Abstract 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.05). Among the 45 emm-1 isolates, 12 (27%) carried the mutations characterizing clone M1UK in both groups (7 in IGASI group and 5 in NIGASI group). The superantigenic toxins SpeA and SpeJ, SIC protein and FCT type 1 pilus predominated in the IGASI group but were linked to emm-1 strains. Insertions/deletions in the covS regulator gene were observed in 5 invasive isolates versus 1 non-invasive isolate. Conclusions Genotype emm-1 GAS strains remained the main cause of invasive infections in French children, associated to specific GAS virulence factors and should be monitored together with the rapid spread of the M1UK lineage. Brief Description emm-1 GAS strains remained the main cause of invasive infections in French children, and 27% were from the M1UK lineage. The superantigenic toxins SpeA and SpeJ, SIC protein and FCT type 1 pilus were significantly associated with invasive infections but were linked to emm-1 strains.
Bidet et al. (2026) studied this question.