Distribution among Thai children of methicillin-resistant Staphylococcus aureus lacking cna, fnbA and icaAD.

Staphylococcus aureus is a bacterium causing infections in both community and hospitals. S. aureus nasal colonization increases the risk of acquiring S. aureus infection. In this study, the prevalence of S. aureus nasal colonization was determined in Thai children, showing that nasal colonization was found in 78 of 217 subjects and the methicillin-resistant S. aureus (MRSA) carriage rate was present in 5 of 217 children. Among 78 S. aureus isolates, resistance to penicillin, erythromycin, clindamycin, chloramphenicol, trimethoprim/sulfamethoxazole, oxacillin and cefoxitin was found in 99%, 8%, 1%, 4%, 1%, 8% and 6% of the isolates, respectively. The presence of 3 adhesin genes, investigated by PCR, revealed that among 78 isolates, fnbA, icaAD and cna was detected in 73, 72 and 48 isolates, respectively but not in the 5 MRSA isolates. Ninety-five percent and 31% of S. aureus isolates were able to form strong and weak biofilms, respectively. Four MRSA isolates that lacked icaAD were non-biofilm-forming strains. These results revealed a high prevalence of S. aureus nasal colonization in healthy Thai children with 2% being MRSA. Effective strategies to prevent S. aureus transmission and infection are therefore needed in the Thai community.