The role of Sequence Type (ST) 131 in adult community-onset non-ESBL-producing Escherichia coli bacteraemia

Background: To compare the epidemiological and clinical features and outcome in clonal group O25b/ST131 and non-clonal group O25b/ST131 in adult patients with non-extended-spectrum B-lactamase (ESBL)-producing Escherichia coli (E. coli) bacteraemia. Methods: We collected 371 consecutive isolates with community-onset non-ESBL producing E. coli bloodstream infection in 2010 in a 1200-bed hospital in Taiwan. Twenty adult patients with clonal group O25b/ST131 and 40 patients with non-clonal group O25b/ST131 were compared. Result: Clonal group O25b/ST131 accounted for 5.9% of total isolates. The underlying disease and healthcare-associated risk factors were similar in the case and control groups. Patients with the clonal group O25b/ST131 were less likely to have intra-abdominal infection (0% vs. 22.5%; p < 0.05) than patients from the control group. The Day 30 mortality rate was similar in the case and control groups (15% vs. 12.5%). Conclusions: Clonal group O25b/ST131 was found in both multidrug-resistant and susceptible E. coli strains, causing community-onset bloodstream infection. Although O25b/ST131 does not lead to a higher mortality than other isolates, choosing an appropriate antimicrobials in the empirical therapy of community-onset E. coli bacteraemia has become more challenging.