Molecular characteristics and clinical features of pediatric methicillin-susceptible Staphylococcus aureus infection in a medical center in northern Taiwan.

BACKGROUND: There have been no reports regarding clinical features and molecular characteristics of childhood methicillin-susceptible Staphylococcus aureus (MSSA) infections in Taiwan. METHODS: We prospectively collected clinical S. aureus isolates from patients aged < 18 years in a university-affiliated hospital in 2015. Only the first isolate from each patient was included. Medical records were retrospectively reviewed. Patients were classified as community-associated (CA) or healthcare-associated (HA) by the epidemiologic criteria. All MSSA isolates were molecularly characterized. RESULTS: A total of 495 S. aureus isolates were identified, and 178 (36.0%) were MSSA. Among the 131 MSSA-infected patients enrolled, 94 (71.8%) were community-associated and 60 (45.8%) were inpatients. Patients with HA infections was significantly younger than those with CA infections (median, 15 vs. 67.5 months). The most common specimen of MSSA identified was pus or wound (73.3%). Compared to HA-MSSA, CA-MSSA isolates were significantly less frequently from sputum (6.4% vs. 27%, p = 0.001). Nineteen pulsotypes were identified. Four pulsotypes accounted for 60% of the isolates. Isolates of ST15/pulsotype F were more frequently seen in CA than in HA (p = 0.064) while isolates of ST188/pulsotype AX frequently seen in HA (p = 0.049). PVL genes were identified in 11 isolates (8.4%), nine of which were characterized as ST59/pulsotype D, same as the local endemic CA-MRSA clone. CONCLUSIONS: MSSA accounted for around one-third of childhood S. aureus infections in northern Taiwan. SSTI was the most common manifestation. The molecular characteristics of these clinical MSSA isolates were relatively diverse and had certain significant differences between CA and HA isolates.