scholarly journals Lysophosphatidylcholine Potentiates Antibacterial Activity of Polymyxin B

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Jitender Yadav ◽  
Sana Ismaeel ◽  
Ayub Qadri
Keyword(s):  
Antibacterial Activity ◽  
Polymyxin B ◽  
Resistant Bacteria ◽  
Bacterial Membrane ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Drug Resistant Bacteria

ABSTRACT Polymyxin B, used to treat infections caused by antibiotic-resistant Gram-negative bacteria, produces nephrotoxicity at its current dosage. We show that a combination of nonbactericidal concentration of this drug and lysophosphatidylcholine (LPC) potently inhibits growth of Salmonella and at least two other Gram-negative bacteria in vitro. This combination makes bacterial membrane porous and causes degradation of DnaK, the regulator of protein folding. Polymyxin B-LPC combination may be an effective and safer regimen against drug-resistant bacteria.

scholarly journals Battacin (Octapeptin B5), a New Cyclic Lipopeptide Antibiotic from Paenibacillus tianmuensis Active against Multidrug-Resistant Gram-Negative Bacteria

2011 ◽  
Vol 56 (3) ◽  
pp. 1458-1465 ◽  
Author(s):  
Chao-Dong Qian ◽  
Xue-Chang Wu ◽  
Yi Teng ◽  
Wen-Peng Zhao ◽  
Ou Li ◽  
...  
Keyword(s):  
Polymyxin B ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Content Type ◽  
Lipopeptide Antibiotic

ABSTRACTHospital-acquired infections caused by drug-resistant bacteria are a significant challenge to patient safety. Numerous clinical isolates resistant to almost all commercially available antibiotics have emerged. Thus, novel antimicrobial agents, specifically those for multidrug-resistant Gram-negative bacteria, are urgently needed. In the current study, we report the isolation, structure elucidation, and preliminary biological characterization of a new cationic lipopeptide antibiotic, battacin or octapeptin B5, produced from aPaenibacillus tianmuensissoil isolate. Battacin kills bacteriain vitroand has potent activity against Gram-negative bacteria, including multidrug-resistant and extremely drug-resistant clinical isolates. Hospital strains ofEscherichia coliandPseudomonas aeruginosaare the pathogens most sensitive to battacin, with MICs of 2 to 4 μg/ml. The ability of battacin to disrupt the outer membrane of Gram-negative bacteria is comparable to that of polymyxin B, the last-line therapy for infections caused by antibiotic-resistant Gram-negative bacteria. However, the capacity of battacin to permeate bacterial plasma membranes is less extensive than that of polymyxin B. The bactericidal kinetics of battacin correlate with the depolarization of the cell membrane, suggesting that battacin kills bacteria by disrupting the cytoplasmic membrane. Other studies indicate that battacin is less acutely toxic than polymyxin B and has potentin vivobiological activity againstE. coli. Based on the findings of the current study, battacin may be considered a potential therapeutic agent for the treatment of infections caused by antibiotic-resistant Gram-negative bacteria.

scholarly journals Trends in the Susceptibility of Clinically Important Resistant Bacteria to Tigecycline: Results from the TigecyclineIn VitroSurveillance in Taiwan Study, 2006 to 2010

2011 ◽  
Vol 56 (3) ◽  
pp. 1452-1457 ◽  
Author(s):  
Yen-Hsu Chen ◽  
Po-Liang Lu ◽  
Cheng-Hua Huang ◽  
Chun-Hsing Liao ◽  
Chin-Te Lu ◽  
...  
Keyword(s):  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Content Type ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
Vancomycin Resistant ◽  
Susceptibility Rate ◽  
Important Drug

ABSTRACTThe TigecyclineIn VitroSurveillance in Taiwan (TIST) study, a nationwide, prospective surveillance during 2006 to 2010, collected a total of 7,793 clinical isolates, including methicillin-resistantStaphylococcus aureus(MRSA) (n= 1,834), penicillin-resistantStreptococcus pneumoniae(PRSP) (n= 423), vancomycin-resistant enterococci (VRE) (n= 219), extended-spectrum β-lactamase (ESBL)-producingEscherichia coli(n= 1,141), ESBL-producingKlebsiella pneumoniae(n= 1,330),Acinetobacter baumannii(n= 1,645), andStenotrophomonas maltophilia(n= 903), from different specimens from 20 different hospitals in Taiwan. MICs of tigecycline were determined following the criteria of the U.S. Food and Drug Administration (FDA) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST-2011). Among drug-resistant Gram-positive pathogens, all of the PRSP isolates were susceptible to tigecycline (MIC90, 0.03 μg/ml), and only one MRSA isolate (MIC90, 0.5 μg/ml) and three VRE isolates (MIC90, 0.125 μg/ml) were nonsusceptible to tigecycline. Among the Gram-negative bacteria, the tigecycline susceptibility rates were 99.65% for ESBL-producingE. coli(MIC90, 0.5 μg/ml) and 96.32% for ESBL-producingK. pneumoniae(MIC90, 2 μg/ml) when interpreted by FDA criteria but were 98.7% and 85.8%, respectively, when interpreted by EUCAST-2011 criteria. The susceptibility rate forA. baumannii(MIC90, 4 μg/ml) decreased from 80.9% in 2006 to 55.3% in 2009 but increased to 73.4% in 2010. A bimodal MIC distribution was found among carbapenem-susceptibleA. baumanniiisolates, and a unimodal MIC distribution was found among carbapenem-nonsusceptibleA. baumanniiisolates. In Taiwan, tigecycline continues to have excellentin vitroactivity against several major clinically important drug-resistant bacteria, with the exception ofA. baumannii.

scholarly journals Occurrence of Multiple Antibiotic Resistant Bacteria in Aquatic Environments in Central Minnesota

2015 ◽  
Vol 12 (3) ◽  
Author(s):  
Megan Bollin ◽  
Ellen Jensen ◽  
David Mitchell
Keyword(s):  
Aquatic Ecosystems ◽  
Resistant Bacteria ◽  
Aquatic Environments ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Density Values ◽  
Resistance Coefficients

The purpose of this study was to investigate the possibility that antibiotic resistant bacteria could be isolated and identified in aquatic ecosystems in the lakes on the campus of Saint John’s University and the nearby Sauk and Watab Rivers. A total of 125 isolates were collected. Seventy-nine percent of the isolates were gram negative rods. Twenty-six isolates that were resistant to seven or more antibiotics were selected for further investigation. The 26 isolates were all gram negative and members of seven different genera with Flavobacterium and Acinetobacter being the most common. Resistance coefficients were calculated based on optical density values relative to cells grown without antibiotics. Multi-drug resistant, gram negative bacteria were shown to be common in aquatic environments in central Minnesota.

scholarly journals Mechanistic Study of Synergistic Antimicrobial Effects between Poly (3-hydroxybutyrate) Oligomer and Polyethylene Glycol

2020 ◽  
Author(s):  
Ziheng Zhang ◽  
Jun Li ◽  
Linlin Ma ◽  
Xingxing Yang ◽  
Bin Fei ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Antimicrobial Agents ◽  
Antimicrobial Effect ◽  
Mechanistic Study ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Drug Resistant Bacteria

We reported previously that poly (3-hydroxybutyrate) (PHB) oligomer is an effective antimicrobial agent against gram-positive bacteria, gram-negative bacteria, fungi and multi-drug resistant bacteria. In this work, it was further found that polyethylene glycol (PEG) can promote the antimicrobial effect of PHB oligomer synergistically. Three hypothetic mechanisms were proposed, that is, generation of new antimicrobial components, degradation of PHB macromolecules and dissolution/dispersion of PHB oligomer by PEG. With a series of systematic experiments and characterizations of HPLC-MS, it was deducted that dissolution/dispersion of PHB oligomer dominated the synergistic antimicrobial effect between PHB oligomer and PEG. This work demonstrates a way for promoting antimicrobial effect of PHB oligomer and other antimicrobial agents through improving hydrophilicity.

scholarly journals 1,2,4-Oxadiazole/2-Imidazoline Hybrids: Multi-target-directed Compounds for the Treatment of Infectious Diseases and Cancer

2019 ◽  
Vol 20 (7) ◽  
pp. 1699 ◽  
Author(s):  
Anton Shetnev ◽  
Sergey Baykov ◽  
Stanislav Kalinin ◽  
Alexandra Belova ◽  
Vladimir Sharoyko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Efflux Pump ◽  
Ductal Adenocarcinoma ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Drug Resistant Bacteria ◽  
Efflux Pump Inhibitors

Replacement of amide moiety with the 1,2,4-oxadiazole core in the scaffold of recently reported efflux pump inhibitors afforded a novel series of oxadiazole/2-imidazoline hybrids. The latter compounds exhibited promising antibacterial activity on both Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas fluorescens) strains. Furthermore, selected compounds markedly inhibited the growth of certain drug-resistant bacteria. Additionally, the study revealed the antiproliferative activity of several antibacterial frontrunners against pancreas ductal adenocarcinoma (PANC-1) cell line, as well as their type-selective monoamine oxidase (MAO) inhibitory profile.

scholarly journals Exogenous Citrulline and Glutamine Contribute to Reverse the Resistance of Salmonella to Apramycin

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan Yong ◽  
Yanhong Zhou ◽  
Kexin Liu ◽  
Guochang Liu ◽  
Liqin Wu ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Tricarboxylic Acid Cycle ◽  
Animal Health ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Bacterial Cells ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Drug Resistant Bacteria

Antibiotic resistance is an increasing concern for human and animal health worldwide. Recently, the concept of reverting bacterial resistance by changing the metabolic state of antibiotic-resistant bacteria has emerged. In this study, we investigated the reversal of Apramycin resistance in Salmonella. First, non-targeted metabonomics were used to identify key differential metabolites of drug-resistant bacteria. Then, the reversal effect of exogenous substances was verified in vivo and in vitro. Finally, the underlying mechanism was studied. The results showed that the metabolites citrulline and glutamine were significantly reduced in Apramycin-resistant Salmonella. When citrulline and glutamine were added to the culture medium of drug-resistant Salmonella, the killing effect of Apramycin was restored markedly. Mechanistic studies showed that citrulline and glutamine promoted the Tricarboxylic acid cycle, produced more NADH in the bacteria, and increased the proton-motive force, thus promoting Apramycin entry into the bacterial cells, and killing the drug-resistant bacteria. This study provides a useful method to manage infections by antibiotic-resistant bacteria.

scholarly journals Novel Seleno- and Thio-Urea Containing Dihydropyrrol-2-One Analogues as Antibacterial Agents

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 321
Author(s):  
Shekh Sabir ◽  
Tsz Tin Yu ◽  
Rajesh Kuppusamy ◽  
Basmah Almohaywi ◽  
George Iskander ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Positive Bacterium ◽  
Quorum Sensing Inhibition ◽  
Drug Resistant Bacteria

The quorum sensing (QS) system in multi-drug-resistant bacteria such as P. aeruginosa is primarily responsible for the development of antibiotic resistance and is considered an attractive target for antimicrobial drug discovery. In this study, we synthesised a series of novel selenourea and thiourea-containing dihydropyrrol-2-one (DHP) analogues as LasR antagonists. The selenium DHP derivatives displayed significantly better quorum-sensing inhibition (QSI) activities than the corresponding sulphur analogues. The most potent analogue 3e efficiently inhibited the las QS system by 81% at 125 µM and 53% at 31 µM. Additionally, all the compounds were screened for their minimum inhibitory concentration (MIC) against the Gram-positive bacterium S. aureus, and interestingly, only the selenium analogues showed antibacterial activity, with 3c and 3e being the most potent with a MIC of 15.6 µM.

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