Decontamination strategies for MRSA-colonized patients

Abstract

Introduction: The fi rst step in the pathogenesis of most skin and soft tissue infections is the colonization of the host by a potential pathogen or pathogens. Staphylococcus aureus has long been an important pathogen, but the dissemination of community-associated methicillin-resistant S. aureus (MRSA) over the past decade, superimposed on the gradually increasing carriage rates of hospital-associated MRSA, have made beta-lactam–resistant S. aureus isolates the dominant etiology of skin and soft tissue infections in many locations across the United States [ 1 ]. The costs of established MRSA infection with regard to prolonged hospital stay, increased mortality, and increased expense have been widely reported [ 2 ], and it is only natural that growing attention has been focused on preventing MRSA infection. Although the anterior nares are the most commonly reported site of MRSA carriage, MRSA may persist in additional sites (eg, skin, chronic wounds, and perianal/rectal carriage) in some individuals or may reside exclusively in sites other than the nares in others. The dynamic aspects of S. aureus carriage are complex: most individuals are transiently colonized for varying intervals, some are persistently colonized at one or more sites when studied longitudinally and a modest fraction of individuals remain persistently culture negative for S. aureus colonization. Several interventional studies have explored the eradication of MRSA carriage. Eradication strategies have tended to use topical agents directed at nares and/or skin decontamination or systemic antibiotics. In general, these studies have been limited by enrollment size, duration of monitoring, and inherent study limitations regarding the distinction in culture-positive patients between decontamination failures and effective eradication followed by acquisition of a distinct MRSA strain.