2014 Volume 24 Issue 1 Pages 10-14
Staphylococcus aureus causes 50% of chronic otitis media (COM) cases. We postulated that population structure of S. aureus is based on geographical location or diseases such as impetigo and atopic dermatitis. We studied whether a lineage causing COM reflected a population structure of S. aureus in the research area or specific to the disease. Between Jan. 2010 and July 2012, 35 strains of S. aureus, including 11 MRSA isolates were collected from patients with COM following tympanoplasty. Phylogenetic analysis was performed using multilocus sequence typing (MLST). In COM, the most prevalent clonal complex (CC; lineages sharing: at least 5 of 7 house-keeping genes in MLST) was CC5 (23%), followed by CC8 (17%). Prevalence of CC5, which included MRSA isolates, in COM was significantly greater than in healthy volunteers (P<0.001, Chi-square for independence test). Prevalence of CC59, CC75, and CC121, which are minor strains in nasal cavities, was also greater in COM patients. In contrast, prevalence of CC188 and CC508, which are major strains in nasal cavities, were lower in COM patients. This study demonstrated that S. aureus types were disease specific and genotypes from COM patients did not correspond to those of nares from healthy volunteers.
