Methicillin-resistant Staphylococcus aureus outbreak: A consensus panel's definition and management guidelines

Objective: To provide medical personnel with a definition of an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) and guidelines for managing potential outbreaks. Participants: Eighteen panel members were chosen from different specialties, types of institutions, and geographic regions. Representatives from the American Society of Consultant Pharmacists, the American Society of Health-Systems Pharmacists, the Society for Healthcare Epidemiology of America, and the National Association of Directors of Nursing Administration participated. Consensus process: In preparation for the conference, panel members reviewed the literature and wrote abstracts outlining their personal opinions on the core issues, which were circulated to all participants. During a weekend conference, the panel summarized the reviewed literature, defined an MRSA outbreak, and developed management guidelines. Evidence: Published literature, clinical experience, and expert opinion concerning the emergence and subsequent management of MRSA cases in health care institutions. Results: An outbreak of MRSA was defined as either an increase in the rate of MRSA cases or a clustering of new cases due to the transmission of a single microbial strain in the health care institution. An increased rate of cases can be defined statistically or experientially and includes both infected and colonized patients. A potential outbreak should trigger stepwise, multidisciplinary actions consisting of basic epidemiologic procedures (phase 1) to form an initial epidemiologic hypothesis of an outbreak (phase II) followed by a standard epidemiologic workup (phase III) and microbiologic studies (phase IV) to confirm the hypothesis. Mupirocin calcium treatments should be considered to decolonize health care workers during the fourth phase, even before typing is completed. Conclusions: Until studies can be conducted to delineate the effectiveness of different recommendations, the proposed guidelines may provide a useful starting point that can be adapted to meet an individual institution's specific needs.