ESBL-colonization at ICU admission: impact on subsequent infection, carbapenem-consumption, and outcome

Objective: To determine whether colonization with extended-spectrum P-lactamase-producing Enterobacteriaceae (ESBL-PE) predicts the risk for subsequent infection and impacts carbapenem-consumption and outcome in intensive care unit (ICU) patients. Design: Prospective cohort study. Setting: The 2 ICUs in the University Hospital Basel in Switzerland. Patients: All patients admitted to the 2 ICUs providing mechanical ventilation and an expected ICU stay >48 hours. Methods: Patients were routinely screened for ESBL-PE carriage by rectal swab on admission. Competing risk regression analyses were applied to calculate hazard ratios (HRs) for infection with ESBL-PE and mortality. Length of hospital stay, length of ICU stay, and duration of carbapenem exposure were compared using the Mann-Whitney U test. Results: Among 302 patients, 24 (8.0%) were colonized with ESBL-PE on ICU admission. Infections with ESBL-PE occurred in 4 patients, of whom 3 (75%) were identified as ESBL-PE colonized on admission. ESBL-PE colonization on admission was associated with subsequent ESBL-PE infection (hazard ratio [HR], 25.52; 95% confidence interval [CI], 2.40-271.41; P = .007) and exposure to carbapenems (HR, 2.42; 95% CI, 1.01-5.79; P = .047), whereas duration of carbapenem exposure did not differ in relation to ESBL-PE colonization (median, 7 days [IQR, 3-8 days] vs median, 6 days [IQR 3-9 days]; P = 0.983). Patients colonized with ESBL-PE were not at increased risk for death overall (HR, 1.00; 95% CI, 0.44-2.30; P = .993) or death attributable to infection (HR, 1.20; 95% CI, 0.28-5.11; P = .808). Conclusions: Screening strategies for detection of ESBL-PE colonization on ICU admission may allow the identification of patients at highest risk for ESBL-PE infection and the correct allocation of empiric carbapenem treatment.