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where direct contact with a draining skin lesion results in immediate infection without intervening colonization. In an illustrative case series involving the St. Louis Rams during the 2003 season, eight CA-MRSA infections (caused by a single clone) occurred in ďŹ ve St. Louis Rams linemen. A meticulous investigation revealed no nasal colonization among any players or trainers. It was theorized that CA-MRSA may have spread among lineman by direct contact between susceptible turf burns and draining infections, shared towels, or the unwashed hands of trainers [21]. Risk groups in which CA-MRSA outbreaks have occurred and demographic and clinical risk factors for CA-MRSA infection are listed in Box 1. It is apparent from this list that physical crowding and hygiene play significant roles in determining risk for CA-MRSA infection. Unfortunately, the utility of risk factors for identifying likely MRSA SSTIs appears limited in view of the very high overall MRSA prevalence in this infection type. On the other hand, for infections like community-acquired pneumonia (CAP), where CA-MRSA is an infrequent but possible pathogen, using risk factors to help identify patients who deserve empiric therapy for MRSA makes sense. Antibiotic susceptibility The usual antibiotic susceptibility pattern of CA-MRSA is summarized in Table 1. Treatment recommendations are covered in detail below under
Box 1. Risk factors associated with community-acquired methicillin-resistant Staphylococcus aureus infection and risk groups in which clusters of infection have been reported Infection type being a furuncle Household contacts of a confirmed case Jail detainees Military recruits Children attending daycare centers Participants in contact sports (eg, American football, fencing) Urban dwellers of low socioeconomic status living in crowded conditions Tattoo recipients Homeless youth Men who have sex with men HIV-infected individuals Pregnant and postpartum women Healthy newborns African Americans Pacific Islanders Native Americans