Plasmid-carried quinolone resistance genes, like qnrA, are widespread in Enterobacteriaceae. To gain insight into its little-understood native functions, we studied the effect of environmental conditions on chromosomal qnrA expression in Shewanella algae. Among conditions of DNA damage, oxidative and osmotic stress, starvation, heat, and cold, only cold shock increased gene expression, as measu...

OBJECTIVES To determine the prevalence of the plasmid-mediated quinolone resistance qnrA gene in a selected collection of blood culture isolates of Enterobacteriaceae resistant to both ciprofloxacin and cefotaxime. METHODS Over a 29 month period, a total of 47 non-repetitive isolates of Enterobacteriaceae resistant to both ciprofloxacin and cefotaxime were identified. Isolates were screened f...

Although quinolone resistance results mostly from chromosomal mutations in Enterobacteriaceae, it may also be mediated by plasmid-encoded Qnr determinants. Qnr proteins protect DNA from quinolone binding and compromise the efficacy of quinolones such as nalidixic acid. Qnr proteins (QnrA-like, QnrB and QnrS) have been identified worldwide with a quite high prevalence among Asian isolates with a...

The plasmid-encoded quinolone resistance gene qnrA confers low-level quinolone resistance, facilitating selection of higher-level resistance. Epidemiologic surveys for qnrA were extended to isolates of Enterobacter spp. and to quinolone-susceptible Enterobacteriaceae. Two (10%) of 20 ceftazidime-resistant quinolone-susceptible Klebsiella pneumoniae strains carried the gene, as did 12 (17%) of 7...

INTRODUCTION Plasmid-mediated quinolone resistance, which complicates treatment, has been increasingly identified in Escherichia coli isolates worldwide. The purpose of this study was to identify the plasmid-mediated qnrA and qnrB genes among the quinolone-resistant Escherichia coli isolated from urinary tract infections in Iran. METHODOLOGY A total of 140 Escherichia coli isolates were colle...

OBJECTIVES Extensive use of quinolones has been associated with raising level of resistance. In the current, we focused on assessing the prevalence of Escherichia coli resistance to quinolones and frequency of qnrA, qnrB and qnrS in non ESBLs (extended spectrum beta-lactamases) and ESBLs producing E. coli with blaSHV and blaTEM. MATERIALS AND METHODS One hundred and fifty E. coli isolates wer...

OBJECTIVES To investigate the presence of antibiotic resistance genes (ARGs), related to commonly used β-lactams and quinolones, in Escherichia coli present in hospital wastewater in central India. METHODS Cefotaxime- and ciprofloxacin-resistant E. coli isolates from hospital-associated wastewater samples were collected from two tertiary care hospitals in the Ujjain district of India during 2...

Wastewater discharged from clinical isolation and general wards at two hospitals in Singapore was examined to determine the emerging trends of antibiotic resistance (AR). We quantified the concentrations of 12 antibiotic compounds by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS), antibiotic-resistant bacteria (ARB), the class 1 integrase gene (intI1), and 16 antibioti...