Relation between types and virulence gene profiles among Bulgarian clinical isolates.

The gene, which encodes M protein, is an important epidemiological marker. The aim of this study is to determine the genotypes of Bulgarian clinical streptococccal isolates in 2014-2018 and to evaluate their relationship with virulence genes profiling and disease types. PCR and sequencing were used for genotyping of 182 clinical isolates according to the protocol of the Centre for Disease Control and Prevention. PCR was used to investigate the virulence factors. We identified 15 types and eight clusters. Five main clusters with eight types were predominant: cluster A-C3 () - 24.7%, A-C5 () - 19.2%, E1 () - 11.0%, A-C4 () - 11.0% and E4 () - 20.9%. There were two novel subtypes: and . The investigated strains with genotypes were common in sterile site infections (invasive ones) and types and in skin and mucosal infections. More than 60% of the major cluster A-C3 () members possessed many genes for streptococcal pyrogenic exotoxins that act as super-antigens and bring about potentially higher virulence. : The present study described two novel 3 subtypes. To the best of our knowledge, this study is the first that describe the type spectrum of Bulgarian clinical isolates and associated virulence factors. Monitoring of the pathogenic potential and epidemiology can lead to better knowledge and higher possibility for prevention and eradication of complications of streptococcal infections.