Retapamulin for Reducing MRSA Nasal Carriage

This study will evaluate the utility of retapamulin, a topical ointment FDA approved for skin infection, as a novel agent for MRSA decolonization and prevention of healthcare-associated MRSA infection. Retapamulin is a first-in-class semi-synthetic pleuromutilin antibiotic that inhibits protein synthesis by interacting with the bacterial ribosome 50S subunit. It received FDA approval in 2007 for the topical treatment of impetigo in adults and pediatric patients. We propose to evaluate retapamulin as an investigational agent for the nasal decolonization of MRSA carriers whose strains demonstrate low-level and high-level resistance to mupirocin. Mupirocin resistance is increasingly common and there is no approved substitute topical agent for decolonization of the MRSA nasal reservoir. We will conduct a randomized placebo-controlled double-blinded study of nasal decolonization with retapamulin vs. placebo for the eradication of MRSA nasal carriage among adult carriers with low-level (MIC 8-256) and high-level mupirocin resistant (MIC \>256) strains. Randomization will be stratified by low vs high level resistance. Consenting adult (at least 18 years old) subjects will be randomized to 1% retapamulin or placebo ointment intra-nasally twice a day for 5 days (D1-5) with follow up bilateral nares swab one week following completion of therapy (\~D12) to assess clearance. If follow up swabs are positive for MRSA, patients will be given a second course of the same agent (retapamulin or placebo) to begin one week following swab collection (\~D19-23) so that up to two decolonization attempts will be made. A final set of bilateral nares swabs will be obtained from all subjects six weeks from the completion of initial treatment (\~D47). Consenting adult (at least 18 years old)subjects will be given retapamulin or placebo. At the time of recruitment, all subjects will complete a detailed survey administered by trained research staff. This survey will include questions related to self care, home hygiene practices, and known risk factors for MRSA acquisition. Subject follow up will include repeat bilateral nares swabs and follow up surveys related to compliance, experience (side effects/concerns) with the assigned regimen, and ongoing risk factors will occur either during a home visit (or facility visit if the patient is admitted to a hospital or nursing home at the time of the required visit) or at the University of California Irvine (UCI) Institute for Clinical and Translational Science (ICTS), a Clinical and Translational Science Award (CTSA) site which provides clinic visit support for pilot studies. Outcomes will include successful nares decolonization at the end of the follow up period (D47). We will detail the sequence of clearance or re-colonization based upon the two follow up nares swabs, as well as any adverse events, which are expected to be related to local irritation in a small percent of subjects.