Successful control of methicillin-resistant Staphylococcus aureus in a spinal cord injury center : a 10-year prospective study including molecular typing

STUDY DESIGN: Prospective cohort study with medical record review. OBJECTIVE: To evaluate the clinical utility of an infection control program in a patient cohort at high risk for methicillin-resistant Staphylococcus aureus (MRSA) infection and to identify risk factors interfering with successful decolonization of MRSA. SETTING: All spinal cord injured (SCI) patients hospitalized at the Swiss Paraplegic Center (SPC) Nottwil from April 1991 to April 2001. METHODS: Patients whose medical records indicated laboratory-confirmed MRSA colonization or infection were included. Incidence of MRSA colonization or infection was classified as community acquired, nosocomial or transferred based on standardized criteria. Risk factors for community-acquired MRSA colonization in SCI patients were determined. MRSA subtyping and identification of nosocomial spread was performed through pulse-field gel electrophoresis (PFGE). RESULTS: Of 5992 admissions, 100 episodes of MRSA (colonization 22 cases, infection 78 cases) were identified among 76 patients. Overall incidence (1991-2001) per 1000 patient days was 0.26 cases on admission compared to 0.08 at discharge (P>0.001). Community-acquired MRSA was most frequent (56%) followed by nosocomial acquisition (34%). PFGE subtyping identified two nosocomial clusters with six and three cases, respectively. Most of community-acquired MRSA isolates were genetically unrelated and also distinct from epidemic strains identified in Switzerland during the study period. Decolonization was successful in 60 of 76 (78.9%) MRSA-positive patients. CONCLUSION: In the largest European SCI center, MRSA controlling is feasible if infection control policies are vigorously applied.