Clonal distribution and associated characteristics of Escherichia coli clinical and surveillance isolates from a military medical center

•Among 100 ESBL or non-ESBL E. coli isolates from a US military medical center:•Clonal types, resistance, and virulence genes mirrored those in other US studies.•ST131-H30, ST10, and ST648 were the most common clonal lineages.•ST131-H30 was associated with a clinical origin, regardless of ESBL status.

Antimicrobial-resistant Escherichia coli are a concern for military health services. We studied 100 extended-spectrum beta-lactamase (ESBL)-producing and non-producing E. coli clinical and surveillance isolates from military personnel and civilians at Brooke Army Medical Center (2007-2011). Major E. coli lineages, most prominently ST10 (24%), ST131 (16%), and ST648 (8%), were distributed much as reported for other North American populations. ST131, represented mainly by its resistance-associated ST131-H30 clonal subset, was uniquely associated with a clinical origin, regardless of ESBL status. Thus, clonal background predicted resistance phenotype and clinical versus surveillance origin, and these findings could assist military clinicians and epidemiologists.