Fluoroquinolone-resistant uropathogenic Escherichia coli in Norway: evidence of clonal spread.

Prevalence, resistance profiles, virulence gene complements, and phylogenetic and clonal affinities of fluoroquinolone-resistant Escherichia coli from urinary tract infections (UTIs) in Norway were investigated. Of 7302 E. coli UTI isolates from 2003, 1.2% were fluoroquinolone-resistant; 35 of these fluoroquinolone-resistant isolates were included in the present study. The isolates were predominantly multiresistant, carried few virulence factors, and tended to belong to the less-virulent phylogroups A and B1. Although the isolates were genetically heterogeneous, there was evidence of a limited degree of clonal dissemination.