Genotypic characteristics of multidrug‐resistant E scherichia coli isolates associated with urinary tract infections

E scherichia coli is an important pathogen involved in community‐acquired urinary tract infections ( CA ‐ UTI s). In this study, we analyzed the prevalence of frequently occurring genes and the distribution of integrons in 51 multidrug‐resistant ( MDR ) E . coli isolates associated with CA ‐ UTI s. The clonality of these strains was investigated by phylogrouping, multi‐locus sequence typing, and pulsed‐field gel electrophoresis ( PFGE ). All these strains were found to produce two or more resistance determinants, ceftazidime‐hydrolyzing CTX ‐M‐type extended‐spectrum β‐lactamases ( ESBL s) and plasmid‐mediated quinolone resistance determinants were the most prevalent (92.2% and 51.0%, respectively). A sulfhydryl variable‐61‐producing E . coli strain was identified for the first time in C hina. The prevalence of class 1 integrons was 54.9%, class 2 integrons were detected in three isolates but no isolate contained a class 3 integron. Phylogenetic group D was the dominant, observed in 70.6% of the isolates. PFGE analysis revealed a high level of diversity. Twenty‐four distinctive sequence types ( ST s) including four major ST s ( ST 648, ST 224, ST 38, and ST 405) were identified. To our knowledge, this is the first report on the characterization of MDR E . coli isolates associated with CA ‐ UTI s in C hina; our results suggest that an MDR D‐ ST 648 clone producing CTX ‐M‐ ESBL s has emerged as a major clone in the community setting.