Extremely drug-resistant gram-negative bacilli (XDR-GNB) increasingly cause healthcare-associated infections (HAIs) in intensive care units (ICUs).
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.
Overall, 103 case and 195 control subjects were enrolled. An immunocompromised state (OR=1.55, p=0.047) and exposure to amikacin (OR=13.81, p<0.001), levofloxacin (OR=2.05, p=0.005), or trimethoprim-sulfamethoxazole (OR=3.42, p=0.009) 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 [HZ]=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 one year increase), liver disease (HR=3.34), immunocompromised state (HR=2.03), and hospitalization in a medical ICU (HR=1.85) predicted mortality.
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.