Targeted MRSA decolonisation reduces the risk of subsequent MRSA infection - a quasi-experimental study.

INTRODUCTION: We investigated the effect of a hospital-wide targeted MRSA decolonisation program on the risk of subsequent MRSA infection and/or bacteraemia. METHODS: This is a before-and-after comparison study that took place in a university-affiliated hospital in Hong Kong. In-patient MRSA decolonisation with nasal mupirocin and chlorhexidine shower or washcloths was introduced to all adult patients with MRSA from 27 August 2024. Patients with MRSA with decolonisation in the period from 27 August 2024 to 20 August 2025 were designated as the intervention group. Patients with MRSA without decolonisation in the period from 4 August 2023 to 10 August 2024 were designated as the control group. All patients were followed up until 20 November 2025. Two outcomes were examined: 1. the time to the next MRSA in any clinical specimen, and 2. the time to the next MRSA in blood culture. Multivariable Cox proportional hazard regression was used to analyze the effect of intervention on the time to the first positive MRSA infection and the time to the next MRSA bacteraemia. RESULTS: There were 932 patients in intervention group and 996 in control group. The median age of was 79 years, and M:F ratio was 1.56:1. The intervention group was associated with a lower risk of subsequent MRSA infection (aHR = 0.77, p = 0.015). A trend towards reduction in subsequent MRSA bacteraemia was detected in the intervention group (aHR = 0.52, p = 0.054). CONCLUSIONS: Hospital-wide targeted MRSA decolonisation was associated with a lower risk of subsequent MRSA infection.