Current Streptococcus Pneumoniae Serotypes in Sverdlovsk Region in 2020–2021

Relevance. Studying the spread of individual S. pneumoniae serotypes is of special epidemiologic and clinical importance. Sverdlovsk Region with the 20% proportion of community­-acquired pneumonia and its proportion among the causes of mortality of up to 70% is of special concern.Aims. Studying the features of the S. pneumoniae serotype landscape in individual socially significant population groups in Sverdlovsk Region in 2020 and 2021.Materials and methods. The work presents the results of testing nasopharyngeal smears collected in two observation groups, namely, that of 159 unvaccinated children aged 0 to 5 with acute respiratory infections (ARI), and that of 392 apparently healthy adults aged 19 to 27. We performed molecular genetic typing for identification of 20 leading S. рneumoniae serotypes/serogroups (1, 2, 3, 4, 5, 14, 16F, 19A, 19F, 23A, 23F, 6ABCD, 7AF, 9AV, 9LN, 11AD, 15AF, 18ABCF, 22AF, 12FAB/44/46, 33AF/37) using multiplex polymerase chain reaction (PCR).Results and discussion. In the individuals of the studied groups of observation, in 27.0% and 28.1% of the cases the study detected the S. pneumoniae in the biological material with circulation of 12 «vaccine» (19F – 2,6%, 6ABCD – 2,6%, 4 – 2,0%, 23F – 2,0%, 9AV – 1,3%, 9LN – 0,6%, 11AD – 1,3%, 18ABCF – 2,0%) and «nonvaccine» (15AF – 0.7%, 16F – 0.6%) serotypes. Nontypable strains with the highest proportion (77.3%) among the immunized adult population were predominant in the structure; in the unvaccinated children, this rate was 53.5%. Among the typable strains in children, 70.0% belonged to the vaccine ones, and most frequently the study identified 19F and 23F serotypes, while serotypes 3 and 12F/A/B/44/46 dominated among the adults.Conclusion. The study of unimmunized pediatric and immunized adult populations of Sverdlovsk Region confirmed a trend toward an increase in the circulation of nontypable S. pneumoniae strains in the Russian Federation, which sets the agenda to improve the monitoring system and optimize molecular genetic techniques for identification of the pathogens and upgrade the present specific and nonspecific preventive remedies, including the current antimicrobial ones and locally­-produced vaccine.