Quinolone antibacterials are one of the most important classes of pharmacological agents known as potent inhibitors of bacterial DNA gyrase and topoisomerase IV that efficiently inhibit DNA replication and transcription by generating several double-stranded DNA break. Some quinolone derivatives demonstrated inhibitory potential against eukaryote topoismarase II and substantial dose-dependent cy...

In Reply to Helms: In the article by Helms et al., Helms concludes that infections with Salmonella Typhimurium strains resistant to ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline (hereafter referred to as penta-resistant) were associated with higher death rates than infections with non–penta-resistant S. Typhimurium. Helms also concluded that infections with quinolone-...

Background: Plasmid-mediated quinolone resistance (PMQR) determinants are commonly characterized in Klebsiella pneumoniae isolates worldwide and complicate the treatment of infections caused by this bacterium. Objectives: This study aimed to investigate prevalence PMQR molecular typing blood K. Milad hospital Tehran, Iran, within 2018 - 2019. Methods: A total 100 were tested for susceptibility ...

BACKGROUND Publicly-funded drug plans often use prior authorization policies to limit drug prescribing. To guide physician prescribing of a class of antibiotics with broad antimicrobial activity (quinolone antibiotics) in accordance with new prescribing guidelines, Alberta's provincial health ministry implemented a new mechanism for formulary restriction entitled the optional special authorizat...

The objective of this study was to compare quinolone resistance and gyrA mutations in clinical isolates of Klebsiella pneumoniae and Escherichia coli from Chinese adults who used quinolone in the preceding month and children without any known history of quinolone administration. The antimicrobial susceptibilities of 61 isolates from children and 79 isolates from adults were determined. The muta...

Mycobacterium tuberculosis DNA gyrase, an indispensable nanomachine involved in the regulation of DNA topology, is the only type II topoisomerase present in this organism and is hence the sole target for quinolone action, a crucial drug active against multidrug-resistant tuberculosis. To understand at an atomic level the quinolone resistance mechanism, which emerges in extensively drug resistan...

OBJECTIVES AND METHODS The new fluoroquinolones WCK 771, WCK 1152 and WCK 1153 were developed to overcome quinolone resistance in Gram-positive bacteria. The activity of these new quinolones was tested against 159 clinical isolates of Streptococcus pneumoniae and 52 clinical isolates of Streptococcus pyogenes using the microbroth dilution method. RESULTS MIC50/MIC90 values (mg/L) of WCK 771, ...

Bacteria synchronize group behaviors using quorum sensing, which is advantageous during an infection to thwart immune cell attack and resist deleterious changes in the environment. In Pseudomonas aeruginosa, the Pseudomonas quinolone signal (Pqs) quorum-sensing system is an important component of an interconnected intercellular communication network. Two alkylquinolones, 2-heptyl-4-quinolone (H...

Fluoroquinolones form drug-topoisomerase-DNA complexes that rapidly block transcription and replication. Crystallographic and biochemical studies show that quinolone binding involves a water/metal-ion bridge between the quinolone C3-C4 keto-acid and amino acids in helix-4 of the target proteins, GyrA (gyrase) and ParC (topoisomerase IV). A recent cross-linking study revealed a second drug-bindi...

BACKGROUND Quinolone resistance in Enterobacteriaceae species has increased over the past few years, and is significantly associated to beta-lactam resistance. The aim of this study was to evaluate the prevalence of chromosomal- and plasmid-mediated quinolone resistance in acquired AmpC β-lactamase and/or carbapenemase-producing Enterobacteriaceae isolates. METHODS The presence of chromosomal...