Molecular biological characteristics of Mitis group streptococci

Relevance. Mitis Group Streptococci (SMG), which belong to one of the 5 groups of greening streptococci, are a component of the normal human nasopharyngeal flora and include 17 known species. Among SMG, Streptococcus pneumoniae is the most common cause of a number of invasive and non-invasive human diseases that lead to high mortality rates worldwide. It is interesting to note that a number of studies have shown not only differences, but also similarities in the genes encoding the pathogenicity factors of S. pneumoniae and other members of the SMG, particularly Streptococcus oralis. Aims. To analyze and summarize the results of molecular genetic studies of the SMG and identify the features of the genetic diversity of the pathogen strains. Conclusion. The comparative analysis of the genomes of closely related SMG species revealed key common genes encoding the main pathogenicity factors, which allows for the optimization of the selection of candidate strains for development.