Prevalence of Methicillin-resistant Staphylococcus Aureus (MRSA) in a Medical Center and Efficacy of Altabax in Clearing MRSA Nasal Colonization

The purpose of the study is to determine whether Altabax (retapamulin ointment, 1%) is effective in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization. The hypothesis is that the prevalence of MRSA increases as a function of increasing clinical exposure and that the topical antibiotic Altabax is efficacious in clearing MRSA nasal colonization. The prevalence of MRSA nasal colonization among Tulane University medical students and residents and physicians of Tulane Medical Center and Ochsner Medical Center will be investigated. A total of 300 subjects will be recruited for the study. After giving informed consent, subjects will be swabbed to obtain specimens for culture and asked to complete a short survey to assess risk factors. Swabs will be used to directly inoculate three types of plates: CHROMagar MRSA plates, Spectra MRSA plates, and TSA with sheep blood plates. After appropriate incubation, Staph latex slide tests will be done and then results confirmed with cefoxitin disk susceptibility testing. MRSA positive subjects will be offered a treatment protocol with the topical antibiotic Altabax (retapamulin ointment, 1%) to be applied as a thin layer to the anterior nares twice daily for 5 days. After the 5-day treatment is complete, subjects will be retested for the presence of MRSA at day 7, day 12, day 30, and day 90. For this portion of the study, all cultures will additionally undergo disk susceptibility testing for retapamulin, erythromycin, clindamycin (including D-test), trimethoprim sulfa, and mupirocin (5 mcg and 20 mcg disks). In addition, Etests for retapamulin and mupirocin will be done. Genetic isolates will be characterized by rep-PCR pre-treatment and post-treatment. Data will be analyzed for MRSA prevalence and risk factor associations with MRSA colonization. Of those subjects found to be MRSA positive, data from the follow-up cultures will be used to assess the efficacy of Altabax in clearing MRSA nasal colonization.