Twelve clinical isolates of Ureaplasma spp. and one isolate of Mycoplasma hominis were examined for resistance to fluoroquinolones. Previously described mutations at positions 83 and 95 in GyrA (Escherichia coli numbering) and positions 80 and 87 in ParC were found. Unusual alterations were described at positions ParC 123 and 134.

The in vitro activities of ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin against a large collection of clinical isolates of Streptococcus pneumoniae (n = 4,650) obtained over a 5-year period, 1994-1995 through 1999-2000, were assessed as part of a longitudinal multicenter U.S. surveillance study of antimicrobial resistance. Three sampling periods were used during this investigatio...

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...

OBJECTIVES To investigate the mechanism of ciprofloxacin resistance in isolates of Acinetobacter baumannii during two hospital outbreaks and to determine the expression level of the gene encoding the AdeB efflux pump. METHODS Isolates were previously typed by PFGE and their MICs determined by broth microdilution. The gyrA and parC genes were sequenced and the adeB gene examined by real-time r...

In this study, we investigated the presence of plasmid-mediated quinolone resistance (PMQR) genes among 101 ciprofloxacin-resistant urinary Escherichia coli isolates and searched for mutations in the quinolone-resistance-determining regions (QRDRs) of the DNA gyrase and topoisomerase IV genes in PMQR-carrying isolates. Eight isolates harboured the qnr and aac(6')-Ib-cr genes (3 qnrS1, 1 qnrB19 ...

Resistance to fluoroquinolones (FQ) is being increasingly reported and found to be mediated by efflux pumps, plasmid-mediated quinolone resistance genes (PMQR) and mutations in gyrA, gyrB, parC and parE. However, studies reporting on FQ resistance mechanisms (FQRM), particularly in Africa, are focused mostly on Salmonella. This study used a whole-genome-based approach to describe FQRM in forty-...

OBJECTIVES To define the genetic characteristics and resistance mechanisms of clinical isolates of Salmonella enterica serovar Typhi (S. Typhi) and S. enterica serovar Paratyphi A (S. Paratyphi A) exhibiting high-level fluoroquinolones resistance. METHODS Three S. Typhi and two S. Paratyphi A ciprofloxacin-resistant isolates (MICs > 4 mg/L) were compared with isolates with reduced susceptibil...

The increased Salmonella resistance to quinolones and fluoroquinolones is a public health concern in the Southeast Asian region. The objective of this study is to develop a high resolution melt curve (HRM) assay to rapidly screen for mutations in quinolone-resistant determining region (QRDR) of gyrase and topoisomerase IV genes. DNA sequencing was performed on 62 Salmonella strains to identify ...

OBJECTIVES Fluoroquinolone-resistant Streptococcus pneumoniae are increasing worldwide rapidly. In vitro activities of sitafloxacin were evaluated against clinical isolates of S. pneumoniae resistant to levofloxacin (MIC of levofloxacin > or = 4 mg/L), which were characterized genetically. METHODS The quinolone resistance determining regions (QRDRs) of gyrA, gyrB, parC and parE of these strai...

OBJECTIVES The aim of this study was to characterize fluoroquinolone-resistant Shigella and determine whether the qnr and aac(6')-Ib-cr genes could contribute to sporadic shigellosis at the clinic in the Hangzhou area of China. METHODS A total of 202 strains of Shigella (79 Shigella sonnei and 123 Shigella flexneri ) isolated from sporadic cases of shigellosis from 1998 to 2007 were analysed ...