Invasive group A streptococcal infection in children: clinical manifestations and molecular characterization in a French pediatric tertiary care center.

Invasive group A streptococcal (GAS) infections have a broad and evolving clinical spectrum, associated with various GAS genotypes and/or virulence factors that are only poorly described in children. We aimed to assess the clinical and molecular characteristics of invasive GAS infections in 28 children admitted from 2000 to 2007 at a large French pediatric tertiary care center. The GAS isolates were characterized molecularly by emm-typing and by the determination of the main virulence factors: speA, speB, speC, smeZ-1, ssa, sic, and silC. The median age of the children was 2.9 years. Osteoarticular infection (OAI) was the main clinical manifestation (n=15/28, 53%). emm-1 predominated (n=10/28), followed by emm-12, 3, and 4. No significant correlation was found between emm type and clinical manifestations, but emm-1 predominated in cases of OAI (n=7/15) and was associated with speA, speB, smeZ-1, and sic virulence factor genes. In this pediatric study, we describe a predominance of OAI associated with emm-1 GAS. Further larger international pediatric studies, including host immunity evaluation, are needed in order to better assess the pathogenesis of GAS infection in children.