Risk factors and outcomes of infections caused by extremely drug-resistant gram-negative bacilli in patients hospitalized in intensive care units

Background: Extremely drug-resistant gram-negative bacilli (XDR-GNB) increasingly cause health care-associated infections (HAIs) in intensive care units (ICUs). Methods: A matched case-control (1:2) study was conducted from February 2007 to January 2010 in 16 ICUs. Case and control subjects had HAIs caused by GNB susceptible to <= 1 antibiotic versus >= 2 antibiotics, respectively. Logistic and Cox proportional hazards regression assessed risk factors for HAIs and predictors of mortality, respectively. Results: Overall, 103 case and 195 control subjects were enrolled. An immunocompromised state (odds ratio [OR], 1.55; P -.047) and exposure to amikacin (OR, 13.81; P <.001), levofloxacin (OR, 2.05; P -.005), or trimethoprim-sulfamethoxazole (OR, 3.42; P =.009) were factors associated with XDR-GNB HAIs. Multiple factors in both case and control subjects significantly predicted increased mortality at different time intervals after HAI diagnosis. At 7 days, liver disease (hazard ratio [HR], 5.52), immunocompromised state (HR, 3.41), and bloodstream infection (HR, 2.55) predicted mortality; at 15 days, age (HR, 1.02 per year increase), liver disease (HR, 3.34), and immunocompromised state (HR, 2.03) predicted mortality; and, at 30 days, age (HR, 1.02 per 1-year increase), liver disease (HR, 3.34), immunocompromised state (HR, 2.03), and hospitalization in a medical ICU (HR, 1.85) predicted mortality. Conclusion: HAIs caused by XDR-GNB were associated with potentially modifiable factors. Age, liver disease, and immunocompromised state, but not XDR-GNB HAIs, were associated with mortality. Copyright (C) 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.