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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 and mechanism of action of tick defensin against Gram-positive bacteria  

Microsoft Academic Search

Defensins are a major group of antimicrobial peptides and are found widely in vertebrates, invertebrates and plants. Invertebrate defensins have been identified from insects, scorpions, mussels and ticks. In this study, chemically synthesized tick defensin was used to further investigate the activity spectrum and mode of action of natural tick defensin. Synthetic tick defensin showed antibacterial activity against many Gram-positive

Yoshiro Nakajima; Jun Ishibashi; Fumiko Yukuhiro; Ai Asaoka; DeMar Taylor; Minoru Yamakawa

2003-01-01

3

In vitro and in vivo antibacterial activities of heteroaryl isothiazolones against resistant gram-positive pathogens.  

PubMed

The activities of several tricyclic heteroaryl isothiazolones (HITZs) against an assortment of gram-positive and gram-negative clinical isolates were assessed. These compounds target bacterial DNA replication and were found to possess broad-spectrum activities especially against gram-positive strains, including antibiotic-resistant staphylococci and streptococci. These included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-nonsusceptible staphylococci, and quinolone-resistant strains. The HITZs were more active than the comparator antimicrobials in most cases. For gram-negative bacteria, the tested compounds were less active against members of the family Enterobacteriaceae but showed exceptional potencies against Haemophilus influenzae, Moraxella catarrhalis, and Neisseria spp. Good activity against several anaerobes, as well as Legionella pneumophila and Mycoplasma pneumoniae, was also observed. Excellent bactericidal activity against staphylococci was observed in time-kill assays, with an approximately 3-log drop in the numbers of CFU/ml occurring after 4 h of exposure to compound. Postantibiotic effects (PAEs) of 2.0 and 1.7 h for methicillin-susceptible S. aureus and MRSA strains, respectively, were observed, and these were similar to those seen with moxifloxacin at 10x MIC. In vivo efficacy was demonstrated in murine infections by using sepsis and thigh infection models. The 50% protective doses were antibacterial agents. PMID:17242152

Pucci, Michael J; Cheng, Jijun; Podos, Steven D; Thoma, Christy L; Thanassi, Jane A; Buechter, Douglas D; Mushtaq, Gohar; Vigliotti, Gerald A; Bradbury, Barton J; Deshpande, Milind

2007-01-22

4

In Vitro and In Vivo Antibacterial Activities of Heteroaryl Isothiazolones against Resistant Gram-Positive Pathogens?  

PubMed Central

The activities of several tricyclic heteroaryl isothiazolones (HITZs) against an assortment of gram-positive and gram-negative clinical isolates were assessed. These compounds target bacterial DNA replication and were found to possess broad-spectrum activities especially against gram-positive strains, including antibiotic-resistant staphylococci and streptococci. These included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-nonsusceptible staphylococci, and quinolone-resistant strains. The HITZs were more active than the comparator antimicrobials in most cases. For gram-negative bacteria, the tested compounds were less active against members of the family Enterobacteriaceae but showed exceptional potencies against Haemophilus influenzae, Moraxella catarrhalis, and Neisseria spp. Good activity against several anaerobes, as well as Legionella pneumophila and Mycoplasma pneumoniae, was also observed. Excellent bactericidal activity against staphylococci was observed in time-kill assays, with an approximately 3-log drop in the numbers of CFU/ml occurring after 4 h of exposure to compound. Postantibiotic effects (PAEs) of 2.0 and 1.7 h for methicillin-susceptible S. aureus and MRSA strains, respectively, were observed, and these were similar to those seen with moxifloxacin at 10× MIC. In vivo efficacy was demonstrated in murine infections by using sepsis and thigh infection models. The 50% protective doses were ?1 mg/kg of body weight against S. aureus in the sepsis model, while decreases in the numbers of CFU per thigh equal to or greater than those detected in animals treated with a standard dose of vancomycin were seen in the animals with thigh infections. Pharmacokinetic analyses of treated mice indicated exposures similar to those to ciprofloxacin at equivalent dose levels. These promising initial data suggest further study on the use of the HITZs as antibacterial agents.

Pucci, Michael J.; Cheng, Jijun; Podos, Steven D.; Thoma, Christy L.; Thanassi, Jane A.; Buechter, Douglas D.; Mushtaq, Gohar; Vigliotti, Gerald A.; Bradbury, Barton J.; Deshpande, Milind

2007-01-01

5

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

6

In vitro antibacterial activities of PD 138312 and PD 140248, new fluoronaphthyridines with outstanding gram-positive potency.  

PubMed Central

PD 138312 and PD 140248 are new quinolones with high in vitro activities against a wide spectrum of bacterial species, notably including gram-positive isolates. The respective MICs (in micrograms per milliliter) of PD 138312 and PD 140248 capable of inhibiting > or = 90% of the strains were < or = 0.06 and < or = 0.06 for oxacillin-susceptible and -resistant staphylococci, streptococci (including Streptococcus pyogenes, S. agalactiae, S. pneumoniae, and viridans group streptococci), Haemophilus influenzae, Moraxella catarrhalis, and Neisseria gonorrhoeae; 0.125 and 0.03 for Legionella pneumophila; 0.25 and 0.125 for Listeria monocytogenes; 0.25 and 0.25 for Enterococcus faecalis; 0.5 and 0.06 for anaerobic gram-positive cocci; 0.5 and 0.25 for Acinetobacter spp.; 0.5 and 0.5 for members of the family Enterobacteriaceae (excluding Serratia marcescens); 2 and 0.5 for Bacteroides fragilis; 2 and 2 for Serratia marcescens and ciprofloxacin-resistant staphylococci; and 8 and 4 for Pseudomonas aeruginosa.

Huband, M D; Cohen, M A; Meservey, M A; Roland, G E; Yoder, S L; Dazer, M E; Domagala, J M

1993-01-01

7

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

NASA Astrophysics Data System (ADS)

Ag-doped nanocrystalline hydroxyapatite nanoparticles (Ag:HAp-NPs) (Ca10- x Ag x (PO4)6(OH)2, x Ag = 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 x Ag = 0.05, a = b = 9.443 Å, c = 6.875 Å for x Ag = 0.2, and a = b = 9.445 Å, c = 6.877 Å for x Ag = 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 ( x Ag = 0.05, 0.2, and 0.3). Antibacterial activity increased with the increase of x Ag in the samples. The Ag:HAp-NP concentration had little influence on the bacterial growth ( P. stuartii).

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Le Coustumer, Phillippe; Constantin, Liliana Violeta; Predoi, Daniela

2012-06-01

8

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

9

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

PubMed

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). PMID:22721352

Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Le Coustumer, Phillippe; Constantin, Liliana Violeta; Predoi, Daniela

2012-06-21

10

In vitro antibacterial activity of modithromycin, a novel 6,11-bridged bicyclolide, against respiratory pathogens, including macrolide-resistant Gram-positive cocci.  

PubMed

The in vitro activities of modithromycin against Gram-positive and -negative respiratory pathogens, including macrolide-resistant cocci with different resistance mechanisms, were compared with those of other macrolide and ketolide agents. MICs were determined by the broth microdilution method. All 595 test strains used in this study were isolated from Japanese medical facilities. The erm (ribosome methylase) and/or mef (efflux pump) gene, which correlated with resistance to erythromycin as well as clarithromycin and azithromycin, was found in 81.8%, 21.3%, and 23.2% of Streptococcus pneumoniae, Streptococcus pyogenes, and methicillin-susceptible Staphylococcus aureus (MSSA) strains, respectively. Modithromycin showed MIC(90)s of 0.125 ?g/ml against these three cocci, including macrolide-resistant strains. In particular, the MIC of modithromycin against ermB-carrying S. pyogenes was ? 32-fold lower than that of telithromycin. The activities of modithromycin as well as telithromycin were little affected by the presence of mefA or mefE in both streptococci. Against Gram-negative pathogens, modithromycin showed MIC(90)s of 0.5, 8, and 0.031 ?g/ml against Moraxella catarrhalis, Haemophilus influenzae, and Legionella spp., respectively. The MICs of modithromycin against M. catarrhalis and H. influenzae were higher than those of telithromycin and azithromycin. However, modithromycin showed the most potent anti-Legionella activity among the macrolide and ketolide agents tested. These results suggested that the bicyclolide agent modithromycin is a novel class of macrolides with improved antibacterial activity against Gram-positive cocci, including telithromycin-resistant streptococci and intracellular Gram-negative bacteria of the Legionella species. PMID:21220534

Sato, Takafumi; Tateda, Kazuhiro; Kimura, Soichiro; Iwata, Morihiro; Ishii, Yoshikazu; Yamaguchi, Keizo

2011-01-10

11

Enhancement of antibacterial activity of capped silver nanoparticles in combination with antibiotics, on model gram-negative and gram-positive bacteria.  

PubMed

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. PMID:23970844

Kora, Aruna Jyothi; Rastogi, Lori

2013-07-18

12

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

Microsoft Academic Search

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\\u000a antibacterial activity of LysAB2, the complete LysAB2 and two deletion derivatives were constructed, purified and characterized.\\u000a Zymographic assays showed that only the intact LysAB2

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

2011-01-01

13

Antibacterial activity of Lactobacillus acidophilus strains isolated from honey marketed in Malaysia against selected multiple antibiotic resistant (MAR) Gram-positive bacteria.  

PubMed

A total of 32 lactic acid bacteria (LAB) were isolated from 13 honey samples commercially marketed in Malaysia, 6 strains identified as Lactobacillus acidophilus by API CHL50. The isolates had antibacterial activities against multiple antibiotic resistant's Staphylococcus aureus (25 to 32 mm), Staphylococcus epidermis (14 to 22 mm) and Bacillus subtilis (12 to 19 mm) in the agar overlay method after 24 h incubation at 30 °C. The crude supernatant was heat stable at 90 °C and 121 °C for 1 h. Treatment with proteinase K and RNase II maintained the antimicrobial activity of all the supernatants except sample H006-A and H010-G. All the supernatants showed antimicrobial activities against target bacteria at pH 3 and pH 5 but not at pH 6 within 72 h incubation at 30 °C. S. aureus was not inhibited by sample H006-A isolated from Libyan honey and sample H008-D isolated from Malaysian honey at pH 5, compared to supernatants from other L. acidophilus isolates. The presence of different strains of L. acidophilus in honey obtained from different sources may contribute to the differences in the antimicrobial properties of honey. PMID:22757710

Aween, Mohamed Mustafa; Hassan, Zaiton; Muhialdin, Belal J; Eljamel, Yossra A; Al-Mabrok, Asma Saleh W; Lani, Mohd Nizam

2012-07-01

14

Comparative In Vitro Activities of the Novel Antibacterial Finafloxacin against Selected Gram-Positive and Gram-Negative Bacteria Tested in Mueller-Hinton Broth and Synthetic Urine?  

PubMed Central

Kill kinetics and MICs of finafloxacin and ciprofloxacin against 34 strains with defined resistance mechanisms grown in cation-adjusted Mueller-Hinton broth (CAMHB) at pH values of 7.2 and 5.8 and in synthetic urine at pH 5.8 were determined. In general, finafloxacin gained activity at low pH values in CAMHB and remained almost unchanged in artificial urine. Ciprofloxacin MICs increased and bactericidal activity decreased strain dependently in acidic CAMHB and particularly in artificial urine.

Dalhoff, Axel; Stubbings, Will; Schubert, Sabine

2011-01-01

15

Comparative in vitro activities of the novel antibacterial finafloxacin against selected Gram-positive and Gram-negative bacteria tested in Mueller-Hinton broth and synthetic urine.  

PubMed

Kill kinetics and MICs of finafloxacin and ciprofloxacin against 34 strains with defined resistance mechanisms grown in cation-adjusted Mueller-Hinton broth (CAMHB) at pH values of 7.2 and 5.8 and in synthetic urine at pH 5.8 were determined. In general, finafloxacin gained activity at low pH values in CAMHB and remained almost unchanged in artificial urine. Ciprofloxacin MICs increased and bactericidal activity decreased strain dependently in acidic CAMHB and particularly in artificial urine. PMID:21245444

Dalhoff, Axel; Stubbings, Will; Schubert, Sabine

2011-01-18

16

In Vitro and In Vivo Activities of PD 0305970 and PD 0326448, New Bacterial Gyrase\\/Topoisomerase Inhibitors with Potent Antibacterial Activities versus Multidrug-Resistant Gram-Positive and Fastidious Organism Groups  

Microsoft Academic Search

Received 23 October 2006\\/Returned for modification 21 November 2006\\/Accepted 11 January 2007 PD 0305970 and PD 0326448 are new bacterial gyrase and topoisomerase inhibitors (quinazoline-2,4-diones) that possess outstanding in vitro and in vivo activities against a wide spectrum of bacterial species including quinolone- and multidrug-resistant gram-positive and fastidious organism groups. The respective MICs (g\\/ml) for PD 0305970 capable of inhibiting

Michael D. Huband; Michael A. Cohen; Margaret Zurack; Debra L. Hanna; Laura A. Skerlos; Mark C. Sulavik; Glenn W. Gibson; Jeffrey W. Gage; Edmund Ellsworth; Michael A. Stier; Stephen J. Gracheck

2007-01-01

17

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

PubMed

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

Bedeni?, Branka; Budimir, Ana; Gveri?, Ana; Plecko, Vanda; Vranes, Jasmina; Bubonja-Sonje, Marina; Kaleni?, Smilja

18

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

19

In Vitro and In Vivo Activities of PD 0305970 and PD 0326448, New Bacterial Gyrase/Topoisomerase Inhibitors with Potent Antibacterial Activities versus Multidrug-Resistant Gram-Positive and Fastidious Organism Groups?  

PubMed Central

PD 0305970 and PD 0326448 are new bacterial gyrase and topoisomerase inhibitors (quinazoline-2,4-diones) that possess outstanding in vitro and in vivo activities against a wide spectrum of bacterial species including quinolone- and multidrug-resistant gram-positive and fastidious organism groups. The respective MICs (?g/ml) for PD 0305970 capable of inhibiting ?90% of bacterial strains tested ranged from 0.125 to 0.5 versus staphylococci, 0.03 to 0.06 versus streptococci, 0.25 to 2 versus enterococci, and 0.25 to 0.5 versus Moraxella catarrhalis, Haemophilus influenzae, Listeria monocytogenes, Legionella pneumophila, and Neisseria spp. PD 0326448 MIC90s were generally twofold higher versus these same organism groups. Comparative quinolone MIC90 values were 4- to 512-fold higher than those of PD 0305970. In testing for frequency of resistance, PD 0305970 and levofloxacin showed low levels of development of spontaneous resistant mutants versus both Staphylococcus aureus and Streptococcus pneumoniae. Unlike quinolones, which target primarily gyrA and parC, analysis of resistant mutants in S. pneumoniae indicates that the likely targets of PD 0305970 are gyrB and parE. PD 0305970 demonstrated rapid bactericidal activity by in vitro time-kill testing versus streptococci. This bactericidal activity carried over to in vivo testing, where PD 0305970 and PD 0326448 displayed outstanding Streptococcus pyogenes 50% protective doses (PD50s) (oral dosing) of 0.7 and 3.6 mg/kg, respectively (ciprofloxacin and levofloxacin PD50s were >100 and 17.7 mg/kg, respectively). PD 0305970 was also potent in a pneumococcal pneumonia mouse infection model (PD50 = 3.2 mg/kg) and was 22-fold more potent than levofloxacin.

Huband, Michael D.; Cohen, Michael A.; Zurack, Margaret; Hanna, Debra L.; Skerlos, Laura A.; Sulavik, Mark C.; Gibson, Glenn W.; Gage, Jeffrey W.; Ellsworth, Edmund; Stier, Michael A.; Gracheck, Stephen J.

2007-01-01

20

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

21

In vitro antimicrobial activity of GAR936 tested against antibiotic-resistant gram-positive blood stream infection isolates and strains producing extended-spectrum ?-lactamases  

Microsoft Academic Search

GAR-936, a new, semisynthetic glycylcycline, has shown good antibacterial activity against a wide range of clinically important Gram-positive and –negative aerobic bacteria including Streptococcus pneumoniae,Hemophilus influenzae,Moraxella catarrhalis,Neisseria gonorrhoeae, most Enterobacteriaceae, Staphylococcus aureus and Enterococcus spp. The purpose of this study was to determine the activity of GAR-936 against a range of Gram-positive and –negative bloodstream isolates including many strains producing

Douglas J Biedenbach; Mondell L Beach; Ronald N Jones

2001-01-01

22

Novel antibacterial agents for the treatment of serious Gram-positive infections  

Microsoft Academic Search

With the continuing development of clinical drug resistance among bacteria and the advent of resistance to the recently released agents quinupristin- dalfopristin and linezolid, the need for new, effective agents to treat multi- drug-resistant Gram-positive infections remains important. This review focuses on agents presently in clinical development for the treatment of serious multidrug-resistant staphylococcal, enterococcal and pneumococcal infections, including methicillin-resistant

Darren Abbanat; Mark Macielag; Karen Bush

2003-01-01

23

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

24

In Vitro Activity of RU 64004, a New Ketolide Antibiotic, against Gram-Positive Bacteria  

Microsoft Academic Search

The comparative in vitro activity of RU 64004 (also known as HMR 3004), a new ketolide antibiotic, was tested by agar dilution against approximately 500 gram-positive organisms, including multiply resistant enterococci, streptococci, and staphylococci. All streptococci were inhibited by <1 mg of RU 64004 per ml. The ketolide was more potent than other macrolides against erythromycin A-susceptible staphylococci and was

T. SCHULIN; C. B. WENNERSTEN; R. C. MOELLERING; G. M. ELIOPOULOS

1997-01-01

25

Design, synthesis, and characterization of novel tetrahydropyran-based bacterial topoisomerase inhibitors with potent anti-gram-positive activity.  

PubMed

There is an urgent need for new antibacterial drugs that are effective against infections caused by multidrug-resistant pathogens. Novel nonfluoroquinolone inhibitors of bacterial type II topoisomerases (DNA gyrase and topoisomerase IV) have the potential to become such drugs because they display potent antibacterial activity and exhibit no target-mediated cross-resistance with fluoroquinolones. Bacterial topoisomerase inhibitors that are built on a tetrahydropyran ring linked to a bicyclic aromatic moiety through a syn-diol linker show potent anti-Gram-positive activity, covering isolates with clinically relevant resistance phenotypes. For instance, analog 49c was found to be a dual DNA gyrase-topoisomerase IV inhibitor, with broad antibacterial activity and low propensity for spontaneous resistance development, but suffered from high hERG K(+) channel block. On the other hand, analog 49e displayed lower hERG K(+) channel block while retaining potent in vitro antibacterial activity and acceptable frequency for resistance development. Furthermore, analog 49e showed moderate clearance in rat and promising in vivo efficacy against Staphylococcus aureus in a murine infection model. PMID:23968485

Surivet, Jean-Philippe; Zumbrunn, Cornelia; Rueedi, Georg; Hubschwerlen, Christian; Bur, Daniel; Bruyère, Thierry; Locher, Hans; Ritz, Daniel; Keck, Wolfgang; Seiler, Peter; Kohl, Christopher; Gauvin, Jean-Christophe; Mirre, Azely; Kaegi, Verena; Dos Santos, Marina; Gaertner, Mika; Delers, Jonathan; Enderlin-Paput, Michel; Boehme, Maria

2013-09-11

26

Potency and Bactericidal Activity of Iclaprim against Recent Clinical Gram-Positive Isolates?  

PubMed Central

The in vitro activity of iclaprim, a novel diaminopyrimidine derivative, was evaluated against 5,937 recent gram-positive clinical isolates collected in the United States and Europe. Iclaprim demonstrated potent activity against Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]), beta-hemolytic Streptococcus spp., and Enterococcus faecalis strains tested. In addition, iclaprim exhibited bactericidal activity against all S. aureus strains tested, including MRSA.

Sader, Helio S.; Fritsche, Thomas R.; Jones, Ronald N.

2009-01-01

27

Potency and bactericidal activity of iclaprim against recent clinical gram-positive isolates.  

PubMed

The in vitro activity of iclaprim, a novel diaminopyrimidine derivative, was evaluated against 5,937 recent gram-positive clinical isolates collected in the United States and Europe. Iclaprim demonstrated potent activity against Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]), beta-hemolytic Streptococcus spp., and Enterococcus faecalis strains tested. In addition, iclaprim exhibited bactericidal activity against all S. aureus strains tested, including MRSA. PMID:19289528

Sader, Helio S; Fritsche, Thomas R; Jones, Ronald N

2009-03-16

28

In vitro Activity of Biapenem against Recent Gram-Negative and Gram-Positive Clinical Isolates  

Microsoft Academic Search

The in vitro activity of biapenem, a new carbapenem, against 535 clinical recent isolates was compared with those of other antibiotics. Biapenem showed broad-spectrum activity against gram-negative and gram-positive clinical isolates. The new carbapenem was more active than imipenem against members of the family Enterobacteriaceae with MIC90S ranging from 0.12 to 2 mg\\/l and from 0.25 to 4 mg\\/l, respectively.

Giovanni Bonfiglio; Giuseppa Maccarone; Maria Lina Mezzatesta; Angela Privitera; Vincenzo Carciotto; Maria Santagati; Stefania Stefani; Giuseppe Nicoletti

1997-01-01

29

In Vitro Activities of RWJ-54428 (MC02,479) against Multiresistant Gram-Positive Bacteria  

Microsoft Academic Search

RWJ-54428 (MC-02,479) is a new cephalosporin with a high level of activity against gram-positive bacteria. In a broth microdilution susceptibility test against methicillin-resistant Staphylococcus aureus (MRSA), RWJ- 54428 was as active as vancomycin, with an MIC at which 90% of isolates are inhibited (MIC90 )o f 2mg\\/ml. For coagulase-negative staphylococci, RWJ-54428 was 32 times more active than imipenem, with an

SUZANNE CHAMBERLAND; JOHANNE BLAIS; MONICA HOANG; CYNTHIA DINH; DYLAN COTTER; EMMETT BOND; CARLA GANNON; CRAIG PARK; FRANCOIS MALOUIN; MICHAEL N. DUDLEY

2001-01-01

30

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

31

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

32

In vitro activity of the tribactam GV104326 against gram-positive, gram-negative, and anaerobic bacteria.  

PubMed Central

GV104326 is the first member of a new class of antibiotics (tribactams) selected for development. It combines a particularly broad spectrum (including gram-negative and gram-positive aerobes and anaerobes) with high potency, resistance to beta-lactamases, and complete stability to dehydropeptidases. Comparative MICs were determined for GV104326 against 415 recent clinical isolates (including beta-lactamase producers), using representative antibacterial agents (imipenem, amoxicillin-clavulanic acid, cefpirome, ciprofloxacin, gentamicin, and erythromycin). GV104326 was particularly active against gram-positive bacteria; in general, its in vitro activity was equivalent to that of imipenem, equivalent to or better than that of amoxicillin-clavulanic acid, and superior to that of cefpirome, ciprofloxacin, and erythromycin. Against gram-negative bacteria, GV104326 possessed activity similar to that of imipenem and cefpirome against enterobacteria and Haemophilus spp. but its activity was superior to that of amoxicillin-clavulanic acid. GV104326 showed excellent antianaerobe activity. GV104326 was stable to all clinically relevant beta-lactamases and was rapidly lethal to susceptible bacteria. In Escherichia coli, GV104326 bound predominantly to PBPs 1a and 2 and at low concentrations osmotically stable round forms were observed. GV104326 showed an affinity for PBPs 2 and 4 of Staphylococcus aureus.

Di Modugno, E; Erbetti, I; Ferrari, L; Galassi, G; Hammond, S M; Xerri, L

1994-01-01

33

In Vitro Activities of Two Ketolides, HMR 3647 and HMR 3004, against Gram-Positive Bacteria  

Microsoft Academic Search

The in vitro activities of two new ketolides, HMR 3647 and HMR 3004, were tested by the agar dilution method against 280 strains of gram-positive bacteria with different antibiotic susceptibility profiles, including Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus spp. (group A streptococci, group B streptococci, Streptococcus pneumoniae, and alpha-hemolytic streptococci). Seventeen erythromycin- susceptible (Em s ), methicillin-susceptible S. aureus

KUMTHORN MALATHUM; TERESA M. COQUE; KAVINDRA V. SINGH; BARBARA E. MURRAY

1999-01-01

34

Comparative In Vitro Activities of Daptomycin and Vancomycin against Resistant Gram-Positive Pathogens  

Microsoft Academic Search

The in vitro activity of daptomycin against 224 current gram-positive clinical isolates including vancomycin- resistant Enterococcus faecium (VREF), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resis- tant Staphylococcus spp. (MRSS), and penicillin-resistant Streptococcus pneumoniae (PRSP) was evaluated. The MICs at which 90% of isolates are inhibited for daptomycin and vancomycin, respectively, were as follows: MRSA, 1 and 2 mg\\/ml; MRSS, 1 and 4

D. R. Snydman; N. V. Jacobus; L. A. McDermott; J. R. Lonks; J. M. Boyce

2000-01-01

35

InVitro Activities ofTwoGlycylcyclines against Gram-Positive Bacteria  

Microsoft Academic Search

derivatives of minocycline and6-demethyl-6-deoxytetracycline, respectively. Invitro activities of these twoantimicrobial agents werecompared withthose oftetracycline, minocycline, andseven other antimicrobial agents against 412 gram-positive organisms. Bothnewdrugs weresignificantly moreactive thanminocycline against methicillin- resistant Staphylococcus aureus (MICsfor90%o ofisolates tested, 0.25and0.5,ug\\/ml versus 4pg\\/ml). CL 329,998 inhibited allstreptococci, lactobacilli, andLeuconostoc spp. atconcentrations of<0.5,ug\\/ml, withCL 331,002 slightly lessactive against somespecies. Allenterococci, including minocycline-resistant and multidrug-resistant isolates, wereinhibited

G. M. ELIOPOULOS; C. B. WENNERSTEN; G. COLE; C. MOELLERING

1994-01-01

36

Activity of glycopeptides against vancomycin-resistant gram-positive bacteria.  

PubMed Central

Gram-positive bacteria resistant to vancomycin are rare; but they include members of the genera Leuconostoc, Lactobacillus, and Pediococcus, as well as recently emerging vancomycin-resistant strains of Enterococcus faecium and Enterococcus faecalis. Vancomycin, teicoplanin, and several vancomycin derivatives were tested for their activities against vancomycin-resistant gram-positive bacteria. Vancomycin-resistant E. faecium and E. faecalis were generally cross-resistant to other glycopeptides, but some N-substituted vancomycin derivatives were active against the resistant strains, with MICs of 2 to 32 micrograms/ml. These vancomycin derivatives also had significant levels of activity against intrinsically vancomycin-resistant organisms such as Leuconostoc sp. While vancomycin resistance in E. faecium and E. faecalis was inducible, resistance in members of the genera Leuconostoc, Lactobacillus, and Pediococcus appeared to be expressed constitutively. Antibody to a vancomycin-induced membrane protein found in membranes of resistant enterococci did not detect a cross-reacting protein in other vancomycin-resistant species.

Nicas, T I; Cole, C T; Preston, D A; Schabel, A A; Nagarajan, R

1989-01-01

37

In vitro and in vivo activities of a new quinolone, WIN 57273, possessing potent activity against gram-positive bacteria.  

PubMed Central

The antibacterial activity of a new 7-dimethylpyridinyl quinolone, WIN 57273, was assessed by using in vitro and in vivo models. Agar inclusion and broth dilution in vitro tests revealed broad-spectrum activity against gram-positive and selected gram-negative organisms, with the greatest potency observed against the staphylococci. The MIC for 90% of coagulase-positive strains tested (MIC90) was less than or equal to 0.002 micrograms/ml; for the coagulase-negative strains the MIC90 was 0.008 micrograms/ml. Against enterococci the MIC90 was 0.06 micrograms/ml, with comparable activity observed against group A and group B streptococci as well as against the pneumococci. In general, the MIC90s for the gram-negative bacteria were less than or equal to 1 micrograms/ml. Exceptions were Serratia marcescens (MIC90, 16 micrograms/ml), Citrobacter freundii (MIC90, 4 micrograms/ml), and Pseudomonas aeruginosa (MIC90, 8 micrograms/ml). The greatest potency was observed against Haemophilus spp. and Neisseria spp., with MIC90s of 0.06 and 0.016 micrograms/ml, respectively. Broad-spectrum activity was also observed against anaerobes, with MIC90s ranging from 0.125 to 0.5 micrograms/ml among the species tested. The in vivo efficacy was determined by using a murine model by calculating the 50% protective doses against a lethal bacterial infection caused by strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Listeria monocytogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The staphylocci were most susceptible, with 50% protective doses for all strains ranging from 0.1 to 0.7 mg/kg. With the exception of the Pseudomonas infection, which was refractory to treatment, animals that were part of the other infection models responded to less than 10 mg/kg. Equivalent activity was seen with the subcutaneous or the oral route of drug administration. WIN 57273 was significantly more potent than ciprofloxacin in treating gram-positive bacterial infections (2- to 20-fold) but was significantly less effective at treating gram-negative bacterial infections (30- to 300-fold).

Sedlock, D M; Dobson, R A; Deuel, D M; Lesher, G Y; Rake, J B

1990-01-01

38

In vitro and in vivo activities of a new quinolone, WIN 57273, possessing potent activity against gram-positive bacteria.  

PubMed

The antibacterial activity of a new 7-dimethylpyridinyl quinolone, WIN 57273, was assessed by using in vitro and in vivo models. Agar inclusion and broth dilution in vitro tests revealed broad-spectrum activity against gram-positive and selected gram-negative organisms, with the greatest potency observed against the staphylococci. The MIC for 90% of coagulase-positive strains tested (MIC90) was less than or equal to 0.002 micrograms/ml; for the coagulase-negative strains the MIC90 was 0.008 micrograms/ml. Against enterococci the MIC90 was 0.06 micrograms/ml, with comparable activity observed against group A and group B streptococci as well as against the pneumococci. In general, the MIC90s for the gram-negative bacteria were less than or equal to 1 micrograms/ml. Exceptions were Serratia marcescens (MIC90, 16 micrograms/ml), Citrobacter freundii (MIC90, 4 micrograms/ml), and Pseudomonas aeruginosa (MIC90, 8 micrograms/ml). The greatest potency was observed against Haemophilus spp. and Neisseria spp., with MIC90s of 0.06 and 0.016 micrograms/ml, respectively. Broad-spectrum activity was also observed against anaerobes, with MIC90s ranging from 0.125 to 0.5 micrograms/ml among the species tested. The in vivo efficacy was determined by using a murine model by calculating the 50% protective doses against a lethal bacterial infection caused by strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Listeria monocytogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The staphylocci were most susceptible, with 50% protective doses for all strains ranging from 0.1 to 0.7 mg/kg. With the exception of the Pseudomonas infection, which was refractory to treatment, animals that were part of the other infection models responded to less than 10 mg/kg. Equivalent activity was seen with the subcutaneous or the oral route of drug administration. WIN 57273 was significantly more potent than ciprofloxacin in treating gram-positive bacterial infections (2- to 20-fold) but was significantly less effective at treating gram-negative bacterial infections (30- to 300-fold). PMID:2344163

Sedlock, D M; Dobson, R A; Deuel, D M; Lesher, G Y; Rake, J B

1990-04-01

39

Proinflammatory activity of cell-wall constituents from gram-positive bacteria.  

PubMed

Innate immunity reacts to conserved bacterial molecules. The outermost lipopolysaccharide (LPS) of Gram-negative organisms is highly inflammatory. It activates responsive cells via specific CD14 and toll-like receptor-4 (TLR4) surface receptor and co-receptors. Gram-positive bacteria do not contain LPS, but carry surface teichoic acids, lipoteichoic acids and peptidoglycan instead. Among these, the thick peptidoglycan is the most conserved. It also triggers cytokine release via CD14, but uses the TLR2 co-receptor instead of TLR4 used by LPS. Moreover, whole peptidoglycan is 1000-fold less active than LPS in a weight-to-weight ratio. This suggests either that it is not important for inflammation, or that only part of it is reactive while the rest acts as ballast. Biochemical dissection of Staphylococcus aureus and Streptococcus pneumoniae cell walls indicates that the second assumption is correct. Long, soluble peptidoglycan chains (approximately 125 kDa) are poorly active. Hydrolysing these chains to their minimal unit (2 sugars and a stem peptide) completely abrogates inflammation. Enzymatic dissection of the pneumococcal wall generated a mixture of highly active fragments, constituted of trimeric stem peptides, and poorly active fragments, constituted of simple monomers and dimers or highly polymerized structures. Hence, the optimal constraint for activation might be 3 cross-linked stem peptides. The importance of structural constraint was demonstrated in additional studies. For example, replacing the first L-alanine in the stem peptide with a D-alanine totally abrogated inflammation in experimental meningitis. Likewise, modifying the D-alanine decorations of lipoteichoic acids with L-alanine, or deacylating them from their diacylglycerol lipid anchor also decreased the inflammatory response. Thus, although considered as a broad-spectrum pattern-recognizing system, innate immunity can detect very subtle differences in Gram-positive walls. This high specificity underlines the importance of using well-characterized microbial material in investigating the system. PMID:14620147

Moreillon, P; Majcherczyk, P A

2003-01-01

40

Mutactimycin E, a New Anthracycline Antibiotic with Gram-positive Activity  

Microsoft Academic Search

Resistance to currently available antibiotics has become a widely recognized crisis in the medical community. To address this, many companies and researchers are refocusing their attention towards natural products, which have an excellent track record of producing effective antibacterial drugs. The AMRI natural product library was screened for activity against multi-drug resistant Staphylococcus aureus (MDRSA). The active samples were counter

D Craig Hopp; John Rabenstein; Joshua Rhea; Chris Smith; Khadidja Romari; Midori Clarke; Linda Francis; Macarena Irigoyen; Dennis Milanowski; Michele Luche; Grant J Carr; Ulla Mocek

2008-01-01

41

Superantigens of Gram-positive bacteria: structure—function analyses and their implications for biological activity  

Microsoft Academic Search

Just as we thought that we know everything about superantigens, new molecular and structural studies indicate that we have only just begun to unravel the secrets of these fascinating molecules. Recent structure—function analysis of superantigens from Gram-positive bacteria, with emphasis on their interaction with major histocompatibility complex molecules, could help us decipher the role of superantigens in disease, identify host

Malak Kotb

1998-01-01

42

Structure–activity relationship of antibacterial chalcones  

Microsoft Academic Search

The antibacterial activity of 31 chalcones was tested against bacterial strains, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 25923. Some of the tested chalcones showed fair to significant activity against Gram-positive bacteria. By comparison of the results obtained, the antibacterial activity can be related to features such as the presence of

Hugo Pereira Ávila; Elza de Fátima Albino Smânia; Franco Delle Monache; Artur Smânia

2008-01-01

43

In Vitro Activities of Dalbavancin and Nine Comparator Agents against Anaerobic Gram-Positive Species and Corynebacteria  

PubMed Central

Dalbavancin is a novel semisynthetic glycopeptide with enhanced activity against gram-positive species. Its comparative in vitro activities and those of nine comparator agents, including daptomycin, vancomycin, linezolid, and quinupristin-dalfopristin, against 290 recent gram-positive clinical isolates strains, as determined by the NCCLS agar dilution method, were studied. The MICs of dalbavancin at which 90% of various isolates tested were inhibited were as follows: Actinomyces spp., 0.5 ?g/ml; Clostridium clostridioforme, 8 ?g/ml; C. difficile, 0.25 ?g/ml; C. innocuum, 0.25 ?g/ml; C. perfringens, 0.125 ?g/ml; C. ramosum, 1 ?g/ml; Eubacterium spp., 1 ?g/ml; Lactobacillus spp., >32 ?g/ml, Propionibacterium spp., 0.5 ?g/ml; and Peptostreptococcus spp., 0.25 ?g/ml. Dalbavancin was 1 to 3 dilutions more active than vancomycin against most strains. Dalbavancin exhibited excellent activity against gram-positive strains tested and warrants clinical evaluation.

Goldstein, Ellie J. C.; Citron, Diane M.; Merriam, C. Vreni; Warren, Yumi; Tyrrell, Kerin; Fernandez, Helen T.

2003-01-01

44

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

45

Bacteriocins of gram-positive bacteria.  

PubMed

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. PMID:7603408

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

1995-06-01

46

On the target of a novel class of antibiotics, oxazolidinones, active against multidrug-resistant Gram-positive bacteria  

Microsoft Academic Search

Oxazolidinones are a promising new class of synthetic antibiotics active against multidrug-resistant Gram-positive bacteria. To elucidate their mode of action, the effect of DuP 721 on individual steps of protein translation was studied. The drug does not interfere with translation initiation at the stage of mRNA binding or formation of 30S pre-initiation complexes. However, it inhibits the puromycin-mediated release of

Helena Burghardt; Karl-Ludwig Schimz; Matthias Müller

1998-01-01

47

Activity of linezolid against multi-resistant Gram-positive bacteria from diverse hospitals in the United Kingdom  

Microsoft Academic Search

The in vitro activity of linezolid, an oxazolidinone, was assessed against 374 Gram-positive cocci, with an emphasis on testing multi-resistant, epidemiologically unrelated isolates. MICs of linezolid for staphylococci, pneumococci and streptococci had a narrow range, from 0.5 to 2 mg\\/L, whereas MICs for enterococci were uniformly 4 mg\\/L. For all the species tested, the MICs of linezolid were unrelated to

Alan P. Johnson; Marina Warner; David M. Livermore

2000-01-01

48

Kinetics and Quantification of Antibacterial Effects of Beta-Lactams, Macrolides, and Quinolones against Gram-Positive and Gram-Negative RTI Pathogens  

Microsoft Academic Search

Traditionally, the in vitro activity of antibacterial agents is characterized by their minimal inhibitory concentrations. However, these endpoints are,\\u000a by nature, discrete and do not provide information on time-dependent killing of the bacteria during the incubation period.\\u000a Nevertheless, the pharmacodynamic characteristics of antibacterial agents are almost always defined by correlating a static\\u000a endpoint describing the antibacterial activity of an agent

K.-J. Schaper; S. Schubert; A. Dalhoff

2005-01-01

49

Antibacterial activity of polygodial.  

PubMed

Polygodial was found to possess moderate antibacterial activity against gram-positive bacteria including Bacillus subtilis, Staphylococcus aureus and gram-negative bacteria including Escherichia coli and Salmonella choleraesuis with minimum bactericidal concentrations (MBC) of 100 and 100 microg/mL (0.34 mm) and 100 and 50 microg/mL, respectively. The time kill curve study showed that polygodial was bactericidal against B. subtilis and S. choleraesuis. However, there was a difference in its bactericidal action against endospore-forming B. subtilis and food-borne S. choleraesuis. PMID:16372365

Kubo, Isao; Fujita, Ken-ichi; Lee, Sang Hwa; Ha, Tae Joung

2005-12-01

50

Discovery of RWJ-54428 (MC-02,479), a new cephalosporin active against resistant gram-positive bacteria.  

PubMed

The discovery of RWJ-54428 (MC-02,479), a new cephalosporin displaying promising activity against sensitive and resistant Gram-positive bacteria, is described. Progressive structural modification from the previously reported 3-phenylthiocephem MC-02,331 afforded an overall increase in potency against MRSA while retaining other key properties such as acceptable solubility and serum binding. Evaluation of the in vitro potency and in vivo efficacy of a series of closely related compounds resulted in selection of RWJ-54428 (MC-02,479) for further studies. PMID:11213288

Hecker, S J; Glinka, T W; Cho, A; Zhang, Z J; Price, M E; Chamberland, S; Griffith, D; Lee, V J

2000-11-01

51

CD66b overexpression and homotypic aggregation of human peripheral blood neutrophils after activation by a gram-positive stimulus.  

PubMed

Neutrophils represent the main component of innate immunity in the clearance of bacterial infections. To pass the tissue and to localize and reach the site of infection, the peripheral blood neutrophils have to pass through a complex receptor-mediated interaction with the endothelial layer. Under pathophysiological conditions, such as severe sepsis, this process is impaired and often characterized by neutrophil aggregation. In this study, we examined the impact of three different Staphylococcus aureus strains on the activation status of human peripheral blood neutrophils by coincubation of bacterial culture supernatant with whole blood. This complex interaction of a gram-positive stimulus with blood components leads to a special neutrophil activation phenotype, which is characterized by an overexpression of the cell-surface molecule CD66b. The process is accompanied by a strong increase of homotypic aggregates and seems to be initialized by a massive activation impulse caused by the interplay of plasma components. This maximum activation of neutrophils prior to the complex and highly regulated activation required for transmigration might play a key role in the neutrophil dysfunction in gram-positive sepsis. PMID:22319104

Schmidt, Thomas; Zündorf, Josef; Grüger, Thomas; Brandenburg, Kerstin; Reiners, Ana-Lena; Zinserling, Jörg; Schnitzler, Norbert

2012-02-08

52

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

2013-06-14

53

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

54

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

55

Production of a bacteriocin by a poultry derived Campylobacter jejuni isolate with antimicrobial activity against Clostridium perfringens and other Gram positive bacteria.  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have purified a bacteriocin peptide (termed CUV-3), produced by a poultry cecal isolate of Campylobacter jejuni (strain CUV-3) with inhibitory activity against Gram positive bacteria including Clostridium perfringens (38 strains), Staphylococcus aureus, Staphylococcus epidermidis and Listeria mon...

56

Activities of the semisynthetic glycopeptide LY191145 against vancomycin-resistant enterococci and other gram-positive bacteria.  

PubMed Central

LY191145 is the prototype of a series of compounds with activities against vancomycin-resistant enterococci derived by modification of the glycopeptide antibiotic LY264826. LY191145 had MICs for vancomycin- and teicoplanin-resistant enterococci of < or = 4 micrograms/ml for 50% of isolates and < or = 16 micrograms/ml for 90% of isolates. Its MICs for vancomycin-resistant, teicoplanin-susceptible enterococci were 1 to 8 micrograms/ml. LY191145 retains the potent activities of its parent compound against staphylococci and streptococci. In vivo studies in a mouse infection model confirmed these activities. This compound indicates the potential of semisynthetic glycopeptides as agents against antibiotic-resistant gram-positive bacteria.

Nicas, T I; Mullen, D L; Flokowitsch, J E; Preston, D A; Snyder, N J; Stratford, R E; Cooper, R D

1995-01-01

57

Antimicrobial activity of gatifloxacin tested against 1676 strains of ciprofloxacin-resistant Gram-positive cocci isolated from patient infections in North and South America  

Microsoft Academic Search

Gatifloxacin (formerly AM-115) is a new 8-methoxy fluoroquinolone with an expanded spectrum against Gram-positive cocci and some anaerobes. To assess this new agent’s activity, a collection of 1,676 Gram-positive cocci were selected for resistance to ciprofloxacin (?4 ?g\\/mL) and tested against gatifloxacin and 18 other compounds by reference broth microdilution methods. The strains (approximately 23,000 total isolates from the SENTRY

Ronald N Jones; Mondell L Beach; Michael A Pfaller; Gary V Doern

1998-01-01

58

Comparison of the immunostimulatory and proinflammatory activities of candidate Gram-positive endotoxins, lipoteichoic acid, peptidoglycan, and lipopeptides, in murine and human cells  

Microsoft Academic Search

The role of lipopolysaccharide (LPS) in the pathogenesis of Gram-negative septic shock is well established. The corresponding proinflammatory and immunostimulatory molecule(s) on the Gram-positive bacteria is less well understood, and its identification and characterization would be a key prerequisite in designing specific sequestrants of the Gram-positive endotoxin(s). We report in this paper the comparison of NF-?B-, cytokine- and chemokine-inducing activities

Matthew R. Kimbrell; Hemamali Warshakoon; Jens R. Cromer; Subbalakshmi Malladi; Jennifer D. Hood; Rajalakshmi Balakrishna; Tandace A. Scholdberg; Sunil A. David

2008-01-01

59

Synthesis and antibacterial activity evaluation of metronidazole–triazole conjugates  

Microsoft Academic Search

Synthesis and antibacterial activity of metronidazole–triazole conjugates are reported. Total 21 hybrid compounds have been synthesized with different substitution pattern on the triazole ring in order to study their influence on the antibacterial activity. These compounds demonstrated potent to weak antibacterial activity against Gram-positive, and Gram-negative bacteria. Six compounds have shown equal or better antibacterial activity against Gram-negative strains than

Beena; Nitin Kumar; Rajesh K. Rohilla; N. Roy; Diwan S. Rawat

2009-01-01

60

Rational design of peptides active against the gram positive bacteria Staphylococcus aureus.  

PubMed

In an attempt to increase the antimicrobial activity of the insect defensin from Anopheles gambiae, which is active against Staphylococcus aureus at low concentration, hybrid defensins were designed by combining conserved sequence regions and variable regions of insect defensins. Their activity against S. aureus strains sensitive and resistant to conventional antibiotics was evaluated, and the toxicity of the most active molecules was tested. The three-dimensional structure of Anopheles gambiae defensin and five hybrids were determined by NMR and molecular modelling. This strategy led to the design of two chimeric defensins with increased activity compared with the native molecule, but one of them appears to be toxic to mice at a rather low concentration. The structure of the CS alphabeta motif, which is a characteristic of insect defensin, is sensitive to sequence modifications, in particular in the N-terminal loop. The existence of the CS alphabeta is most probably a prerequisite for the stability and the activity of the molecule, but is not sufficient by itself since the hybrid displaying the best defined structure is not active against the tested strains. The analysis of the structure, in relation with the activity and the toxicity data, underlines the importance of turns and of the N-terminal loop. Residues located in the turns contributing to the preservation of positive electrostatic areas at the surface of the molecules seem particularly important for the activity of the molecule, while residues involved in the N-terminal loop are both involved in the modulation of the activity and the toxicity of the molecule. PMID:18214975

Landon, Céline; Barbault, Florent; Legrain, Michèle; Guenneugues, Marc; Vovelle, Françoise

2008-07-01

61

An antimicrobial modified silicone peritoneal catheter with activity against both Gram positive and Gram negative bacteria  

Microsoft Academic Search

Peritonitis, exit site and tunnel infections are serious complications of peritoneal dialysis (CAPD), which may lead to catheter loss, despite measures taken to reduce the infection rate. Catheters coated with antimicrobials have shown only short-term activity. We have developed a process for conferring broad-spectrum, long-duration antimicrobial activity on CAPD catheters while reducing the risk of resistance. Catheters were processed using

Roger Bayston; Leanne E. Fisher; Klaus Weber

2009-01-01

62

Antimicrobial activity of Enterococcus Faecium Fair-E 198 against gram-positive pathogens  

PubMed Central

ABSTRACT This study investigated the antimicrobial activity of Enterococcus faecium FAIR-E 198 against Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. Using the critical-dilution method, the bacteriocin produced by E. faecium FAIR-E 198 inhibited all L. monocytogenes strains evaluated (1,600 to 19,200 AU mL-1). However, none of the B. cereus and S. aureus strains investigated were inhibited. The maximum activity of this bacteriocin (800 AU mL-1) was observed in MRS broth, while the activity in milk was 100 AU mL-1. In the co-cultivation test in milk, B. cereus K1-B041 was reduced to below the detection limit (1.00 log CFU mL-1) after 48 h. E. faecium reduced the initial L. monocytogenes Scott A population by 1 log CFU mL-1 after 3 h at 35°C, However, the pathogen regained growth, reaching 3.68 log CFU mL-1 after 48 h. E. faecium did not influence the growth of S. aureus ATCC 27154 during the 48 h of co-cultivation, Therefore, it can be concluded that the effectiveness of the antimicrobial activity of E. faecium FAIR-E 198 is strictly related to the species and strain of the target microorganism and to the culture medium,

do Nascimento, Maristela da Silva; Moreno, Izildinha; Kuaye, Arnaldo Yoshiteru

2010-01-01

63

Sortase activity is controlled by a flexible lid in the pilus biogenesis mechanism of gram-positive pathogens.  

PubMed

Pili are surface-linked virulence factors that play key roles in infection establishment in a variety of pathogenic species. In Gram-positive pathogens, pilus formation requires the action of sortases, dedicated transpeptidases that covalently associate pilus building blocks. In Streptococcus pneumoniae, a major human pathogen, all genes required for pilus formation are harbored in a single pathogenicity islet which encodes three structural proteins (RrgA, RrgB, RrgC) and three sortases (SrtC-1, SrtC-2, SrtC-3). RrgB forms the backbone of the streptococcal pilus, to which minor pilins RrgA and RrgC are covalently associated. SrtC-1 is the main sortase involved in polymerization of the RrgB fiber and displays a lid which encapsulates the active site, a feature present in all pilus-related sortases. In this work, we show that catalysis by SrtC-1 proceeds through a catalytic triad constituted of His, Arg, and Cys and that lid instability affects protein fold and catalysis. In addition, we show by thermal shift analysis that lid flexibility can be stabilized by the addition of substrate-like peptides, a feature shared by other periplasmic transpeptidases. We also report the characterization of a trapped acyl-enzyme intermediate formed between SrtC-1 and RrgB. The presence of lid-encapsulated sortases in the pilus biogenesis systems in many Gram-positive pathogens points to a common mechanism of substrate recognition and catalysis that should be taken into consideration in the development of sortase inhibitors. PMID:19810750

Manzano, Clothilde; Izoré, Thierry; Job, Viviana; Di Guilmi, Anne Marie; Dessen, Andréa

2009-11-10

64

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

65

Comparative Activities of Clinafloxacin against Gram-Positive and -Negative Bacteria  

PubMed Central

Activities of clinafloxacin, ciprofloxacin, levofloxacin, sparfloxacin, trovafloxacin, piperacillin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, ceftazidime, and imipenem against 354 ciprofloxacin-susceptible and -intermediate-resistant organisms were tested by agar dilution. Clinafloxacin yielded the lowest quinolone MICs (?0.5 ?g/ml against ciprofloxacin-susceptible organisms and ?16.0 ?g/ml against ciprofloxacin-intermediate-resistant organisms) compared to those of levofloxacin, trovafloxacin, and sparfloxacin. Ceftazidime, piperacillin alone or combined with tazobactam, trimethoprim-sulfamethoxazole, and imipenem usually yielded higher MICs against ciprofloxacin-resistant strains.

Ednie, Lois M.; Jacobs, Michael R.; Appelbaum, Peter C.

1998-01-01

66

Comparative in vitro activity of gemifloxacin against gram-positive and gram-negative clinical isolates in Argentina.  

PubMed

The in vitro activity of gemifloxacin against 1,000 clinical isolates of 147 Streptococcus pneumoniae (115, penicilin susceptible; 26, intermediate penicillin-resistant and 6, penicillin-resistant), 127 Hemophilus influenzae (109, beta lactamasa non-producer; 18, beta lactamase producers), 95 Streptococcus pyogenes (6, azytromycin-resistant), 84 Moraxella catarrhalis (79, beta lactamase producers), 110 Staphilococcus aureus (89, methicillin-susceptible; 21, methicilin-resistant), 98 Eenterococcus faecalis and 339 Enterobacteriacea, (recovered from patients with respiratory tract infection; skin and soft tissue infection and urinary tract infection), was compared with the activities of four fluorquinolones and five other antimicrobial agents. Of the quinolones tested, gemifloxacin was the most potent against Streptococcus pneumoniae, including penicillin intermediate and resistant strains. Mic(90) values obtained for gemifloxacin, ciprofloxacin, ofloxacin, levofloxacin and trvafloxacin were 0.03, 2, 2, 1 and 0.25 mg/L respectively. Gemifloxacin was 16 fold more potent than ciprofloxacin against methicillin-susceptible Staphylococcus aureus and 32 fold more potent than ciprofloxacin against Streptococcus pyogenes. When tested against Hemophilus influenzae, Moraxella catarrhalis and Enterobacteriaceae, all the quinolones showed similar activity. Our results demonstrate that gemifloxacin has similar activity than the other quinolones tested against Gram-negative organisms and is considerably more potent against Gram-positive organisms. PMID:11576792

Lopez, H; Stepanik, D; Vilches, V; Scarano, S; Sarachian, B; Mikaelian, G; Finlay, J; Sucari, A

2001-08-01

67

Antibacterial activity of dipropofol and related compounds.  

PubMed

Phenolic compounds, in general, exhibit antioxidant and antibacterial activities. We studied antimicrobial activity of the phenolic antioxidants, propofol (2,6-diisopropylphenol), tocopherol, eugenol, butylated hydroxyanisole (BHA), and several of their dimer compounds. Dipropofol (dimer of 2,6-diisopropylphenol) showed strong antibacterial activity against gram-positive strains including methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococci (VRE), while propofol and other monomeric and dimeric phenols having methyl or tert-butyl groups showed no remarkable activity. The results indicated that the dimeric structure of 2,6-diisopropylphenol moiety may play an important role in the antibacterial activity. PMID:15930760

Ogata, Masahiro; Tutumimoto Sato, Kanae; Kunikane, Takao; Oka, Kentaro; Seki, Masako; Urano, Shiro; Hiramatsu, Keiichi; Endo, Toyoshige

2005-06-01

68

New polyenic antibiotics active against gram-positive and -negative bacteria. I. Isolation and purification of antibiotics produced by Gluconobacter sp. W-315.  

PubMed

A new antibiotic, tentatively named as AB-315, was isolated from the fermentation broth of Gluconobacter sp. W-315. The antibiotic consists of a mixture of chemically related compounds. These compounds showed similar profiles in UV absorbancy. The antibiotics were active against Gram-positive and -negative bacteria, slightly active against fungi but not against yeasts. PMID:6216233

Watanabe, T; Izaki, K; Takahashi, H

1982-09-01

69

Novel Antibiotics Targeting Respiratory ATP Synthesis in Gram-Positive Pathogenic Bacteria  

PubMed Central

Emergence of drug-resistant bacteria represents a high, unmet medical need, and discovery of new antibacterials acting on new bacterial targets is strongly needed. ATP synthase has been validated as an antibacterial target in Mycobacterium tuberculosis, where its activity can be specifically blocked by the diarylquinoline TMC207. However, potency of TMC207 is restricted to mycobacteria with little or no effect on the growth of other Gram-positive or Gram-negative bacteria. Here, we identify diarylquinolines with activity against key Gram-positive pathogens, significantly extending the antibacterial spectrum of the diarylquinoline class of drugs. These compounds inhibited growth of Staphylococcus aureus in planktonic state as well as in metabolically resting bacteria grown in a biofilm culture. Furthermore, time-kill experiments showed that the selected hits are rapidly bactericidal. Drug-resistant mutations were mapped to the ATP synthase enzyme, and biochemical analysis as well as drug-target interaction studies reveal ATP synthase as a target for these compounds. Moreover, knockdown of the ATP synthase expression strongly suppressed growth of S. aureus, revealing a crucial role of this target in bacterial growth and metabolism. Our data represent a proof of principle for using the diarylquinoline class of antibacterials in key Gram-positive pathogens. Our results suggest that broadening the antibacterial spectrum for this chemical class is possible without drifting off from the target. Development of the diarylquinolines class may represent a promising strategy for combating Gram-positive pathogens.

Balemans, Wendy; Vranckx, Luc; Lounis, Nacer; Pop, Ovidiu; Guillemont, Jerome; Vergauwen, Karen; Mol, Selena; Gilissen, Ron; Motte, Magali; Lancois, David; De Bolle, Miguel; Bonroy, Kristien; Lill, Holger; Andries, Koen

2012-01-01

70

Antibacterial, anthelmintic and anti-amoebic activity in South African medicinal plants  

Microsoft Academic Search

Hexane, ethanol and water extracts of plants used by South African traditional healers for treating stomach ailments were screened for antibacterial, anthelmintic and anti-amoebic activities. To evaluate antibacterial activity, the disc-diffusion assay was used against several Gram-positive and Gram-negative species. Minimal inhibitory concentration values were determined with a microdilution assay. Ethanolic extracts showed the greatest activity, and Gram-positive bacteria were

L. J. McGaw; A. K. Jäger; J. van Staden

2000-01-01

71

Role for intracellular platelet-activating factor in the circulatory failure in a model of gram-positive shock.  

PubMed Central

1. This study investigates the effects of two structurally different antagonists of platelet-activating factor (PAF), BN52021 and WEB2086, on the circulatory and renal failure elicited by lipoteichoic acid (LTA) from Staphylococcus aureus (an organism without endotoxin) in anaesthetized rats. 2. Administration of LTA (10 mg kg-1, i.v.) caused hypotension and vascular hyporeactivity to noradrenaline (1 microgram kg-1, i.v.) WEB2086 (5 mg kg-1, i.v., 20 min before and 150 min after LTA) inhibited the delayed fall in mean arterial blood pressure (at 300 min: 99 +/- 6 mmHg vs. 75 +/- 6 mmHg, P < 0.01) and prevented the decrease in pressor response to noradrenaline (at 300 min: 36 +/- 5 mmHg min vs. 17 +/- 5 mmHg min, P < 0.01). Surprisingly, BN52021 (20 mg kg-1, i.v., 20 min before and 150 min after LTA) neither prevented the hypotension (74 +/- 6 mmHg) nor the vascular hyporeactivity (21 +/- 5 mmHg min). However, BN52021 inhibited the hypotension to injections of PAF as well as the circulatory failure elicited by lipopolysaccharides (10 mg kg-1, i.v.). 3. LTA caused an increase in plasma concentration of creatinine from 39 +/- 5 microM (sham-operated) to 70 +/- 8 microM and urea from 4.7 +/- 0.1 to 13.1 +/- 1.6 mM. The renal failure elicited by LTA was significantly inhibited by WEB2086 (creatinine: 45 +/- 4 microM and urea: 5.7 +/- 0.7 mM), but not by BN52021. 4. The induction of nitric oxide synthase activity in lungs by LTA was attenuated by WEB2086 from 98 +/- 17 to 40 +/- 15 pmol L-citrulline 30 min-1 mg-1 protein (P < 0.01), but not by BN52021 (148 +/- 21 pmol L-citrulline 30 min-1 mg-1 protein). Similarly, WEB2086, but not BN52021, inhibited the increase in plasma nitrite concentration associated with the delayed circulatory failure caused by LTA. The release of tumour necrosis factor-alpha (TNF-alpha) after injection of LTA was not attenuated by WEB2086. 5. The induction of nitrite release by cultured macrophages activated with LTA (10 micrograms ml-1 for 24 h) was inhibited by 74 +/- 4% by WEB2086 (3 x 10(-4) M), but not by BN52021, indicating that only WEB2086 acts on intracellular PAF receptors. 6. Thus, the intracellular release of PAF contributes to the circulatory and renal failure and induction of nitric oxide synthase elicited by LTA in anaesthetized rats. The difference between the two structurally different PAF antagonists in our septic shock models using either LTA or lipopolysaccharide (LPS), shows the importance of models for Gram-positive sepsis in the elucidation of the pathophysiology of septic shock and for the evaluation of potential drugs.

De Kimpe, S. J.; Thiemermann, C.; Vane, J. R.

1995-01-01

72

Potentiation of antibiotic activity by EDTA-tromethamine against three clinically isolated Gram-positive resistant bacteria. An in vitro investigation  

Microsoft Academic Search

Thein vitro synergistic effects of combinations of EDTA-tromethamine and five antimicrobial agents (ampicillin, cephalexin, oxytetracycline, streptomycin and sulphadimethoxine) on three clinically isolated Gram-positive bacteria (Staphylococcus aureus, Staphylococcus hominis andStreptococcus faecium) were investigated. The bacteria had been isolated from three cases of canine otitis resistant to ß-lactam antibiotic therapy. The antimicrobial activity was evaluated by measuring the minimal inhibitory concentration for

A. M. Farca; P. Nebbia; G. Re

1994-01-01

73

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

74

Activity of Linezolid against 3,251 Strains of Uncommonly Isolated Gram-Positive Organisms: Report from the SENTRY Antimicrobial Surveillance Program?  

PubMed Central

Linezolid was tested against 32 species of uncommonly isolated gram-positive organisms (3,251 strains) by reference MIC methods and found to be highly active (MIC50 range, 0.25 to 2 ?g/ml; MIC90 range, 0.25 to 2 ?g/ml). Only one isolate (viridans group streptococcus; 0.03% of tested strains) was resistant to linezolid.

Jones, Ronald N.; Stilwell, Matthew G.; Hogan, Patricia A.; Sheehan, Daniel J.

2007-01-01

75

Isolation and Mode of Action of a Staphylococcin-like Substance Active Against Gram-positive and Gram-negative Bacteria  

Microsoft Academic Search

Screening of non-phage group I1 Staphylococcus aureus strains for antagonistic substances revealed one particular strain, S. aureus D91, to excrete a substance with a wide spectrum of activity; both Gram-positive and Gram-negative bacteria were susceptible. The staphylococ- cin-like substance D91 produced by this strain was partially purified by column chromato- graphy on Sephadex G-50, DEAE-cellulose, Phenyl Sepharose CL-4B and Sephadex

O. A. KADER; H.-G. SAHL; H. BRANDIS

1984-01-01

76

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

77

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

78

Antibacterial activity of South African plants used for medicinal purposes  

Microsoft Academic Search

Crude extracts from 21 South African medicinal plants, traditionally used for ailments of an infectious or septic nature, were screened for in vitro antibacterial activity using the agar diffusion and dilution methods. Almost all the activity exhibited was against Gram-positive bacteria, with 12 of the 21 plant species tested showing some activity against Bacillus subtilis. Only the Warburgia salutaris methanol

Tonia Rabe; Johannes van Staden

1997-01-01

79

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

80

Antibacterial and antifungal activity of Syzygium jambolanum seeds  

Microsoft Academic Search

The water and methanolic extracts of Syzygium jambolanum seeds were examined for antibacterial and antifungal activity in vitro using the disc diffusion method, minimum inhibitory concentration, minimum bactericidal concentration and minimum fungicidal concentration. Activity against gram positive bacteria (Bacillus subtilis, Staphylococcus aureus), gram negative bacteria (Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli) and fungal strains (Candida albicans, Cryptococcus

M Chandrasekaran; V Venkatesalu

2004-01-01

81

In Vitro Activities of LY333328 and Comparative Agents against Nosocomial Gram-Positive Pathogens Collected in a 1997 Global Surveillance Study  

PubMed Central

The in vitro activity of LY333328 was evaluated for 1,479 nosocomial gram-positive pathogens isolated in 12 countries during 1997. LY333328 MICs at which 90% of the isolates tested were inhibited for Enterococcus faecalis (n = 351), Enterococcus faecium (n = 100), Staphylococcus aureus (n = 593), coagulase-negative Staphylococcus species (n = 325), and Streptococcus pneumoniae (n = 110) were 1, 1, 2, 2, and 0.015 ?g/ml, respectively. LY333328 demonstrated potent activity against isolates of vancomycin-resistant enterococci, oxacillin-resistant staphylococci, and penicillin-resistant pneumococci.

Zeckel, Michael L.; Preston, David A.; Allen, Bradley S.

2000-01-01

82

Antibacterial activity of the streptomycetes isolated from marine soil sample  

Microsoft Academic Search

Streptomyces species are the source of 70% of known antibiotics and they live in the soil where they encounter antibiotics produced by competing microbes, including other actinomycetes. Antibacterial activity of streptomycetes isolated from muttukkad area in Tamil Nadu has been studied. A total of 50 streptomycetes were subjected to primary screening by cross streak method against Gram-positive (Staphylococcus aureus, S.epidermidis)

S. Usha Nandhini; M. Masilamani Selvam

2011-01-01

83

Monitoring for antibiotic resistance in enterococci consequent upon feeding growth promoters active against gram-positive bacteria.  

PubMed

Commercial chicken and pig farms, using different growth promoters, were monitored for enterococci resistant to a range of antibacterial agents. Due to inconsistent findings attributed to uncontrollable factors, chickens kept under experimental conditions were also studied. A total of 4216 isolates from all the surveys were examined. Resistant isolates were often encountered, even in control groups, suggesting complex population changes not necessarily solely connected with the influence of the growth promoters. It was concluded that comprehensive methods for differentiating strains are necessary to unravel this problem. PMID:3921723

Linton, A H; Hinton, M H; Al-Chalaby, Z A

1985-03-01

84

Comparison of the immunostimulatory and proinflammatory activities of candidate Gram-positive endotoxins, lipoteichoic acid, peptidoglycan, and lipopeptides, in murine and human cells.  

PubMed

The role of lipopolysaccharide (LPS) in the pathogenesis of Gram-negative septic shock is well established. The corresponding proinflammatory and immunostimulatory molecule(s) on the Gram-positive bacteria is less well understood, and its identification and characterization would be a key prerequisite in designing specific sequestrants of the Gram-positive endotoxin(s). We report in this paper the comparison of NF-kappaB-, cytokine- and chemokine-inducing activities of the TLR2 ligands, lipoteichoic acid (LTA), peptidoglycan (PGN), and lipopeptides, to LPS, a prototype TLR4 agonist, in murine macrophage cell-lines as well as in human blood. In murine cells, di- and triacyl liopopeptides are equipotent in their NF-kappaB inducing activity relative to LPS, but elicit much lower proinflammatory cytokines. However, both LPS and the lipopeptides potently induce the secretion of a pattern of chemokines that is suggestive of the engagement of a TLR4-independent TRIF pathway. In human blood, although the lipopeptides induce p38 MAP kinase phosphorylation and CD11b upregulation in granulocytes at ng/ml concentrations, they do not elicit proinflammatory cytokine production even at very high doses; LTA, however, activates neutrophils and induces cytokine secretion, although its potency is considerably lower than that of LPS, presumably due to its binding to plasma proteins. We conclude that, in human blood, the pattern of immunostimulation and proinflammatory mediator production elicited by LTA parallels that of LPS. PMID:18468694

Kimbrell, Matthew R; Warshakoon, Hemamali; Cromer, Jens R; Malladi, Subbalakshmi; Hood, Jennifer D; Balakrishna, Rajalakshmi; Scholdberg, Tandace A; David, Sunil A

2008-04-18

85

Spectrum of gram-positive bacteraemia and in vitro activities of daptomycin, linezolid and vancomycin against organisms isolated from cancer patients.  

PubMed

Gram-positive organisms are the predominant bacterial pathogens in cancer patients. A survey indicated that coagulase-negative staphylococci (CoNS) (29.5%), Staphylococcus aureus (18.0%), Enterococcus spp. (12.1%) and viridans group streptococci (VGS) (9.1%) are isolated most often. The rate of reduced susceptibility to vancomycin (minimum inhibitory concentration ?1.0 ?g/mL) was 100% for meticillin-susceptible S. aureus and 99% for meticillin-resistant S. aureus, and 100% for meticillin-susceptible CoNS and 98% for meticillin-resistant CoNS. More than 98% of these isolates were susceptible to daptomycin and linezolid. Daptomycin and linezolid had comparable in vitro activity to vancomycin against Bacillus spp., Corynebacterium spp., Rhodococcus spp., Micrococcus spp., Stomatococcus mucilaginosus and VGS. Both agents were active against the majority (95%) of vancomycin-resistant organisms, including vancomycin-resistant enterococci, Pediococcus spp. and Leuconostoc spp. These data suggest that daptomycin and linezolid have an adequate antimicrobial spectrum and potent in vitro activity against Gram-positive isolates from cancer patients and may be considered as alternatives to vancomycin for empirical or targeted therapy in this setting. PMID:23481658

Rolston, Kenneth V I; Kapadia, Mona; Tarrand, Jeffrey; Coyle, Elizabeth; Prince, Randall A

2013-03-06

86

Antibacterial activity of chitosans and chitosan oligomers with different molecular weights  

Microsoft Academic Search

Antibacterial activities of six chitosans and six chitosan oligomers with different molecular weights (Mws) were examined against four gram-negative (Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Vibrio parahaemolyticus) and seven gram-positive bacteria (Listeria monocytogenes, Bacillus megaterium, B. cereus, Staphylococcus aureus, Lactobacillus plantarum, L. brevis, and L. bulgaricus). Chitosans showed higher antibacterial activities than chitosan oligomers and markedly inhibited growth of

Hong Kyoon No; Na Young Park; Shin Ho Lee; Samuel P Meyers

2002-01-01

87

The Determination of Antibacterial and Antifungal Activities of Polygonum hydropiper (L.) Root Extract  

Microsoft Academic Search

A study was conducted to determine the antibacterial and antifungal activities of Polygonum hydropiper (L.) root extract on chloroform against both bacteria and fungi using the disc diffusion method. The extract showed significant antibacterial activities against four gram-positive (Bacillus subtilis, Bacillus megaterium, Stapphylococcus aureus and Enterobacter aerogenes) and four gram-negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Shigella sonnei) bacteria.

M. F. Hasan; Alam Khan; M. S. Hossain; M. Rahman

88

In Vitro Antibacterial Activity and Pharmacodynamics of New Quinolones  

Microsoft Academic Search

  \\u000a This synopsis of published literature summarises data on the in vitro antibacterial activity and pharmacodynamics of fluoroquinolones.\\u000a Data were compiled for ciprofloxacin, levofloxcin, moxifloxacin, gatifloxacin, grepafloxacin, gemifloxacin, trovafloxacin,\\u000a sitafloxacin and garenoxacin. All of these quinolones are almost equipotent against gram-negative bacteria but demonstrate\\u000a improved activity against gram-positive species. The new quinolones are uniformly active against gram-positive species except\\u000a Streptococcus

A. Dalhoff; F.-J. Schmitz

2003-01-01

89

Silver triflate catalyzed synthesis of 3-aminoalkylated indoles and evaluation of their antibacterial activities.  

PubMed

An efficient, one-pot synthesis was developed for 3-aminoalkylated indoles by three-component coupling reaction of aldehydes, N-methylanilines, and indoles using AgOTf as a catalyst. A series of twenty 3-aminoalkylated indoles was evaluated for their antibacterial activities against both Gram negative and Gram positive bacteria. Compounds 4b and 4r showed good antibacterial activity against both Gram positive and Gram negative strains. However, inversing the property of substituent (from 4r to 4q) resulted in the significant fall in the magnitude of antibacterial activity against Escherichia coli. PMID:22373086

Rao, Vagicherla Kameshwara; Rao, Madharam Sudershan; Jain, Navin; Panwar, Jitendra; Kumar, Anil

2011-09-27

90

Silver triflate catalyzed synthesis of 3-aminoalkylated indoles and evaluation of their antibacterial activities  

PubMed Central

An efficient, one-pot synthesis was developed for 3-aminoalkylated indoles by three-component coupling reaction of aldehydes, N-methylanilines, and indoles using AgOTf as a catalyst. A series of twenty 3-aminoalkylated indoles was evaluated for their antibacterial activities against both Gram negative and Gram positive bacteria. Compounds 4b and 4r showed good antibacterial activity against both Gram positive and Gram negative strains. However, inversing the property of substituent (from 4r to 4q) resulted in the significant fall in the magnitude of antibacterial activity against Escherichia coli.

2011-01-01

91

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

2013-08-20

92

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

PubMed

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. PMID:23650575

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

2012-01-31

93

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

PubMed Central

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 daptomycin MICs determined on Ca2+-supplemented (50 mg/liter) brucella agar plates were one- to fourfold lower than those determined in unsupplemented media. Daptomycin was highly active (MICs, ?2 ?g/ml) against many strains including 36 of 37 peptostreptococci, 37 of 48 isolates of the Eubacterium group, and all strains of Propionibacterium spp., Clostridium perfringens, Clostridium difficile, and other Clostridium spp. It was fourfold or greater more active than vancomycin against Clostridium innocuum and 16 of 34 strains of vancomycin-resistant lactobacilli. Three strains of C. difficile for which quinupristin-dalfopristin and linezolid MICs were >8 ?g/ml were inhibited by <1 ?g of daptomycin per ml. Daptomycin MICs were ?4 ?g/ml for most strains of Clostridium clostridioforme, Clostridium paraputrificum, Clostridium tertium, and Clostridium ramosum; the isolates were generally more resistant to other antimicrobials. Daptomycin was two- to fourfold less active against Actinomyces spp. than vancomycin, quinupristin-dalfopristin, or linezolid. Twenty-nine of 31 strains of Corynebacterium spp., including Corynebacterium jeikeium, Corynebacterium amycolatum, and Corynebacterium pseudodiphtheriticum, were inhibited by ?0.25 ?g of daptomycin per ml. For two strains of “Corynebacterium aquaticum,” 8 ?g of daptomycin per ml was required for inhibition. Daptomycin demonstrated very good activities against a broad range of gram-positive organisms including vancomycin-resistant C. innocuum and lactobacillus strains and quinupristin-dalfopristin- and linezolid-resistant C. difficile strains.

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

2003-01-01

94

In vitro activities of daptomycin, vancomycin, quinupristin- dalfopristin, linezolid, and five other antimicrobials against 307 gram-positive anaerobic and 31 Corynebacterium clinical isolates.  

PubMed

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 daptomycin MICs determined on Ca(2+)-supplemented (50 mg/liter) brucella agar plates were one- to fourfold lower than those determined in unsupplemented media. Daptomycin was highly active (MICs, active than vancomycin against Clostridium innocuum and 16 of 34 strains of vancomycin-resistant lactobacilli. Three strains of C. difficile for which quinupristin-dalfopristin and linezolid MICs were >8 microg/ml were inhibited by <1 microg of daptomycin per ml. Daptomycin MICs were >or=4 microg/ml for most strains of Clostridium clostridioforme, Clostridium paraputrificum, Clostridium tertium, and Clostridium ramosum; the isolates were generally more resistant to other antimicrobials. Daptomycin was two- to fourfold less active against Actinomyces spp. than vancomycin, quinupristin-dalfopristin, or linezolid. Twenty-nine of 31 strains of Corynebacterium spp., including Corynebacterium jeikeium, Corynebacterium amycolatum, and Corynebacterium pseudodiphtheriticum, were inhibited by activities against a broad range of gram-positive organisms including vancomycin-resistant C. innocuum and lactobacillus strains and quinupristin-dalfopristin- and linezolid-resistant C. difficile strains. PMID:12499210

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

2003-01-01

95

In vitro assessment of Ag2O nanoparticles toxicity against Gram-positive and Gram-negative bacteria.  

PubMed

In view of antibiotic resistance among pathogens, the present study is to address the toxicity of Ag2O nanoparticles against the Gram-positive and Gram-negative bacteria through in vitro assays. The preliminary screening by agar diffusion assay confirms the antibacterial activity of Ag2O nanoparticles against all the test bacteria. Comparative antibacterial activity of Ag2O nanoparticles and respective antibiotics reveals their broad range of activity and lower inhibitory dose against the used bacterial strains. Further, they can inhibit E. coli with an effective dose of 0.036 mg/ml within 1 h of exposure time as determined by luciferin based ATP assay. Moreover, the Ag2O nanoparticles exhibit higher antibacterial efficacy against Gram-negative bacteria than Gram-positive bacteria, as revealed by their MIC & MBC values. Therefore, Ag2O nanoparticles pave the way for a new generation of antibacterial agents against the emerging multidrug resistant pathogens. PMID:23518522

Negi, Harshita; Rathinavelu Saravanan, Palaniyandi; Agarwal, Tithi; Ghulam Haider Zaidi, Mohd; Goel, Reeta

2013-01-01

96

Elafin (elastase-specific inhibitor) has anti-microbial activity against Gram-positive and Gram-negative respiratory pathogens  

Microsoft Academic Search

Elafin (elastase-specific inhibitor) is a low molecular weight inhibitor of neutrophil elastase which is secreted in the lung. Using synthetic peptides corresponding to full-length elafin (H2N-1AVT.....95Q-OH), the NH2-terminal domain (H2N-1AVT.....50K-OH) and the COOH-terminal domain (H2N-51PGS.....95Q-OH), we demonstrate that elafin’s anti-elastase activity resides exclusively in the COOH-terminus. Several characteristics of elafin suggest potential anti-microbial activity. The anti-microbial activity of elafin, and

A. J. Simpson; A. I. Maxwell; J. R. W. Govan; C. Haslett; J.-M. Sallenave

1999-01-01

97

Activities of the Semisynthetic Glycopeptide LY191145 against Vancomycin-Resistant Enterococci and Other Gram-Positive Bacteria  

Microsoft Academic Search

LY191145 is the prototype of a series of compounds with activities against vancomycin-resistant enterococci derived by modification of the glycopeptide antibiotic LY264826. LY191145 had MICs for vancomycin- and teicoplanin-resistant enterococci of <4 mg\\/ml for 50% of isolates and <16 mg\\/ml for 90% of isolates. Its MICs for vancomycin-resistant, teicoplanin-susceptible enterococci were 1 to 8 mg\\/ml. LY191145 retains the potent activities

THALIA I. NICAS; DEBORAH L. MULLEN; JANE E. FLOKOWITSCH; DAVID A. PRESTON; NANCY J. SNYDER; ROBERT E. STRATFORD; ANDROBIN D. G. COOPER

1995-01-01

98

An antimicrobial modified silicone peritoneal catheter with activity against both Gram-positive and Gram-negative bacteria.  

PubMed

Peritonitis, exit site and tunnel infections are serious complications of peritoneal dialysis (CAPD), which may lead to catheter loss, despite measures taken to reduce the infection rate. Catheters coated with antimicrobials have shown only short-term activity. We have developed a process for conferring broad-spectrum, long-duration antimicrobial activity on CAPD catheters while reducing the risk of resistance. Catheters were processed using an impregnation method. Three agents were used: rifampicin, triclosan and trimethoprim. Tests included establishing the duration of activity before test bacteria became resistant, the ability to kill 100% of attached bacteria in a predetermined time (tK100), and ability to withstand multiple high-count challenges until failure in a flow model. Antimicrobial activity continued until it was stopped at 280 days and the agents prevented the emergence of resistant strains. tK100 results showed a >99.9% reduction of attached bacteria. The flow model showed no colonization when repeatedly challenged with high loads of meticillin-resistant Staphylococcus aureus or Escherichia coli for approximately 90 days. The antimicrobial catheter material showed prolonged activity against common CAPD pathogens and promises to reduce clinical CAPD infection. PMID:19289248

Bayston, Roger; Fisher, Leanne E; Weber, Klaus

2009-03-16

99

Preparation of active antibacterial LDPE surface through multistep physicochemical approach: I. Allylamine grafting, attachment of antibacterial agent and antibacterial activity assessment.  

PubMed

Low-density polyethylene (LDPE) samples were treated in air plasma discharge, coated by polyallyamine brush thought copolymeric grafting surface-from reaction and deposited four common antibacterial agents (benzalkonium chloride, bronopol, chlorhexidine and triclosan) to gain material with active antibacterial properties. Surface characteristics were evaluated by static contact angle measurement with surface energy evaluation ATR-FTIR, X-ray Photoelectron Spectroscopy (XPS) and SEM analysis. Inhibition zone on agar was used as in vitro test of antibacterial properties on two representative gram positive Staphylococcus aureus (S. aureus) and gram negative Escherichia coli (E. coli) strains. It was confirmed, that after grafting of polyallyamine, more antibacterial agent is immobilized on the surface. The highest increase of antibacterial activity was observed by the sample containing triclosan. Samples covered by bronopol did not show significant antibacterial activity. PMID:21816580

Bílek, František; K?ížová, Tá?a; Lehocký, Marián

2011-07-18

100

Comparative in vitro activity of gemifloxacin against gram-positive and gram-negative clinical isolates in Argentina  

Microsoft Academic Search

The in vitro activity of gemifloxacin against 1,000 clinical isolates of 147 Streptococcus pneumoniae (115, penicilin susceptible; 26, intermediate penicillin-resistant and 6, penicillin-resistant), 127 Hemophilus influenzae (109, ? lactamasa non-producer; 18, ? lactamase producers), 95 Streptococcus pyogenes (6, azytromycin-resistant), 84 Moraxella catarrhalis (79, ? lactamase producers), 110 Staphilococcus aureus (89, methicillin-susceptible; 21, methicilin-resistant), 98 Eenterococcus faecalis and 339 Enterobacteriacea, (recovered

H Lopez; D Stepanik; V Vilches; S Scarano; B Sarachian; G Mikaelian; J Finlay; A Sucari

2001-01-01

101

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

102

Site-specific mutagenesis and functional analysis of active sites of sulfur oxygenase reductase from Gram-positive moderate thermophile Sulfobacillus acidophilus TPY.  

PubMed

Sequence alignments revealed that the conserved motifs of SORSa which formed an independent branch between archaea and Gram-negative bacteria SORs according to the phylogenetic relationship were similar with the archaea and Gram-negative bacteria SORs. In order to investigate the active sites of SORSa, cysteines 31, 101 and 104 (C31, C101, C104), histidines 86 and 90 (H86 and H90) and glutamate 114 (E114) of SORSa were chosen as the target amino acid residues for site-specific mutagenesis. The wild type and six mutant SORs were expressed in E. coli BL21, purified and confirmed by SDS-PAGE and Western blotting analysis. Enzyme activity determination revealed that the active sites of SORSa were identical with the archaea and Gram-negative bacteria SORs reported. Replacement of any cysteine residues reduced SOR activity by 53-100%, while the mutants of H86A, H90A and E114A lost their enzyme activities largely, only remaining 20%, 19% and 32% activity of the wild type SOR respectively. This study will enrich our awareness for active sites of SOR in a Gram-positive bacterium. PMID:23726793

Zhang, Huijun; Guo, Wenbin; Xu, Changan; Zhou, Hongbo; Chen, Xinhua

2013-05-29

103

In Vitro Activities of the New Semisynthetic Glycopeptide Telavancin (TD-6424), Vancomycin, Daptomycin, Linezolid, and Four Comparator Agents against Anaerobic Gram-Positive Species and Corynebacterium spp.  

PubMed Central

Telavancin is a new semisynthetic glycopeptide anti-infective with multiple mechanisms of action, including inhibition of bacterial membrane phospholipid synthesis and inhibition of bacterial cell wall synthesis. We determined the in vitro activities of telavancin, vancomycin, daptomycin, linezolid, quinupristin-dalfopristin, imipenem, piperacillin-tazobactam, and ampicillin against 268 clinical isolates of anaerobic gram-positive organisms and 31 Corynebacterium strains using agar dilution methods according to National Committee for Clinical Laboratory Standards procedures. Plates with daptomycin were supplemented with Ca2+ to 50 mg/liter. The MICs at which 90% of isolates tested were inhibited (MIC90s) for telavancin and vancomycin were as follows: Actinomyces spp. (n = 45), 0.25 and 1 ?g/ml, respectively; Clostridium difficile (n = 14), 0.25 and 1 ?g/ml, respectively; Clostridium ramosum (n = 16), 1 and 4 ?g/ml, respectively; Clostridium innocuum (n = 15), 4 and 16 ?g/ml, respectively; Clostridium clostridioforme (n = 15), 8 and 1 ?g/ml, respectively; Eubacterium group (n = 33), 0.25 and 2 ?g/ml, respectively; Lactobacillus spp. (n = 26), 0.5 and 4 ?g/ml, respectively; Propionibacterium spp. (n = 34), 0.125 and 0.5 ?g/ml, respectively; Peptostreptococcus spp. (n = 52), 0.125 and 0.5 ?g/ml, respectively; and Corynebacterium spp. (n = 31), 0.03 and 0.5 ?g/ml, respectively. The activity of TD-6424 was similar to that of quinupristin-dalfopristin for most strains except C. clostridioforme and Lactobacillus casei, where quinupristin-dalfopristin was three- to fivefold more active. Daptomycin had decreased activity (MIC > 4 ?g/ml) against 14 strains of Actinomyces spp. and all C. ramosum, Eubacterium lentum, and Lactobacillus plantarum strains. Linezolid showed decreased activity (MIC > 4 ?g/ml) against C. ramosum, two strains of C. difficile, and 15 strains of Lactobacillus spp. Imipenem and piperacillin-tazobactam were active against >98% of strains. The MICs of ampicillin for eight Clostridium spp. and three strains of L. casei were >1 ?g/ml. The MIC90 of TD-6424 for all strains tested was ?2 ?g/ml. TD-6424 has potential for use against infections with gram-positive anaerobes and deserves further clinical evaluation.

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

2004-01-01

104

Antimicrobial activity of daptomycin tested against Gram-positive pathogens collected in Europe, Latin America, and selected countries in the Asia-Pacific Region (2011).  

PubMed

We report the results of the international daptomycin surveillance programs for Europe, Latin America, and selected Asia-Pacific nations. A total of 7948 consecutive Gram-positive organisms of clinical significance were collected in 2011 and susceptibility tested against daptomycin and various comparator agents by Clinical and Laboratory Standards Institute (Clinical and Laboratory Standards Institute. M07-A9. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard: ninth edition Wayne, PA: CLSI. 2012.; Cubicin Package Insert 2012. Cubist Pharmaceuticals, Inc, Lexington, MA. Available at http://www.cubicin.com/pdf/PrescribingInformation.pdf. Accessed January 1, 2012.) broth microdilution methods. The test medium was adjusted to contain physiological levels of calcium (50 mg/L) when testing daptomycin. Daptomycin exhibited potent activity against methicillin-susceptible and -resistant Staphylococcus aureus overall and for each region (MIC(50/90), 0.25-0.5/0.5 ?g/mL), with susceptibility rates at 100.0% in Latin America, Australia/New Zealand, and India, and at 99.9% in Europe. The daptomycin MIC(50/90) for coagulase-negative staphylococci was also at 0.25-0.5/0.5 ?g/mL, and only 1 isolate was considered nonsusceptible with a MIC value at 2 ?g/mL. Daptomycin was also highly active against Enterococcus faecalis (MIC(50/90), 1/1-2 ?g/mL) and E. faecium (MIC(50/90), 2/2 ?g/mL for both vancomycin-susceptible and -resistant isolates). All enterococcal isolates were susceptible to daptomycin (MIC, ?4 ?g/mL) and tigecycline. Susceptibility to linezolid for E. faecalis was at 100.0%, while for E. faecium regional susceptibility rates were at 100.0% except in Europe (99.0%). Viridans group streptococci (MIC(50/90), 0.25/1 ?g/mL) and ?-haemolytic streptococci (MIC(50/90), ?0.06/0.25 ?g/mL) continue to be very susceptible to daptomycin. In summary, the results of this investigation document the high potency and wide spectrum of daptomycin when tested against a large resistance-surveillance collection of Gram-positive pathogens and indicate that daptomycin nonsusceptibility remains rare among indicated species after many years of clinical use worldwide. PMID:23514757

Sader, Helio S; Flamm, Robert K; Jones, Ronald N

2013-04-01

105

Platelet-activating factor receptor and innate immunity: uptake of gram-positive bacterial cell wall into host cells and cell-specific pathophysiology.  

PubMed

The current model of innate immune recognition of Gram-positive bacteria suggests that the bacterial cell wall interacts with host recognition proteins such as TLRs and Nod proteins. We describe an additional recognition system mediated by the platelet-activating factor receptor (PAFr) and directed to the pathogen-associated molecular pattern phosphorylcholine that results in the uptake of bacterial components into host cells. Intravascular choline-containing cell walls bound to endothelial cells and caused rapid lethality in wild-type, Tlr2(-/-), and Nod2(-/-) mice but not in Pafr(-/-) mice. The cell wall exited the vasculature into the heart and brain, accumulating within endothelial cells, cardiomyocytes, and neurons in a PAFr-dependent way. Physiological consequences of the cell wall/PAFr interaction were cell specific, being noninflammatory in endothelial cells and neurons but causing a rapid loss of cardiomyocyte contractility that contributed to death. Thus, PAFr shepherds phosphorylcholine-containing bacterial components such as the cell wall into host cells from where the response ranges from quiescence to severe pathophysiology. PMID:17056547

Fillon, Sophie; Soulis, Konstantinos; Rajasekaran, Surender; Benedict-Hamilton, Heather; Radin, Jana N; Orihuela, Carlos J; El Kasmi, Karim C; Murti, Gopal; Kaushal, Deepak; Gaber, M Waleed; Weber, Joerg R; Murray, Peter J; Tuomanen, Elaine I

2006-11-01

106

Effect of CL 184,005, a platelet-activating factor antagonist in a murine model of Staphylococcus aureus-induced gram-positive sepsis.  

PubMed

Experiments using a murine model of heat-killed Staphylococcus aureus-induced gram-positive bacterial sepsis indicate that the lethal bacterial effects can be prevented if mice are pretreated with CL 184,005, a platelet-activating factor (PAF) antagonist. CL 184,005 was ineffective when administered after bacterial challenge. Plasma of mice pretreated with CL 184,005 contained significantly less tumor necrosis factor (TNF), suggesting that CL 184,005 interferes with TNF synthesis induced by S. aureus. Spleen-associated TNF protein was also decreased by pretreatment with CL 184,005. Although TNF levels were significantly decreased in mice treated with CL 184,005, interleukin-6 levels in serum were significantly increased. Athymic mice were also susceptible to the lethal effects of S. aureus, suggesting that T cells were not involved. When rats rendered hypotensive with S. aureus were treated with CL 184,005, their blood pressure was normalized. Mice treated with enterotoxin B were not protected if they were pretreated with CL 184,005; however, TNF levels in these mice were significantly lower, suggesting that mediators other than PAF and TNF may contribute to the lethal effects of enterotoxin. PMID:8277176

DeJoy, S Q; Jeyaseelan, R; Torley, L W; Pickett, W C; Wissner, A; Wick, M M; Oronsky, A L; Kerwar, S S

1994-01-01

107

Antimicrobial Activity of the Investigational Pleuromutilin Compound BC-3781 Tested against Gram-Positive Organisms Commonly Associated with Acute Bacterial Skin and Skin Structure Infections  

PubMed Central

BC-3781 is a novel semisynthetic pleuromutilin antimicrobial agent developed as an intravenous and oral therapy for acute bacterial skin and skin structure infections (ABSSSI) and respiratory tract infections (RTI). BC-3781 and comparator agents were tested by the broth microdilution method against 1,893 clinical Gram-positive organisms predominantly causing ABSSSI. BC-3781 exhibited potent activity against methicillin-resistant Staphylococcus aureus (MIC50/90, 0.12/0.25 ?g/ml), coagulase-negative staphylococci (MIC50/90, 0.06/0.12 ?g/ml), ?-hemolytic streptococci (MIC50/90, 0.03/0.06 ?g/ml), viridans group streptococci (MIC50/90, 0.12/0.5 ?g/ml), and Enterococcus faecium (including vancomycin-nonsusceptible strains) (MIC50/90, 0.12/2 ?g/ml). Compared with other antibiotics in use for the treatment of ABSSSI, BC-3781 displayed the lowest MICs and only a minimal potential for cross-resistance with other antimicrobial classes.

Biedenbach, Douglas J.; Paukner, Susanne; Ivezic-Schoenfeld, Zrinka; Jones, Ronald N.

2012-01-01

108

Rice dehydrin K-segments have in vitro antibacterial activity.  

PubMed

Dehydrins are groups of plant proteins that have been shown to response to various environmental stimuli such as dehydration, elevated salinity, and low temperature. However, their roles in plant defense against microbes have not been demonstrated. In an attempt to discover plant antimicrobial proteins, we have screened a rice cDNA library and isolated several cDNAs coding for dehydrins. Protein extracts from Escherichia coli expressing these cDNAs were tested for their activity against Gram-positive bacteria (Bacillus pumilus, B. subtilis, Staphylococcus aureus, and Sarcina lutea) and Gram-negative bacteria (Escherichia coli and Xanthomonas oryzae pv. oryzae). The results indicate that the crude protein extracts exhibited antibacterial activities against the Gram-positive bacteria. However, dehydrins purified by immunoaffinity chromatography were not active against the bacteria. To pinpoint the dehydrin peptides that were responsible for the bactericidal activity, we expressed DNA sequences coding for truncated dehydrins containing either K- or S-segment and found that K-segment peptides, and not S-segment, were responsible for the antibacterial activities against Gram-positive bacteria. Antibacterial assay with synthetic K-segments indicated that the peptides inhibited growth of B. pumilus with minimum inhibition concentration and minimum bactericidal concentration of 130 and 400 ?g/ml, respectively. PMID:21639844

Zhai, C; Lan, J; Wang, H; Li, L; Cheng, X; Liu, G

2011-06-01

109

In vitro antibacterial activity of some plant essential oils  

Microsoft Academic Search

BACKGROUND:: To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species. METHODS:: The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the

Seenivasan Prabuseenivasan; Manickkam Jayakumar; Savarimuthu Ignacimuthu

2006-01-01

110

Screening for fractions of Oxytropis falcata Bunge with antibacterial activity  

Microsoft Academic Search

Preliminary studies with the four extracts of Oxytropis falcate Bunge exhibited that the chloroform and ethyl acetate extracts showed stronger antibacterial activities against the nine tested Gram-positive and Gram-negative bacteria. The HPLC-scanned and bioassay-guided fractionation led to the isolation and identification of the main flavonoid compounds, i.e. rhamnocitrin, kaempferol, rhamnetin, 2?,4?-dihydroxychalcone and 2?,4?,?-trihydroxy-dihydrochalcon. Except 2?,4?,?-trihydroxy-dihydrochalcon, four other compounds had good

H. Jiang; J. R. Hu; W. Q. Zhan; X. Liu

2009-01-01

111

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

Microsoft Academic Search

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

Anjali Mandlik; Asis Das; Hung Ton-That

2008-01-01

112

Gram-Positive Anaerobic Cocci  

PubMed Central

Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of organisms defined by their morphological appearance and their inability to grow in the presence of oxygen; most clinical isolates are identified to species in the genus Peptostreptococcus. GPAC are part of the normal flora of all mucocutaneous surfaces and are often isolated from infections such as deep organ abscesses, obstetric and gynecological sepsis, and intraoral infections. They have been little studied for several reasons, which include an inadequate classification, difficulties with laboratory identification, and the mixed nature of the infections from which they are usually isolated. Nucleic acid studies indicate that the classification is in need of radical revision at the genus level. Several species of Peptostreptococcus have recently been described, but others still await formal recognition. Identification has been based on carbohydrate fermentation tests, but most GPAC are asaccharolytic and use the products of protein degradation for their metabolism; the introduction of commercially available preformed enzyme kits affords a physiologically more appropriate method of identification, which is simple and relatively rapid and can be used in routine diagnostic laboratories. Recent reports have documented the isolation in pure culture of several species, notably Peptostreptococcus magnus, from serious infections. Studies of P. magnus have elucidated several virulence factors which correlate with the site of infection, and reveal some similarities to Staphylococcus aureus. P. micros is a strongly proteolytic species; it is increasingly recognized as an important pathogen in intraoral infections, particularly periodontitis, and mixed anaerobic deep-organ abscesses. Comparison of antibiotic susceptibility patterns reveals major differences between species. Penicillins are the antibiotics of choice, although some strains of P. anaerobius show broad-spectrum ?-lactam resistance.

Murdoch, D. A.

1998-01-01

113

Antibacterial Activity and Mechanism of Action of a Novel Anilinouracil-Fluoroquinolone Hybrid Compound?  

PubMed Central

The anilinouracils (AUs) such as 6-(3-ethyl-4-methylanilino)uracil (EMAU) are a novel class of gram-positive, selective, bactericidal antibacterials which inhibit pol IIIC, the gram-positive-specific replicative DNA polymerase. We have linked various fluoroquinolones (FQs) to the N-3 position of EMAU to generate a variety of AU-FQ “hybrids” offering the potential for targeting two distinct steps in DNA replication. In this study, the properties of a hybrid, “251D,” were compared with those of representative AUs and FQs in a variety of in vitro assays, including pol IIIC and topoisomerase/gyrase enzyme assays, antibacterial, bactericidal, and mammalian cytotoxicity assays. Compound 251D potently inhibited pol IIIC and topoisomerase/gyrase, displayed gram-positive antibacterial potency at least 15 times that of the corresponding AU compound, and as expected, acted selectively on bacterial DNA synthesis. Compound 251D was active against a broad panel of antibiotic-resistant gram-positive pathogens as well as several gram-negative organisms and was also active against both AU- and FQ-resistant gram-positive organisms, demonstrating its capacity for attacking both of its potential targets in the bacterium. 251D also was bactericidal for gram-positive organisms and lacked toxicity in vitro. Although we obtained strains of Staphylococcus aureus resistant to the individual parent compounds, spontaneous resistance to 251D was not observed. We obtained 251D resistance in multiple-passage experiments, but resistance developed at a pace comparable to those for the parent compounds. This class of AU-FQ hybrids provides a promising new pharmacophore with an unusual dual mechanism of action and potent activity against antibiotic-sensitive and -resistant gram-positive pathogens.

Butler, Michelle M.; LaMarr, William A.; Foster, Kimberly A.; Barnes, Marjorie H.; Skow, Donna J.; Lyden, Patrick T.; Kustigian, Lauren M.; Zhi, Chengxin; Brown, Neal C.; Wright, George E.; Bowlin, Terry L.

2007-01-01

114

In vitro antibacterial activity of some plant essential oils  

PubMed Central

Background: To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species. Methods: The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the active essential oils were tested using two fold agar dilution method at concentrations ranging from 0.2 to 25.6 mg/ml. Results: Out of 21 essential oils tested, 19 oils showed antibacterial activity against one or more strains. Cinnamon, clove, geranium, lemon, lime, orange and rosemary oils exhibited significant inhibitory effect. Cinnamon oil showed promising inhibitory activity even at low concentration, whereas aniseed, eucalyptus and camphor oils were least active against the tested bacteria. In general, B. subtilis was the most susceptible. On the other hand, K. pneumoniae exhibited low degree of sensitivity. Conclusion: Majority of the oils showed antibacterial activity against the tested strains. However Cinnamon, clove and lime oils were found to be inhibiting both gram-positive and gram-negative bacteria. Cinnamon oil can be a good source of antibacterial agents.

Prabuseenivasan, Seenivasan; Jayakumar, Manickkam; Ignacimuthu, Savarimuthu

2006-01-01

115

Innate sensors for Gram-positive bacteria  

Microsoft Academic Search

More than half of invasive bacterial infections are Gram-positive in origin. This class of bacteria has neither endotoxins nor an outer membrane, yet it generates some of the most powerful inflammatory responses known in medicine. Some recent seminal studies go a long way toward settling the controversies that surround the process by which Gram-positive bacterial surfaces trigger the human immune

Joerg R Weber; Philippe Moreillon; Elaine I Tuomanen

2003-01-01

116

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

117

Correlation between Major Constituents and Antibacterial Activities of Some Plant Essential Oils against Some Pathogenic Bacteria  

Microsoft Academic Search

Five different plant essential oils (Satureja hortensis, Thymus sipyleus ssp. rosulans, Thymus haussknechtii, Origanum rotundifolium (cultured form) and Origanum acutidens (wild and cultured form)) and their two major constituents carvacarol and thymol were evaluated for antibacterial activity against food-borne Gram negative (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella enteritidis) and Gram positive bacteria (Bacillus subtilis, Streptococcus pyogenes and Enterococcus

Neslihan Dikbas; Recep Kotan; Fatih Dadasoglu; Kenan Karagöz; Ramazan Çakmakci

118

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

2013-07-06

119

Comparative In Vitro Activities of AC98-6446, a Novel Semisynthetic Glycopeptide Derivative of the Natural Product Mannopeptimycin  , and Other Antimicrobial Agents against Gram-Positive Clinical Isolates  

Microsoft Academic Search

AC98-6446 is a novel semisynthetic cyclic glycopeptide antibiotic related to the natural product mannopep- timycin (AC98-1). In the present study the activity of AC98-6446 was evaluated against a variety of recent clinical gram-positive pathogens including multiply resistant strains. AC98-6446 demonstrated similar potent activities against methicillin-susceptible and methicillin-resistant staphylococci and glycopeptide-intermediate staphylococcal isolates (MICs at which 90% of isolates are inhibited

Peter J. Petersen; T. Z. Wang; Russell G. Dushin; Patricia A. Bradford

2004-01-01

120

Antibacterial activities of erythromycins A, B, C, and D and some of their derivatives.  

PubMed Central

The MICs of erythromycins A, B, C, and D and some of their derivatives were determined against 21 gram-positive and 15 gram-negative microorganisms. Antibacterial activity was confined to gram-positive and very few gram-negative bacteria. Erythromycin B was somewhat less active than erythromycin A, and erythromycin C and D showed about half that activity or even less. Most other derivatives had negligible activity. Determination of potency by diffusion and turbidimetric assays were in line with MICs. The examination of the results of these assays, however, revealed that there are differences between the data of different laboratories, depending on the microorganisms and conditions used.

Kibwage, I O; Hoogmartens, J; Roets, E; Vanderhaeghe, H; Verbist, L; Dubost, M; Pascal, C; Petitjean, P; Levol, G

1985-01-01

121

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

2013-08-29

122

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

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). PMID:23877700

Goldstein, Ellie J C; Citron, Diane M; Tyrrell, Kerin L; Merriam, C Vreni

2013-07-22

123

Biaryl isoxazolinone antibacterial agents.  

PubMed

In an era of increasing resistance to classical antibacterial agents, the synthetic oxazolidinone series of antibiotics has attracted much interest. Zyvoxtrade mark was the first oxazolidinone to be approved for clinical use against infections caused by multi-drug resistant Gram-positive bacteria. In the course of studies directed toward the discovery of novel antibacterial agents, a new series of synthetic phenyl-isoxazolinone agents that displayed potent activity against Gram-positive bacterial strains was recently discovered at Bristol-Myers Squibb. Extensive investigation of various substitutions on the phenyl ring was then undertaken. We report here, the synthesis and antibacterial activity of a series of biaryl isoxazolinone compounds. PMID:15869878

Quesnelle, Claude A; Gill, Patrice; Roy, Stephan; Dodier, Marco; Marinier, Anne; Martel, Alain; Snyder, Lawrence B; D'Andrea, Stanley V; Bronson, Joanne J; Frosco, Marybeth; Beaulieu, Danielle; Warr, Glen A; Denbleyker, Ken L; Stickle, Terry M; Yang, Hyekyung; Chaniewski, Susan E; Ferraro, Cheryl A; Taylor, Dennis; Russell, John W; Santone, Kenneth S; Clarke, Junius; Drain, Rebecca L; Knipe, Jay O; Mosure, Kathleen; Barrett, John F

2005-06-01

124

Activation of the complement system generates antibacterial peptides  

PubMed Central

The complement system represents an evolutionary old and significant part of the innate immune system involved in protection against invading microorganisms. Here, we show that the anaphylatoxin C3a and its inactivated derivative C3a-desArg are antibacterial, demonstrating a previously unknown direct antimicrobial effect of complement activation. The C3a peptide, as well as functional epitopes in the sequence, efficiently killed the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and the Gram-positive Enterococcus faecalis. In mice, a C3a-derived peptide suppressed infection by Gram-positive Streptococcus pyogenes bacteria. Fluorescence and electron microscopy demonstrated that C3a binds to and induces breaks in bacterial membranes. C3a was also found to induce membrane leakage of liposomes. These findings provide an interesting link between the complement system and antimicrobial peptides, which are two important branches of innate immunity.

Nordahl, Emma Andersson; Rydengard, Victoria; Nyberg, Patrik; Nitsche, D. Patric; Morgelin, Matthias; Malmsten, Martin; Bjorck, Lars; Schmidtchen, Artur

2004-01-01

125

Screening of Ethanol, Petroleum Ether and Chloroform Extracts of Medicinal Plants, Lawsonia inermis L. and Mimosa pudica L. for Antibacterial Activity  

PubMed Central

Organic extracts (ethanol, petroleum ether and chloroform) of two medicinal plants Lawsonia inermis L. and Mimosa pudica L. were proven for antibacterial properties against 15 Gram-positive and Gram-negative human pathogenic bacteria. Among the three types of extracts tested, ethanol extract was found to possess maximum antibacterial activity. The diameter of the zone of inhibition of bacterial growth showed that Gram-negative bacteria are more sensitive than Gram-positive bacteria to plant extracts. Between the two plants species studied, Lawsonia inermis extract showed more antibacterial activity compared to Mimosa pudica extract.

Akter, A.; Neela, F. A.; Khan, M. S. I.; Islam, M. S.; Alam, M. F.

2010-01-01

126

Screening of Ethanol, Petroleum Ether and Chloroform Extracts of Medicinal Plants, Lawsonia inermis L. and Mimosa pudica L. for Antibacterial Activity.  

PubMed

Organic extracts (ethanol, petroleum ether and chloroform) of two medicinal plants Lawsonia inermis L. and Mimosa pudica L. were proven for antibacterial properties against 15 Gram-positive and Gram-negative human pathogenic bacteria. Among the three types of extracts tested, ethanol extract was found to possess maximum antibacterial activity. The diameter of the zone of inhibition of bacterial growth showed that Gram-negative bacteria are more sensitive than Gram-positive bacteria to plant extracts. Between the two plants species studied, Lawsonia inermis extract showed more antibacterial activity compared to Mimosa pudica extract. PMID:21188055

Akter, A; Neela, F A; Khan, M S I; Islam, M S; Alam, M F

2010-05-01

127

Synthesis, antibacterial and antifungal activities of some N-nitroso-2,6-diarylpiperidin-4-one semicarbazones and QSAR analysis  

Microsoft Academic Search

A series of N-nitroso-2,6-diarylpiperidin-4-one semicarbazones and thiosemicarbazones were synthesized, characterized by IR, NMR and elemental analysis. All the compounds were screened for their antibacterial activity against Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus and Gram-negative bacteria Escherichia coli and fungi Candida albicans. These compounds have showed moderate and very good antibacterial activity. Quantitative Structure Activity Relationship (QSAR) analysis was performed for

T. Hemalatha; P. K. M. Imran; A. Gnanamani; S. Nagarajan

2008-01-01

128

Screening of Yemeni medicinal plants for antibacterial and cytotoxic activities.  

PubMed

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. The ethyl acetate extract of Lawsonia inermis was found to be the most active one against all bacteria in the test system. Other promising results could be obtained from extracts of Aloe perryi, Indigofera oblongifolia, Meriandra benghalensis and Ziziphus spina christi. Additionally, the ethanolic extracts of the 20 plants under investigation were tested for their cytotoxic effects on FL-cells using the neutral red assay. Extracts of Calotropis procera, Chenopodium murale, Pulicaria orientalis, Tribulus terrestris and Withania somniferum displayed a remarkable activity. PMID:11167035

Ali, N A; Jülich, W D; Kusnick, C; Lindequist, U

2001-02-01

129

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

130

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

131

A Microdomain for Protein Secretion in Gram-Positive Bacteria  

Microsoft Academic Search

Gram-positive bacteria face unique challenges in generating biologically active conformations for their exported proteins because they lack a dedicated compartment for folding secreted polypeptides. We have discovered that protein secretion by way of the general secretory (Sec) pathway in the important human pathogen Streptococcus pyogenes proceeds through a single microdomain. Unlike other mechanisms for asymmetry involving the Sec pathway, proteins

Jason Rosch; Michael Caparon

2004-01-01

132

Three-dimensional quantitative structure–activity relationship (3D-QSAR) studies of tricyclic oxazolidinones as antibacterial agents  

Microsoft Academic Search

Oxazolidinones exemplified by eprezolid and linezolid are a new class of antibacterials that are active against Gram positive and anaerobic bacteria including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE) and vancomycin resistant enterococci (VRE). In an effort to have a better antibacterial agent in the oxazolidinone class, we have performed three-dimensional quantitative structure–activity relationship (3D-QSAR) studies for a series

Bulusu Gopalakrishnan; Akash Khandelwal; Shaikh Abdul Rajjak; Natesan Selvakumar; Jagattaran Das; Sanjay Trehan; Javed Iqbal; Magadi Sitaram Kumar

2003-01-01

133

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

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 MIC(50) and MIC(90) of tedizolid against both methicillin-susceptible S. aureus (MSSA) and MRSA were 0.25 ?g/ml, compared with a MIC(50) of 1 ?g/ml and MIC(90) 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. PMID:22687509

Prokocimer, Philippe; Bien, Paul; Deanda, Carisa; Pillar, Chris M; Bartizal, Ken

2012-06-11

134

Antibacterial, anthelmintic and anti-amoebic activity in South African medicinal plants.  

PubMed

Hexane, ethanol and water extracts of plants used by South African traditional healers for treating stomach ailments were screened for antibacterial, anthelmintic and anti-amoebic activities. To evaluate antibacterial activity, the disc-diffusion assay was used against several Gram-positive and Gram-negative species. Minimal inhibitory concentration values were determined with a microdilution assay. Ethanolic extracts showed the greatest activity, and Gram-positive bacteria were the most susceptible microorganisms. The free-living nematode Caenorhabditis elegans was used in two different assays to evaluate anthelmintic activity. A microdilution technique was employed to investigate anti-amoebic activity against the enteropathogenic Entamoeba histolytica. These assays were suitable for the screening of a large number of extracts at one time. Several plants exhibited significant activity against these test organisms. PMID:10967478

McGaw, L J; Jäger, A K; van Staden, J

2000-09-01

135

Hyaluronidases of Gram-positive bacteria  

Microsoft Academic Search

Bacterial hyaluronidases, enzymes capable of breaking down hyaluronate, are produced by a number of pathogenic Gram-positive bacteria that initiate infections at the skin or mucosal surfaces. Since reports of the hyaluronidases first appeared, there have been numerous suggestions as to the role of the enzyme in the disease process. Unlike some of the other more well studied virulence factors, much

Wayne L. Hynes; Sheryl Lynne Walton

2000-01-01

136

Acyl-sulfamates Target the Essential Glycerol-Phosphate Acyltransferase (PlsY) in Gram-Positive Bacteria  

PubMed Central

PlsY is the essential first step in membrane phospholipid synthesis of Gram-positive pathogens. PlsY catalyzes the transfer of the fatty acid from acyl-phosphate to the 1-position of glycerol-3-phosphate to form the first intermediate in membrane biogenesis. A series of non-metabolizable, acyl-sulfamate analogs of the acyl-phosphate PlsY substrate were prepared and evaluated as inhibitors of Staphylococcus aureus PlsY and for their Gram-positive antibacterial activities. From this series phenyl (8-phenyloctanoyl) sulfamate had the best overall profile, selectively inhibiting S. aureus phospholipid biosynthesis and causing the accumulation of both long-chain fatty acids and acyl-acyl carrier protein intermediates demonstrating that PlsY was the primary cellular target. Bacillus anthracis was unique in being more potently inhibited by long chain acyl-sulfamates than other bacterial species. However, it is shown that Bacillus anthracis PlsY is not more sensitive to the acyl-sulfamates than S. aureus PlsY. Metabolic profiling showed that B. anthracis growth inhibition by the acyl-sulfamates was not specific for lipid synthesis illustrating that the amphipathic acyl-sulfamates can also have off-target effects in Gram-positive bacteria. Nonetheless, this study further advances PlsY as a druggable target for the development of novel antibacterial therapeutics, through the discovery and validation of the probe compound phenyl (8-phenyloctanoyl) sulfamate as a S. aureus PlsY inhibitor.

Cherian, Philip; Yao, Jiangwei; Leonardi, Roberta; Maddox, Marcus M.; Luna, Vicki A.; Rock, Charles O.; Lee, Richard E.

2012-01-01

137

Acyl-sulfamates target the essential glycerol-phosphate acyltransferase (PlsY) in Gram-positive bacteria.  

PubMed

PlsY is the essential first step in membrane phospholipid synthesis of Gram-positive pathogens. PlsY catalyzes the transfer of the fatty acid from acyl-phosphate to the 1-position of glycerol-3-phosphate to form the first intermediate in membrane biogenesis. A series of non-metabolizable, acyl-sulfamate analogs of the acyl-phosphate PlsY substrate were prepared and evaluated as inhibitors of Staphylococcus aureus PlsY and for their Gram-positive antibacterial activities. From this series phenyl (8-phenyloctanoyl) sulfamate had the best overall profile, selectively inhibiting S. aureus phospholipid biosynthesis and causing the accumulation of both long-chain fatty acids and acyl-acyl carrier protein intermediates demonstrating that PlsY was the primary cellular target. Bacillus anthracis was unique in being more potently inhibited by long chain acyl-sulfamates than other bacterial species. However, it is shown that Bacillus anthracis PlsY is not more sensitive to the acyl-sulfamates than S. aureus PlsY. Metabolic profiling showed that B. anthracis growth inhibition by the acyl-sulfamates was not specific for lipid synthesis illustrating that the amphipathic acyl-sulfamates can also have off-target effects in Gram-positive bacteria. Nonetheless, this study further advances PlsY as a druggable target for the development of novel antibacterial therapeutics, through the discovery and validation of the probe compound phenyl (8-phenyloctanoyl) sulfamate as a S. aureus PlsY inhibitor. PMID:22795901

Cherian, Philip T; Yao, Jiangwei; Leonardi, Roberta; Maddox, Marcus M; Luna, Vicki A; Rock, Charles O; Lee, Richard E

2012-06-23

138

In Vitro and In Vivo Antibacterial Activities of DC159a, a New Fluoroquinolone  

Microsoft Academic Search

DC-159a is a new 8-methoxy fluoroquinolone that possesses a broad spectrum of antibacterial activity, with extended activity against gram-positive pathogens, especially streptococci and staphylococci from patients with community-acquired infections. DC-159a showed activity against Streptococcus spp. (MIC90, 0.12 g\\/ml) and inhibited the growth of 90% of levofloxacin-intermediate and -resistant strains at 1 g\\/ml. The MIC90 so f DC-159a against Staphylococcus spp.

Kazuki Hoshino; Kazue Inoue; Yoichi Murakami; Yuichi Kurosaka; Kenji Namba; Yoshinori Kashimoto; Saori Uoyama; Ryo Okumura; Saito Higuchi; Tsuyoshi Otani

2008-01-01

139

[Antioxidant and antibacterial activities of dimeric phenol compounds].  

PubMed

We studied the antioxidant and antibacterial activities of monomeric and dimeric phenol compounds. Dimeric compounds had higher antioxidant activities than monomeric compounds. Electron spin resonance spin-trapping experiments showed that phenol compounds with an allyl substituent on their aromatic rings directly scavenged superoxide, and that only eugenol trapped hydroxyl radicals. We developed a generation system of the hydroxyl radical without using any metals by adding L-DOPA and DMPO to PBS or MiliQ water in vitro. We found that eugenol trapped hydroxyl radicals directly and is metabolized to a dimer. On the other hand, dipropofol, a dimer of propofol, has strong antibacterial activity against Gram-positive bacteria. However, it lacks solubility in water and this property is assumed to limit its efficacy. We tried to improve the solubility and found a new solubilization method of dipropofol in water with the addition of a monosaccharide or ascorbic acid. PMID:18670180

Ogata, Masahiro

2008-08-01

140

[Investigation of antibacterial activity of sertralin].  

PubMed

Sertralin is a psychotropic drug which acts by inhibiting the selective serotonin re-uptake in the synaptic area. Previous studies have shown that some antidepressant agents have antibacterial activity. The aim of this study was to investigate the in vitro antibacterial activity of sertralin. A total of 224 bacterial strains isolated from clinical specimens together with standard control strains were included to the study. The antibacterial activity of sertralin was determined by microdilution method in Mueller-Hinton broth according to the Clinical and Laboratory Standards Institute (CLSI) guideline. The minimum inhibitory concentration (MIC) values were found to be 4-32 microg/ml for 22 methicillin-susceptible Staphylococcus aureus strains, 16-32 microg/ml for 25 methicillin-resistant S. aureus strains, 8-32 microg/ml for 20 methicillin-resistant coagulase-negative staphylococci strains, 16-32 microg/ml for 4 vancomycin-susceptible Enterococcus faecalis strains, 0.5-32 microg/ml for 10 vancomycin-susceptible Enterococcus faecium strains, 2-8 microg/ml for 12 vancomycin-resistant E. faecium strains, 16-128 microg/ml for 21 Acinetobacter baumannii strains, 4->128 microg/ml for 20 Klebsiella pneumoniae strains, 0.25-128 microg/ml for 24 Escherichia coil strains, 64->128 microg/ml for 22 Pseudomonas aeruginosa strains, 128->128 microg/ml for 2 Proteus vulgaris strains, 64->128 microg/ml for 8 Proteus mirabilis strains, 32->128 microg/ml for 7 Stenotrophomonas maltophilia strains, 32-128 microg/ml for 21 Enterobacter cloacae strains and 8-128 microg/ml for 6 Enterobacter aerogenes strains. The MIC values of sertralin against standard strains were as follows; 16 microg/ml for S. aureus ATCC 29213 (methicillin-susceptible), 32 microg/ml for S. aureus ATCC 43300 (methicillin-resistant), 16 microg/ml for E. faecalis ATCC 29212, 32 microg/ml for K. pneumoniae ATCC 700603, 32 microg/ml for E. coli ATCC 25922 and > 128 microg/ml for P. aeruginosa ATCC 27853. Sertralin has showed antibacterial activity mainly against gram-positive bacteria, and it was surprising that MIC values of vancomycin-resistant enterococci were lower than those of vancomycin-susceptible ones. Further in vivo and in vitro studies are required to provide reliable data about the use of sertralin as an adjuvant agent in the antibacterial treatment of infections caused by multidrug-resistant bacteria. PMID:20084919

Coban, Ahmet Yilmaz; Tanriverdi Cayci, Yeliz; Kele? Uluda?, Selma; Durupinar, Belma

2009-10-01

141

The synthesis of chitosan-based silver nanoparticles and their antibacterial activity  

Microsoft Academic Search

Chitosan-based silver nanoparticles were synthesized by reducing silver nitrate salts with nontoxic and biodegradable chitosan. The silver nanoparticles thus obtained showed highly potent antibacterial activity toward both Gram-positive and Gram-negative bacteria, comparable with the highly active precursor silver salts. Silver-impregnated chitosan films were formed from the starting materials composed of silver nitrate and chitosan via thermal treatment. Compared with pure

Dongwei Wei; Wuyong Sun; Weiping Qian; Yongzhong Ye; Xiaoyuan Ma

2009-01-01

142

Pili in Gram-positive pathogens  

Microsoft Academic Search

Most bacterial pathogens have long filamentous structures known as pili or fimbriae extending from their surface. These structures are often involved in the initial adhesion of the bacteria to host tissues during colonization. In Gram-negative bacteria, pili are typically formed by non-covalent interactions between pilin subunits. By contrast, the recently discovered pili in Gram-positive pathogens are formed by covalent polymerization

Michèle A. Barocchi; Immaculada Margarit; Rino Rappuoli; John L. Telford; Guido Grandi

2006-01-01

143

Antibacterial Activity of 2-(2?,4?-Dibromophenoxy)-4,6-dibromophenol from Dysidea granulosa  

PubMed Central

2-(2?,4?-Dibromophenoxy)-4,6-dibromophenol isolated from the marine sponge Dysidea granulosa (Bergquist) collected off the coast of Lakshadweep islands, Indian Ocean, exhibited potent and broad spectrum in-vitro antibacterial activity, especially against methicillin resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), vancomycin resistant Enterococci (VRE), vancomycin sensitive Enterococci (VSE) and Bacillus spp. Minimal inhibitory concentration (MIC) was evaluated against 57 clinical and standard strains of Gram positive and Gram negative bacteria. The observed MIC range was 0.117–2.5 ?g/mL against all the Gram positive bacteria and 0.5–2 ?g/mL against Gram negative bacteria. The in-vitro antibacterial activity observed was better than that of the standard antibiotic linezolid, a marketed anti-MRSA drug. The results establish 2-(2?,4?-dibromophenoxy)-4,6-dibromophenol, as a potential lead molecule for anti-MRSA and anti-VRE drug development.

Shridhar, Divya M. P.; Mahajan, Girish B.; Kamat, Vijayendra P.; Naik, Chandrakant G.; Parab, Rajashri R.; Thakur, Nidhi R.; Mishra, Prabhu D.

2009-01-01

144

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

145

In vitro evaluation of Datura innoxia (thorn-apple) for potential antibacterial activity  

Microsoft Academic Search

Various parts of Datura innoxia were examined for potential antibacterial activity by preparing their crude aqueous and organic extracts against Gram-negative\\u000a bacteria (Escherichia coli and Salmonella typhi) and Gram-positive bacteria (Bacillus cereus, Bacillus subtilis and Staphylococcus aureus). The results of agar well diffusion assay indicated that the pattern of inhibition depends largely upon the plant part,\\u000a solvent used for extraction

P. Kaushik; Pankaj Goyal

2008-01-01

146

Fighting infections due to multidrug-resistant Gram-positive pathogens.  

PubMed

Growing bacterial resistance in Gram-positive pathogens means that what were once effective and inexpensive treatments for infections caused by these bacteria are now being seriously questioned, including penicillin and macrolides for use against pneumococcal infections and-in hospitals-oxacillin for use against staphylococcal infections. As a whole, multidrug-resistant (MDR) Gram-positive pathogens are rapidly becoming an urgent and sometimes unmanageable clinical problem. Nevertheless, and despite decades of research into the effects of antibiotics, the actual risk posed to human health by antibiotic resistance has been poorly defined; the lack of reliable data concerning the outcomes resulting from antimicrobial resistance stems, in part, from problems with study designs and the methods used in resistence determination. Surprisingly little is known, too, about the actual effectiveness of the many types of intervention aimed at controlling antibiotic resistance. New antibiotics active against MDR Gram-positive pathogens have been recently introduced into clinical practice, and the antibiotic pipeline contains additional compounds at an advanced stage of development, including new glycopeptides, new anti-methicillin-resistant Staphylococcus aureus (MRSA) beta-lactams, and new diaminopyrimidines. Many novel antimicrobial agents are likely to be niche products, endowed with narrow antibacterial spectra and/or targeted at specific clinical problems. Therefore, an important educational goal will be to change the current, long-lasting attitudes of both physicians and customers towards broad-spectrum and multipurpose compounds. Scientific societies, such as the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), must play a leading role in this process. PMID:19335367

Cornaglia, G

2009-03-01

147

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

148

Enhanced antibacterial activities of leonuri herba extracts containing silver nanoparticles.  

PubMed

We report an efficient and powerful green process to enhance the antibacterial activities of the Leonuri herba extract. Plant sources, especially leaves and herbs, are precious for the generation of gold and silver nanoparticles. Various kinds of polyphenols and hydroxyl groups are capable of processing a reduction reaction to generate metals from its corresponding salts. We have prepared gold and silver nanoparticles with 70% ethanol and water extracts. No other toxic chemicals were utilized and the extracts played dual roles as reducing and stabilizing agents. For the generation of nanoparticles, both oven incubation and autoclaving methods were applied and the reaction conditions were optimized. Surface plasmon resonance band indicated that the formation of nanoparticles was successful. Images of high-resolution transmission electron microscopy revealed mostly spherical nanoparticles ranging from 9.9 to 13.0?nm in size. A water extract containing silver nanoparticles exhibited remarkable (approximately 127-fold) enhancement in antibacterial activities against Pseudomonas aeruginosa, Escherichia coli and Enterobacter cloacae when compared with the water extract alone. In addition, antibacterial activity towards Gram-negative bacteria was greater than that against Gram-positive bacteria. The process reported here has the potential to be a new approach to improve the antibacterial activities of plant extracts. PMID:22170803

Im, A-Rang; Han, Lina; Kim, E Ray; Kim, Jinwoong; Kim, Yeong Shik; Park, Youmie

2011-12-15

149

Antimicrobial activity of ceftobiprole against Gram-negative and Gram-positive pathogens: results from INVITA-A-CEFTO Brazilian study  

Microsoft Academic Search

Ceftobiprole is a broad-spectrum cephalosporin with potent activity against staphylococci, including those resistant to oxacillin, as well as against most Gram-negative bacilli including Pseudomonas aeruginosa. In this study, the in vitro activity of ceftobiprole and comparator agents was tested against bacterial isolates recently collected from Brazilian private hospitals. A total of 336 unique bacterial isolates were collected from hospitalized patients

Rosângela Ferraz Cereda; Heber Dias Azevedo; Raquel Girardello; Danilo Elias Xavier; Ana C. Gales

2011-01-01

150

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

Microsoft Academic Search

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

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

151

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

2007-03-15

152

In Vitro Activities of Novel Oxapenems, Alone and in Combination with Ceftazidime, against Gram-Positive and Gram-Negative Organisms  

PubMed Central

Four novel oxapenem compounds (i.e., AM-112, AM-113, AM-114, and AM-115) were investigated for their ?-lactamase inhibitory activity against a panel of isolated class A, C, and D enzymes, which included expanded-spectrum ?-lactamase enzymes (ESBLs). The oxapenems were potent ?-lactamase inhibitors. Activity varied within the group, with AM-113 and AM-114 proving to be the most active compounds. The 50% inhibitory concentrations for these agents were up to 100,000-fold lower than that of clavulanic acid against class C and D enzymes. As a group, the oxapenems were more potent than clavulanic acid against enzymes from all classes. The ability of these compounds to protect ceftazidime from hydrolysis by ?-lactamase-producing strains was evaluated by MIC tests that combined ceftazidime and each oxapenem in a 1:1 or 2:1 ratio. The oxapenems markedly reduced the MICs for ceftazidime against class C hyperproducing strains and strains producing TEM- and SHV-derived ESBLs. There was little difference between the activity of 1:1 and 2:1 combinations of ceftazidime and oxapenem. The oxapenems failed to enhance the activity of ceftazidime against derepressed AmpC-producing Pseudomonas aeruginosa strains.

Jamieson, Conor E.; Lambert, Peter A.; Simpson, Iain N.

2003-01-01

153

Macrophage Migration Inhibitory Factor is a Critical Mediator of the Activation of Immune Cells by Exotoxins of Gram-Positive Bacteria  

Microsoft Academic Search

Discovered in the early 1960s as a T cell cytokine, the protein mediator known as macrophage migration inhibitory factor (MIF) has been found recently to be a pituitary peptide released during the physiological stress response, a proinflammatory macrophage cytokine secreted after LPS stimulation, and a T cell product expressed as part of the antigen-dependent activation response. We report herein that

Thierry Calandra; Lori A. Spiegel; Christine N. Metz; Richard Bucala

1998-01-01

154

Glycerol Monolaurate Antibacterial Activity in Broth and Biofilm Cultures  

PubMed Central

Background Glycerol monolaurate (GML) is an antimicrobial agent that has potent activity against gram-positive bacteria. This study examines GML antibacterial activity in comparison to lauric acid, in broth cultures compared to biofilm cultures, and against a wide range of gram-positive, gram-negative, and non-gram staining bacteria. Methodology/Principal Findings GML is ?200 times more effective than lauric acid in bactericidal activity, defined as a ?3 log reduction in colony-forming units (CFU)/ml, against Staphylococcus aureus and Streptococcus pyogenes in broth cultures. Both molecules inhibit superantigen production by these organisms at concentrations that are not bactericidal. GML prevents biofilm formation by Staphylococcus aureus and Haemophilus influenzae, as representative gram-positive and gram-negative organisms, tested in 96 well microtiter plates, and simultaneously is bactericidal for both organisms in mature biofilms. GML is bactericidal for a wide range of potential bacterial pathogens, except for Pseudomonas aeruginosa and Enterobacteriaceae. In the presence of acidic pH and the cation chelator ethylene diamine tetraacetic acid, GML has greatly enhanced bactericidal activity for Pseudomonas aeruginosa and Enterobacteriaceae. Solubilization of GML in a nonaqueous delivery vehicle (related to K-Y Warming®) enhances its bactericidal activity against S. aureus. Both R and S, and 1 and 2 position lauric acid derivatives of GML exhibit bactericidal activity. Despite year-long passage of Staphylococcus aureus on sub-growth inhibitory concentrations of GML (0.5 x minimum bactericidal concentration), resistance to GML did not develop. Conclusions/Significance GML may be useful as a broad-spectrum human or animal topical microbicide and may be useful as an environmental surface microbicide for management of bacterial infections and contamination.

Schlievert, Patrick M.; Peterson, Marnie L.

2012-01-01

155

Antibacterial Activity of Myristica fragrans against Oral Pathogens  

PubMed Central

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.

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

2012-01-01

156

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

2012-08-28

157

In Vitro Activities of Dalbavancin and 12 Other Agents against 329 Aerobic and Anaerobic Gram-Positive Isolates Recovered from Diabetic Foot Infections  

PubMed Central

Tests of dalbavancin's in vitro activity against 209 aerobic and 120 anaerobic isolates from pretreatment diabetic foot infections showed an MIC90 of ?0.125 ?g/ml against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and 120 anaerobes (Clostridium perfringens, other clostridia, Peptoniphilus asaccharolyticus, Finegoldia magna, and Anaerococcus prevotii), compared to respective MIC90s for MSSA and MRSA of 0.5 and 1 ?g/ml for vancomycin, 4 and 4 ?g/ml for linezolid, 0.5 and 0.5 ?g/ml for daptomycin, and 0.25 and >8 ?g/ml for clindamycin.

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

2006-01-01

158

Influence of pH, Heat and Enzymatic Treatments on the Activity of Antibacterial Substance in MRS and Milk Media Produced by Lactobacillus fermentum F6  

Microsoft Academic Search

This study aimed to investigate the influence of pH, heat and enzymatic treatments on the activity of antibacterial substance in MRS, skim soy milk and bovine milk media fermented by a potential probiotic Lactobacillus fermentum F6. The antibacterial activity of the culture supernatant of L. fermentum F6 was tested against a wide range of Gram-positive and Gram-negative pathogenic bacteria including

Yong ZHANG; Yong LIU; Yan BAO; He-ping ZHANG

2010-01-01

159

Antioxidative, antibrowning and antibacterial activities of sixteen floral honeys.  

PubMed

Commonly consumed honeys from sixteen different single floral sources were analyzed for their in vitro antioxidant capacities by several methods including DPPH, ABTS, FRAP, SASR and MDA assays. The total polyphenol contents varied among the tested honeys and were highly correlated to their antioxidant capacity values. The antioxidant capacity of Chinese milk vetch flower honeys was significantly higher than those of other flower honeys. All honeys tested were active in inhibiting the browning of apple homogenate and linden honey displayed the highest inhibition rate as 85%. When the antimicrobial activity of the investigated honeys was screened using Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), clover honey exhibited the strongest antibacterial activity as 2.2 mg mL(-1) kanamycin equivalent inhibition. PMID:21860856

Chang, Xin; Wang, Jiehua; Yang, Shaohui; Chen, Shan; Song, Yingjin

2011-08-22

160

Antibacterial activities of tellurium nanomaterials.  

PubMed

We prepared four differently shaped Te nanomaterials (NMs) as antibacterial reagents against Escherichia coli. By controlling the concentrations of hydrazine (N(2)H(4)) as reducing agent, NaCl, and temperature, we prepared Te nanowires, nanopencils, nanorices, and nanocubes. These four Te NMs resulted in a live/dead ratio of E. coli cells of less than 0.1, which is smaller than that of Ag nanoparticles. The order of antibacterial activity against E. coli is nanocubes ? nanorices > nanopencils ? nanowires. This is in good agreement with the concentration order of tellurite (TeO(3)(2-)) ions released from Te NMs in E. coli cells, revealing that TeO(3)(2-) ions account for the antibacterial activity of the four Te NMs. We found that spherical Te nanoparticles (32 nm in diameter) with TeO(3)(2-) ions were formed in the E. coli cells. Compared to Ag nanoparticles that are commonly used as antibacterial reagents, Te NMs have higher antibacterial activity and lower toxicity. Thus, Te NMs hold great practical potential as a new and efficient antibacterial agent. PMID:22438287

Lin, Zong-Hong; Lee, Chia-Hsin; Chang, Hsin-Yun; Chang, Huan-Tsung

2012-03-21

161

Synthesis and antibacterial activities of new 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octan-2,4-dione moiety.  

PubMed

The synthesis of a new series of 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octane-2,4-dione moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bateria are determined and the effect of substituent on the bicyclic ring as well as stereoisomerism was investigated. PMID:9361524

Nam, K H; Oh, C H; Ham, Y W; Lee, K S; Cho, J H

1997-08-01

162

Rose Bengal-decorated silica nanoparticles as photosensitizers for inactivation of gram-positive bacteria  

NASA Astrophysics Data System (ADS)

A new type of photosensitizer, made from Rose Bengal (RB)-decorated silica (SiO2-NH2-RB) nanoparticles, was developed to inactivate gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), with high efficiency through photodynamic action. The nanoparticles were characterized microscopically and spectroscopically to confirm their structures. The characterization of singlet oxygen generated by RB, both free and immobilized on a nanoparticle surface, was performed in the presence of anthracene-9,10-dipropionic acid. The capability of SiO2-NH2-RB nanoparticles to inactivate bacteria was tested in vitro on both gram-positive and gram-negative bacteria. The results showed that RB-decorated silica nanoparticles can inactivate MRSA and Staphylococcus epidermidis (both gram-positive) very effectively (up to eight-orders-of-magnitude reduction). Photosensitizers of such design should have good potential as antibacterial agents through a photodynamic mechanism.

Guo, Yanyan; Rogelj, Snezna; Zhang, Peng

2010-02-01

163

Synthesis and antibacterial activity of of silver nanoparticles  

NASA Astrophysics Data System (ADS)

Silver nanoparticles have been known to have inhibitory and bactericidal effects but the antimicrobial mechanism have not been clearly revealed. Here, we report on the synthesis of metallic nanoparticles of silver using wild strains of Penicillium isolated from environment. Kinetics of the formation of nanosilver was monitored using the UV-Vis. TEM micrographs showed the formation of silver nanoparticles in the range 10-100 nm. Obtained Ag nanoparticles were evaluated for their antimicrobial activity against the gram-positive and gram-negative bacteria. As results, Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were effectively inhibited. Nanosilver is a promising candidate for development of future antibacterial therapies because of its wide spectrum of activity.

Maliszewska, I.; Sadowski, Z.

2009-01-01

164

Antibacterial activity in blood cultures.  

PubMed Central

A total of 2,010 blood samples inoculated into tryptic soy broth were examined for antibacterial activity by means of a bioassay plate seeded with Bacillus subtilis spores. The size of the zone of inhibition on this plate was indicative of the degree of antibacterial activity. Current antibiotic therapy was confirmed by examination of chart records. Of the 2,010 blood cultures tested, 147 (7.3%) contained detectable levels of antibiotics; of these 147, 14 (9.5%) yielded growth of bacteria, and 133 (90.5%) remained negative. When the Antibiotic Removal Device (Marion Scientific, Div. Marion Laboratories, Inc., Kansas City, Mo.) was used, it eliminated the antibacterial activity but did not improve the recovery of bacteria from these cultures. Only bacteria resistant to the respective antibiotic were recovered from blood cultures that showed high levels of antibacterial activity (beta-lactam antibiotics, greater than 0.60 micrograms/ml; aminoglycosides, greater than 2 micrograms/ml; and tetracycline, greater than 4 micrograms/ml). Blood cultures showing low levels of antibacterial activity yielded both resistant and susceptible bacteria.

Rodriguez, F; Lorian, V

1985-01-01

165

Sortase enzymes in Gram-positive bacteria  

PubMed Central

Summary In Gram-positive bacteria proteins are displayed on the cell surface using sortase enzymes. These cysteine transpeptidases join proteins bearing an appropriate sorting signal to strategically positioned amino groups on the cell surface. Working alone, or in concert with other enzymes, sortases either attach proteins to the cross-bridge peptide of the cell wall or they link proteins together to form pili. Because surface proteins play a fundamental role in microbial physiology and are frequently virulence factors, sortase enzymes have been intensely studied since their discovery a little more than a decade ago. Based on their primary sequences and functions sortases can be partitioned into distinct families called class A to F enzymes. Most bacteria elaborate their surfaces using more than one type of sortase that function non-redundantly by recognizing unique sorting signals within their protein substrates. Here we review what is known about the functions of these enzymes and the molecular basis of catalysis. Particular emphasis is placed on ‘pilin’ specific class C sortases that construct structurally complex pili. Exciting new data have revealed that these enzymes are amazingly promiscuous in the substrates that they can employ and that there is a startling degree of diversity in their mechanism of action. We also review recent data that suggest that sortases are targeted to specific sites on the cell surface where they work with other sortases and accessory factors to properly function.

Spirig, Thomas; Weiner, Ethan M.; Clubb, Robert T.

2013-01-01

166

Aryl urea analogs with broad-spectrum antibacterial activity  

Microsoft Academic Search

The preparation and evaluation of novel aryl urea analogs as broad-spectrum antibacterial agents is described. Numerous compounds showed low micromolar minimum inhibitory concentrations (MIC) against both Gram-positive and Gram-negative bacteria. Selected analogs also exhibited in vivo efficacy in a lethal murine model of bacterial septicemia.

Punit P. Seth; Ray Ranken; Dale E. Robinson; Stephen A. Osgood; Lisa M. Risen; Elizabeth L. Rodgers; Michael T. Migawa; Elizabeth A. Jefferson; Eric E. Swayze

2004-01-01

167

Aryl urea analogs with broad-spectrum antibacterial activity.  

PubMed

The preparation and evaluation of novel aryl urea analogs as broad-spectrum antibacterial agents is described. Numerous compounds showed low micromolar minimum inhibitory concentrations (MIC) against both Gram-positive and Gram-negative bacteria. Selected analogs also exhibited in vivo efficacy in a lethal murine model of bacterial septicemia. PMID:15482926

Seth, Punit P; Ranken, Ray; Robinson, Dale E; Osgood, Stephen A; Risen, Lisa M; Rodgers, Elizabeth L; Migawa, Michael T; Jefferson, Elizabeth A; Swayze, Eric E

2004-11-15

168

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

169

Synthesis and antibacterial activity of novel phosphonium salts on the basis of pyridoxine.  

PubMed

A series of 13 phosphonium salts on the basis of pyridoxine derivatives were synthesized and their antibacterial activity against clinically relevant strains was tested in vitro. All compounds were almost inactive against gram-negative bacteria and exhibited structure-dependent activity against gram-positive bacteria. A crucial role of ketal protection group in phosphonium salts for their antibacterial properties was demonstrated. Among synthesized compounds 5,6-bis[triphenylphosphonio(methyl)]-2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine dichloride (compound 20) was found to be the most effective towards Staphylococcus aureus and Staphylococcus epidermidis strains (MIC 5?g/ml). The mechanism of antibacterial activity of this compound probably involves cell penetration and interaction with genomic and plasmid DNA. PMID:23683836

Pugachev, Mikhail V; Shtyrlin, Nikita V; Sysoeva, Lubov P; Nikitina, Elena V; Abdullin, Timur I; Iksanova, Alfiya G; Ilaeva, Alina A; Musin, Rashid Z; Berdnikov, Eugeny A; Shtyrlin, Yurii G

2013-04-29

170

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

2010-11-25

171

Design, synthesis, and antibacterial activity of novel pleuromutilin derivatives bearing an amino thiazolyl ring.  

PubMed

A series of novel pleuromutilin derivatives containing the amino thiazolyl ring were designed, synthesized, and evaluated for their antibacterial activities in vitro against Gram-positive clinical bacteria. All the target compounds showed better aqueous solubility compared with the lead compound (10). Most compounds displayed strong antibacterial activities against both susceptible and resistant bacteria, particularly for the compound (12f) which showed extraordinary antibacterial properties superior to amoxicillin and tiamulin. Molecular docking studies revealed that the amino thiazolyl ring, the side chains of the pleuromutilin derivatives, can be adopted in the binding pocket of the 50S ribosomal subunit near the mutilin core. Therefore, our novel findings may provide new insights into the design of novel pleuromutilin derivatives and lay the basis for further studies on these promising antibiotics for human clinical use. PMID:22532317

Ling, Yong; Wang, Xinyang; Wang, Hui; Yu, Jianghe; Tang, Junming; Wang, Donggeng; Chen, Guangtong; Huang, Jinhua; Li, Yuqin; Zheng, Heng

2012-04-25

172

Tuning the antibacterial activity of amphiphilic neamine derivatives and comparison to paromamine homologues.  

PubMed

Aminoglycosides are antibiotic drugs that act through binding to rRNA. In the search for antimicrobial amphiphilic aminoglycosides targeting bacterial membranes, we report here on the discovery of three dialkyl derivatives of the small aminoglycoside neamine active against susceptible and resistant Gram-positive and Gram-negative bacteria. One of these derivatives (R = 2-naphthylpropyl), which has good activity against MRSA and VRSA, showed a low toxicity in eukaryotic cells at 10 ?M. The synthesis of amphiphilic paromamine and neamine homologous derivatives pointed out the role of the 6'-amine function of the neamine core in the antibacterial effects. The optimal number of lipophilic substituents to be attached to the neamine core and the corresponding required lipophilicity determined here should permit a more selective targeting of bacterial membranes relative to eukaryotic membranes. This work revealed the existence of windows of lipophilicity necessary for obtaining strong antibacterial effects that should be of interest in the field of antibacterial amphiphilic aminoglycosides. PMID:24083676

Zimmermann, Louis; Bussière, Antoine; Ouberai, Myriam; Baussanne, Isabelle; Jolivalt, Claude; Mingeot-Leclercq, Marie-Paule; Décout, Jean-Luc

2013-10-01

173

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

2013-01-24

174

Synthesis and structure-activity relationships of novel amino/nitro substituted 3-arylcoumarins as antibacterial agents.  

PubMed

A new series of amino/nitro-substituted 3-arylcoumarins were synthesized and their antibacterial activity against clinical isolates of Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) was evaluated. Some of these molecules exhibited antibacterial activity against S. aureus comparable to the standards used (oxolinic acid and ampicillin). The preliminary structure-activity relationship (SAR) study showed that the antibacterial activity against S. aureus depends on the position of the 3-arylcoumarin substitution pattern. With the aim of finding the structural features for the antibacterial activity and selectivity, in the present manuscript different positions of nitro, methyl, methoxy, amino and bromo substituents on the 3-arylcoumarin scaffold were reported. PMID:23348993

Matos, Maria J; Vazquez-Rodriguez, Saleta; Santana, Lourdes; Uriarte, Eugenio; Fuentes-Edfuf, Cristina; Santos, Ysabel; Muñoz-Crego, Angeles

2013-01-24

175

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

176

Mannich bases of 7-piperazinylquinolones and kojic acid derivatives: Synthesis, in vitro antibacterial activity and in silico study.  

PubMed

Novel Mannich bases of 7-piperazinylquinolones with kojic acid and chlorokojic acid were designed as new quinolone antibacterials. All compounds showed significant in vitro antibacterial activity against both Gram-positive and Gram-negative bacteria. Particularly, chlorokojic derivative 2b was the most potent compound against Staphylococcus aureus and Pseudomonas aeruginosa (MIC values ?0.19 ?g/mL). Its activity was 4-8 times more than that of standard drug norfloxacin. The molecular docking study of compound 2b further supported the molecular basis of the designed compounds. PMID:23974018

Emami, Saeed; Ghafouri, Ebrahim; Faramarzi, Mohammad Ali; Samadi, Nasrin; Irannejad, Hamid; Foroumadi, Alireza

2013-08-11

177

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

178

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

179

Antibacterial activity of licochalcone A against spore-forming bacteria.  

PubMed

Licochalcone A was isolated from the roots of licorice, Glycyrrhiza inflata, which has various uses in the food and pharmaceutical industries; isolation was followed by extraction with ethanol and column chromatography with silica gel. In this study, the activities of licochalcone A against some food contaminant microorganisms were evaluated in vitro. The vegetative cell growth of Bacillus subtilis was inhibited in a licochalcone A concentration-dependent manner and was completely prevented by 3 micrograms of licochalcone A/ml. Licochalcone A showed a high level of resistance to heating at 80 to 121 degrees C for 15 min. Licochalcone A did not inhibit the germination of heat-treated spores of B. subtilis induced by L-alanine. Licochalcone A showed effects against all gram-positive bacteria tested and especially was effective against all Bacillus spp. tested, with MICs of 2 to 3 micrograms/ml, but was not effective against gram-negative bacteria or eukaryotes at 50 micrograms/ml. Although the cationic antimicrobial peptides protamine and epsilon-poly-L-lysine resulted in the loss of antimicrobial activity in the presence of either 3% (wt/vol) NaCl or protease at 20 micrograms/ml, the antibacterial activity of licochalcone A was resistant to these conditions. Thus, licochalcone A could be a useful compound for the development of antibacterial agents for the preservation of foods containing high concentrations of salts and proteases, in which cationic peptides might be less effective. PMID:11959549

Tsukiyama, Ryo-Ichi; Katsura, Harumi; Tokuriki, Nozomu; Kobayashi, Makio

2002-05-01

180

[Antimicrobial susceptibility of clinical isolates of aerobic gram-positive cocci and anaerobic bacteria in 2008].  

PubMed

The activity of antibacterial agents against aerobic Gram-positive cocci (25 genus or species, 1029 strains) and anaerobic bacteria (21 genus or species, 187 strains) isolated from clinical specimens in 2008 at 16 clinical facilities in Japan were studied using either broth microdilution or agar dilution method. The ratio of methicillin-resistant strains among Staphylococcus aureus and Staphylococcus epidermidis was 59.6% and 81.2%, suggesting that resistant strains were isolated at high frequency. Vancomycin (VCM), linezolid (LZD) and quinupristin/dalfopristin (QPR/DPR) had good antibacterial activity against methicillin-resistant S. aureus and methicillin-resistant S. epidermidis, with MIC90s of < or = 2 microg/mL. The ratio of penicillin (PC) intermediate and resistant strains classified by mutations of PC-binding proteins among Streptococcus pneumoniae was 92.0% that was highest among our previous reports. Cefpirome, carbapenems, VCM, teicoplanin (TEIC), LZD and QPR/DPR had MIC90s of < or = 1 microg/mL against PC-intermediate and resistant S. pneumoniae strains. Against all strains of Enterococcus faecalis and Enterococcus faecium, the MICs of VCM and TEIC were under 2 microg/mL, and no resistant strain was detected, suggesting that these agents had excellent activities against these species. 15.9% of E. faecalis strains and 1.2% of E. faecium strains showed intermediate to LZD. 17.1% of E. faecium strains showed intermediate or resistant to QPR/DPR. Against all strains of Clostridium difficile, the MIC of VCM was under 1 microg/mL, suggesting that VCM had excellent activity. Carbapenems showed good activity against Clostridiales, Bacteroides spp., and Prevotella spp., but one strain of Bacteroides fragilis showed resistant to carbapenems. And so, the susceptibility of this species should be well-focused in the future at detecting continuously. PMID:22808693

Yoshida, Isamu; Yamaguchi, Takahiro; Kudo, Reiko; Fuji, Rieko; Takahashi, Choichiro; Oota, Reiko; Kaku, Mitsuo; Kunishima, Hiroyuki; Okada, Masahiko; Horikawa, Yoshinori; Shiotani, Joji; Kino, Hiroyoshi; Ono, Yuka; Fujita, Shinichi; Matsuo, Shuji; Kono, Hisashi; Asari, Seishi; Toyokawa, Masahiro; Kusano, Nobuchika; Nose, Motoko; Horii, Toshinobu; Tanimoto, Ayako; Miyamoto, Hitoshi; Saikawa, Tetsunori; Hiramatsu, Kazufumi; Kohno, Shigeru; Yanagihara, Katsunori; Yamane, Nobuhisa; Nakasone, Isamu; Maki, Hideki; Yamano, Yoshinori

2012-02-01

181

[Antimicrobial susceptibility of clinical isolates of aerobic Gram-positive cocci and anaerobic bacteria in 2006].  

PubMed

The activity of antibacterial agents against aerobic Gram-positive cocci (26 species, 1022 strains) and anaerobic bacteria (23 species, 184 strains) isolated from clinical specimens in 2006 at 16 clinical facilities in Japan were studied using either broth microdilution or agar dilution method. The ratio of methicillin-resistant strains among Staphylococcus aureus and Staphylococcus epidermidis was 53.0% and 65.8%, suggesting that resistant strains were isolated at high frequency. Vancomycin (VCM) and quinupristin/dalfopristin (QPR/DPR) had good antibacterial activity against methicillin-resistant S. aureus and methicillin-resistant S. epidermidis, with MIC90s of < or = 2 micrcog/mL. The ratio of penicillin (PC) intermediate and resistant strains classified by mutations of PC-binding proteins among Streptococcus pneumoniae was 87.6%. Ceftriaxone, cefpirome, cefepime, carbapenem antibiotics, VCM, teicoplanin, linezolid(LZD) and QPR/DPR had MIC90s of < or = 1 microg/mL against PC-intermediate and resistant S. pneumoniae strains. Against all strains of Enterococcus faecalis and Enterococcus faecium, the MICs of VCM and TEIC were under 2 microg/mL, and no resistant strain was detected, suggesting that these agents had excellent activities against these species. 10.9% of E. faecalis strains or 3.5% of E. faecium strains showed intermediate or resistant to LZD. 24.4% of E. faecium strains showed intermediate or resistant to QPR/DPR. Against all strains of Clostridium difficile, the MIC of VCM were under 1 microg/mL, suggesting that VCM had excellent activity against C. difficile. Carbapenems showed good activity against Peptococcaceae, Bacteroides spp., and Prevotella spp. However since several strains of Bacteroides fragilis showed resistant to carbapenems and the susceptibility of this species should be well-focused in the future. PMID:21425596

Yamaguchi, Takahiro; Yoshida, Isamu; Itoh, Yoshihisa; Tachibana, Mineji; Takahashi, Choichiro; Kaku, Mitsuo; Kanemitsu, Keiji; Okada, Masahiko; Horikawa, Yoshinori; Shiotani, Joji; Kino, Hiroyoshi; Ono, Yuka; Baba, Hisashi; Matsuo, Shuji; Asari, Seishi; Toyokawa, Masahiro; Matsuoka, Kimiko; Kusano, Nobuchika; Nose, Motoko; Murase, Mitsuharu; Miyamoto, Hitoshi; Saikawa, Tetsunori; Hiramatsu, Kazufumi; Kohno, Shigeru; Yanagihara, Katsunori; Yamane, Nobuhisa; Nakasone, Isamu; Maki, Hideki; Yamano, Yoshinori

2010-12-01

182

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

183

Identification, Evolution, and Essentiality of the Mevalonate Pathway for Isopentenyl Diphosphate Biosynthesis in Gram-Positive Cocci  

PubMed Central

The mevalonate pathway and the glyceraldehyde 3-phosphate (GAP)–pyruvate pathway are alternative routes for the biosynthesis of the central isoprenoid precursor, isopentenyl diphosphate. Genomic analysis revealed that the staphylococci, streptococci, and enterococci possess genes predicted to encode all of the enzymes of the mevalonate pathway and not the GAP-pyruvate pathway, unlike Bacillus subtilis and most gram-negative bacteria studied, which possess only components of the latter pathway. Phylogenetic and comparative genome analyses suggest that the genes for mevalonate biosynthesis in gram-positive cocci, which are highly divergent from those of mammals, were horizontally transferred from a primitive eukaryotic cell. Enterococci uniquely encode a bifunctional protein predicted to possess both 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and acetyl-CoA acetyltransferase activities. Genetic disruption experiments have shown that five genes encoding proteins involved in this pathway (HMG-CoA synthase, HMG-CoA reductase, mevalonate kinase, phosphomevalonate kinase, and mevalonate diphosphate decarboxylase) are essential for the in vitro growth of Streptococcus pneumoniae under standard conditions. Allelic replacement of the HMG-CoA synthase gene rendered the organism auxotrophic for mevalonate and severely attenuated in a murine respiratory tract infection model. The mevalonate pathway thus represents a potential antibacterial target in the low-G+C gram-positive cocci.

Wilding, E. Imogen; Brown, James R.; Bryant, Alexander P.; Chalker, Alison F.; Holmes, David J.; Ingraham, Karen A.; Iordanescu, Serban; So, Chi Y.; Rosenberg, Martin; Gwynn, Michael N.

2000-01-01

184

Genetic features of circular bacteriocins produced by Gram-positive bacteria.  

PubMed

This review highlights the main genetic features of circular bacteriocins, which require the co-ordinated expression of several genetic determinants. In general terms, it has been demonstrated that the expression of such structural genes must be combined with the activity of proteins involved in maturation (cleavage/circularization) and secretion outside the cell via different transporter systems, as well as multifaceted immunity mechanisms essential to ensuring the bacteria's self-protection against such strong inhibitors. Several circular antibacterial peptides produced by Gram-positive bacteria have been described to date, including enterocin AS-48, from Enterococcus faecalis S-48 (the first one characterized), gassericin A, from Lactobacillus gasseri LA39, and a similar one, reutericin 6, from Lactobacillus reuteri LA6, butyrivibriocin AR10, from the ruminal anaerobe Butyrivibrio fibrisolvens AR10, uberolysin, from Streptococcus uberis, circularin A, from Clostridium beijerinckii ATCC 25752, and subtilosin A, from Bacillus subtilis. We summarize here the progress made in the understanding of their principal genetic features over the last few years, during which the functional roles of circular proteins with wide biological activity have become clearer. PMID:18034824

Maqueda, Mercedes; Sánchez-Hidalgo, Marina; Fernández, Matilde; Montalbán-López, Manuel; Valdivia, Eva; Martínez-Bueno, Manuel

2007-11-20

185

Nanostructured Ag4O4 films with enhanced antibacterial activity  

NASA Astrophysics Data System (ADS)

Ag4O4 (i.e. silver(I)-silver(III) oxide) thin films with tailored structure and morphology at the nanoscale have been grown by reactive pulsed laser deposition (PLD) in an oxygen-containing atmosphere and they are shown to exhibit a very strong antibacterial activity towards Gram-negative bacteria (E. coli) and to completely inhibit the growth of Gram-positive bacteria (S. aureus). The formation of this particular high-valence silver oxide is explained in terms of the reactions occurring during the expansion of the ablated species in the reactive atmosphere, leading to the formation of low-stability Ag-O dimers and atomic oxygen, providing reactive species at the substrate where the film grows. PLD is shown to allow control of the structure (i.e. crystallinity and grain size) and of the morphology of the films, from compact and columnar to foam-like, thus allowing the deposition of nanocrystalline films with increased porosity and surface area. The antibacterial action towards E. coli is demonstrated and is shown to be superior to that of nanostructured Ag-based medical products. This can be related to the release of Ag ions with high oxidation number, which are known to be very reactive towards bacteria, and to the peculiar morphology at the nanoscale resulting in a large effective surface area.

Dellasega, D.; Facibeni, A.; Di Fonzo, F.; Bogana, M.; Polissi, A.; Conti, C.; Ducati, C.; Casari, C. S.; Bassi, A. Li; Bottani, C. E.

2008-11-01

186

Antioxidant, antibacterial and antigiardial activities of Walsura robusta Roxb.  

PubMed

Walsura robusta Roxb. (Family: Meliaceae) is a well-known multi-purpose medicinal plant, and has been employed for a wide range of disease conditions without documented scientific data. In the current study, four pure isolated compounds, 3,4,5-trimethoxyphenyl beta-D-glucopyranoside (1), turpinionoside A (2), (+)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (3) and (-)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (4), were isolated from the leaves and twigs of W. robusta. Biological evaluation for free radical scavenging, antibacterial and antigiardial activities was performed. We investigated antioxidant effects of the crude extracts as well as the isolated compounds using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), hydroxyl radical (OH), and superoxide anion (O(2)) scavenging assays. Three phenolic glucosides (1, 3 and 4) were found to possess strong antioxidant activity. They scavenged DPPH(*) with IC(50) values in the range of 51.5-86.6 microM. We also detected the superoxide dismutase-like activities in compounds 3 and 4 which are lignan glucosides, demonstrating potent superoxide scavenging activity with IC(50) values in the range of 0.8 and 0.7 microM, respectively. Other biological activities including antibacterial and antigiardial assays were carried out. Preliminary results demonstrated that most extracts, except the diethyl ether extract, exhibited inhibition zones against all Gram-positive bacteria including Bacillus cereus, Staphylococcus aureus, Streptococcus mutans, and S. pyogenes. Aqueous extracts of this plant species could inhibit Gram-positive and some Gram-negative bacteria such as Escherichia coli, Salmonella typhi and Shigella sonnei. However, the determination of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of W. robusta on all tested bacterial strains showed only weak activity, and their MBCs were greater than 25 mg mL(-1). For antigiardial activity, incubation with 2 x 10(5) trophozoites mL(-1) of the culture medium with the crude extracts at concentration ranged from 31.25 to 1000 microg mL(-1) demonstrated no activity (MIC > 1000 microg mL(-1)). PMID:20461627

Voravuthikunchai, Supayang P; Kanchanapoom, Tripetch; Sawangjaroen, Nongyao; Hutadilok-Towatana, Nongporn

2010-05-01

187

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

2013-06-07

188

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

PubMed

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 antibacterial activities against most pathogens using broth microdilution method. Maximum activity of Thymus vulgaris and Pimpinella anisum essential oils and methanol extracts (MIC 15.6 and 62.5mug/ml) were observed against Staphylococcus aureus, Bacillus cereus and Proteus vulgaris. Combinations of essential oils and methanol extracts showed an additive action against most tested pathogens especially Pseudomonas aeruginosa. PMID:18226481

Al-Bayati, Firas A

2007-12-14

189

Isothiazolopyridones: synthesis, structure, and biological activity of a new class of antibacterial agents.  

PubMed

We report the syntheses of first-generation derivatives of isothiazolopyridones and their in vitro evaluation as antibacterial agents. These compounds, containing a novel heterocyclic nucleus composed of an isothiazolone fused to a quinolizin-4-one (at C-2 and C-3 of the quinolizin-4-one), were prepared using a sequence of seven synthetic transformations. The solid-state structure of 7-chloro-9-ethyl-1-thia-2,4a-diazacyclopenta[b]naphthalene-3,4-dione was determined by X-ray diffraction. The prepared derivatives of desfluoroisothiazolopyridones exhibited (a) antibacterial activity against Gram-negative and Gram-positive organisms, (b) inhibitory activities against DNA gyrase and topoisomerase IV, and (c) no inhibitory activity against human topoisomerase II. PMID:16392790

Wiles, Jason A; Hashimoto, Akihiro; Thanassi, Jane A; Cheng, Jijun; Incarvito, Christopher D; Deshpande, Milind; Pucci, Michael J; Bradbury, Barton J

2006-01-12

190

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

191

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

192

Assembly of pili in Gram-positive bacteria  

Microsoft Academic Search

The formation of adhesive pili on the surface of Gram-negative bacteria has been studied in detail, whereas the pilus assembly pathways in Gram-positive bacteria remain to be characterized. Gram-positive microbes use the cell wall peptidoglycan as a surface organelle for the covalent attachment of proteins; a strategy that involves sorting signals of surface protein precursors and sortase, a transpeptidase that

Hung Ton-That; Olaf Schneewind

2004-01-01

193

Chemical composition and antibacterial activity of essential oils from Myrcia alagoensis (Myrtaceae).  

PubMed

The chemical composition and antibacterial activity of essential oils obtained from fresh and dried leaves of Myrcia alagoensis O. Berg, collected in a secondary forest remnant in north-eastern Brazil, was compared. The essential oils were obtained by hydrodistillation from fresh and dried leaves, and analysed by GC/FID and GC/MS. The antimicrobial properties of the oils were investigated against five bacteria by determination of the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The essential oils were rich in cyclic sesquiterpenes, such as germacrene B, with antibiotic action against Gram-positive and Gram-negative bacteria. The drying process after collection interfered with the chemical composition and antibacterial activity of the assessed samples. PMID:23513746

Silva, Aline do N; Uetanabaro, Ana Paula T; Lucchese, Angélica M

2013-02-01

194

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

2013-05-14

195

Phenolic Content, Antioxidant Activity, Antibacterial Activity and Phytochemical Composition of Garcinia lancifolia.  

PubMed

Garcinia lancifolia (Clusiaceae) is an unexplored medicinal plant used as stomachic, diuretic and its fruit is used to cure dysentery and diarrhoea. The acidic fruits are used to prepare juice, pickle and curries. The phytochemical analysis of different extracts of G. lancifolia leaf, stem and fruit revealed the presence of tannins, saponins, flavonoids, terpenoids, alkaloids and cardiac glycosides. The high phenolic content was observed in the methanol extract of leaf followed by methanol extract of stem and dichloromethane extract of leaf. The G. lancifolia fruit juice exhibited high antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Micrococcus luteus, Streptococcus mutans, Bacillus mycoides and Bacillus subtilis. The methanol extract of fruit pulp was also very effective against Gram-positive bacteria when compared with Gram-negative bacteria. The radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl was highest in fruit juice followed by methanol extract of leaf and stem. All extracts showed concentration-dependent increase in the antioxidant activity. PMID:23439879

Policegoudra, R S; Saikia, S; Das, J; Chattopadhyay, P; Singh, L; Veer, V

2012-05-01

196

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

197

Antibacterial activity of eight Brazilian annonaceae plants  

Microsoft Academic Search

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?µg\\/mL. The most active extracts were those

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

2006-01-01

198

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

199

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

200

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

2012-06-29

201

Antibacterial, antifungal and cytotoxic activities of amblyone isolated from Amorphophallus campanulatus  

PubMed Central

Objective: To assess the in vitro antibacterial, antifungal and cytotoxic activities of amblyone, a triterpenoid isolated from Amorphophallus campanulatus (Roxb). Methods: Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Cytotoxicity was determined against brine shrimp nauplii. In addition, minimum inhibitory concentration (MIC) was determined using serial dilution technique to determine the antibacterial potency. Results: Large zones of inhibition were observed in disc diffusion antibacterial screening against four Gram-positive bacteria (Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus and Streptococcus pyogenes) and six Gram-negative bacteria (Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, Pseudomonas aeruginosa and Salmonella typhi). The MIC values against these bacteria ranged from 8 to 64 ?g/ml. In antifungal screening, the compound showed small zones of inhibition against Aspergillus flavus, Aspergillus niger and Rhizopus aryzae. Candida albicans was resistant against the compound. In the cytotoxicity determination, LC50 of the compound against brine shrimp nauplii was 13.25 ?g/ml. Conclusions: These results suggest that the compound has good antibacterial activity against the tested bacteria, moderate cytotoxicity against brine shrimp nauplii and insignificant antifungal activity against the tested fungi.

Khan, Alam; Rahman, Moizur; Islam, M.S.

2008-01-01

202

Optical control of antibacterial activity.  

PubMed

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.  PMID:24153369

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

2013-09-15

203

Evaluation of in vitro antibacterial property of seaweeds of southeast coast of India  

Microsoft Academic Search

The in vitro antibacterial activities of seaweeds belong to Chlorophyceae (Caulerpa racemosa and Ulva lactuca), Rhodophyceae (Gracillaria folifera and Hypneme muciformis) and Phaeophyceae (Sargassum myricocystum, Sargassum tenneerimum and Padina tetrastomatica) were studied against both Gram- negative and Gram-positive pathogenic bacteria. Methanolic extracts of all seaweed extracts tested in the present study exhibited broad spectrum of antibacterial activity. Chlorophyceae members showed

M. Kandhasamy; K. D. Arunachalam

204

Oritavancin: a new promising agent in the treatment of infections due to Gram-positive pathogens.  

PubMed

Nosocomial and community-acquired infections caused by Gram-positive pathogens continue to be a challenge, mainly due to the increasing rates of resistance among Staphylococcus spp. and Enterococcus spp. Oritavancin, a new parenteral semisynthetic glycopeptide, possessing rapid bactericidal action and an antimicrobial spectrum containing all Gram-positive pathogens (streptococci, staphylococci, enterococci--vancomycin-resistant enterococci included--and Clostridia spp.) irrespective of their resistance status to the precursor molecule of vancomycin, is expected to file a new drug application by the first trimester of 2008. Once-daily dosing, good penetration into macrophages, in vitro activity against bacteria embedded in biofilms and low adverse reaction potential are further considered as oritavancin's advantages over existing drugs. While waiting for the results of supplementary Phase III studies to be announced, preliminary reports suggest the new drug will be a welcome addition to the existing antimicrobial armamentarium against Gram-positive cocci. PMID:18230056

Poulakou, Garyphallia; Giamarellou, Helen

2008-02-01

205

Antibacterial activity of cyclodextrins against Bacillus strains.  

PubMed

Growth of alkaliphilic Bacillus halodurans C-125 both on agar plates and in liquid culture was inhibited by methyl-beta-cyclodextrin (CD). Furthermore, resting cells of the strain were lysed by contact with methyl-beta-CD higher than 10 mM. alpha-CD also showed lysis activity against Bacillus and related strains. The activity was not observed with Gram-negative and Gram-positive bacteria except for Bacillus strains. Fluorescence staining and scanning electron microscopy of cells revealed that methyl-beta-CD disrupted cell membranes, and consequently, the cells were lysed. This is a novel physiological property of CDs. PMID:18665349

Zhang, Hui-Min; Li, Zhijun; Uematsu, Katsuyuki; Kobayashi, Tohru; Horikoshi, Koki

2008-07-30

206

Novel Broad-Spectrum Bis-(Imidazolinylindole) Derivatives with Potent Antibacterial Activities against Antibiotic-Resistant Strains? †  

PubMed Central

Given the limited number of structural classes of clinically available antimicrobial drugs, the discovery of antibacterials with novel chemical scaffolds is an important strategy in the development of effective therapeutics for both naturally occurring and engineered resistant strains of pathogenic bacteria. In this study, several diarylamidine derivatives were evaluated for their ability to protect macrophages from cell death following infection with Bacillus anthracis, a gram-positive spore-forming bacterium. Four bis-(imidazolinylindole) compounds were identified with potent antibacterial activity as measured by the protection of macrophages and by the inhibition of bacterial growth in vitro. These compounds were effective against a broad range of gram-positive and gram-negative bacterial species, including several antibiotic-resistant strains. Minor structural variations among the four compounds correlated with differences in their effects on bacterial macromolecular synthesis and mechanisms of resistance. In vivo studies revealed protection by two of the compounds of mice lethally infected with B. anthracis, Staphylococcus aureus, or Yersinia pestis. Taken together, these results indicate that the bis-(imidazolinylindole) compounds represent a new chemotype for the development of therapeutics for both gram-positive and gram-negative bacterial species as well as against antibiotic-resistant infections.

Panchal, Rekha G.; Ulrich, Ricky L.; Lane, Douglas; Butler, Michelle M.; Houseweart, Chad; Opperman, Timothy; Williams, John D.; Peet, Norton P.; Moir, Donald T.; Nguyen, Tam; Gussio, Rick; Bowlin, Terry; Bavari, Sina

2009-01-01

207

Preparation and antibacterial activity of chitosan nanoparticles  

Microsoft Academic Search

Chitosan nanoparticles, such as those prepared in this study, may exhibit potential antibacterial activity as their unique character. The purpose of this study was to evaluate the in vitro antibacterial activity of chitosan nanoparticles and copper-loaded nanoparticles against various microorganisms. Chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. Copper ions were adsorbed onto the

Lifeng Qi; Zirong Xu; Xia Jiang; Caihong Hu; Xiangfei Zou

2004-01-01

208

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

209

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

210

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

211

Discovery of 1,4-dihydroxy-2-naphthoate [corrected] prenyltransferase inhibitors: new drug leads for multidrug-resistant gram-positive pathogens.  

PubMed

Since utilization of menaquinone in the electron transport system is a characteristic of Gram-positive organisms, the 1,4-dihydroxy-2-naphthoate prenyltransferase (MenA) inhibitors 1a and 2a act as selective antibacterial agents against organisms such as methicillin-resistant Stapylococcus aureus (MRSA), Staphylococcus epidermidis (MRSE), and Mycobacterium spp. Growth of drug-resistant Gram-positive organisms was sensitive to the MenA inhibitors, indicating that menaquinone synthesis is a valid new drug target in Gram-positive organisms. PMID:17658779

Kurosu, Michio; Narayanasamy, Prabagaran; Biswas, Kallolmay; Dhiman, Rakesh; Crick, Dean C

2007-07-21

212

A novel and efficient one step synthesis of 2-amino-5-cyano-6-hydroxy-4-aryl pyrimidines and their anti-bacterial activity.  

PubMed

The first simple and efficient approach towards one step synthesis of 2-amino-5-cyano-6-hydroxy-4-aryl pyrimidines has been developed by three component condensation of aromatic aldehydes, ethyl cyanoacetate and guanidine hydrochloride in alkaline ethanol. The synthesized compounds evaluated for their anti-bacterial activity against gram-positive and gram-negative bacteria. The some of the compounds showed excellent zone of inhibition against tested bacteria. PMID:19036478

Deshmukh, M B; Salunkhe, S M; Patil, D R; Anbhule, P V

2008-10-26

213

Antibacterial activity in bovine lactoferrin-derived peptides.  

PubMed Central

Several peptides sharing high sequence homology with lactoferricin B (Lf-cin B) were generated from bovine lactoferrin (Lf) with recombinant chymosin. Two peptides were copurified, one identical to Lf-cin B and another differing from Lf-cin B by the inclusion of a C-terminal alanine (lactoferricin). Two other peptides were copurified from chymosin-hydrolyzed Lf, one differing from Lf-cin B by the inclusion of C-terminal alanyl-leucine and the other being a heterodimer linked by a disulfide bond. These peptides were isolated in a single step from chymosin-hydrolyzed Lf by membrane ion-exchange chromatography and were purified by reverse-phase high-pressure liquid chromatography (HPLC). They were characterized by N-terminal Edman sequencing, mass spectrometry, and antibacterial activity determination. Pure lactoferricin, prepared from pepsin-hydrolyzed Lf, was purified by standard chromatography techniques. This peptide was analyzed against a number of gram-positive and gram-negative bacteria before and after reduction of its disulfide bond or cleavage after its single methionine residue and was found to inhibit the growth of all the test bacteria at a concentration of 8 microM or less. Subfragments of lactoferricin were isolated from reduced and cleaved peptide by reverse-phase HPLC. Subfragment 1 (residues 1 to 10) was active against most of the test microorganisms at concentrations of 10 to 50 microM. Subfragment 2 (residues 11 to 26) was active against only a few microorganisms at concentrations up to 100 microM. These antibacterial studies indicate that the activity of lactoferricin is mainly, but not wholly, due to its N-terminal region.

Hoek, K S; Milne, J M; Grieve, P A; Dionysius, D A; Smith, R

1997-01-01

214

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

215

Synthesis of N-halamine-functionalized silica-polymer core-shell nanoparticles and their enhanced antibacterial activity  

NASA Astrophysics Data System (ADS)

N-halamine-functionalized silica-polymer core-shell nanoparticles with enhanced antibacterial activity were synthesized through the encapsulation of silica nanoparticles as support with polymeric N-halamine. The as-synthesized nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive x-ray spectrometry (EDX), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR). These N-halamine-functionalized silica-polymer core-shell nanoparticles displayed powerful antibacterial performance against both Gram-positive bacteria and Gram-negative bacteria, and their antibacterial activities have been greatly improved compared with their bulk counterparts. Therefore, these N-halamine-functionalized silica-polymer core-shell nanoparticles have the potential for various significant applications such as in medical devices, healthcare products, water purification systems, hospitals, dental office equipment, food packaging, food storage, household sanitation, etc.

Dong, Alideertu; Huang, Jinfeng; Lan, Shi; Wang, Tao; Xiao, Linghan; Wang, Weiwei; Zhao, Tianyi; Zheng, Xin; Liu, Fengqi; Gao, Ge; Chen, Yuxin

2011-07-01

216

Preservation of viability and antibacterial activity of Lactobacillus spp. in calcium alginate beads.  

PubMed

The objective of the study was to produce calcium alginate beads able to deliver Lactobacillus spp. (Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus bulgaricus and Lactobacillus lactis) with preserved viability and antibacterial activity. Four types of beads, containing entrapped (E), surface and entrapped (ES), surface (S) and concentrated surface and entrapped lactobacilli (C(ES)) were prepared and physically characterized. The antibacterial activity of lactobacilli cultures before and after immobilization, freeze-drying and throughout storage was studied in relationship to the viable number of lactobacilli. Multi-resistant clinical isolates (methicillin-resistant Staphylococcus aureus, vancomycine-resistant Enterococcus faecalis, VIM-2-metalo-?-lactamase producing Pseudomonas aeruginosa and CTX-M-15-?-lactamase producing strains: Escherichia coli and Klebsiella pneumoniae) were used as indicator strains. Alginate beads in which lactobacilli proliferated to the beads surface (ES and C(ES)) differed significantly from the other types of beads in their physicochemical properties, showing smoother surface morphology, more spherical shape, bigger weight, lower calcium content, density and crushing force. Lactobacilli cultures, at high cell concentrations (10(8)cfu/ml) were active against both Gram-positive and negative multi-resistant bacteria. Beads containing both entrapped and surface lactobacilli (ES) resulted in viability and antibacterial activity most similar to non-processed lactobacilli cultures. The viability and antibacterial activity of the immobilized lactobacilli remained stable after 6 months storage. PMID:20800681

Brachkova, Mariya I; Duarte, Maria A; Pinto, João F

2010-08-26

217

Aerobic Respiration in the Gram-Positive Bacteria  

Microsoft Academic Search

The group of Gram-positive bacteria is a major phylum of prokaryotes, including several typical saprophytic aerobes. Their\\u000a respiratory chains are apparently similar to those of eukaryotic mitochondria, but in several points are different from them.\\u000a The respiratory chain of Gram-positives, like many bacteria, contains branched electron transfer pathways, usually 1-3 heme-Cu\\u000a oxidases, but SoxB-type cytochrome c oxidases (cytochrome b(a\\/o)3) are

Nobhuito Sone; Cecilia Hagerhall; Junshi Sakamoto

218

Cellular reprogramming by gram-positive bacterial components: a review.  

PubMed

LPS tolerance has been the focus of extensive scientific and clinical research over the last several decades in an attempt to elucidate the sequence of changes that occur at a molecular level in tolerized cells. Tolerance to components of gram-positive bacterial cell walls such as bacterial lipoprotein and lipoteichoic acid is a much lesser studied, although equally important, phenomenon. This review will focus on cellular reprogramming by gram-positive bacterial components and examines the alterations in cell surface receptor expression, changes in intracellular signaling, gene expression and cytokine production, and the phenomenon of cross-tolerance. PMID:16885502

Buckley, Julliette M; Wang, Jiang Huai; Redmond, H Paul

2006-08-02

219

Mode of action of modified and unmodified bacteriocins from Gram-positive bacteria  

Microsoft Academic Search

The antibiotic activity of bacteriocins from Gram-positive bacteria, whether they are modified (class I bacteriocins, lantibiotics) or unmodified (class II), is based on interaction with the bacterial membrane. However, recent work has demonstrated that for many bacteriocins, generalised membrane disruption models as elaborated for amphiphilic peptides (e.g. tyriodal pore or carpet model) cannot adequately describe the bactericidal action. Rather, specific

Yann Héchard; Hans-Georg Sahl

2002-01-01

220

Determination of the total charge in the cell walls of Gram-positive bacteria  

Microsoft Academic Search

The charge in the bacterial wall originates from the dissociation of acidic groups such as carboxyl, phosphate and amino groups. The degree of dissociation of these chargeable groups is a function of the pH and the activity of the surrounding electrolyte solution. In this study the cell wall charge density of Gram-positive bacterial strains, including four coryneforms and a Bacillus

Albert van der Wal; Willem Norde; Alexander J. B. Zehnder; Johannes Lyklema

1997-01-01

221

Efflux-Mediated Resistance to Fluoroquinolones in Gram-Positive Bacteria and the Mycobacteria  

Microsoft Academic Search

The fluoroquinolone (FQ) group of antimicrobial agents is increasingly popular in the treatment of a variety of gram- negative infections, against which they are often highly effec- tive. FQs are traditionally less active against gram-positive pathogens, although they are clinically useful against Myco- plasma pneumonia and have been employed in the treatment of drug-resistant mycobacterial infections (5), as well as

KEITH POOLE

2000-01-01

222

Effect of seasonality on chemical composition and antibacterial and anticandida activities of Argentine propolis. Design of a topical formulation.  

PubMed

The effect of seasonality on Argentine propolis collected during one year on its phenolic and flavonoid content and on the growth of Gram-positive and Gram-negative antibiotic resistant bacteria and Candida species was evaluated. Extracts of propolis samples collected in the summer and spring showed higher phenolic and flavonoid contents than the samples collected in other seasons (5.86 to 6.06 mg GAE/mL and 3.77 to 4.23 mg QE/mL, respectively). The propolis collected in summer and autumn showed higher antibacterial activity (30 microg/mL) than the other samples (MIC values between 30 and 120 microg/mL). No antibacterial activity was detected against Gram-negative bacteria. Also, these extracts were able to inhibit the development of five Candida species, with MFC values of 15-120 microg/mL. Pharmaceutical formulations containing the more active propolis extract were prepared. The hydrogel of acrylic acid polymer containing summer propolis extract as an antimicrobial agent showed microbiological, physical and functional stability during storage for 180 days. The pharmaceutical preparation, as well as the propolis extracts, was active against Candida sp. and antibiotic-multi-resistant Gram-positive bacteria. These results reveal that propolis samples collected by scraping in four seasons, especially in summer in Calingasta, San Juan, Argentina, can be used to obtain tinctures and hydrogels with antibacterial and antimycotic potential for topical use. PMID:23156997

Isla, María Inés; Dantur, Yanina; Salas, Ana; Danert, Carolina; Zampini, Catiana; Arias, Myriam; Ordóñez, Roxana; Maldonado, Luis; Bedascarrasbure, Enrique; Nieva Moreno, María Inés

2012-10-01

223

Discovery of selective and potent inhibitors of gram-positive bacterial thymidylate kinase (TMK).  

PubMed

Thymidylate kinase (TMK) is an essential enzyme in bacterial DNA synthesis. The deoxythymidine monophosphate (dTMP) substrate binding pocket was targeted in a rational-design, structure-supported effort, yielding a unique series of antibacterial agents showing a novel, induced-fit binding mode. Lead optimization, aided by X-ray crystallography, led to picomolar inhibitors of both Streptococcus pneumoniae and Staphylococcus aureus TMK. MICs < 1 ?g/mL were achieved against methicillin-resistant S. aureus (MRSA), S. pneumoniae, and vancomycin-resistant Enterococcus (VRE). Log D adjustments yielded single diastereomers 14 (TK-666) and 46, showing a broad antibacterial spectrum against Gram-positive bacteria and excellent selectivity against the human thymidylate kinase ortholog. PMID:23043329

Martínez-Botella, Gabriel; Breen, John N; Duffy, James E S; Dumas, Jacques; Geng, Bolin; Gowers, Ian K; Green, Oluyinka M; Guler, Satenig; Hentemann, Martin F; Hernandez-Juan, Felix A; Joseph-McCarthy, Diane; Kawatkar, Sameer; Larsen, Nicholas A; Lazari, Ovadia; Loch, James T; Macritchie, Jacqueline A; McKenzie, Andrew R; Newman, Joseph V; Olivier, Nelson B; Otterson, Linda G; Owens, Andrew P; Read, Jon; Sheppard, David W; Keating, Thomas A

2012-10-24

224

Activity of nine oral agents against gram-positive and gram-negative bacteria encountered in community-acquired infections: Use of pharmacokinetic\\/pharmacodynamic breakpoints in the comparative assessment of beta-lactam and macrolide antimicrobial agents  

Microsoft Academic Search

Background: The application of pharmacokinetic (PK) and pharmacodynamic (PD) data in conjunction with minimum inhibitory concentrations (MICs) of antibacterial agents has been shown to allow for improved selection and appropriate dosing of antimicrobial agents for specific infections, increasing the likelihood of bacteriologic cure and, through this, reducing the risk for the development of resistant organisms.Objectives: This study was undertaken to

Mihaela Peric; Frederick A Browne; Michael R Jacobs; Peter C Appelbaum

2003-01-01

225

Synthesis, characterization, and antibacterial activities of novel methacrylate polymers containing norfloxacin.  

PubMed

A novel methacrylate monomer containing a quinolone moiety was synthesized and homopolymerized in N,N-dimethylformamide (DMF) by using azobisisobutyronitrile (AIBN) as an initiator. The new monomer was copolymerized with poly(ethylene glycol) methyl ether methacrylate (MPEGMA) in DMF using the same initiator. The monomer, homopolymer, and copolymer were characterized by elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), size exclusion chromatography (SEC), FTIR, (13)C NMR, and (1)H NMR. The antibacterial activities of the monomer as well as polymers were investigated against Staphylococcus aureus and Escherichia coli, which are representative of Gram-positive and Gram-negative bacteria, respectively. All compounds showed excellent antibacterial activities against these two types of bacteria. The antibacterial activities were determined using the shaking flask method, where 25 mg/mL concentrations of each compound were tested against 10(5) CFU/mL bacteria solutions. The number of viable bacteria was calculated by using the spread plate method, where 100 microL of the incubated antibacterial agent in bacteria solutions were spread on agar plates and the number of viable bacteria was counted after 24 h of incubation period at 37 degrees C. PMID:15638560

Dizman, Bekir; Elasri, Mohamed O; Mathias, Lon J

226

Function of the drosophila pattern-recognition receptor PGRP-SD in the detection of Gram-positive bacteria  

Microsoft Academic Search

The activation of an immune response requires recognition of microorganisms by host receptors. In drosophila, detection of Gram-positive bacteria is mediated by cooperation between the peptidoglycan-recognition protein-SA (PGRP-SA) and Gram-negative binding protein 1 (GNBP1) proteins. Here we show that some Gram-positive bacterial species activate an immune response in a PGRP-SA- and GNBP1-independent manner, indicating that alternative receptors exist. Consistent with

Vincent Bischoff; Cécile Vignal; Ivo G Boneca; Tatiana Michel; Jules A Hoffmann; Julien Royet

2004-01-01

227

In Vitro Antibacterial Activity of 4-Phenyl-1-(2-phenyl-allyl)pyridinium bromide: A Novel Class of Pyridinium Based Antibacterial Compounds.  

PubMed

The continuing increase in the incidence of multi drug resistant pathogenic bacteria and shortage of new antimicrobial agents are the prime driver in efforts to identify the novel antimicrobial classes. In vitro antibacterial activity of 4-phenyl-1-(2-phenylallyl) pyridinium bromide was tested against Gram positive Staphylococcus aureus, Streptococcus species, Bacillus subtilis, and Gram negative Klebsiella aerogenes and Escherichia coli using disk diffusion method. Among them S. aureus showed strong antibacterial activity (21.99 ± 0.03 mm) while E. coli showed very little activity (8.97 ± 0.06 mm) towards the compound. The MIC of 4-phenyl-1-(2-phenyl-allyl)-pyridinium bromide for 90% S. aureus was ?20 ?g/ml and was compared with phenoxymethylpenicillin, cloxacillin, erythromycin and vancomycin. When 4-phenyl-1-(2-phenyl-allyl)pyridinium bromide showed MIC at ?20 ?g/ml, all others showed MIC at ?100 ?g/ml. Strong antibacterial activity of 4-phenyl-1-(2-phenyl-allyl)pyridinium bromide against S. aureus indicates that there is a possibility to use it as an effective antibacterial agent. PMID:23450086

Jayatissa, Rasanthika Nayomi; Perera, Rohan Prasantha; Hettiarachchi, Chamari Madhu; Weerawarna, Pathum Manjula

2011-09-16

228

Antibacterial, antifungal and antileishmanial activities of indolone-N-oxide derivatives.  

PubMed

An alarming increase in microbial resistance to traditional drugs and classical pharmacophores has spurred the search for new antimicrobial compounds. Indolone-N-oxides (INODs) possess a redox pharmacophore with promising, recently established, antimalarial activities. In this study, the anti-infectious properties of a series of INODs were investigated. The antibacterial activity was evaluated against five bacterial strains Gram-positive (Staphylococcus aureus, Enterococcus hirae), Gram-negative (Pseudomonas aeruginosa, Escherichia coli) and acid-fast (Mycobacterium tuberculosis). The antifungal activity was assessed using two fungal strains (Aspergillus niger, Candida albicans). The antileishmanial activity was tested against two leishmanial strains, axenically-cultured amastigote (Leishmania infantum, Leishmania amazonensis). The pharmacological activities are discussed as a function of structural and lipophilic characteristics. The Gram-positive bacterial strain E. hirae was found to be the most sensitive strain, whereas the Gram-negative E. coli was resistant to this family of compounds. One compound (64) was more potent than nalidixic acid against E. hirae, whereas another one (52) was equipotent as clotrimazole against C. albicans. INODs were microbe -cidal rather than -static. INODs showed good antitubercular activity in the low micromolar range (similar to ciprofloxacin). In addition, INOD-antiprotozoal potencies were confirmed against the leishmania parasite. INODs showed a broad spectrum of antimicrobial activity and offer a promising anti-infectious prototype worthy of being developed. PMID:22828966

Ibrahim, Hany; Furiga, Aurelie; Najahi, Ennaji; Pigasse Hénocq, Christel; Nallet, Jean-Pierre; Roques, Christine; Aubouy, Agnes; Sauvain, Michel; Constant, Patricia; Daffé, Mamadou; Nepveu, Françoise

2012-07-25

229

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

230

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

2012-10-29

231

In Vitro and In Vivo Antibacterial Activities of S-4661, a New Carbapenem  

PubMed Central

The in vitro and in vivo antibacterial activities of S-4661, a new 1?-methylcarbapenem, were compared with those of imipenem, meropenem, biapenem, cefpirome, and ceftazidime. The activity of S-4661 against methicillin-susceptible staphylococci and streptococci was comparable to that of imipenem, with an MIC at which 90% of the strains tested were inhibited (MIC90) equal to 0.5 ?g/ml or less. S-4661 was highly active against members of the family Enterobacteriaceae, Haemophilus influenzae, and Moraxella catarrhalis, with MIC90s ranging from 0.032 to 0.5 ?g/ml. Against imipenem-resistant Pseudomonas aeruginosa, S-4661 was the most active among test agents (MIC90, 8 ?g/ml). Furthermore, S-4661 displayed a high degree of activity against many ceftazidime-, ciprofloxacin-, and gentamicin-resistant isolates of P. aeruginosa. The in vivo efficacy of S-4661 against experimentally induced infections in mice caused by gram-positive and gram-negative bacteria, including penicillin-resistant Streptococcus pneumoniae and drug-resistant P. aeruginosa, reflected its potent in vitro activity and high levels in plasma in mice. We conclude that S-4661 is a promising new carbapenem for the treatment of infections caused by gram-positive and -negative bacteria, including penicillin-resistant S. pneumoniae and drug-resistant P. aeruginosa.

Tsuji, Masakatsu; Ishii, Yoshikazu; Ohno, Akira; Miyazaki, Shuichi; Yamaguchi, Keizo

1998-01-01

232

Synthesis and antibacterial activities of novel nanocomposite films of chitosan/phosphoramide/Fe3O4 NPs.  

PubMed

New nanocomposite films of chitosan/phosphoramide/1-5% Fe3O4 NPs were prepared. The Fe3O4 NPs were synthesized as core-shell NPs with starch as a capping agent. The phosphoramide compound was synthesized from the reaction of morpholine with N-4-nitrophenyl phosphoramidic dichloride. The XRD and SEM analysis of Fe3O4 NPs, chitosan (CS), phosphoramide (Ph), CS/Ph and CS/Fe3O4 NPs films as well as the nanocomposite films 1-5 containing CS/Ph/1-5% Fe3O4 NPs were investigated and the results confirmed the formation of the desired films. The in vitro antibacterial activities were evaluated against four bacteria including two Gram-positive Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus) and two Gram-negative Escherchia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) bacteria. Results indicated greater antibacterial effects for the films against Gram-positive bacteria. In addition, nanocomposite films containing higher percent of Fe3O4 NPs displayed more antibacterial activities. PMID:23748004

Shariatinia, Zahra; Nikfar, Zahra

2013-06-05

233

Synthesis, antitumor and antibacterial activities of some novel tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivatives.  

PubMed

Two series of new tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines namely 2,3-disubstituted derivatives 3a-z and 2,4-disubstituted ones 6a-c were prepared and tested for their antitumor and antibacterial activities. The structures of the prepared compounds were confirmed by spectral and elemental analyses. Compound 3z exhibited the highest antitumor activity against breast MCF-7 with IC50 = 0.19 ?M compared to Doxorubicin (IC50 = 5.46 ?M), while 3r was the most active one against liver HEPG-2 cancer cell line with IC50 = 1.29 ?M as regard to Doxorubicin (IC50 = 7.36 ?M). Concerning the antibacterial activity, compounds 3m and 3z exerted remarkable activity against the tested bacterial species compared to Ampicillin, whereas compound 6c showed good activity against only Gram positive species. PMID:23708013

Abbas, Safinaz E; Abdel Gawad, Nagwa M; George, Riham F; Akar, Yahya A

2013-05-03

234

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

235

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

236

Antibacterial activity of garlic extract on streptomycin-resistant Staphylococcus aureus and Escherichia coli solely and in synergism with streptomycin  

PubMed Central

This study focuses the significant antibacterial activity of Garlic (Allium sativum Linn.) extract on streptomycin-resistant strains solely and in synergism with streptomycin. Gram-positive Staphylococcus aureus ATCC BAA 1026 and gram-negative Escherichia coli ATCC 10536 were made resistant to standard antibiotic streptomycin used as a control in the experiment. Zones of inhibition of different treatment groups were measured by agar-well-diffusion assay and compared with control. Statistical comparison of sole extract and streptomycin synergism with streptomycin control had proved it significant.

Palaksha, M. N.; Ahmed, Mansoor; Das, Sanjoy

2010-01-01

237

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

2012-10-04

238

Antibacterial activity of two phloroglucinols, flavaspidic acids AB and PB, from Dryopteris crassirhizoma.  

PubMed

The antimicrobial effect of solvent extracts from the rhizome of a thick-stemmed wood fern (Dryopteris crassirhizoma) was evaluated and its phloroglucinol components, flavaspidic acids PB and AB. Flavaspidic acids PB and AB were isolated from the D. crassirhizoma rhizomes by methanol extraction, followed by silica gel and Sephadex LH-20 column chromatography. The chemical structures were characterized by spectral techniques, including ESI-MS, UV, (1)H- and (13)C-NMR spectrum analysis. When the antimicrobial activity of the extracts and compounds was tested by the paper disc method, the extracts and compounds were highly active against Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus KCTC 1928 (a MRSA bacterium), Streptococcus mutans and Bacillus subtilis. The extracts and compounds were not active against fungi and chlorella. Our study revealed that the antibacterial activity of samples from D. crassirhizoma was mainly related to the flavaspidic acids. PMID:19471878

Lee, Hyang Burm; Kim, Jin Cheol; Lee, Sang Myung

2009-05-27

239

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

240

Postantibiotic Effect of Ceftaroline against Gram-Positive Organisms?  

PubMed Central

The postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects (SMEs) of ceftaroline, a novel injectable cephalosporin, were determined for 15 gram-positive organisms. The pneumococcal, staphylococcal, and enterococcal PAEs were 0.8 to 1.8 h, 0.7 to 2.2 h, and 0.2 to 1.1 h, respectively. The corresponding PA-SMEs (0.4 times the MIC) were 2.5 to 6.7 h, 2.9 to >0.0 h, and 7.9 to >10.3 h, respectively. The PA-SMEs were longer than the PAEs, suggesting that sub-MIC levels extend the PAE of ceftaroline against gram-positive cocci.

Pankuch, G. A.; Appelbaum, P. C.

2009-01-01

241

Global control of sugar metabolism: a Gram-positive solution  

Microsoft Academic Search

Bacteria utilise carbon sources in a strictly controlled hierarchical manner for which they have developed global control mechanisms that govern and coordinate carbon source-specific regulation. This is achieved via carbon catabolite repression (CCR), which is the result of global transcriptional control and inducer exclusion. A common mechanism for transcriptional control has evolved within the group of low-GC Gram-positive bacteria, including

Fritz Titgemeyer; Wolfgang Hillen

2002-01-01

242

Infections due to antibiotic-resistant gram-positive cocci  

Microsoft Academic Search

Summary  Gram-positive cocci are becoming increasingly resistant to traditionally used antimicrobial agents.Staphylococcus aureus, coagulase-negative staphylococci, the enterococcus, andStreptococcus pneumoniae are the most commonly encountered of such pathogens in clinical practice. Clinicians should be keenly aware of the usual\\u000a types of infections that are caused by these organisms and the importance of documenting susceptibilities of infecting strains.\\u000a The basic mechanisms of resistance

Gregory M. Caputo; Mary Singer; Scott White; Michael R. Weitekamp

1993-01-01

243

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

244

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

245

Induction, selection and antibacterial activity of the antibacterial peptides from lepidopteran insect cultured cell lines  

Microsoft Academic Search

We induced 3 cell lines that were in vitro cultured from Lepidoptera with heat inactivated Escherichia coli DH5? to stimulate the antibacterial peptide followed by antibacterial activity assay, induction dynamic research and Tricine sodium\\u000a dodecyl sulfate-polyacrylamide gel electrophoresis (Tricine SDS-PAGE) experiment. The antibacterial activity of the induced\\u000a BTI-Tn-5B1 cell line was the highest, and the antibacterial activity increased gradually to

Rong Peng; Zhong Yang; Kaiyu Liu; Hanchao Yao; Hong Yang; Yanfang Cui; Huazhu Hong

2008-01-01

246

Essential oil analysis and antibacterial activity of Rosmarinus tournefortii from Algeria.  

PubMed

The volatile compounds obtained by hydrodistillation of the aerial parts of Rosmarinus tournefortii De Noé. growing wild in the occidental region of Algeria were analyzed by GC/MS. Thirty-six compounds were characterized representing 95.6% of the essential oil, with camphor (37.6%), 1,8-cineole (10.0%), p-cymene-7-ol (7.8%), and borneol (5.4%) as the major components. The antimicrobial activity was evaluated against three pathogenic bacteria: Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus). The minimum inhibitory concentration (MIC; mg/mL) was determined by sub-culture on Muller Hinton agar plates. The essential oil exhibited strong antibacterial activity against E. coli and P. aeruginosa, and was also active against Staphylococcus aureus. PMID:22164796

Bendeddouche, Mansouria Souria; Benhassaini, Hachemi; Hazem, Zouaoui; Romane, Abderrahmane

2011-10-01

247

Antibacterial activity in four marine crustacean decapods.  

PubMed

A search for antibacterial activity in different body-parts of Pandalus borealis (northern shrimp), Pagurus bernhardus (hermit crab), Hyas araneus (spider crab) and Paralithodes camtschatica (king crab) was conducted. Dried samples were extracted with 60% (v/v) acetonitrile, containing 0.1% (v/v) trifluoroacetic acid, and further extracted and concentrated on C18 cartridges. Eluates from the solid phase extraction were tested for antibacterial, lysozyme and haemolytic activity. Antibacterial activity against Escherichia coli, Vibrio anguillarum, Corynebacterium glutamicum and Staphylococcus aureus was detected in extracts from several tissues in all species tested, but mainly in the haemolymph and haemocyte extracts. V. anguillarum and C. glutamicum were generally the most sensitive micro-organisms. In P. borealis and P. bernhardus most of the active fractions were not affected by proteinase K treatment, while in H. araneus and P. camtschatica most fractions were sensitive to proteinase K treatment, indicating antibacterial factors of proteinaceous nature. In P. bernhardus the active fractions were generally heat labile, whereas in H. araneus the activities were resistant to heat. Differences between active extracts regarding hydrophobicity and sensitivity for heat and proteinase K treatment indicate that several compounds are responsible for the antibacterial activities detected. Lysozyme-like activity could be detected in some fractions and haemolytic activity against human red blood cells could be detected in haemolymph/haemocyte and exoskeleton extracts from all species tested. PMID:12194450

Haug, Tor; Kjuul, Anita K; Stensvåg, Klara; Sandsdalen, Erling; Styrvold, Olaf B

2002-05-01

248

Actinomycetes from Moroccan habitats: isolation and screening for cytotoxic activities  

Microsoft Academic Search

In our screening for actinomycetes showing cytotoxic activities, 8 samples were collected from various Moroccan habitats,\\u000a 136 isolates were tested for their capacity to produce antibacterial compounds against gram positive bacteria. Thirty-seven\\u000a strains of these isolates were active against Gram-positive bacteria. Using the following steps of primary screening: antibacterial\\u000a activity, confrontation between the isolates and toxicity to Artemia salina; fifteen

M. Anibou; A. Chait; A. Zyad; M. Taourirt; Y. Ouhdouch; A. Benherref

2008-01-01

249

Bicephalic amphiphile architecture affects antibacterial activity.  

PubMed

A series of cationic amphiphiles, each with an aromatic core, was prepared and investigated for antimicrobial properties. The synthesized amphiphiles in this study are bicephalic (double-headed) in that they each possess two trimethylammonium head groups and a single linear alkoxy tail. Minimum inhibitory and minimum bactericidal concentrations of these amphiphiles were in the low micromolar range. Antimicrobial activities are highly sensitive to the chain length of the hydrophobic region, and modestly reliant on the relative positioning of the head groups on the aromatic core. These trends were more pronounced in time kill assays, wherein longer chain compounds required significantly shorter times to completely kill bacteria. Microscopy suggested that the mode of cell death was lysis. Strong inhibition was observed with both biscationic compounds and monocationic comparisons against Gram-positive bacteria; only biscationic amphiphiles maintained good activity versus the Gram-negative bacteria tested. These observations provide direction for future antimicrobial structural investigations. PMID:21794958

LaDow, Jade E; Warnock, David C; Hamill, Kristina M; Simmons, Kaitlin L; Davis, Robert W; Schwantes, Christian R; Flaherty, Devon C; Willcox, Jon A L; Wilson-Henjum, Kelsey; Caran, Kevin L; Minbiole, Kevin P C; Seifert, Kyle

2011-06-25

250

A new pentacyclic triterpene with potent antibacterial activity from Limnophila indica Linn. (Druce).  

PubMed

A new pentacyclic triterpenoid constituent, characterized as 3-oxo-olean-12(13),18(19)-dien-29?-carboxylic acid (1) on the basis of detailed spectral studies, was isolated from the aerial parts and roots of Limnophila indica (Scrophulariaceae). Compound 1 exhibited considerable antibacterial activity against three Gram-positive bacteria viz. Bacillus subtilis, Staphylococcus aureus and Listeria monocytogenes (MICs within a range of 25-30?g/ml) and moderate activity against four Gram-negative bacteria Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and Pantoea ananatis (MICs within a range of 30-100?g/ml). The plant pathogenic bacterium P. ananatis and human pathogenic S. typhimurium responded at comparatively higher concentrations of the compound 1, which were 75 and 100?g/ml respectively. The compound inhibited the growth of Gram-positive B. subtilis and Gram-negative P. aeruginosa completely with a clear bactericidal mode of action at their MIC values. The compound upon treatment on both B. subtilis and P. aeruginosa released substantial amount of nucleic acid in the external medium and also effected the change of morphology towards pleomorphicity, thereby indicating its probable action on cell membrane. Furthermore, the triterpenoid 1 was found not to inhibit a probiotic lactic acid bacterium Lactococcus lactis subsp. lactis LABW4 under in vitro condition and to possess no toxicity in Swiss albino mice. PMID:23876368

Brahmachari, Goutam; Mandal, Narayan C; Roy, Rajiv; Ghosh, Ranjan; Barman, Soma; Sarkar, Sajal; Jash, Shyamal K; Mondal, Sadhan

2013-07-20

251

Antifungal and antibacterial activities of diarylamidine derivatives.  

PubMed Central

The antifungal and antibacterial properties of a series of 70 diarylamidine derivatives were evaluated. Several of these compounds exhibited considerable antimicrobial potency. A survey of the structure-activity relationship demonstrated that minor structural variations resulted in significant changes of antimicrobial activity. In general, the structural features required for antifungal activity coincided with those required for antibacterial activity. Both the antifungal and the antibacterial properties of the diarylamidines depended on the presence and the positions, of both amidino groups, on the nature of the central bridge connecting the two aryl moieties, and on the nature of these aryl residues (preferably indole). The most active compound was evaluated for its activity against Candida albicans infection in mice.

Anne, J; De Clercq, E; Eyssen, H; Dann, O

1980-01-01

252

Essential oil composition and antibacterial activity of Anthemis mixta and A. tomentosa (Asteraceae).  

PubMed

In the present study the chemical composition of the essential oils from aerial parts and roots of Anthemis mixta L. and A. tomentosa L. was evaluated by GC and GC-MS, and their antibacterial activity tested against ten bacterial species. Hexadecanoic acid (15.2%) was recognized as the main constituent ofA. mixta, together with tau-cadinol (6.7%), while in both aerial parts and roots of A. tomentosa nonacosane (21.9% and 20.7%), heptacosane (8.1% and 6.0%), hexadecanoic acid (8.1% and 27.1%) and hexahydrofarnesylacetone (6.8% and 5.5%) prevailed. The oils from aerial parts of both species showed a good activity against Gram-positive bacteria. These results suggest that the plants could be potentially used in food manufacture and cosmetology as preservative agents or in medicine as new antibiotics. PMID:23157016

Formisano, Carmen; Rigano, Daniela; Senatore, Felice; Raimondo, Francesco Maria; Maggio, Antonella; Bruno, Maurizio

2012-10-01

253

Laboratory Evaluation of BL-S786, a Cephalosporin with Broad-Spectrum Antibacterial Activity  

PubMed Central

Biological and physicochemical properties of BL-S786 were compared with those of cephalothin, cephaloridine, and cefazolin. With few exceptions, BL-S786 was more active than the reference compounds against major gram-negative pathogenic species and its antibacterial spectrum was broader than that of cephalosporins currently available for clinical use. Although BL-S786 was generally less active than the control cephalosporins against gram-positive pathogens, it inhibited their growth at concentrations that should readily be achieved in humans after standard parenteral dosage. Streptococcus faecalis, a species relatively unsusceptible to cephalosporins in general, was an exception. BL-S786 was an effective bactericidal agent for strains of various gram-negative organisms. After intramuscular administration to mice, BL-S786 achieved high concentrations in blood, and its biological half-life was longer than that of the other three cephalosporins.

Leitner, F.; Misiek, M.; Pursiano, T. A.; Buck, R. E.; Chisholm, D. R.; DeRegis, R. G.; Tsai, Y. H.; Price, K. E.

1976-01-01

254

CtsR Regulation in mcsAB-Deficient Gram-Positive Bacteria  

PubMed Central

CtsR is an important repressor that modulates the transcription of class III stress genes in Gram-positive bacteria. In Bacillus subtilis, a model Gram-positive organism, the DNA binding activity of CtsR is regulated by McsAB-mediated phosphorylation of the protein where phosphorylated CtsR is a substrate for degradation by the ClpCP complex. Surprisingly, the mcsAB genes are absent from many Gram-positive bacteria, including streptococci; therefore, how CtsR activity is modulated in those bacteria remains unknown. Here we show that the posttranslational modulation of CtsR activity is different in Streptococcus mutans, a dental pathogen. We observed that of all of the Clp-related proteins, only ClpL is involved in the degradation of CtsR. Neither ClpP nor ClpC had any effect on the degradation of CtsR. We also found that phosphorylation of CtsR on a conserved arginine residue within the winged helix-turn-helix domain is necessary for modulation of the repressor activity of CtsR, as demonstrated by both in vitro and in vivo assays. We speculate that CtsR is regulated posttranslationally by a different mechanism in S. mutans and possibly in other streptococci.

Tao, Liang; Chattoraj, Partho

2012-01-01

255

Activity of antibacterial impregnated central venous catheters against Klebsiella pneumoniae  

Microsoft Academic Search

Objective: Antibiotically coated or impregnated catheters are effective in eliminating gram-positive bacteria from their surfaces. However, their activity against gram-negative bacteria is not well known. The aim of this study was to evaluate and compare the adherence, persistence and colonization of Klebsiella pneumoniae on catheter surfaces and also to assess bacteriostatic and bactericidal levels. Design: Randomized, controlled, laboratory study. Setting:

Kaya Yorganci; Candace Krepel; John A. Weigelt; Charles E. Edmiston

2002-01-01

256

Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria  

Microsoft Academic Search

\\u000a The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become\\u000a an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and\\u000a human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic\\u000a host systems makes them attractive candidates for

Lucila Saavedra; Fernando Sesma

2011-01-01

257

[Antibacterial activity of nitazole and its use in combined treatment of appendicular peritonitis in children].  

PubMed

The experimental-clinical investigations have demonstrated the high effectiveness of the native preparation Nitazole against the Gram-negative non-spore-forming anaerobic bacteria, Gram-positive anaerobic cocci, spore-forming Clostridium, certain facultative anaerobes. This permits to recommend it for the use as an antibacterial preparation for the treatment of peritonitis in children. PMID:2398654

Topuzov, V S; Tsyganenko, A Ia; Kalinichenko, N F; Vasil'chenko, V N; Kovalenko, N I; Davidenko, V B; Gabysheva, L S; Liapunov, N A; Starobinets, Z G; Osolodchenko, T P

1990-01-01

258

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

259

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

2013-01-17

260

Composition and antibacterial activity of the essential oils from Zanthoxylum rhoifolium.  

PubMed

The essential oils from the aerial parts of leaves, fruits and flowers of Zanthoxylum rhoifolium of Southern Brazil (Rio Grande do Sul), were analysed by GC, GC/MS, and chiral phase gas chromatography (CPGC). Forty-eight compounds were identified from the essential oils. The major constituents of the essential oil of the leaves were germacrene D (34 %) and bicyclogermacrene (23 %) and of the fruits, menth-2-en-1-ol (46.2 %), beta-myrcene (30.2 %), (-)-linalool (15 %) and (-)-alpha-terpineol (8.45 %). beta-Myrcene (65 %) and menth-2-en-1-ol (5.4 %) dominate the essential oil of the flowers. The oils of the leaves and fruits were bioactive with antibacterial activity against Staphylococcus aureus (Gram positive), and Klebsiella pneumoniae and Salmonella setubal bacteria (Gram negative) microorganisms, while the essential oil of the flowers was inactive. PMID:14531032

de Abreu Gonzaga, Wellington; Weber, Andréia Denise; Giacomelli, Sandro Rogério; Simionatto, Euclésio; Dalcol, Ionara Irion; Dessoy, Emilia Carolina Machado; Morel, Ademir Farias

2003-08-01

261

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

262

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

2013-01-12

263

Antibacterial Activity of Dental Restorative Materials  

Microsoft Academic Search

Twenty-one commercial dental restorative materials, aged under various conditions, were checked on two different culture mediums for their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Lactobacillus plantarum, a cariogenic streptococcus, and mixed bacteria from the mouth. The duration of bacteriostatic activity was decreased rapidly by leaching in water. Of the three acrylics checked for ability to prevent in vitro carieslike

David M. Updegraff; Robert W. H. Chang; Richard W. Joos

1971-01-01

264

Gram-positive bacteria: an overview and summary of session.  

PubMed

The more pathogenic gram-positive bacteria present a complex array of surface structures to the human or animal host. The cell wall of Staphylococcus aureus has a pattern of surface proteins; the predominant one is protein A. Virulent S. aureus strains may also produce polysaccharide capsules in vivo that impede opsonization and phagocytosis in the absence of anticapsular antibody. Coagulase-negative staphylococci commonly elaborate an exopolysaccharide slime that may promote adherence to plastic surfaces and interfere with host responses. Structure-function relationships for some antiphagocytic M proteins of group A streptococci are now well understood, and recombinant techniques offer the prospect of multivalent vaccines. The best known surface protein of group B streptococci is the c (Ibc) protein, which stimulates protective antibody in animals and may be an important virulence factor. Monoclonal antibodies to types Ib, II, and III group B streptococci have also confirmed the presence of multiple immunodeterminants on these antiphagocytic polysaccharides. A protein on the surface of pneumococci has been shown to induce protective antibody and to enhance pneumococcal virulence in mice, suggesting a potential alternative or adjunct to pneumococcal polysaccharide vaccines. Listeria also possess a variety of cell surface structures important in pathogenesis. Surface components are, therefore, critical determinants of the interaction of gram-positive bacteria with the host. PMID:3055202

Anthony, B F; Hill, H R

265

Antibacterial, antifungal and cytotoxic activities of extracts from fish epidermis and epidermal mucus.  

PubMed

Annual discards from the world fisheries are estimated to be approximately 20 million metric tonnes (25%) per year. The main objective of this work is to increase the utilisation of by-products (notably skin) from fish species in order to isolate new biologically active compounds. This study presents the results of a screening program for antifungal, antibacterial and cytotoxic activities in epidermal mucus and epidermis extracts of thirteen fish species that are commonly caught in North Atlantic waters and generate an important amount of fish waste. Antimicrobial assays used five Gram-positive bacteria five Gram-negative bacteria and five fungi. Of the 78 extracts tested, 15 showed antibacterial and/or antifungal activities. None of the aqueous fractions were active. One third of the active extracts were ethanolic fractions and three fourth of extracts were dichloromethane fractions. One third of the active fractions were of epidermal origin and the remaining came from mucus fractions. The high levels of inhibitory activity and no apparent toxicity against mouse fibroblasts of extracts of Pollachius virens (CH(3)CH(2)OH/epidermis), Labrus bergylta (CH(2)Cl(2)/mucus), Platichthys flesus (CH(3)CH(2)OH/mucus), Solea solea (CH(2)Cl(2)/mucus) and Scophtalamus rhombus (CH(2)Cl(2)/mucus) suggest they may have potential as novel active therapeutic agents. PMID:12385701

Hellio, Claire; Pons, Anne Marie; Beaupoil, Claude; Bourgougnon, Nathalie; Gal, Yves Le

2002-09-01

266

Effect of ester to amide or N-methylamide substitution on bacterial membrane depolarization and antibacterial activity of novel cyclic lipopeptides.  

PubMed

Cyclic lipopeptides derived from the fusaricidin/LI-F family of naturally occurring antibiotics represent particularly attractive candidates for the development of new antibacterial agents. In comparison with natural products, these derivatives may offer better stability under physiologically relevant conditions and lower nonspecific toxicity, while preserving their antibacterial activity. In this study we assessed the ability of cyclic lipodepsipeptide 1 and its analogues--amide 2, N-methylamide 3, and linear peptide 4--to interact with the cytoplasmic membranes of selected Gram-positive bacteria. We also investigated their bacteriostatic/bactericidal modes of action and in?vivo potency by using a Galleria mellonella model of MRSA infection. Cyclic lipopeptides 1 and 2 depolarize the cytoplasmic membranes of Gram-positive bacteria in a concentration-dependent manner. The degree of membrane depolarization was influenced by the structural and physical properties of 1 and 2, with the more flexible and hydrophobic peptide 1 being most efficient. However, membrane depolarization does not correlate with bacterial cell lethality, suggesting that membrane-targeting activity is not the main mode of action for this class of antibacterial peptides. Conversely, substitution of the depsipeptide bond in 1 with an N-methylamide bond in 3, or its hydrolysis to peptide 4, lead to a complete loss of antibacterial activity and indicate that the conformation of cyclic lipopeptides plays a role in their antibacterial activities. Cyclic lipopeptides 1 and 2 are also capable of improving the survival of G.?mellonella larvae infected with MRSA at varying efficiencies, reflecting their in?vitro activities. Gaining more insight into the structure-activity relationship and mode of action of these cyclic lipopeptides may enable the development of new antibiotics of this class with improved antibacterial activity. PMID:23780744

Bionda, Nina; Fleeman, Renee M; Shaw, Lindsey N; Cudic, Predrag

2013-06-18

267

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

268

Ambuic Acid Inhibits the Biosynthesis of Cyclic Peptide Quormones in Gram-Positive Bacteria ?  

PubMed Central

Quorum sensing is a cell-density-dependent regulatory system in gram-positive bacteria and is often regulated by cyclic peptides called “quormones,” which function as extracellular communication signals. With an aim to discover an antipathogenic agent targeting quorum sensing in gram-positive bacteria, we screened 153 samples of fungal butanol extracts with the guidance of the inhibition of quorum-sensing-mediated gelatinase production in Enterococcus faecalis. Following the screenings, we found that ambuic acid, a known secondary fungal metabolite, inhibited the quorum-sensing-mediated gelatinase production without influencing the growth of E. faecalis. We further demonstrated that ambuic acid targeted the biosynthesis of a cyclic peptide quormone called gelatinase biosynthesis-activating pheromone. Furthermore, ambuic acid also inhibited the biosynthesis of the cyclic peptide quormones of Staphylococcus aureus and Listeria innocua. These results suggest the potential use of ambuic acid as a lead compound of antipathogenic drugs that target the quorum-sensing-mediated virulence expression of gram-positive bacteria.

Nakayama, Jiro; Uemura, Yumi; Nishiguchi, Kenzo; Yoshimura, Norito; Igarashi, Yasuhiro; Sonomoto, Kenji

2009-01-01

269

Evaluation of antibacterial activity against Salmonella Enteritidis.  

PubMed

Salmonella enterica serovar Enteritidis is a well-known pathogenic bacterium responsible for human gastrointestinal enteritis mainly due to the consumption of eggs and egg-products. The first aim of this work was to study several virulence factors of a strain isolated from egg content: SEovo. First, bacterial growth was studied at several temperatures and cell morphology was observed by scanning electronic microscopy. These experiments showed Salmonella's ability to grow at low temperatures and to produce exoproducts. Next, Salmonella motility was observed performing swimming, twitching, and swarming tests. Results indicated a positive flagellar activity and the cell ability to differentiate and become hyperflagellated under specific conditions. Moreover, SEovo adherence and biofilm formation was carried out. All of these tests enabled us to conclude that SEovo is a potential pathogen, thus it can be used as a model to perform antibacterial experiments. The second part of the study was dedicated to the evaluation of the antibacterial activity of different molecules using several methods. The antibacterial effect of silver and copper aluminosilicates was tested by two different kinds of methods. On the one hand, the effect of these two antibacterial agents was determined using microbiological methods: viable cell count and agar-well diffusion. And on the other hand, the antibacterial activity was evaluated using CLSM and SYTO Red/SYTOX Green dyeing. CLSM allowed for the evaluation of the biocide on sessile cells, whereas the first methods did not. Results showed that adhered bacteria were more resistant than planktonic counterparts and that CLSM was a good alternative to evaluate antibacterial activity on fixed bacteria without having to carry out a removing step. PMID:21717317

Legendre, Gaëlle; Faÿ, Fabienne; Linossier, Isabelle; Vallée-Réhel, Karine

2011-06-30

270

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

271

Enhanced antibacterial activity of bimetallic gold-silver core-shell nanoparticles at low silver concentration  

NASA Astrophysics Data System (ADS)

Herein we report the development of bimetallic Au@Ag core-shell nanoparticles (NPs) where gold nanoparticles (Au NPs) served as the seeds for continuous deposition of silver atoms on its surface. The core-shell structure and morphology were examined by UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). The core-shell NPs showed antibacterial activity against both Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Enterococcus faecalis and Pediococcus acidilactici) bacteria at low concentration of silver present in the shell, with more efficacy against Gram negative bacteria. TEM and flow cytometric studies showed that the core-shell NPs attached to the bacterial surface and caused membrane damage leading to cell death. The enhanced antibacterial properties of Au@Ag core-shell NPs was possibly due to the more active silver atoms in the shell surrounding gold core due to high surface free energy of the surface Ag atoms owing to shell thinness in the bimetallic NP structure.Herein we report the development of bimetallic Au@Ag core-shell nanoparticles (NPs) where gold nanoparticles (Au NPs) served as the seeds for continuous deposition of silver atoms on its surface. The core-shell structure and morphology were examined by UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). The core-shell NPs showed antibacterial activity against both Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Enterococcus faecalis and Pediococcus acidilactici) bacteria at low concentration of silver present in the shell, with more efficacy against Gram negative bacteria. TEM and flow cytometric studies showed that the core-shell NPs attached to the bacterial surface and caused membrane damage leading to cell death. The enhanced antibacterial properties of Au@Ag core-shell NPs was possibly due to the more active silver atoms in the shell surrounding gold core due to high surface free energy of the surface Ag atoms owing to shell thinness in the bimetallic NP structure. Electronic supplementary information (ESI) available. See DOI: 10.1039/c1nr10703h

Banerjee, Madhuchanda; Sharma, Shilpa; Chattopadhyay, Arun; Ghosh, Siddhartha Sankar

2011-12-01

272

Composition and antibacterial activity of essential oil of Lippia graveolens H.B.K. (Verbenaceae) (Composición y actividad antibacteriana del aceite esencial de Lippia graveolens H.B.K. (Verbenaceae))  

Microsoft Academic Search

The essential oil of the aerial parts of Lippia graveolens H.B.K. (Verbenaceae) was examined by GC and GC-MS. Nine constituents were identified. Carvacrol, ?-terpinyl acetate, m-cymene, thymol and ?-pinene were found to be the major components. The oil exhibited antibacterial activity against Gram- positive (Staphylococcus aureus; Staphylococcus epidermidis, Bacillus subtilis, Sarcina lutea) and Gram-negative bacteria (Shigella boydii, Vibrio cholerae No-01,

Tzasna HERNÁNDEZ; Margarita CANALES; José Guillermo AVILA; Ana Maria GARCÍA; Samuel MERAZ; Javier CABALLERO; Rafael LIRA

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

Antibacterial activity of some medicinal plant extracts  

Microsoft Academic Search

Antibacterial activity of hot aqueous and methanolic extracts prepared from six plants (Terminallia chebula, Terminallia bellerica, Phyllanthus emblica, Punica granatum, Lawsonia alba and Mikania micrantha) used in traditional folk medicines of India were screened against five pathogenic bacteria (Staphylococcus aureus MTCC 2940, Bacillus subtilis MTCC 441, Escherichia coli MTCC 739, Proteus vulgaris MTCC 426 and Enterobacter aerogenes MTCC 111). The

Anupam Ghosh; Bidus Kanti Das; Arup Roy; Biplab Mandal; Goutam Chandra

2008-01-01

275

Antibacterial, antioxidant and tyrosinase-inhibition activities of pomegranate fruit peel methanolic extract  

PubMed Central

Background This study evaluated, using in vitro assays, the antibacterial, antioxidant, and tyrosinase-inhibition activities of methanolic extracts from peels of seven commercially grown pomegranate cultivars. Methods Antibacterial activity was tested on Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia) using a microdilution method. Several potential antioxidant activities, including radical-scavenging ability (RSA), ferrous ion chelating (FIC) and ferric ion reducing antioxidant power (FRAP), were evaluated. Tyrosinase enzyme inhibition was investigated against monophenolase (tyrosine) and diphenolase (DOPA), with arbutin and kojic acid as positive controls. Furthermore, phenolic contents including total flavonoid content (TFC), gallotannin content (GTC) and total anthocyanin content (TAC) were determined using colourimetric methods. HPLC-ESI/MSn analysis of phenolic composition of methanolic extracts was also performed. Results Methanolic peel extracts showed strong broad-spectrum activity against Gram-positive and Gram-negative bacteria, with the minimum inhibitory concentrations (MIC) ranging from 0.2 to 0.78 mg/ml. At the highest concentration tested (1000 ?g/ml), radical scavenging activities were significantly higher in Arakta (83.54%), Ganesh (83.56%), and Ruby (83.34%) cultivars (P< 0.05). Dose dependent FIC and FRAP activities were exhibited by all the peel extracts. All extracts also exhibited high inhibition (>50%) against monophenolase and diphenolase activities at the highest screening concentration. The most active peel extract was the Bhagwa cultivar against monophenolase and the Arakta cultivar against diphenolase with IC50 values of 3.66 ?g/ml and 15.88 ?g/ml, respectively. High amounts of phenolic compounds were found in peel extracts with the highest and lowest total phenolic contents of 295.5 (Ganesh) and 179.3 mg/g dry extract (Molla de Elche), respectively. Catechin, epicatechin, ellagic acid and gallic acid were found in all cultivars, of which ellagic acid was the most abundant comprising of more than 50% of total phenolic compounds detected in each cultivar. Conclusions The present study showed that the tested pomegranate peels exhibited strong antibacterial, antioxidant and tyrosinase-inhibition activities. These results suggest that pomegranate fruit peel could be exploited as a potential source of natural antimicrobial and antioxidant agents as well as tyrosinase inhibitors.

2012-01-01

276

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

277

In Vitro and In Vivo Antibacterial Activities of CS-834, a New Oral Carbapenem  

PubMed Central

CS-834 is a prodrug of the carbapenem R-95867, developed by Sankyo Co., Ltd., Tokyo, Japan. To investigate the possibility that CS-834 may be the first carbapenem usable in an oral dosage form, its in vitro antibacterial activity (as R-95867) and in vivo antibacterial activity were compared with those of cefpodoxime proxetil, cefditoren pivoxil, cefdinir, ofloxacin, imipenem, and amoxicillin. R-95867 had high levels of activity against methicillin-susceptible staphylococci and streptococci, including penicillin-resistant Streptococcus pneumoniae, as well as Neisseria gonorrhoeae, Moraxella catarrhalis, the members of the family Enterobacteriaceae (with the exception of Serratia marcescens), Haemophilus influenzae, and Bordetella pertussis; for all these strains, the MICs at which 90% of tested strains are inhibited (MIC90s) were 1.0 ?g/ml or less. Against methicillin-resistant staphylococci, enterococci, Serratia marcescens, Brukholderia cepacia, Stenotrophomonas maltophilia, and Acinetobacter calcoaceticus, R-95867 showed activity comparable to or slightly less than that of imipenem, with MIC90s ranging from 2 to >128 ?g/ml. The in vivo efficacy of oral CS-834 against experimental mouse septicemia caused by gram-positive and gram-negative bacteria was better than that of comparative drugs. In murine respiratory infection models, the efficacy of CS-834 reflected not only its potent in vitro activity but also the high levels present in the lungs.

Yamaguchi, Keizo; Domon, Haruki; Miyazaki, Shuichi; Tateda, Kazuhiro; Ohno, Akira; Ishii, Kazuhiro; Matsumoto, Tetsuya; Furuya, Nobuhiko

1998-01-01

278

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

2013-08-26

279

[Antibacterial action of the polymeric antiseptic catapol].  

PubMed

Activity of a polymer derivative of catamine AB, the antiseptic catapol, against gram positive and gram negative bacteria was studied. The effect of catapol on structural components of bacterial cells and permeability of bacterial cell membranes was investigated. The possibility of varying the susceptibility of bacteria to catapol and the effect of catapol on bacteria susceptible to antibiotics were evaluated. It was shown that by its in vitro antibacterial activity, catapol does not significantly differ from catamine AB. PMID:7826176

Zaikina, N A; Iagodkina, M V; Solovki?, M V

1994-04-01

280

Antibacterial and antimycotic activities of Slovenian honeys.  

PubMed

In the present study, Slovenian honey samples produced from different floral sources are evaluated for their antibacterial and antifungal properties. The peroxide contribution to antibacterial activity is also determined. Minimum inhibitory concentration (MIC) of the honeys was assessed against four bacterial species (Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa and Staphylococcus aureus) and against eight fungal species (Aspergillus niger, Aureobasidium pullulans, Candida albicans, Candida parapsilosis, Candida tropicalis, Cladosporium cladosporioides, Penicillium chrysogenum and Rhodotorula mucilaginosa). Honey at concentrations between 1% and 50% (v/v) were tested. Although all of the bacterial species were inhibited by the different honey samples, the chestnut and pasture honeys showed the highest antibacterial activities. The antifungal activities were concentration-dependent, with five (Aureobasidium pullulans, Candida parapsilosis, Candida tropicalis, Cladosporium cladosporioides, Rhodotorula mucilaginosa) inhibited only at honey concentrations greater than 50%. The fungi Aspergillus niger, Candida albicans and Penicillium chrysogenum were not inhibited by any of the tested honeys, even at the highest concentrations. The lowest MICs seen were 2.5% (v/v) for the chestnut, fir and forest honeys against Staphylococcus aureus, and 10.0% (v/v) for the chestnut and pasture honeys against Cladosporium cladosporioides. The non-peroxide action of chestnut honey was tested against Escherichia coli. The MIC of the catalase-treated chestnut honey was 50% (v/v). The antibacterial effect of Slovenian honeys is mostly due to peroxide action. These data support the concept that Slovenian honeys are effective antibacterials and antifungals, and can thus be applied for medicinal purposes. PMID:23304790

Kuncic, M Kralj; Jaklic, D; Lapanje, A; Gunde-Cimerman, N

2012-01-01

281

Synthesis, antibacterial and antitubercular activities of some 7-[4-(5-amino-[1,3,4]thiadiazole-2-sulfonyl)-piperazin-1-yl] fluoroquinolonic derivatives  

Microsoft Academic Search

In the present study, a series of 7-[4-(5-amino-1,3,4 thiadiazole-2-sulfonyl)]-1-piperazinyl fluoroquinolonic derivatives VIIa–d were synthesized in good yields and characterized by IR, 1H-NMR, 13C-NMR, FAB Mass spectral and elemental analyses. The compounds were evaluated for their preliminary in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria and selected compounds VIIa, b were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv

S. Talath; A. K. Gadad

2006-01-01

282

Thieno[2,3-d]pyrimidinedione derivatives as antibacterial agents  

PubMed Central

Several thieno[2,3-d]pyrimidinediones have been synthesized and examined for antibacterial activity against a range of Gram-positive and Gram-negative pathogens. Two compounds displayed potent activity (2–16 mg/L) against multi-drug resistant Gram-positive organisms, including methicillin, vancomycin-intermediate, and vancomycin-resistant Staphylococcus aureus (MRSA, VISA, VRSA) and vancomycin-resistant enterococci (VRE). Only one of these agents possessed moderate activity (16–32 mg/L) against Gram-negative strains. An examination of the cytotoxicity of these agents revealed that they displayed low toxicity (40–50 mg/L) against mammalian cell and very low hemolytic activity (2–7%). Taken together, these studies suggest that thieno[2,3-d]pyrimidinediones are interesting scaffolds for the development of novel Gram-positive antibacterial agents.

Dewal, Mahender B.; Wani, Amit S.; Vidaillac, Celine; Oupicky, David; Rybak, Michael J.

2012-01-01

283

Synthesis and antibacterial activities of novel 4-hydroxy-7-hydroxy- and 3-carboxycoumarin derivatives.  

PubMed

Coumarin derivatives are used as fluorescent dyes and medicines. They also have some notable physiological effects, including the acute hepatoxicity and carcinogenicity of certain aflatoxins, the anticoagulant action of dicoumarol, and the antibiotic activity of novobicin and coumerymycin A1. Because the number of drug resistant strains is increasing at present, the synthesis of new antibacterial compounds is one of the critical methods for treating infectious diseases. Therefore, a series of coumarinsubstituted derivatives, namely 4-hydroxy- and 7-hydroxycoumarins, and 3-carboxycoumarins were synthesized. 4-Hydroxycoumarin derivatives 4a-c underwent rearrangement reactions. Both 4- and 7-hydroxycoumarins were treated with activated aziridines which produced series of ring-opened products 7, 8, 10, and 11. 3-Carboxy-coumarin amide dimer derivatives 14-21 were prepared by reacting aliphatic alkylamines and alkyldiamines with PyBOP and DIEA. In this study, we use a new technique called modified micro-plate antibiotic susceptibility test method (MMAST), which is more convenient, more efficient, and more accurate than previous methods and only a small amount of the sample is required for the test. Some of the compounds were produced by reactions with acid anhydrides and demonstrated the ability to inhibit Gram-positive microorganisms. The dimer derivatives displayed lower antibacterial activities. PMID:22964501

Lin, Pen-Yuan; Yeh, Kuang-Sheng; Su, Chien-Ling; Sheu, Shiow-Yunn; Chen, Tiffany; Ou, Keng-Liang; Lin, Mei-Hsiang; Lee, Lin-Wen

2012-09-10

284

Mechanistic and physiological consequences of HPr(ser) phosphorylation on the activities of the phosphoenolpyruvate:sugar phosphotransferase system in gram-positive bacteria: studies with site-specific mutants of HPr.  

PubMed Central

The bacterial phosphotransferase system (PTS) catalyzes the transport and phosphorylation of its sugar substrates. The protein-kinase-catalyzed phosphorylation of serine 46 in the phosphocarrier protein, HPr, inhibits PTS activity, but neither the mechanism of this inhibition nor its physiological significance is known. Site-specific HPr mutants were constructed in which serine 46 was replaced by alanine (S46A), threonine (S46T), tyrosine (S46Y) or aspartate (S46D). The purified S46D protein exhibited markedly lower Vmax and higher Km values than the wild-type, S46T or S46A protein for the phosphoryl transfer reactions involving HPr(His approximately P). Interactions of HPr with the enzymes catalyzing phosphoryl transfer to and from HPr regulated the kinase-catalyzed reaction. These results establish the inhibitory effect of a negative charge at position 46 on PTS-mediated phosphoryl transfer and suggest that HPr is phosphorylated on both histidyl and seryl residues by enzymes that recognize its tertiary rather than its primary structure. In vivo studies showed that a negative charge on residue 46 of HPr strongly inhibits PTS-mediated sugar uptake, but that competition of two PTS permeases for HPr(His approximately P) is quantitatively more important to the regulation of PTS function than serine 46 phosphorylation. Images

Reizer, J; Sutrina, S L; Saier, M H; Stewart, G C; Peterkofsky, A; Reddy, P

1989-01-01

285

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

286

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

287

In Vitro Antibacterial Activities of DQ-113, a Potent Quinolone, against Clinical Isolates  

PubMed Central

The antibacterial activity of DQ-113, formerly D61-1113, was compared with those of antibacterial agents currently available. MICs at which 90% of the isolates tested are inhibited (MIC90s) of DQ-113 against clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus and methicillin-susceptible and -resistant coagulase-negative staphylococci were 0.03, 0.008, 0.03, and 0.06 ?g/ml, respectively. Moreover, DQ-113 showed the most potent activity against ofloxacin-resistant and methicillin-resistant S. aureus, with a MIC90 of 0.25?g/ml. DQ-113 inhibited the growth of all strains of Streptococcus pneumoniae, including penicillin-resistant strains, and Streptococcus pyogenes at 0.06 ?g/ml, and DQ-113 was more active than the other quinolones tested against Enterococcus faecalis and Enterococcus faecium with MIC90s of 0.25 and 2 ?g/ml, respectively. Against vancomycin-resistant enterococci, DQ-113 showed the highest activity among the reference compounds, with a MIC range from 0.25 to 2 ?g/ml. DQ-113 also showed a potent activity against Haemophilus influenzae, including ampicillin-resistant strains (MIC90, 0.015 ?g/ml), and Moraxella catarrhalis (MIC90, 0.03 ?g/ml). The activity of DQ-113 was roughly comparable to that of levofloxacin against all species of Enterobacteriaceae. The MICs of DQ-113 against ofloxacin-susceptible Pseudomonas aeruginosa ranged from 0.25 to 2 ?g/ml, which were four times higher than those of ciprofloxacin. From these results, DQ-113 showed the most potent activity against gram-positive pathogens among antibacterial agents tested.

Tanaka, Mayumi; Yamazaki, Emi; Chiba, Megumi; Yoshihara, Kiyomi; Akasaka, Takaaki; Takemura, Makoto; Sato, Kenichi

2002-01-01

288

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

2013-09-10

289

Enhanced antibacterial activity of bimetallic gold-silver core-shell nanoparticles at low silver concentration.  

PubMed

Herein we report the development of bimetallic Au@Ag core-shell nanoparticles (NPs) where gold nanoparticles (Au NPs) served as the seeds for continuous deposition of silver atoms on its surface. The core-shell structure and morphology were examined by UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). The core-shell NPs showed antibacterial activity against both gram negative (Escherichia coli and Pseudomonas aeruginosa) and gram positive (Enterococcus faecalis and Pediococcus acidilactici) bacteria at low concentration of silver present in the shell, with more efficacy against gram negative bacteria. TEM and flow cytometric studies showed that the core-shell NPs attached to the bacterial surface and caused membrane damage leading to cell death. The enhanced antibacterial properties of Au@Ag core-shell NPs was possibly due to the more active silver atoms in the shell surrounding gold core due to high surface free energy of the surface Ag atoms owing to shell thinness in the bimetallic NP structure. PMID:22057130

Banerjee, Madhuchanda; Sharma, Shilpa; Chattopadhyay, Arun; Ghosh, Siddhartha Sankar

2011-11-04

290

The crystal structure and biochemical properties of DHBPS from Streptococcus pneumoniae, a potential anti-infective target for Gram-positive bacteria.  

PubMed

The enzymes involved in riboflavin biosynthesis are considered to be potential anti-bacterial drug targets because these proteins are essential in bacterial pathogens but are absent in humans. 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) is one of the key enzymes in the biosynthesis of riboflavin. DHBPS catalyzes the conversion of ribulose-5-phosphate (Ru5P) to 3,4-Dihydroxy-2-butanone-4-phosphate (DHBP) and formate. The purified SpDHBPS enzyme, in the presence of Mg(2+) ion, catalyzed the conversion of Ru5P to DHBP at a rate of 109nmolmin(-1)mg(-1) with an apparent Km value of 181?M at 37°C. Surprisingly, our experiments first revealed that DHBPS showed activity in the presence of the trivalent metal ion, Fe(3+). Furthermore, we determined the crystal structure of DHBPS from Gram-positive bacteria, Streptococcus pneumoniae, with 2.0Å resolution. The overall architecture of SpDHBPS was similar to its homologs, which comprise one ?-sheet (five-stranded) and eight ?-helices, adopting a three-layered ?-?-? sandwich fold. Similar to the homologs, gel-filtration experiments verified that the enzyme was arranged as a dimer. Although the overall fold of DHBPS was similar, the significant structural differences between the species at the active site region may be utilized to develop antibacterial agents that are species-specific. PMID:23954596

Li, Jin; Hua, Zhou; Miao, Luo; Jian, Tang; Wei, Yang; Shasha, Zhao; Shaocheng, Zhang; Zhen, Guo; Hongpeng, Zhang; Ailong, Huang; Deqiang, Wang

2013-08-15

291

Gram-positive marine bacteria as a potential resource for the discovery of quorum sensing inhibitors.  

PubMed

Inhibitors of bacterial quorum sensing have been proposed as potentially novel therapeutics for the treatment of certain bacterial diseases. We recently reported a marine Halobacillus salinus isolate that secretes secondary metabolites capable of quenching quorum sensing phenotypes in several Gram-negative reporter strains. To investigate how widespread the production of such compounds may be in the marine bacterial environment, 332 Gram-positive isolates from diverse habitats were tested for their ability to interfere with Vibrio harveyi bioluminescence, a cell signaling-regulated phenotype. Rapid assay methods were employed where environmental isolates were propagated alongside the reporter strain. "Actives" were defined as bacteria that interfered with bioluminescence without visible cell-killing effects (antibiotic activity). A total of 49 bacterial isolates interfered with bioluminescence production in the assays. Metabolite extracts were generated from cultures of the active isolates, and 28 reproduced the bioluminescence inhibition against V. harveyi. Of those 28, five extracts additionally inhibited violacein production by Chromobacterium violaceum. Chemical investigations revealed that phenethylamides and a cyclic dipeptide are two types of secondary metabolites responsible for the observed activities. The active bacterial isolates belonged primarily to either the genus Bacillus or Halobacillus. The results suggest that Gram-positive marine bacteria are worthy of further investigation for the discovery of quorum sensing antagonists. PMID:21152942

Teasdale, Margaret E; Donovan, Kellye A; Forschner-Dancause, Stephanie R; Rowley, David C

2010-12-09

292

Studies on medium optimization for the production of antifungal and antibacterial antibiotics from a bioactive soil actinomycete  

Microsoft Academic Search

A microbial isolate, characterized as Streptomyces sp. (MTCC 6819), produced antifungal metabolite intracellularly and antibacterial metabolite extracellularly under submerged\\u000a fermentation conditions. This Gram-positive bacterium showed broad antimicrobial activity spectra against both Gram-positive\\u000a and Gram-negative bacteria. The minimum inhibitory concentration (MIC) of partially purified (68.4%) antibacterial metabolite\\u000a ranged between 50 and 12.5 ?g\\/mL against multiple-drug-resistant bacteria. The producer organism exhibited strong

Jaspreet Banga; Vandana Praveen; Vineeta Singh; C. K. M. Tripathi; Vinod Bihari

2008-01-01

293

Bis-phosphonium salts of pyridoxine: The relationship between structure and antibacterial activity.  

PubMed

A series of 23 novel bis-phosphonium salts based on pyridoxine were synthesized and their antibacterial activities were evaluated in vitro. All compounds were inactive against gram-negative bacteria and exhibited the structure-dependent activity against gram-positive bacteria. The antibacterial activity enhanced with the increase in chain length at acetal carbon atom in the order n-Pr>Et>Me. Further increasing of length and branching of alkyl chain leads to the reduction of antibacterial activity. Replacement of the phenyl substituents at the phosphorus atoms in 5,6-bis(triphenylphosphonio(methyl))-2,2,8-trimethyl-4H-[1,3]-dioxino[4,5-c]pyridine dichloride (compound 1) with n-butyl, m-tolyl or p-tolyl as well as chloride anions in the compound 1 with bromides (compound 14a) increased the activity against Staphylococcus aureus and Staphylococcus epidermidis up to 5times (MICs=1-1.25?g/ml). But in practically all cases chemical modifications of compound 1 led to the increase of its toxicity for HEK-293 cells. The only exception is compound 5,6-bis[tributylphosphonio(methyl)]-2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine dichloride (10a) which demonstrated lower MIC values against S. aureus and S. epidermidis (1?g/ml) and lower cytotoxicity on HEK-293 cells (CC50=200?g/ml). Compound 10a had no significant mutagenic and genotoxic effects and was selected for further evaluation. It should be noted that all bis-phosphonium salt based on pyridoxine were much more toxic than vancomycin. PMID:24139168

Pugachev, Mikhail V; Shtyrlin, Nikita V; Sapozhnikov, Sergey V; Sysoeva, Lubov P; Iksanova, Alfiya G; Nikitina, Elena V; Musin, Rashid Z; Lodochnikova, Olga A; Berdnikov, Eugeny A; Shtyrlin, Yurii G

2013-10-01

294

Anthemis wiedemanniana essential oil prevents LPS-induced production of NO in RAW 264.7 macrophages and exerts antiproliferative and antibacterial activities in vitro.  

PubMed

Anthemis wiedemanniana is known in folk medicine for the treatment of microbial infections, cancer and also urinary and pulmonary problems. In this study, the chemical composition of the essential oil from A. wiedemanniana was evaluated and its antibacterial activity was tested against 10 bacterial strains. The oil was also tested for its potentiality to inhibit nitric oxide production in RAW 264.7 macrophages and for its cytotoxicity against four human cancer cell lines. A. wiedemanniana oil, rich of oxygenated monoterpenes (25.4%), showed a good antibacterial activity against Gram-positive bacteria and a good activity against the two Gram-negative bacteria, Escherichia coli and Proteus vulgaris. Besides that, it exhibited a high inhibitory effect on the LPS-induced nitrite production and a strong cytotoxic activity, especially against amelanotic melanoma (C32) and large lung cell carcinoma (COR-L23) cell lines. PMID:22124231

Conforti, Filomena; Menichini, Federica; Formisano, Carmen; Rigano, Daniela; Senatore, Felice; Bruno, Maurizio; Rosselli, Sergio; Celik, Sezgin

2011-11-29

295

Synergist effect of sucrose fatty acid esters on nisin inhibition of gram-positive bacteria.  

PubMed

Nisin in combination with the sucrose fatty acid esters, sucrose palmitate (P-1570 and P-1670) or sucrose stearate (S-1570 and S-1670) was tested against a range of Gram-negative and Gram-positive bacteria. Initial liquid culture investigation showed that the sugar ester P-1670 resulted in a synergist enhancement of the bacteriostatic activity of nisin against Gram-positive bacteria and not Gram-negative bacteria. Some enhancement of the bactericidal activity of nisin against Listeria monocytogenes was also observed. This increased nisin inhibitory effect was confirmed on solid media using plates with gradients of pH and NaCl. Synergism was observed with all four sucrose fatty acid esters, which enhanced the antimicrobial activity of nisin against several strains of L. monocytogenes, Bacillus cereus (both cells and spores), Lactobacillus plantarum and Staphylococcus aureus. The combination of nisin and the sucrose fatty acid esters showed no inhibition of Gram-negative bacteria (Salmonella enteritidis, Salm. typhimurium and Pseudomonas aeruginosa). PMID:9871322

Thomas, L V; Davies, E A; Delves-Broughton, J; Wimpenny, J W

1998-12-01

296

A novel study of antibacterial activity of copper iodide nanoparticle mediated by DNA and membrane damage.  

PubMed

In this article potential activity of nanoparticles (NPs) of copper iodide (CuI) as an antibacterial agent has been presented. The nano particles are synthesized by co-precipitation method with an average size of 8 nm as determined by Transmission Electron Microscope (TEM). The average charge of the NPs is -21.5 mV at pH 7 as obtained by zeta potential measurement and purity is determined by XRD. These NPs are able to kill both gram positive and gram negative bacteria. Among the bacteria tested, DH5? is more sensitive but Bacillus subtilis is more resistant to NPs of CuI. Consequently, the MIC and MBC values of DH5? is least (0.066 mg/ml and 0.083 mg/ml respectively) and B. subtilis is highest (0.15 mg/ml and 0.18 mg/ml respectively) among the tested bacterial strains. From our studies it is inferred that CuI NPs produce reactive oxygen species (ROS) in both gram negative and gram positive bacteria and it also causes ROS mediated DNA damage for the suppression of transcription as revealed by reporter gene assay. Probably ROS is formed on the surface of NPs of CuI in presence of amine functional groups of various biological molecules. Furthermore they induce membrane damage as determined by atomic force microscopy (AFM). Thus production of ROS and membrane damage are major mechanisms of the bactericidal activity of these NPs of CuI. PMID:22521682

Pramanik, Arindam; Laha, Dipranjan; Bhattacharya, Debalina; Pramanik, Panchanan; Karmakar, Parimal

2012-04-05

297

Murine model of cutaneous infection with gram-positive cocci.  

PubMed Central

Staphylococcus aureus has remained an important cause of nosocomial wound infections, but standardized or reproducible systems for analyzing cutaneous infections caused by S. aureus do not exist. A variety of foreign materials, variable inocula, and skin traumas have been used to promote infection. To minimize these variables and ensure reproducibility, we chose a model using subcutaneous injections of a fixed quantity of dextran microbeads (Cytodex) as the foreign material added to standardized broth suspensions of S. aureus. Suspensions (0.2 ml) injected into an outbred strain of immunocompetent hairless mice generated reproducible, measurable lesions. With S. aureus Smith Diffuse, fluctuant, erythematous lesions with a peak diameter of 15 mm were observed; these lesions yielded purulent material containing gram-positive cocci and neutrophils and yielded growth of S. aureus on culture. Lesion size was proportional to the bacterial inoculum size. Histologic examination of excised lesions revealed typical abscesses. A second strain of S. aureus (SLC3) produced dermonecrosis instead of abscesses at an inoculum size of 10(7) CFU. Control injections with a sterile Cytodex suspension regularly produced nondraining, nonerythematous nodules with maximum diameters of less than or equal to 5 mm. Streptococcus pyogenes produced late-onset necrotic lesions and abscesses. Using a foreign substance, this model generates easily observed and reproducible cutaneous infection with S. aureus and streptococci that can potentially discriminate between inter- and intrastrain differences. Such a model could be used to test the pathogenicity of isogeneic strains of these bacterial species and to evaluate the efficacy of antimicrobial agents. Images

Bunce, C; Wheeler, L; Reed, G; Musser, J; Barg, N

1992-01-01

298

Solubilization of dipropofol, an antibacterial agent, using saccharide and ascorbic acid.  

PubMed

Dipropofol has a strong antibacterial activity against Gram-positive bacteria. However, it lacked the solubility in water and this property was supposed to limit its efficacy. We tried to improve the solubility and found a new solubilization method of dipropofol in water by the addition of a monosaccharide or ascorbic acid. PMID:17666822

Ogata, Masahiro; Oka, Kentaro; Seki, Masako; Hoshi, Midori; Takatsu, Hirokatsu; Mashino, Tadahiko; Urano, Shiro; Endo, Toyoshige

2007-08-01

299

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

PubMed

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. PMID:22203875

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

2011-11-17

300

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

301

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

2012-09-08

302

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

2013-10-21

303

Antibacterial peptides in hemocytes and hematopoietic tissue from freshwater crayfish Pacifastacus leniusculus: Characterization and expression pattern  

Microsoft Academic Search

A 14 amino acid residues proline\\/arginine-rich antibacterial peptide designated as astacidin 2 was purified and characterized from hemocytes of the freshwater crayfish, Pacifastacus leniusculus. Astacidin 2 has a broad range of antibacterial activity against both Gram-positive and Gram-negative bacteria. The primary sequence of astacidin 2 is RPRPNYRPRPIYRP with an amidated C-terminal and the molecular mass is 1838Da determined by mass

Pikul Jiravanichpaisal; So Young Lee; Young-A Kim; Tove Andrén; Irene Söderhäll

2007-01-01

304

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

305

Lipoteichoic Acid Is Important in Innate Immune Responses to Gram-Positive Bacteria  

Microsoft Academic Search

To define the role of lipoteichoic acid (LTA) in innate immunity to gram-positive bacteria, we investigated the production of tumor necrosis factor alpha (TNF-) by macrophages stimulated with gram-positive bac- terial culture supernatants (GPCSs) after their LTA was removed or inactivated. GPCSs were obtained from three gram-positive species (pneumococci, staphylococci, and group B streptococci) during the exponential growth phase (designated

Ho Seong Seo; Suzanne M. Michalek; Moon H. Nahm

2008-01-01

306

In vitro antifungal and antibacterial activities of pentacycloundecane tetra-amines.  

PubMed

The antifungal and antimicrobial activities of three pentacycloundecane (PCU) tetra-amine derivatives are reported herein. The in vitro activity of these PCU derivatives against yeasts (Candida albicans and non-albicans species) and filamentous fungi was evaluated using the Clinical and Laboratory Standards Institute (CLSI) M27-A2 and M38-A2 guidelines and the 2H-tetrazolium salt, (MTS) colorimetric method. The minimum inhibitory concentration against most of the tested clinical fungal strains for GKM8 and GKM9 derivatives ranges from 15.6 to 62.5 ?g/mL while GKM11 ranged from 3.9 to 7.8 ?g/mL. The GKM11 derivative was also active against fluconazole-resistant strains of fungi. The GKM11 derivative also exhibited promising activity against filamentous fungi in that it was 2.5 times more active than amphotericin B against Sporothrix schenckii. Antibacterial activity was determined using the broth microdilution method (BMM) and the iodonitrotetrazolium chloride (INT) colorimetric method. The GKM11 derivative was mainly active against Gram-positive bacteria with MIC ranging from 3.9 to 7.8 ?g/mL. Activity against Gram-negative bacteria tested was limited to Escherichia coli and Elizabethkingia meningoseptica (MIC of 31 ?g/mL). PMID:21241455

Onajole, Oluseye K; Coovadia, Yacoob; Govender, Thavendran; Kruger, Hendrik G; Maguire, Glenn E M; Naidu, Dianithi; Singh, Nisha; Govender, Patrick

2011-02-22

307

In vitro screening of Circium arvense for potential antibacterial and antifungal activities.  

PubMed

The antimicrobial activities of Circium arvense extracts were evaluated against two human gram positive (Staphylococcus aureus, Micrococcus luteus) and four gram negative pathogen (Escherichia coli, pseudomonas aeruginosa, Enterobacter, Klebsiella pneumoniae). The Methanol extracts of Circium arvense were used to obtain various fractions (X1) n-hexane, (X2) chloroform, (X3) ethyl acetate and (X4) n-butanol. The agar well diffusion assay and agar dilution susceptibility testing were carried out to determine the zone of inhibitions and the minimum inhibitory concentration respectively. Antifungal activity was employed by agar well diffusion method. The Ampicilline, Ofloxacine and Itraconazole were used as standard agents. Almost all fractions exhibited more or less antimicrobial activity. The X2 (Chloroform) fraction was reported as highly active fraction with good antimicrobial activity MIC 0.312 mg/ml against staphylococcus areous. The MBC values of fraction X2 (chloroform) was 2 times the MIC. Similarly all fractions exhibited good inhibitory activities against Aspergillus niger. The fraction X1(n-hexane) was found highly active 6(±0.11), followed by X2 (chloroform) fraction 5 (±0.17). Present study provides a base to explore the antimicrobial potential of Circium arvense. It is concluded that the Circium arvense having potential antibacterial and antifungal activities, irrespective of fact that the MIC values reported were high. Further investigations are recommended to exploit the hidden medicinal value of plant. PMID:21959814

Khan, Arifullah; Amin, Adnan; Khan, Muhammad Ayaz; Ali, Irshad

2011-10-01

308

Metabolic basis for the differential susceptibility of Gram-positive pathogens to fatty acid synthesis inhibitors  

PubMed Central

The rationale for the pursuit of bacterial type 2 fatty acid synthesis (FASII) as a target for antibacterial drug discovery in Gram-positive organisms is being debated vigorously based on their ability to incorporate extracellular fatty acids. The regulation of FASII by extracellular fatty acids was examined in Staphylococcus aureus and Streptococcus pneumoniae, representing two important groups of pathogens. Both bacteria use the same enzymatic tool kit for the conversion of extracellular fatty acids to acyl-acyl carrier protein, elongation, and incorporation into phospholipids. Exogenous fatty acids completely replace the endogenous fatty acids in S. pneumoniae but support only 50% of phospholipid synthesis in S. aureus. Fatty acids overcame FASII inhibition in S. pneumoniae but not in S. aureus. Extracellular fatty acids strongly suppress malonyl-CoA levels in S. pneumoniae but not in S. aureus, showing a feedback regulatory system in S. pneumoniae that is absent in S. aureus. Fatty acids overcame either a biochemical or a genetic block at acetyl-CoA carboxylase (ACC) in S. aureus, confirming that regulation at the ACC step is the key difference between these two species. Bacteria that possess a stringent biochemical feedback inhibition of ACC and malonyl-CoA formation triggered by environmental fatty acids are able to circumvent FASII inhibition. However, if exogenous fatty acids do not suppress malonyl-CoA formation, FASII inhibitors remain effective in the presence of fatty acid supplements.

Parsons, Joshua B.; Frank, Matthew W.; Subramanian, Chitra; Saenkham, Panatda; Rock, Charles O.

2011-01-01

309

Characterization of the antibacterial activity and the chemical components of the volatile oil of the leaves of Rubus parvifolius L.  

PubMed

Rubus parvifolius L. (Rp) is a medicinal herb that possesses antibacterial activity. In this study, we extracted the volatile oil from the leaves of Rp to assess its antibacterial activity and analyze its chemical composition. A uniform distribution design was used to optimize the extraction procedure, which yielded 0.36% (w/w) of light yellowish oil from the water extract of Rp leaves. We found that the extracted oil effectively inhibited the growth of a wide range of Gram positive and negative bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumanii, Bacillus cloacae, and Klebsiella pneumoniae. We further analyzed the components contained in the hydro-distillated Rp volatile oil by gas chromatography-mass spectroscopy. Twenty nine compounds were identified, including 4-hydroxy-3-methoxystyrene (66%), 3,7,11,15-tetramethyl-2-hexadecen-1-ol (10%) and 4-tert-butylbenzoic acid (2%). Our results suggest that one or multiple constituents contained in Rp volatile oil may account for its antibacterial activity. PMID:22732887

Cai, Yongqing; Hu, Xiaogang; Huang, Mingchun; Sun, Fengjun; Yang, Bo; He, Juying; Wang, Xianfeng; Xia, Peiyuan; Chen, Jianhong

2012-06-25

310

Ethnobotany and antibacterial activity of some plants used in traditional medicine of Zapotitlán de las Salinas, Puebla (México).  

PubMed

The village of Zapotitlán de las Salinas is situated in the Valley of Tehuacán-Cuicatlán, Puebla, Mexico. Plant species used by the local inhabitants to treat gastrointestinal diseases were identified using ethnobotanical, ethnographic and taxonomic methods. Out of 119 interviews, 44 plant species were registered, of which the following are the most frequently used (listed in descending order): Lippia graveolens H.B. et K. (Verbenaceae), Lantana achyranthifolia Desf. (Verbenaceae), Turnera diffusa (Willd.) ex Schult. (Turneraceae), Lippia oaxacana Rob. et Greenm. (Verbenaceae), Gymnolaena oaxacana (Greenm.) Rydb. (Asteraceae), Cordia curassavica (Jacq.) Roem. et Schult. (Boraginaceae), Lantana camara L. (Verbenaceae) and Acalypha hederacea Torrey (Euphorbiaceae). From these plants, hexane, chloroform and ethanol extracts were prepared in order to assess their antibacterial activity against 14 bacterial strains causing the most common gastrointestinal diseases in Mexican population. All hexane extracts showed antibacterial activity against Gram-positive and Gram-negative bacteria. There is a correlation between the frequency of mention (of plant use) and the antibacterial activity. In conclusion, the knowledge of plants most frequently used for gastrointestinal infections in Zapotitlán de las Salinas is supported by scientific rationale. PMID:12963140

Hernández, T; Canales, M; Avila, J G; Duran, A; Caballero, J; Romo de Vivar, A; Lira, R

2003-10-01

311

Codon-optimized fluorescent proteins designed for expression in low-GC gram-positive bacteria.  

PubMed

Fluorescent proteins have wide applications in biology. However, not all of these proteins are properly expressed in bacteria, especially if the codon usage and genomic GC content of the host organism are not ideal for high expression. In this study, we analyzed the DNA sequences of multiple fluorescent protein genes with respect to codons and GC content and compared them to a low-GC gram-positive bacterium, Bacillus anthracis. We found high discrepancies for cyan fluorescent protein (CFP), yellow fluorescent protein (YFP), and the photoactivatable green fluorescent protein (PAGFP), but not GFP, with regard to GC content and codon usage. Concomitantly, when the proteins were expressed in B. anthracis, CFP- and YFP-derived fluorescence was undetectable microscopically, a phenomenon caused not by lack of gene transcription or degradation of the proteins but by lack of protein expression. To improve expression in bacteria with low genomic GC contents, we synthesized a codon-optimized gfp and constructed optimized photoactivatable pagfp, cfp, and yfp, which were in contrast to nonoptimized genes highly expressed in B. anthracis and in another low-GC gram-positive bacterium, Staphylococcus aureus. Using optimized GFP as a reporter, we were able to monitor the activity of the protective antigen promoter of B. anthracis and confirm its dependence on bicarbonate and regulators present on virulence plasmid pXO1. PMID:19181829

Sastalla, Inka; Chim, Kannie; Cheung, Gordon Y C; Pomerantsev, Andrei P; Leppla, Stephen H

2009-01-30

312

A CYTOCHEMICAL LOCALIZATION OF REDUCTIVE SITES IN A GRAM-POSITIVE BACTERIUM  

PubMed Central

In bacteria the exact location of a respiratory enzyme system comparable to that of the mitochondria of other cells has remained uncertain. On the one hand, the existence of particulate "bacterial mitochondria" has been advocated (Mudd); on the other hand, important enzymes of the respiratory chain were recovered in the cytoplasmic membranes associated with some granular material (Weibull). In order to gain insight into this question, sites of reducing activity were localized in thin sections of bacteria using the reduction of potassium tellurite as an indicator. When this salt was added to the culture medium of Bacillus subtilis, it turned out that in this Gram-positive organism the reduced product is strictly bound at two sites, and that the plasma membrane does not materially gain in electron opacity through deposition of the reduced product. The reduction product is found on or in the membranes of particular organelles, which may possibly be regarded as the mitochondrial equivalents in Gram-positive bacteria, and which are sometimes seen connected to the plasma membrane. The second location is in thin rod-like elements at the cell periphery, possibly the sites from which the flagella emerge.

van Iterson, Woutera; Leene, W.

1964-01-01

313

Organic solvent adaptation of Gram positive bacteria: applications and biotechnological potentials.  

PubMed

Organic-solvent-tolerant bacteria are considered extremophiles with different tolerance levels that change among species and strains, but also depend on the inherent toxicity of the solvent. Extensive studies to understand the mechanisms of organic solvent tolerance have been done in Gram-negative bacteria. On the contrary, the information on the solvent tolerance mechanisms in Gram-positive bacteria remains scarce. Possible shared mechanisms among Gram-(-) and Gram-(+) microorganisms include: energy-dependent active efflux pumps that export toxic organic solvents to the external medium; cis-to-trans isomerization of unsaturated membrane fatty acids and modifications in the membrane phospholipid headgroups; formation of vesicles loaded with toxic compounds; and changes in the biosynthesis rate of phospholipids to accelerate repair processes. However, additional physiological responses of Gram-(+) bacteria to organic solvents seem to be specific. The aim of the present work is to review the state of the art of responsible mechanisms for organic solvent tolerance in Gram-positive bacteria, and their industrial and environmental biotechnology potential. PMID:21504787

Torres, Sebastian; Pandey, Ashok; Castro, Guillermo R

2011-04-12

314

Assessment of the in vitro Efficacy of the Novel Antimicrobial Peptide CECT7121 against Human Gram-Positive Bacteria from Serious Infections Refractory to Treatment  

Microsoft Academic Search

Background: Resistant Gram-positive bacteria are causing increasing concern in clinical practice. This work investigated theefficacy of AP-CECT7121 (an antimicrobial peptide isolated from an environmental strain of Enterococcus faecalis CECT7121) against various pathogenic Gram-positive bacteria. Methods: Strains were isolated from intensive care unit patients unresponsive to standard antibiotic treatments. Inhibitory activity of AP-CECT7121 was assessed using the agar-well diffusion method. The

M. D. Sparo; D. G. Jones; S. F. Sánchez Bruni

2009-01-01

315

Antibacterial activity against Porphyromonas gingivalis and biological characteristics of antibacterial stainless steel.  

PubMed

To evaluate the possibility of an alternative to the traditional orthodontic stainless steel implants, the antibacterial activity against Porphyromonas gingivalis (P. gingivalis) and the related cytotoxicity of a type 304 Cu bearing antibacterial stainless steel were studied. The results indicated that the antibacterial stainless steel showed excellent antibacterial property against P. gingivalis, compared with the control steel (a purchased medical grade 304 stainless steel). Compared to the control steel, there were fewer bacteria on the surface of the antibacterial stainless steel, with significant difference in morphology. The cytotoxicities of the antibacterial stainless steel to both MG-63 and KB cells were all grade 1, the same as those of the control steel. There were no significant differences in the apoptosis rates on MG-63 and KB cells between the antibacterial stainless steel and the control steel. This study demonstrates that the antibacterial stainless steel is possible to reduce the incidence of implant-related infections and can be a more suitable material for the micro-implant than the conventional stainless steel in orthodontic treatment. PMID:23352947

Zhang, Dan; Ren, Ling; Zhang, Yang; Xue, Nan; Yang, Ke; Zhong, Ming

2013-01-04

316

Antibacterial and molecular docking studies of entagenic acid, a bioactive principle from seed kernel of Entada pursaetha DC  

Microsoft Academic Search

In vitro antibacterial activity of a phytoconstituent, entagenic acid isolated from the seed kernel of Entada pursaetha DC was screened against both gram negative and gram positive bacteria. The entagenic acid showed the high antibacterial activity\\u000a against B. cereus and B. subtilis with minimal inhibitory concentration of 200 ?g ml?1 and possesses better glucosamine-6-phosphate synthase inhibition in molecular docking studies with minimum

Shimoga Muddappa Vidya; Venkatarangaiah Krishna; Bukkambudi Krishnaswamy Manjunatha; Kashi Prakash-Gupta Rajesh; Basavapattana Rudresh Bharath; Hanumanthappa Manjunatha

317

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

318

Antibacterial activity of doxycycline-loaded nanoparticles.  

PubMed

Doxycycline is a tetracycline antibiotic with a potent antibacterial activity against a wide variety of bacteria. However, poor cellular penetration limits its use for the treatment of infectious disease caused by intracellular pathogens. One potential strategy to overcome this problem is the use of nanotechnology that can help to easily target the intracellular sites of infection. The antibacterial activity of these antibiotics is enhanced by encapsulating it in polymeric nanoparticles. In this study, we describe the improvement of the entrapment efficiency of doxycycline hydrochloride (doxycycline)-loaded PLGA:PCL nanoparticles up to 70% with variation of different formulation parameters such as polymer ratio, amount of drug loading (w/w), solvent selection, electrolyte addition, and pH alteration in the formulation. We have evaluated the efficacy of these nanoparticles over native doxycycline against a strain of Escherichia coli (DH5?) through growth inhibition and colony counting. The results indicate that doxycycline-loaded nanoparticles have superior effectiveness compared to native doxycycline against the above bacterial strain, resulting from the sustained release of doxycycline from nanoparticles. These results are encouraging for the use of these doxycycline-loaded nanoparticles for the treatment of infections caused by doxycycline-sensitive bacteria. PMID:22568901

Misra, Ranjita; Sahoo, Sanjeeb K

2012-01-01

319

Antibacterial activity of clarithromycin loaded PLGA nanoparticles.  

PubMed

Novel drug delivery systems such as nanoparticles (NPs) have been proved to enhance the effectiveness of many drugs. Clarithromycin is a broad spectrum macrolide antibiotic, used in many infectious conditions like upper and lower respiratory tract infections, and skin and other soft tissue infections. This paper describes the preparation and enhanced in vitro antibacterial activities of clarithromycin loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles. A modified quasi-emulsion solvent diffusion (MQESD) method was used to prepare clarithromycin (CLR) NPs. The antibacterial activity of the NPs was evaluated using the agar well diffusion method against Escherichia coli (PTCC 1330), Haemophilus influenzae (PTCC 1623), Salmonella typhi (PTCC 1609), Staphylococcus aureus (PTCC 1112) and Streptococcus pneumoniae (PTCC 1240). The inhibition zone diameters related to each nano formulation were compared with those for untreated CLR at the same concentrations. The results indicated that the mean inhibition zone diameters of NPs against all the bacteria tested were significantly higher than those of untreated CLR, particularly in the case of S. aureus. The increased potency of CLR NPs may be related to some physicochemical properties of NPs like modified surface characteristics, lower drug degradation, and increased drug adsorption and uptake. PMID:22393833

Valizadeh, H; Mohammadi, G; Ehyaei, R; Milani, M; Azhdarzadeh, M; Zakeri-Milani, P; Lotfipour, F

2012-01-01

320

Chemical composition, olfactory analysis and antibacterial activity of Thymus vulgaris chemotypes geraniol, 4-thujanol/terpinen-4-ol, thymol and linalool cultivated in southern France.  

PubMed

The essential oils of four chemotypes of Thymus vulgaris L. (Lamiaceae) were analyzed for their composition and antibacterial activity to assess their different properties. GC-MS and GC-FID analyses revealed that the essentials oils can be classified into the chemotypes thymol (41.0% thymol), geraniol (26.4% geraniol), linalool (72.5% linalool) and 4-thujanol/terpinen-4-ol (42.2% cis- and 7.3% trans-sabinene hydrate, 6.5 % terpinen-4-ol). The olfactory examination confirmed the explicit differences between these chemotypes. Furthermore, antibacterial activity was investigated against several strains of two Gram-positive (Brochothrix thermosphacta and Staphylococcus aureus) and four Gram-negative food-borne bacteria (Escherichia coli, Salmonella abony, Pseudomonas aeruginosa and P. fragi). All essential oil samples were demonstrated to be highly effective against Gram-positive strains, whereas the impact on Gram-negative microorganisms was significantly smaller, but still considerable. The results obtained indicate that, despite their different properties, the essential oils of selected T. vulgaris chemotypes are potent antimicrobials to be employed as useful additives in food products as well as for therapeutic applications. PMID:22978238

Schmidt, Erich; Wanner, Jürgen; Hiiferl, Martina; Jirovetz, Leopold; Buchbauer, Gerhard; Gochev, Velizar; Girova, Tania; Stoyanova, Albena; Geissler, Margit

2012-08-01

321

Native-valve endocarditis caused by Mycobacterium chelonae, misidentified as polymicrobial gram-positive bacillus infection.  

PubMed

Mycobacterium chelonae, a species of rapidly growing mycobacteria, may grow in routine blood culture media and stain as gram-positive bacilli, which may cause diagnostic confusion. A patient with native-valve endocarditis caused by M. chelonae, which was misidentified as various gram-positive bacilli, is presented. PMID:23053507

Takekoshi, Daisuke; Al-Heeti, Omar; Belvitch, Patrick; Schraufnagel, Dean E

2012-10-10

322

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

323

Antibacterial Activity of Eravacycline (TP-434), a Novel Fluorocycline, against Hospital and Community Pathogens.  

PubMed

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. PMID:23979750

Sutcliffe, J A; O'Brien, W; Fyfe, C; Grossman, T H

2013-08-26

324

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

2013-04-02

325

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

326

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

327

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

2013-04-11

328

Three novel Anas platyrhynchos avian ?-defensins, upregulated by duck hepatitis virus, with antibacterial and antiviral activities.  

PubMed

Three novel Anas platyrhynchos avian ?-defensins (Apl_AvBDs), Apl_AvBD4, 7 and 12, were identified successfully and characterized in tissues from Peking ducks in the present study. The cDNA fragment of Apl_AvBD4 contained 171 bp, and encoded 56 amino acids. The complete nucleotide sequences of Apl_AvBD7 and 12 contained 204 bp and 198 bp open reading frames, which encoded 67 and 65 amino acids, respectively. Both recombinant and synthetic forms of the three Apl_AvBDs showed antibacterial activity against most of the bacteria investigated, including Gram-negative and Gram-positive bacteria, except for Salmonella choleraesuis. In addition, the antibacterial activity of all the three Apl_AvBDs decreased significantly in 150 mM NaCl. Significant antiviral activity of the three Apl_AvBDs was shown against duck hepatitis virus (DHV). However, none of the Apl_AvBDs showed significant hemolytic activity. Additionally, the expressions of the three Apl_AvBDs in response to DHV infection was highly variable, and significant upregulation of Apl_AvBD7 in liver was found in response to infection at different time points. Expression of Apl_AvBD4 in thymus, and of Apl_AvBD7 in bone marrow was induced in a time-dependent fashion by DHV infection. In contrast, expression of Apl_AvBD12 was found to be significantly decreased, and was hard to detect in cecal tonsil, spleen, bursa of Fabricius, and thymus of ducks at some time points after DHV infection. The present results demonstrate that Apl_AvBDs play vital roles in the immune response of ducks against bacterial and viral pathogens. PMID:21856003

Ma, Deying; Lin, Lijuan; Zhang, Kexin; Han, Zongxi; Shao, Yuhao; Liu, Xiaoli; Liu, Shengwang

2011-10-01

329

Palladium(II) complexes of NS donor ligands derived from steroidal thiosemicarbazones as antibacterial agents.  

PubMed

We have investigated the antibacterial activity of some new steroidal thiosemicarbazones and their Pd(II) metal complexes were prepared by the reaction of the thiosemicarbazones with [Pd(DMSO)(2)Cl(2)]. The steroidal thiosemicarbazones were prepared by the reaction of thiosemicarbazides with a steroidal ketone. The structures of these compounds were elucidated by IR, (1)H-NMR, (13)C-NMR, FAB mass spectroscopic methods, elemental analyses and TGA analysis. The antibacterial activity of these compounds were tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria. The results showed that steroidal complexes are better inhibitors of both types of the bacteria (Gram-positive and Gram-negative) as compared to steroidal thiosemicarbazones. Compound Ia displays remarkable antibacterial activity as compared to amoxicillin. PMID:20657393

Asiri, Abdullah M; Khan, Salman A

2010-07-08

330

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

331

Naturally occurring phenolic antibacterial compounds show effectiveness against oral bacteria by a quantitative structure-activity relationship study.  

PubMed

Natural and synthetic phenolic compounds were evaluated against oral bacteria. A quantitative structure-active relationship approach was applied to the germ-kill activity for a range of phenolic compounds. The lipophilicity and steric effects were found to be two key factors in determining germ-kill activity. The optimum lipophilicity, measured by the logarithm of the octanol/water partition coefficient, or log P, was found to be 5.5 for Fusobacterium nucleatum , a Gram-negative type of oral bacteria that causes bad breath. The optimum log P was found to be 7.9 for Streptococcus mutans , a Gram-positive type of oral bacteria that causes tooth decay. The steric effect of substituents ortho to the phenolic group was found to be critical in reducing antibacterial activity despite having increased lipid solubility approaching the optimum lipophilicity value. The antibacterial activity of phenolic compounds is likely exerted by multiple functions, primarily comes from its ability to act as a nonionic surface-active agent therefore disrupting the lipid-protein interface. PMID:19007234

Greenberg, Michael; Dodds, Michael; Tian, Minmin

2008-12-10

332

Secretory Phospholipase A2 Is the Principal Bactericide for Staphylococci and Other Gram-Positive Bacteria in Human Tears  

Microsoft Academic Search

We examined human tears for molecules that killed gram-positive bacteria. The principal mediator of bactericidal activity against staphylococci proved to be a calcium-dependent enzyme, secretory phospholipase A2. Whereas the concentration of secretory phospholipase A2 in the normal tear film exceeded 30 mg\\/ml, only 1.1 ng (<0.1 nM) of the enzyme per ml sufficed to kill Listeria monocytogenes and 15 to

XIAO-DAN QU; ROBERT I. LEHRER

1998-01-01

333

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

334

Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity  

NASA Astrophysics Data System (ADS)

New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL1 and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL2 derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML(1-2)2 have been synthesized, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate ? coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mn < Zn < Cu < Co < Ni. The ligands and their complexes were tested for in vitro antibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu > Mn > Ni > Co > Zn.

Devi, Jai; Batra, Nisha; Malhotra, Rajesh

2012-11-01

335

Antibacterial activity of Citrus reticulata peel extracts.  

PubMed

Citrus peels were successively extracted with hexane, chloroform and acetone using a soxhlet extractor. The hexane and chloroform extracts were fractionated into alcohol-soluble and alcohol-insoluble fractions. These fractions were tested against different gram positive and gram negative bacteria. The EtOH-soluble fraction was found to be most effective. Fractionation of EtOH-soluble fraction on silica gel column yielded three polymethoxylated flavones, namely desmethylnobiletin, nobiletin and tangeretin. Their structures were confirmed by UV, 1H, 13C NMR and mass spectral studies. The findings indicated a potential of these natural compounds as biopreservatives in food applications. PMID:11204182

Jayaprakasha, G K; Negi, P S; Sikder, S; Rao, L J; Sakariah, K K

336

Lipids Including Cholesteryl Linoleate and Cholesteryl Arachidonate Contribute to the Inherent Antibacterial Activity of Human Nasal Fluid1  

PubMed Central

Mucosal surfaces provide first-line defense against microbial invasion through their complex secretions. The antimicrobial activities of proteins in these secretions have been well delineated, but the contributions of lipids to mucosal defense have not been defined. We found that normal human nasal fluid contains all major lipid classes (?g/ml), as well as lipoproteins and apolipoprotein AI. The predominant less polar lipids were myristic, palmitic, palmitoleic, stearic, oleic, and linoleic acid, cholesterol, and cholesteryl palmitate, -linoleate, and -arachidonate. Normal human bronchioepithelial cell secretions exhibited a similar lipid composition. Removal of less-polar lipids significantly decreased the inherent antibacterial activity of nasal fluid against Pseudomonas aeruginosa, which was in part restored after replenishing the lipids. Furthermore, lipids extracted from nasal fluid exerted direct antibacterial activity in synergism with the antimicrobial peptide HNP-2 and liposomal formulations of cholesteryl linoleate and cholesteryl arachidonate were active against P. aeruginosa at physiological concentrations as found in nasal fluid and exerted inhibitory activity against other gram negative and gram positive bacteria. These data suggest that host-derived lipids contribute to mucosal defense. The emerging concept of host-derived antimicrobial lipids unveils novel roads to a better understanding of the immunology of infectious diseases.

Do, Thai Q.; Moshkani, Safiehkhatoon; Castillo, Patricia; Anunta, Suda; Pogosyan, Adelina; Cheung, Annie; Marbois, Beth; Faull, Kym F.; Ernst, William; Chiang, Su Ming; Fujii, Gary; Clarke, Catherine F.; Foster, Krishna; Porter, Edith

2008-01-01

337

Composition and in vitro antibacterial activity of essential oils from four Satureja species growing in Iran.  

PubMed

The composition and in vitro antibacterial activity of essential oils from four Satureja species (S. bachtiarica, S. khuzistanica, S. mutica and S. rechingeri) growing in Iran were determined. According to the results of GC-FID and GC-MS analysis, all oil samples were principally composed of phenolic constituents (carvacrol and/or thymol) with the percentages ranging from 41.2% (S. bachtiarica) to 77.7% (S. rechingeri). Determining antibacterial activities by the disc diffusion method against two Gram-positive and two Gram-negative bacteria revealed the maximum activity against Bacillus cereus with a range of minimum inhibitory concentration values from 0.25 to 1?mg?mL(-1) and minimum bactericidal concentration values from 0.5 to 1?mg?mL(-1). The oils of S. khuzistanica and S. rechingeri appeared to be more active in general than those of other species. In conclusion, the essential oils of studied Satureja species have the potential to be considered as alternatives for synthetic food preservatives. PMID:21827283

Hadian, Javad; Akramian, Morteza; Heydari, Hajar; Mumivand, Hasan; Asghari, Behvar

2011-08-09

338

Antibacterial, anti-inflammatory, anti-cholinesterase and mutagenic effects of extracts obtained from some trees used in South African traditional medicine  

Microsoft Academic Search

Extracts obtained from 10 trees used in South African traditional medicine were screened for antibacterial, anti-inflammatory (COX-1 and COX-2) and anti-cholinesterase activities and investigated for potential mutagenic effects using the Ames test. Antibacterial activity was detected using the disc-diffusion and micro-dilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli

I. M. S. Eldeen; E. E. Elgorashi; J. van Staden

2005-01-01

339

Preparation of active antibacterial LDPE surface through multistep physicochemical approach II: graft type effect on antibacterial properties.  

PubMed

Three monomers (allylamine, N-allylmethylamine and N,N-dimethylallylamine) were used for grafting onto air plasma activated LDPE surface. Antibacterial agent triclosan was anchored on such substrates. Influence of graft type on the antibacterial properties was determined. Increase of antibacterial activity and amount of deposited antibacterial agent for N-allylmethylamine and N,N-dimethylallylamine monomers were examined. Surface characteristics were measured by means of static contact angle measurement with surface energy evaluation, ATR-FTIR spectroscopy, XPS and SEM characterization analysis. Antibacterial properties were tested in vitro by inhibition zone method on agar plates for Staphylococcus aureus and Escherichia coli strains. PMID:23104040

Bílek, František; Sulovská, Kate?ina; Lehocký, Marián; Sáha, Petr; Humpolí?ek, Petr; Mozeti?, Miran; Junkar, Ita

2012-09-12

340

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

341

Analgesic, Antibacterial and Antiviral Activities of 2-(5-Alkyl-1,3,4-oxadiazol-2-yl)-3H-benzo[f]chromen-3-ones  

PubMed Central

A novel series of 2-(5-alkyl-1,3,4-oxadiazol-2-yl)-3H-benzo[f]chromen-3-ones (4a-e) have been evaluated for analgesic, antibacterial and antiviral activities. Analgesic activity was carried out using acetic acid-induced writhing method in Swiss albino male mice. The antibacterial activity was performed against Gram-positive and Gram-negative clinical strains by agar well diffusion method. The in vitro antiviral activity was carried out against camelpox and buffalopox viruses. The analgesic activity exhibited by the compounds 4a, 4c and 4d were found to be more significant compared to the standard. The bacterial activity was determined by the inhibition of growth of the organism by the drugs at different concentrations. All the compounds showed significant activity when compared with the drug ciprofloxacin. The in vitro antiviral activity of the compound 4b tested against camelpox and buffalopox viruses revealed no activity when tested at concentrations of 250 ?g. The compound 4b did not alter the titres of both the viruses and the titres remain, respectively, 106.5 TCID50 and 106.74 TCID50 per ml for camelpox vaccine virus and buffalopox vaccine virus. However, the compounds 4a-e showed significant analgesic and antibacterial activities.

Raghavendra, R.; Mahadevan, K. M.; Satyanarayan, N. D.; Bhanuprakash, V.; Venkatesan, G.; Yogisharadhya, R.

2012-01-01

342

Towards long-lasting antibacterial stainless steel surfaces by combining double glow plasma silvering with active screen plasma nitriding.  

PubMed

Antibacterial surface modification of biomedical materials has evolved as a potentially effective method for preventing bacterial proliferation on the surfaces of devices. However, thin antibacterial coatings or modified layers can be easily worn down when interacting with other surfaces in relative motion, thus leading to a low durability of the antibacterial surface. To this end, novel biomaterial surfaces with antibacterial Ag agents and a wear-resistant S-phase have been generated on stainless steel by duplex plasma silvering-nitriding techniques for application to load-bearing medical devices. The chemical composition, microstructure, surface topography, roughness and wettability of SS surfaces were characterised using glow discharge optical emission spectroscopy, energy-dispersive spectroscopy/wavelength dispersive spectrometry (WDS), X-ray diffraction, atomic force microscopy and a contact angle goniometer. Optimal surface design for high antimicrobial activity and prolonged durability has been achieved, as evidenced by rapid bacterial killing rates (within 6h), an ultra hard matrix (875 ± 25 Hv), high load-bearing capacity (critical load 37 N) and excellent wear resistance (wear rate 4.9 × 10?? mm³ m?¹). Ag embedded in the hard substrate of fcc compounds M(4)N (M=Fe, Cr, Ag, etc.) and the expanded fcc nitrogen S-phase shows deep infiltration of 6 ± 1 ?m, and provides bactericidal activity against both Gram-negative Escherichia coli NCTC 10418 and Gram-positive Staphylococcus epidermidis NCTC 11047 of over 97% and 90%, respectively, within 6h. The presence of silver in the surface before and after scratching under a progressive load applied up to 60 N using a diamond stylus was confirmed by WDS. PMID:20727993

Dong, Y; Li, X; Tian, L; Bell, T; Sammons, R L; Dong, H

2010-08-19

343

A Novel Alkaloid from Marine-Derived Actinomycete Streptomyces xinghaiensis with Broad-Spectrum Antibacterial and Cytotoxic Activities.  

PubMed

Due to the increasing emergence of drug-resistant bacteria and tumor cell lines, novel antibiotics with antibacterial and cytotoxic activities are urgently needed. Marine actinobacteria are rich sources of novel antibiotics, and here we report the discovery of a novel alkaloid, xinghaiamine A, from a marine-derived actinomycete Streptomyces xinghaiensis NRRL B24674(T). Xinghaiamine A was purified from the fermentation broth, and its structure was elucidated based on extensive spectroscopic analysis, including 1D and 2D NMR spectrum as well as mass spectrometry. Xinghaiamine A was identified to be a novel alkaloid with highly symmetric structure on the basis of sulfoxide functional group, and sulfoxide containing compound has so far never been reported in microorganisms. Biological assays revealed that xinghaiamine A exhibited broad-spectrum antibacterial activities to both Gram-negative persistent hospital pathogens (e.g. Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) and Gram-positive ones, which include Staphylococcus aureus and Bacillus subtilis. In addition, xinghaiamine A also exhibited potent cytotoxic activity to human cancer cell lines of MCF-7 and U-937 with the IC50 of 0.6 and 0.5 µM, respectively. PMID:24098415

Jiao, Wence; Zhang, Fenghua; Zhao, Xinqing; Hu, Jiehan; Suh, Joo-Won

2013-10-01

344

A Novel Alkaloid from Marine-Derived Actinomycete Streptomyces xinghaiensis with Broad-Spectrum Antibacterial and Cytotoxic Activities  

PubMed Central

Due to the increasing emergence of drug-resistant bacteria and tumor cell lines, novel antibiotics with antibacterial and cytotoxic activities are urgently needed. Marine actinobacteria are rich sources of novel antibiotics, and here we report the discovery of a novel alkaloid, xinghaiamine A, from a marine-derived actinomycete Streptomyces xinghaiensis NRRL B24674T. Xinghaiamine A was purified from the fermentation broth, and its structure was elucidated based on extensive spectroscopic analysis, including 1D and 2D NMR spectrum as well as mass spectrometry. Xinghaiamine A was identified to be a novel alkaloid with highly symmetric structure on the basis of sulfoxide functional group, and sulfoxide containing compound has so far never been reported in microorganisms. Biological assays revealed that xinghaiamine A exhibited broad-spectrum antibacterial activities to both Gram-negative persistent hospital pathogens (e.g. Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) and Gram-positive ones, which include Staphylococcus aureus and Bacillus subtilis. In addition, xinghaiamine A also exhibited potent cytotoxic activity to human cancer cell lines of MCF-7 and U-937 with the IC50 of 0.6 and 0.5 µM, respectively.

Jiao, Wence; Zhang, Fenghua; Zhao, Xinqing; Hu, Jiehan; Suh, Joo-Won

2013-01-01

345

Isolating "Unknown" Bacteria in the Introductory Microbiology Laboratory: A New Selective Medium for Gram-Positives.  

ERIC Educational Resources Information Center

|Describes the development, preparation, and use of a medium that can select against a wide variety of Gram-negative bacteria while still allowing growth and differentiation of a wide range of Gram-positives. (WRM)|

McKillip, John L.; Drake, MaryAnne

1999-01-01

346

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

347

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

348

Management of Gram-Positive Bacterial Disease: Staphylococcus aureus , Streptococcal, Pneumococcal and Enterococcal Infections  

Microsoft Academic Search

\\u000a Gram-positive bacteria are a diverse group of organisms that are a major source of morbidity and mortality in patients with\\u000a cancer. The increasing use of long-term indwelling central catheters and cytotoxic chemotherapies has contributed to the emergence\\u000a of Gram-positive bacteria as the leading cause of bacteremia in cancer patients. These organisms are also among the foremost\\u000a causes of pneumonia, skin

Samuel Shelburne; Daniel M. Musher

349

A consensus statement on empiric therapy for suspected gram-positive infections in surgical patients  

Microsoft Academic Search

Background: Multidrug resistance among gram-positive pathogens in tertiary and other care centers is common. A systematic decision pathway to help select empiric antibiotic therapy for suspected gram-positive postsurgical infections is presented. Data sources: A Medline search with regard to empiric antibiotic therapy was performed and assessed by the 15-member expert panel. Two separate panel meetings were convened and followed by

Joseph S. Solomkin; H. Stephen Bjornson; Miguel Cainzos; E. Patchen Dellinger; Lorenzo Dominioni; Robert Eidus; Eugen Faist; David Leaper; James T. Lee; Pamela A. Lipsett; Lena Napolitano; Carl L. Nelson; Robert G. Sawyer; John Weigelt; Samuel Eric Wilson

2004-01-01

350

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

351

An Export-Specific Reporter Designed for Gram-Positive Bacteria: Application to Lactococcus lactis  

Microsoft Academic Search

The identification of exported proteins by fusion studies, while well developed for gram-negative bacteria, is limited for gram-positive bacteria, in part due to drawbacks of available export reporters. In this work, we demonstrate the export specificity and use of the Staphylococcus aureus secreted nuclease (Nuc) as a reporter for gram-positive bacteria. Nuc devoid of its export signal (called DSPNuc) was

ISABELLE POQUET; S. DUSKO EHRLICH; ALEXANDRA GRUSS

1998-01-01

352

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

Microsoft Academic Search

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 a-helical cationic peptides related to bee melittin and silk

MONISHA G. SCOTT; MICHAEL R. GOLD; ROBERT E. W. HANCOCK

1999-01-01

353

Translocation of proteins across the cell envelope of Gram-positive bacteria  

Microsoft Academic Search

In contrast to Gram-negative bacteria, secretory proteins of Gram-positive bacteria only need to traverse a single membrane to enter the extracellular environment. For this reason, Gram-positive bacteria (e.g. various Bacillus species) are often used in industry for the commercial production of extracellular proteins that can be produced in yields of several grams per liter culture medium. The central components of

Karel H. M. van Wely; Jelto Swaving; Roland Freudl; Arnold J. M. Driessen

2001-01-01

354

Distribution of mef(A) in Gram-Positive Bacteria from Healthy Portuguese Children  

Microsoft Academic Search

We screened 615 gram-positive isolates from 150 healthy children for the presence of the erm(A), erm(B), erm(C), erm(F), and mef(A) genes. The mef(A) genes were found in 20 (9%) of the macrolide-resistant isolates, including Enterococcus spp., Staphylococcus spp., and Streptococcus spp. Sixteen of the 19 gram-positive isolates tested carried the other seven open reading frames (ORFs) described in Tn1207.1, a

Vicki A. Luna; Marc Heiken; Kathleen Judge; Catherine Ulep; Nicole Van Kirk; Henrique Luis; Mario Bernardo; Jose Leitao; Marilyn C. Roberts

2002-01-01

355

Protein sorting to the cell wall envelope of Gram-positive bacteria  

Microsoft Academic Search

The covalent anchoring of surface proteins to the cell wall envelope of Gram-positive bacteria occurs by a universal mechanism requiring sortases, extracellular transpeptidases that are positioned in the plasma membrane. Surface protein precursors are first initiated into the secretory pathway of Gram-positive bacteria via N-terminal signal peptides. C-terminal sorting signals of surface proteins, bearing an LPXTG motif or other recognition

Hung Ton-That; Luciano A. Marraffini; Olaf Schneewind

2004-01-01

356

Antibacterial activity of quinoxalines, quinazolines, and 1,5-naphthyridines.  

PubMed

Several phenyl substituted naphthalenes and isoquinolines have been identified as antibacterial agents that inhibit FtsZ-Zing formation. In the present study we evaluated the antibacterial of several phenyl substituted quinoxalines, quinazolines and 1,5-naphthyridines against methicillin-sensitive and methicillin-resistant Staphylococcusaureus and vancomycin-sensitive and vancomycin-resistant Enterococcusfaecalis. Some of the more active compounds against S. aureus were evaluated for their effect on FtsZ protein polymerization. Further studies were also performed to assess their relative bactericidal and bacteriostatic activities. The notable differences observed between nonquaternized and quaternized quinoxaline derivatives suggest that differing mechanisms of action are associated with their antibacterial properties. PMID:23891185

Parhi, Ajit K; Zhang, Yongzheng; Saionz, Kurt W; Pradhan, Padmanava; Kaul, Malvika; Trivedi, Kalkal; Pilch, Daniel S; LaVoie, Edmond J

2013-06-26

357

Isomerization of an Antimicrobial Peptide Broadens Antimicrobial Spectrum to Gram-Positive Bacterial Pathogens  

PubMed Central

The branched M33 antimicrobial peptide was previously shown to be very active against Gram-negative bacterial pathogens, including multidrug-resistant strains. In an attempt to produce back-up molecules, we synthesized an M33 peptide isomer consisting of D-aminoacids (M33-D). This isomeric version showed 4 to 16-fold higher activity against Gram-positive pathogens, including Staphylococcus aureus and Staphylococcus epidermidis, than the original peptide, while retaining strong activity against Gram-negative bacteria. The antimicrobial activity of both peptides was influenced by their differential sensitivity to bacterial proteases. The better activity shown by M33-D against S. aureus compared to M33-L was confirmed in biofilm eradication experiments where M33-L showed 12% activity with respect to M33-D, and in vivo models where Balb-c mice infected with S. aureus showed 100% and 0% survival when treated with M33-D and M33-L, respectively. M33-D appears to be an interesting candidate for the development of novel broad-spectrum antimicrobials active against bacterial pathogens of clinical importance.

Pollini, Simona; Luca, Vincenzo; Carnicelli, Veronica; Brunetti, Jlenia; Lelli, Barbara; Bindi, Stefano; Scali, Silvia; Di Giulio, Antonio; Rossolini, Gian Maria; Mangoni, Maria Luisa; Bracci, Luisa; Pini, Alessandro

2012-01-01

358

Antibacterial principles from Myristica fragrans seeds.  

PubMed

Nutmeg (Myristica fragrans) is used in food preparations for its aromatic flavor. The present investigation was undertaken to evaluate the antibacterial activity of constituents of M. fragrans seeds. Seeds of M. fragrans were powdered and extracted with chloroform to obtain trimyristin, which on saponification yielded myristic acid. The mother liquor remaining after separation of trimyristin was concentrated and column-chromatographed with petroleum ether to separate myristicin. Antibacterial activity of these isolated constituents was evaluated by determination of minimum inhibitory concentration against selected Gram-positive and Gram-negative organisms. All the constituents isolated from nutmeg exhibited good antibacterial activity. This study shows the potential of natural compounds in replacement of synthetic preservatives. PMID:17004905

Narasimhan, Balasubramanian; Dhake, Avinash S

2006-01-01

359

Design, synthesis and antibacterial activity of minor groove binders: the role of non-cationic tail groups.  

PubMed

The design and synthesis of a new class of minor groove binder (MGBs) in which, the cationic tail group has been replaced by a neutral, polar variant including cyanoguanidine, nitroalkene, and trifluoroacetamide groups. Antibacterial activity (against Gram positive bacteria) was found for both the nitroalkene and trifluoroacetamide groups. For the case of the nitroalkene tail group, strong binding of a minor groove binder containing this tail group was demonstrated by both DNA footprinting and melting temperature measurements, showing a correlation between DNA binding and antibacterial activity. The compounds have also been evaluated for binding to the hERG ion channel to determine whether non-cationic but polar substituents might have an advantage compared with conventional cationic tail groups in avoiding hERG binding. In this series of compounds, it was found that whilst non-cationic compounds generally had lower affinity to the hERG ion channel, all of the compounds studied bound weakly to the hERG ion channel, probably associated with the hydrophobic head groups. PMID:22948178

Khalaf, Abedawn I; Bourdin, Claire; Breen, David; Donoghue, Gavin; Scott, Fraser J; Suckling, Colin J; Macmillan, Donna; Clements, Carol; Fox, Keith; Sekibo, Doreen A T

2012-08-16

360

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

2013-06-28

361

Antibacterial activity of some Indian medicinal plants  

Microsoft Academic Search

Aqueous extracts of ten medicinal plants were examined for their antibacterial potential against some reference strains of\\u000a human pathogenic bacteria. Anethum graveolens, Elettaria cardamomum, Foeniculum vulgare, Trachyspermum ammi and Viola odorata were found to be better\\/equally effective compared to standard antibiotics. V. odorata was the most effective antibacterial with minimum inhibitory concentration values ranging from 1 to 2%. The results

Daljit Singh Arora; Gurinder Jeet Kaur

2007-01-01

362

Antibacterial activity of two plant extracts on eight burn pathogens.  

PubMed

Antibacterial activity of crude alcoholic extract of Datura alba and Celosia argentea leaves were studied against pathogens isolated from infected burn patients. The disc-diffusion method showed significant zone of lysis against all the pathogens studied and the results are comparable to the conventional antibiotic cream namely Silver Sulphadiazine (SSD). On comparing the efficiency of the two extracts, extract of D. alba exhibited more than 50% increase in antibacterial activity compared to C. argentea. PMID:12686442

Gnanamani, A; Priya, K Shanmuga; Radhakrishnan, N; Babu, Mary

2003-05-01

363

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

364

Antibacterial activity of heavy metal-loaded natural zeolite.  

PubMed

The antibacterial activity of natural zeolitized tuffs containing 2.60wt.% Cu(2+), 1.47 Zn(2+) or 0.52 Ni(2+) were tested. Antibacterial activities of the zeolites against Escherichia coli and Staphylococcus aureus were tested after 1h and 24h of exposure to 1g of the zeolite in 100mL of three different media, namely Luria Bertani, synthetic wastewater and secondary effluent wastewater. The antibacterial activities of the zeolites in Luria Bertani medium were significantly lower than those in the other media and negatively correlated with the chemical oxygen demand of the media. The Ni-loaded zeolite showed high leaching of Ni(2+) (3.44-9.13wt.% of the Ni(2+) loaded) and weak antibacterial activity in the effluent water. Since Cu-loaded zeolite did not leach Cu(2+) and the leaching of Zn(2+) from Zn-loaded zeolite was low (1.07-1.61wt.% of the Zn(2+) loaded), the strong antibacterial activity classified the Cu- and Zn-loaded zeolite as promising antibacterial materials for disinfection of secondary effluent water. PMID:22178285

Hrenovic, Jasna; Milenkovic, Jelena; Ivankovic, Tomislav; Rajic, Nevenka

2011-12-01

365

Use of lipids to potentiate the antibacterial activity of aminoglycosides.  

PubMed Central

Linolenyl alcohol has been shown to inhibit the in vitro growth of several species of gram-positive bacteria. Since the double bonds in linolenyl alcohol could undergo autooxidation, the antimicrobial activities of saturated primary alcohols of similar molecular sizes against Streptococcus mutans BHT were evaluated. Tridecan-1-ol was identified as the most active compound, eliciting a bacteriostatic effect at concentrations at which growth occurred in the presence of other saturated alcohols or linolenyl alcohol. Evidence is also presented that the combined use of tridecan-1-ol and gentamicin sulfate produces a synergistic effect that is bactericidal to S. mutans BHT. A similar bactericidal response was observed when tridecan-1-ol was combined with other aminoglycosides or tested alone against other strains of S. mutans.

Gilbertson, J R; Langkamp, H H; Connamacher, R; Platt, D

1984-01-01

366

Antibacterial efficacy of raw and processed honey.  

PubMed

In vitro antibacterial activity of methanol, ethanol, and ethyl acetate extracts of raw and processed honey was tested against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Enterococcus faecalis, and Micrococcus luteus) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi). Both types of honey showed antibacterial activity against tested organisms with the zone of inhibition (ZOI) ranging from 6.94 to 37.94?mm, while E. coli, S. typhi, and P. aeruginosa showed that sensibility towards all the extracts with ZOI ranges between 13.09 to 37.94?mm. The methanol extract showed more potent activity than other organic extracts. Gram-negative bacteria were found to be more susceptible as compared to Gram-positive bacteria except E. faecalis. The broth microdilution assay gave minimum inhibitory concentrations (MIC) value of 625??g/mL, while the minimum bactericidal concentration (MBC) ranges between 625??g/mL 2500??g/mL. The study showed that honey has antibacterial activity (bacteriostatic and bactericidal effect), similar to antibiotics, against test organisms and provides alternative therapy against certain bacteria. PMID:21350671

Mohapatra, D P; Thakur, V; Brar, S K

2010-12-29

367

Gram-positive pathogenic bacteria induce a common early response in human monocytes  

PubMed Central

Background We infected freshly isolated human peripheral monocytes with live bacteria of three clinically important gram-positive bacterial species, Staphylococcus aureus, Streptococcus pneumoniae and Listeria monocytogenes and studied the ensuing early transcriptional response using expression microarrays. Thus the observed response was unbiased by signals originating from other helper and effector cells of the host and was not limited to induction by solitary bacterial constituents. Results Activation of monocytes was demonstrated by the upregulation of chemokine rather than interleukin genes except for the prominent expression of interleukin 23, marking it as the early lead cytokine. This activation was accompanied by cytoskeleton rearrangement signals and a general anti-oxidative stress and anti-apoptotic reaction. Remarkably, the expression profiles also provide evidence that monocytes participate in the regulation of angiogenesis and endothelial function in response to these pathogens. Conclusion Regardless of the invasion properties and survival mechanisms of the pathogens used, we found that the early response comprised of a consistent and common response. The common response was hallmarked by the upregulation of interleukin 23, a rather unexpected finding regarding Listeria infection, as this cytokine has been linked primarily to the control of extracellular bacterial dissemination.

2010-01-01

368

Preparation of active antibacterial LDPE surface through multistep physicochemical approach: I. Allylamine grafting, attachment of antibacterial agent and antibacterial activity assessment  

Microsoft Academic Search

Low-density polyethylene (LDPE) samples were treated in air plasma discharge, coated by polyallyamine brush thought copolymeric grafting surface-from reaction and deposited four common antibacterial agents (benzalkonium chloride, bronopol, chlorhexidine and triclosan) to gain material with active antibacterial properties. Surface characteristics were evaluated by static contact angle measurement with surface energy evaluation ATR-FTIR, X-ray Photoelectron Spectroscopy (XPS) and SEM analysis. Inhibition

František Bílek; Tá?a K?ížová; Marián Lehocký

2011-01-01

369

Comparison of the d-Glutamate-Adding Enzymes from Selected Gram-Positive and Gram-Negative Bacteria  

PubMed Central

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 to homogeneity by affinity to amylose resin. Proteolytic treatments of the fusion proteins with factor Xa regenerated the individual MurD proteins. It was found that these fusion proteins retain d-glutamate-adding activity and have Km and Vmax values similar to those of the regenerated MurDs, except for the H. influenzae enzyme. Substrate inhibition by UDP-N-acetylmuramyl-l-alanine, the acceptor substrate, was observed at concentrations greater than 15 and 30 ?M for E. coli and H. influenzae MurD, respectively. Such substrate inhibition was not observed with the E. faecalis and S. aureus enzymes, up to a substrate concentration of 1 to 2 mM. In addition, the two MurDs of gram-negative origin were shown to require monocations such as NH4+ and/or K+, but not Na+, for optimal activity, while anions such as Cl? and SO42? had no effect on the enzyme activities. The activities of the two MurDs of gram-positive origin, on the other hand, were not affected by any of the ions tested. All four enzymes required Mg2+ for the ligase activity and exhibited optimal activities around pH 8. These differences observed between the gram-positive and gram-negative MurDs indicated that the two gram-negative bacteria may apply a more stringent regulation of cell wall biosynthesis at the early stage of peptidoglycan biosynthesis pathway than do the two gram-positive bacteria. Therefore, the MurD-catalyzed reaction may constitute a fine-tuning step necessary for the gram-negative bacteria to optimally maintain its relatively thin yet essential cell wall structure during all stages of growth.

Walsh, Ann W.; Falk, Paul J.; Thanassi, Jane; Discotto, Linda; Pucci, Michael J.; Ho, Hsu-Tso

1999-01-01

370

Comparison of the D-glutamate-adding enzymes from selected gram-positive and gram-negative bacteria.  

PubMed

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 to homogeneity by affinity to amylose resin. Proteolytic treatments of the fusion proteins with factor Xa regenerated the individual MurD proteins. It was found that these fusion proteins retain D-glutamate-adding activity and have Km and Vmax values similar to those of the regenerated MurDs, except for the H. influenzae enzyme. Substrate inhibition by UDP-N-acetylmuramyl-L-alanine, the acceptor substrate, was observed at concentrations greater than 15 and 30 microM for E. coli and H. influenzae MurD, respectively. Such substrate inhibition was not observed with the E. faecalis and S. aureus enzymes, up to a substrate concentration of 1 to 2 mM. In addition, the two MurDs of gram-negative origin were shown to require monocations such as NH4+ and/or K+, but not Na+, for optimal activity, while anions such as Cl- and SO4(2-) had no effect on the enzyme activities. The activities of the two MurDs of gram-positive origin, on the other hand, were not affected by any of the ions tested. All four enzymes required Mg2+ for the ligase activity and exhibited optimal activities around pH 8. These differences observed between the gram-positive and gram-negative MurDs indicated that the two gram-negative bacteria may apply a more stringent regulation of cell wall biosynthesis at the early stage of peptidoglycan biosynthesis pathway than do the two gram-positive bacteria. Therefore, the MurD-catalyzed reaction may constitute a fine-tuning step necessary for the gram-negative bacteria to optimally maintain its relatively thin yet essential cell wall structure during all stages of growth. PMID:10464212

Walsh, A W; Falk, P J; Thanassi, J; Discotto, L; Pucci, M J; Ho, H T

1999-09-01

371

Antibacterial activity in the hemolymph of myriapods (Arthropoda).  

PubMed

The hemolymphs of two diplopod (Chicobolus sp. and Rhapidostreptus virgator) and two chilopod species (Lithobius forficatus and Scolopendra cingulata) were tested for the presence of antibacterial substances using Petri dish tests. The native hemolymph of all species had substances acting on living Micrococcus luteus, whereas only Rhapidostreptus, Scolopendra, and Lithobius were effective against lyophilized Micrococcus. The antibacterial activity against living Micrococcus increased after inoculation with bacteria (Enterobacter cloacae beta-12) in Chicobolus and Rhapidostreptus and also against lyophilized Micrococcus in the latter. Thus, these effects appear to be inducible. None of the myriapods tested had any bacteriostatic effect on Escherichia coli D-31 whereas the growth of gram-negative E. cloacae was inhibited. The antibacterial substances in the diplopod species were unstable when heated but were resistant to freezing. At least two antibacterial substances (a lysozyme-like one and another substance) are considered to occur in Myriapoda. PMID:2273286

Xylander, W E; Nevermann, L

1990-09-01

372

The antibacterial activity and stability of acetic acid.  

PubMed

Acetic acid has been shown to have good antibacterial activity against micro-organisms such as Pseudomonas aeruginosa. This study examined the activity against a range of bacterial pathogens and also assessed any reduction in antibacterial activity due to evaporation or inactivation by organic material in dressings. Acetic acid was active at dilutions as low as 0.166% and the activity was not reduced by evaporation nor by inactivation by cotton swabs. Burn injuries are a major problem in countries with limited resources. Acetic acid is an ideal candidate for use in patients who are treated in those parts of the world. PMID:23747099

Fraise, A P; Wilkinson, M A C; Bradley, C R; Oppenheim, B; Moiemen, N

2013-06-07

373

Studies on the antibacterial activity of dodecylglycerol  

SciTech Connect

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 ether bond as compared to esters. In an attempt towards elucidating the mode of action of DDG, the effect of DDG on bacterial lipid metabolism was examined using Streptococcus mutans BHT, a tolerant bacterium. The metabolic fate of the ether was also determined with the use of three radioactive tracers, /sup 14/C-glycerol, /sup 32/Pi, and /sup 14/C-DDG. Treatment of exponentially growing cultures of S. mutans BHI with growth inhibitory concentrations of DDG (10 and 20 ..mu..g/ml) inhibited the incorporation of /sup 14/C-glycerol into lipid. In vivo studies using /sup 14/C-DDG showed that the /sup 14/C-ether was readily incorporated almost exclusively into phosphatidic (PA) and lysophosphatidic (LPA) acids. When cells prelabelled with either /sup 14/C-glycerol or /sup 32/Pi were exposed to 10 and 20 /sup +/g/ml DDG for 2 h, the accumulation of PA and diphosphatidylglycerol (diPG) was greatly stimulated. However, diPG accumulated at the expense of its precursor, glycerol, which greatly decreased. These data suggest that the ether-containing PA inhibits the synthesis of CDP-diglyceride. Moreover, these results clearly demonstrate that DDG functions as a metabolic rather than physical effector, disputing the conventional notion that bactericidal lipids act as detergents, physically dissolving the cellular envelope.

Brissette, J.L.

1985-01-01

374

An examination of the medicinal potential of Scaevola spinescens: Toxicity, antibacterial, and antiviral activities  

PubMed Central

Background: Scaevola spinescens is an endemic Australian native plant with a history of use as a medicinal agent by indigenous Australians. Yet the medicinal bioactivities of this plant are poorly studied. Materials and Methods: S. spinescens solvent extracts were tested for antimicrobial activity, antiviral activity and toxicity in vitro. Results: All extracts displayed antibacterial activity in the disc diffusion assay. The methanol extract proved to have the broadest specificity, inhibiting the growth of 7 of the 14 bacteria tested (50%). The water, ethyl acetate, chloroform, and hexane extracts inhibited the growth of 6 (42.9%), 5 (35.7%), 5 (35.7%), and 4 (28.6%) of the 14 bacteria tested, respectively. S. spinescens methanolic extracts were equally effective against Gram-positive (50%) and Gram-negative bacteria (50%). All other extracts were more effective at inhibiting the growth of Gram-negative bacteria. All extracts also displayed antiviral activity in the MS2 plaque reduction assay with the methanol, water, ethyl acetate, chloroform, and hexane extracts inhibiting 95.2 ± 1.8%, 72.3 ± 6.3%, 82.6 ± 4.5%, 100 ± 0% and 47.7 ± 12.9% of plaque formation, respectively. All S. spinescens extracts were nontoxic in the Artemia fransiscana bioassay with no significant increase in mortality induced by any extract at 24 and 48 h. The only increase in mortality was seen for the water extract at 72 h, although even this extract displayed low toxicity, inducing only 41.7 ± 23.3% mortality. Conclusions: The lack of toxicity of the S. spinescens extracts and their inhibitory bioactivity against bacteria and viruses validate the Australian Aboriginal usage of S. spinescens and indicates its medicinal potential.

Cock, Ian E.; Kukkonen, Liisa

2011-01-01

375

Gene targeting in the Gram-Positive bacterium Lactococcus lactis, using various delta ribozymes.  

PubMed

The trans-acting antigenomic delta ribozyme, isolated from the human hepatitis delta virus, was shown to be highly stable and active in vitro, as well as in mammalian cell lines. However, the stability and gene-targeting competence of this small ribozyme have not been studied previously in bacterial cells. In this paper we describe the use of two variants of the trans-acting antigenomic delta ribozyme targeting the abundant EF-Tu mRNA in the industrially important gram-positive bacterium Lactococcus lactis. These two delta ribozyme variants were expressed at significant levels and were shown to be highly stable in vivo. The half-life of the EF-Tu mRNA was slightly but consistently reduced in the presence of the classical delta ribozymes (7 to 13%). In contrast, delta ribozymes harboring a specific on/off riboswitch (SOFA-delta ribozymes) targeting the same sites on the EF-Tu mRNA considerably reduced the half-life of this mRNA (22 to 47%). The rates of catalysis of the SOFA-delta ribozymes in L. lactis were similar to the rates determined in vitro, showing that this new generation of delta ribozymes was highly efficient in these bacterial cells. Clearly, SOFA-delta ribozymes appear to be an ideal means for development of gene inactivation systems in bacteria. PMID:16391129

Fiola, Karine; Perreault, Jean-Pierre; Cousineau, Benoit

2006-01-01

376

Investigation of antibacterial activity of cotton fabric incorporating nano silver colloid  

Microsoft Academic Search

In this work, silver nanoparticles were prepared by polyol process with microwave heating and incorporated on cotton fabric surfaces. The antibacterial performance of the antibacterial cotton fabric was tested for different concentration of nano-sized silver colloid, contact time germs, and washing times. It was found that antibacterial activity increased with the increasing concentration of nano-sized silver colloid. The antibacterial fabric

Ngo Vo Ke Thanh; Nguyen Thi Phuong Phong

2009-01-01

377

Vancomycin-resistant gram-positive bacteria isolated from human sources.  

PubMed Central

Recent reports of infections with vancomycin-resistant gram-positive bacteria prompted us to study vancomycin-resistant isolates from human sources to characterize the types of bacteria displaying this phenotype. Thirty-six vancomycin-resistant gram-positive isolates, 14 from clinical specimens and 22 from stool samples, were identified. These isolates were tentatively identified as Lactobacillus spp. (25 strains), Leuconostoc spp. (6 strains), and Pediococcus spp. (3 strains) on the basis of morphology and physiological tests. Two isolates of indeterminate morphology could not be unambiguously assigned to a genus. Four isolates of vancomycin-resistant lactobacilli from normally sterile body sites were considered to be clinically significant. Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens. Better methods for distinguishing the various genera in the clinical microbiology laboratory are needed.

Ruoff, K L; Kuritzkes, D R; Wolfson, J S; Ferraro, M J

1988-01-01

378

In vitro antibacterial activities of ethanol extract of iranian propolis (EEIP) against fish pathogenic bacteria (Aeromonas hydrophila, Yersinia ruckeri & Streptococcus iniae)  

PubMed Central

The “in vitro” antibacterial activity of ethanol extract of propolis (EEIP) from Urmia, Iran was investigated against three prevalent species of fish bacterial pathogens including: Aeromonas hydrophila LMG 3770, Yersinia ruckeri LMG 3279 and Streptococcus iniae LMG 14520. In this study two standard susceptibility testing techniques (Micro-broth dilution method and Agar-well diffusion method) were used to evaluation of the antibacterial activity of EEIP against the mentioned micro-organisms. Also the chemical composition of propolis was determined by the method of Gas chromatography-mass spectrometry (GC-MS). Twenty-six compounds were identified by gas chromatography–mass spectrometry analysis. Results showed Chemical composition of EEIP contained significant amounts of flavonoids, Sesquiterpenes – mainly Eudesmol and Caryophyllene oxide - aromatic acid, and low amounts of aldehydes and triterpens. Furthermore the ethanol extract of propolis inhibited the growth of all examined micro-organisms with the highest antimicrobial activity against Gram-positive bacteria Streptococcus iniae. Ethanol did not influence the antimicrobial effect of EEIP. These antibacterial properties would warrant further studies on the clinical applications of propolis in aquaculture field.

Tukmechi, Amir; Ownagh, Abdolghaffar; Mohebbat, Ali

2010-01-01

379

Antibacterial action of chitosan  

Microsoft Academic Search

The antibacterial action of chitosan hydroglutamate (CH), chitosan lactate (CL) and chitosan derived from fungal mycelia was examined against both gram?negative and gram?positive bacteria. Plate counts indicated inactivation rates of one? to five?log?cycles within one hour. Fungal chitosan had significantly less antibiotic effect than CH and CL. The antibacterial action of CH and CL was very similar and shown to

N. R. Sudarshan; D. G. Hoover; D. Knorr

1992-01-01

380

Novel Antibacterial Class  

PubMed Central

We report the discovery and characterization of a novel ribosome inhibitor (NRI) class that exhibits selective and broad-spectrum antibacterial activity. Compounds in this class inhibit growth of many gram-positive and gram-negative bacteria, including the common respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis, and are nontoxic to human cell lines. The first NRI was discovered in a high-throughput screen designed to identify inhibitors of cell-free translation in extracts from S. pneumoniae. The chemical structure of the NRI class is related to antibacterial quinolones, but, interestingly, the differences in structure are sufficient to completely alter the biochemical and intracellular mechanisms of action. Expression array studies and analysis of NRI-resistant mutants confirm this difference in intracellular mechanism and provide evidence that the NRIs inhibit bacterial protein synthesis by inhibiting ribosomes. Furthermore, compounds in the NRI series appear to inhibit bacterial ribosomes by a new mechanism, because NRI-resistant strains are not cross-resistant to other ribosome inhibitors, such as macrolides, chloramphenicol, tetracycline, aminoglycosides, or oxazolidinones. The NRIs are a promising new antibacterial class with activity against all major drug-resistant respiratory pathogens.

Dandliker, Peter J.; Pratt, Steve D.; Nilius, Angela M.; Black-Schaefer, Candace; Ruan, Xiaoan; Towne, Danli L.; Clark, Richard F.; Englund, Erika E.; Wagner, Rolf; Weitzberg, Moshe; Chovan, Linda E.; Hickman, Robert K.; Daly, Melissa M.; Kakavas, Stephan; Zhong, Ping; Cao, Zhensheng; David, Caroline A.; Xuei, Xiaoling; Lerner, Claude G.; Soni, Niru B.; Bui, Mai; Shen, Linus L.; Cai, Yingna; Merta, Philip J.; Saiki, Anne Y. C.; Beutel, Bruce A.

2003-01-01

381

Novel antibacterial class.  

PubMed

We report the discovery and characterization of a novel ribosome inhibitor (NRI) class that exhibits selective and broad-spectrum antibacterial activity. Compounds in this class inhibit growth of many gram-positive and gram-negative bacteria, including the common respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis, and are nontoxic to human cell lines. The first NRI was discovered in a high-throughput screen designed to identify inhibitors of cell-free translation in extracts from S. pneumoniae. The chemical structure of the NRI class is related to antibacterial quinolones, but, interestingly, the differences in structure are sufficient to completely alter the biochemical and intracellular mechanisms of action. Expression array studies and analysis of NRI-resistant mutants confirm this difference in intracellular mechanism and provide evidence that the NRIs inhibit bacterial protein synthesis by inhibiting ribosomes. Furthermore, compounds in the NRI series appear to inhibit bacterial ribosomes by a new mechanism, because NRI-resistant strains are not cross-resistant to other ribosome inhibitors, such as macrolides, chloramphenicol, tetracycline, aminoglycosides, or oxazolidinones. The NRIs are a promising new antibacterial class with activity against all major drug-resistant respiratory pathogens. PMID:14638491

Dandliker, Peter J; Pratt, Steve D; Nilius, Angela M; Black-Schaefer, Candace; Ruan, Xiaoan; Towne, Danli L; Clark, Richard F; Englund, Erika E; Wagner, Rolf; Weitzberg, Moshe; Chovan, Linda E; Hickman, Robert K; Daly, Melissa M; Kakavas, Stephan; Zhong, Ping; Cao, Zhensheng; David, Caroline A; Xuei, Xiaoling; Lerner, Claude G; Soni, Niru B; Bui, Mai; Shen, Linus L; Cai, Yingna; Merta, Philip J; Saiki, Anne Y C; Beutel, Bruce A

2003-12-01

382

Nanosilver on nanostructured silica: Antibacterial activity and Ag surface area  

PubMed Central

Nanosilver is one of the first nanomaterials to be closely monitored by regulatory agencies worldwide motivating research to better understand the relationship between Ag characteristics and antibacterial activity. Nanosilver immobilized on nanostructured silica facilitates such investigations as the SiO2 support hinders the growth of nanosilver during its synthesis and, most importantly, its flocculation in bacterial suspensions. Here, such composite Ag/silica nanoparticles were made by flame spray pyrolysis of appropriate solutions of Ag-acetate or Ag-nitrate and hexamethyldisiloxane or tetraethylorthosilicate in ethanol, propanol, diethylene glucolmonobutyl ether, acetonitrile or ethylhexanoic acid. The effect of solution composition on nanosilver characteristics and antibacterial activity against the Gram negative Escherichia coli was investigated by monitoring their recombinantly synthesized green fluorescent protein. Suspensions with identical Ag mass concentration exhibited drastically different antibacterial activity pointing out that the nanosilver surface area concentration rather than its mass or molar or number concentration determine best its antibacterial activity. Nanosilver made from Ag-acetate showed a unimodal size distribution, while that made from inexpensive Ag-nitrate exhibited a bimodal one. Regardless of precursor composition or nanosilver size distribution, the antibacterial activity of nanosilver was correlated best with its surface area concentration in solution.

Sotiriou, Georgios A.; Teleki, Alexandra; Camenzind, Adrian; Krumeich, Frank; Meyer, Andreas; Panke, Sven; Pratsinis, Sotiris E.

2013-01-01

383

Leaving home ain't easy: protein export systems in Gram-positive bacteria.  

PubMed

Transport of proteins into or across biological membranes is catalyzed by membrane-bound transport machineries. In Gram-positive bacteria, the vast majority of proteins are exported out of the cytosol by the conserved general secretion (Sec) system or, alternatively, by the twin-arginine translocation (Tat) system, that closely resemble their well-studied counterparts in Gram-negative bacteria. Besides these common major export routes, additional unique protein export systems (such as accessory Sec2 systems and/or type VII/WXG100 secretion systems) exist in some Gram-positive bacteria that are specifically involved in the secretion of limited subsets of proteins. PMID:23541477

Freudl, Roland

2013-03-26

384

Antibacterial and Antifungal Activities of Nitroxoline Mannich Bases  

Microsoft Academic Search

The in vitro activity of nitroxoline and its Mannich bases against bacteria and fungi was investigated. Nitroxoline and its derivative with diisopropylamine as an amino component, exhibited the highest antimicrobial activity. The optimum hydro\\/lipophilic properties (log P), both for antibacterial and antifungal activity, are about log P values of 2. The least effective compound was this nitroxoline Mannich base which

D. Maysinger; M. Movrin

1980-01-01

385

Antibacterial activity of rhodium, iridium, and ruthenium tripodal phosphine complexes.  

PubMed

Twenty-eight rhodium, iridium, or ruthenium complexes were evaluated for their in vitro antibacterial activity against Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922 and Pseudomonaa aeruginosa ATCC 27853. Ten compounds showed an antibacterial activity against Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 29213 with a range of the minimum inhibitory concentrations (MICs) between 16 and 125 micrograms/ml. None of the compounds exhibited antimicrobial activity against the gram-negative strains E. coli ATCC 25922 or Pseudomonas aeruginosa ATCC 29213 with a concentration range between 4 and 500 micrograms/ml. PMID:9553688

Sülü, M; Küçükbay, H; Durmaz, R; Günal, S

1998-03-01

386

Antibacterial Activities of Rhodamine B-Conjugated Gelsolin-Derived Peptides Compared to Those of the Antimicrobial Peptides Cathelicidin LL37, Magainin II, and Melittin  

PubMed Central

The growing number of antibiotic-resistant bacteria necessitates the search for new antimicrobial agents and the principles by which they work. We report that cell membrane-permeant rhodamine B (RhB)-conjugated peptides based on the phosphatidylinositol-4,5-bisphosphate binding site of gelsolin can kill the gram-negative organisms Escherichia coli and Pseudomonas aeruginosa and the gram-positive organism Streptococcus pneumoniae. RhB linkage to the QRLFQVKGRR sequence in gelsolin was essential for the antibacterial function, since the unconjugated peptide had no effect on the bacteria tested. Because RhB-QRLFQVKGRR (also termed PBP10), its scrambled sequence (RhB-FRVKLKQGQR), and PBP10 synthesized from d-isomer amino acids show similar antibacterial properties, the physical and chemical properties of these derivatives appear to be more important than specific peptide folding for their antibacterial functions. The similar activities of PBP10 and all-d-amino-acid PBP10 also indicate that a specific interaction between RhB derivatives and bacterial proteins is unlikely to be involved in the bacterial killing function of PBP10. By using a phospholipid monolayer system, we found a positive correlation between the antibacterial function of PBP10, as well as some naturally occurring antibacterial peptides, and the intrinsic surface pressure activity at the hydrophobic-hydrophilic interface. Surprisingly, we observed little or no dependence of the insertion of these peptides into lipid monolayers on the phospholipid composition. These studies show that an effective antimicrobial agent can be produced from a peptide sequence with specificity to a phospholipid not found in bacteria, and comparisons with other antimicrobial agents suggest that the surface activities of these peptides are more important than specific binding to bacterial proteins or lipids for their antimicrobial functions.

Bucki, Robert; Pastore, Jennifer J.; Randhawa, Paramjeet; Vegners, Rolands; Weiner, Daniel J.; Janmey, Paul A.

2004-01-01

387

Preparation, characterization, and antibacterial activity of ?-irradiated silver nanoparticles in aqueous gelatin  

NASA Astrophysics Data System (ADS)

Colloidal silver nanoparticles (Ag-NPs) were obtained through ?-irradiation of aqueous solutions containing AgNO3 and gelatin as a silver source and stabilizer, respectively. The absorbed dose of ?-irradiation influences the particle diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) and transmission electron microscopy (TEM) images. When the ?-irradiation dose was increased (from 2 to 50 kGy), the mean particle size was decreased continuously as a result of ?-induced Ag-NPs fragmentation. The antibacterial properties of the Ag-NPs were tested against Methicillinresistant Staphylococcus aureus (MRSA) (Gram-positive) and Pseudomonas aeruginosa (P.a) (Gram-negative) bacteria. This approach reveals that the ?-irradiation-mediated method is a promising simple route for synthesizing highly stable Ag-NPs in aqueous solutions with good antibacterial properties for different applications.

Darroudi, Majid; Ahmad, Mansor B.; Hakimi, Mohammad; Zamiri, Reza; Zak, Ali Khorsand; Hosseini, Hasan Ali; Zargar, Mohsen

2013-04-01

388

Co-grafting of amino-poly(ethylene glycol) and Magainin I on a TiO2 surface: tests of antifouling and antibacterial activities.  

PubMed

An antimicrobial peptide, Magainin I (Mag), was grafted to a titanium oxide surface, via an antiadhesive poly(ethylene glycol) (PEG) cross-linker. The latter plays a 2-fold part, being antiadhesive, and enabling the covalent immobilization of the peptide. The functionalization was characterized at each step by reflection absorption infrared spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS). The antiadhesive properties of PEG, and antibacterial activity of the anchored Magainin I, were individually tested toward adsorption of bovin serum albumin (BSA) proteins, and against Gram positive bacteria, Listeria ivanovii , respectively. The results reveal that adhesion of both proteins and bacteria have been considerably reduced, accompanied by an inhibition of the growth of remaining adhered bacteria. This work thus offers a novel approach to functionalize oxide surfaces against biofilms and to measure the so-obtained properties in each of the successive steps of a biofilm formation. PMID:22989370

Peyre, Jessie; Humblot, Vincent; Méthivier, Christophe; Berjeaud, Jean-Marc; Pradier, Claire-Marie

2012-11-15

389

Antibacterial activity of montmorillonites modified with silver  

Microsoft Academic Search

The antibacterial properties of silver modified montmorillonites from Pellegrini Lake, Argentina were tested in growth inhibition of Escherichia coli bacteria. Montmorillonite was first submitted to different treatments: (a) calcination at 550°C for 3h and (b) grinding during 300s. After that, the samples were loaded with silver by ion exchange. Structural characterization was performed by X-ray diffraction (XRD), Fourier transformed infrared

S. M. Magaña; P. Quintana; D. H. Aguilar; J. A. Toledo; C. Ángeles-Chávez; M. A. Cortés; L. León; Y. Freile-Pelegrín; T. López; R. M. Torres Sánchez

2008-01-01

390

Polyphenolic composition, antioxidant and antibacterial activities for two Romanian subspecies of Achillea distans Waldst. et Kit. ex Willd.  

PubMed

The aim of this work was to study the chemical composition, antioxidant and antibacterial properties of Achillea distans Waldst. et Kit. subsp. distans and Achillea distans Waldst. et Kit. subsp. alpina Rochel, from the Rodna Mountains (Romania). The identification and quantification of major phenolic compounds was performed by a HPLC-MS method. The total polyphenolic and flavonoid content was determined spectrophotometrically. The antioxidant activity was evaluated using the DPPH bleaching method, trolox equivalent antioxidant capacity assay (TEAC), hemoglobin ascorbate peroxidase activity inhibition (HAPX) assay, and an Electron Paramagnetic Resonance (EPR) spectroscopy method. A data indicated that A. distans subsp. alpina extract has more antioxidant activity than A. distans subsp. distans extract. Luteolin, apigenin, quercetin, caffeic and chlorogenic acids were present in the two extracts of A. distans, but in different amounts. Three flavonoids were detected only in A. distans subsp. alpina. The polyphenol-richer A. distans subsp. alpina extract showed a higher antioxidant activity than A. distans subsp. distans extract. A. distans subsp. distans extract showed inhibitory activity for Gram-positive bacteria, as evaluated with four species. The quantitative and qualitative differences between the two subspecies of Achillea distans could be used as a potential taxonomic marker in order to distinguish the species. PMID:23887715

Benedec, Daniela; Vlase, Laurian; Oniga, Ilioara; Mot, Augustin C; Damian, Grigore; Hanganu, Daniela; Duma, Mihaela; Silaghi-Dumitrescu, Radu

2013-07-24

391

Vancomycin-resistant Gram-positive bacterial endophthalmitis: epidemiology, treatment options, and outcomes  

PubMed Central

Background The purpose of this study is to evaluate the microbiological profile and treatment outcomes of vancomycin-resistant Gram-positive bacterial endophthalmitis. Medical records of all patients with Gram-positive bacterial endophthalmitis resistant to vancomycin presenting between 1 January 2005 and 31 December 2010 were reviewed in this noncomparative, consecutive, retrospective case series. Favorable outcome was defined as a best-corrected visual acuity of ?20/200. Results Out of 682 culture-positive endophthalmitis isolates, 448/682 (65.6%) were associated with Gram-positive bacteria. In vitro resistance to vancomycin was noted in 7/448 (1.56%). Three cases were posttraumatic, three were postoperative, and one was endogenous in origin. Four Bacillus isolates, two Staphylococcus isolates, and an Enterococcus isolate were resistant. Isolates resistant to vancomycin were sensitive in vitro to ciprofloxacin in 6/7 (86%) patients. Presenting visual acuity was light perception in all seven cases. Favorable outcome was achieved in only 1/7 (14.3%) cases. Conclusions Vancomycin-resistant endophthalmitis is uncommon and usually associated with poor visual outcome. Bacillus sp. is the most frequent Gram-positive bacteria resistant to vancomycin. Fluoroquinolones like ciprofloxacin may be considered as a useful alternative in vancomycin-resistant endophthalmitis.

2013-01-01

392

Construction and evaluation of multisite recombinatorial (Gateway) cloning vectors for Gram-positive bacteria  

PubMed Central

Background The Gateway recombinatorial cloning system allows easy and rapid joining of DNA fragments. Here we report the construction and evaluation of three different Gram-positive vectors that can be used with the Multisite Gateway cloning system to rapidly produce new gene arrangements in plasmid constructs for use in a variety of Gram-positive bacteria. Results Comparison of patterns of reporter gene expression with conventionally constructed clones show that the presence of residual recombination (att) sites does not have an effect on patterns of gene expression, although overall levels of gene expression may vary. Rapid construction of these new vectors allowed vector/gene combinations to be optimized following evaluation of plasmid constructs in different bacterial cells and demonstrates the benefits of plasmid construction using Gateway cloning. Conclusion The residual att sites present after Gateway cloning did not affect patterns of promoter induction in Gram-positive bacteria and there was no evidence of differences in mRNA stability of transcripts. However overall levels of gene expression may be reduced, possibly due to some post-transcriptional event. The new vectors described here allow faster, more efficient cloning in range of Gram-positive bacteria.

Perehinec, Tania M; Qazi, Saara NA; Gaddipati, Sanyasi R; Salisbury, Vyvyan; Rees, Catherine ED; Hill, Philip J

2007-01-01

393

Comparative analysis of gene expression among low G+C gram-positive genomes  

Microsoft Academic Search

We present a comparative analysis of predicted highly expressed (PHX) genes in the low G+C Gram-positive genomes of Bacillus subtilis, Bacillus halodurans, Listeria monocytogenes, Listeria innocua, Lactococcus lactis, Streptococcus pyogenes, Streptococcus pneumoniae, Staphylococcus aureus, Clostridium acetobutylicum, and Clostridium perfringens. Most enzymes acting in glycolysis and fermentation pathways are PHX in these genomes, but not those involved in the TCA cycle

Samuel Karlin; Julie Theriot; Jan Mrázek

2004-01-01

394

Polyhydroxyalkanoates in Gram-positive bacteria: insights from the genera Bacillus and Streptomyces  

Microsoft Academic Search

Gram-positive bacteria, notably Bacillus and Streptomyces, have been used extensively in industry. However, these microorganisms have not yet been exploited for the production of the biodegradable polymers, polyhydroxyalkanoates (PHAs). Although PHAs have many potential applications, the cost of production means that medical applications are currently the main area of use. Gram-negative bacteria, currently the only commercial source of PHAs, have

Sabeel P. Valappil; Aldo R. Boccaccini; Christopher Bucke; Ipsita Roy

2007-01-01

395

Poreforming bacteriocins of Gram-positive bacteria and self-protection mechanisms of producer organisms  

Microsoft Academic Search

Proteinaceous antimicrobial compounds are produced by a diversity of species ranging from bacteria to humans. This review focuses on the mode of action of pore-forming bacteriocins produced by Gram-positive bacteria. The mechanism of action of specific immunity proteins, which protect the producer strains from the lethal action of their own products (producer self-protection), are also discussed.

Tjakko Abee

1995-01-01

396

Peritonitis due to uncommon gram-positive pathogens in children undergoing peritoneal dialysis  

PubMed Central

Peritonitis is still the main complication of peritoneal dialysis (PD) in children. Staphylococcus, especially Staphylococcus epidermidis and Staphylococcus aureus, are the predominant species isolated, followed by Streptococcus spp. and by far by gram-negative bacteria and fungi. We describe three cases of PD-related peritonitis in pediatric patients due to uncommon gram-positive pathogens, which were treated with intraperitoneal antibiotic agents.

Dotis, J; Printza, N; Papachristou, F

2012-01-01

397

Small molecule inhibitor of lipoteichoic acid synthesis is an antibiotic for Gram-positive bacteria  

PubMed Central

The current epidemic of infections caused by antibiotic-resistant Gram-positive bacteria requires the discovery of new drug targets and the development of new therapeutics. Lipoteichoic acid (LTA), a cell wall polymer of Gram-positive bacteria, consists of 1,3-polyglycerol-phosphate linked to glycolipid. LTA synthase (LtaS) polymerizes polyglycerol-phosphate from phosphatidylglycerol, a reaction that is essential for the growth of Gram-positive bacteria. We screened small molecule libraries for compounds inhibiting growth of Staphylococcus aureus but not of Gram-negative bacteria. Compound 1771 [2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-naphtho[2,1-b]furan-1-ylacetate] blocked phosphatidylglycerol binding to LtaS and inhibited LTA synthesis in S. aureus and in Escherichia coli expressing ltaS. Compound 1771 inhibited the growth of antibiotic-resistant Gram-positive bacteria and prolonged the survival of mice with lethal S. aureus challenge, validating LtaS as a target for the development of antibiotics.

Richter, Stefan G.; Elli, Derek; Kim, Hwan Keun; Hendrickx, Antoni P. A.; Sorg, Joseph A.; Schneewind, Olaf; Missiakas, Dominique

2013-01-01

398

Transformations of the gram-positive honey bee pathogen, Paenibacillus larvae, by electroporation  

Technology Transfer Automated Retrieval System (TEKTRAN)

In this study we developed an electrotransformation method for use with the Gram-positive bacterium Paenibacillus larvae—a deadly pathogen of honey bees. The method is substantially different from the only other electroporation method for a Paenibacillus species found in the literature. Using the ty...

399

Novel Cassette-Based Shuttle Vector System for Gram-Positive Bacteria  

Microsoft Academic Search

Virulent bacterial strains have developed complex metabolic and regulatory pathways to enable them to thrive in the in vivo environment during infection. Understanding how the regula- tory networks operate requires manipulation of many genes and expressing them temporally and spatially at different levels or under separate regulatory controls. In the case of gram- positive bacteria including staphylococci, the introduction of

Emmanuelle Charpentier; Ana I. Anton; Peter Barry; Berenice Alfonso; Yuan Fang; Richard P. Novick

2004-01-01

400

Genome-Wide Gene Order Distances Support a United Gram-Positive Bacteria  

NASA Astrophysics Data System (ADS)

We have attempted to use a Monte Carlo approach to look for small genome-wide instances of gene order conservation. Our trees show the actinobacteria as a sister group to the bulk of the firmicutes. The results are supportive of a single origin for the gram-positive cell.

House, C. H.; Fitz-Gibbon, S. T.

2010-04-01

401

Anchorless adhesins and invasins of Gram-positive bacteria: a new class of virulence factors  

Microsoft Academic Search

Bacterial adherence to and invasion of eukaryotic cells are important mechanisms of pathogenicity. Most Gram-positive bacteria interact with the components of the host extracellular matrix (ECM) to adhere to, colonize and invade cells and tissues. The bacterial proteins that bind to components of the ECM harbour signal sequences for their secretion and mechanisms of anchoring to the host cell surface.

Gursharan S Chhatwal

2002-01-01

402

Protein phosphorylation and regulation of carbon metabolism in Gram-negative versus Gram-positive bacteria  

Microsoft Academic Search

Bacteria impose regulatory mechanisms on metabolic processes to ensure that the needs of the cell are met but not exceeded. Here, we discuss the basic features of a mechanism by which carbohydrate catabolism in Gram-positive bacteria is regulated. Although the physiological consequences of this regulation are the same as in Gram-negative bacteria, the mechanism is entirely different. These regulatory processes

Milton H Saier; Sylvie Chauvaux; Josef Deutscher; Jonathan Reizer; Jing-Jing Ye

1995-01-01

403

Expression systems for industrial Gram-positive bacteria with low guanine and cytosine content  

Microsoft Academic Search

Recent years have seen an increase in the development of gene expression systems for industrial Gram-positive bacteria with low guanine and cytosine content that belong to the genera Bacillus, Clostridium, Lactococcus, Lactobacillus, Staphylococcus and Streptococcus. In particular, considerable advances have been made in the construction of inducible gene expression systems based on the capacity of these bacteria to utilize specific

Willem M. de Vos; Michiel Kleerebezem; Oscar P. Kuipers

1997-01-01

404

Microarray-Based Detection of 90 Antibiotic Resistance Genes of Gram-Positive Bacteria  

Microsoft Academic Search

A disposable microarray was developed for detection of up to 90 antibiotic resistance genes in gram-positive bacteria by hybridization. Each antibiotic resistance gene is represented by two specific oligonucleotides chosen from consensus sequences of gene families, except for nine genes for which only one specific oligonucleotide could be developed. A total of 137 oligonucleotides (26 to 33 nucleotides in length

Vincent Perreten; Lorianne Vorlet-Fawer; Peter Slickers; Ralf Ehricht; Peter Kuhnert; Joachim Frey

2005-01-01

405

Sorting sortases: a nomenclature proposal for the various sortases of Gram-positive bacteria  

Microsoft Academic Search

Bacterial surface proteins constitute a diverse group of molecules with important functions, such as adherence, invasion, signaling and interaction with the host immune system or the environment. In Gram-positive bacteria, many surface proteins are anchored to the cell wall envelope by an enzyme named sortase, which recognizes a conserved carboxylic sorting motif. The sequence of the prototype staphylococcal SrtA has

Shaynoor Dramsi; Patrick Trieu-Cuot; Hélène Bierne

2005-01-01

406

Gram-positive three-component antimicrobial peptide-sensing system  

Microsoft Academic Search

To survive during colonization or infection of the human body, microorganisms must circumvent mechanisms of innate host defense. Antimicrobial peptides represent a key component of innate host defense, especially in phagocytes and on epithelial surfaces. However, it is not known how the clinically important group of Gram-positive bacteria sense antimicrobial peptides to coordinate a directed defensive response. By determining the

Min Li; Yuping Lai; A. E. Villaruz; D. J. Cha; D. E. Sturdevant; Michael Otto

2007-01-01

407

Synthesis and evaluation of antibacterial activities of andrographolide analogues  

Microsoft Academic Search

Andrographolide (Andro), the main active component of the herb Andrographis paniculata, has been used for many years to treat a variety of diseases including bacterial and viral infections. Andro was recently reported to act by inhibiting the bacterial quorum sensing system. We have synthesized several Andro analogues and investigated their antibacterial activity and mechanism of action. The new compounds were

Xiaojian Jiang; Pei Yu; Jie Jiang; Zaijun Zhang; Zhongli Wang; Zhaoqi Yang; Zhiming Tian; Susan C. Wright; James W. Larrick; Yuqiang Wang

2009-01-01

408