background :    klebsiella pneumoniae is among the most common and significant agents of community and hospital-acquired infections. plasmid mediated quinolone resistance (pmqr) was increasingly identified in enterobacteriaceae family worldwide. plasmid-mediated quinolone resistance (pmqr) was first reported in 1998 from a klebsiella pneumoniae isolate in the usa. till date, five qnr proteins h...

The amount of sparfloxacin uptake was higher than that of norfloxacin uptake in Staphylococcus aureus. Moreover, energy-dependent reduction in quinolone uptake, probably due to active efflux of the quinolone, was observed. The reduction in quinolone uptake appeared to be associated with quinolone resistance in S. aureus.

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...

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...

BACKGROUND The categories of recognized transferable quinolone resistance determinants have been increasing sharply. The rapid horizontal transfer of these quinolone resistance genes has caused concern since they bring new dissemination possibilities for quinolone resistance. METHODS In total, 579 clinical Escherichia coli isolates were subjected to antimicrobial susceptibility testing, scree...

DNA gyrase is a prokaryotic type II topoisomerase and a major target of quinolone antibacterials. The majority of mutations conferring resistance to quinolones arise within the quinolone resistance-determining region of GyrA close to the active site (Tyr(122)) where DNA is bound and cleaved. However, some quinolone resistance mutations are known to exist in GyrB. Present structural data suggest...

We examined the potential for the development of fluoroquinolone resistance in Neisseria meningitidis by cultivating two clinical isolates of meningococci in the presence of concentrations of ciprofloxacin at and about the predetermined MIC. The quinolone resistance determining regions (QRDRs) of gyrA and parC of 50 stable quinolone-resistant mutants derived in vitro were sequenced and compared...

In vitro activity of ozenoxacin, a novel nonfluorinated topical (L. D. Saravolatz and J. Leggett, Clin. Infect. Dis. 37:1210-1215, 2003) quinolone, was compared with the activities of other quinolones against well-characterized quinolone-susceptible and quinolone-resistant Gram-positive bacteria. Ozenoxacin was 3-fold to 321-fold more active than other quinolones. Ozenoxacin could represent a f...

We integrated data on quinolone and macrolide susceptibility patterns with epidemiologic and typing data from Campylobacter jejuni and C. coli infections in two Danish counties. The mean duration of illness was longer for 86 patients with quinolone-resistant C. jejuni infections (median 13.2 days) than for 381 patients with quinolone-sensitive C. jejuni infections (median 10.3 days, p = 0.001)....

The methanol extract from the leaves of Spathelia excelsa yielded six alkaloids: 2-(12-oxo-tridecanyl)-3-methoxy-4-quinolone, 2-(10-hydroxy-10-methyldodecanyl)-3-methoxy-4-quinolone, 2-(11-hydroxy-11-methyldodecanyl)-3-methoxy-4-quinolone, 2-(12-hydroxytridecanyl)-3-methoxy-4-quinolone, 7-hydroxy-2-(3-hydroxy-3-methylbutyl)-4-quinolone and 6-hydroxy-2-(3-hydroxy-3-methylbutyl)-4-quinolone, in a...