Success rates of meticillin-resistant Staphylococcus aureus (MRSA) decolonization and factors associated with failure...

Meticillin-resistant Staphylococcus aureus (MRSA) decolonization is used widely, and various success rates and risk factors for failure have been reported. The aims of this study were to evaluate the success rate of MRSA decolonization and to identify risk factors for failure.

Patients with MRSA colonization from 2007 to 2023 were registered prospectively, and anthropometric information, and data on comorbidities and colonization (e.g. circumstances of detection, number of colonized sites, date of decolonization) were collected, as well as the results of control swabs. The success rate of decolonization (i.e. two or more negative sets of swabs with minimal follow-up of 3 months) was assessed, and multi-variable regression was used to assess the risk factors for failure.

In total, 1170 patients with MRSA were included in this study. Of these, 478 (41%) patients were decolonized within 728 cycles, with a success rate of 28%. On multi-variable analysis, male sex [adjusted odds ratio (aOR) 2.2, 95% confidence interval (CI) 1.4-3.4; P<0.01], older age (aOR 1.1 per 10 years, 95% CI 1.0-1.2), number of previous decolonizations (aOR 2.1 per cycle, 95% CI 1.2-3.5; P<0.01), and number of positive sites (aOR 1.5 per site, 95% CI 1.2-1.9, P<0.01) were risk factors for failure. Use of systemic antibiotics (aOR 1.6, 95% CI 0.8-3.3; P=0.2) was not associated with the outcome.

Over the 16-year period, 28% of patients were decolonized successfully. Male sex was identified as a novel risk factor for failure. The failure rate increased with every additional decolonization cycle, irrespective of the use of systemic antibiotics. These findings can inform patients and caregivers about the expected success rate based on individual risk profiles.