Characterization of Streptococcus pyogenes isolates from French children: emm-1 genotype is associated with invasive infections and spread of the M1UK clone

BACKGROUND: The bacterial determinants of Group A Streptococcus (GAS) associated with either invasive (IGASI) or non-invasive (NIGASI) infections remain controversial. METHODS: From 2014 to 2018, French children hospitalized for an IGASI were enrolled in a prospective multicenter study aimed at identifying bacterial virulence factors and predisposing immunologic and genetic factors. During the same period, age- and date-matched control children with NIGASI were enrolled. Whole genome sequencing was performed for all GAS isolates. The 27 specific single nucleotide polymorphisms characterizing the M1UK lineage were searched among the emm-1 isolates. RESULTS: A total of 192 GAS isolates were sequenced: 94 from the IGASI group and 98 from the NIGASI group. The emm-1 genotype predominated in the IGASI group (36% vs. 11% in NIGASI group, P < .05) and was followed by emm-4, emm-12, and emm-3 (12%, 11%, and 10% respectively). In the NIGASI group, emm-89 predominated (21% vs 7% in the IGASI group, P