A comparison of adult and pediatric methicillin-resistant Staphylococcus aureus isolates collected from patients at a university hospital in Korea

Abstract

In this study, we compared the phenotypic and genotypic characteristics of 138 MRSA isolates obtained from adult and pediatric patients (adult, 50; children, 88). The resistance rates against gentamicin, clindamycin, and ciprofloxacin were much higher in the adult MRSA isolates than in the pediatric MRSA isolates. The ermC gene, which is responsible for inducible clindamycin resistance, was detected in 52(59.1%) of the 88 pediatric MRSA isolates but in only 5(10.0%) of the 50 adult MRSA isolates. MRSA isolates of clonal type ST5 with an integration of SCCmec type II/II variants was the most predominant clone among the adult isolates, while clonal type ST72 with an integration of SCCmec IV/IVA was the most predominant clone among the pediatric MRSA isolates. Staphylococcal enterotoxin A and toxic shock syndrome toxin-1 were prevalent among the adult MRSA isolates but not among the pediatric MRSA isolates. The results of this study demonstrated remarkable differences between adult and pediatric MRSA isolates in terms of their antimicrobial susceptibility profiles, SCCmec type, multilocus sequence type, staphylococcal toxin genes, and erythromycin resistance genes.