Clinical and Molecular Correlates of Escherichia coli Bloodstream Infection from Two Geographically Diverse Centers in Rochester, Minnesota, and Singapore.

bacteremia is caused mainly by sequence type complex 131 (STc131) and two clades within its fluoroquinolone-resistance-associated 30 subclone, 30R1 and 30Rx. We examined clinical and molecular correlates of bacteremia in two geographically distinct centers. We retrospectively studied 251 unique bloodstream isolates from 246 patients (48 from the Mayo Clinic, Rochester, MN [MN], and 198 from Tan Tock Seng Hospital, Singapore [SG]), from October 2013 through March 2014. Isolates underwent PCR for phylogroup, STc, type, and virulence gene profiles, and medical records were reviewed. Although STc131 accounted for 25 to 27% of all bacteremia isolates at each site, its extended-spectrum-β-lactamase (ESBL)-associated 30Rx clade was more prominent in SG than in MN (15% versus 4%; = 0.04). In SG only, patients with STc131 (versus other STc isolates) were more likely to receive inactive initial antibiotics (odds ratio, 2.8; = 0.005); this was true specifically for patients with 30Rx (odds ratio, 7.0; = 0.005). 30Rx comprised 16% of community-onset bacteremia episodes in SG but none in MN. In SG, virulence scores were higher for 30Rx than for 30R1, non-30 STc131, and non-STc131 isolates ( < 0.02 for all comparisons). At neither site did mortality differ by clonal status. The ESBL-associated 30Rx clade was more prevalent and more often of community onset in SG, where it predicted inactive empirical treatment. The clonal distribution varies geographically and has potentially important clinical implications. Rapid susceptibility testing and clonal diagnostics for 30/30Rx might facilitate earlier prescribing of active therapy.