Transmission of MRSA, ESBL , and within a tertiary care hospital and across surrounding facilities in Japan: a molecular epidemiological study with the PCR-based Open-reading frame typing.

Objective: To determine the regional impact of transmission of multidrug-resistant organisms (MRDOs) and () among a tertiary care hospital and surrounding facilities including long-term care facilities (LTCFs).

Design: Retrospective cohort study.

Methods: Patients admitted to a tertiary care hospital from July 2019 to July 2021 were recruited if their clinically collected cultures grew the following pathogens: Methicillin-resistant (MRSA), Extended-Spectrum Beta-Lactamase (ESBL) producing Enterobacterales, with difficult-to-treat resistance, Carbapenem-resistant Enterobaterales, Vancomycin-resistant Enterococci, and . Patient characteristics including admission and discharge pathway were collected. For the isolates of MRSA, ESBL-producing (), and , a molecular epidemiological analysis was conducted, utilizing the PCR-based Open-Reading Frame Typing (POT) method.

Results: Three hundred-five patients were identified with a total of 332 culture specimens of the target pathogens. The top three were 132 MRSA isolates (43.3%, out of 305), 97 ESBL (31.8%), and 32 ESBL Enterobacterales (non-) (10.5%). The target pathogens were more detectable within 3 days among patients admitted from LTCFs or other hospitals than those admitted from home (Odds Ratio 4.6, 95% confidence interval 2.8-7.6, p-value < 0.001). The molecular epidemiological analysis suggested the transmissions of MRSA, ESBL and occurred 52 out of 111 patients within the in-hospital environment, and 7 out of 128 within the prehospital environment, respectively.

Conclusions: MDROs/ transmission is prevalent within a tertiary care hospital and further complicated by its inter-facility transmission across surrounding LTCFs and hospitals in Japan.