Virulent Properties of Serotypes of Streptococcus pneumoniae from Child Carriers in the Republic of Tatarstan

The paper covers research results evaluating the occurrence of various serotypes of circulating pneumococcal strains in preschool children in the Republic of Tatarstan in 2017–2018, the dominance of “vaccine” serotypes and the emergence of new “non-vaccine” strains are shown. It has been shown that 86.5% of clinical isolates of Streptococcus pneumoniae from healthy carrier children have pronounced IgA-protease activity. Serotypes 14, 19F, 7F, 23F, 16F have high protease activity. Discrepancies in protein expression between strains with different levels of IgA protease activity were studied using differential gel electrophoresis followed by mass spectrometric identification. Study of the protein expression profiles by gel electrophoresis in S. pneumoniae strains with different proteolytic activity resulted in the identification of 5 protein spots which showed a significant difference in expression (at least a 2-fold change between the two phenotypes).