Nasal carriage of methicillin-resistant Staphylococcus aureus in contacts of an adolescent with community-acquired disseminated disease

Objectives: To assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in contacts after the diagnosis of community-acquired MRSA bacteremia, hip arthritis, pyomyositis and pulmonary septic emboli with necrotizing pneumonia and empyema in a previously healthy female adolescent in Taiwan. Materials and Methods: A nasal culture survey of the 4 household members, 30 classmates and 5 teachers of the index case (class A), 28 classmates of her brother's (class B), as well as 76 health care workers (HCWs), including 58 nurses, 16 doctors and 2 assistants, working in the ordinary wards were performed 1 month after the onset. The clinical isolates from bloodstream and synovial fluid of the index case as well as all the colonized isolates, if identified, were collected and genotyped with pulsed field gel electrophoresis. Results: A total of 15 subjects, including the case patient, her brother, 2 adolescents (6.7%) in class A, 6 children (21.4%) in class B and 5 HCWs (6.6%), were colonized with MRSA. Of the 15 colonizing and 2 clinical MRSA isolates, 4 genotypes with 2 major types were identified. Except for 2 isolates, the remaining 15 isolates were genotype C or D. Both clinical isolates, the isolate from her brother, 3 isolates from the children in class B and 2 isolates from the HCWs belonged to genotype D. Two isolates from the adolescents in class A, the other 3 isolates from the children in class B and 2 isolates from the HCWs were genotype C. The colonized strain from the index case was genotype A. Conclusions: Carriage of MRSA can be identified in a substantial proportion of school children without apparent risk factors in Taiwan. With transmissibility, the carriage of MRSA in school children can accelerate the spread of MRSA in the community.