Comparative molecular analysis of meticillin-resistant Staphylococcus aureus isolates from children with atopic dermatitis and healthy subjects in Taiwan.

BACKGROUND: Children with atopic dermatitis (AD) are more frequently colonized by Staphylococcus aureus than healthy children.
OBJECTIVES: To assess whether any relationship exists between nasal meticillin-resistant S. aureus (MRSA) colonization and subsequent skin and soft-tissue infections (SSTI). PATIENTS AND METHODS: From 2005 through 2006, comparative molecular analyses of 23 MRSA-colonizing isolates from 133 children with AD, 44 MRSA-colonizing isolates from 490 healthy controls, and 12 MRSA-infecting isolates from 20 children with AD and concurrent SSTI were conducted.
RESULTS: Nasal MRSA colonization in children with AD was significantly higher compared with normal individuals (17.3% vs. 9.0%; P = 0.01). The molecular characteristics differed significantly between the MRSA isolates from children with AD and the MRSA-colonizing isolates from healthy controls. The clone characterized as sequence type (ST)59 (338)/pulsotype B/staphylococcal cassette chromosome mec (SCCmec) V(T)/Panton-Valentine leucocidin (PVL)-positive/staphylococcal enterotoxin B (SEB)-positive accounted for half of the MRSA isolates from children with AD, and another clone, characterized as ST59/pulsotype A/SCCmec IV/PVL-negative/SEB-positive accounted for 61% of the MRSA-colonizing isolates from healthy controls.
CONCLUSIONS: We found MRSA colonizing the anterior nares of a large number of Taiwanese children, especially among those with AD. Analysis of our data provides evidence that links MRSA-colonizing isolates to MRSA-infecting isolates from concurrent SSTI in children with AD.