Virulence factors of Escherichia coli isolates that produce CTX-M-type extended-spectrum β-lactamases

Johann D.D. Pitout, Kevin B. Laupland, Deirdre L. Church, Megan L. Menard, James R. Johnson

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


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 β-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.

Original languageEnglish (US)
Pages (from-to)4667-4670
Number of pages4
JournalAntimicrobial agents and chemotherapy
Issue number11
StatePublished - Nov 2005


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