DW-224a is a new broad-spectrum quinolone with excellent antipneumococcal activity. Agar dilution MIC was used to test the activity of DW-224a compared to those of penicillin, ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin, gemifloxacin, amoxicillin-clavulanate, cefuroxime, and azithromycin against 353 quinolone-susceptible pneumococci. The MICs of 29 quinolone-resistant pneumococci wi...

Since quinolones are synthetic antibiotics, it was predicted that mutations in target genes would be the only mechanism through which resistance could be acquired, because there will not be quinolone-resistance genes in nature. Contrary to this prediction, a variety of elements ranging from efflux pumps, target-protecting proteins, and even quinolone-modifying enzymes have been shown to contrib...

Physiologic and environmental factors can modulate antibiotic activity and thus pose a significant challenge to antibiotic treatment. The quinolone class of antibiotics, which targets bacterial topoisomerases, fails to kill bacteria that have grown to high density; however, the mechanistic basis for this persistence is unclear. Here, we show that exhaustion of the metabolic inputs that couple c...

additive effect on quinolone susceptibility.7 Though Qnr proteins and Aac(60)-Ib-cr only induce low level quinolone resistance, they are known to facilitate selection of resistancemutations in the presence of concentrations of quinolone antibiotics.8 We describe an isolate of K. pneumoniae isolate carrying three plasmid-mediated quinolone-resistant genes (qnrB, qnrS and aac (60)-Ib-cr variant) ...

Investigation of the Frequency Plasmid-Dependent Quinolone Resistance Genes in Klebsiella Pneumoniae, Pseudomonas Aeruginosa and Escherichia Coli Isolated from Surgical Site Infections

We have investigated the interaction of quinolones with DNA by a number of methods to establish whether a particular binding mode correlates with quinolone potency. The specificities of the quinolone-mediated DNA cleavage reaction of DNA gyrase were compared for a number of quinolones. Two patterns that depended on the potency of the quinolone were identified. Binding to plasmid DNA was examine...

We determined the prevalence of plasmid-mediated quinolone resistance mechanisms among non-Typhi Salmonella spp. isolated from humans, food animals, and retail meat in the United States in 2007. Six isolates collected from humans harbored aac(6')Ib-cr or a qnr gene. Most prevalent was qnrS1. No animal or retail meat isolates harbored a plasmid-mediated mechanism.

The pharmacokinetics of the quinolone enoxacin were studied after a 600-mg oral dose was given to each of six male volunteers. The levels of the compound were measured in serum, blister fluid, and urine. Absorption was variable, with peak levels (mean, 3.7 micrograms/ml) being attained between 0.75 and 3.0 h (mean, 1.9 h). The serum elimination half-life was 6.2 h, and 71.6% of the drug was rec...

PURPOSE To perform a meta-analysis to estimate the efficacy of quinolone antibiotics in preventing infections, fevers, and deaths among cancer patients neutropenic following chemotherapy. METHODS We searched MEDLINE to identify randomized trials of quinolone prophylaxis, controlled either with no prophylaxis or trimethoprim/sulfamethoxazole (TMS) prophylaxis. We pooled relative risks for outc...

BACKGROUND Antibiotic resistance has necessitated fluoroquinolone use but little is known about the selective forces and resistance trajectory in malaria-endemic settings, where selection from the antimalarial chloroquine for fluoroquinolone-resistant bacteria has been proposed. METHODS Antimicrobial resistance was studied in fecal Escherichia coli isolates in a Nigerian community. Quinolone-...