Within-host diversity of ESBL-producing Escherichia coli. Escherichia coli

Extended-spectrum beta-lactamase(ESBL)-producing Escherichia coli are of increasing clinical concern globally. ESBL-producing clones causing infection can also be carried asymptomatically in the gastrointestinal tract of human hosts, however surveillance efforts investigating carriage strains typically focus on molecular typing of single colonies obtained from selective culture. The diversity of non-ESBL E. coli strains in carriage has been shown to be substantial, and this may be applicable to drug-resistant isolates as well, with important implications for transmission studies. This study used a high-resolution typing method (whole genome sequencing), to investigate the diversity of ESBL-producing E. coli carried in the gastrointestinal tract of individuals in a region with a high ESBL prevalence.