Group B streptococci, or Streptococcus agalactiae, are the major cause of severe diseases in newborns and adults. The PAI-A and PAI-A1 pathogenicity islands containing the sspB1 and sspB1a genes, respectively, were found among group B streptococci mobile genetic elements. The presence of sspB genes correlates with urogenital tract infections. The aim of this study was to determine the frequency of group B streptococci strains with the PAI-A and PAI-A1 pathogenicity islands, circulating in Moscow, in comparison with strains from St. Petersburg. The sspB1 gene, and hence the PAI-A pathogenicity island, was not found in the genomes of strains from Moscow. The frequency of the sspB1a gene and the PAI-A1 pathogenicity island in the genomes of clinical strains was three times higher than in the genomes of colonizing strains. Thus, it can be assumed that the genes of the sspB family are more specific of group B streptococci colonizing pregnant women and newborns.

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Aim. To approve the COrDIS kit (Gordiz, Russia) for the authenticity of cell lines from the Bioresource Collection of the N.N. Blokhin National Medical Research Center of Oncology by the short tandem repeat (STR) profiling.Material and methods. The chosen method proved to be a reliable and reproducible option. With this approach, a number of polymorphic STR loci are amplified using commercially available primer sets. Polymerase chain reaction (PCR) products are analyzed simultaneously with size standards using automated fluorescent detection methods. The results are presented as a simple number code corresponding to the lengths of the PCR products amplified at each locus. By applying this method to cell lines, the laboratory can both authenticate commercial cell lines and build a database of their lines. In the work, we used the COrDIS EXPERT 26 kit (Gordiz, Russia), validated for molecular genetic identification of personality based on multiplex PCR analysis of 26 highly polymorphic loci of human genomic deoxyribonucleic acid. PCR results were analyzed by capillary electrophoresis using an automatic genetic analyzer with laser-induced fluorescence detection (Applied Biosystems 3500xL).Results. When testing the method, profiling of 37 cell lines was carried out, of which 18 were announced in international databases and 19 were unique, obtained at the N. N. Blokhin National Medical Research Center of Oncology, as well as a cell line mixture in order to determine the limits of contamination detection. The obtained results showed the correspondence of commercial cell lines with the data in international databases. Within the framework of this work, profiles of unique lines were obtained and the foundation of own genetic database was laid. Studies to identify the limit of contamination detection by another line have shown that even 4% of the contaminant culture in the total pool can be used to identify its individual alleles.Conclusion. The results obtained indicate the possibility of using the method to identify samples of the collection and detect intraspecific contamination.