The sequence of the DNA gyrase gyrA gene of Serratia marcescens ATCC 14756 was determined. An open reading frame of 2,640 nucleotides coding for a polypeptide with a calculated molecular mass of 97,460 was found, and its sequence complemented the sequence of an Escherichia coli gyrA temperature-sensitive mutation. Analysis of the PCR products of the quinolone resistance-determining regions of g...

Eight hundred and eighty-three strains of Campylobacter spp. isolated between 1982 and 1989 from human stools and poultry products were screened for quinolone resistance. In this period the prevalence of resistant strains isolated from poultry products increased from 0% to 14%. During the same period the prevalence in man increased from 0% to 11%. The emergence of quinolone resistance has impli...

BACKGROUND Quinolone-resistant Neisseria gonorrhoeae has swiftly emerged in Canada. We sought to determine its prevalence in the province of Ontario and to investigate risk factors for quinolone-resistant N. gonorrhoeae infection in a Canadian setting. METHODS We used records from the Public Health Laboratory of the Ontario Agency for Health Protection and Promotion in Toronto, Ontario, and t...

In gram-negative bacteria, gyrase and topoisomerase IV are primary and secondary targets, respectively, of the fluoroquinolones. In addition to the mutations in the genes encoding the target enzymes (1, 4), quinolone resistance may also be associated with increased efflux of the drugs (2, 5). Possible mechanisms of quinolone resistance were investigated in clinical isolates of Shigella dysenter...

BACKGROUND Quinolone resistance in Enterobacteriaceae results mainly from mutations in type II DNA topoisomerase genes and/or changes in the expression of outer membrane and efflux pumps. Several recent studies have indicated that plasmid-mediated resistance mechanisms also play a significant role in fluoroquinolone resistance, and its prevalence is increasing worldwide. In China, the presence ...

We analyzed an outbreak of Escherichia coli bacteremia in eight patients with leukemia in a hematology-oncology unit from July to September 1994. The antibiograms and genotypic patterns of the isolates were different, thus suggesting that the outbreak did not originate from a single clone. However, all the isolates were resistant to quinolones, which led us to examine the microbiological record...

Antimicrobials are heavily used in Chilean salmon aquaculture. We previously found significant differences in antimicrobial-resistant bacteria between sediments from an aquaculture and a non-aquaculture site. We now show that levels of antimicrobial resistance genes (ARG) are significantly higher in antimicrobial-selected marine bacteria than in unselected bacteria from these sites. While ARG i...

Objectives: Quinolone resistance in Escherichia coli occurs mainly as a result of mutations the quinolone-resistance-determining regions gyrA and parC, which encode drugs’ primary targets. Mutational alterations affecting drug permeability or efflux well plasmid-based mechanisms can also contribute to resistance, albeit lesser extent. Simplifying generalizing complex evolutionary trajectories, ...

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...