The incidence of Staphylococcus aureus ST8-USA300 among French pediatric inpatients is rising

Methicillin-resistant Staphylococcus aureus (MRSA) formerly colonized and infected only inpatients in hospitals, but have been reported in community settings worldwide over the last 20 years. In France, the prevalence of such MRSA remains low and outbreaks have, until now, been mainly due to the ST80 clone. However, there were two outbreaks of MRSA clone ST-USA300 recently in France, including one involving children. To investigate epidemiological developments, we studied the 77 MRSA isolated from pediatric patients hospitalized between 2008 and 2013 in three French hospitals. The median incidence of MRSA was stable and low (0.137 per 100 admissions). The prevalence of Panton-Valentine leukocidin (PVL)-positive MRSA was high (33.8 %). The 26 PVL-positive MRSA were genetically diverse, with two clones being predominant: ST80 (12 isolates, 46.1 %) and ST8-USA300 (8 isolates, 30.8 %). The incidence of ST8-USA300 increased over the 6-year period. We believe that screening for ST8-USA300 should be improved: medical biologists should be encouraged to search for PVL genes in all MRSA isolates recovered from abscesses, whatever the susceptibility pattern of the isolate, and not only when suggestive of ST80.