Novel Benzoxazoles: Synthesis and Antibacterial, Antifungal, and Antitubercular Activity against Antibiotic-Resistant and -Sensitive Microbes

2013 ◽  
Vol 68 (11-12) ◽  
pp. 453-460 ◽  
Author(s):  
Mustafa Arisoy ◽  
Ozlem Temiz-Arpaci ◽  
Fatma Kaynak-Onurdag ◽  
Selda Ozgen
Keyword(s):  
Escherichia Coli ◽  
Mycobacterium Tuberculosis ◽  
Enterococcus Faecalis ◽  
Antitubercular Activity ◽  
Candida Krusei ◽  
Gram Negative Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Spectrum Activity ◽  
Broad Spectrum Activity

A new series of 5-(p-substituted benzamido/phenylacetamido)-2-(p-tert-butylphenyl)benzoxazole derivatives were synthesized and evaluated for their antibacterial, antifungal, and antimycobacterial activities against antibiotic-resistant and -sensitive Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Mycobacterium tuberculosis as well as against Candida albicans and Candida krusei. The compounds possessed broad-spectrum activity against all of the tested Gram-positive and Gram-negative bacteria and yeasts, their minimum inhibitory concentrations (MICs) ranging between 16 - 128 μg/ml. One compound exhibited significant antibacterial activity (16 μg/ml) against an antibioticresistant Enterococcus faecalis isolate, having twice the potency of the compared standard drugs vancomycin and gentamycin sulfate. The compounds also showed moderate antitubercular activity with MIC values between 8 - 128 μg/ml against Mycobacterium tuberculosis and its clinical isolate.

Survival of some non-starter bacteria in naturally ripened and enzyme-accelerated Cheddar cheese

1988 ◽  
Vol 55 (4) ◽  
pp. 597-602 ◽  
Author(s):  
Lydia Bautista ◽  
Rohan G. Kroll
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Enzyme System ◽  
Cheddar Cheese ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Ripening Period ◽  
Gram Positive Bacteria

SummaryEffects of the addition of a proteinase (Neutrase 1–5S) and a peptidase (aminopeptidase DP-102) as agents for accelerating the ripening of Cheddar cheese on the survival of some non-starter bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coliand aSalmonellasp.) were studied throughout a 4-month ripening period. The enzymes were found to have no significant effect on the survival of the Gram-positive bacteria but some significant effects were observed, at some stages of the ripening period, with the Gram-negative bacteria in that lower levels were recovered from cheeses treated with the enzyme system.

scholarly journals Comparative Effects of Carbapenems on Bacterial Load and Host Immune Response in aKlebsiella pneumoniaeMurine Pneumonia Model

2010 ◽  
Vol 55 (2) ◽  
pp. 836-844 ◽  
Author(s):  
Jamese J. Hilliard ◽  
John L. Melton ◽  
LeRoy Hall ◽  
Darren Abbanat ◽  
Jeffrey Fernandez ◽  
...  
Keyword(s):  
Bacterial Load ◽  
Infection Model ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Tissue Sections ◽  
Time Period ◽  
Infection Treatment ◽  
Spectrum Activity ◽  
Broad Spectrum Activity

ABSTRACTDoripenem is a carbapenem with potent broad-spectrum activity against Gram-negative pathogens, including antibiotic-resistantEnterobacteriaceae. As the incidence of extended-spectrum β-lactamase (ESBL)-producing Gram-negative bacilli is increasing, it was of interest to examine thein vivocomparative efficacy of doripenem, imipenem, and meropenem against aKlebsiella pneumoniaeisolate expressing the TEM-26 ESBL enzyme. In a murine lethal lower respiratory infection model, doripenem reduced theKlebsiellalung burden by 2 log10CFU/g lung tissue over the first 48 h of the infection. Treatment of mice with meropenem or imipenem yielded reductions of approximately 1.5 log10CFU/g during this time period. Seven days postinfection,Klebsiellatiters in the lungs of treated mice decreased an additional 2 log10CFU/g relative to those in the lungs of untreated control animals. Lipopolysaccharide (LPS) endotoxin release assays indicated that 6 h postinfection, meropenem- and imipenem-treated animals had 10-fold more endotoxin in lung homogenates and sera than doripenem-treated mice. Following doripenem treatment, the maximum endotoxin release postinfection (6 h) was 53,000 endotoxin units (EU)/ml, which was 2.7- and 6-fold lower than imipenem or meropenem-treated animals, respectively. While the levels of several proinflammatory cytokines increased in both the lungs and sera following intranasalK. pneumoniaeinoculation, doripenem treatment, but not meropenem or imipenem treatment, resulted in significantly increased interleukin 6 levels in lung homogenates relative to those in lung homogenates of untreated controls, which may contribute to enhanced neutrophil killing of bacteria in the lung. Histological examination of tissue sections indicated less overall inflammation and tissue damage in doripenem-treated mice, consistent with improved antibacterial efficacy, reduced LPS endotoxin release, and the observed cytokine induction profile.

scholarly journals Chitosan Oligosaccharides Coupling Inhibits Bacterial Biofilm-Related Antibiotic Resistance against Florfenicol

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 6043
Author(s):  
Xianghua Yuan ◽  
Jing Liu ◽  
Ruilian Li ◽  
Junlin Zhou ◽  
Jinhua Wei ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Bacterial Infections ◽  
Bacterial Biofilm ◽  
Bacterial Biofilms ◽  
Gram Negative Bacteria ◽  
Planktonic Cells ◽  
Gram Negative ◽  
Chitosan Oligosaccharides ◽  
Spectrum Activity ◽  
Broad Spectrum Activity

The formation of bacterial biofilms has increased the resistance of bacteria to various environmental factors and is tightly associated with many persistent and chronic bacterial infections. Herein we design a strategy conjugating florfenicol, an antibiotic commonly used in the treatment of streptococcus, with the antimicrobial biomaterial, chitosan oligosaccharides. The results demonstrated that the florfenicol-COS conjugate (F-COS) efficiently eradicated the mature Streptococcus hyovaginalis biofilm, apparently inhibiting drug resistance to florfenicol. A quantity of 250 μg/mL F-COS showed effective inhibitory activity against planktonic cells and biofilm of the bacteria, and a 4-fold improvement of the F-COS compared to unmodified florfenicol was observed. Furthermore, the conjugate showed a broad-spectrum activity against both Gram-positive and Gram-negative bacteria. It suggested that F-COS might have a potential for application in the treatment of biofilm-related infections.

scholarly journals Bryndza cheese of Slovak origin as potential resources of probiotic bacteria

10.5219/1413 ◽  
2020 ◽  
Vol 14 ◽  
pp. 641-646
Author(s):  
Miroslava Kačániová ◽  
Petra Borotová ◽  
Margarita Terenjeva ◽  
Simona Kunová ◽  
Soňa Felsöciová ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Klebsiella Pneumoniae ◽  
Enterococcus Faecalis ◽  
Yersinia Enterocolitica ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Bryndza cheese includes several predominant lactic acid bacteria. The aim of our study was the antagonistic effect of lactic acid bacteria supernatant isolated from ewes´ cheese bryndza against ten Gram-positive and Gram-negative bacteria. Isolated strains of bacteria were obtained from bryndza which were produced in five different regions of Slovakia. Isolated strains of lactic acid bacteria were identified with mass spectrometry MALDI-TOF MS Biotyper. A total of one hundred and thirty lactic bacteria include Enterococcus faecalis, Enterococcus faecium, Enterococcus hirae, Lactobacillus brevis, Lactobacillus harbinensis, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus paracasei ssp. paracasei, Lactobacillus paraplantarum, Lactobacillus suebicus, Lactococcus lactis ssp. lactis, Lactococcus lactis, and Pediococcus acidilactici were tested in this study against Gram-negative bacteria: Escherichia coli CCM 3988, Klebsiella pneumoniae CCM 2318, Salmonella enterica subsp. enterica CCM 3807, Shigella sonnei CCM 1373, Yersinia enterocolitica CCM 5671 and Gram-positive bacteria: Bacillus thuringiensis CCM 19, Enterococcus faecalis CCM 4224, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461, Streptococcus pneumonia CCM 4501 with agar diffusion method. Lactic acid bacteria showed activity 92% against Yersinia enterocolitica, 91% against Klebsiella pneumoniae, 88% against Escherichia coli, 84% against Listeria monocytogenes. The most effective bacteria against Gram-positive and Gram-negative bacteria tested was Lactobacillus paracasei ssp. paracasei.

Antimicrobial and cytotoxic activity of Macrophomina phaseolina isolated from gummosis infected citrus reticulata

2013 ◽  
pp. 125-133
Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Brine Shrimp ◽  
Inhibitory Concentration ◽  
Lethal Dose ◽  
Macrophomina Phaseolina ◽  
Chloroform Extract ◽  
Citrus Reticulata ◽  
Gram Negative Bacteria ◽  
Gram Negative

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

scholarly journals MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa

2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Cell Division ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Active Efflux

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

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