Clinical and genotypic spectrum of SDSE from a tertiary Indian centre: Diversity, virulence, and AMR trends

STREPTOCOCCUS DYSGALACTIAE SUBSP: equisimilis (SDSE) is an emerging pathogen with similarities to S. pyogenes, with limited Indian molecular epidemiological data. This study characterized 55 SDSE isolates via MALDI-TOF and whole genome sequencing for emm typing, MLST, virulence, and antimicrobial resistance profiling. Infections mainly affected diabetic males (mean age 44), commonly presenting as cellulitis or non-healing ulcers. sixteen emm types and 17 STs were identified; with all isolates carrying virulence genes lmb, slo, sagA. The isolates were 100 % penicillin susceptible and 42 % macrolide non susceptible with 53 % mef(A) and 35 % msr(D). Findings stress the need for region-specific genomic surveillance.