Prevalence of community-acquired methicillin-resistant Staphylococcus aureus colonization in a random sample of healthy individuals

Background. Concern has recently arisen that the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization among populations at low risk for acquiring this pathogen has been increasing. Although previous studies have reported on the prevalence of MRSA colonization, most of these studies have been performed in healthcare settings, with few studies performed in the community among healthy individuals in nonhealthcare locations. Objectives. To determine the prevalence of community-acquired ( CA) MRSA colonization in a random sample of healthy individuals in 4 nonhealthcare locations and to compare the genetic similarity between these CA isolates and nosocomial MRSA isolates. Design. Prospective, observational study conducted from October 2004 through February 2005. Setting. Two colleges, 1 church, and 1 restaurant in Newark and Wilmington, Delaware. Participants. A total of 295 healthy volunteers. Results. The rate of S. aureus colonization was 26.8%. Of the 79 S. aureus isolates analyzed, 3 (4%) were resistant to methicillin. Ribotyping of the 3 MRSA isolates showed that they were genetically distinct from each other. Each of the 3 CA isolates were genetically indistinguishable from 3 different nondominant clusters of MRSA isolates found in the medical and surgical intensive care units of Christiana Care Health System ( Newark) and Wilmington Hospital (Wilmington). Conclusion. The overall prevalence of CA-MRSA colonization in a random sample of healthy individuals in 4 nonhealthcare locations in Newark and Wilmington was 1.0%. Despite concerns that the prevalence of MRSA colonization is increasing, it still remains relatively low in our community, perhaps because CA-MRSA colonization tends to occur in clusters.