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

Area of Science:

• Infectious Diseases
• Microbiology
• Epidemiology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) has transitioned from hospital-acquired infections to community settings globally over the past two decades.
• In France, MRSA prevalence has been low, with outbreaks primarily linked to the ST80 clone.
• Recent emergence of the ST-USA300 MRSA clone, including in pediatric populations, signals a shift in epidemiological trends.

Purpose of the Study:

• To investigate the epidemiological dynamics of MRSA in French pediatric hospitalizations.
• To analyze the prevalence and genetic diversity of MRSA isolates, particularly Panton-Valentine leukocidin (PVL)-positive strains.
• To assess the changing incidence of specific MRSA clones, including ST80 and ST-USA300.

Main Methods:

• Retrospective analysis of 77 MRSA isolates from pediatric patients hospitalized between 2008 and 2013 across three French hospitals.
• Calculation of MRSA incidence rates per 100 admissions.
• Genetic characterization of MRSA isolates, focusing on PVL gene presence and clonal typing (ST80, ST-USA300).

Main Results:

• A stable and low median MRSA incidence of 0.137 per 100 admissions was observed.
• A high prevalence of PVL-positive MRSA (33.8%) was detected among the isolates.
• The predominant PVL-positive MRSA clones were ST80 (46.1%) and ST-USA300 (30.8%), with a notable increase in ST-USA300 incidence over the study period.

Conclusions:

• The emergence and increasing incidence of the ST-USA300 MRSA clone in French pediatric settings warrant attention.
• Enhanced screening for PVL genes in MRSA isolates from abscesses, irrespective of susceptibility patterns, is recommended for early detection.
• Improved surveillance strategies are crucial to monitor and manage the evolving landscape of community-associated MRSA in France.