ICU Admission Screening for Multidrug-Resistant Organism Colonization and Subsequent Infection Risk: A Pilot Study.

Background

MDRO colonization at ICU admission may identify patients at increased risk for hospital-acquired infection (HAI), but its independent predictive value remains incompletely defined.

Methods

We conducted a retrospective observational study of 560 consecutive ICU admissions (July-October 2024). Admission screening assessed colonization with extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales, carbapenem-resistant Enterobacterales (CRE), and vancomycin-resistant enterococci (VRE). The primary outcome was microbiologically confirmed HAI; the secondary outcome was in-hospital mortality. Associations were evaluated using multivariable logistic regression, ROC/AUC analysis, mediation analysis, and a sensitivity analysis restricted to first admissions.

Results

Of 560 admissions, 223 were screen-positive and 283 screen-negative. HAI occurred in 49 patients (8.8%). Positive screening was associated with increased HAI odds, narrowly missing significance in the primary adjusted analysis (OR 1.81, 95% CI 0.96-3.41, p = 0.065) but reaching significance in the first-admission sensitivity analysis (OR 2.09, p = 0.034). CRE showed the strongest adjusted association with HAI (OR 2.33, 95% CI 1.21-4.51, p = 0.012). Screening alone showed poor discrimination (AUC 0.574); combined with clinical variables, discrimination improved substantially (AUC 0.788).

Conclusions

MDRO admission screening was associated with increased HAI odds, particularly for CRE, though screening alone has limited predictive performance. Larger prospective studies are needed to confirm these findings.