Risk factors and outcomes of carbapenem-nonsusceptible Escherichia coli bacteremia: A matched case-control study

Background: Infections due to carbapenem-resistant Enterobacteriaceae have been the emerging problem worldwide. This primary object of this study was to understand the risk factors and clinical outcomes of carbapenem-nonsusceptible Escherichia coli (CNSEc) bacteremia. Methods: We conducted a matched case control study in a 3,715-bed tertiary care medical center in northern Taiwan. The controls were selected among patients with carbapenemsusceptible E coli and were matched with CNSEc for bacteremia. Results: Fifty-one patients were included in this study (17 cases and 34 controls). Bivariate analysis showed that prior exposure to carbapenems (p < 0.001), stay in intensive care units (p = 0.016), placement of central venous catheters (p = 0.001), chronic liver diseases (p < 0.001), uremia with regular dialysis (p = 0.004), and mechanical ventilation (p = 0.004) were associated with CNSEc bacteremia. Multivariate analysis revealed that prior exposure to carbapenems [odds ratio (OR), 29.17; 95% confidence interval (Cl), 1.76-484.70; p = 0.019], uremia with regular dialysis (OR, 98.58; 95% Cl, 4.02-999; p = 0.005) and chronic liver diseases (OR, 27.86; 95% Cl, 2.31-335.83; p = 0.009) were independent risk factors for CNSEc bacteremia. Compared with carbapenem-susceptible E coli group, CNSEc group had a longer hospital stay (68.4 days vs. 35.8 days; p = 0.04) and a higher disease severity, as indicated by a Pittsburgh bacteremia score greater than or equal to 4 (5.6% vs. 2.5%; p = 0.015). Patients with CNSEc bacteremia had a higher overall in-hospital mortality rate (94.12% vs. 50.00%; p = 0.002), but there was no difference in the 28-day mortality between these two groups. Conclusions: CNSEc bacteremia would lead to a poor outcome among patients with prior exposure to carbapenems, chronic liver disease, and uremia with regular dialysis. Copyright (C) 2011, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC. All rights reserved.