Detection of CTX-M-27 β-Lactamase Genes on Two Distinct Plasmid Types in ST38 Escherichia coli from Three U.S. States.

Infections caused by extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli are a significant cause of morbidity and health care costs. Globally, the prevailing clonal type is ST131 in association with the bla _CTX-M-15 β-lactamase gene. However, other ESBLs, such as bla _CTX-M-14 and bla _CTX-M-27 , can also be prevalent in some regions. We identified ST38 ESBL-producing E. coli from different regions in the United States which carry bla _CTX-M-27 embedded on two distinct plasmid types, suggesting the potential emergence of new ESBL lineages.