A total of 514 consecutive clinical Escherichia coli isolates, irrespective of resistance background, were collected in the period 2002-2008 in Wenzhou, southern China, to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR). The dominant PMQR gene was aac(6')-Ib-cr, followed by qnr, whereas qepA was absent. A total of 253 (49.2%) of these isolates were aac(6')-Ib-positive...

Fluorochinolones are a class of broad-spectrum antimicrobials in the treatment of several infections, including those caused by Escherichia coli. Due to the increasing resistance of bacteria to antimicrobials, an understanding of fluoroquinolone resistance is important for infection control. The aim of this study was to determine susceptibility of clinical E. coli strains to fluoroquinolones an...

We investigated the prevalence of qnr and aac(6')-Ib-cr genes in water-borne environmental bacteria and in clinical isolates of Enterobacteriaceae, as well as the subtypes of qnr. Environmental bacteria were isolated from surface water samples obtained from 10 different locations in Hangzhou City, and clinical isolates of Citrobacter freundii were isolated from several hospitals in four cities ...

BACKGROUND Plasmid-mediated quinolone resistance is an increasing clinical concern, globally. The major objective of the present study was to identify the qnr-encoding genes among the quinolone non-susceptible K. pneumoniae isolates obtained from two provinces in Iran. METHODS A total of 200 K. pneumoniae isolates were obtained from hospitals of Qazvin and Tehran, Iran. The identification of ...

QnrB1 is a plasmid-encoded pentapeptide repeat protein (PRP) that confers a moderate degree of resistance to fluoroquinolones. Its gene was cloned into an expression vector with an N-terminal polyhistidine tag, and the protein was purified by nickel affinity chromatography. The structure of QnrB1 was determined by a combination of trypsinolysis, surface mutagenesis, and single anomalous dispers...

OBJECTIVES To determine the fluoroquinolone resistance determinants in Salmonella enterica serovar Schwarzengrund from imported foods. METHODS Antibiotic susceptibility of Salmonella Schwarzengrund to 16 antibiotics was examined using disc agar diffusion and Etest. Quinolone resistance determinants were examined by sequence analysis of gyrA, gyrB, parC and parE, PCR amplification of qnrA, qnr...