Prevalence of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in the community

Recent reports indicate that community-acquired methicillin-resistant Staph ylococcus aureus (MRSA) infections are increasing and may now involve perso ns without risk factors predisposing for acquisition. To estimate the exten t of community MRSA in New York City the prevalence of S. aureus and MRSA n asal colonization in a well-patient population of 500 children and guardian s was determined. The prevalence of S. aureus nasal carriage was 35% for ch ildren and 28% for guardians. One person with predisposing risk factors was colonized with an MRSA, which was identified as the predominant clone foun d in New York City hospitals. A high degree of methicillin-susceptible S. a ureus strain diversity was noted, with no apparent selection for specific c lonal types. Thus, MRSA colonization is not ubiquitous in persons without p redisposing risk outside of the health care environment, Bacterial competit ion and a lack of strong selection may limit the community spread of MRSA a nd can account for its sporadic distribution.