Significance of rectal screening for Carbapenem-resistant Enterobacterales in adult patients in intensive care unit: Colonization risk factors and impact on survival: A retrospective cohort study.

Abstract

Carbapenem-resistant Enterobacterales (CRE) infections are difficult to treat and are associated with high morbidity and mortality. Therefore, it is important to rapidly identify the carriers. This study aimed to investigate the clinical and microbiological risk factors associated with CRE colonization, infection, and mortality rates in adult intensive care unit (ICU) patients. A retrospective cohort analysis was performed in the adult ICU of Selahaddin Eyyubi State Hospital, Diyarbakır, Türkiye, between October 2022 and February 2024. Rectal swabs were obtained at ICU admission and weekly thereafter. Based on clinical, laboratory, and microbiological findings, the patients were categorized into colonized or infected groups. Demographic parameters, comorbidities, device use, previous antibiotic exposure, and mortality were analyzed using logistic regression, Kaplan-Meier survival estimates, and Cox proportional hazard modeling. Of the 420 patients, 69 (16.4%) were CRE-positive, 46 (66.7%) remained colonized, and 23 (33.3%) developed infections. The most frequent isolates were Klebsiella pneumoniae (63.8%) and Escherichia coli (36.2%). Independent risk factors for colonization included male sex, prolonged hospitalization, pulmonary or cerebrovascular disease, and prior exposure to β-lactam/β-lactamase inhibitors or cephalosporin antibiotics. CRE infection was related to prior β-lactam/β-lactamase inhibitor and carbapenem use. Mortality was 65.2% in the colonized-infected group versus 13% in those with colonization alone (P < 0.001). Overall survival was similar for CRE-positive and CRE-negative patients, but infected patients had higher mortality rates than colonized patients. CRE colonization in ICU patients poses a substantial risk once infection develops and is closely associated with broad-spectrum antibiotic exposure. These findings support routine rectal CRE screening as a key tool for identifying high-risk patients and informing antibiotic stewardship strategies aimed at preventing progression to fatal infections and improving survival.