Prevalence, acquisition, and risk factors of carbapenem-resistant enterobacterales colonization in long-term care hospitals: A prospective active surveillance study

Background Carbapenem-resistant Enterobacterales (CRE) represent a critical threat to patient safety, particularly in long-term care hospitals (LTCHs) where elderly patients with multiple comorbidities are concentrated. Objective To analyze asymptomatic CRE colonization, acquisition and risk factors in LTCHs prospectively. Methods A prospective active surveillance study was conducted on 140 patients across four LTCHs in Korea from November 2023 to December 2024. Rectal swab cultures were performed weekly for up to six weeks and at three months to isolate CRE. Prevalence, acquisition rate, time to detection, and risk factors for CRE colonization were analyzed. Kaplan–Meier curves were used to compare acquisition patterns according to patient type, and Cox proportional-hazard models were applied to identify risk factors among patients who were CRE-negative at baseline. Results The overall prevalence of asymptomatic CRE colonization was 24.3% (34/140). The colonization rate was higher among newly admitted patients (30.8%) compared to current inpatients (21.8%). Carbapenemase-producing Enterobacterales (CPE) accounted for 80.0% of CRE isolates, with KPC being predominant. Among initially negative patients, 8.6% acquired CRE during hospitalization. Kaplan–Meier analysis revealed a dynamic pattern: current inpatients showed higher acquisition rates early on, while newly admitted patients showed higher cumulative rates after three weeks. Key risk factors included invasive device use within the past year (hazard ratio, HR: 9.83) and prior room sharing with CRE patients (HR: 5.01). Conclusions LTCHs serve as favorable environments for both CRE importation and intra-facility transmission. Strict adherence to standard precautions, targeted screening of high-risk individuals, and prompt cohorting or isolation of CRE-positive patients are essential for effective control. These findings provide prospective evidence supporting strengthened surveillance and infection prevention strategies in long-term care settings.