title: Virulence factors of Escherichia coli isolates that produce CTX-M-type extended-spectrum beta-lactamases.
abstract: This study determined the phylogenetic groups and virulence factors of 37 Escherichia coli isolates producing types of CTX-M compared with those of 19 isolates producing different types of extended-spectrum beta-lactamases (ESBLs) in a well-defined North American population. Most CTX-M-14 producers (97%) were from phylogenic group D; 67% of the CTX-M-15 producers were from group B2. A single CTX-M-14-producing strain belonged to clonal group A. There were significant prevalence differences for individual virulence factors among CTX-M producers and nonproducers; however, aggregate virulence factor scores were similar. CTX-M producers more commonly caused repeat urinary tract infections. Our results indicate that CTX-M type predicts phylogenetic background, and the virulence potential of ESBL-producing E. coli isolates is a complex issue, requiring further study and ongoing surveillance.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Calgary, Alberta, Canada. johann.pitout@cls.ab.ca
authors.forename: Johann D D
authors.initials: JD
authors.lastname: Pitout
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Laupland
authors.forename: Deirdre L
authors.initials: DL
authors.lastname: Church
authors.forename: Megan L
authors.initials: ML
authors.lastname: Menard
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
mesh_terms: D004926:Escherichia coli / Q000145:classification / Q000201:enzymology / Q000472:pathogenicity*; D006801:Humans; D010802:Phylogeny; D037521:Virulence Factors / Q000032:analysis*; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D037521:Virulence Factors; C456080:beta-lactamase CTX-M-14; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases