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Virulence Factors of Escherichia coli Isolates That Produce CTX-M-Type Extended-Spectrum β-Lactamases

2005; American Society for Microbiology; Volume: 49; Issue: 11 Linguagem: Inglês

10.1128/aac.49.11.4667-4670.2005

1098-6596

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

Urinary Tract Infections Management

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 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.