-01

180

Telavancin: a new lipoglycopeptide for gram-positive infections.  

PubMed

Telavancin is a lipoglycopeptide derivative of vancomycin. Similar to vancomycin, it demonstrates activity in vitro against a variety of Gram-positive pathogens, including but not limited to methicillin-resistant Staphylococccus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae (PRSP). Modifications to vancomycin's structure expanded telavancin's spectrum of activity in vitro to include organisms such as glycopeptide-intermediate S. aureus (GISA), vancomycin-resistant S. aureus (VRSA) and vancomycin-resistant enterococci (VRE). However, the clinical implications of this are currently unknown. Similar to other glycopeptides, televancin binds to the D-alanyl-D-alanine (D-Ala-D-Ala) terminus in Gram-positive organisms, resulting in inhibition of bacterial cell wall synthesis. In addition, telavancin causes depolarization of the bacterial cell membrane and increased membrane permeability. The resulting activity in vitro is rapidly bactericidal and concentration dependent, with the ratio of area under the time concentration curve to minimum inhibitory concentration (AUC/MIC) as the best predictor of activity in animal models to date. In humans, telavancin exhibits a pharmacokinetic profile that permits once-daily intravenous administration. Doses of 7.5 and 10 mg/kg/day have been studied in clinical trials. The need for dosage adjustments based on age, gender and obesity appear unnecessary. In addition, moderate hepatic impairment does not appreciably alter the pharmacokinetics of the drug. Because telavancin is extensively cleared by the kidneys, dosage adjustments will be required in patients with moderate to severe renal impairment. Published phase II and III clinical trials have shown telavancin to be comparable to standard therapy for the treatment of complicated skin and soft tissue infections. Clinical trials in the treatment of S. aureus bacteremia and hospital-acquired pneumonia are under way. Adverse effects overall appear to be mild and reversible, with taste disturbance, foamy urine, headache, procedural site pain, nausea and vomiting being the most commonly reported. However, renal toxicity was reported more frequently with telavancin than with vancomycin in two phase III clinical trials (3% versus 1%). Prolongation of the corrected QT (QTc) interval has been more common with telavancin than comparator agents, but no clinically significant electrocardiogram (ECG) changes or cardiac abnormalities have been observed to date. Although human pregnancy data is not currently available, animal data revealed limb malformations that were possibly related to telavancin therapy. Therefore, the potential teratogenicity of this agent must be considered in women who are pregnant or may become pregnant. PMID:19436839

Smith, Winter J; Drew, Richard H

2009-03-01

181

Antibacterial and antifungal activities of acetonic extract from Paullinia cupana Mart. seeds.  

PubMed

The antibacterial and antifungal activities of the acetone extract from Paullinia cupana var. sorbilis Mart. (Sapindaceae) seeds, commonly called guarana, were assessed against selected bacterial and fungal strains. We tested the extract against both standard American Type Culture Collection (ATCC) and clinically isolated (CI) bacterial strains and three fungal strains. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for bacteria and MIC and minimum fungicidal concentration for fungi were determined. The extract showed an activity against the nine bacterial strains tested, both CI and ATCC strains (MIC comprised between 32 and 128 ?m/mL and MBC between 128 and 512 ?m/mL), showing a significant antibacterial effect against both Gram-negative and Gram-positive bacteria. Also, the tested fungi were sensitive to the extract (MIC between 125 and 250 ?m/mL). The contemporaneous presence of different bioactivities in the extract from guarana suggests this plant as a source of bioactive substances. PMID:23672664

Basile, Adriana; Rigano, Daniela; Conte, Barbara; Bruno, Maurizio; Rosselli, Sergio; Sorbo, Sergio

2013-01-01

182

Antibacterial properties of propolis (bee glue).  

PubMed Central

Propolis (bee glue) was found to have antibacterial activity against a range of commonly encountered cocci and Gram-positive rods, including the human tubercle bacillus, but only limited activity against Gram-negative bacilli. These findings confirm previous reports of antimicrobial properties of this material, possibly attributable to its high flavonoid content.

Grange, J M; Davey, R W

1990-01-01

183

Antibacterial Acativity of Thymoquinone and Thymohydroquinone of Nigella sativa L. and Their Interaction with Some Antibiotics  

Microsoft Academic Search

The two main components of black seed essential oil, thymoquinone (TQ) and thymohydroquinone (THQ) were investigated for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Shigella flexneri, Salmonella Typhimurium, Salmonella Enteritidis and Staphylococcus aureus. Both TQ and THQ exerted antibacterial activity against gram-positive and gram-negative bacteria regardless to thei r susceptibility to antibiotics. S. aureus, was highly susceptible to TQ,

Eman Halawani

184

Coriander (Coriandrum sativum L.) essential oil: its antibacterial activity and mode of action evaluated by flow cytometry.  

PubMed

The aim of this work was to study the antibacterial effect of coriander (Coriandrum sativum) essential oil against Gram-positive and Gram-negative bacteria. Antibacterial susceptibility was evaluated using classical microbiological techniques concomitantly with the use of flow cytometry for the evaluation of cellular physiology. Our results showed that coriander oil has an effective antimicrobial activity against all bacteria tested. Also, coriander oil exhibited bactericidal activity against almost all bacteria tested, with the exception of Bacillus cereus and Enterococcus faecalis. Propidium iodide incorporation and concomitant loss of all other cellular functions such as efflux activity, respiratory activity and membrane potential seem to suggest that the primary mechanism of action of coriander oil is membrane damage, which leads to cell death. The results obtained herein further encourage the use of coriander oil in antibacterial formulations due to the fact that coriander oil effectively kills pathogenic bacteria related to foodborne diseases and hospital infections. PMID:21862758

Silva, Filomena; Ferreira, Susana; Queiroz, João A; Domingues, Fernanda C

2011-10-01

185

Silver/poly (lactic acid) nanocomposites: preparation, characterization, and antibacterial activity  

PubMed Central

In this study, antibacterial characteristic of silver/poly (lactic acid) nanocomposite (Ag/PLA-NC) films was investigated, while silver nanoparticles (Ag-NPs) were synthesized into biodegradable PLA via chemical reduction method in diphase solvent. Silver nitrate and sodium borohydride were respectively used as a silver precursor and reducing agent in the PLA, which acted as a polymeric matrix and stabilizer. Meanwhile, the properties of Ag/PLA-NCs were studied as a function of the Ag-NP weight percentages (8, 16, and 32 wt% respectively), in relation to the use of PLA. The morphology of the Ag/PLA-NC films and the distribution of the Ag-NPs were also characterized. The silver ions released from the Ag/PLA-NC films and their antibacterial activities were scrutinized. The antibacterial activities of the Ag/PLA-NC films were examined against Gram-negative bacteria (Escherichia coli and Vibrio parahaemolyticus) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using Muller–Hinton agar. The results indicated that Ag/PLA-NC films possessed a strong antibacterial activity with the increase in the percentage of Ag-NPs in the PLA. Thus, Ag/PLA-NC films can be used as an antibacterial scaffold for tissue engineering and medical application.

Shameli, Kamyar; Ahmad, Mansor Bin; Yunus, Wan Md Zin Wan; Ibrahim, Nor Azowa; Rahman, Russly Abdul; Jokar, Maryam; Darroudi, Majid

2010-01-01

186

Bacitracin-conjugated superparamagnetic iron oxide nanoparticles: synthesis, characterization and antibacterial activity.  

PubMed

Bacitracin-conjugated superparamagnetic iron oxide (Fe(3)O(4)) nanoparticles were prepared by click chemistry and their antibacterial activity was investigated. After functionalization with hydrophilic and biocompatible poly(acrylic acid), water-soluble Fe(3)O(4) nanoparticles were obtained. Propargylated Fe(3)O(4) nanoparticles were then synthesized by carbodiimide reaction of propargylamine with the carboxyl groups on the surface of the iron oxide nanoparticles. By further reaction with N(3)-bacitracin in a Cu(I)-catalyzed azide-alkyne cycloaddition, the magnetic Fe(3)O(4) nanoparticles were modified with the peptide bacitracin. The functionalized magnetic nanoparticles were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, TEM, zeta-potential analysis, FTIR spectroscopy and vibrating-sample magnetometry. Cell cytotoxicity tests indicate that bacitracin-conjugated Fe(3)O(4) nanoparticles show very low cytotoxicity to human fibroblast cells, even at relatively high concentrations. In view of the antibacterial activity of bacitracin, the biofunctionalized Fe(3)O(4) nanoparticles exhibit an antibacterial effect against both Gram-positive and Gram-negative organisms, which is even higher than that of bacitracin itself. The enhanced antibacterial activity of the magnetic nanocomposites allows the dosage and the side effects of the antibiotic to be reduced. Due to the antibacterial effect and magnetism, the bacitracin-functionalized magnetic nanoparticles have potential application in magnetic-targeting biomedical applications. PMID:22753190

Zhang, Wenjing; Shi, Xinhao; Huang, Jing; Zhang, Yixuan; Wu, Zirong; Xian, Yuezhong

2012-10-01

187

Biological activity of five antibacterial flavonoids from Combretum erythrophyllum (Combretaceae).  

PubMed

Preliminary studies with Combretum erythrophyllum showed antimicrobial activity against Gram-positive and Gram-negative bacteria. Seven antibacterial flavonoids were subsequently isolated by bioassay-guided fractionation, i.e. apigenin; genkwanin; 5-hydroxy-7,4'-dimethoxyflavone, rhamnocitrin; kaempferol; quercetin-5,3'-dimethylether; rhamnazin. All compounds had good activity against Vibrio cholerae and Enterococcus faecalis, with MIC values in the range of 25-50 microg/ml. Rhamnocitrin and quercetin-5,3'-dimethylether also inhibited Micrococcus luteus and Shigella sonei at 25 microg/ml. With the exception of 5-hydroxy-7,4'-dimethoxy-flavone the flavonoids were not toxic towards human lymphocytes. This compound is potentially toxic to human cells and exhibited the poorest antioxidant activity whereas rhamnocitrin and rhamnazin exhibited strong antioxidant activity. Genkwanin; rhamnocitrin; quercetin-5,3'-dimethylether; rhamnazin had a higher anti-inflammatory activity than the positive control mefenamic acid. Although these flavonoids are known, this is the first report of biological activity with several of these compounds. PMID:15234754

Martini, N D; Katerere, D R P; Eloff, J N

2004-08-01

188

Optical control of antibacterial activity  

NASA Astrophysics Data System (ADS)

Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

2013-11-01

189

The acetylproteome of Gram-positive model bacterium Bacillus subtilis.  

PubMed

N(?) -lysine acetylation, a reversible and highly regulated PTM, has been shown to occur in the model Gram-negative bacteria Escherichia coli and Salmonella enterica. Here, we extend this acetylproteome analysis to Bacillus subtilis, a model Gram-positive bacterium. Through anti-acetyllysine antibody-based immunoseparation of acetylpeptides followed by nano-HPLC/MS/MS analysis, we identified 332 unique lysine-acetylated sites on 185 proteins. These proteins are mainly involved in cellular housekeeping functions such as central metabolism and protein synthesis. Fifity-nine of the lysine-acetylated proteins showed homology with lysine-acetylated proteins previously identified in E. coli, suggesting that acetylated proteins are more conserved. Notably, acetylation was found at or near the active sites predicted by Prosite signature, including SdhA, RocA, Kbl, YwjH, and YfmT, indicating that lysine acetylation may affect their activities. In 2-amino-3-ketobutyrate CoA ligase Kbl, a class II aminotransferase, a lysine residue involved in pyridoxal phosphate attachment was found to be acetylated. This data set provides evidence for the generality of lysine acetylation in eubacteria and opens opportunities to explore the consequences of acetylation modification on the molecular physiology of B. subtilis. PMID:23468065

Kim, Dooil; Yu, Byung Jo; Kim, Jung Ae; Lee, Yong-Jik; Choi, Soo-Geun; Kang, Sunghyun; Pan, Jae-Gu

2013-05-01

190

Regulation of Apoptosis by Gram-Positive Bacteria  

PubMed Central

Apoptosis, or programmed cell death (PCD), is an important physiological mechanism, through which the human immune system regulates homeostasis and responds to diverse forms of cellular damage. PCD may also be involved in immune counteraction to microbial infection. Over the past decade, the amount of research on bacteria-induced PCD has grown tremendously, and the implications of this mechanism on immunity are being elucidated. Some pathogenic bacteria actively trigger the suicide response in critical lineages of leukocytes that orchestrate both the innate and adaptive immune responses; other bacteria proactively prevent PCD to benefit their own survival and persistence. Currently, the microbial virulence factors, which represent the keys to unlocking the suicide response in host cells, are a primary focus of this field. In this review, we discuss these bacterial “apoptosis regulatory molecules” and the apoptotic events they either trigger or prevent, the host target cells of this regulatory activity, and the possible ramifications for immunity to infection. Gram-positive pathogens including Staphylococcus, Streptococcus, Bacillus, Listeria, and Clostridia species are discussed as important agents of human infection that modulate PCD pathways in eukaryotic cells.

Ulett, Glen C.; Adderson, Elisabeth E.

2008-01-01

191

Interaction of Cationic Peptides with Lipoteichoic Acid and Gram-Positive Bacteria  

PubMed Central

Compounds with antiendotoxin properties have been extensively studied for their potential as therapeutic agents for sepsis attributable to gram-negative bacteria. However, with the increasing incidence of gram-positive sepsis, there is interest in identifying compounds with a broad spectrum of action against both gram-positive and gram-negative bacteria. A series of synthetic ?-helical cationic peptides related to bee melittin and silk moth cecropin have previously been shown to bind lipopolysaccharide (LPS) with high affinity, inhibit LPS-induced tumor necrosis factor alpha (TNF-?) production in vitro and in vivo, and kill gram-negative bacteria. In this study, we analyzed whether these peptides were active against gram-positive bacteria; whether they could bind to lipoteichoic acid (LTA), the major proinflammatory structure on gram-positive bacteria; and whether they could block the ability of LTA to promote the release of cytokines by the RAW 264.7 murine macrophage cell line. We found that the cationic peptides demonstrated moderate growth-inhibitory activity toward gram-positive bacteria. In addition, the peptides bound LTA with high affinity. This correlated with the ability of the peptides to block LTA-induced production of TNF and interleukin-6 by RAW 264.7 cells but did not correlate with their ability to kill the bacteria. The peptides also effectively inhibited LTA-induced TNF production in a whole human blood assay. The peptides were also able to partly block the ability of heat-killed Staphylococcus aureus, as well as soluble products of live S. aureus, to stimulate cytokine production by macrophages. Our results indicate that these cationic peptides may be useful to prevent sepsis and inflammation caused by both gram-negative and gram-positive bacteria.

Scott, Monisha G.; Gold, Michael R.; Hancock, Robert E. W.

1999-01-01

192

Investigation of structural, dielectric, magnetic and antibacterial activity of Cu-Cd-Ni-FeO4 nanoparticles  

NASA Astrophysics Data System (ADS)

Nanoparticles of Cu-Cd-Ni-FeO4 were synthesized by the auto-combustion process using a modified citric acid method. Antibacterial activity, structural, dielectric and magnetic properties were investigated. An assay showed the broad spectrum antibacterial activity of Cu-Cd-Ni-FeO4 against Gram positive and Gram negative pathogenic bacterial strains. The existence of single phase cubic spinel structure of ferrites was confirmed by X-ray diffraction measurement. Fourier transform infrared spectroscopy shows the two main absorption bands at lower frequency region. Surface morphology and compositional features were studied by scanning electron microscopy and energy dispersive X-ray spectroscopy analysis, respectively. Results indicated that the nanosize particles greatly influenced the antibacterial activity, as well as structural, dielectric and magnetic properties of the samples. Magnetic measurements of the samples were carried out by means of vibrating sample magnetometry and Mössbauer spectroscopy. Magnetic properties are strongly affected by Ni2+ substitution.

Hashim, Mohd.; Alimuddin; Shirsath, Sagar E.; Meena, S. S.; Kotnala, R. K.; Parveen, Ameena; Roy, Aashis S.; Kumar, Shalendra; Bhatt, Pramod; Kumar, Ravi

2013-09-01

193

Characterization and bioactivity of hepcidin-2 in zebrafish: Dependence of antibacterial activity upon disulfide bridges.  

PubMed

Hepcidin is an antimicrobial peptide and iron-regulatory molecule with highly conserved disulfide bridges among vertebrates, but structural insights into the function in fish remains largely missing. We demonstrate here that recombinant hepcidin-2 from zebrafish is capable of inhibiting the growth of the Gram-negative bacteria Escherichia coli and Vibrio anguillarum, and the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with minimum inhibitory concentrations (MICs) of 18, 15, 13 and 9?M, respectively. We also show by TEM examination that recombinant hepcidin-2 is directly cidal to the cells of E. coli and S. aureus. Moreover, we find that hepcidin-2 displays affinity to LPS, LTA and PGN. All these data indicate that hepcidin-2 is both a pattern recognition molecule, capable of identifying LPS, LTA and PGN, and an antibacterial effector, capable of inhibiting the growth of bacteria. The data also show that the antibacterial activity of hepcidin-2 depends upon the disulfide bridges. PMID:24787654

Lin, Wenjing; Liu, Shousheng; Hu, Lili; Zhang, Shicui

2014-07-01

194

Antibacterial activity of some lichen extracts  

Microsoft Academic Search

The aqueous and ethanol extracts prepared from some lichens species were evaluated for antibacterial activity against six standard strains (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Klebsiella pneumoniae, Staphylococcus aureus and Staphylococcus epidermidis) and two environmental strains (Aeromonas) that were isolated from different lakes. The aqueous and ethanol extracts showed a variable range of antibacterial activity to both standard strains and

Ali Karagöz; Nihal Doruöz; Zuhal Zeybek; Ali Aslan

2009-01-01

195

Assessment of Tamarindus indica Extracts for Antibacterial Activity  

PubMed Central

Ethanolic and aqueous (hot and cold) extracts of the fruit pulp, stem bark and leaves of Tamarindus indica were evaluated for antibacterial activity, in vitro, against 13 Gram negative and 5 Gram positive bacterial strains using agar well diffusion and macro broth dilution techniques, simultaneously. The fruit pulp extracts exhibited a wide spectrum of activity; the cold water extract against 95.5% of the test bacterial strains; and the hot water and ethanolic extracts against 90.9% and 86.4%, respectively. In contrast the cold water extract of the leaves and stem bark, each was active against 16.7%; while the ethanolic extract of each was active against 75% of the test strains. The minimum inhibitory concentrations (MIC) ranged from 7.81 mg/mL against Bacillus subtilis ATCC 6051 to 31.25 mg/mL against Escherichia coli ATCC 11775; and the minimum bactericidal concentration (MBC) ranged from 125 mg/mL against Pseudomonas aeruginosa ATCC 10145 to 250 mg/mL against Bacillus subtilis ATCC 6051.

Nwodo, Uchechukwu U.; Obiiyeke, Grace E.; Chigor, Vincent N.; Okoh, Anthony I.

2011-01-01

196

Evaluation of the antibacterial activity of Ventilago madraspatana Gaertn., Rubia cordifolia Linn. and Lantana camara Linn.: isolation of emodin and physcion as active antibacterial agents.  

PubMed

The antibacterial activity of the extracts of Ventilago madraspatana stem-bark, Rubia cordifolia root and Lantana camara root-bark, prepared with solvents of different polarity, was evaluated by the agar-well diffusion method. Twelve bacteria, six each of gram-positive and gram-negative strains, were used in this study. Chloroform and ethanol extracts of V. madraspatana showed broad-spectrum activity against most of the bacteria except S. aureus, E. coli and V. cholerae. On the other hand, the activity of the chloroform and methanol extracts of R. cordifolia and L. camara was found to be more specific towards the gram-positive strains, although gram-negative P. aeruginosa was also inhibited by the methanol extracts of both these plants in a dose dependent manner. The water extracts of V. madraspatana and L. camara were found to be inactive, while that of R. cordifolia was significantly active against B. subtilis and S. aureus compared with streptomycin and penicillin G used as standards. In the course of bio-assay guided fractionation, emodin and physcion were isolated for the first time from the stem-bark of V. madraspatana. It was noteworthy to find the MICs of emodin in the range 0.5-2.0 microg/mL against three Bacillus sp. Both the anthraquinonoid compounds inhibited P. aeruginosa, emodin being more effective, showing an MIC of 70 microg/mL. PMID:16261521

Basu, Subhalakshmi; Ghosh, Abhijit; Hazra, Banasri

2005-10-01

197

Antibacterial activities of Sesbania grandiflora extracts.  

PubMed

In this study, Sesbania grandiflora, a plant in the Leguminosae family, was investigated for its antibacterial activities. The agar well diffusion assay as well as the agar and broth dilution assays were used for determination of antibacterial activities. The crude ethanolic extracts obtained from different parts of this plant exhibited different potent activities. The stem bark has the most potential to yield an extract with the highest antibacterial action. The fractionation of the stem bark with different solvents indicated that the fractionated extracts obtained from ethyl acetate or butanol possessed the most pronounced antibacterial activity. The kinetic study of bactericidal activities revealed that the butanol fractionated extract of the stem bark was effective against Gram negative bacteria. This study suggests that the stem bark of S. grandiflora contains promising antibacterial substances for clinical purposes. PMID:22466091

Anantaworasakul, P; Klayraung, S; Okonogi, S

2011-02-01

198

Synthesis, antibacterial activity, and quantitative structure-activity relationships of new (Z)-2-(nitroimidazolylmethylene)-3(2H)-benzofuranone derivatives.  

PubMed

A new series of (Z)-2-(1-methyl-5-nitroimidazole-2-ylmethylene)-3(2H)-benzofuranones (11a-p) and (Z)-2-(1-methyl-4-nitroimidazole-5-ylmethylene)-3(2H)-benzofuranones (12a-m) were synthesized and assayed for their antibacterial activity against Gram-positive and Gram-negative bacteria. Most of the 5-nitroimidazole analogues (11a-p) showed a remarkable inhibition of a wide spectrum of Gram-positive bacteria (Staphylococcus aureus, Streptococcus epidermidis, MRSA, and Bacillus subtilis) and Gram-negative Klebsiella pneumoniae, whereas 4-nitroimidazole analogues (12a-m) were not effective against selected bacteria. The quantitative structure-activity relationship investigations were applied to find out the correlation between the experimentally evaluated activities with various parameters of the compounds studied. The QSAR models built in this work had reasonable predictive power and could be explained by the observed trends in activities. PMID:17919903

Hadj-esfandiari, Narges; Navidpour, Latifeh; Shadnia, Hooman; Amini, Mohsen; Samadi, Nasrin; Faramarzi, Mohammad Ali; Shafiee, Abbas

2007-11-15

199

Preparation and antibacterial activity of Fe3O4@Ag nanoparticles  

NASA Astrophysics Data System (ADS)

Bifunctional Fe3O4@Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 ± 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe3O4 and silver are present in the same particle. The superparamagnetism of Fe3O4@Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe3O4@Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe3O4@Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe3O4@Ag nanoparticles can still have antibacterial capability and can be reused.

Gong, Ping; Li, Huimin; He, Xiaoxiao; Wang, Kemin; Hu, Jianbing; Tan, Weihong; Zhang, Shouchun; Yang, Xiaohai

2007-07-01

200

Antibacterial activity of thioetherhydroxyethylsulfonamide derivatives.  

PubMed

Thioetherhydroxyethylsulfonamide derivatives were synthesized and evaluated for their in vitro antibacterial activity against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923). Results have shown that compounds 8c and 9e display potent activity (MIC = 0.125 µg/mL) against E. coli when compared with the standard drug sulfamethoxazole (SMZ, MIC < 0.5 µg/mL) for this same strain. All the new compounds were fully identified and characterized by NMR ((1)H and (13)C) and X-ray crystallography (for compound 8c). This class of compounds can be considered as a good starting point for the development of new lead molecules in the fight against multi-drug bacterial resistance. PMID:24533504

Vellasco, Walcimar T; Guedes, Guilherme P; Facchinetti, Victor; Vasconcelos, Thatyana R A; Vaz, Maria G F; Cunico, Wilson; de Souza, Marcus V N; de Paula, Geraldo R; Fleming, Maria E C K; Gomes, Claudia R B

2014-05-01

201

Antimicrobial glycopeptides: synthesis and antibacterial activity of N-linked and O-linked smaller chain glycopeptides.  

PubMed

Our objective is to synthesize the smaller chain N-linked and O-linked glycopeptides using sugars belong to mono, di and polysaccharides, with the efforts mainly directed towards the identification of antibacterial compounds. 7 glycopeptides, viz., Arg-Asn-Mannose, Arg-Asn-Lactose, His-Asn-Mannose, His-Asn-Lactose (N-glycopeptides), Arg-Ser-Lactose, Arg-Thr-Lactose, Arg-Thr-Starch (O-glycopeptides) were prepared by dicyclohexyl carbodimide (DCC) coupling for amino acids using microwave oven (50W power; 15?min) and activated and coupled with respective sugar moieties using microwave oven at 120?W for 20-25?min. The column eluted compounds were tested for disc diffusion assay using 3 gram positive S. aureus, B. subtilis, S. caprae and 3 gram negative E. coli, P. aeruginosa and S. sonnei strains at different concentrations predicted by pH and inhibitory concentrations. One of the test glycopeptide, His-Asn-Lactose was found to be very effective against all the microbial strains tested and 3 other Test Compounds, viz., His-Asn-Mannose, Arg-Thr-Lactose and Arg-Thr-Starch are also proved to be effective against 2?gram positive and 2?gram negative strains tested. Maximum activity was observed at a concentration of 450??g/ml (747.51?µM) for the N-glycopeptide His-Asn-Lactose with the corresponding zonal inhibition diameters (15?mm; 19?mm; 14?mm; 18?mm; 16?mm; 17?mm) against S. aureus, B. subtilis, S. caprae, E. coli, P. aeruginosa, S. sonnei. This is the first evidence based report that our N-glycopeptide, His-Asn-Lactose tested, has shown antibacterial action against both gram positive and gram negative strains. Further in vivo testing and clinical studies will make sure to position our potent small chain N-glycopeptide in the arsenal of new broad spectrum anti-gram positive and negative agent. PMID:24026960

Nagarajan, K; Taleuzzamman, M; Kumar, V; Singh, S; Singh, J; Panda, B P; Ghosh, L K

2014-04-01

202

EVALUATION OF ANTIBACTERIAL ACTIVITY OF BERGENIA CILIATA  

Microsoft Academic Search

Bergenia ciliata was subjected to antibacterial analysis. A battery of assays were performed on different extracts of Bergenia ciliata for antibacterialactivities. Antibacterial effects of ethanol, hexane, ethyl acetate, chloroform, butanol and aqueous extracts of the roots and leaves extract of Bergenia ciliata exhibited various degree of inhibition activity. It was observed that root and leaves extract were promising against gram

IQBAL AZHAR; FARAH MAZHAR; KHAN USMANGHANI; MUHAMMAD ASLAM GILL; AFZAL AHMAD

203

Novel antimicrobial peptides that inhibit gram positive bacterial exotoxin synthesis.  

PubMed

Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and ?-globin and ?-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized ?-globin chain peptides, synthetic variants of ?-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges. PMID:24748386

Merriman, Joseph A; Nemeth, Kimberly A; Schlievert, Patrick M

2014-01-01

204

Protein secretion and surface display in Gram-positive bacteria  

PubMed Central

The cell wall peptidoglycan of Gram-positive bacteria functions as a surface organelle for the transport and assembly of proteins that interact with the environment, in particular, the tissues of an infected host. Signal peptide-bearing precursor proteins are secreted across the plasma membrane of Gram-positive bacteria. Some precursors carry C-terminal sorting signals with unique sequence motifs that are cleaved by sortase enzymes and linked to the cell wall peptidoglycan of vegetative forms or spores. The sorting signals of pilin precursors are cleaved by pilus-specific sortases, which generate covalent bonds between proteins leading to the assembly of fimbrial structures. Other precursors harbour surface (S)-layer homology domains (SLH), which fold into a three-pronged spindle structure and bind secondary cell wall polysaccharides, thereby associating with the surface of specific Gram-positive microbes. Type VII secretion is a non-canonical secretion pathway for WXG100 family proteins in mycobacteria. Gram-positive bacteria also secrete WXG100 proteins and carry unique genes that either contribute to discrete steps in secretion or represent distinctive substrates for protein transport reactions.

Schneewind, Olaf; Missiakas, Dominique M.

2012-01-01

205

Antibacterial Activity of Polyphenols of Garcinia Indica  

PubMed Central

The aim of present work is to study the antibacterial activity of polyphenols isolated from the ethyl acetate soluble of methanol extract of stem bark of Garcinia indica against Staphylococcus aureus, Salmonella typhi and Escherichia coli by paper disc method. The results showed good antibacterial activity against S. aureus at higher concentrations, moderate at lower concentrations, against S. typhi moderate at higher concentrations but no activity against E. coli even at higher concentration for flavononylflavone. With proauthocyanin S. Aureus, S. Typhi and E. coli showed good antibacterial activity at higher concentration only.

Lakshmi, C.; Kumar, K. Akshaya; Dennis, T. J.; Kumar, T. S. S. P. N. S. Sanath

2011-01-01

206

Conjugative Plasmid Transfer in Gram-Positive Bacteria  

PubMed Central

Conjugative transfer of bacterial plasmids is the most efficient way of horizontal gene spread, and it is therefore considered one of the major reasons for the increase in the number of bacteria exhibiting multiple-antibiotic resistance. Thus, conjugation and spread of antibiotic resistance represents a severe problem in antibiotic treatment, especially of immunosuppressed patients and in intensive care units. While conjugation in gram-negative bacteria has been studied in great detail over the last decades, the transfer mechanisms of antibiotic resistance plasmids in gram-positive bacteria remained obscure. In the last few years, the entire nucleotide sequences of several large conjugative plasmids from gram-positive bacteria have been determined. Sequence analyses and data bank comparisons of their putative transfer (tra) regions have revealed significant similarities to tra regions of plasmids from gram-negative bacteria with regard to the respective DNA relaxases and their targets, the origins of transfer (oriT), and putative nucleoside triphosphatases NTP-ases with homologies to type IV secretion systems. In contrast, a single gene encoding a septal DNA translocator protein is involved in plasmid transfer between micelle-forming streptomycetes. Based on these clues, we propose the existence of two fundamentally different plasmid-mediated conjugative mechanisms in gram-positive microorganisms, namely, the mechanism taking place in unicellular gram-positive bacteria, which is functionally similar to that in gram-negative bacteria, and a second type that occurs in multicellular gram-positive bacteria, which seems to be characterized by double-stranded DNA transfer.

Grohmann, Elisabeth; Muth, Gunther; Espinosa, Manuel

2003-01-01

207

Moderately halophilic gram-positive bacterial diversity in hypersaline environments.  

PubMed

Moderately halophilic bacteria are microorganisms that grow optimally in media containing 3%-15% (w/v) salt. They are represented by a heterogeneous group of microorganisms included in many different genera. Gram-negative moderately halophilic bacteria have been studied in more detail, but studies on gram-positive species are more scarce. Recent studies carried out by our research group on gram-positive moderate halophiles have permitted clarifying their taxonomic and phylogenetic position and describing new species. Thus, we have isolated six strains from ponds of salterns that show phenotypic and genotypic characteristics similar to those of Nesterenkonia halobia (formerly Micrococcus halobius), a moderately halophilic gram-positive coccus that was described on the basis of a single strain. Our data demonstrate quite clearly that they are members of this species and contribute to a better description of these moderately halophilic cocci. Similarly, a study of a large number of gram-positive moderately halophilic rods that were able to produce endospores led us to describe a new species, designated Bacillus salexigens. Further, isolates grouped in other three phenons, obtained by numerical taxonomy analysis and showing phenotypic features quite similar to those of this species, represent different genomovars, with very low DNA-DNA homology. Although they might represent additional new species, it will be necessary to determine new phenotypic features to differentiate them from previously described Bacillus species. We have also studied the viability of some old enrichments provided by B.E. Volcani, which were set up in 1936. We isolated 31 gram-positive motile endospore-forming rods that, according to their phenotypic characteristics, could represent a new species of the genus Bacillus. PMID:9783177

Ventosa, A; Márquez, M C; Garabito, M J; Arahal, D R

1998-08-01

208

Glucosamine-functionalized silver glyconanoparticles: characterization and antibacterial activity.  

PubMed

We report the analytical and in vitro antibacterial activity of glucosamine-functionalized silver glyconanoparticles. Morphological characterization ensured the surface topography and particle size distribution of both silver and glucosamine-silver nanoparticles. Surface plasmon resonance of both types of nanoparticle was determined from UV-visible spectroscopy using four different sample concentrations (10-40 ?L). The resulting functionalized glyconanoparticles show maximum absorbance with a red shift of 30?±?5 nm (390-400 nm) from their initial absorbance (425-430 nm). FT-Raman and (1)H-NMR spectroscopic measurement confirmed the surface functionalization of glucosamine on the silver surface through the carbonyl group of a secondary amide linkage (-NH-CO-), elucidated by the conjugation of N-hydroxysuccinimide (NHS)-terminated silver nanoparticles and the amino group of glucosamine. Antimicrobial experiments with well-characterized silver nanoparticles (AgNPs) and glucosamine-functionalized silver nanoparticles (GlcN-AgNPs) demonstrate that GlcN-AgNPs have similar and enhanced minimum inhibitory concentration (MIC) against eight gram-negative and eight gram-positive bacteria compared with AgNPs. MIC data shows that Klebsiella pneumoniae (ATCC 700603) and Bacillus cereus isolate express high levels of inhibition, with the quantity and magnitude of inhibition being higher in the presence of GlcN-AgNPs. PMID:20623220

Veerapandian, Murugan; Lim, Suk Kyung; Nam, Hyang Mi; Kuppannan, Gobianand; Yun, Kyusik S

2010-09-01

209

Distinct localization of the complement C5b-9 complex on Gram-positive bacteria.  

PubMed

The plasma proteins of the complement system fulfil important immune defence functions, including opsonization of bacteria for phagocytosis, generation of chemo-attractants and direct bacterial killing via the Membrane Attack Complex (MAC or C5b-9). The MAC is comprised of C5b, C6, C7, C8, and multiple copies of C9 that generate lytic pores in cellular membranes. Gram-positive bacteria are protected from MAC-dependent lysis by their thick peptidoglycan layer. Paradoxically, several Gram-positive pathogens secrete small proteins that inhibit C5b-9 formation. In this study, we found that complement activation on Gram-positive bacteria in serum results in specific surface deposition of C5b-9 complexes. Immunoblotting revealed that C9 occurs in both monomeric and polymeric (SDS-stable) forms, indicating the presence of ring-structured C5b-9. Surprisingly, confocal microscopy demonstrated that C5b-9 deposition occurs at specialized regions on the bacterial cell. On Streptococcus pyogenes, C5b-9 deposits near the division septum whereas on Bacillus subtilis the complex is located at the poles. This is in contrast to C3b deposition, which occurs randomly on the bacterial surface. Altogether, these results show a previously unrecognized interaction between the C5b-9 complex and Gram-positive bacteria, which might ultimately lead to a new model of MAC assembly and functioning. PMID:23869880

Berends, Evelien T M; Dekkers, Johanna F; Nijland, Reindert; Kuipers, Annemarie; Soppe, Jasper A; van Strijp, Jos A G; Rooijakkers, Suzan H M

2013-12-01

210

Antibacterial and antifungal activities from leaf extracts of Cassia fistula l.: An ethnomedicinal plant.  

PubMed

This study was carried out with an objective to investigate the antibacterial and antifungal potentials of leaves of Cassia fistula Linn. The aim of the study is to assess the antimicrobial activity and to determine the zone of inhibition of extracts on some bacterial and fungal strains. In the present study, the microbial activity of hydroalcohol extracts of leaves of Cassia fistula Linn. (an ethnomedicinal plant) was evaluated for potential antimicrobial activity against medically important bacterial and fungal strains. The antimicrobial activity was determined in the extracts using agar disc diffusion method. The antibacterial and antifungal activities of extracts (5, 25, 50, 100, 250 ?g/ml) of Cassia fistula were tested against two Gram-positive-Staphylococcus aureus, Streptococcus pyogenes; two Gram-negative-Escherichia coli, Pseudomonas aeruginosa human pathogenic bacteria; and three fungal strains-Aspergillus niger, Aspergillus clavatus, Candida albicans. Zone of inhibition of extracts were compared with that of different standards like ampicillin, ciprofloxacin, norfloxacin, and chloramphenicol for antibacterial activity and nystatin and griseofulvin for antifungal activity. The results showed that the remarkable inhibition of the bacterial growth was shown against the tested organisms. The phytochemical analyses of the plants were carried out. The microbial activity of the Cassia fistula was due to the presence of various secondary metabolites. Hence, these plants can be used to discover bioactive natural products that may serve as leads in the development of new pharmaceuticals research activities. PMID:22171301

Bhalodia, Nayan R; Shukla, V J

2011-04-01

211

Antibacterial and antifungal activities from leaf extracts of Cassia fistula l.: An ethnomedicinal plant  

PubMed Central

This study was carried out with an objective to investigate the antibacterial and antifungal potentials of leaves of Cassia fistula Linn. The aim of the study is to assess the antimicrobial activity and to determine the zone of inhibition of extracts on some bacterial and fungal strains. In the present study, the microbial activity of hydroalcohol extracts of leaves of Cassia fistula Linn. (an ethnomedicinal plant) was evaluated for potential antimicrobial activity against medically important bacterial and fungal strains. The antimicrobial activity was determined in the extracts using agar disc diffusion method. The antibacterial and antifungal activities of extracts (5, 25, 50, 100, 250 ?g/ml) of Cassia fistula were tested against two Gram-positive—Staphylococcus aureus, Streptococcus pyogenes; two Gram-negative—Escherichia coli, Pseudomonas aeruginosa human pathogenic bacteria; and three fungal strains—Aspergillus niger, Aspergillus clavatus, Candida albicans. Zone of inhibition of extracts were compared with that of different standards like ampicillin, ciprofloxacin, norfloxacin, and chloramphenicol for antibacterial activity and nystatin and griseofulvin for antifungal activity. The results showed that the remarkable inhibition of the bacterial growth was shown against the tested organisms. The phytochemical analyses of the plants were carried out. The microbial activity of the Cassia fistula was due to the presence of various secondary metabolites. Hence, these plants can be used to discover bioactive natural products that may serve as leads in the development of new pharmaceuticals research activities.

Bhalodia, Nayan R.; Shukla, V. J.

2011-01-01

212

Particle-Cell Contact Enhances Antibacterial Activity of Silver Nanoparticles  

PubMed Central

Background It is generally accepted that antibacterial properties of Ag nanoparticles (AgNPs) are dictated by their dissolved fraction. However, dissolution-based concept alone does not fully explain the toxic potency of nanoparticulate silver compared to silver ions. Methodology/Principal Findings Herein, we demonstrated that the direct contact between bacterial cell and AgNPs' surface enhanced the toxicity of nanosilver. More specifically, cell-NP contact increased the cellular uptake of particle-associated Ag ions – the single and ultimate cause of toxicity. To prove that, we evaluated the toxicity of three different AgNPs (uncoated, PVP-coated and protein-coated) to six bacterial strains: Gram-negative Escherichia coli, Pseudomonas fluorescens, P. putida and P. aeruginosa and Gram-positive Bacillus subtilis and Staphylococcus aureus. While the toxicity of AgNO3 to these bacteria varied only slightly (the 4-h EC50 ranged from 0.3 to 1.2 mg Ag/l), the 4-h EC50 values of protein-coated AgNPs for various bacterial strains differed remarkably, from 0.35 to 46 mg Ag/l. By systematically comparing the intracellular and extracellular free Ag+ liberated from AgNPs, we demonstrated that not only extracellular dissolution in the bacterial test environment but also additional dissolution taking place at the particle-cell interface played an essential role in antibacterial action of AgNPs. The role of the NP-cell contact in dictating the antibacterial activity of Ag-NPs was additionally proven by the following observations: (i) separation of bacterial cells from AgNPs by particle-impermeable membrane (cut-off 20 kDa, ?4 nm) significantly reduced the toxicity of AgNPs and (ii) P. aeruginosa cells which tended to attach onto AgNPs, exhibited the highest sensitivity to all forms of nanoparticulate Ag. Conclusions/Significance Our findings provide new insights into the mode of antibacterial action of nanosilver and explain some discrepancies in this field, showing that “Ag-ion” and “particle-specific” mechanisms are not controversial but, rather, are two faces of the same coin.

Bondarenko, Olesja; Ivask, Angela; Kakinen, Aleksandr; Kurvet, Imbi; Kahru, Anne

2013-01-01

213

Antibacterial and leishmanicidal activities of temporin-SHd, a 17-residue long membrane-damaging peptide.  

PubMed

Temporins are a family of short antimicrobial peptides (8-17 residues) that mostly show potent activity against Gram-positive bacteria. Herein, we demonstrate that temporin-SHd, a 17-residue peptide with a net charge of +2 (FLPAALAGIGGILGKLF(amide)), expressed a broad spectrum of antimicrobial activity. This peptide displayed potent antibacterial activities against Gram-negative and Gram-positive bacteria, including multi-drug resistant Staphylococcus aureus strains, as well as antiparasitic activity against promastigote and the intracellular stage (amastigote) of Leishmania infantum, at concentration not toxic for the macrophages. Temporin-SHd that is structured in a non-amphipathic ?-helix in anionic membrane-mimetic environments, strongly and selectively perturbs anionic bilayer membranes by interacting with the polar head groups and acyl region of the phospholipids, with formation of regions of two coexisting phases: one phase rich in peptide and the other lipid-rich. The disruption of lipid packing within the bilayer may lead to the formation of transient pores and membrane permeation/disruption once a threshold peptide accumulation is reached. To our knowledge, Temporin-SHd represents the first known 17-residue long temporin expressing such broad spectrum of antimicrobial activity including members of the trypanosomatidae family. Additionally, since only a few shorter members (13 residues) of the temporin family are known to display antileishmanial activity (temporins-TA, -TB and -SHa), SHd is an interesting tool to analyze the antiparasitic mechanism of action of temporins. PMID:23116712

Abbassi, Feten; Raja, Zahid; Oury, Bruno; Gazanion, Elodie; Piesse, Christophe; Sereno, Denis; Nicolas, Pierre; Foulon, Thierry; Ladram, Ali

2013-02-01

214

Antibacterial activities of Groebke-Blackburn-Bienaym? derived imidazo[1,2-a]pyridin-3-amines  

PubMed Central

We sought to explore the imidazo[1,2-a]pyridin-3-amines for TLR7 (or 8)-modulatory activities. This chemotype, readily accessed via the Groebke-Blackburn-Bienaymé multi-component reaction, resulted in compounds that were TLR7/8-inactive, but exhibited bacteriostatic activity against Gram-positive bacteria, including methicillin-resistant S. aureus (MRSA). To investigate the mechanism of antibacterial activity of this new chemotype, a resistant strain of S. aureus was generated by serially passaging the organism in escalating doses of the most active analogue. A comparison of minimum inhibitory concentrations (MICs) of known bacteriostatic agents in wild-type and resistant strains indicates a novel mechanism of action. Structure-activity relationship studies have led to the identification of positions on the scaffold for additional structural modifications that should allow for the introduction of probes designed to examine cognate binding partners and molecular targets, while not significantly compromising antibacterial potency.

Shukla, Nikunj M.; Salunke, Deepak B.; Yoo, Euna; Mutz, Cole A.; Balakrishna, Rajalakshmi; David, Sunil A.

2012-01-01

215

In vitro antibacterial and antifungal activities of Cassia fistula Linn. fruit pulp extracts  

PubMed Central

Aim of the study is to assess the antimicrobial activity Cassia fistula fruit pulp extracts on some bacterial and fungal strains. Hydro alcohol and chloroform extracts of Cassia fistula fruit pulp were evaluated for the potential antimicrobial activity. The antimicrobial activity was determined in both the extracts using the agar disc diffusion method. Extracts were effective on tested microorganisms. The antibacterial and antifungal activities of solvent extracts (5, 25, 50, 100, 250 ?g/mL) of C. fistula were tested against two gram positive, two gram negative human pathogenic bacteria and three fungi, respectively. Crude extracts of C. fistula exhibited moderate to strong activity against most of the bacteria tested. The tested bacterial strains were Staphylococcus aureus, Streptococcus pyogenes, Escherichia coil, Pseudomonas aeruginosa, and fungal strains were Aspergillus. niger, Aspergillus. clavatus, Candida albicans. The antibacterial potential of the extracts were found to be dose dependent. The antibacterial activities of the C. fistula were due to the presence of various secondary metabolites. Hence, these plants can be used to discover bioactive natural products that may serve as leads in the development of new pharmaceuticals research activities.

Bhalodia, N. R.; Nariya, P. B.; Acharya, R. N.; Shukla, V. J.

2012-01-01

216

In vitro antibacterial and antifungal activities of Cassia fistula Linn. fruit pulp extracts.  

PubMed

Aim of the study is to assess the antimicrobial activity Cassia fistula fruit pulp extracts on some bacterial and fungal strains. Hydro alcohol and chloroform extracts of Cassia fistula fruit pulp were evaluated for the potential antimicrobial activity. The antimicrobial activity was determined in both the extracts using the agar disc diffusion method. Extracts were effective on tested microorganisms. The antibacterial and antifungal activities of solvent extracts (5, 25, 50, 100, 250 ?g/mL) of C. fistula were tested against two gram positive, two gram negative human pathogenic bacteria and three fungi, respectively. Crude extracts of C. fistula exhibited moderate to strong activity against most of the bacteria tested. The tested bacterial strains were Staphylococcus aureus, Streptococcus pyogenes, Escherichia coil, Pseudomonas aeruginosa, and fungal strains were Aspergillus. niger, Aspergillus. clavatus, Candida albicans. The antibacterial potential of the extracts were found to be dose dependent. The antibacterial activities of the C. fistula were due to the presence of various secondary metabolites. Hence, these plants can be used to discover bioactive natural products that may serve as leads in the development of new pharmaceuticals research activities. PMID:23049197

Bhalodia, N R; Nariya, P B; Acharya, R N; Shukla, V J

2012-01-01

217

Which antibiotic for resistant Gram-positives, and why?  

PubMed

Increasing resistance in Gram-positive pathogens, particularly Staphylococcus aureus, and enterococcus, has become a major clinical problem, particularly in the hospital environment, causing significant morbidity and mortality in both healthy hosts and in those with underlying comorbidities. Increased resistance drives the use of empiric therapy with less well-studied and potentially more toxic agents. Resistance mechanisms for currently recommended agents are discussed, with options for therapy of resistant pathogens. For any new agent used, resistance is likely to develop, which underscores the concept that both antibiotics and antimicrobial resistance are ancient, and only by prudent use of antimicrobial agents and effective infection control measures when resistance arises, will effective agents be available to treat Gram-positive pathogens in the future. PMID:24188585

Bradley, John S

2014-01-01

218

Antibacterial activity of selected glass ionomer cements.  

PubMed

Introduction: The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus. Material and methods: Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC), Fuji IX (GC), Ketac Molar (3M Espe) and Ketac Silver (3M Espe). Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep) were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Results: Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Discussion: Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation. PMID:24491892

Luczaj-Cepowicz, El?bieta; Marczuk-Kolada, Gra?yna; Zalewska, Anna; Pawi?ska, Ma?gorzata; Leszczy?ska, Katarzyna

2014-01-01

219

Isoflavones as potentiators of antibacterial activity.  

PubMed

Isoflavones isolated from Lupinus argenteus were found to potentiate the antibacterial activity of alpha-linolenic acid, also found in the same plant. The isoflavones also potentiated the activity of the natural plant antibiotic berberine and the synthetic fluoroquinoline antibiotic norfloxacin. The isoflavones increased the uptake of berberine into Staphylococcus aureus cells, indicating that they may be inhibiting a multidrug resistance pump (MDR). Thus, L. argenteus contains a weak antibacterial and also MDR pump inhibitors, which increase its potency. PMID:12952418

Morel, Cécile; Stermitz, Frank R; Tegos, George; Lewis, Kim

2003-09-10

220

ANTIBACTERIAL ACTIVITY OF THYMUS DAENENSIS METHANOLIC EXTRACT  

Microsoft Academic Search

Medicinal plants are potential of antimicrobial compounds. The present study deals with the antibacterial activity of methanolic extract of Thymus daenensis. Aerial parts of the plant were collected from Alvand mountainside (Hamadan, Iran) in May 2005, air-dried and extracted by methanol. The dried extract was redissolved in methanol to make a 100mg\\/ml solution and then filtered. Antibacterial activity of the

FARAZ MOJAB; MAHSHID POURSAEED; HADI MEHRGAN; SHIMA PAKDAMAN

2008-01-01

221

Surface enhanced Raman scattering, antibacterial and antifungal active triangular gold nanoparticles  

NASA Astrophysics Data System (ADS)

Shape controlled syntheses of gold nanoparticles have attracted a great deal of attention as their optical, electronic, magnetic and biological properties are strongly dependent on the size and shape of the particles. Here is a report on the surface enhanced Raman scattering (SERS) activity of Cinnamomum zeylanicum leaf broth reduced gold nanoparticles consisting of triangular and spherical like particles, using 2-aminothiophenol (2-ATP) and crystal violet (CV) as probe molecules. Nanoparticles prepared with a minimum leaf broth concentration, having a greater number of triangular like particles exhibit a SERS activity of the order of 107. The synthesized nanoparticles exhibit efficient antibacterial activity against the tested gram negative bacterium Escherichia coli and gram positive bacterium Staphylococcus aureus. Investigations on the antifungal activity of the synthesized nanoparticles against Aspergillus niger and Fusarium oxysporum positive is also discussed.

Smitha, S. L.; Gopchandran, K. G.

2013-02-01

222

Surface enhanced Raman scattering, antibacterial and antifungal active triangular gold nanoparticles.  

PubMed

Shape controlled syntheses of gold nanoparticles have attracted a great deal of attention as their optical, electronic, magnetic and biological properties are strongly dependent on the size and shape of the particles. Here is a report on the surface enhanced Raman scattering (SERS) activity of Cinnamomum zeylanicum leaf broth reduced gold nanoparticles consisting of triangular and spherical like particles, using 2-aminothiophenol (2-ATP) and crystal violet (CV) as probe molecules. Nanoparticles prepared with a minimum leaf broth concentration, having a greater number of triangular like particles exhibit a SERS activity of the order of 10(7). The synthesized nanoparticles exhibit efficient antibacterial activity against the tested gram negative bacterium Escherichia coli and gram positive bacterium Staphylococcus aureus. Investigations on the antifungal activity of the synthesized nanoparticles against Aspergillus niger and Fusarium oxysporum positive is also discussed. PMID:23220525

Smitha, S L; Gopchandran, K G

2013-02-01

223

Synergistic antibacterial activity of chitosan-silver nanocomposites on Staphylococcus aureus.  

PubMed

The approach of combining different mechanisms of antibacterial action by designing hybrid nanomaterials provides a new paradigm in the fight against resistant bacteria. Here, we present a new method for the synthesis of silver nanoparticles enveloped in the biopolymer chitosan. The method aims at the production of bionanocomposites with enhanced antibacterial properties. We find that chitosan and silver nanoparticles act synergistically against two strains of Gram-positive Staphylococcus aureus (S. aureus). As a result the bionanocomposites exhibit higher antibacterial activity than any component acting alone. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of the chitosan-silver nanoparticles synthesized at 0?°C were found to be lower than those reported for other types of silver nanoparticles. Atomic force microscopy (AFM) revealed dramatic changes in morphology of S. aureus cells due to disruption of bacterial cell wall integrity after incubation with chitosan-silver nanoparticles. Finally, we demonstrate that silver nanoparticles can be used not only as antibacterial agents but also as excellent plasmonic substrates to identify bacteria and monitor the induced biochemical changes in the bacterial cell wall via surface enhanced Raman scattering (SERS) spectroscopy. PMID:21343644

Potara, Monica; Jakab, Endre; Damert, Annette; Popescu, Octavian; Canpean, Valentin; Astilean, Simion

2011-04-01

224

Regulation of nitrogen metabolism in gram-positive bacteria  

Microsoft Academic Search

A search for new members of the TnrA and GlnR regulons, responsible for assimilation of nitrogen in Gram-positive bacteria,\\u000a was performed. Common regulatory signals with consensus sequences ATGTNAWWWWWWWTNACAT and TGTNAWWWWWWWTNACA were identified\\u000a for GlnR and TnrA, respectively. The structure was described and new potential members were found in Bacillus subtilis, B. licheniformis, Geobacillus kaustophilus, and Oceanobacillus iheyensis for the TnrA\\/GlnR

N. A. Doroshchuk; M. S. Gelfand; D. A. Rodionov

2006-01-01

225

Influence of acetylation degree and molecular weight of homogeneous chitosans on antibacterial and antifungal activities.  

PubMed

The results given in the literature are conflicting when considering the relationship between antimicrobial activity and chitosan characteristics. To be able to clarify, we prepared fifteen homogeneous chitosans with different acetylation degrees (DA) and molecular weights (MW) by reacetylation of a fully deacetylated chitin under homogeneous conditions. They were tested at different pH values for their antimicrobial activities against four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella typhi), four Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis and Micrococcus luteus) and three fungi (Aspergillus niger, Fusarium oxysporum and Alternaria solani). Chitosans markedly inhibited growth of most bacteria and fungi tested, although the inhibitory effect depends on the type of microorganism and on the chitosan characteristics (DA and MW) with minimum inhibitory concentrations in the range of 0.001 to 0.1w%. Considering chitosan efficiency on bacteria, our series of data clearly show that the lower DA and the lower pH give the larger efficiency. Antibacterial activity was further enhanced for Gram-negative bacteria with decreasing MW, whereas, opposite effect was observed with the Gram-positive. Concerning the antifungal activity, the influence of chitosan characteristics was dependent on the particular type of fungus. Fungal growth decreased with increasing MW for F. oxysporum and decreasing DA for A. solani, but no MW or DA dependences were observed with A. niger. PMID:24929684

Younes, Islem; Sellimi, Sabrine; Rinaudo, Marguerite; Jellouli, Kemel; Nasri, Moncef

2014-08-18

226

Synthesis and in vitro antibacterial activity of gemifloxacin derivatives containing a substituted benzyloxime moiety.  

PubMed

A series of novel gemifloxacin (GMFX) derivatives containing a substituted benzyloxime moiety with remarkable improvement in lipophilicity were synthesized. The target compounds evaluated for their in vitro antibacterial activity against representative strains. Our results reveal that most of the target compounds have considerable potency against all of the tested gram-positive strains including MRSA and MRSE (MIC: <0.008-8 ?g/mL), although they are generally less active than the references against the gram-negative strains. In particular, compound 11l (MIC: <0.008-4 ?g/mL) was found to be 8-2048 and 2-128 times more potent than levofloxacin (LVFX) and GMFX against the gram-positive strains, respectively. Moreover, against MRSA clinical isolates, 11l (MIC(90): 1 ?g/mL) is 8-fold more active than GMFX, and 2-fold more active than GMFX and moxifloxacin against MRSE clinical isolates (MIC(90): 4 ?g/mL). PMID:22841282

Feng, Lianshun; Lv, Kai; Liu, Mingliang; Wang, Shuo; Zhao, Jing; You, Xuefu; Li, Sujie; Cao, Jue; Guo, Huiyuan

2012-09-01

227

Conjugative type IV secretion systems in Gram-positive bacteria  

PubMed Central

Bacterial conjugation presents the most important means to spread antibiotic resistance and virulence factors among closely and distantly related bacteria. Conjugative plasmids are the mobile genetic elements mainly responsible for this task. All the genetic information required for the horizontal transmission is encoded on the conjugative plasmids themselves. Two distinct concepts for horizontal plasmid transfer in Gram-positive bacteria exist, the most prominent one transports single stranded plasmid DNA via a multi-protein complex, termed type IV secretion system, across the Gram-positive cell envelope. Type IV secretion systems have been found in virtually all unicellular Gram-positive bacteria, whereas multicellular Streptomycetes seem to have developed a specialized system more closely related to the machinery involved in bacterial cell division and sporulation, which transports double stranded DNA from donor to recipient cells. This review intends to summarize the state of the art of prototype systems belonging to the two distinct concepts; it focuses on protein key players identified so far and gives future directions for research in this emerging field of promiscuous interbacterial transport.

Goessweiner-Mohr, Nikolaus; Arends, Karsten; Keller, Walter; Grohmann, Elisabeth

2013-01-01

228

Architecture and assembly of the Gram-positive cell wall  

PubMed Central

The bacterial cell wall is a mesh polymer of peptidoglycan – linear glycan strands crosslinked by flexible peptides – that determines cell shape and provides physical protection. While the glycan strands in thin “Gram-negative” peptidoglycan are known to run circumferentially around the cell, the architecture of the thicker “Gram-positive” form remains unclear. Using electron cryotomography, here we show that Bacillus subtilis peptidoglycan is a uniformly dense layer with a textured surface. We further show it rips circumferentially, curls and thickens at free edges, and extends longitudinally when denatured. Molecular dynamics simulations show that only atomic models based on the circumferential topology recapitulate the observed curling and thickening, in support of an “inside-to-outside” assembly process. We conclude that instead of being perpendicular to the cell surface or wrapped in coiled cables (two alternative models), the glycan strands in Gram-positive cell walls run circumferentially around the cell just as they do in Gram-negative cells. Together with providing insights into the architecture of the ultimate determinant of cell shape, this study is important because Gram-positive peptidoglycan is an important antibiotic target crucial to the viability of several important rod-shaped pathogens including Bacillus anthracis, Listeria monocytogenes, and Clostridium difficile.

Beeby, Morgan; Gumbart, James C.; Roux, Benoit; Jensen, Grant J.

2013-01-01

229

Chemical and antibacterial evaluation of Hypericum triquetrifolium Turra.  

PubMed

Five extracts and pure compounds from the aerial parts of Hypericum triquetrifolium were tested for their antibacterial activity against 31 gram-positive and gram-negative strains using the agar dilution method (Lorian). The ethyl acetate extract exhibited a weak antibacterial activity against Staphylococcus strains, and pure constituents such as quercetin and I3,II8-biapigenin were the active components of this extract. PMID:16220572

Pistelli, Luisa; Bertoli, Alessandra; Morelli, Ivano; Menichini, Francesco; Musmanno, Rosa Anna; Di Maggio, Tiziana; Coratza, Grazietta

2005-09-01

230

Comparative Pharmacokinetics and Pharmacodynamics of the Newer Fluoroquinolone Antibacterials  

Microsoft Academic Search

A number of new fluoroquinolone antibacterials have been released for clin- ical use in recent years. These new agents exhibit enhanced activity against Gram- positive organisms while retaining much of the Gram-negative activity of the earlier agents within the same class. The pharmacokinetics of most of these agents are well described including serum pharmacokinetics, tissue and fluid distribution, and pharmacokinetics

Amir Aminimanizani; Paul Beringer; Roger Jelliffe

2001-01-01

231

Rational Design of Berberine-Based FtsZ Inhibitors with Broad-Spectrum Antibacterial Activity  

PubMed Central

Inhibition of the functional activity of Filamenting temperature-sensitive mutant Z (FtsZ) protein, an essential and highly conserved bacterial cytokinesis protein, is a promising approach for the development of a new class of antibacterial agents. Berberine, a benzylisoquinoline alkaloid widely used in traditional Chinese and native American medicines for its antimicrobial properties, has been recently reported to inhibit FtsZ. Using a combination of in silico structure-based design and in vitro biological assays, 9-phenoxyalkyl berberine derivatives were identified as potent FtsZ inhibitors. Compared to the parent compound berberine, the derivatives showed a significant enhancement of antibacterial activity against clinically relevant bacteria, and an improved potency against the GTPase activity and polymerization of FtsZ. The most potent compound 2 strongly inhibited the proliferation of Gram-positive bacteria, including methicillin-resistant S. aureus and vancomycin-resistant E. faecium, with MIC values between 2 and 4 µg/mL, and was active against the Gram-negative E. coli and K. pneumoniae, with MIC values of 32 and 64 µg/mL respectively. The compound perturbed the formation of cytokinetic Z-ring in E. coli. Also, the compound interfered with in vitro polymerization of S. aureus FtsZ. Taken together, the chemical modification of berberine with 9-phenoxyalkyl substituent groups greatly improved the antibacterial activity via targeting FtsZ.

Sun, Ning; Chan, Fung-Yi; Lu, Yu-Jing; Neves, Marco A. C.; Lui, Hok-Kiu; Wang, Yong; Chow, Ka-Yan; Chan, Kin-Fai; Yan, Siu-Cheong; Leung, Yun-Chung; Abagyan, Ruben; Chan, Tak-Hang; Wong, Kwok-Yin

2014-01-01

232

Rational Design of Berberine-Based FtsZ Inhibitors with Broad-Spectrum Antibacterial Activity.  

PubMed

Inhibition of the functional activity of Filamenting temperature-sensitive mutant Z (FtsZ) protein, an essential and highly conserved bacterial cytokinesis protein, is a promising approach for the development of a new class of antibacterial agents. Berberine, a benzylisoquinoline alkaloid widely used in traditional Chinese and native American medicines for its antimicrobial properties, has been recently reported to inhibit FtsZ. Using a combination of in silico structure-based design and in vitro biological assays, 9-phenoxyalkyl berberine derivatives were identified as potent FtsZ inhibitors. Compared to the parent compound berberine, the derivatives showed a significant enhancement of antibacterial activity against clinically relevant bacteria, and an improved potency against the GTPase activity and polymerization of FtsZ. The most potent compound 2 strongly inhibited the proliferation of Gram-positive bacteria, including methicillin-resistant S. aureus and vancomycin-resistant E. faecium, with MIC values between 2 and 4 µg/mL, and was active against the Gram-negative E. coli and K. pneumoniae, with MIC values of 32 and 64 µg/mL respectively. The compound perturbed the formation of cytokinetic Z-ring in E. coli. Also, the compound interfered with in vitro polymerization of S. aureus FtsZ. Taken together, the chemical modification of berberine with 9-phenoxyalkyl substituent groups greatly improved the antibacterial activity via targeting FtsZ. PMID:24824618

Sun, Ning; Chan, Fung-Yi; Lu, Yu-Jing; Neves, Marco A C; Lui, Hok-Kiu; Wang, Yong; Chow, Ka-Yan; Chan, Kin-Fai; Yan, Siu-Cheong; Leung, Yun-Chung; Abagyan, Ruben; Chan, Tak-Hang; Wong, Kwok-Yin

2014-01-01

233

Antibacterial activity of Cuminum cyminum L. and Carum carvi L. essential oils.  

PubMed

Essential oils extracted by hydrodistillation from fruits of Cuminum cyminum L. and Carum carvi L. were analyzed by gas chromatography (GC) and GC-mass spectrometry (MS). The main components of C. cyminum oil were p-mentha-1,4-dien-7-al, cumin aldehyde, gamma-terpinene, and beta-pinene, while those of the C. carvi oil were carvone, limonene, germacrene D, and trans-dihydrocarvone. Antibacterial activity, determined with the agar diffusion method, was observed against Gram-positive and Gram-negative bacterial species in this study. The activity was particularly high against the genera Clavibacter, Curtobacterium, Rhodococcus, Erwinia, Xanthomonas, Ralstonia, and Agrobacterium, which are responsible for plant or cultivated mushroom diseases worldwide. In general, a lower activity was observed against bacteria belonging to the genus Pseudomonas. These results suggest the potential use of the above essential oils for the control of bacterial diseases. PMID:15631509

Iacobellis, Nicola S; Lo Cantore, Pietro; Capasso, Francesco; Senatore, Felice

2005-01-12

234

Microwave-Assisted Synthesis of Diverse Pyrrolo[3,4-c]quinoline-1,3-diones and Their Antibacterial Activities.  

PubMed

With the aim of developing a general and practical method for library production, a novel and efficient two-phase microwave-assisted cascade reaction between isatins and ?-ketoamides in [Bmim]BF4/toluene was developed for the synthesis of pyrrolo[3,4-c]quinoline-1,3-diones. The features of this methodology are, the use of microwave-assisted rapid synthesis, mild reaction conditions, high yields, operational simplicity, facile product separation, and recyclability. Furthermore, the antibacterial activities of the pyrrolo[3,4-c]quinoline-1,3-dione derivatives produced were evaluated against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus). These derivatives showed antibacterial activities against Gram-positive strains that were at least equivalent to that against Gram-negative strains. Compound 7{3,5} displayed the most potent antibacterial activity against P. aeruginosa (MIC = 0.5 ?g/mL) and greater activity than standard ampicillin (MIC = 1 ?g/mL). Compound 7{4,7} exhibited the best inhibitory activity against E. coli and E. aerogenes (MIC = 1 and 0.5 ?g/mL), compared with the standard ampicillin (both MICs = 1 ?g/mL). The synthesized pyrrolo[3,4-c]quinoline-1,3-diones are expected to be widely used as lead compounds for the development of new antibacterial agents. PMID:24749663

Xia, Likai; Idhayadhulla, Akber; Lee, Yong Rok; Kim, Sung Hong; Wee, Young-Jung

2014-07-14

235

Platelet and Neutrophil Responses to Gram Positive Pathogens in Patients with Bacteremic Infection  

PubMed Central

Background Many Gram-positive pathogens aggregate and activate platelets in vitro and this has been proposed to contribute to virulence. Platelets can also form complexes with neutrophils but little is however known about platelet and platelet-neutrophil responses in bacterial infection. Methodology/Principal Findings We added isolates of Gram-positive bacteria from 38 patients with a bacteremic infection to blood drawn from the same patient. Aggregometry and flow cytometry were used to assess platelet aggregation and to quantify activation of platelets, neutrophils, and platelet-neutrophils complexes (PNCs) induced by the bacteria. Fifteen healthy persons served as controls. Most isolates of Staphylococcus aureus, beta hemolytic streptococci, and Enterococcus faecalis induced aggregation of platelets from their respective hosts, whereas pneumococci failed to do so. S. aureus isolates induced platelet aggregation more rapidly in patients than in controls, whereas platelet activation by S. aureus was lower in patients than in controls. PNCs were more abundant in baseline samples from patients than in healthy controls and most bacterial isolates induced additional PNC formation and neutrophil activation. Conclusion/Significance We have demonstrated for the first time that bacteria isolated from patients with Gram-positive bacteremia can induce platelet activation and aggregation, PNC formation, and neutrophil activation in the same infected host. This underlines the significance of these interactions during infection, which could be a target for future therapies in sepsis.

Johansson, Daniel; Shannon, Oonagh; Rasmussen, Magnus

2011-01-01

236

Antibacterial and antifungal activity of Cassia fistula L.: an ethnomedicinal plant.  

PubMed

Hexane, chloroform, ethyl acetate, methanol and water extracts from the flower of Cassia fistula (an ethnomedicinal plant) were tested against bacteria and fungi. All the extracts exhibited antibacterial activity against Gram-positive organisms with minimum inhibitory concentrations (MIC) between 0.078 and 2.5 mg/ml. Among the Gram-negative bacteria, only Pseudomonas aeruginosa was susceptible to the extracts. Ethyl acetate crude extract was fractionated using chromatographic techniques. A crystal was isolated, which was confirmed as 4-hydroxy benzoic acid hydrate using X-ray crystallography. It exhibited antifungal activity against Trichophyton mentagrophytes (MIC 0.5 mg/ml) and Epidermophyton floccosum (MIC 0.5 mg/ml). PMID:17532583

Duraipandiyan, V; Ignacimuthu, S

2007-07-25

237

Synthesis, antimycobacterial and antibacterial activity of ciprofloxacin derivatives containing a N-substituted benzyl moiety.  

PubMed

We report herein the design and synthesis of a series of novel ciprofloxacin (CPFX) derivatives with remarkable improvement in lipophilicity by introducing a substituted benzyl moiety to the N atom on the C-7 piperazine ring of CPFX. Antimycobacterial and antibacterial activity of the newly synthesized compounds was evaluated. Results reveal that compound 4f has good in vitro activity against all of the tested Gram-positive strains including MRSA and MRSE (MICs: 0.06-32 ?g/mL) which is two to eightfold more potent than or comparable to the parent drug CPFX (MICs: 0.25-128 ?g/mL), Gram-negative bacteria P. aeruginosa (MICs: 0.5-4 ?g/mL) and M. tuberculosis H37Rv ATCC 27294 (MIC: 1 ?g/mL). PMID:22884110

Wang, Shuo; Jia, Xue-Dong; Liu, Ming-Liang; Lu, Yu; Guo, Hui-Yuan

2012-09-15

238

Chemical composition and antibacterial activity of the essential oil of Cordia verbenacea from the Venezuelan Andes.  

PubMed

The essential oil of Cordia verbenacea D.C. (Boraginaceae) that grows in Mérida-Venezuela was obtained by hydrodistillation from the aerial parts of the plant, yielding 0.21%. The oil was analyzed by GC-FID and GC-MS. Thirty one components which made up 94.3% of the oil were identified. The most abundant constituents found were: tricyclene (23.9%), bicyclogermacrene (11.7%), germacrene D (9.9%) and beta-caryophyllene (8.2%). Antibacterial activity determination was carried out according to the disc diffusion assay. Activity against Gram-positive bacteria Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212, at a minimal inhibitory concentration (MIC) of 170 microg/mL and 200 microg/mL, was found. PMID:19768996

Meccia, Gina; Rojas, Luis B; Velasco, Judith; Díaz, Tulia; Usubillaga, Alfredo; Arzola, Juan Carmona; Ramos, Sulymar

2009-08-01

239

Teichoic acids and related cell-wall glycopolymers in Gram-positive physiology and host interactions  

Microsoft Academic Search

Abstract | Most Gram-positive bacteria incorporate membrane- or peptidoglycan-attached carbohydrate-based polymers into their cell envelopes. Such cell-wall glycopolymers (CWGs) often have highly variable structures and have crucial roles in protecting, connecting and controlling the major envelope constituents. Further important roles of CWGs in host-cell adhesion, inflammation and immune activation have also been described in recent years. Identifying and harnessing highly

Christopher Weidenmaier; Andreas Peschel

2008-01-01

240

Assessment of Total Phenolic, Antioxidant, and Antibacterial Activities of Passiflora Species  

PubMed Central

This study focused on total phenolic content (TPC) and antioxidant and antibacterial activities of the leaves and stems of Passiflora quadrangularis, P. maliformis, and P. edulis extracted using three solvents: petroleum ether, acetone, and methanol. The maximum extraction yields of antioxidant components from the leaves and stems were isolated using methanol extracts of P. edulis (24.28%) and P. quadrangularis (9.76%), respectively. Among the leaf extracts, the methanol extract of P. maliformis had the significantly highest TPC and the strongest antioxidant activity, whereas among the stem extracts, the methanol extract of P. quadrangularis showed the highest phenolic amount and possessed the strongest antioxidant activity. The antibacterial properties of the Passiflora species were tested using the disc diffusion method against 10 human pathogenic bacteria. The largest inhibition zone was observed for the methanol extract of P. maliformis against B. subtilis. Generally, extracts from the Passiflora species exhibit distinct inhibition against Gram-positive but not Gram-negative bacteria. Based on the generated biplot, three clusters of bacteria were designated according to their performance towards the tested extracts. The present study revealed that methanol extracts of the Passiflora contain constituents with significant phenolic, antioxidant, and antibacterial properties for pharmaceutical and nutraceutical uses.

Ramaiya, Shiamala Devi; Bujang, Japar Sidik; Zakaria, Muta Harah

2014-01-01

241

Chemical, spectroscopic characterization, DFT studies and antibacterial activities in vitro of a new gold(I) complex with rimantadine  

NASA Astrophysics Data System (ADS)

A novel gold(I) complex with rimantadine (RTD) was obtained and structurally characterized by a set of chemical and spectroscopic analysis. 1H, 13C and 15N nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic measurements suggest coordination of the ligand to Au(I) through the N atom of the ethanamine group. Theoretical (DFT) calculations confirmed the IR assignments and permit proposing an optimized geometry for the complex. The gold(I)-rimantadine complex (Au-RTD) is soluble in methanol, ethanol, dimethylsulfoxide, acetone and acetonitrile. The preliminary kinetic studies based on UV-vis spectroscopic measurements indicate the stability of the compound in solution. Antibacterial activities of the complex were evaluated by an antibiogram assay. The Au-RTD complex showed an effective in vitro antibacterial activity against the Pseudomonas aeruginosa, Escherichia coli (Gram-negative), and Staphylococcus aureus (Gram-positive) bacterial strains.

Sucena, Suelen F.; Paiva, Raphael E. F.; Abbehausen, Camilla; Mattos, Ives B.; Lancellotti, Marcelo; Formiga, André L. B.; Corbi, Pedro P.

2012-04-01

242

Synthesis, spectroscopic characterization and antibacterial activity of new cobalt(II) complexes of unsymmetrical tetradentate (OSN2) Schiff base ligands.  

PubMed

Cobalt ion complexes with the Schiff bases, (4-X-2-{[2-(2-pyridine-2-yl-ethylsulfanyl)ethylimino]methyl}phenol (X=methoxy (OMe), phenylazo (N(2)Ph), bromo (Br), nitro (NO(2))),were synthesized and investigated by several techniques using elemental analysis (C, H, N), FTIR, electronic spectra and molar conductivity. The thermal stability of free ligands and related cobalt complexes were studied by using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). Cyclic voltammetry indicates that the investigated cobalt complexes, under the experimental conditions, have irreversible redox behavior. The synthesized compounds have antibacterial activity against the four Gram-positive bacteria: Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus and Bacillus anthracis and also against the two Gram-negative bacteria: Klebsiella pneumoniae and Pseudomonas aeruginosa. The activity data show that the parent Schiff bases are more potent antibacterials than the cobalt complexes. PMID:19608303

Saghatforoush, Lotf Ali; Chalabian, Firoozeh; Aminkhani, Ali; Karimnezhad, Ghasem; Ershad, Sohrab

2009-11-01

243

Antibacterial activity of eight Brazilian annonaceae plants.  

PubMed

Sixteen extracts, obtained from eight Brazilian plants of Annonaceae family, were screened for their antibacterial activity: Xylopia frutescens, X. aromatica, X. amazonica, X. benthamii, Annona ambotay, A. crassiflora, A. muricata and A. cherimolia. Amongst the investigated extracts, six showed antibacterial activity against at least one of the tested organisms at the concentration of 100 microg/mL. The most active extracts were those prepared from X. frutescens, X. amazonica, and A. ambotay. A phytochemical screening showed the presence of anonaceus acetogenins in some active extracts. Eleven diterpenoids were also tested for comparison purposes. Six were natural products, previously isolated from Xylopia sp. (kaurenoic, frutoic, xylopic, 15beta-hydroxy-kaurenoic and trachylobanic acids plus kaurenol) and five were derivatives of such compounds, obtained by esterification or reduction reactions. Trachylobanic acid showed antibacterial activity against B. subtilis and S. aureus. PMID:16286303

Takahashi, Jacqueline A; Pereira, Cássia R; Pimenta, Lúcia P S; Boaventura, Maria Amélia D; Silva, Luiz G F E

2006-01-01

244

Nisin inhibits several gram-positive, mastitis-causing pathogens.  

PubMed

Organisms known to cause bovine mastitis, Enterococcus faecalis ssp. liquefaciens ATCC 27959, Staphylococcus aureus ATCC 29740, Streptococcus agalactiae ATCC 27956, Streptococcus equinus ATCC 27960, Streptococcus dysgalactiae ATCC 27957, Streptococcus uberis ATCC 27958, and the neotype Staphylococcus epidermidis ATCC 14990 were examined for their susceptibility to the small peptide antibiotic, nisin. Using a disc assay, minimum inhibitory concentrations of nisin ranged from 10 to 250 micrograms/ml among the strains. Examination of the antimicrobial effect of 50 micrograms/ml nisin in milk showed nisin inhibited all gram-positive pathogens tested. PMID:2516858

Broadbent, J R; Chou, Y C; Gillies, K; Kondo, J K

1989-12-01

245

[Regulation of nitrogen metabolism in gram-positive bacteria].  

PubMed

We searched for new members of the TnrA and GlnR regulons controlling assimilation of nitrogen in gram-positive bacteria. We identified the regulatory signals for these transcription factors with consensuses ATGTNAWWWWWWWTNACAT for GlnR and TGTNAWWWWWWWTNACA for TnrA. We described the structure and found new potential members for the TnrA/GlnR regulons in Bacillus subtilis, B. licheniformis, Geobacillus kaustophilus, Oceanobacillus iheyensis, for the TnrA regulon in B. halodurans and for the GlnR regulons in Lactococcus lactis, Lactobacillus plantarum, Streptococcus pyogenes, S. pneumoniae, S. mutans, S. agalactiae, Enterococcus faecalis, Listeria monocytogenes, Staphylococcus aureus and St. epidermidis. PMID:17086994

Doroshchuk, N A; Gel'fand, M S; Rodionov, D A

2006-01-01

246

Antibacterial compounds from the flowers of Alangium salviifolium.  

PubMed

1-Methyl-1H-pyrimidine-2,4-dione and 3-O-beta-D-glucopyranosyl-(24beta)-ethylcholesta-5,22,25-triene, isolated from the flowers of Alangium salviifolium, showed remarkable antibacterial activities against a number of Gram-positive and Gram-negative bacterial species. PMID:12385881

Anjum, Adeeba; Ekramul Haque, M; Mukhlesur Rahman, M; Sarker, Satyajit D

2002-10-01

247

Antibacterial Effect of the Adhering Human Lactobacillus acidophilus Strain LB  

Microsoft Academic Search

The spent culture supernatant of the human Lactobacillus acidophilus strain LB produces an antibacterial activity against a wide range of gram-negative and gram-positive pathogens. It decreased the in vitro viability of Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium, Shigella flexneri, Escherichia coli, Kleb- siella pneumoniae, Bacillus cereus, Pseudomonas aeruginosa, and Enterobacter spp. In contrast, it did not inhibit lactobacilli and bifidobacteria.

MARIE-HELENE COCONNIER; VANESSA LIEVIN; MARIE-FRANCOISE BERNET-CAMARD; SYLVIE HUDAULT; ALAIN L. SERVIN

1997-01-01

248

Antibacterial activity of the essential oil from Ferula gummosa seed.  

PubMed

Antibacterial activity of Ferula gummosa essential oil was studied against bacterial laboratory ATCC standards using the disk diffusion method. The results showed activity against Gram(+) bacteria and Escherichia coli. Little antibacterial activity was found against Pseudomonas aeruginosa. PMID:15567258

Eftekhar, Fereshteh; Yousefzadi, Morteza; Borhani, K

2004-12-01

249

New N-substituted 7-aminocephalosporanic acid derivatives as potential agents against Streptococcus pneumoniae. Synthesis and in vitro activity  

Microsoft Academic Search

The synthesis and the antimicrobial properties of a new series of cephalosporinic ?-lactam antibiotics is described. The data reported in the present paper show the potential of this type of substituted cephalosporins as new anti Gram-positive antibiotic drugs. In fact, all compounds tested showed a good in vitro antibacterial activity against the most relevant Gram-positive pathogens including resistant species that

Aldo Balsamo; Silvia Barontini; Federico Calvani; Daniela Gentili; Marco Macchia; Armando Rossello; Enza Di Modugno; Antonio Felici

1999-01-01

250

Application of Baranyi function to model the antibacterial properties of solvent extract from Irish York cabbage against food spoilage and pathogenic bacteria  

Microsoft Academic Search

Cabbage is a rich source of a number of bioactive compounds such as flavonoids, glucosinolates and their breakdown products which may have antibacterial, antioxidant and anticancer properties. Outer green leaves of York cabbage were extracted with 60% methanol, ethanol or acetone. Antibacterial activities of vacuum dried crude extracts were estimated against a number of Gram-positive and Gram-negative food spoilage and

Amit K. Jaiswal; S. Gupta; Nissreen Abu-Ghannam; Sabrina Cox

2011-01-01

251

Study on antibacterial activity of chemically synthesized PANI-Ag-Au nanocomposite  

NASA Astrophysics Data System (ADS)

Pristine polyaniline (PANI), PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites have been successfully synthesized by chemical oxidative polymerization method using aniline as monomer, ammonium persulphate as oxidant and metal (Ag, Au and Ag-Au) colloids. UV-Vis analysis exhibited surface Plasmon resonances of Ag, Au, Ag-Au nanoparticles. FT-IR spectra revealed the shift in peak position of N-H stretching. X-ray diffraction (XRD) results confirm the presence of Ag, Au and Au-Ag nanoparticles. HR-TEM images show nanosizes of Ag, Au, Ag-Au and the incorporation of such nanoparticles into the PANI matrix. Pristine PANI, PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites were tested for antibacterial activity by agar well diffusion method. PANI-Ag-Au nanocomposite exhibited higher antibacterial activity against both gram-positive [Streptococcus sp. (MTCC 890), Staphylococcus sp. (MTCC 96)] and gram-negative bacteria [Escherichia coli (MTCC 1671) and Klebsiella sp. (MTCC 7407)] when compared with PANI-Ag nanocomposite, PANI-Au nanocomposite and pristine PANI. The novelty of this study is the polymer-bimetal synthesis and its antibacterial potential.

Boomi, Pandi; Prabu, Halliah Gurumallesh; Manisankar, Paramasivam; Ravikumar, Sundaram

2014-05-01

252

Microplate assay for screening the antibacterial activity of Schiff bases derived from substituted benzopyran-4-one  

NASA Astrophysics Data System (ADS)

Schiff bases (SB1-SB3) were synthesized from the condensation of 6-formyl-7-hydroxy-5-methoxy-2-methylbenzopyran-4-one with 2-aminopyridine (SB1), p-phenylenediamine (SB2) and o-phenylenediamine (SB3), while Schiff bases (SB4-SB6) were synthesized by condensation of 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one with 2-aminopyridine (SB4), p-phenylenediamine (SB5) and o-phenylenediamine (SB6). Schiff bases were characterized using elemental analysis, IR, UV-Vis, 1H NMR, 13C NMR and mass spectroscopy. These compounds were screened for antibacterial activities by micro-plate assay technique. Escherichia coli and Staphylococcus capitis were exposed to different concentrations of the Schiff bases. Results showed that the antibacterial effect of these Schiff bases on Gram-negative bacteria were higher than that on Gram-positive bacteria moreover, the Schiff bases containing substituent OCH3 on position five have higher antibacterial activity than that containing hydroxy group on the same position.

Amin, Rehab M.; Abdel-Kader, Nora S.; El-Ansary, Aida L.

253

Antibacterial activity of Veronica montana L. extract and of protocatechuic acid incorporated in a food system.  

PubMed

This study was designed to evaluate the antibacterial activity of the Veronica montana L. water extract and its main phenolic compound, protocatechuic acid. The antibacterial activity was determined by microdilution assay against six strains of Gram-positive and Gram-negative bacteria. Listeria monocytogenes was the most sensitive of the tested bacterial species. Antibacterial preserving properties of protocatechuic acid were also evaluated after its incorporation in cream cheese, using L. monocytogenes as commonly cheese contaminant. The compound successfully inhibited L. monocytogenes development in cream cheese, at room temperature and in refrigerator (25°C and 4°C, respectively), after 3days of inoculation. Sensory evaluation was carried out in order to validate the mentioned food system. A possible mode of action of the tested compound towards bacterial cells was assessed and appears to be direct lysis of pathogenic cytoplasmic membrane. Prediction of pharmacokinetic properties was also performed using computational analyzes. The obtained results can serve as an important platform for the development of effective natural preservatives. PMID:23333716

Stojkovi?, Dejan S; Zivkovi?, Jelena; Sokovi?, Marina; Glamo?lija, Jasmina; Ferreira, Isabel C F R; Jankovi?, Teodora; Maksimovi?, Zoran

2013-05-01

254

Microplate assay for screening the antibacterial activity of Schiff bases derived from substituted benzopyran-4-one.  

PubMed

Schiff bases (SB(1)-SB(3)) were synthesized from the condensation of 6-formyl-7-hydroxy-5-methoxy-2-methylbenzopyran-4-one with 2-aminopyridine (SB(1)), p-phenylenediamine (SB(2)) and o-phenylenediamine (SB(3)), while Schiff bases (SB(4)-SB(6)) were synthesized by condensation of 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one with 2-aminopyridine (SB(4)), p-phenylenediamine (SB(5)) and o-phenylenediamine (SB(6)). Schiff bases were characterized using elemental analysis, IR, UV-Vis, (1)H NMR, (13)C NMR and mass spectroscopy. These compounds were screened for antibacterial activities by micro-plate assay technique. Escherichia coli and Staphylococcus capitis were exposed to different concentrations of the Schiff bases. Results showed that the antibacterial effect of these Schiff bases on Gram-negative bacteria were higher than that on Gram-positive bacteria moreover, the Schiff bases containing substituent OCH(3) on position five have higher antibacterial activity than that containing hydroxy group on the same position. PMID:22591797

Amin, Rehab M; Abdel-Kader, Nora S; El-Ansary, Aida L

2012-09-01

255

Antibacterial activity of Pd(II) complexes with salicylaldehyde-amino acids Schiff bases ligands.  

PubMed

Palladium(II) complexes with Schiff bases ligands derived from salicylaldehyde and amino acids (Ala, Gly, Met, Ser, Val) have been synthesized and characterized by Fourier transform (FT)-IR, UV-Vis and (1)H-NMR spectroscopy. The electrospray mass spectrometry (ES-MS) spectrometry confirms the formation of palladium(II) complexes in 1/2 (M/L) molar ratio. All the Pd(II) complexes 1, [Pd(SalAla)2]Cl2; 2, [Pd(SalGly)2]Cl2; 3, [Pd(SalMet)2]Cl2; 4, [Pd(SalSer)2]Cl2; 5, [Pd(SalVal)2]Cl2; have shown antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. PMID:24390488

Rîmbu, Cristina; Danac, Ramona; Pui, Aurel

2014-01-01

256

Bioinspired synthesis of highly stabilized silver nanoparticles using Ocimum tenuiflorum leaf extract and their antibacterial activity  

NASA Astrophysics Data System (ADS)

Biosynthesis of nanoparticles is under exploration due to wide biomedical applications and research interest in nanotechnology. We herein reports bioinspired synthesis of silver nanoparticles with the aid of novel, non toxic ecofriendly biological material namely Ocimum tenuiflorum leaf extract. It acts as reducing as well as stabilizing agent. An intense surface plasmon resonance band at ˜450 nm in the UV-visible spectrum clearly reveals the formation of silver nanoparticles. The photoluminescence spectrum was recorded to study excitation and emission. TEM and PSD by dynamic light scattering studies showed that size of silver nanoparticles to be in range 25-40 nm. Face centered cubic structure of silver nanoparticles are confirmed by SAED pattern. The charge on synthesized silver nanoparticles was determined by zeta potential. The colloidal solution of silver nanoparticles were found to exhibit high antibacterial activity against three different strains of bacteria Escherichia coli (Gram negative), Corney bacterium (gram positive), Bacillus substilus (spore forming).

Patil, Rupali S.; Kokate, Mangesh R.; Kolekar, Sanjay S.

2012-06-01

257

Composition of the essential oil of Bidens tripartita L. roots and its antibacterial and antifungal activities.  

PubMed

The chemical composition of the essential oil obtained from the roots of Bidens tripartita L. by hydrodistillation was investigated by gas chromatography-mass spectrometry. In total, 106 compounds were identified (97.1% of the total oil). The main components of the oil were ?-pinene (15.0%), ?-bisabolene (9.3%), p-cymene (6.0%), hexanal (5.7%), linalool (4.6%), p-cymene-9-ol (3.4%), ?-elemene (2.6%), 2-pentylfuran (2.2%), and silphiperfol-6-ene (2.1%). The antibacterial and antifungal properties of the essential oil were evaluated against eight Gram-positive and 11 Gram-negative bacterial species and 10 fungal strains. The oil exhibited a strong antifungal activity. PMID:21370967

Tomczykowa, Monika; Leszczy?ska, Katarzyna; Tomczyk, Micha?; Tryniszewska, El?bieta; Kalemba, Danuta

2011-04-01

258

Antibacterial activity-guided purification and identification of a novel C-20 oxygenated ent-kaurane from Rabdosia serra (MAXIM.) HARA.  

PubMed

The objective of this work was to conduct an activity-guided isolation of antibacterial compounds from Rabdosia serra. The ethanol extracts of R. serra leaf and stem were partitioned sequentially into petroleum ether, ethyl acetate, butanol and water fractions, respectively. The ethanol extract of leaf evidenced broad-spectrum antibacterial activity against gram-positive bacterial, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes. The ethyl acetate fractions of leaf and stem exhibited strong inhibition against gram-positive bacteria, and were then purified further. On the basis of antibacterial assay-guided purification, three phenolic compounds (rosmarinic acid, methyl rosmarinate and pedalitin) and four C-20 oxygenated ent-kauranes (effusanin E, lasiodin, rabdosichuanin D and a new compound namely effusanin F) were obtained, whose contents were determined by HPLC analysis. The broth microdilution method confirmed the important inhibition potential of C-20 oxygenated ent-kauranes with low minimum inhibitory concentration (MIC) values. Effusanin E, lasiodin and effusanin F could be useful for the development of new antibacterial agents. PMID:23561188

Lin, Lianzhu; Zhu, Dashuai; Zou, Linwu; Yang, Bao; Zhao, Mouming

2013-08-15

259

Type IV pili in Gram-positive bacteria.  

PubMed

Type IV pili (T4P) are surface-exposed fibers that mediate many functions in bacteria, including locomotion, adherence to host cells, DNA uptake (competence), and protein secretion and that can act as nanowires carrying electric current. T4P are composed of a polymerized protein, pilin, and their assembly apparatuses share protein homologs with type II secretion systems in eubacteria and the flagella of archaea. T4P are found throughout Gram-negative bacterial families and have been studied most extensively in certain model Gram-negative species. Recently, it was discovered that T4P systems are also widespread among Gram-positive species, in particular the clostridia. Since Gram-positive and Gram-negative bacteria have many differences in cell wall architecture and other features, it is remarkable how similar the T4P core proteins are between these organisms, yet there are many key and interesting differences to be found as well. In this review, we compare the two T4P systems and identify and discuss the features they have in common and where they differ to provide a very broad-based view of T4P systems across all eubacterial species. PMID:24006467

Melville, Stephen; Craig, Lisa

2013-09-01

260

Benfang Lei's research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis  

PubMed Central

Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS) and horse pathogen Streptococcus equi (S. equi). His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S. equi pathogenesis. Heme is an important source of essential iron for bacterial pathogens. Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS, demonstrated direct heme transfer from one protein to another, demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system, elucidated the activated heme transfer mechanism, and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction. These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Gram-positive pathogens. Pathogenesis of GAS is mediated by an abundance of extracellular proteins, and pathogenic role and functional mechanism are not known for many of these virulence factors. Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination. These studies may lead to development of novel strategies to prevent and treat GAS infections.

Lei, Benfang

2010-01-01

261

Antibacterial activity and the histopathological study of crude extracts and isolated tecomine from Tecoma stans Bignoniaceae in Iraq  

PubMed Central

Background: Tecoma stans (Bignoniaceae) is a central and south American tree used for the control of diabetes, also known as Yellow Elder, it was collected from the gardens of Al-Jadria in Iraq. Materials and Methods: One of the main reported alkaloidal constituents, tecomine, was isolated and confirmed by spectral analysis. The bacteriological assay for different plant leaves extracts; aqueous, ethanolic, and isolated tecomine were conducted to evaluate the antibacterial effect against gram-negative and gram-positive bacteria. Results: Whole alcoholic and aqueous extract exhibited the antibacterial activity and isolated tecomine. Histopathological evaluation was demonstrated on the liver, spleen, and pancreas of the BALB/c mice given the whole alcoholic and aqueous extract that showed no significant changes in the organ texture. Conclusion: Biochemical analysis of the serum obtained showed decrease in the glucose level in the mice treated with plant extract at the most two higher concentrations used with no change in the cholesterol and triglyceride level.

Al-Azzawi, Amad M.; Al-Khateeb, Ekbal; Al-Sameraei, Kulood; Al-Juboori, Alyaa G

2012-01-01

262

Ligand-exchangeability of 2-coordinate phosphinegold(I) complexes with AuSP and AuNP cores showing selective antimicrobial activities against Gram-positive bacteria. Crystal structures of [Au(2-Hmpa)(PPh 3)] and [Au(6-Hmna)(PPh 3)] (2-H 2mpa=2-mercaptopropionic acid, 6-H 2mna=6-mercaptonicotinic acid)  

Microsoft Academic Search

Selective and effective antimicrobial activities against Gram-positive bacteria (B. subtilis and\\/or S. aureus) were found in 2-coordinate gold(I)–PPh3 complexes with AuSP and AuNP cores, i.e. [Au(L)(PPh3)] (HL=2-H2mna [H2mna=mercaptonicotinic acid] 3, d-H2pen [H2pen=penicillamine] 4, d,l-H2pen 5, 4-H2mba [H2mba=mercaptobenzoic acid] 8, Hpz [Hpz=pyrazole] 9, Him [Him=imidazole] 10, 1,2,3-Htriz [Htriz=triazole] 11, 1,2,4-Htriz 12, Htetz [Htetz=tetrazole] 13), whereas no activity was observed in 2-coordinate

Kenji Nomiya; Satoshi Yamamoto; Ryusuke Noguchi; Hironari Yokoyama; Noriko Chikaraishi Kasuga; Kei Ohyama; Chieko Kato

2003-01-01

263

Electrospun chitosan nanofibers with controlled levels of silver nanoparticles. Preparation, characterization and antibacterial activity.  

PubMed

The ideal wound dressing would have properties that allow for absorption of exudates, and inhibition of microorganism for wound protection. In this study, we utilized an electrospinning (ELSP) technique to design a novel wound dressing. Chitosan (CTS) nanofibers containing various ratios of silver nanoparticles (AgNPs) were obtained. AgNPs were generated directly in the CTS solution by using a chemical reduction method. The formation and presence of AgNPs in the CTS/AgNPs composite was confirmed by x-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV) and thermogravimetric analysis (TGA). The electrospun CTS/AgNPs nanofibers were characterized morphologically by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These nanofibers were subsequently tested to evaluate their antibacterial activity against gram-negative Pseudomonas aeruginosa (P. aeruginosa) and gram-positive Methicillin-resistant Staphylococcus aureus (MRSA). Results of this antibacterial testing suggest that CTS/AgNPs nanofibers may be effective in topical antibacterial treatment in wound care. PMID:25037384

Lee, Sang Jin; Heo, Dong Nyoung; Moon, Ji-Hoi; Ko, Wan-Kyu; Lee, Jung Bok; Bae, Min Soo; Park, Se Woong; Kim, Ji Eun; Lee, Dong Hyun; Kim, Eun-Cheol; Lee, Chang Hoon; Kwon, Il Keun

2014-10-13

264

Nitric oxide integrated polyethylenimine-based tri-block copolymer for efficient antibacterial activity.  

PubMed

The work demonstrated a successful synthesis of nitric oxide (NO)-releasing material and its antibacterial effect on Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA). The polymeric support composed of thermosensitive Pluronic F68 having good biocompatibility and branched polyethylenimine (BPEI) housed N-diazeniumdiolates (NONOates) which could store and release NO under appropriate physiological condition. The developed F68-BPEI-NONOates releases a sufficient amount of NO under physiological condition to elicit effective killing of E. coli, S. aureus and MRSA. The antibacterial ability of the released NO was compared to untreated control or unmodified F68 polymer by using confocal microscopy; F68-BPEI-NONOates demonstrated excellent antibacterial activity with in vitro low cytotoxicity. TEM investigation also revealed the destruction of bacteria membrane caused by NO. The effectiveness of F68-BPEI-NONOates against resistant strains such as MRSA provides a very simple but highly efficient strategy to combat drug-resistant bacterial infections. PMID:23932499

Park, Junghong; Kim, Jihoon; Singha, Kaushik; Han, Dong-Keun; Park, Hansoo; Kim, Won Jong

2013-11-01

265

Antibacterial activity of Pulicaria dysenterica extracts.  

PubMed

Aqueous, methanolic and chloroformic extracts of Pulicaria dysenterica aerial parts were tested for their antibacterial activity using the disc-diffusion assay technique. The methanolic extract was found to be the most effective extract against three out of six tested bacteria. All of the extracts were active against Vibrio cholera. PMID:12781813

Nickavar, Bahman; Mojab, Faraz

2003-06-01

266

Mercury(II) complexes of unsymmetric phosphorus ylides: Synthesis, spectroscopic and antibacterial activity studies  

NASA Astrophysics Data System (ADS)

The reaction of Ph2PCH2PPh2 (dppm) with 2-bromo-3-nitroacetophenone and 2,2?,4?-trichloroacetophenone in chloroform produce the new phosphonium salts [Ph2PCH2PPh2CH2C(O)C6H4NO2]Br (1) and [Ph2PCH2PPh2CH2C(O)C6H3Cl2]Cl (2). Further, by reaction of the monophosphonium salts of dppm with the strong base triethylaminethe corresponding bidentate phosphorus ylides, Ph2PCH2PPh2C(H)C(O)C6H4NO2 (3) and Ph2PCH2PPh2C(H)C(O)C6H3Cl2 (4) were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX2[(Ph2PCH2PPh2C(H)C(O)C6H4NO2)]} [X = Cl (5), Br (6), I (7)] and {HgX2[(Ph2PCH2PPh2C(H)C(O)C6H3Cl2)]} [X = Cl (8), Br (9), I (10)]. Characterization of the obtained compounds was performed by elemental analysis, IR, 1H, 31P and 13C NMR. The structure of compound 1 being unequivocally determined by single crystal X-ray diffraction techniques. The mass spectrum of compound 6 (as an instance) also demonstrates the synthesize of these compounds. In all complexes the title ylides are coordinated through the ylidic carbon and the phosphine atom. These compounds form five membered ring under complexation. The antibacterial effects of DMSO solutions of the ligands and their metal complexes were evaluated by the disc diffusion method against six Gram positive and negative bacteria. All compounds represent antibacterial activity against these bacteria with high levels of inhibitory potency exhibited against the Gram positive species.

Sabounchei, Seyyed Javad; Panahimehr, Mohammad; Hosseinzadeh, Marjan; Karamian, Roya; Asadbegy, Mostafa; Masumi, Azadeh

2014-03-01

267

Antibacterial activity of some indigenous plants used for the treatment of wounds in the Eastern Cape, South Africa.  

PubMed

The use of medicinal plants in the world, and especially in South Africa, contributes significantly to primary health care. This paper presents the findings of an initial survey of plants used for the treatment of wounds in the Eastern Cape Province, South Africa. Ethnomedical information gathered from surveys at clinics, hospitals as well as interviews with traditional healers and rural dwellers has revealed that Grewia occidentalis, Polystichum pungens, Cheilanthes viridis and Malva parvifolia are the most commonly used plants for the treatment of wounds in the province. The methanol extracts of G. occidentalis, P. pungens and C. viridis showed significant inhibition against gram-positive and gram-negative bacteria, while the acetone extract of P. pungens inhibited the gram-positive bacteria only. Extracts from M. parvifolia did not show any antibacterial activity at 5.0 mg/ml. Generally, the antibacterial property of the plants appears to have justified their use for the treatment of wounds, which are contaminated through bacterial infection, in the province. PMID:10432215

Grierson, D S; Afolayan, A J

1999-07-01

268

New thermosensitive plasmid for gram-positive bacteria.  

PubMed Central

We isolated a replication-thermosensitive mutant of the broad-host-range replicon pWV01. The mutant pVE6002 is fully thermosensitive above 35 degrees C in both gram-negative and gram-positive bacteria. Four clustered mutations were identified in the gene encoding the replication protein of pVE6002. The thermosensitive derivative of the related plasmid pE194 carries a mutation in the analogous region but not in the same position. Derivatives of the thermosensitive plasmid convenient for cloning purposes have been constructed. The low shut-off temperature of pVE6002 makes it a useful suicide vector for bacteria which are limited in their own temperature growth range. Using pVE6002 as the delivery vector for a transposon Tn10 derivative in Bacillus subtilis, we observed transposition frequencies of about 1%. Images

Maguin, E; Duwat, P; Hege, T; Ehrlich, D; Gruss, A

1992-01-01

269

Coordinate regulation of Gram-positive cell surface components  

PubMed Central

The cell surface of Gram-positive pathogens represents a complex association of glycopolymers that control cell division, homeostasis, immune evasion, tissue invasion, and resistance to antimicrobials. These glycopolymers include the peptidoglycan cell wall, wall-teichoic acids, lipoteichoic acids, and capsular polysaccharide. Disruption of individual factors often results in pleiotropic effects, making it difficult to discern regulation and function. In this review we collate recent work describing these pleiotropic phenotypes, and propose that this is due to coordinated regulation of biosynthesis or modification of these cell surface components. A better understanding of the regulatory networks that control the relative prevalence of each factor on the cell surface or their modulated functions may help facilitate the identification of new targets for antimicrobial therapy.

Hanson, Brett R.; Neely, Melody N.

2012-01-01

270

Antibacterial activity of propolis against Staphylococcus aureus.  

PubMed

In the present study, antimicrobial activity of the ethanolic extract of propolis (EEP), collected at different periods (June, August, and October-November) from various regions (Taipei, Mingchien, and Fanglia) in Taiwan, against Staphylococcus aureus was investigated. The effects of cell age, incubation temperature, and pH in response to EEP were also investigated. Depending on concentration, collecting area, and time, EEP exerted various degrees of antibacterial activity against S. aureus. The minimum inhibitory concentration of EEP tested ranged from <3.75 to 60 microg/ml, while the minimum bactericidal concentration ranged between 7.5 and 120 microg/ml against S. aureus. In general, a higher antibacterial activity was noted with EEP collected in August than other months. EEP of Mingchien-6 showed the most profound antibacterial activity among the EEP samples tested. The age of a bacterial culture affected its susceptibility to EEP. Cells in the late-exponential phase were most susceptible to EEP. Higher temperature (37 degrees C) and acidic pH enhanced the antibacterial activity of EEP. PMID:15992620

Lu, Li-Chang; Chen, Yue-Wen; Chou, Cheng-Chun

2005-07-15

271

The human Lactobacillus acidophilus strain LA1 secretes a nonbacteriocin antibacterial substance(s) active in vitro and in vivo.  

PubMed Central

The adhering human Lactobacillus acidophilus strain LA1 inhibits the cell association and cell invasion of enteropathogens in cultured human intestinal Caco-2 cells (M. F. Bernet, D. Brassard, J. R. Neeser, and A. L. Servin, Gut 35:483-489, 1994). Here, we demonstrate that strain LA1 developed its antibacterial activity in conventional or germ-free mouse models orally infected by Salmonella typhimurium. We present evidence that the spent culture supernatant of strain LA1 (LA1-SCS) contained antibacterial components active against S. typhimurium infecting the cultured human intestinal Caco-2 cells. The LA1-SCS antibacterial activity was observed in vitro against a wide range of gram-negative and gram-positive pathogens, such as Staphylococcus aureus, Listeria monocytogenes, S. typhimurium, Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter cloacae. By contrast, no activity was observed against species of the normal gut flora, such as lactobacilli and bifidobacteria. The LA1-SCS antibacterial activity was insensitive to proteases and independent of lactic acid production.

Bernet-Camard, M F; Lievin, V; Brassart, D; Neeser, J R; Servin, A L; Hudault, S

1997-01-01

272

Peptoid analogues of anoplin show antibacterial activity.  

PubMed

We have synthesised nine analogues of the antibacterial peptide anoplin with a peptoid residue at position 5 (H-GLLKXIKTLL-NH(2)). The most active compounds showed MIC-values of 12.5 and 25 microM against E.coli and S.aureus. These MIC-values are comparable with anoplin which showed 23 microM and 11 microM against E. coli and S.aureus. However, the selectivity was reversed. Our results indicate that peptoid analogues of anoplin are promising lead structures for developing new antibacterial agents. PMID:19799550

Meinike, K; Hansen, P R

2009-01-01

273

Studies on the antibacterial activity of dodecylglycerol  

Microsoft Academic Search

The antimicrobial activity of lipids has been known for many years, with dodecanoylglycerol (dodecanoic acid esterified to glycerol) being one of the most potential. However, the antibacterial potency of dodecylglycerol (DDG), the corresponding 1-O-alkyl glycerol ether, is considerably greater. The superior efficacy of DDG can be attributed, at least in part, to the greater chemical and metabolic stability of the

Brissette

1985-01-01

274

In vitro activity of ceftaroline-avibactam against gram-negative and gram-positive pathogens isolated from patients in Canadian hospitals from 2010 to 2012: results from the CANWARD surveillance study.  

PubMed

The in vitro activities of ceftaroline-avibactam, ceftaroline, and comparative agents were determined for a collection of bacterial pathogens frequently isolated from patients seeking care at 15 Canadian hospitals from January 2010 to December 2012. In total, 9,758 isolates were tested by using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method (document M07-A9, 2012), with MICs interpreted by using CLSI breakpoints (document M100-S23, 2013). Ceftaroline-avibactam demonstrated potent activity (MIC90, ? 0.5 ?g/ml) against Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Morganella morganii, Citrobacter freundii, and Haemophilus influenzae; >99% of isolates of E. coli, K. pneumoniae, K. oxytoca, P. mirabilis, M. morganii, C. freundii, and H. influenzae were susceptible to ceftaroline-avibactam according to CLSI MIC interpretative criteria for ceftaroline. Ceftaroline was less active than ceftaroline-avibactam against all species of Enterobacteriaceae tested, with rates of susceptibility ranging from 93.9% (P. mirabilis) to 54.0% (S. marcescens). All isolates of methicillin-susceptible Staphylococcus aureus (MIC90, 0.25 ?g/ml) and 99.6% of methicillin-resistant S. aureus isolates (MIC90, 1 ?g/ml) were susceptible to ceftaroline; the addition of avibactam to ceftaroline did not alter its activity against staphylococci or streptococci. All isolates of Streptococcus pneumoniae (MIC90, 0.03 ?g/ml), Streptococcus pyogenes (MIC90, ? 0.03 ?g/ml), and Streptococcus agalactiae (MIC90, 0.015 ?g/ml) tested were susceptible to ceftaroline. We conclude that combining avibactam with ceftaroline expanded its spectrum of activity to include most isolates of Enterobacteriaceae resistant to third-generation cephalosporins, including extended-spectrum ?-lactamase (ESBL)- and AmpC-producing E. coli and ESBL-producing K. pneumoniae, while maintaining potent activity against staphylococci and streptococci. PMID:23979759

Karlowsky, James A; Adam, Heather J; Baxter, Melanie R; Lagacé-Wiens, Philippe R S; Walkty, Andrew J; Hoban, Daryl J; Zhanel, George G

2013-11-01

275

In Vitro Activity of Ceftaroline-Avibactam against Gram-Negative and Gram-Positive Pathogens Isolated from Patients in Canadian Hospitals from 2010 to 2012: Results from the CANWARD Surveillance Study  

PubMed Central

The in vitro activities of ceftaroline-avibactam, ceftaroline, and comparative agents were determined for a collection of bacterial pathogens frequently isolated from patients seeking care at 15 Canadian hospitals from January 2010 to December 2012. In total, 9,758 isolates were tested by using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method (document M07-A9, 2012), with MICs interpreted by using CLSI breakpoints (document M100-S23, 2013). Ceftaroline-avibactam demonstrated potent activity (MIC90, ?0.5 ?g/ml) against Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Morganella morganii, Citrobacter freundii, and Haemophilus influenzae; >99% of isolates of E. coli, K. pneumoniae, K. oxytoca, P. mirabilis, M. morganii, C. freundii, and H. influenzae were susceptible to ceftaroline-avibactam according to CLSI MIC interpretative criteria for ceftaroline. Ceftaroline was less active than ceftaroline-avibactam against all species of Enterobacteriaceae tested, with rates of susceptibility ranging from 93.9% (P. mirabilis) to 54.0% (S. marcescens). All isolates of methicillin-susceptible Staphylococcus aureus (MIC90, 0.25 ?g/ml) and 99.6% of methicillin-resistant S. aureus isolates (MIC90, 1 ?g/ml) were susceptible to ceftaroline; the addition of avibactam to ceftaroline did not alter its activity against staphylococci or streptococci. All isolates of Streptococcus pneumoniae (MIC90, 0.03 ?g/ml), Streptococcus pyogenes (MIC90, ?0.03 ?g/ml), and Streptococcus agalactiae (MIC90, 0.015 ?g/ml) tested were susceptible to ceftaroline. We conclude that combining avibactam with ceftaroline expanded its spectrum of activity to include most isolates of Enterobacteriaceae resistant to third-generation cephalosporins, including extended-spectrum ?-lactamase (ESBL)- and AmpC-producing E. coli and ESBL-producing K. pneumoniae, while maintaining potent activity against staphylococci and streptococci.

Adam, Heather J.; Baxter, Melanie R.; Lagace-Wiens, Philippe R. S.; Walkty, Andrew J.; Hoban, Daryl J.; Zhanel, George G.

2013-01-01

276

Chemical modification of capuramycins to enhance antibacterial activity  

PubMed Central

Objectives To extend capuramycin spectrum of activity beyond mycobacteria and improve intracellular drug activity. Methods Three capuramycin analogues (SQ997, SQ922 and SQ641) were conjugated with different natural and unnatural amino acids or decanoic acid (DEC) through an ester bond at one or more available hydroxyl groups. In vitro activity of the modified compounds was determined against Mycobacterium spp. and representative Gram-positive and Gram-negative bacteria. Intracellular activity was evaluated in J774A.1 mouse macrophages infected with Mycobacterium tuberculosis (H37Rv). Results Acylation of SQ997 and SQ641 with amino undecanoic acid (AUA) improved in vitro activity against most of the bacteria tested. Conjugation of SQ922 with DEC, but not AUA, improved its activity against Gram-positive bacteria. In the presence of efflux pump inhibitor phenylalanine arginine ?-naphthyl amide, MICs of SQ997-AUA, SQ641-AUA and SQ922-DEC compounds improved even further against drug-susceptible and drug-resistant Staphylococcus aureus. In Gram-negative bacteria, EDTA-mediated permeabilization caused 4- to 16-fold enhancement of the activity of AUA-conjugated SQ997, SQ922 and SQ641. Conjugation of all three capuramycin analogues with AUA improved intracellular killing of H37Rv in murine macrophages. Conclusions Conjugation of capuramycin analogues with AUA or DEC enhanced in vitro activity, extended the spectrum of activity in Gram-positive bacteria and increased intracellular activity against H37Rv.

Bogatcheva, Elena; Dubuisson, Tia; Protopopova, Marina; Einck, Leo; Nacy, Carol A.; Reddy, Venkata M.

2011-01-01

277

24-Branched ?5 sterols from Laurencia papillosa red seaweed with antibacterial activity against human pathogenic bacteria.  

PubMed

Methanol extract of thirty-eight seaweeds samples were first screened against Gram-positive (Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6051) and -negative (Escherichia coli ATCC 8739 and Pseudomonas aerugenosa ATCC 9027) bacteria. Laurencia papillosa (Ceramiales, Rhodomelaceae, Rhodophyta) gave maximum antimicrobial activity against these bacteria. It was finally tested against four clinical Gram-negative isolates (E. coli, P. aerugenosa, Klebsiella pneumoniae and Shigella flexineri) and exhibited antibacterial activity. The extract was fractionated by column chromatography and the active fraction was identified as a cholesterol derivative, 24-propylidene cholest-5-en-3?-ol using gas chromatography mass spectrometry (GC-MS). The electrospray ionization mass spectrometry (ESI-MS) and FT-IR spectroscopic analysis also supported the structure of the compound. The minimum inhibitory concentration ranged from 1.2 to 1.7 ?g/mL (IC50) against clinical isolates. This is the first report of antibacterial activity of this cholesterol derivative. This compound could be exploited as potential lead molecule against broad spectrum drug development. The results also affirm the potential of seaweeds as an important natural source of antimicrobial compounds for pharmaceutical industries. PMID:23910454

Kavita, Kumari; Singh, Vijay Kumar; Jha, Bhavanath

2014-04-01

278

Fatty acid composition, antioxidant and antibacterial activities of Adonis wolgensis L. extract  

PubMed Central

Objectives: The objective of this study was to analyze the fatty acid content, antioxidant, and antibacterial activities of hydro-methanolic extract of Adonis wolgensis L. (A. wolgensis L.) growing wild in north of Iran. Materials and Methods: Oils of A. wolgensis L. was obtained by means of Soxhlet apparatus from leaves and stems. Methyl esters were derived from the oily mixtures by trans-esterification process and were analyzed by GC/FID and GC/MS systems. Phenolic compounds extraction was done with aqueous methanol (90%). This extract was investigated for antioxidant activity using DPPH radical scavenging and reducing power methods and was also tested against a panel of microorganisms. Results: Linolenic acid (45.83%) and oleic acid (47.54%) were the most abundant fatty acids in leaves and stems, respectively. Hydro-methanolic extract with the high amount of total phenolics (9.20 ±0.011 mg GAE per dry matter) was the potent antioxidant in the assays. Results obtained from measurements of MIC for extract, indicated that E. coli, S. aureus, and S. enteritidis were the most sensitive microorganisms tested, but no activity was observed against Gram-positive microorganism (B. subtilis). Conclusion: The results obtained from the present study indicated that the oil of A. wolgensis leaves and stems contained a high source of poly-unsaturated fatty acids (PUFAs). These results also showed that hydro-methanolic extract of this plant contained significant antioxidant and antibacterial activities.

Mohadjerani, Maryam; Tavakoli, Rahmatollah; Hosseinzadeh, Rahman

2014-01-01

279

Antibacterial, Antifungal, and Cytotoxic Activities of Distictis buccinatoria  

Microsoft Academic Search

The current study was undertaken to evaluate the in vitro. antimicrobial and cytotoxic activity of six crude extracts obtained from the leaves and flowers of Distictis buccinatoria. (DC.) A.H. Gentry (Bignoniaceae). Antimicrobial activity was tested against the Gram-positive bacteria Staphylococcus aureus., Streptococcus pyogenes., and Streptococcus faecalis.; the Gram-negative bacteria Escherichia coli., Klebsiella pneumoniae., and Salmonella typhi.; and the fungi Candida

María Gabriela Rojas; Víctor Navarro; Daniel Alonso; María Yolanda Ríos; Jaime Tortoriello; Rubén Román-Ramos

2007-01-01

280

8-Azatetracyclines: Synthesis and Evaluation of a Novel Class of Tetracycline Antibacterial Agents  

PubMed Central

A novel series of fully synthetic 8-azatetracyclines was prepared and evaluated for antibacterial activity. Compounds were identified that overcome both efflux (tet(K)) and ribosomal protection (tet(M)) tetracycline resistance mechanisms and are active against Gram-positive and Gram-negative organisms. Two compounds were identified that exhibit comparable efficacy to marketed tetracyclines in in vivo models of bacterial infection.

2011-01-01

281

Purification of a lectin with antibacterial activity from Bothrops leucurus snake venom.  

PubMed

A novel lectin was isolated from Bothrops leucurus snake venom using a combination of affinity and gel filtration chromatographies. The lectin (BlL) agglutinated glutaraldehyde-treated rabbit and human erythrocytes with preference for rabbit erythrocytes. Galactose, raffinose, lactose, fetal bovine serum and casein inhibited lectin-induced rabbit erythrocyte agglutination. BlL, with a molecular mass of 30 kDa and composed of two subunits of 15 kDa, showed dependence on calcium. BlL is an acidic protein with highest activity over the pH range of 4.0-7.0 and stable under heating to 70°C. Fluorescence emission spectra showed tryptophan residues partially buried within the lectin structure. The percentages of secondary structure revealed by circular dichroism were 1% ?-helix, 44% ?-sheet, 24% ?-turn and 31% unordered. BlL showed effective antibacterial activity against Gram-positive bacteria Staphylococcus aureus, Enterococcus faecalis and Bacillus subtilis with minimal inhibitory concentrations of 31.25, 62.25 and 125 ?g/mL, respectively. In conclusion, B. leucurus snake venom contains a galactoside-binding lectin with antibacterial activity. PMID:21334449

Nunes, Erika dos Santos; de Souza, Mary Angela Aranda; Vaz, Antônio Fernando de Melo; Santana, Giselly Maria de Sá; Gomes, Francis Soares; Coelho, Luana Cassandra Breitenbach Barroso; Paiva, Patrícia Maria Guedes; da Silva, Rejane Maria Lira; Silva-Lucca, Rosemeire Aparecida; Oliva, Maria Luiza Vilela; Guarnieri, Miriam Camargo; Correia, Maria Tereza dos Santos

2011-05-01

282

Antibacterial Activity of Lantana camara Linn and Lantana montevidensis Brig Extracts from Cariri-Cear?, Brazil  

PubMed Central

The use of medicinal plants with therapeutics properties represents a secular tradition in different cultures, mainly in underdeveloped countries. Lantana camara Linn and Lantana montevidensis Briq (Verbenaceae) found in tropical and subtropical areas around the world are popularly known as “camará” or “chumbinho.” In popular medicines, both plants are used as antipyretic and carminative and in the treatment of respiratory system infections. In this study, the antibacterial activity of the ethanolic extracts of L. camara and L. montevidensis leaves and roots against gram-positive and gram-negative strains standard and multi-resistant bacteria isolated from clinical material are presented. In order to determine the minimal inhibitory concentration (MIC), the microdilution method was used. The extracts demonstrated antibacterial activity against all tested bacteria, but the L. montevidensis fresh leaves extract present the best result against P. aeruginosa (MIC 8 ?g/mL) and against multi-resistant E. coli (Ec 27) (MIC 16 ?g/mL). These results drive new researches with both species in order to isolate the constituents responsible for the activity.

Barreto, FS; Sousa, EO; Campos, AR; Costa, JGM; Rodrigues, FFG

2010-01-01

283

Antibacterial activities of crude extract of Aloe barbadensis to clinically isolated bacterial pathogens.  

PubMed

The antibacterial activity of Aloe barbadensis was tested on clinically isolated bacterial pathogens i.e. Enterococcus bovis, Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Proteus mirabilis, Pseudomonas aeruginosa, Morganella morganii, and Klebsiella pneumoniae causing infection in human being. Ethanolic and aqueous extracts were used for the antibacterial effect, which was measured by the appearance of zone of inhibition. Relatively higher MIC concentrations were obtained for gram negative bacteria E. coli and K. pneumoniae, with ethanol extract; however, no inhibitory effect was noted for aqueous extract. Ethanolic extract possesses great inhibitory activity for gram positive bacteria, E. bovis followed by S. aureus. Among gram negative bacteria, highest inhibitory effect was observed with P. aeruginosa, followed by M. morganii, P. mirabilis, and P. vulgaris, which was significant (p < 0.01) than E. coli and K. pneumoniae. Antimicrobial activity tests of crude extract of A. barbadensis were carried out to validate the use of traditional medicinal herbal and results of this study tend to give credence to the common use of A. barbadensis gel and leaf. PMID:19263248

Pandey, Ruchi; Mishra, Avinash

2010-03-01

284

Antibacterial Activity of Lantana camara Linn and Lantana montevidensis Brig Extracts from Cariri-Ceará, Brazil.  

PubMed

The use of medicinal plants with therapeutics properties represents a secular tradition in different cultures, mainly in underdeveloped countries. Lantana camara Linn and Lantana montevidensis Briq (Verbenaceae) found in tropical and subtropical areas around the world are popularly known as "camará" or "chumbinho." In popular medicines, both plants are used as antipyretic and carminative and in the treatment of respiratory system infections. In this study, the antibacterial activity of the ethanolic extracts of L. camara and L. montevidensis leaves and roots against gram-positive and gram-negative strains standard and multi-resistant bacteria isolated from clinical material are presented. In order to determine the minimal inhibitory concentration (MIC), the microdilution method was used. The extracts demonstrated antibacterial activity against all tested bacteria, but the L. montevidensis fresh leaves extract present the best result against P. aeruginosa (MIC 8 ?g/mL) and against multi-resistant E. coli (Ec 27) (MIC 16 ?g/mL). These results drive new researches with both species in order to isolate the constituents responsible for the activity. PMID:21331189

Barreto, Fs; Sousa, Eo; Campos, Ar; Costa, Jgm; Rodrigues, Ffg

2010-01-01

285

Synthesis, anti-MRSA, and anti-VRE activity of hemin conjugates with amino acids and branched peptides.  

PubMed

The increasing prevalence of antibiotic-resistant bacterial strains has necessitated the synthesis of novel antibacterial agents. It was previously shown that naturally occurring metalloporphyrin hemin possesses dark antibacterial activity against Gram-positive bacteria. To improve hemin antibacterial activity, we synthesized a number of hemin conjugates with amino acids and branched peptides. Arginine-containing hemin conjugates demonstrated high antibacterial activity against Gram-positive bacteria including methicillin- and vancomycin-resistant strains in vitro. Most of the synthesized conjugates showed low toxicity against human erythrocytes and leukocytes. PMID:23663365

Okorochenkov, Sergei A; Zheltukhina, Galina A; Mirchink, Elena P; Isakova, Elena B; Feofanov, Alexey V; Nebolsin, Vladimir E

2013-10-01

286

Streptococcus mutans: a new Gram-positive paradigm?  

PubMed Central

Despite the enormous contributions of the bacterial paradigms Escherichia coli and Bacillus subtilis to basic and applied research, it is well known that no single organism can be a perfect representative of all other species. However, given that some bacteria are difficult, or virtually impossible, to cultivate in the laboratory, that some are recalcitrant to genetic and molecular manipulation, and that others can be extremely dangerous to manipulate, the use of model organisms will continue to play an important role in the development of basic research. In particular, model organisms are very useful for providing a better understanding of the biology of closely related species. Here, we discuss how the lifestyle, the availability of suitable in vitro and in vivo systems, and a thorough understanding of the genetics, biochemistry and physiology of the dental pathogen Streptococcus mutans have greatly advanced our understanding of important areas in the field of bacteriology such as interspecies biofilms, competence development and stress responses. In this article, we provide an argument that places S. mutans, an organism that evolved in close association with the human host, as a novel Gram-positive model organism.

Quivey, Robert G.; Koo, Hyun; Abranches, Jacqueline

2013-01-01

287

Glycopeptide resistance in gram-positive cocci: a review.  

PubMed

Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens in the past two decades all over the world and have seriously limited the choices available to clinicians for treating infections caused by these agents. Methicillin-resistant Staphylococcus aureus, perhaps the most notorious among the nosocomial pathogens, was till recently susceptible to vancomycin and the other glycopeptides. Emergence of vancomycin nonsusceptible strains of S. aureus has led to a worrisome scenario where the options available for treating serious infections due to these organisms are very limited and not well evaluated. Vancomycin resistance in clinically significant isolates of coagulase-negative staphylococci is also on the rise in many setups. This paper aims to highlight the genetic basis of vancomycin resistance in Enterococcus species and S. aureus. It also focuses on important considerations in detection of vancomycin resistance in these gram-positive bacteria. The problem of glycopeptide resistance in clinical isolates of coagulase-negative staphylococci and the phenomenon of vancomycin tolerance seen in some strains of Streptococcus pneumoniae has also been discussed. Finally, therapeutic options available and being developed against these pathogens have also found a mention. PMID:22778729

Sujatha, S; Praharaj, Ira

2012-01-01

288

Antibacterial and antifungal activities of crude plant extracts from Colombian biodiversity.  

PubMed

On a global scale, people have used plants to treat diseases and infections, and this has raised interest on the plant biodiversity potencial in the search of antimicrobial principles. In this work, 75 crude n-hexanes, dichloromethane and methanol extracts from the aerial parts of 25 plants belonging to four botanical families (Asteraceae, Euphorbiaceae, Rubiaceae and Solanaceae), collected at the Natural Regional Park Ucumari (Risaralda, Colombia), were evaluated for their antibacterial and antifungal activities by the agar well diffusion method. The antibacterial activities were assayed against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, and three Gram-negative ones named, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. In addition, the same plant extracts were tested against the yeast Candida albicans and the fungi Aspergillus fumigatus and Fusarium solani. Overall, the plant extracts examined displayed better bactericide rather than fungicide activities. In general, the best antibacterial activity was showed by the plant extracts from the Rubiaceae family, followed in order by the extracts from the Euphorbiaceae and Solanaceae ones. It is important to emphasize the great activity displayed by the methanol extract of Alchornea coelophylla (Euphorbiaceae) that inhibited four out of five bacteria tested (B. Subtilis, P. aeruginosa, S. aureus and E. coli). Furthermore, the best Minimal Inhibitory Concentration for the extracts with antifungal activities were displayed by the dichloromethane extracts from Acalypha diversifolia and Euphorbia sp (Euphorbiaceae). The most susceptible fungus evaluated was F. Solani since 60% and 20% of the dichloromethane and methanol extracts evaluated inhibited the growth of this phytopathogenic fungus. The antimicrobial activity of the different plant extracts examined in this work could be related to the secondary metabolites contents and their interaction and susceptibility of pathogenic microorganism evaluated. PMID:23342508

Niño, Jaime; Mosquera, Oscar M; Correa, Yaned M

2012-12-01

289

Synthesis and in vitro antibacterial activity of 5-Halogenomethylsulfonyl- benzimidazole and benzotriazole derivatives.  

PubMed

A series of 5-halogenomethylsulfonylbenzimidazole and benzotriazole derivatives was synthesized as potential antibacterial agents. A new method of synthesis of benzimidazoles was developed. The antimicrobial activities of these compounds were tested against a series of reference and clinical strains. The reference strains include Gram-positive bacteria (S. aureus, S. epidermidis, B. subtilis, B. cereus, E. hirae, M. luteus) and Gram-negative rods (E. coli, P. vulgaris, P. aeruginosa, B. bronchiseptica). The clinical strains include six methicillin-resistant (MRSA) and two methicillin-sensitive (MSSA) S. aureus strains, one methicillin-resistant S. epidermidis, three E. faecalis and two E. faecium strains. Compound with trifluoromethyl- substituent at C-2 position (4) displayed significant antibacterial activities comparable with nitrofurantoin against four strains, and higher against Micrococcus luteus. MIC values for clinical Staphylococci strains (MRSA) were 12.5-25 ?g/mL; for Enterococcus strains these values were 50-100 ?g/mL. MIC values for reference and clinical strains of Staphylococcus and Enterococcus group were similar, respectively. PMID:23339322

Ochal, Zbigniew; Bretner, Maria; Wolinowska, Renata; Tyski, Stefan

2013-12-01

290

Fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity  

PubMed Central

Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12–3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO3. The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller–Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.

Shameli, Kamyar; Ahmad, Mansor Bin; Zargar, Mohsen; Yunus, Wan Md Zin Wan; Ibrahim, Nor Azowa

2011-01-01

291

Antioxidant and antibacterial activity of six edible wild plants (Sonchus spp.) in China.  

PubMed

The total phenolic and flavonoid, antioxidant and antibacterial activities of six Sonchus wild vegetables (Sonchus oleraceus L., Sonchus arvensis L., Sonchus asper (L.) Hill., Sonchus uliginosus M.B., Sonchus brachyotus DC. and Sonchus lingianus Shih) in China were investigated. The results revealed that S. arvensis extract and S. oleraceus extract contained the highest amount of phenolic and flavonoid, respectively. Among the methanol extracts of six Sonchus species, S. arvensis extract exhibited the highest radical (DPPH and ABTS+ scavenging power and lipid peroxidation inhibitory power. It also exhibited the highest reducing power at 500?µg?mL?¹ by A (700)?=?0.80. The results of antibacterial test indicated that the S. oleraceus extract showed higher activity than the other five Sonchus wild vegetables extracts, both in Gram-negative bacteria (Escherichia coli, Salmonella enterica and Vibrio parahaemolyticus) and in a Gram-positive bacterium (Staphylococcus aureus). These results indicate that Sonchus wild food plants might be applicable in natural medicine and healthy food. PMID:21793765

Xia, Dao-Zong; Yu, Xin-Fen; Zhu, Zhuo-Ying; Zou, Zhuang-Dan

2011-12-01

292

Antifungal and antibacterial activities of Mexican tarragon (Tagetes lucida).  

PubMed

Mexican tarragon (Tagetes lucida Cv. Asteraceae: Campanulatae) is an important, nutritious plant and an effective herbal medicine. Seven coumarins, 7,8-dihydroxycoumarin (4), umbelliferone (7-hydroxycoumarin) (5), scoparone (6,7-dimethoxycoumarin) (7), esculetin (6,7-dihydroxycoumarin) (11), 6-hydroxy-7-methoxycoumarin (12), herniarin (7-methoxycoumarin) (13), and scopoletin (6-methoxy-7-hydroxycoumarin) (14), and three flavonoids, patuletin (18), quercetin (19), and quercetagetin (20), were isolated from CH2Cl2 and MeOH extracts from aerial parts of T. lucida. In addition, 6,7-diacetoxy coumarin (15), 6-methoxy-7-acetylcoumarin (16), and 6-acetoxy-7-methoxycoumarin (17) derivatives were synthesized. 8-Methoxypsoralen (1), 8-acetyl-7-hydroxycoumarin (2), 7,8-dihydroxy-6-meth-oxycoumarin (3), 6,7-dimethoxy-4-methylcoumarin (6), 5,7-dihydroxy-4-methylcoumarin (8), 4-hydroxycoumarin (9), 4-hydroxy-6,7-dimethylcoumarin (10), naringenin (21), glycoside-7-rhamnonaringin (22), and rutin (23) were commercially obtained (Sigma-Aldrich). All of these compounds and extracts (M1 and M2) were assayed against bacteria and fungi. The antibacterial activity was determined on Bacillus subtilis, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Salmonella typhi, Salmonella sp., Shigella boydii, Shigella sp., Enterobacter aerogenes, Enterobacter agglomerans, Sarcina lutea, Staphylococcus epidermidis, Staphylococcus aureus, Yersinia enterolitica, Vibrio cholerae (three El Tor strains, CDC-V12, clinic case, and INDRE-206, were obtained from contaminated water), and V. cholerae (NO-O1). The evaluated fungi were Aspergillus niger, Penicillium notatum, Fusarium moniliforme, Fusarium sporotrichum, Rhizoctonia solani, and Trichophyton mentagrophytes. The most active compounds against Gram-positive and -negative bacteria were the dihydroxylated coumarins 3 and 4. In addition, 2-4, 6, 7, and 11 showed an interesting activity against V. cholerae, a key bacterium in the contaminated water; 2-4 were the most active. Coumarins were the most effective compounds against Gram-negative bacteria. The extract MeOH/CH2Cl2 (1: 4) M2 at 0.4 microg/disk inhibited the growth of E. coli and P. mirabilis (40%), K. pneumoniae (31.1%), Salmonella sp. (35.5%), and Shigella sp. (0%) at 72 h of culture. The dimethoxy compounds 6 and 7 showed a strong activity against fungal strains, especially T. mentagrophytes and R. solani (100% of inhibition at 125.0 and 250.0 microg/mL, respectively). PMID:19127719

Céspedes, Carlos L; Avila, J Guillermo; Martínez, Andrés; Serrato, Blanca; Calderón-Mugica, José C; Salgado-Garciglia, Rafael

2006-05-17

293

Synthesis and antibacterial activity of 4-benzoyl-1-(4-carboxy-phenyl)-5-phenyl-1 H -pyrazole-3-carboxylic acid and derivatives  

Microsoft Academic Search

A new 1H-pyrazole-3-carboxylic acid 2, along with hydrazono-pyridazinone 3, a by-product, and its derivatives 4–7 were synthesized and the structures confirmed by infrared (IR) and 1H and 13C nuclear magnetic resonance (NMR) data. These new compounds were evaluated for their antibacterial activities against Gram-positive\\u000a and Gram-negative bacteria using the tube dilution method. The minimal inhibitory concentrations (MICs) experiments revealed\\u000a that

?shak Bildirici; Ahmet ?ener; Ekrem Atalan; Abdulhamit Battal; Hasan Genç

2009-01-01

294

Structure-based classification of antibacterial activity.  

PubMed

The aim of this study was to develop a simple quantitative structure-activity relationship (QSAR) for the classification and prediction of antibacterial activity, so as to enable in silico screening. To this end a database of 661 compounds, classified according to whether they had antibacterial activity, and for which a total of 167 physicochemical and structural descriptors were calculated, was analyzed. To identify descriptors that allowed separation of the two classes (i.e. those compounds with and without antibacterial activity), analysis of variance was utilized and models were developed using linear discriminant and binary logistic regression analyses. Model predictivity was assessed and validated by the random removal of 30% of the compounds to form a test set, for which predictions were made from the model. The results of the analyses indicated that six descriptors, accounting for hydrophobicity and inter- and intramolecular hydrogen bonding, provided excellent separation of the data. Logistic regression analysis was shown to model the data slightly more accurately than discriminant analysis. PMID:12132888

Cronin, Mark T D; Aptula, Aynur O; Dearden, John C; Duffy, Judith C; Netzeva, Tatiana I; Patel, Hiren; Rowe, Philip H; Schultz, T Wayne; Worth, Andrew P; Voutzoulidis, Konstantinos; Schüürmann, Gerrit

2002-01-01

295

Antibacterial activity of Ocimum sanctum L. fixed oil.  

PubMed

Ocimum sanctum fixed oil showed good antibacterial activity against Staphylococcus aureus, Bacillus pumilus and Pseudomonas aeruginosa, where S. aureus was the most sensitive organism. Sesame and soyabean oils also showed moderate activity against S. aureus. Higher content of linolenic acid in O. sanctum fixed oil could contribute towards its antibacterial activity. The antibacterial activity combined with anti-inflammatory and analgesic activities of the oil, could make it useful in inflammatory disorder resulting from staphylococcal infection. PMID:16187537

Singh, Surender; Malhotra, Manjusha; Majumdar, D K

2005-09-01

296

Chemical Composition and Antibacterial and Cytotoxic Activities of Allium hirtifolium Boiss  

PubMed Central

Allium hirtifolium Boiss. known as Persian shallot, is a spice used as a traditional medicine in Iran and, Mediterranean region. In this study, the chemical composition of the hydromethanolic extract of this plant was analyzed using GC/MS. The result showed that 9-hexadecenoic acid, 11,14-eicosadienoic acid, and n-hexadecanoic acid are the main constituents. The antibacterial activity of the shallot extract was also examined by disk diffusion and microdilution broth assays. It was demonstrated that Persian shallot hydromethanolic extract was effective against 10 different species of pathogenic bacteria including methicillin resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Escherichia coli, Escherichia coli O157:H7, Salmonella typhimurium, Proteus mirabilis, and Klebsiella pneumoniae. Specifically, the minimum concentration of the extract which inhibited bacterial growth (MIC values) was 1.88?mg/mL for most of the gram-positive bacteria. This concentration was not much different from the concentration that was safe for mammalian cells (1.50?mg/mL) suggesting that the hydromethanolic extract of Persian shallot may be a safe and strong antibacterial agent.

Ismail, Salmiah; Jalilian, Farid Azizi; Talebpour, Amir Hossein; Zargar, Mohsen; Shameli, Kamyar; Sekawi, Zamberi; Jahanshiri, Fatemeh

2013-01-01

297

Silver carboxylate metal-organic frameworks with highly antibacterial activity and biocompatibility.  

PubMed

Two novel Ag-based metal-organic frameworks (MOFs) [Ag2(O-IPA)(H2O)·(H3O)] (1) and [Ag5(PYDC)2(OH)] (2) were synthesized under the hydrothermal conditions using aromatic-carboxylic acids containing hydroxyl and pyridyl groups as ligands (HO-H2IPA=5-hydroxyisophthalic acid and H2PYDC=pyridine-3, 5-dicarboxylic acid). Single crystal X-ray diffraction indicated that two compounds exhibit three-dimensional frameworks constructed from different rod-shaped molecular building blocks. Both compounds favor slow release of Ag(+) ions leading to excellent and long-term antimicrobial activities towards Gram-negative bacteria, Escherichia coli (E. coli) and Gram-positive bacteria, Staphylococcus aureus (S. aureus). Their antibacterial potency was evaluated by using a minimal inhibition concentration (MIC) benchmark and an inhibition zone testing. High-resolution transmission electron microscope images indicate that the Ag-based MOFs could rupture the bacterial membrane resulting in cell death. Hematological study showed that these MOFs exhibit good biocompatibility in mice. In addition, good thermal stability and optical stability under UV-visible and visible light are beneficial for their antibacterial application. PMID:24935093

Lu, Xinyi; Ye, Junwei; Zhang, Dekui; Xie, Ruixia; Bogale, Raji Feyisa; Sun, Yuan; Zhao, Limei; Zhao, Qi; Ning, Guiling

2014-09-01

298

Green synthesis of silk sericin-capped silver nanoparticles and their potent anti-bacterial activity  

PubMed Central

In this study, a ‘green chemistry’ approach was introduced to synthesize silk sericin (SS)-capped silver nanoparticles (AgNPs) under an alkaline condition (pH 11) using SS as a reducing and stabilizing agent instead of toxic chemicals. The SS-capped AgNPs were successfully synthesized at various concentrations of SS and AgNO3, but the yields were different. A higher yield of SS-capped AgNPs was obtained when the concentrations of SS and AgNO3 were increased. The SS-capped AgNPs showed a round shape and uniform size with diameter at around 48 to 117 nm. The Fourier transform infrared (FT-IR) spectroscopy result proved that the carboxylate groups obtained from alkaline degradation of SS would be a reducing agent for the generation of AgNPs while COO? and NH2?+ groups stabilized the AgNPs and prevented their precipitation or aggregation. Furthermore, the SS-capped AgNPs showed potent anti-bacterial activity against various gram-positive bacteria (minimal inhibitory concentration (MIC) 0.008 mM) and gram-negative bacteria (MIC ranging from 0.001 to 0.004 mM). Therefore, the SS-capped AgNPs would be a safe candidate for anti-bacterial applications.

2014-01-01

299

Synthesis and characterization of dextran-capped silver nanoparticles with enhanced antibacterial activity.  

PubMed

Dextran-capped silver nanoparticles were synthesized by reducing silver nitrate with NaBH4 in the presence of dextran as capping agent. The characters of silver nanoparticles were investigated using UV-Vis spectrophotometer, nano-grainsize analyzer, X-ray diffraction, and transmission electron microscopy. Results showed that the silver nanoparticles capped with dextran were in uniform shape and narrow size distribution. Moreover, compared with polyvinylpyrrolidone (PVP)-capped silver nanoparticles, the dextran-capped ones possessed better stability. Antibacterial tests of these silver nanoparticles were carried out for Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Results suggested that the dextran-capped silver nanoparticles had high antibacterial activity against both Gram-positive and Gram-negative bacteria. In addition, the cytotoxicity in vitro of the dextran-capped silver nanoparticles was investigated using mouse fibrosarcoma cells (L929). The toxicity was evaluated by the changes of cell morphology and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Results indicated that these silver nanoparticles had slight effect on the survival and proliferation of L-929 cells at their minimal inhibitory concentration (MIC). After modified by dextran, the physiochemical properties of the silver nanoparticles had been improved. We anticipated that these dextran-capped silver nanoparticles could be integrated into systems for biological and pharmaceutical applications. PMID:22852305

Yang, Guili; Lin, Qiuxia; Wang, Chunren; Li, Junjie; Wang, Jian; Zhou, Jin; Wang, Yan; Wang, Changyong

2012-05-01

300

One-step synthesis of silver nanoparticles in an aqueous solution and their antibacterial activities  

NASA Astrophysics Data System (ADS)

A one-step simple synthesis of silver colloid nanoparticles with controllable sizes is presented in this research. In the synthesis, an amino-terminated hyperbranched polymer (HBP-NH2) was applied as a stabilizer and a reductant. The syntheses, performed at various initial AgNO3 concentrations (0.28-0.56 g/l) in a 2 g/l HBP-NH2 aqueous solution, produced silver colloid nanoparticles having average sizes from 3 to 30 nm with narrow size distributions. The formation of silver colloid nanoparticles was characterized by Fourier Transform Infrared Spectrophotometry (FTIR), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), UV/Visible Absorption Spectrophotometry, and X-ray Diffraction (XRD) measurements. The results indicated that both particle size and the UV absorption are strongly dependent on the initial AgNO3 concentrations. The silver colloid nanoparticles, prepared with a 0.35 g/l AgNO3 aqueous solution in the presences of 2 g/l HBP-NH2, showed good antibacterial activities against Gram-negative bacteria ( Escherichia coli) and Gram-positive bacteria ( Staphylococcus aureus). A very low concentration of nano-silver (as low as 3.0 ug/ml Ag) also gave excellent antibacterial performance.

Zhang, Guangyu; Zhang, Feng; Morikawa, Hideaki; Chen, Yueyue

2014-03-01

301

Antiviral and antibacterial polyurethanes of various modalities.  

PubMed

We have prepared and characterized a new polyurethane-based antimicrobial material, N,N-dodecyl,methyl-polyurethane (Quat-12-PU). It exhibits strong antiviral and antibacterial activities when coated (as an organic solution or an aqueous nanosuspension) onto surfaces and antibacterial activity when electrospun into nanofibers. Quat-12-PU surfaces are able to kill airborne Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria, as well as inactivate the enveloped influenza virus (but not the non-enveloped poliovirus). PMID:23306899

Park, Daewon; Larson, Alyssa M; Klibanov, Alexander M; Wang, Yadong

2013-02-01

302

Glucosamine sulfate--environmental antibacterial activity.  

PubMed

We have recently showed antibacterial activity against E. coli in vitro of a trademark Mega-Gluflex-containing glucosamine sulfate (GS) and chondroitin sulfate (CS). The purpose of this study was to examine the antibacterial activity of GS as a new trademark Arthryl (Manufacturer Rottapharm Ltd, Ireland; Distributor in Israel Rafa Laboratories Ltd) in vitro. We used cabbage and chicken broths and milk (every media of 20 ml) left opened for 1 week with and without Arthryl supplements 1,500 mg, the content of one package of the medication. A similar volume (20 ml) is ingested in taking the medication. Experiments with three repeatable results were taken for consideration. Arthryl inhibited environmental bacterial colonies' growth in every media but fungi growth was not impaired. Milk stayed liquid for the whole week with supplement of the Arthryl compared with sour milk transformation without Arthryl. Sample B showed inhibitory properties of the bacterial colonies on the fungi growth. The sample with Arthryl showed progressive growth of fungi without bacterial growth after 10 days of follow up compared with bacterial growth on media without Arthryl. Glucosamine sulfate as a new trademark Arthryl has environmental antibacterial properties but does not inhibit growth of fungal colonies. PMID:19495827

Rozin, Alexander P

2009-10-01

303

Lipoteichoic acid preparations of gram-positive bacteria induce interleukin-12 through a CD14-dependent pathway.  

PubMed Central

Interleukin 12 (IL-12) strongly augments gamma interferon production by natural killer (NK) and T cells. IL-12 also promotes effective cell-mediated immune responses, which are particularly important against intracellular bacteria such as Listeria monocytogenes. While the lipopolysaccharide (LPS) of gram-negative bacteria induces monocyte production of IL-12, the relevant gram-positive components which induce IL-12 production are uncharacterized. We used the human monocytic cell line THP-1 to study IL-12 induction by gram-positive bacteria. Muramyl dipeptides as well as the major muramyl tetrapeptide component of Streptococcus pneumoniae were inactive for inducing IL-12. In contrast, lipoteichoic acid (LTA), a predominant surface glycolipid of gram-positive bacteria, potently induced IL-12 p40 gene expression. A competitive LPS antagonist, Rhodobacter sphaeroides LPS, inhibited LTA-induced IL-12 production, suggesting a common pathway for LPS and LTA in IL-12 activation. Pretreatment of cells with anti-CD14 monoclonal antibody blocked both LPS and LTA induction of IL-12 p40 expression. LTA also induced Thl development in naive CD4 T cells by an IL-12-dependent mechanism, indicating direct induction of physiologic levels of IL-12. Together, these results show that LTA is a potent surface structure of gram-positive bacteria which induces IL-12 in monocytes through a CD14-mediated pathway.

Cleveland, M G; Gorham, J D; Murphy, T L; Tuomanen, E; Murphy, K M

1996-01-01

304

In Vitro Antibacterial Activity of Galls of Quercus infectoria Olivier against Oral Pathogens  

PubMed Central

The galls of Quercus infectoria are commonly used in Malay traditional medicine to treat wound infections after childbirth. In India, they are employed traditionally as dental applications such as that in treatment of toothache and gingivitis. The aim of the present study was to evaluate the antibacterial activity of galls of Quercus infectoria Olivier against oral bacteria which are known to cause dental caries and periodontitis. Methanol and acetone extracts were screened against two Gram-positive bacteria (Streptococcus mutans ATCC 25175 and Streptococcus salivarius ATCC 13419) and two Gram-negative bacteria (Porphyromonas gingivalis ATCC 33277 and Fusobacterium nucleatum ATCC 25586). The screening test of antibacterial activity was performed using agar-well diffusion method. Subsequently, minimum inhibitory concentration (MIC) was determined by using twofold serial microdilution method at a concentration ranging between 0.01?mg/mL and 5?mg/mL. Minimum bactericidal concentration (MBC) was obtained by subculturing microtiter wells which showed no changes in colour of the indicator after incubation. Both extracts showed inhibition zones which did not differ significantly (P < 0.05) against each tested bacteria. Among all tested bacteria, S. salivarius was the most susceptible. The MIC ranges for methanol and acetone extracts were the same, between 0.16 and 0.63?mg/mL. The MBC value, for methanol and acetone extracts, was in the ranges 0.31–1.25?mg/mL and 0.31–2.50?mg/mL, respectively. Both extracts of Q. infectoria galls exhibited similar antibacterial activity against oral pathogens. Thus, the galls may be considered as effective phytotherapeutic agents for the prevention of oral pathogens.

Basri, Dayang Fredalina; Tan, Liy Si; Shafiei, Zaleha; Zin, Noraziah Mohamad

2012-01-01

305

Sarconesiopsis magellanica (Diptera: Calliphoridae) excretions and secretions have potent antibacterial activity.  

PubMed

The most important mechanism for combating infection using larval therapy depends on larval excretions and secretions (ES). The present work was aimed at evaluating Sarconesiopsis magellanica (Diptera: Calliphoridae) ES antibacterial activity in six bacterial strains (three Gram-positive and three Gram-negative) and comparing this to the effect of Lucilia sericata-derived ES. Antibacterial activity at 50?g/mL minimum inhibitory concentration (MIC) was observed for Staphylococcus epidermidis ATCC-12228 and Staphylococcus aureus ATCC-29213 strains, when the turbidimetry test involving S. magellanica ES was used; the rest of the bacterial strains (Staphylococcus aureus ATCC-6538, Pseudomonas aeruginosa ATCC-10145, Pseudomonas aeruginosa ATCC-9027 and Pseudomonas aeruginosa ATCC-27853) were inhibited at a 100?g/mL MIC. Twice the amount was required to inhibit the aforementioned bacteria with L. sericata-derived ES using this same technique; a similar trend was observed when the agar diffusion method was used instead. Furthermore, when the previously established MIC for each bacterial strain was used, their colonies became reduced following 1-6h incubation with S. magellanica derived ES, whilst the reduction occurred from 2 to 6hours with those from L. sericata. Although the MIC for each strain obtained with ciprofloxacin was lower than those established when using either blowfly derived-ES, the gradual reduction of the colonies occurred at a longer incubation time (6h or more). The results showed that S. magellanica ES antibacterial activity was more potent and effective, compared to that of L. sericata-derived ES. PMID:24754920

Díaz-Roa, Andrea; Gaona, María A; Segura, Nydia A; Suárez, Diana; Patarroyo, Manuel A; Bello, Felio J

2014-08-01

306

Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product  

PubMed Central

In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria. Streptococcus thermophilus T2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, by S. thermophilus T2 cells, was measured by the end of the late-log phase (90 AU ml?1) with a bacteriocine production rate of 9.3 (AU ml?1) h?1. In addition, our findings showed that the bacteriocin, produced by S. thermophilus T2, was stable over a wide pH range (4–8); this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food.

Mezaini, Abdelkader; Chihib, Nour-Eddine; Dilmi Bouras, Abdelkader; Nedjar-Arroume, Naima; Hornez, Jean Pierre

2009-01-01

307

Antibacterial Activity of Murrayaquinone A and 6-Methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione  

PubMed Central

The antibacterial activity of Murrayaquinone A (10), a naturally occurring carbazoloquinone alkaloid, and 6-methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione (11), a synthetic carbazoloquinone, both obtained during the development of the synthesis of Carbazomycin G, having unique quinone moiety, was studied against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas sp.) bacteria. Compound 10 showed antibacterial activities against both of Escherichia coli and Staphylococcus aureus whereas compound 11 indicated the activity against Staphylococcus aureus only. Both compounds 10 and 11 exhibited minimum inhibitory concentration (MIC) of 50??g?mL?1 against Staphylococcus aureus.

Chakraborty, Biswanath; Chakraborty, Suchandra; Saha, Chandan

2014-01-01

308

Chemical composition and in vitro antioxidant and antibacterial activity of Heracleum transcaucasicum and Heracleum anisactis roots essential oil.  

PubMed

Introduction: In vitro antioxidant and antibacterial activity and volatile compositions of two Heracleum species (Apiaceae) including Heracleum transcaucasicum and Heracleum anisactis roots Essential Oil (EO) were investigated. Methods: The volatile compositions of EOs were analyzed by GC/Mass spectroscopy. To detect the antioxidant activity of essential oils TLC-bioautography and DPPH radical scavenging assay by spectrophotometry was performed. Additionally, the antibacterial activity of two essential oils were studied and compared against four pathogenic bacteria by agar disc diffusion method and MIC values of the EOs were determined using the broth dilution method. Results: Myristicin was the dominant component in both EOs. It was identified as 96.87% and 95.15% of the essential oil composition of H. transcaucasicum and H. anisactis roots, respectively. The TLC-bioautography showed antioxidant spots in both EOs and IC50 of H. anisactis and H. transcaucasicum EO was found to be 54 ?g × ml (-1) and 77 ?g × ml (-1), respectively. Regarding the antimicrobial assay, H. anisactis EO exhibited weak to moderate antibacterial activity against gram-positive bacteria and also Escherichia coli, whereas the essential oil from H. transcaucasicum was inactive. Conclusion: Based on the results from this study, both tested EOs mainly consist of myristicin. Despite the presence of myristicin with known antibacterial property, the EO from H. transcacausicum showed no antibacterial activity. Thus it is supposed that the biological activity of plants is remarkably linked to the extracts' chemical profile and intercomponents' synergistic or antagonistic effect could play a crucial role in bioactivity of EOs and other plant extracts. PMID:25035849

Torbati, Mohammadali; Nazemiyeh, Hossein; Lotfipour, Farzaneh; Nemati, Mahboob; Asnaashari, Solmaz; Fathiazad, Fatemeh

2014-01-01

309

Chemical composition and in vitro antioxidant and antibacterial activity of Heracleum transcaucasicum and Heracleum anisactis roots essential oil  

PubMed Central

Introduction: In vitro antioxidant and antibacterial activity and volatile compositions of two Heracleum species (Apiaceae) including Heracleum transcaucasicum and Heracleum anisactis roots Essential Oil (EO) were investigated. Methods: The volatile compositions of EOs were analyzed by GC/Mass spectroscopy. To detect the antioxidant activity of essential oils TLC-bioautography and DPPH radical scavenging assay by spectrophotometry was performed. Additionally, the antibacterial activity of two essential oils were studied and compared against four pathogenic bacteria by agar disc diffusion method and MIC values of the EOs were determined using the broth dilution method. Results: Myristicin was the dominant component in both EOs. It was identified as 96.87% and 95.15% of the essential oil composition of H. transcaucasicum and H. anisactis roots, respectively. The TLC-bioautography showed antioxidant spots in both EOs and IC50 of H. anisactis and H. transcaucasicum EO was found to be 54 ?g × ml (-1) and 77 ?g × ml (-1), respectively. Regarding the antimicrobial assay, H. anisactis EO exhibited weak to moderate antibacterial activity against gram-positive bacteria and also Escherichia coli, whereas the essential oil from H. transcaucasicum was inactive. Conclusion: Based on the results from this study, both tested EOs mainly consist of myristicin. Despite the presence of myristicin with known antibacterial property, the EO from H. transcacausicum showed no antibacterial activity. Thus it is supposed that the biological activity of plants is remarkably linked to the extracts’ chemical profile and intercomponents’ synergistic or antagonistic effect could play a crucial role in bioactivity of EOs and other plant extracts.

Torbati, Mohammadali; Nazemiyeh, Hossein; Lotfipour, Farzaneh; Nemati, Mahboob; Asnaashari, Solmaz; Fathiazad, Fatemeh

2014-01-01

310

Antibacterial and antifungal activities of polyketide metabolite from marine Streptomyces sp. AP-123 and its cytotoxic effect.  

PubMed

A Gram positive, filamentous, spore forming antagonistic Streptomyces sp. AP-123 derived from marine region of Andra Pradesh, India, was studied for its medical importance. Among the 210 Streptomyces strains screened at 64.3% exhibited activity against Gram positive bacteria, 48.5% showed activity towards Gram negative bacteria, 38.8% exhibited both Gram positive and negative bacteria and 80.85% strains revealed significant antifungal activity. However, primary screening revealed that Streptomyces sp. AP-123 exhibited significant antimicrobial activity against all the tested bacteria compared to other Streptomyces strains. The presence of l-diaminopimelic acid and glycine in the cell wall hydrolysates and streptomycin resistance indicated the strain belonged to Streptomyces genus. The 16S rDNA gene based phylogenetic affiliation was determined by using bioinformatic tools and it was identified as Streptomyces sp. AP-123 with 99% sequence similarity to Streptomyces flavogriseus. The antimicrobial substances were extracted by hexane and ethyl acetate from spent medium in which Streptomyces sp. AP-123 was cultivated at 30 °C for 5 d. The antimicrobial activity was assessed using broth micro-dilution technique. A compound was obtained by eluting the crude extract using varying concentrations of solvents followed by the chromatographic purification. Based on the IR, (13)C NMR and (1)H NMR spectral data, the compound was identified as polyketide related antibiotic. It exhibited significant antibacterial activity against Gram positive and Gram negative bacteria and also showed a potent cytotoxic activity against cell lines viz. Vero (Green monkey kidney) and HEP2 (laryngeal carcinoma cells) in vitro. The lowest Minimum Inhibitory Concentration (MIC) of the compound against Bacillus subtilis and Staphylococcus aureus were 25 and 37.5 ?g mL(-1), respectively. Against Escherichia coli and Pseudomonas aeruginosa it exhibited MIC of 50 and 37.58 ?g mL(-1), respectively. However, against Candida albicans and filamentous fungus, Aspergillus niger the MIC values were 12.5 and 25 ?g mL(-1), respectively. Cloning and sequence analysis of ketoacyl synthase (KS) gene revealed similarity to the type II polyketide synthase (PKS) gene of Streptomyces species. PMID:22963878

Arasu, Mariadhas Valan; Duraipandiyan, Veeramuthu; Ignacimuthu, Savarimuthu

2013-01-01

311

Structural and Functional Diversity of Microcins, Gene-Encoded Antibacterial Peptides from Enterobacteria  

Microsoft Academic Search

Microcins are a peculiar class of gene-encoded low-molecular-mass antibacterial peptides secreted by enterobacteria. They contribute to the regulation of microbial competitions within the intestinal microbiota. The genetic systems involved in microcin biosynthesis share a conserved organization. Similar to bacteriocins of Gram-positive bacteria, microcins exert potent antibacterial activity directed against phylogenetically-related bacterial strains, with minimal inhibitory concentrations in the nanomolar range.

Sophie Duquesne; Vanessa Petit; Jean Peduzzi; Sylvie Rebuffat

2007-01-01

312

Essential oils: their antibacterial properties and potential applications in foods—a review  

Microsoft Academic Search

In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 ?l ml?1. Gram-negative organisms are slightly less susceptible than gram-positive bacteria. A number of EO components has been identified as effective antibacterials, e.g. carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde

Sara Burt

2004-01-01

313

Anaerobic naphthalene degradation by Gram-positive, iron-reducing bacteria.  

PubMed

An anaerobic naphthalene-degrading culture (N49) was enriched with ferric iron as electron acceptor. A closed electron balance indicated the total oxidation of naphthalene to CO(2). In all growing cultures, the concentration of the presumed central metabolite of naphthalene degradation, 2-naphthoic acid, increased concomitantly with growth. The first metabolite of anaerobic methylnaphthalene degradation, naphthyl-2-methyl-succinic acid, was not identified in culture supernatants, which does not support a methylation to methylnaphthalene as the initial activation reaction of naphthalene, but rather a carboxylation, as proposed for other naphthalene-degrading cultures. Substrate utilization tests revealed that the culture was able to grow on 1-methyl-naphthalene, 2-methyl-naphthalene, 1-naphthoic acid or 2-naphthoic acid, whereas it did not grow on 1-naphthol, 2-naphthol, anthracene, phenanthrene, indane and indene. Terminal restriction fragment length polymorphism and 16S rRNA gene sequence analyses revealed that the microbial community of the culture was dominated by one bacterial microorganism, which was closely related (99% 16S sequence similarity) to the major organism in the iron-reducing, benzene-degrading enrichment culture BF [ISME J (2007) 1: 643; Int J Syst Evol Microbiol (2010) 60: 686]. The phylogenetic classification supports a new candidate species and genus of Gram-positive spore-forming iron-reducers that can degrade non-substituted aromatic hydrocarbons. It furthermore indicates that Gram-positive microorganisms might also play an important role in anaerobic polycyclic aromatic hydrocarbon-degradation. PMID:22066721

Kleemann, Rita; Meckenstock, Rainer U

2011-12-01

314

Isolation, characterisation and antibacterial activity of new compounds from methanolic extract of seeds of Caesalpinia crista L. (Caesalpinaceae).  

PubMed

Phytochemical study on the methanolic extract of Caesalpinia crista afforded two novel compounds, 2-hydroxytrideca-3,6-dienyl-pentanoate and octacosa-12,15-diene along with known compounds 3-O-methylellagic acid 3'O-?-rhamnopyranoside, ?-sitosterol and sucrose. Compound 3-O-methylellagic acid 3'O-?-rhamnopyranoside is reported for the first time from the plant. Molecular structures, of isolated compounds, were elucidated by using the NMR spectroscopy in combination with IR and mass spectral data. All isolated compounds, extract and fractions were evaluated for in vitro antibacterial activity against various Gram-positive and Gram-negative bacterial strains and found to be significantly active against Staphylococcus aureus and methicillin-resistant S. aureus (minimum inhibitory concentration: 64-512 ?g mL(- 1)). PMID:23822804

Kumar, Ankit; Garg, Vikas; Chaudhary, Anurag; Jain, Pankaj Kumar; Tomar, Praveen Kumar

2014-01-01

315

Antibacterial and Antifungal Activities of Stereum ostrea, an Inedible Wild Mushroom  

PubMed Central

Antibacterial and antifungal activities of liquid culture filtrate, water and ethanol extract (solid culture) of Stereum ostrea were evaluated against 5 bacteria and 3 plant pathogenic fungi. To determine the minimal inhibitory concentration (MIC), we studied 5~300 mg/ml concentrations against bacteria and fungi separately. The MIC was 10 mg/ml for Bacillus subtilis and 40 mg/ml for Colletotrichum gloeosporioides and Colletotrichum miyabeanus. Liquid culture filtrate was more effective against Gram positive than Gram negative bacteria, and Staphylococcus aureus was the most inhibited (20.3 mm) bacterium. Water and ethanol extracts were effective against both Gram positive and Gram negative bacteria, and water extract was better than ethanol extract. In water and ethanol extract, inhibition zones were 23.6 and 21.0 mm (S. aureus) and 26.3 and 22.3 mm (Pseudomonas aeruginosa), respectively. For plant pathogenic fungi, the highest and lowest percent inhibition of mycelial growth (PIMG) was found 82.8 and 14.4 against C. miyabeanus and Botrytis cinerea in liquid culture filtrate, respectively. In water extract, the PIMG was found to be the highest 85.2 and lowest 41.7 for C. miyabeanus and C. gloeosporioides, respectively. The inhibitory effect of ethanol extract was better against C. miyabeanus than C. gloeosporioides and B. cinerea. Among 3 samples, water extract was the best against tested pathogenic fungi. This study offers that the extracts isolated from S. ostrea contain potential compounds which inhibit the growth of both bacteria and fungi.

Imtiaj, Ahmed; Jayasinghe, Chandana; Lee, Geon Woo

2007-01-01

316

Green synthesis of silver nanoparticles, their characterization, application and antibacterial activity.  

PubMed

Our research focused on the production, characterization and application of silver nanoparticles (AgNPs), which can be utilized in biomedical research and environmental cleaning applications. We used an environmentally friendly extracellular biosynthetic technique for the production of the AgNPs. The reducing agents used to produce the nanoparticles were from aqueous extracts made from the leaves of various plants. Synthesis of colloidal AgNPs was monitored by UV-Visible spectroscopy. The UV-Visible spectrum showed a peak between 417 and 425 nm corresponding to the Plasmon absorbance of the AgNPs. The characterization of the AgNPs such as their size and shape was performed by Atom Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) techniques which indicated a size range of 3 to 15 nm. The anti-bacterial activity of AgNPs was investigated at concentrations between 2 and 15 ppm for Gram-negative and Gram-positive bacteria. Staphylococcus aureus and Kocuria rhizophila, Bacillus thuringiensis (Gram-positive organisms); Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium (Gram-negative organisms) were exposed to AgNPs using Bioscreen C. The results indicated that AgNPs at a concentration of 2 and 4 ppm, inhibited bacterial growth. Preliminary evaluation of cytotoxicity of biosynthesized silver nanoparticles was accomplished using the InQ™ Cell Research System instrument with HEK 293 cells. This investigation demonstrated that silver nanoparticles with a concentration of 2 ppm and 4 ppm were not toxic for human healthy cells, but inhibit bacterial growth. PMID:24157517

Okafor, Florence; Janen, Afef; Kukhtareva, Tatiana; Edwards, Vernessa; Curley, Michael

2013-10-01

317

Chemical composition, antioxidant and antibacterial activities of the leaf essential oil of Juglans regia L. and its constituents.  

PubMed

The essential oil from the leaves of Juglans regia L. (Juglandaceae) growing wild in Kashmir (India) was obtained by hydrodistillation and analysed by a combination of capillary GC-FID and GC-MS. A total of 38 compounds, representing 92.7% of the oil, were identified and the major components were found to be ?-pinene (15.1%), ?-pinene (30.5%), ?-caryophyllene (15.5%) germacrene D (14.4%) and limonene (3.6%). The essential oil and the main individual constituents were screened for antibacterial activity and the essential oil evaluated for antioxidant activity. Antibacterial activity was evaluated using the disc diffusion and microdilution methods against a group of clinically significant Gram-positive (Staphylococcus epidermidis MTCC-435, Bacillus subtilis MTCC-441, Staphylococcus aureus) and Gram-negative bacteria (Proteus vulgaris MTCC-321, Pseudomonas aeruginosa MTCC-1688, Salmonella typhi, Shigella dyssenteriae, Klebsiella pneumonia and Escherichia coli). The essential oil and its major components exhibited broad spectrum inhibition against all the bacterial strains with Gram-positive being more susceptible to the oil than Gram-negative bacteria. Antioxidant activity of the oil was evaluated by the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydroxyl radicals. In general, the essential oil exhibited high antioxidant activity which was comparable to the reference standards at the same dose (ascorbic acid and butylated hydroxyl toluene, BHT) with IC(50) values of 34.5 and 56.4?g/ml calculated by DPPH and hydroxyl radical scavenging assays respectively. PMID:22951389

Rather, Manzoor A; Dar, Bilal A; Dar, Mohd Yousuf; Wani, Bilal A; Shah, Wajahat A; Bhat, Bilal A; Ganai, Bashir A; Bhat, Khursheed A; Anand, Rajneesh; Qurishi, Mushtaq A

2012-10-15

318

Antioxidant and antibacterial activities of bark extracts from Commiphora berryi and Commiphora caudata.  

PubMed

This study investigates the in vitro antioxidant and antimicrobial activities of eight extracts obtained from the dried barks of Commiphora berryi and Commiphora caudata (Burseraceae). The radical scavenging activity was assessed by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide assays. The methanolic extracts of C. berryi and C. caudata showed significant DPPH radical scavenging activity, with IC?? values of 26.92 and 21.16?µg?mL?¹, respectively, and low radical scavenging activity against the nitric oxide assay. The antimicrobial activity of the plants was tested against the Gram-positive and Gram-negative bacteria. The ethyl acetate, chloroform and petroleum ether extracts of C. berryi showed good antibacterial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 0.26?mg?mL?¹, whereas the ethyl acetate and methanol extracts of C. caudata showed moderate antimicrobial activity with an MIC of more than 2.0?mg?mL?¹ against P. aeruginosa compared to the petroleum ether and chloroform extracts, which showed an MIC of 1.1?mg?mL?¹. The methanolic extracts of C. berryi and C. caudata also showed moderate cytotoxic activity against a human mammary carcinoma cell line (MCF-7), with values IC?? of 82.6 and 88.4?µg?mL?¹, respectively. PMID:21416452

Kumari, Ramesh; Meyyappan, Arumugam; Nandi, Debkumar; Agrawalla, Bikram Keshari; Chowdhury, Avik Acharya; Selvamani, Palanisamy; Latha, Subbaiah; Giri, Venkatachalam Sesha; Mukherjee, Joydeep; Bandyopadhyay, Santu; Jaisankar, Parasuraman

2011-09-01

319

Chemical composition and antibacterial activity of the essential oil from green huajiao (Zanthoxylum schinifolium) against selected foodborne pathogens.  

PubMed

Green huajiao, which is the ripe pericarp of the fruit of Zanthoxylum schinifolium Sieb. et Zucc, is widely consumed in Asia as a spice. In this work, the chemical composition of the essential oil from green huajiao was analyzed by gas chromatography (GC) and GC/mass spectrometry (MS), and the majority of components were identified. Linalool (28.2%), limonene (13.2%), and sabinene (12.1%) were found to be the major components. The antibacterial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of the essential oil were evaluated against selected bacteria, including food-borne pathogens. The results showed that the sensitivities to the essential oil were different for different bacteria tested, and the susceptibility of Gram-positive bacteria tested was observed to be greater than that of Gram-negative bacteria. The antibacterial activity of the essential oil was particularly strong against Staphylococcus epidermidis , with MIC and MBC values of 2.5 and 5.0 mg/mL, respectively. A postcontact effect assay also confirmed the essential oil had a significant effect on the growth rate of surviving S. epidermidis . The antibacterial activity of the essential oil from green huajiao may be due to the increase in permeability of cell membranes, and the leakage of intracellular constituents, on the basis of the cell constituents' release assay and electron microscopy observations. PMID:23758080

Diao, Wen-Rui; Hu, Qing-Ping; Feng, Sai-Sai; Li, Wei-Qin; Xu, Jian-Guo

2013-06-26

320

Injectable bioadhesive hydrogels with innate antibacterial properties.  

PubMed

Surgical site infections cause significant postoperative morbidity and increased healthcare costs. Bioadhesives used to fill surgical voids and support wound healing are typically devoid of antibacterial activity. Here we report novel syringe-injectable bioadhesive hydrogels with inherent antibacterial properties prepared from mixing polydextran aldehyde and branched polyethylenimine. These adhesives kill both Gram-negative and Gram-positive bacteria, while sparing human erythrocytes. An optimal composition of 2.5?wt% oxidized dextran and 6.9?wt% polyethylenimine sets within seconds forming a mechanically rigid (~\

Giano, Michael C; Ibrahim, Zuhaib; Medina, Scott H; Sarhane, Karim A; Christensen, Joani M; Yamada, Yuji; Brandacher, Gerald; Schneider, Joel P

2014-01-01

321

Potent and broad-spectrum antibacterial activity of indole-based bisamidine antibiotics: synthesis and SAR of novel analogs of MBX 1066 and MBX 1090.  

PubMed

The prevalence of drug-resistant bacteria in the clinic has propelled a concerted effort to find new classes of antibiotics that will circumvent current modes of resistance. We have previously described a set of bisamidine antibiotics that contains a core composed of two indoles and a central linker. The first compounds of the series, MBX 1066 and MBX 1090, have potent antibacterial properties against a wide range of Gram-positive and Gram-negative bacteria. We have conducted a systematic exploration of the amidine functionalities, the central linker, and substituents at the indole 3-position to determine the factors involved in potent antibacterial activity. Some of the newly synthesized compounds have even more potent and broad-spectrum activity than MBX 1066 and MBX 1090. PMID:24239389

Williams, John D; Nguyen, Son T; Gu, Shen; Ding, Xiaoyuan; Butler, Michelle M; Tashjian, Tommy F; Opperman, Timothy J; Panchal, Rekha G; Bavari, Sina; Peet, Norton P; Moir, Donald T; Bowlin, Terry L

2013-12-15

322

Antibacterial Activity of Leptadenia reticulata (Retz.) Wight. & Arn. (Asclepidaceae)  

PubMed Central

Leptadenia reticulata of Asclepidaceae family is a shrub, originally property of Petroleum ether, Alcohol & Chloroform extract of L. reticulata. The antimicrobial testing was carried out by “Disc diffusion method”. Amongst the tested three extracts, chloroform extract showed high antimicrobial activity against E. coli, alcoholic extract showed high antibacterial activity against Pseudomonas aeruginosa, while Petroleum ether extract showed antibacterial activity against Klebsilla pneumonae

Kalidass, C.; Glory, M.; Borgio, Francis; Manickam, V S

2009-01-01

323

Antibacterial Activity of Leptadenia reticulata (Retz.) Wight. & Arn. (Asclepidaceae).  

PubMed

Leptadenia reticulata of Asclepidaceae family is a shrub, originally property of Petroleum ether, Alcohol & Chloroform extract of L. reticulata. The antimicrobial testing was carried out by "Disc diffusion method". Amongst the tested three extracts, chloroform extract showed high antimicrobial activity against E. coli, alcoholic extract showed high antibacterial activity against Pseudomonas aeruginosa, while Petroleum ether extract showed antibacterial activity against Klebsilla pneumonae. PMID:22557325

Kalidass, C; Glory, M; Borgio, Francis; Manickam, V S

2009-04-01

324

Wound-dressing materials with antibacterial activity from electrospun polyurethane-dextran nanofiber mats containing ciprofloxacin HCl.  

PubMed

Dextran is a versatile biomacromolecule for preparing electrospun nanofibrous membranes by blending with either water-soluble bioactive agents or hydrophobic biodegradable polymers for biomedical applications. In this study, an antibacterial electrospun scaffold was prepared by electrospinning of a solution composed of dextran, polyurethane (PU) and ciprofloxacin HCl (CipHCl) drug. The obtained nanofiber mats have good morphology. The mats were characterized by various analytical techniques. The interaction parameters between fibroblasts and the PU-dextran and PU-dextran-drug scaffolds such as viability, proliferation, and attachment were investigated. The results indicated that the cells interacted favorably with the scaffolds especially the drug-containing one. Moreover, the composite mat showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. Overall, our results conclude that the introduced scaffold might be an ideal biomaterial for wound dressing applications. PMID:22944448

Unnithan, Afeesh R; Barakat, Nasser A M; Pichiah, P B Tirupathi; Gnanasekaran, Gopalsamy; Nirmala, R; Cha, Youn-Soo; Jung, Che-Hun; El-Newehy, Mohamed; Kim, Hak Yong

2012-11-01

325

Tissue Factor Pathway Inhibitor 2 Is Found in Skin and Its C-Terminal Region Encodes for Antibacterial Activity  

PubMed Central

Background Tissue factor pathway inhibitor 2 (TFPI-2) is a matrix-associated serine protease inhibitor with an enigmatic function in vivo. Here, we describe that TFPI-2 is present in fibrin of wounds and also expressed in skin, where it is up-regulated upon wounding. Methodology and Principal Findings Neutrophil elastase cleaved TFPI-2, and a C-terminal fragment was found to bind to bacteria. Similarly, a prototypic peptide representing this C-terminal part, EDC34, bound to bacteria and bacterial lipopolysaccharide, and induced bacterial permeabilization. The peptide also induced leakage in artificial liposomes, and displayed a random coil conformation upon interactions with liposomes as well as lipopolysaccharide. EDC34 was antibacterial against both Gram-negative and Gram-positive bacteria in physiological buffer conditions. Conclusions/Significance The results demonstrate that the C-terminus of TFPI-2 encodes for antimicrobial activity, and may be released during wounding.

Papareddy, Praveen; Kalle, Martina; S?rensen, Ole E.; Lundqvist, Katarina; Morgelin, Matthias; Malmsten, Martin; Schmidtchen, Artur

2012-01-01

326

Chemical composition, antibacterial and antifungal activities of essential oil from Cordia verbenacea DC leaves  

PubMed Central

Background: Cordia verbenacea is a Brazilian coastal shrub popularly known as “erva baleeira”. The essential oil from fresh leaves was obtained by hydrodistillation and analyzed by CG/MS. The main components were identified as ?-caryophyllene (25.4%), bicyclogermacrene (11.3%), ?-cadinene (9.%) and ?-pinene (9.5%). In this study, the antimicrobial activity of Cordia verbenacea was evaluated. Materials and Methods: The minimal inhibitory concentration (MIC) of the essential oil was obtained using the broth microdilution assay (from 512 to 8 ?g/ml). Results: The results showed that the essential oil presented fungistatic activity against Candida albicans and Candida krusei and antibacterial activity against Gram-positive strains (Staphylococcus aureus and Bacillus cereus) and against multiresistant Gram-negative (Escherichia coli 27), in all tests the MIC was 64 ?g/ml. When the essential oil was associated to aminoglycosides (subinhibitory concentrations, MIC/8), a synergic and antagonic activity was verified. The synergic effect was observed to the amikacin association (MIC reduction from 256 mlto 64 ?g/ml) in all strains tested. Conclusion: The essential oil of Cordia verbenacea influences the activity of antibiotics and may be used as an adjuvant in antibiotic therapy against respiratory tract bacterial pathogens.

Rodrigues, Fabiola F. G.; Oliveira, Liana G. S.; Rodrigues, Fabio F. G.; Saraiva, Manuele E.; Almeida, Sheyla C. X.; Cabral, Mario E. S.; Campos, Adriana R.; Costa, Jose Galberto M.

2012-01-01

327

[Determination of the antibacterial and antiviral activity of the essential oil from Minthostachys verticillata (Griseb.) Epling].  

PubMed

The in vitro antiviral activity of the essential oil from Minthostachys verticillata was investigated against herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PrV). The viral inhibition was assayed employing viral plaque reduction assay. The antiviral activity of the essential oil specifically affects PrV and HSV-1 multiplication, since it was found that non toxic effects on cells were observed at the concentrations assayed. The therapeutic index values were 10.0 and 9.5 for HSV-1 and PrV, respectively. The antibacterial activity was studied using a diffusion assay and the broth tube dilution method. Gram-positive bacteria were more sensitive to inhibition by plant essential oil than the gram-negative bacteria. The essential oil of M. verticillata was analyzed by gas chromatography (GC) technique. Of the six components identified in the volatile oil, pulegone (44.56%) and menthone (39.51%) were the major constituents. The antimicrobial activity can be explained to some extent by the presence of pulegone. Results suggest that further investigations concerning the isolation of the substance responsible for the antimicrobial activity and an effort to define the mechanisms of action are warranted. PMID:11494754

Primo, V; Rovera, M; Zanon, S; Oliva, M; Demo, M; Daghero, J; Sabini, L

2001-01-01

328

Di-alkylated paromomycin derivatives: targeting the membranes of gram positive pathogens that cause skin infections.  

PubMed

A collection of paromomycin-based di-alkylated cationic amphiphiles differing in the lengths of their aliphatic chain residues were designed, synthesized, and evaluated against 14 Gram positive pathogens that are known to cause skin infections. Paromomycin derivatives that were di-alkylated with C7 and C8 linear aliphatic chains had improved antimicrobial activities relative to the parent aminoglycoside as well as to the clinically used membrane-targeting antibiotic gramicidin D; several novel derivatives were at least 16-fold more potent than the parent aminoglycoside paromomycin. Comparison between a di-alkylated and a mono-alkylated paromomycin indicated that the di-alkylation strategy leads to both an improvement in antimicrobial activity and to a dramatic reduction in undesired red blood cell hemolysis caused by many aminoglycoside-based cationic amphiphiles. Scanning electron microscopy provided evidence for cell surface damage by the reported di-alkylated paromomycins. PMID:23602621

Berkov-Zrihen, Yifat; Herzog, Ido M; Feldman, Mark; Sonn-Segev, Adar; Roichman, Yael; Fridman, Micha

2013-06-15

329

Studies on the aminopeptidase test for the distinction of gram-negative from gram-positive bacteria  

Microsoft Academic Search

The aminopeptidase test was performed with representatives of gram-negative, gram-positive, and gram-variable bacteria. All gram-negative bacteria tested gave a positive test reaction with L-alanine-4-nitroanilide as test substrate. Representatives of the coryneform bacteria and some streptococci showed aminopeptidase activity after prolonged reaction times. A correlation between aminopeptidase activity and distinct interpeptide bridge composition in the peptidoglycan of many strains was demonstrated.

G. Cerny

1978-01-01

330

Cytotoxicity and antibacterial activity of extractives from Wedelia calendulacea  

Microsoft Academic Search

The cytotoxicity and antibacterial activity of petroleum ether, chloroform and methanol extracts of Wedelia calendulacea were assayed by brine shrimp lethality bioassay and standardized disk diffusion method against 19 bacterial strains. Three diterpenes isolated from the plant were also evaluated for in vitro antibacterial activities. The LC50 for the crude extracts against the brine shrimp nauplii were found to be

A. K. M Mottakin; R Chowdhury; M. S Haider; K. M Rahman; C. M Hasan; M. A Rashid

2004-01-01

331

Screening of some Palestinian medicinal plants for antibacterial activity  

Microsoft Academic Search

Antibacterial activity of organic and aqueous extracts of 15 Palestinian medicinal plants were carried against eight different species of bacteria: Bacillus subtilis, two Escherichia coli species, Staphylococcus aureus (methicillin resistant), two S. aureus (methicillin sensitive) species, Pseudomonas aeruginosa, and Enterococcus fecalis. Of the 15 plants tested, eight showed antibacterial activity. Each plant species has unique against different bacteria. The most

T Essawi; M Srour

2000-01-01

332

In vitro Antioxidant and Antibacterial Activities of Methanol Extract of Kyllinga nemoralis  

PubMed Central

The present study was designed to evaluate the antioxidant and antibacterial activity of methanol extract of Kyllinga nemoralis. Six different in vitro antioxidant assays including 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical, superoxide anion radical, hydrogen peroxide radical, ferric reducing antioxidant power assay and reducing power were carried out to ensure the scavenging effect of the plant on free radicals. In addition, total antioxidant capacity assay, total phenolic contents, tannins, flavonoids and flavonol contents of the plant were also analysed by the standard protocols. Kyllinga nemoralis exhibited high antioxidant activity on 2,2-diphenyl-1-picrylhydrazyl assay (IC50= 90 ?g/ml), superoxide radical scavenging assay (IC50= 180 ?g/ml) and hydrogen peroxide radical scavenging assay (IC50= 200 ?g/ml), compared with standards. These observations provide comprehensible supporting evidence for the antioxidant potential of the plant extract. Reducing power (IC50= 213.16 ?g/ml) and hydroxyl radical scavenging activity (IC50= 223 ?g/ml) of the plant extract was remarkable. The methanol extract of K. nemoralis exhibited significant antimicrobial activity against Gram-positive human pathogenic bacteria. Standard in vitro antioxidant assays assessed the electron donating ability of the plant extract in scavenging free radicals. The inhibitory effect of the plant extract against bacterial pathogens may be due to the presence of phytochemicals. Thus, the results suggest that Kyllinga nemoralis is a potential source of antioxidants and could serve as the base for drug development.

Sindhu, T.; Rajamanikandan, S.; Srinivasan, P.

2014-01-01

333

Saccharomicins, novel heptadecaglycoside antibiotics produced by Saccharothrix espanaensis: antibacterial and mechanistic activities.  

PubMed

Saccharomicins A and B, two new heptadecaglycoside antibiotics, were isolated from the fermentation broth of the rare actinomycete Saccharothrix espanaensis. They represent a novel class of bactericidal antibiotics that are active both in vitro and in vivo against bacteria and yeast (MICs: Staphylococcus aureus, <0.12 to 0. 5; vancomycin-resistant enterococci, 0.25 to 16; gram-negative bacteria, 0.25 to >128; and yeast, >128 microg/ml), including multiply resistant strains. Saccharomicins protected mice from lethal challenges by staphylococci (subcutaneous 50% effective dose range of 0.06 to 2.6 mg/kg of body weight, depending on the S. aureus strain). The 50% lethal dose by the subcutaneous route was 16 mg/kg. Mechanistic studies with Escherichia coli imp and Bacillus subtilis suggested complete, nonspecific inhibition of DNA, RNA, and protein biosynthesis within 10 min of drug treatment. Microscopic examination of drug-treated cells also suggested cell lysis. These data are consistent with a strong membrane-disruptive activity. The antibacterial activities of the saccharomicins against gram-positive bacteria were unaffected by the presence of Ca(2+) or Mg(2+), but activity against gram-negative bacteria was substantially reduced. PMID:10898690

Singh, M P; Petersen, P J; Weiss, W J; Kong, F; Greenstein, M

2000-08-01

334

Saccharomicins, Novel Heptadecaglycoside Antibiotics Produced by Saccharothrix espanaensis: Antibacterial and Mechanistic Activities  

PubMed Central

Saccharomicins A and B, two new heptadecaglycoside antibiotics, were isolated from the fermentation broth of the rare actinomycete Saccharothrix espanaensis. They represent a novel class of bactericidal antibiotics that are active both in vitro and in vivo against bacteria and yeast (MICs: Staphylococcus aureus, <0.12 to 0.5; vancomycin-resistant enterococci, 0.25 to 16; gram-negative bacteria, 0.25 to >128; and yeast, >128 ?g/ml), including multiply resistant strains. Saccharomicins protected mice from lethal challenges by staphylococci (subcutaneous 50% effective dose range of 0.06 to 2.6 mg/kg of body weight, depending on the S. aureus strain). The 50% lethal dose by the subcutaneous route was 16 mg/kg. Mechanistic studies with Escherichia coli imp and Bacillus subtilis suggested complete, nonspecific inhibition of DNA, RNA, and protein biosynthesis within 10 min of drug treatment. Microscopic examination of drug-treated cells also suggested cell lysis. These data are consistent with a strong membrane-disruptive activity. The antibacterial activities of the saccharomicins against gram-positive bacteria were unaffected by the presence of Ca2+ or Mg2+, but activity against gram-negative bacteria was substantially reduced.

Singh, M. P.; Petersen, P. J.; Weiss, W. J.; Kong, F.; Greenstein, M.

2000-01-01

335

Antibacterial and antioxidant activities of the essential oil of Artemisia echegarayi Hieron. (Asteraceae).  

PubMed

Artemisia echegarayi Hieron. (Asteraceae) is commonly known in Argentina as "ajenjo". Many studies report high efficacy of essential oils against food-borne pathogenic bacteria. The antimicrobial activity and minimal inhibitory concentration of A. echegarayi essential oil were evaluated against seven bacterial species of significant importance in food hygiene, by using the disc diffusion assay and the micro-well dilution method, respectively. Volatile components of the extract were analyzed by gas chromatography-mass spectrometry and major components were determined. Furthermore, the essential oil was tested for its antioxidant activity. The essential oil inhibited the growth of gram-positive and gram-negative tested bacteria, with the exception of Proteus mirabilis. A. echegarayi essential oil presented the lowest minimal inhibitory concentration against Listeria monocytogenes and Bacillus cereus. Two terpenes, thujone and camphor, were identified from this essential oil as the principal constituents responsible for antibacterial activity. The oil showed a free radical scavenging activity equivalent to 50% of the reference compound. These preliminary studies showed promising results since this essential oil may provide an alternative to promote its use as a natural food additive. PMID:20085186

Laciar, A; Ruiz, M L Vaca; Flores, R Carrizo; Saad, J R

2009-01-01

336

Antibacterial Activity of Eravacycline (TP-434), a Novel Fluorocycline, against Hospital and Community Pathogens  

PubMed Central

Eravacycline (TP-434 or 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline) is a novel fluorocycline that was evaluated for antimicrobial activity against panels of recently isolated aerobic and anaerobic Gram-negative and Gram-positive bacteria. Eravacycline showed potent broad-spectrum activity against 90% of the isolates (MIC90) in each panel at concentrations ranging from ?0.008 to 2 ?g/ml for all species panels except those of Pseudomonas aeruginosa and Burkholderia cenocepacia (MIC90 values of 32 ?g/ml for both organisms). The antibacterial activity of eravacycline was minimally affected by expression of tetracycline-specific efflux and ribosomal protection mechanisms in clinical isolates. Furthermore, eravacycline was active against multidrug-resistant bacteria, including those expressing extended-spectrum ?-lactamases and mechanisms conferring resistance to other classes of antibiotics, including carbapenem resistance. Eravacycline has the potential to be a promising new intravenous (i.v.)/oral antibiotic for the empirical treatment of complicated hospital/health care infections and moderate-to-severe community-acquired infections.

O'Brien, W.; Fyfe, C.; Grossman, T. H.

2013-01-01

337

Antibacterial activity of Artemisia nilagirica leaf extracts against clinical and phytopathogenic bacteria  

PubMed Central

Background The six organic solvent extracts of Artemisia nilagirica were screened for the potential antimicrobial activity against phytopathogens and clinically important standard reference bacterial strains. Methods The agar disk diffusion method was used to study the antibacterial activity of A. nilagirica extracts against 15 bacterial strains. The Minimum Inhibitory Concentration (MIC) of the plant extracts were tested using two fold agar dilution method at concentrations ranging from 32 to 512 ?g/ml. The phytochemical screening of extracts was carried out for major phytochemical derivatives in A. nilagirica. Results All the extracts showed inhibitory activity for gram-positive and gram-negative bacteria except for Klebsiella pneumoniae, Enterococcus faecalis and Staphylococcus aureus. The hexane extract was found to be effective against all phytopathogens with low MIC of 32 ?g/ml and the methanol extract exhibited a higher inhibition activity against Escherichia coli, Yersinia enterocolitica, Salmonella typhi, Enterobacter aerogenes, Proteus vulgaris, Pseudomonas aeruginosa (32 ?g/ml), Bacillus subtilis (64 ?g/ml) and Shigella flaxneri (128 ?g/ml). The phytochemical screening of extracts answered for the major derivative of alkaloids, amino acids, flavonoids, phenol, quinines, tannins and terpenoids. Conclusion All the extracts showed antibacterial activity against the tested strains. Of all, methanol and hexane extracts showed high inhibition against clinical and phytopathogens, respectively. The results also indicate the presence of major phytochemical derivatives in the A. nilagirica extracts. Hence, the isolation and purification of therapeutic potential compounds from A. nilagirica could be used as an effective source against bacterial diseases in human and plants.

2010-01-01

338

Sonodynamic Excitation of Rose Bengal for Eradication of Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Photodynamic antimicrobial chemotherapy based on photosensitizers activated by illumination is limited by poor penetration of visible light through skin and tissues. In order to overcome this problem, Rose Bengal was excited in the dark by 28?kHz ultrasound and was applied for inactivation of bacteria. It is demonstrated, for the first time, that the sonodynamic technique is effective for eradication of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The net sonodynamic effect was calculated as a 3-4 log10 reduction in bacteria concentration, depending on the cell and the Rose Bengal concentration and the treatment time. Sonodynamic treatment may become a novel and effective form of antimicrobial therapy and can be used for low-temperature sterilization of medical instruments and surgical accessories.

Nakonechny, Faina; Nisnevitch, Michael; Nitzan, Yeshayahu; Nisnevitch, Marina

2013-01-01

339

In Vitro Antibacterial Activity of Essential Oils against Streptococcus pyogenes.  

PubMed

Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred. PMID:23662123

Sfeir, Julien; Lefrançois, Corinne; Baudoux, Dominique; Derbré, Séverine; Licznar, Patricia

2013-01-01

340

In Vitro Antibacterial Activity of Essential Oils against Streptococcus pyogenes  

PubMed Central

Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred.

Sfeir, Julien; Lefrancois, Corinne; Baudoux, Dominique; Derbre, Severine; Licznar, Patricia

2013-01-01

341

Antioxidant and antibacterial activities of the leaf essential oils of Himalayan Lauraceae species.  

PubMed

The leaf essential oils from seven Himalayan Lauraceae species viz. Neolitsea pallens, Lindera pulcherrima, Dodecadenia grandiflora, Persea duthiei, Persea odoratissima, Persea gamblei and Phoebe lanceolata exhibited potent antioxidant and antibacterial activities. The in vitro antioxidant activity was assessed by using beta-carotene bleaching assay, reducing power, DPPH radical scavenging and inhibition of lipid peroxidation methods. The oils of D. grandiflora and L. pulcherrima showed a potent free radical scavenging activity as evidenced by low IC(50) value for DPPH radical (0.032 mg/ml and 0.087 mg/ml, respectively) and inhibition of lipid peroxidation (in between IC(50)=0.44 mg/ml and IC(50)=0.74 mg/ml, respectively). The oils were tested against three Gram negative (Escherichia coli, Salmonella enterica enterica and Pasturella multocida) and one Gram positive (Staphylococcus aureus) bacteria at different concentrations using disc diffusion and tube dilution methods. The inhibition zones (IZ) and MIC values for bacterial strains were in the range of 8.7-22.0mm and 3.90-31.25 microl/ml, respectively. PMID:19766161

Joshi, Subhash C; Verma, Arti R; Mathela, Chandra S

2010-01-01

342

Comparison of the D-Glutamate-Adding Enzymes from Selected Gram-Positive and Gram-Negative Bacteria  

Microsoft Academic Search

The biochemical properties of the D-glutamate-adding enzymes (MurD) from Escherichia coli, Haemophilus influenzae, Enterococcus faecalis, and Staphylococcus aureus were investigated to detect any differences in the activity of this enzyme between gram-positive and gram-negative bacteria. The genes (murD) that encode these enzymes were cloned into pMAL-c2 fusion vector and overexpressed as maltose-binding protein-MurD fusion proteins. Each fusion protein was purified

ANN W. WALSH; PAUL J. FALK; JANE THANASSI; LINDA DISCOTTO; MICHAEL J. PUCCI; HSU-TSO HO

1999-01-01

343

Coexistence of CD14Dependent and Independent Pathways for Stimulation of Human Monocytes by Gram-Positive Bacteria  

Microsoft Academic Search

The cell wall is a key inflammatory agent of gram-positive bacteria. Possible receptors mediating cell wall-induced inflammation include CD14 and platelet-activating factor (PAF) receptor. To delineate the conditions under which these various receptors might be used, human monocytic THP-1 cells and heparinized whole human blood were stimulated with lipopolysaccharide (LPS), intact Streptococcus pneumoniae bacteria, or purified pneumococcal cell wall. THP-1

ANJE CAUWELS; ELAINE WAN; MICHAELA LEISMANN; ELAINE TUOMANEN

1997-01-01

344

Temporin-SHa peptides grafted on gold surfaces display antibacterial activity.  

PubMed

Development of resistant bacteria onto biomaterials is a major problem leading to nosocomial infections. Antimicrobial peptides are good candidates for the generation of antimicrobial surfaces because of their broad-spectrum activity and their original mechanism of action (i.e. rapid lysis of the bacterial membrane) making them less susceptible to the development of bacterial resistance. In this study, we report on the covalent immobilisation of temporin-SHa on a gold surface modified by a thiolated self-assembled monolayer. Temporin-SHa (FLSGIVGMLGKLFamide ) is a small hydrophobic and low cationic antimicrobial peptide with potent and very broad-spectrum activity against Gram-positive and Gram-negative bacteria, yeasts and parasites. We have analysed the influence of the binding mode of temporin-SHa on the antibacterial efficiency by using a covalent binding either via the peptide NH2 groups (random grafting of ?- and ?-NH2 to the surface) or via its C-terminal end (oriented grafting using the analogue temporin-SHa-COOH). The surface functionalization was characterised by IR spectroscopy (polarisation modulation reflection absorption IR spectroscopy) while antibacterial activity against Listeria ivanovii was assessed by microscopy techniques, such as atomic force microscopy and scanning electron microscopy equipped with a field emission gun. Our results revealed that temporin-SHa retains its antimicrobial activity after covalent grafting. A higher amount of bound temporin-SHa is observed for the C-terminally oriented grafting compared with the random grafting (NH2 groups). Temporin-SHa therefore represents an attractive candidate as antimicrobial coating agent. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. PMID:24919960

Lombana, Andres; Raja, Zahid; Casale, Sandra; Pradier, Claire-Marie; Foulon, Thierry; Ladram, Ali; Humblot, Vincent

2014-07-01

345

Evaluation of antibacterial activity of N-phosphonium chitosan as a novel polymeric antibacterial agent.  

PubMed

N-phosphonium chitosans (NPCSs) with different degrees of substitution (3%, 13% and 21%) were synthesized and evaluated as novel polymeric antibacterial agents. Their antibacterial activities compared with hydroxypropyltrimethyl ammonium chloride chitosan (HACC), parent chitosan and (5-carboxypentyl) triphenylphosphonium bromide (CTPB) were tested against Escherichia coli and two strains of drug-resistance Staphylococcus aureus by minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and biofilm prevention assays. The results show that the NPCS with 3% or 13% substitution has lower MIC and MBC values and stronger ability to inhibit biofilm formation of all the three bacteria than HACC, chitosan and CTPB. In addition, the antibacterial activity of NPCSs increases with their substitution decreasing from 21% to 3%. Overall, the antibacterial activity of NPCS with 3% or 13% substitution is better than that of NPCS with 21% substitution, HACC with 22% substitution, chitosan and CTPB. It can be considered that NPCS with appropriate degree of substitution has favorable antibacterial activity and is a potential polymeric antibacterial agent. PMID:24680902

Guo, Aijie; Wang, Feihu; Lin, Wentao; Xu, Xiaofen; Tang, Tingting; Shen, Yuanyuan; Guo, Shengrong

2014-06-01

346

Synthesis, structure and structure-activity relationship analysis of 3-tert-butoxycarbonyl-2-arylthiazolidine-4-carboxylic acid derivatives as potential antibacterial agents.  

PubMed

Nine 2-arylthiazolidine-4-carboxylic acid derivatives and nine 3-tert-butoxycarbonyl-2-arylthiazolidine-4-carboxylic acid derivatives were synthesized to screen for their antibacterial activities. Compounds 5, 14-18 were first reported. Their chemical structures were clearly determined by (1)H NMR, (13)C NMR, ESI mass spectra and elemental analyses, coupled with one selected single-crystal structure. All the compounds were assayed for antibacterial activities against two Gram-positive bacterial strains (Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 6538) and two Gram-negative bacterial strains (Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 13525) by MTT method. Most of the 3-tert-butoxycarbonyl-2-arylthiazolidine-4-carboxylic acid derivatives exhibited better antibacterial activities against the four bacterial strains than relative 2-arylthiazolidine-4-carboxylic acid derivatives. Compound (2RS,4R)-3-(tert-butoxycarbonyl)-2-(5-fluoro-2-hydroxyphenyl)thiazolidine-4-carboxylic acid (14) showed powerful antibacterial activities against P. aeruginosa with IC(50) value of 0.195 microg/mL, which was superior to the positive controls Penicillin G and Kanamycin B, respectively. On the basis of the biological results, structure-activity relationships were discussed. PMID:19423200

Song, Zhong-Cheng; Ma, Gao-Yuan; Lv, Peng-Cheng; Li, Huan-Qiu; Xiao, Zhu-Ping; Zhu, Hai-Liang

2009-10-01

347

Environmentally friendly antibacterial cotton textiles finished with siloxane sulfopropylbetaine.  

PubMed

This paper reports a novel environmentally friendly antibacterial cotton textile finished with reactive siloxane sulfopropylbetaine(SSPB). The results show that SSPB can be covalently bound onto the cotton textile surface, imparting perdurable antibacterial activity. The textiles finished with SSPB have been investigated systematically from the mechanical properties, thermal stability, hydrophilic properties and antibacterial properties. It is found that the hydrophilicity and breaking strength are improved greatly after the cotton textiles are finished with SSPB. Additionally, the cotton textiles finished with SSPB exhibit good antibacterial activities against gram-positive bacteria Staphylococcus aureus (S.aureus, ATCC 6538), gram-negative bacteria Escherichia coli (E.coli, 8099) and fungi Candida albicans (C.albicans, ATCC 10231). Moreover, SSPB is nonleachable from the textiles, and it does not induce skin stimulation and is nontoxic to animals. Thus, SSPB is ideal candidate for environmentally friendly antibacterial textile applications. PMID:21417413

Chen, Shiguo; Chen, Shaojun; Jiang, Song; Xiong, Meiling; Luo, Junxuan; Tang, Jiaoning; Ge, Zaochuan

2011-04-01

348

Extracellular vesicles produced by the Gram-positive bacterium Bacillus subtilis are disrupted by the lipopeptide surfactin.  

PubMed

Previously, extracellular vesicle production in Gram-positive bacteria was dismissed due to the absence of an outer membrane, where Gram-negative vesicles originate, and the difficulty in envisioning how such a process could occur through the cell wall. However, recent work has shown that Gram-positive bacteria produce extracellular vesicles and that the vesicles are biologically active. In this study, we show that Bacillus subtilis produces extracellular vesicles similar in size and morphology to other bacteria, characterized vesicles using a variety of techniques, provide evidence that these vesicles are actively produced by cells, show differences in vesicle production between strains, and identified a mechanism for such differences based on vesicle disruption. We found that in wild strains of B. subtilis, surfactin disrupted vesicles while in laboratory strains harbouring a mutation in the gene sfp, vesicles accumulated in the culture supernatant. Surfactin not only lysed B. subtilis vesicles, but also vesicles from Bacillus anthracis, indicating a mechanism that crossed species boundaries. To our knowledge, this is the first time a gene and a mechanism has been identified in the active disruption of extracellular vesicles and subsequent release of vesicular cargo in Gram-positive bacteria. We also identify a new mechanism of action for surfactin. PMID:24826903

Brown, Lisa; Kessler, Anne; Cabezas-Sanchez, Pablo; Luque-Garcia, Jose L; Casadevall, Arturo

2014-07-01

349

Antibacterial activities of peptides from the water-soluble extracts of Italian cheese varieties.  

PubMed

Water-soluble extracts of 9 Italian cheese varieties that differed mainly for type of cheese milk, starter, technology, and time of ripening were fractionated by reversed-phase fast protein liquid chromatography, and the antimicrobial activity of each fraction was first assayed toward Lactobacillus sakei A15 by well-diffusion assay. Active fractions were further analyzed by HPLC coupled to electrospray ionization-ion trap mass spectrometry, and peptide sequences were identified by comparison with a proteomic database. Parmigiano Reggiano, Fossa, and Gorgonzola water-soluble extracts did not show antibacterial peptides. Fractions of Pecorino Romano, Canestrato Pugliese, Crescenza, and Caprino del Piemonte contained a mixture of peptides with a high degree of homology. Pasta filata cheeses (Caciocavallo and Mozzarella) also had antibacterial peptides. Peptides showed high levels of homology with N-terminal, C-terminal, or whole fragments of well known antimicrobial or multifunctional peptides reported in the literature: alphaS1-casokinin (e.g., sheep alphaS1-casein (CN) f22-30 of Pecorino Romano and cow alphaS1-CN f24-33 of Canestrato Pugliese); isracidin (e.g., sheep alphaS1-CN f10-21 of Pecorino Romano); kappacin and casoplatelin (e.g., cow kappa-CN f106-115 of Canestrato Pugliese and Crescenza); and beta-casomorphin-11 (e.g., goat beta-CN f60-68 of Caprino del Piemonte). As shown by the broth microdilution technique, most of the water-soluble fractions had a large spectrum of inhibition (minimal inhibitory concentration of 20 to 200 microg/mL) toward gram-positive and gram-negative bacterial species, including potentially pathogenic bacteria of clinical interest. Cheeses manufactured from different types of cheese milk (cow, sheep, and goat) have the potential to generate similar peptides with antimicrobial activity. PMID:15956298

Rizzello, C G; Losito, I; Gobbetti, M; Carbonara, T; De Bari, M D; Zambonin, P G

2005-07-01

350

Chemical composition and antibacterial activity of Cordia verbenacea extracts obtained by different methods.  

PubMed

The present study describes the chemical composition and the antibacterial activity of extracts from Cordia verbenacea DC (Borraginaceae), a traditional medicinal plant that grows widely along the southeastern coast of Brazil. The extracts were obtained using different extraction techniques: high-pressure operations and low-pressure methods. The high-pressure technique was applied to obtain C. verbenacea extracts using pure CO(2) and CO(2) with co-solvent at pressures up to 30MPa and temperatures of 30, 40 and 50 degrees C. Organic solvents such as n-hexane, ethyl acetate, ethanol, acetone and dichloromethane were used to obtain extracts by low-pressure processes. The antibacterial activity of the extracts was also subjected to screening against four strains of bacteria using the agar dilution method. The extraction yields were up to 5.0% w/w and up to 8.6% w/w for supercritical fluid extraction with pure CO(2) and with ethyl acetate as co-solvent, respectively, while the low-pressure extraction indicates yields up to 24.0% w/w in the soxhlet extraction using water and aqueous mixture with 50% ethanol as solvents. The inhibitory activity of the extracts in gram-positive bacteria was significantly higher than in gram-negative. The quantification and the identification of the extracts recovered were accomplished using GC/MS analysis. The most important components identified in the extract were artemetin, beta-sitosterol, alpha-humulene and beta-caryophyllene, among others. PMID:19683436

Michielin, Eliane M Z; Salvador, Ana A; Riehl, Carlos A S; Smânia, Artur; Smânia, Elza F A; Ferreira, Sandra R S

2009-12-01

351

Cationic amphiphilic non-hemolytic polyacrylates with superior antibacterial activity.  

PubMed

Acrylic copolymers with appropriate compositions of counits having cationic charge with 2-carbon and 6-carbon spacer arms can show superior antibacterial activities with concomitant very low hemolytic effect. These amphiphilic copolymers represent one of the most promising synthetic polymer antibacterial systems reported. PMID:24854366

Punia, Ashish; He, Edward; Lee, Kevin; Banerjee, Probal; Yang, Nan-Loh

2014-06-01

352

Phylogenetic diversity of Gram-positive bacteria cultured from Antarctic deep-sea sponges  

Microsoft Academic Search

Gram-positive bacteria, specifically actinobacteria and members of the order Bacillales, are well-known producers of important\\u000a secondary metabolites. Little is known about the diversity of Gram-positive bacteria associated with Antarctic deep-sea sponges.\\u000a In this study, cultivation-based approaches were applied to investigate the Gram-positive bacteria associated with the Antarctic\\u000a sponges Rossella nuda, Rossella racovitzae (Porifera: Hexactinellida), and Myxilla mollis, Homaxinella balfourensis, Radiella

Yanjuan Xin; Manmadhan Kanagasabhapathy; Dorte Janussen; Song Xue; Wei Zhang

353

Mechanisms of action of newer antibiotics for Gram-positive pathogens.  

PubMed

Certain Gram-positive bacteria, including meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and quinolone-resistant Streptococcus pneumoniae have achieved the status of "superbugs", in that there are few or no antibiotics available for therapy against these pathogens. Only a few classes of novel antibiotics have been introduced in the past 40 years, and all since 1999, including the streptogramin combination quinupristin/dalfopristin (Synercid), the oxazolidinone linezolid, and the lipopeptide daptomycin. This review discusses the mechanisms of antibiotic action against Gram-positive pathogens, and resistance counter-mechanisms developed by Gram-positive bacteria, with emphasis on the newer agents. PMID:15792738

Hancock, Robert Ew

2005-04-01

354

Surface multiheme c-type cytochromes from Thermincola potens and implications for respiratory metal reduction by Gram-positive bacteria  

PubMed Central

Almost nothing is known about the mechanisms of dissimilatory metal reduction by Gram-positive bacteria, although they may be the dominant species in some environments. Thermincola potens strain JR was isolated from the anode of a microbial fuel cell inoculated with anaerobic digester sludge and operated at 55 °C. Preliminary characterization revealed that T. potens coupled acetate oxidation to the reduction of hydrous ferric oxides (HFO) or anthraquinone-2,6-disulfonate (AQDS), an analog of the redox active components of humic substances. The genome of T. potens was recently sequenced, and the abundance of multiheme c-type cytochromes (MHCs) is unusual for a Gram-positive bacterium. We present evidence from trypsin-shaving LC-MS/MS experiments and surface-enhanced Raman spectroscopy (SERS) that indicates the expression of a number of MHCs during T. potens growth on either HFO or AQDS, and that several MHCs are localized to the cell wall or cell surface. Furthermore, one of the MHCs can be extracted from cells with low pH or denaturants, suggesting a loose association with the cell wall or cell surface. Electron microscopy does not reveal an S-layer, and the precipitation of silver metal on the cell surface is inhibited by cyanide, supporting the involvement of surface-localized redox-active heme proteins in dissimilatory metal reduction. These results provide unique direct evidence for cell wall-associated cytochromes and support MHC involvement in conducting electrons across the cell envelope of a Gram-positive bacterium.

Carlson, Hans K.; Iavarone, Anthony T.; Gorur, Amita; Yeo, Boon Siang; Tran, Rosalie; Melnyk, Ryan A.; Mathies, Richard A.; Auer, Manfred; Coates, John D.

2012-01-01

355

Flavonoids from mango leaves with antibacterial activity  

Microsoft Academic Search

Five flavonoids, viz. (-)-epicatechin-3-O-?-glucopyranoside (1), 5-hy- droxy-3-(4-hydroxylphenyl)pyrano(3,2-g)chromene-4(8H)-one (2), 6-(p-hyd- roxybenzyl)taxifolin-7-O-?-D-glucoside (tricuspid) (3), quercetin-3-O-?-glu- copyranosyl-(1?2)-?-glucopyranoside (4) and (-)-epicatechin(2-(3,4-dihyd- roxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol) (5), were isolated from the leaves of mango (Mangifera indica L.). The antibacterial activity of different concentrations of these flavonoids (100, 300, 500, 700, 900 and 1000 ppm) was evaluated against four bacterial species, namely Lactobacillus sp., Escherichia coli, Azospirillium lipoferum and

Qudsia Kanwal; Ishtiaq Hussain; HAMID LATIF SIDDIQUI; Arshad Javaid

2009-01-01

356

Investigation of 5-nitrofuran derivatives: synthesis, antibacterial activity, and quantitative structure-activity relationships.  

PubMed

Three sets of antibacterial nitrofuran derivatives [set I, 5-R-substituted (Z)-2-(5-nitrofuran-2-ylmethylene)-3(2H)-benzofuranones (R = OCH(3), H, CH(3), C(2)H(5), nC(3)H(7), Cl, Br, CN, and NO(2)) and their 2-hydroxyphenyl and 2-acetoxyphenyl analogues; set II, 5-R-substituted (E)-1-(2-hydroxyphenyl)-3-(5-nitrofuryl)-2-propen-1-ones (R = H, CH(3), C(2)H(5), Cl, and NO(2)); and set III, 5-R-substituted (E)-1-(2-acetoxyphenyl)-3-(5-nitrofuryl)-2-propen-1-ones (R = H, CH(3); C(2)H(5), Cl, and NO(2))] were prepared and tested against a Gram-positive (Staphylococcus aureus, strain ATCC-25923) and a Gram-negative bacterium (Caulobacter crescentus, strain NA 1000). QSAR equations derived for the IC(50) values against both bacteria show negative contributions of two terms: an electronic one, expressed either by sigma, the Hammett substituent constant, or by E, the cyclic voltametric reduction potential. Another term described by an indicator variable, I(abs), is assigned the value of 0 for set I compounds and the value of 1 for sets II and III. No important contribution of the hydrophobic factor was found. For the three sets, the QSAR regressions suggest that the same structural features describe the activities for both bacteria and that, although reduction is a necessary step, it should not be the determining one. These results agree with those found for the QSAR of 5-nitroimidazole analogues. PMID:11606132

Pires, J R; Saito, C; Gomes, S L; Giesbrecht, A M; Amaral, A T

2001-10-25

357

Phytogrowth-inhibitory and antibacterial activity of Verbascum sinuatum.  

PubMed

The methanolic extract of Verbascum sinuatum inflorescences and isolated compounds were tested for their antibacterial activity against 13 Gram(+) and Gram(-) bacteria and for their allelopathic activity against radish. PMID:17341439

Senatore, Felice; Rigano, Daniela; Formisano, Carmen; Grassia, Armando; Basile, Adriana; Sorbo, Sergio

2007-04-01

358

Performance of the Verigene Gram-Positive Blood Culture Assay for Direct Detection of Gram-Positive Organisms and Resistance Markers in a Pediatric Hospital  

PubMed Central

The performance characteristics of the Verigene Gram-positive blood culture (BC-GP) assay were evaluated in pediatric patients. Concordance of the BC-GP assay was 95.8%, with significant decreases in turnaround time for identification and resistance detection. BC-GP is highly accurate and can be integrated into the routine workflow of the microbiology laboratory.

Mestas, Javier; Polanco, Claudia M.; Felsenstein, Susanna

2014-01-01

359

Preparation of an antibacterial peptide bovine lactoferricin by genetic engineering  

Microsoft Academic Search

Lactoferricin (Lfcin) is an amphipathic and cationic peptide with strong antibacterial activities against a broad range of Gram-positive, Gram-negative bacteria. It is usually generated by the pepsin-mediated digestion of lactoferrin. This paper investigated the potential for production of bovine lactoferricin (LfcinB) through genetic engineering. Three primers were designed according to amino acid sequence of bovine lactoferricin and then used to

Qiang Deng; Bate; Zhuoping Ding; Chengchu Liu; Jianzhang Lu

2010-01-01

360

Surface multiheme c-type cytochromes from Thermincola potens: Implications for dissimilatory metal reduction by Gram-positive bacteria  

NASA Astrophysics Data System (ADS)

Almost nothing is known about the mechanisms of dissimilatory metal reduction by Gram-positive bacteria, although they have been shown to be the dominant species in some environments. Thermincola potens strain JR was isolated from the anode of a microbial fuel cell inoculated with anaerobic digester sludge and operated at 55 °C. Preliminary characterization revealed that T. potens coupled acetate oxidation to the reduction of hydrous ferric oxides (HFO) or the humic substances analog, anthraquinone-2,6-disulfonate (AQDS). The genome of T. potens was recently sequenced, and the abundance of multiheme c-type cytochromes (MHCs) is unusual for a Gram-positive bacterium. We present evidence from trypsin shaving LC-MS/MS experiments and surface-enhanced Raman spectroscopy (SERS) that indicates the expression of a number of MHCs during T. potens growth on either HFO or AQDS and that several MHCs are localized to the cell wall or cell surface of T. potens. Furthermore, one of the MHCs can be extracted from cells with low pH or denaturants suggesting a loose association with the cell wall or cell surface. Electron microscopy does not reveal an S-layer, and the precipitation of silver metal on the cell surface is inhibited by cyanide, supporting the involvement of surface-localized redox-active heme proteins in dissimilatory metal reduction. These results are the first direct evidence for cell-wall associated cytochromes and MHC involvement in conducting electrons across the cell envelope of a Gram-positive bacterium.

Carlson, H. K.; Iavarone, A. T.; Gorur, A.; Yeo, B. S.; Tran, R.; Melnyk, R. A.; Mathies, R. A.; Auer, M.; Coates, J. D.

2011-12-01

361

Role of Encapsulation in the Pathogenesis of Anaerobic Gram-Positive Cocci.  

National Technical Information Service (NTIS)

The pathogenicity of 22 anaerobic and facultative Gram-positive cocci (AFGPC) was investigated by inoculating then into mice and determining their ability to cause subcutaneous abscesses. Only 11 heavily encapsulated isolates (> 50% of the cells were enca...

I. Brook R. I. Walker

1985-01-01

362

Cystic neutrophilic granulomatous mastitis: an underappreciated pattern strongly associated with gram-positive bacilli.  

PubMed

Although granulomatous lobular mastitis is associated with gram-positive bacilli such as Corynebacterium, this association is not well known. We report 3 cases of mastitis caused by gram-positive bacilli. All 3 abscesses were suppurative with distinct enlarged cystic spaces in which rare gram-positive bacilli were identified. Two cases were also granulomatous. Cultures in all 3 cases were negative. All 3 patients recovered after biopsy and tetracycline-based therapy. Infection in the breast by gram-positive bacilli is associated with a distinct histologic pattern, including cystic spaces in the setting of neutrophilic/granulomatous inflammation that can be recognized and should prompt careful search for the organism within enlarged vacuoles. PMID:21846918

Renshaw, Andrew A; Derhagopian, Robert P; Gould, Edwin W

2011-09-01

363

Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation  

PubMed Central

Background Thymoquinone is an active principle of Nigella sativa seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections. Methods The antibacterial activity of Thymoquinone (TQ) and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV) and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. Results TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 ?g/ml) especially Gram positive cocci (Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis CIP 106510). Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50) was reached with 22 and 60 ?g/ml for Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface. Conclusion The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential.

2011-01-01

364

Antibacterial activity and bonding ability of an adhesive incorporating an antibacterial monomer DMAE-CB.  

PubMed

This study evaluated the antibacterial effect and microtensile bond strength of a resin-based adhesive containing an antibacterial monomer DMAE-CB (methacryloxylethyl cetyl dimethyl ammonium chloride). Cured specimens of 1, 2, and 3% DMAE-CB-containing Single Bond 2 (crosslinking monomer: Bis-GMA, dimethacrylates; functional monomer: HEMA) were prepared, and their antibacterial effects on Streptococcus mutans ATCC 25175 were investigated. Antibacterial property after 0, 30, 90, and 180 days of aging was also tested. Bonding ability of the experimental adhesive incorporating 3% DMAE-CB was evaluated by microtensile bond strength test. The cured experimental adhesive exhibited an inhibitory effect on S. mutans growth, and the adhesive containing 3% DMAE-CB showed higher antibacterial efficiency compared with those incorporating 1 or 2% anibacterial monomer. Antibacterial activities of the specimens lasted for at least 180 days. Microtensile bond strength test revealed that the bonding ability of the experimental adhesive was not significantly adversely affected by the incorporation of DMAE-CB. Therefore, dental adhesives with strong and long-lasting bacteriostatic property could be achieved by incorporating DMAE-CB without negatively influencing bonding ability. PMID:19280645

Xiao, Yu-Hong; Ma, Sai; Chen, Ji-Hua; Chai, Zhi-Guo; Li, Fang; Wang, Ying-Jie

2009-08-01

365

Ligand effects on the structural dimensionality and antibacterial activities of silver-based coordination polymers.  

PubMed

Four Ag-based coordination polymers [Ag(Bim)] (1), [Ag2(NIPH)(HBim)] (2), [Ag6(4-NPTA)(Bim)4] (3) and [Ag2(3-NPTA)(bipy)0.5(H2O)] (4) (HBim = 1H-benzimidazole, bipy = 4,4'-bipyridyl, H2NIPH = 5-nitroisophthalic acid, H2NPTA = 3-/4-nitrophthalic acid) have been synthesized by hydrothermal reaction of Ag(i) salts with N-/O-donor ligands. Single-crystal X-ray diffraction indicated that these coordination polymers constructed from mononuclear or polynuclear silver building blocks exhibit three typical structure features from 1-D to 3-D frameworks. These compounds favour a slow release of Ag(+) ions leading to excellent and long-term antimicrobial activities, which is distinguished by their different topological structures, towards both Gram-negative bacteria, Escherichia coli (E. coli) and Gram-positive bacteria, Staphylococcus aureus (S. aureus). In addition, these compounds show good thermal stability and light stability under UV-vis and visible light, which are important characteristics for their further application in antibacterial agents. PMID:24871812

Lu, Xinyi; Ye, Junwei; Sun, Yuan; Bogale, Raji Feyisa; Zhao, Limei; Tian, Peng; Ning, Guiling

2014-07-14

366

Synthesis, characterisation and antibacterial activity of PVA/TEOS/Ag-Np hybrid thin films.  

PubMed

Novel hybrid material thin films based on polyvinyl alcohol (PVA)/tetraethyl orthosilicate (TEOS) with embedded silver nanoparticles (AgNps) were synthesized using sol-gel method. Two different strategies for the synthesis of silver nanoparticles in PVA/TEOS matrix were applied based on reduction of the silver ions by thermal annealing of the films or by preliminary preparation of silver nanoparticles using PVA as a reducing agent. The successful incorporation of silver nanoparticles ranging from 5 to 7nm in PVA/TEOS matrix was confirmed by TEM and EDX analysis, UV-Vis spectroscopy and XRD analysis. The antibacterial activity of the synthesized hybrid materials against etalon strains of three different groups of bacteria -Staphylococcus aureus (gram-positive bacteria), Escherichia coli (gram-negative bacteria), Pseudomonas aeruginosa (non-ferment gram-negative bacteria) has been studied as they are commonly found in hospital environment. The hybrid materials showed a strong bactericidal effect against E. coli, S. aureus and P. aeruginosa and therefore have potential applications in biotechnology and biomedical science. PMID:20557895

Bryaskova, Rayna; Pencheva, Daniela; Kale, Girish M; Lad, Umesh; Kantardjiev, T

2010-09-01

367

A Comparative Genome Analysis Identifies Distinct Sorting Pathways in Gram-Positive Bacteria  

Microsoft Academic Search

Surface proteins in gram-positive bacteria are frequently required for virulence, and many are attached to the cell wall by sortase enzymes. Bacteria frequently encode more than one sortase enzyme and an even larger number of potential sortase substrates that possess an LPXTG-type cell wall sorting signal. In order to elucidate the sorting pathways present in gram-positive bacteria, we performed a

David Comfort; Robert T. Clubb

2004-01-01

368

Structural Domain Based Multiple Instance Learning for Predicting Gram-Positive Bacterial Protein Subcellular Localization  

Microsoft Academic Search

Until recently, far few researches have been reported on Gram-positive protein subcelluar location prediction. Novel computational method is highly needed to help biologist design experiment. In this paper, we are motivated to propose a novel machine learning model for predicting Gram-positive protein subcelluar localization, as an alternative to the existing models Gpos-PLoc when the required GO annotation information is unavailable.

Suyu Mei; Wang Fei

2009-01-01

369

Protection from Lethal Gram-positive Infection by Macrophage Scavenger Receptor-dependent Phagocytosis  

Microsoft Academic Search

Infections with gram-positive bacteria are a major cause of morbidity and mortality in humans. Opsonin-dependent phagocytosis plays a major role in protection against and recovery from gram-positive infections. Inborn and acquired defects in opsonin generation and\\/or recognition by phagocytes are associated with an increased susceptibility to bacterial infections. In contrast, the physiological significance of opsonin-independent phagocytosis is unknown. Type I

Christian A. Thomas; Yongmei Li; Tatsuhiko Kodama; Hiroshi Suzuki; Samuel C. Silverstein; Joseph El Khoury

370

Antibiotic-Resistant Gram-Positive Cocci: Implications for Surgical Practice  

Microsoft Academic Search

. Gram-positive infections are causing more serious infections than ever before in surgical patients, who are increasingly\\u000a aged, ill, and debilitated. Invasive procedures disrupt natural barriers to bacterial invasion, and indwelling catheters may\\u000a act as conduits for infection. The use of broad-spectrum antibiotics selects for the emergence of resistant pathogens. Potential\\u000a sites of nosocomial gram-positive infections include the urinary tract,

Philip S. Barie

1998-01-01

371

Synthesis and in vitro antibacterial activity of 7-(3-alkoxyimino-4-methyl-4-methylaminopiperidin-1-yl)-fluoroquinolone derivatives.  

PubMed

A series of novel 7-(3-alkoxyimino-4-methyl-4-methylaminopiperidin-1-yl)fluoroquinolone derivatives were designed, synthesized, and characterized by 1H-NMR, MS, and HRMS. These fluoroquinolones were evaluated for their in-vitro antibacterial activity against representative Gram-positive and Gram-negative strains. Generally, all of the target compounds have considerable antibacterial activity against the tested forty strains, and exhibit exceptional potency in inhibiting the growth of methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) ATCC33591 (MICs: 0.06 to 2 microg/mL). In particular, compounds 14, 19, 28, and 29 are fourfold more potent than ciprofloxacin against MSSA 08-49. Compounds 23, 26, and 27 are twofold more potent than ciprofloxacin against MRSA ATCC33591 and MSSA ATCC29213. In addition, compound 14 exhibits excellent activity (MIC: 0.06 microg/mL) against Acinetobactes calcoaceticus, which is two- to 16-fold more potent than the reference drugs gemifloxacin, levofloxacin, and ciprofloxacin. PMID:20186866

Zhang, Yi-Bin; Feng, Lian-Shun; You, Xue-Fu; Guo, Qiang; Guo, Hui-Yuan; Liu, Ming-Liang

2010-03-01

372

Synthesis, spectroscopic characterization, structural studies and antibacterial and antitumor activities of diorganotin complexes with 3-methoxysalicylaldehyde thiosemicarbazone  

NASA Astrophysics Data System (ADS)

Three organotin(IV) complexes, Ph2Sn(mstsc) (1), Me2Sn(mstsc) (2) and Bu2Sn(mstsc) (3), have been synthesized from reaction of R2SnCl2 (R = Ph, Me and Bu) with 3-methoxysalicylaldehyde thiosemicarbazone (H2mstsc). The synthesized complexes have been characterized by elemental analysis and FT-IR, 1H, 13C and 119Sn NMR spectroscopy. The structures of 2 and 3 have been also confirmed by X-ray crystallography. On the basis of spectral and structural data thiosemicarbazone acts as a tridentate dianionic ligand and coordinates to tin through phenolic oxygen, the azomethine nitrogen and thiolate sulfur atoms. The metal coordination geometry for 2 and 3 is described as distorted square pyramid and the crystal lattices are stabilized by intermolecular hydrogen bands. On the basis of 119Sn NMR data, coordination number of tin retains five in solution. The in vitro antibacterial activity of ligand and its complexes has been evaluated against one Gram-positive and three Gram-negative bacteria. Complex 2 exhibited good activity along with the standard antibacterial drugs. The in vitro cytotoxicities of the synthesized compounds against Jurkat cells were evaluated by the standard WST-1 assay. The activity decreases in the order 3 > 1 > 2 = H2mstsc.

Khandani, Marzieh; Sedaghat, Tahereh; Erfani, Nasrollah; Haghshenas, Mohammad Reza; Khavasi, Hamid Reza

2013-04-01

373

Chemical composition and antibacterial activity of the essential oils of Ferula vesceritensis Coss et Dur. leaves, endemic in Algeria  

PubMed Central

Background The biological importance of members of genus Ferula promoted us to investigate the leaves of Ferula vesceritensis Coss et Dur. (endemic plant) previously not investigated. This study presents the chemical composition and antibacterial activities of the hydrodistilled oils. Results Volatile components of the leaves of F. vesceritensis have been studied by gas chromatography–mass spectrometry to afford 23 compounds. The major components were found to be 5,9-tetradecadiyne (24.72%), germacrene D (24.51%), farnesene (8.57%), and ?-bisabolene (8.57%). The antimicrobial activities of the essential oils were evaluated by disk diffusion method and tested against Gram-positive and Gram-negative bacteria. The volatile oil showed a strong antibacterial activity against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia. Conclusions These results reinforce the previous studies showing that the genus Ferula is considered as a good source of essential oils. The results presented here can be considered as the first information on the antimicrobial properties of F. vesceritensis.

2012-01-01

374

In vitro antibacterial activity and interactions with beta-lactamases and penicillin-binding proteins of the new monocarbam antibiotic U-78608.  

PubMed Central

U-78608, a new monocarbam antibiotic, was evaluated for in vitro activity against 312 clinical isolates of aerobic and anaerobic bacteria and subjected to several in vitro biochemical tests characterizing its interactions with beta-lactamases and penicillin-binding proteins (PBPs). The antibacterial activity of the compound was compared directly with those of SQ 83,360 (pirazmonam) and aztreonam. U-78608, SQ 83,360, and aztreonam had generally poor activity against gram-positive aerobic bacteria and anaerobic bacteria. U-78608 demonstrated activity primarily against gram-negative aerobic bacteria, with potency generally comparable to that of SQ 83,360. U-78608 and SQ 83,360 were less active than aztreonam for some gram-negative species; however, both compounds were 8- to 64-fold more active than aztreonam against Acinetobacter species, Pseudomonas aeruginosa, and Pseudomonas maltophilia. All three compounds resisted inactivation by several different beta-lactamases from gram-positive and gram-negative bacteria. Neither U-78608 nor SQ 83,360 exhibited significant inhibition of these enzymes, while aztreonam inhibited beta-lactamases from P. aeurginosa and Klebsiella oxytoca. All three compounds exhibited strong affinity to PBP 3 of Escherichia coli and moderate to negligible affinity to the other E. coli PBPs; quantitative measurements indicated that U-78608 had greater PBP 3 affinity than either SQ 83,360 or aztreonam. Images

Zurenko, G E; Truesdell, S E; Yagi, B H; Mourey, R J; Laborde, A L

1990-01-01

375

Structure-activity relationship of carbacephalosporins and cephalosporins: antibacterial activity and interaction with the intestinal proton-dependent dipeptide transport carrier of Caco-2 cells.  

PubMed

An intestinal proton-dependent peptide transporter located on the lumenal surface of the enterocyte is responsible for the uptake of many orally absorbed beta-lactam antibiotics. Both cephalexin and loracarbef are transported by this mechanism into the human intestinal Caco-2 cell line. Forty-seven analogs of the carbacephalosporin loracarbef and the cephalosporin cephalexin were prepared to evaluate the structural features necessary for uptake by this transport carrier. Compounds were evaluated for their antibacterial activities and for their ability to inhibit 1 mM cephalexin uptake and, subsequently, uptake into Caco-2 cells. Three clinically evaluated orally absorbed carbacephems were taken up by Caco-2 cells, consistent with their excellent bioavailability in humans. Although the carrier preferred the L stereoisomer, these compounds lacked antibacterial activity and were hydrolyzed intracellularly in Caco-2 cells. Compounds modified at the 3 position of cephalexin and loracarbef with a cyclopropyl or a trifluoromethyl group inhibited cephalexin uptake. Analogs with lipophilic groups on the primary amine of the side chain inhibited cephalexin uptake, retained activity against gram-positive bacteria but lost activity against gram-negative bacteria. Substitution of the phenylglycl side chain with phenylacetyl side chains gave similar results. Compounds which lacked an aromatic ring in the side chain inhibited cephalexin uptake but lost all antibacterial activity. Thus, the phenylglycl side chain is not absolutely required for uptake. Different structural features are required for antibacterial activity and for being a substrate of the transporter. Competition studies with cephalexin indicate that human intestinal Caco-2 cells may be a useful model system for initially guiding structure-activity relationships for the rational design of new oral agents. PMID:9257735

Snyder, N J; Tabas, L B; Berry, D M; Duckworth, D C; Spry, D O; Dantzig, A H

1997-08-01

376

Antibacterial activity of some plant extracts used in folk medicine.  

PubMed

In the present work, selected plants were screened for their potential antibacterial activity. For evaluating antibacterial activity, both aqueous and organic solvent methanol was used. The plants screened were Ocimum sanctum, Jatropha gossypifolia, Boerhavia diffusa, Azadirachta indica, Solidago virgaurea, and Commelina benghalensis. The antibacterial activity was assessed against six bacterial strains--Pseudomonas testosteroni, Staphylococcus epidermidis, Klebsiella pneumoniae, Bacillus subtilis, Proteus morganii, Micrococcus flavus. Agar disc diffusion method and Agar ditch diffusion method were used to study the antibacterial activity of all these plants. Ps. testosteroni and K. pneumoniae were the most resistant bacterial strains. A. indica showed strong activity against tested bacterial strains. Therefore, we conclude that A. indica may prove to be a promising agent, and further exploration into this compound should be performed to determine its full therapeutic potential. In addition, its leaf extract can also be used as a lead molecule in combating the diseases caused by the studied bacterial strains. PMID:18928141

Nair, Rathish; Kalariya, Tamanna; Chanda, Sumitra

2007-01-01

377

Development of an Organ Culture System for the Study of an Invasive Gram Positive Organism Infecting Bullfrogs, 'Rana catesbeiana'.  

National Technical Information Service (NTIS)

Recent observations on frogs afflicted with red-leg disease indicate that the clinically important bacteria associated with this disease include 13 gram negative bacteria and one gram positive bacterium. Attempts to study the role of the gram positive iso...

R. L. Amborski J. C. Glorioso G. F. Amborski

1974-01-01

378

Assessment of phytochemical content, polyphenolic composition, antioxidant and antibacterial activities of Leguminosae medicinal plants in Peninsular Malaysia  

PubMed Central

Background Many medicinal plants from Leguminosae family can be found easily in Malaysia. These plants have been used as traditional medicines by local ethnic groups, where they are prepared as decoction, pastes for wound infections, and some have been eaten as salad. This paper focused on the assessment of antioxidant potential, antibacterial activity and classes of phytochemicals of nine plants from the Leguminosae family. Methods Acacia auriculiformis, Bauhinia kockiana, Bauhinia purpurea, Caesalpinia pulcherrima, Calliandra tergemina, Cassia surattensis, Leucaena leucocephala, Peltophorum pterocarpum, and Samanea saman were extracted with aqueous methanol and dichloromethane:methanol mixture to test for antioxidant and antibacterial activities. The Folin-Ciocalteu assay was conducted to quantify the total phenolic content and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to determine the free radical quenching capacity. Antibacterial activity was assessed using disc diffusion (Kirby-Bauer) assay. Screening for major classes of phytochemical was done using standard chemical tests. Results B. kockiana flowers and C. pulcherrima leaves contained high total phenolic content (TPC) and strong DPPH radical scavenging ability with TPC of 8280 ± 498 mg GAE/100 g, IC50 of 27.0 ± 5.0 ?g/mL and TPC of 5030 ± 602 mg GAE/100 g, IC50 of 50.0 ± 5.0 ?g/mL respectively. Positive correlation was observed between TPC and free radical scavenging ability. Most extracts showed antibacterial activity against Gram positive bacteria at 1 mg, while none showed activity against Gram negative bacteria at the same dose. All extracts (except Samanea saman flower) showed antibacterial activity against two strains of methicillin resistant Staphylococcus aureus (MRSA) with MID values ranging between 100 ?g/disc and 500 ?g/disc. Conclusion The potential source of antioxidant and antibacterial agents, especially for MRSA infection treatments were found in B. kockiana, C. pulcherrima, C. tergemina and P. pterocarpum. These preliminary results would be a guide in the selection of potential candidates for further pharmacological study and in search of new drug candidate in treating MRSA infections.

2011-01-01

379

Antibacterial activities of surface modified electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) fibrous membranes  

NASA Astrophysics Data System (ADS)

Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane, with its excellent chemical and mechanical properties, has good potential for broad applications. However, due to its hydrophobic nature, microbial colonization is commonly encountered. In this work, electrospun PVDF-HFP fibrous membranes were surface modified by poly(4-vinyl- N-alkylpyridinium bromide) to achieve antibacterial activities. The membranes were first subjected to plasma pretreatment followed by UV-induced surface graft copolymerization of 4-vinylpyridine (4VP) and quaternization of the grafted pyridine groups with hexylbromide. The chemical composition of the surface modified PVDF-HFP electrospun membranes was studied by X-ray photoelectron spectroscopy (XPS). The morphology and mechanical properties of pristine and surface modified PVDF-HFP fibrous membranes were characterized by scanning electron microscopy (SEM) and tensile test, respectively. The antibacterial activities of the modified electrospun PVDF-HFP fibrous membranes were assessed against Gram-positive Staphylococcus aureus ( S. aureus) and Gram-negative Escherichia coli ( E. coli). The results showed that the PVDF-HFP fibrous membranes modified with quaternized pyridinium groups are highly effective against both bacteria with killing efficiency as high as 99.9999%.

Yao, Chen; Li, Xinsong; Neoh, K. G.; Shi, Zhilong; Kang, E. T.

2009-01-01

380

Antibacterial and anti-inflammatory activities of mycelia of a medicinal mushroom from Taiwan, Taiwanofungus salmoneus (higher Basidiomycetes).  

PubMed

Taiwanofungus salmoneus (T.T. Chang et W.N. Chou) Sheng H. Wu et al. (shiang-shan-chih), is a medicinal fungus indigenous to Taiwan. The mycelium was prepared from submerged culture and its ethanolic and hot-water extracts were used to study its antibacterial and anti-inflammatory activities. Gram-positive species (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) and gram-negative species (Escherichia coli and Salmonella typhimurium) of bacteria were used. In addition to the inhibitory zone, minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) also were determined. The ethanolic extracts showed higher inhibitory and bactericidal activities (MIC and MBC: 6.25-12.50 mg/ml) than the hot-water extracts (MIC and MBC: 25-50 mg/mL). In the anti-inflammatory test, the extracts were tested on lipopolysaccharide-induced nitric oxide and tumor necrosis factor- ? production in RAW 264.7 cells. The values of the inhibition concentration at 50% of nitric oxide production were 18.2 and 14.2 ?g/mL for the hot-water and ethanolic extracts, respectively. The 50% inhibitory concentration values of tumor necrosis factor- ? production were 4.99 and 7.13 ?g/mL for the hot-water and ethanolic extracts, respectively. On the basis of the results obtained, the mycelia could be used as an antibacterial and anti-inflammatory supplement. PMID:23510283

Chiang, Shen-Shih; Wang, Li-Ting; Chen, Shin-Yu; Mau, Jeng-Leun

2013-01-01

381

Synthesis and anti-bacterial activity of Cu, Ag and Cu-Ag alloy nanoparticles: A green approach  

SciTech Connect

Research highlights: {yields} Synthesis of novel nanosized copper-silver alloys of different compositions. {yields} Completely green approach for synthesis of water soluble bimetallic nanoparticle. {yields} Interesting anti-bacterial activity of as synthesized metal and alloy nanoparticle. -- Abstract: Metallic and bimetallic nanoparticles of copper and silver in various proportions were prepared by microwave assisted chemical reduction in aqueous medium using the biopolymer, starch as a stabilizing agent. Ascorbic acid was used as the reducing agent. The silver and copper nanoparticles exhibited surface plasmon absorption resonance maxima (SPR) at 416 and 584 nm, respectively; while SPR for the Cu-Ag alloys appeared in between depending on the alloy composition. The SPR maxima for bimetallic nanoparticles changes linearly with increasing copper content in the alloy. Transmission electron micrograph (TEM) showed monodispersed particles in the range of 20 {+-} 5 nm size. Both silver and copper nanoparticles exhibited emission band at 485 and 645 nm, respectively. The starch-stabilized nanoparticles exhibited interesting antibacterial activity with both gram positive and gram negative bacteria at micromolar concentrations.

Valodkar, Mayur; Modi, Shefaly; Pal, Angshuman [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India)] [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India); Thakore, Sonal, E-mail: drsonalit@gmail.com [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India)] [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India)

2011-03-15

382

Preparation and characterization of Zn/Ce/SO42--doped titania nano-materials with antibacterial activity  

NASA Astrophysics Data System (ADS)

SO42--doped Zn/Ce/TiO2 nano-materials (Zn/Ce/SO42-/TiO2) were prepared by a sol-gel method. The structures of Zn/Ce/SO42-/TiO2 nano-materials were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron (PL) spectroscopy and Fourier transform infrared spectroscopy (FT-IR). Gram-negative Escherichia coli (ATCC25922) and Gram-positive Staphylococcus aureus (ATCC6538) as model organisms, antibacterial activities of nano-materials were tested using inhibition zone method and shaking flask method under visible light irradiation and in the dark. The results show that the materials crystal structure and elemental composition are changed after SO42- doped. Zn/Ce/SO42-/TiO2 exhibit predominant antibacterial activity in the dark and visible light irradiation. The action mechanism of Zn/Ce/SO42-/TiO2 is discussed.

Wang, Yuzheng; Xue, Xiangxin; Yang, He; Luan, Che

2014-02-01

383

Thermophilic Gram-Positive Biocatalysts for Biomass Conversion to Ethanol  

SciTech Connect

Production of energy from renewable sources is receiving increased attention due to the finite nature of fossil fuels and the environmental impact associated with the continued large scale use of fossil energy sources. Biomass, a CO2-neutral abundant resource, is an attractive alternate source of energy. Biomass-derived sugars, such as glucose, xylose, and other minor sugars, can be readily fermented to fuel ethanol and commodity chemicals. Extracellular cellulases produced by fungi are commercially developed for depolymerization of cellulose in biomass to glucose for fermentation by appropriate biocatalysts in a simultaneous saccharification and fermentation (SSF) process. Due to the differences in the optimum conditions for the activity of the fungal cellulases and the growth and fermentation characteristics of the current industrial biocatalysts, SSF of cellulose is envisioned at conditions that are not optimal for the fungal cellulase activity leading to higher than required cost of cellulase in SSF. We have isolated bacterial biocatalysts whose growth and fermentation requirements match the optimum conditions for commercial fungal cellulase activity (pH 5.0 and 50 deg. C). These isolates fermented both glucose and xylose, major components of cellulose and hemicellulose, respectively, to L(+)-lactic acid. Xylose was metabolized through the pentose-phosphate pathway by these organisms as evidenced by the fermentation profile and analysis of the fermentation products of 13C1-xylose by NMR. As expected for the metabolism of xylose by the pentose-phosphate pathway, 13C-lactate accounted for more than 90% of the total 13C-labeled products. All three strains fermented crystalline cellulose to lactic acid with the addition of fungal cellulase (Spezyme CE) (SSF) at an optimum of about 10 FPU/g cellulose. These isolates also fermented cellulose and sugar cane bagasse hemicellulose acid hydrolysate simultaneously. Based on fatty acid profile and 16S rRNA sequence, these isolates cluster with Bacillus coagulans although B. coagulans type strain, ATCC 7050, failed to utilize xylose as a carbon source. For successful production of ethanol from pyruvate, both pyruvate decarboxylase (PDC) and alcohol dehydrogenase (AHD) need to be produced at optimal levels in these biocatalysts. A plasmid containing the S. ventriculi pdc gene and the adh gene from geobacillus stearothermophilus was constructed using plasmid pWH1520 that was successfully used for expression of pdc in B. megaterium. The resulting portable ethanol (PET) plasmid, pJAM423, was transformed into B. megaterium. After xylose induction, a significant fraction of cell cytoplasm was composed of the S. ventriculi PDC and G. stearothermophilus ADH proteins. In preliminary experiments, the amount of ethanol produced by b. megaterium with plasmid pJAM423 was about twice (20 mM) of the bacterium without the plasmid. These results show that the PET operon is functional in B. megaterium but high level ethanol production needs further genetic and metabolic engineering. A genetic transfer system for the second generation biocatalysts needs to be developed for transferring the plasmid pJAM423 and its derivatives for engineering these organisms for ethanol production from biomass derived sugars and cellulose to ethanol. One of the new biocatalysts, strain P4-102B was found to be transformable with plasmids and the method for introducing plasmid pJAM423 into this strain and expression of the encoded DNA is being optimized. These new second generation biocatalysts have the potential to reduce the cost of SSF by minimizing the amount of fungal cellulases, a significant cost component in the use of biomass as a renewable resource for production of fuels and chemicals.

Shanmugam, K.T.; Ingram, L.O.; Maupin-Furlow, J.A.; Preston, J.F.; Aldrich, H.C.

2003-12-01

384

Structure-activity study of the antibacterial peptide fallaxin  

PubMed Central

Fallaxin is a 25-mer antibacterial peptide amide, which was recently isolated from the West Indian mountain chicken frog Leptodactylus fallax. Fallaxin has been shown to inhibit the growth of several Gram-negative bacteria including Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Here, we report a structure–activity study of fallaxin based on 65 analogs, including a complete alanine scan and a full set of N- and C-terminal truncated analogs. The fallaxin analogs were tested for hemolytic activity and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate resistant S. aureus, (VISA), methicillin-susceptible S. aureus (MSSA), E. coli, K. pneumoniae, and P. aeruginosa. We identified several analogs, which showed improved antibacterial activity compared to fallaxin. Our best candidate was FA12, which displayed MIC values of 3.12, 25, 25, and 50 ?M against E. coli, K. pneumoniae, MSSA, and VISA, respectively. Furthermore, we correlated the antibacterial activity with various structural parameters such as charge, hydrophobicity ?H?, mean hydrophobic moment ??H?, and ?-helicity. We were able to group the active and inactive analogs according to mean hydrophobicity ?H? and mean hydrophobic moment ??H?. Far-UV CD-spectroscopy experiments on fallaxin and several analogs in buffer, in TFE, and in membrane mimetic environments (small unilamellar vesicles) indicated that a coiled-coil conformation could be an important structural trait for antibacterial activity. This study provides data that support fallaxin analogs as promising lead structures in the development of new antibacterial agents.

Nielsen, Sandra L.; Frimodt-M?ller, Niels; Kragelund, Birthe B.; Hansen, Paul R.

2007-01-01

385

Synthesis, molecular docking and biological evaluation of metronidazole derivatives containing piperazine skeleton as potential antibacterial agents.  

PubMed

Metronidazole has a broad-spectrum antibacterial activity. Hereby a series of novel metronidazole derivatives were designed and synthesized based on nitroimidazole scaffold in order to find some more potent antibacterial drugs. For these compounds which were reported for the first time, their antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus were tested. These compounds showed good antibacterial activities against Gram-positive strains. Compound 4m represented the most potent antibacterial activity against S. aureus ATCC 25923 with MIC of 0.003 ?g/mL and it showed the most potent activity against S. aureus TyrRS with IC50 of 0.0024 ?M. Molecular docking of 4m into S. aureus tyrosyl-tRNA synthetase active site were also performed to determine the probable binding mode. PMID:24680059

Wang, She-Feng; Yin, Yong; Qiao, Fang; Wu, Xun; Sha, Shao; Zhang, Li; Zhu, Hai-Liang

2014-04-15

386

Proteolytically activated anti-bacterial hydrogel microspheres.  

PubMed

Hydrogels are finding increased clinical utility as advances continue to exploit their favorable material properties. Hydrogels can be adapted for many applications, including surface coatings and drug delivery. Anti-infectious surfaces and delivery systems that actively destroy invading organisms are alternative ways to exploit the favorable material properties offered by hydrogels. Sterilization techniques are commonly employed to ensure the materials are non-infectious upon placement, but sterilization is not absolute and infections are still expected. Natural, anti-bacterial proteins have been discovered which have the potential to act as anti-infectious agents; however, the proteins are toxic and need localized release to have therapeutic efficacy without toxicity. In these studies, we explore the use of the glutathione s-transferase (GST) to anchor the bactericidal peptide, melittin, to the surface of poly(ethylene glycol) diacrylate (PEGDA) hydrogel microspheres. We show that therapeutic levels of protein can be anchored to the surface of the microspheres using the GST anchor. We compared the therapeutic efficacy of recombinant melittin released from PEGDA microspheres to melittin. We found that, when released by an activating enzyme, thrombin, recombinant melittin efficiently inhibits growth of the pathogenic bacterium Streptococcus pyogenes as effectively as melittin created by solid phase peptide synthesis. We conclude that a GST protein anchor can be used to immobilize functional protein to PEGDA microspheres and the protein will remain immobilized under physiological conditions until the protein is enzymatically released. PMID:23816641

Buhrman, Jason S; Cook, Laura C; Rayahin, Jamie E; Federle, Michael J; Gemeinhart, Richard A

2013-11-10

387

Gas chromatography-mass spectroscopy analysis of bioactive petalostigma extracts: Toxicity, antibacterial and antiviral activities  

PubMed Central

Background: Petalostigma pubescens and Petalostigma triloculare were common components of pharmacopeia's of multiple Australian Aboriginal tribal groupings which traditionally inhabited the areas in which they grow. Among these groups, they had a myriad of medicinal uses in treating a wide variety of bacterial, fungal and viral infections. This study was undertaken to test P. pubescens and P. triloculare leaf and fruit extracts for the ability to inhibit bacterial and viral growth and thus validate Australian Aboriginal usage of these plants in treating bacterial and fungal diseases. Materials and Methods: P. pubescens, and P. triloculare leaves and fruit were extracted and tested for antimicrobial, antiviral activity and toxicity. The bioactive extracts were further examined by RP-HPLC and GC-MS to identify the component compounds. Results: The methanol, water and ethyl acetate leaf and fruit extracts of displayed potent antibacterial activity. The methanol and ethyl acetate extracts displayed the broadest specificity, inhibiting the growth of 10 of the 14 bacteria tested (71%) for the leaf extract and 9 of the 14 bacteria tested (64%) for the fruit extracts. The water extracts also had broad spectrum antibacterial activity, inhibiting the growth of 8 (57%) and 7 (50%) of the 14 bacteria tested, respectively. All antibacterial extracts were approximately equally effective against Gram-positive and Gram-negative bacteria, inhibiting the growth of 50-75% of the bacteria tested. The methanol, water and ethyl acetate extracts also displayed antiviral activity in the MS2 plaque reduction assay. The methanol and water extracts inhibited 26.6-49.0% and 85.4-97.2% of MS2 plaque formation, respectively, with the fruit extracts being more potent inhibitors. All ethyl acetate extracts inhibited 100% of MS2 plaque formation. All extracts were also non-toxic or of low toxicity. Analysis of these extracts by RP-HPLC showed that the P. triloculare ethyl acetate fruit extract was the least complex of the bioactive extracts. Subsequent analysis of this extract by GC-MS revealed that it contained 9 main compounds: acetic acid; 2,2-dimethoxybutane; 4-methyl-1,3-dioxane; decane; unadecane; 2-furanmethanol; 1,2-benzenediol; 1,2,3-benzenetriol; and benzoic acid. Conclusion: These studies validate Australian Aboriginal therapeutic usage of Petalostigma species and indicate their medicinal potential.

Kalt, F. R.; Cock, I. E.

2014-01-01

388

Antibacterial and antifungal activities of new pyrazolo[3,4- d]pyridazin derivatives  

Microsoft Academic Search

Several new pyrazolo[3,4-d]pyridazin derivatives were prepared by the reaction of two new 1H-pyrazole-3-carboxylic acids and various hydrazines. The compounds were tested for antimicrobial activities against Gram-negative, Gram-positive bacteria and fungi. The compounds named as 7e, f had the highest antimicrobial activities against Gram-negative, Gram-positive bacteria and fungi with minimum inhibitory concentrations in the range of 0.31 to<0.0024 mg ml–1 .

Esvet Akbas; Ismet Berber

2005-01-01

389

Dry and moist heat sterilisation cannot inactivate pyrogenicity of Gram positive microorganisms.  

PubMed

In the monocytic cell line Mono Mac 6 pyrogens induce interleukin-6 secretion dose dependently. The aim of this study is to examine the interleukin-6 inducing capacity of Gram positive Staphylococcus aureus and Bacillus subtilis endospores after moist and dry heat sterilisation. Moist heat sterilisation of B. subtilis endospores for 15 min at 121 degrees C and 134 degrees C can only reduce the interleukin-6 inducing capacity to 57% and 63%, respectively, compared to untreated. Moist heat sterilisation of S. aureus for 60 min at 121 degrees C and 134 degrees C does not reduce the interleukin-6 inducing capacity of S. aureus. On the contrary moist heat sterilisation at 134 degrees C for 10, 20 and 40 min significantly increases the interleukin-6 inducing capacity compared to untreated S. aureus. This is confirmed in the rabbit pyrogen test. Dry heat sterilisation of B. subtilis endospores at 220 degrees C for 45 min reduces the interleukin-6 inducing capacity to 2% compared to untreated endospores. Dry heat treatment of S. aureus at 220 degrees C for 30 min only reduces the activity to 55%. However, after 250 degrees C for 30 min or 220 degrees C for 6h there is no detectable activity of S. aureus. In conclusion, neither the interleukin-6 inducing activity nor the pyrogenicity of S. aureus and endospores of B. subtilis can be inactivated by the heat sterilisation procedures described by the European Pharmacopoeia. PMID:16125917

Moesby, Lise; Hansen, Erik W; Christensen, Jens D; Høyer, Catrine H; Juhl, Gitte L; Olsen, Helle B

2005-11-01

390

Novel Bacterial NAD+-Dependent DNA Ligase Inhibitors with Broad-Spectrum Activity and Antibacterial Efficacy In Vivo? †  

PubMed Central

DNA ligases are indispensable enzymes playing a critical role in DNA replication, recombination, and repair in all living organisms. Bacterial NAD+-dependent DNA ligase (LigA) was evaluated for its potential as a broad-spectrum antibacterial target. A novel class of substituted adenosine analogs was discovered by target-based high-throughput screening (HTS), and these compounds were optimized to render them more effective and selective inhibitors of LigA. The adenosine analogs inhibited the LigA activities of Escherichia coli, Haemophilus influenzae, Mycoplasma pneumoniae, Streptococcus pneumoniae, and Staphylococcus aureus, with inhibitory activities in the nanomolar range. They were selective for bacterial NAD+-dependent DNA ligases, showing no inhibitory activity against ATP-dependent human DNA ligase 1 or bacteriophage T4 ligase. Enzyme kinetic measurements demonstrated that the compounds bind competitively with NAD+. X-ray crystallography demonstrated that the adenosine analogs bind in the AMP-binding pocket of the LigA adenylation domain. Antibacterial activity was observed against pathogenic Gram-positive and atypical bacteria, such as S. aureus, S. pneumoniae, Streptococcus pyogenes, and M. pneumoniae, as well as against Gram-negative pathogens, such as H. influenzae and Moraxella catarrhalis. The mode of action was verified using recombinant strains with altered LigA expression, an Okazaki fragment accumulation assay, and the isolation of resistant strains with ligA mutations. In vivo efficacy was demonstrated in a murine S. aureus thigh infection model and a murine S. pneumoniae lung infection model. Treatment with the adenosine analogs reduced the bacterial burden (expressed in CFU) in the corresponding infected organ tissue as much as 1,000-fold, thus validating LigA as a target for antibacterial therapy.

Mills, Scott D.; Eakin, Ann E.; Buurman, Ed T.; Newman, Joseph V.; Gao, Ning; Huynh, Hoan; Johnson, Kenneth D.; Lahiri, Sushmita; Shapiro, Adam B.; Walkup, Grant K.; Yang, Wei; Stokes, Suzanne S.

2011-01-01

391

Transport Capabilities of Eleven Gram-positive Bacteria: Comparative Genomic Analyses  

PubMed Central

The genomes of eleven Gram-positive bacteria that are important for human health and the food industry, nine low G+C lactic acid bacteria and two high G+C Gram-positive organisms, were analyzed for their complement of genes encoding transport proteins. Thirteen to eighteen percent of their genes encode transport proteins, larger percentages than observed for most other bacteria. All of these bacteria possess channel proteins, some of which probably function to relieve osmotic stress. Amino acid uptake systems predominate over sugar and peptide cation symporters, and of the sugar uptake porters, those specific for oligosaccharides and glycosides often outnumber those for free sugars. About 10% of the total transport proteins are constituents of putative multidrug efflux pumps with Major Facilitator Superfamily (MFS)-type pumps (55%) being more prevalent than ATP-binding cassette (ABC)-type pumps (33%), which, however, usually greatly outnumber all other types. An exception to this generalization is Streptococcus thermophilus with 54% of its drug efflux pumps belonging to the ABC superfamily and 23% belonging each to the Multidrug/Oligosaccharide/Polysaccharide (MOP) superfamily and the MFS. These bacteria also display peptide efflux pumps that may function in intercellular signalling, and macromolecular efflux pumps, many of predictable specificities. Most of the bacteria analyzed have no pmf-coupled or transmembrane flow electron carriers. The one exception is Brevibacterium linens, which in addition to these carriers, also has transporters of several families not represented in the other ten bacteria examined. Comparisons with the genomes of organisms from other bacterial kingdoms revealed that lactic acid bacteria possess distinctive proportions of recognized transporter types (e.g., more porters specific for glycosides than reducing sugars). Some homologues of transporters identified had previously been identified only in Gram-negative bacteria or in eukaryotes. Our studies reveal unique characteristics of the lactic acid bacteria such as the universal presence of genes encoding mechanosensitive channels, competence systems and large numbers of sugar transporters of the phosphotransferase system. The analyses lead to important physiological predictions regarding the preferred signalling and metabolic activities of these industrially important bacteria.

Lorca, Graciela L.; Barabote, Ravi D.; Zlotopolski, Vladimir; Tran, Can; Winnen, Brit; Hvorup, Rikki N.; Stonestrom, Aaron J.; Nguyen, Elizabeth; Huang, Li-Wen; Kim, David S.; Saier, Milton H.

2007-01-01