Factors for persistence of MRSA carriage one year after initial detection in individuals from various healthcare institutions

Introduction and objective We studied the natural history of patients with chronic stable illnesses that are colonized by Methicillin Resistant Staphylococcus aureus (MRSA). The aim was to determine the persistence colonization 1 year after. Moreover, we intended to disclose factors that predict MRSA persistence. Material and methods A multicentric, prospective observational study was designed. Patients from an acute-care hospital and 4 long-term healthcare facilities were included. Demographic, clinical and microbiological data (nasal and skin swabs) were obtained every 3 months during a year. MRSA carriers were decolonized with nasal mupirocin. Results Among the 699 screened patients, 114 MRSA carriers were identified. MRSA carriage persisted in 59.4% of those who completed the follow-up. Baseline factors associated to MRSA persistence were heart failure, comorbidities, antibiotics, and ulcers. At one year: LTHF, underweight, Barthel<60, and ulcers (the two latest were independent predictors). Persistence was not associated to decolonization. Conclusion Our study disclosed a high MRSA persistence rate and identified several associated factors (both at baseline and one year later). This information may be useful to identify individuals at high-risk of being MRSA carriers at hospital admission.