Evaluation of Epidemiological Manifestations of Tuberculosis and Genetic Diversity of Mycobacterium tuberculosis Strains with Multiple Drug Resistance in the Omsk Region

Background . The prevalence of multidrug-resistant tuberculosis poses a serious public health problem, hampering the success of tuberculosis control programs around the world. Aim : Evaluation of epidemiological manifestations of tuberculosis and molecular genetic characteristics of Mycobacterium tuberculosis strains with multiple drug resistance circulating in the Omsk region. Materials and methods . In accordance with the generally accepted algorithm of descriptive and evaluative epidemiological research, the incidence and prevalence of tuberculosis in the Omsk region for the period 2009–2023 were studied. The material for the study was the data from official statistical observation forms. A total of 595 strains of M. tuberculosis isolated from newly diagnosed patients with TB in the Omsk region in the period from 2019–2022 were studied. Cultivation of M. tuberculosis, determination of drug susceptibility, and DNA isolation were carried out using standard methods. Belonging of the strains to the Beijing genotype, its sublineages and clusters was determined using PCR based on the analysis of specific markers. Non-Beijing strains are spoligotyped. Results . In the Omsk region, the dynamics of tuberculosis incidence and prevalence of tuberculosis were characterized by a pronounced downward trend, reaching 43,7 and 66,8 per 100 thousand, respectively, in 2023. The prevalence of multidrugresistant tuberculosis remains significant (22,6 cases per 100 thousand population), and the proportion of MDR tuberculosis cases among newly diagnosed patients increased from 13,1% in 2009 to 28,4% in 2023. In the sample set of strains, 40,5% had MDR, 13,2% had pre-XDR. Genotyping of MDR (including pre-XDR) M. tuberculosis strains revealed the prevalence of the Beijing genotype (86.3%), in particular the subtypes: B0/W148 (38,2%), Central-Asian/Russian (34,4%), as well as clusters 1071-32 (10,0%) and 14717-15 (2,1%) of the ancient sublineage. The most numerous among the non-Beijing was the SIT262 spoligocluster (5,0%) of the Ural genotype. Conclusion . Against the background of a significant decrease in the prevalence and incidence of tuberculosis, the proportion of newly identified MDR-TB strains has increased. At the same time, molecular genetic monitoring of M. tuberculosis has revealed the key role of B0/W148 and Central-Asian/Russian Beijing subtype strains in the spread of MDR-TB. The results obtained demonstrate the spread of multidrug-resistant strains, providing information for making clinical and management decisions in the implementation of regional tuberculosis control programs.