Bloodstream infection with extended-spectrum beta-lactamase-producing Enterobacteriaceae at a tertiary care hospital in New Zealand: Risk factors and outcomes

Objectives: To define local risk factors and outcomes for bacteremia with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) at a tertiary hospital in New Zealand. Methods: Patients with ESBL-E bacteremia were compared to matched control patients with non-ESBL-producing Enterobacteriaceae bacteremia. Patients were matched by onset of bacteremia (community vs. hospital), site of blood culture collection (peripheral vs. via central line), and infecting organism species. Results: Forty-four cases with matched controls were included. Eight- and 30-day mortality was higher in cases than controls (27% vs. 7%; p= 0.011 and 34% vs. 11%, p= 0.011). Twenty-one cases (48%) were community-onset. Community-onset cases were associated with urinary tract infection, whereas hospital-onset cases were associated with central line infection, intensive care admission, and Enterobacter cloacae. Independent risk factors for ESBL-E bacteremia were fluoroquinolone exposure (odds ratio (OR) 6.56, 95% confidence interval (CI) 1.79-24), first-generation cephalosporin exposure (OR 12.3, 95% CI 1.01-148), and previously-known colonization with ESBL-E (OR 46.2, 95% CI 3.45-619). Conclusions: The association with fluoroquinolone exposure suggests that measures to reduce unnecessary use may be an effective preventative strategy. Known colonization with ESBL-E is a strong risk factor for ESBL-E bacteremia, and colonization status should be taken into consideration when choosing empirical therapy.