Circulation of <i>Mycobacterium tuberculosis</i> strains of the Beijing Central Asian Outbreak genotype in the Kemerovo region — Kuzbass in 2018–2022

Introduction. The Kemerovo region — Kuzbass is characterized by a high prevalence of multidrug-resistant (MDR) tuberculosis (TB), including coinfection with HIV (HIV/TB). A previously unknown in Russia relationship between MDR and the Beijing Central Asian Outbreak (CAO) subtype has been discovered, which updates studies of Mycobacterium tuberculosis taking into account this resistant variant. Objective: to study the molecular genetic structure of the M. tuberculosis population, to assess the prevalence and possible routes of emergence of Beijing CAO strains in the Kemerovo region — Kuzbass. Materials and methods. A total of 325 M. tuberculosis strains were studied in 2018–2022 using spoligotyping, MIRU-VNTR 24 and SNP typing. Whole genome sequencing and bioinformatics analysis were performed for seven Beijing CAO strains. Results. Primary MDR and pre-extensive drug resistance (pre-XDR) were detected in 39.4% and 11.5% of strains, respectively. In the total sample, MDR was 43.4%, pre-XDR — 19.7%. In the structure of the M. tuberculosis population, the Beijing genotype prevailed (78.8%), with its subtypes Central Asian Russian (40.9%) and B0/W148 (32.6%). The Euro-American lineage (27.3%) was represented by the genotypes T (6.5%), LAM (5.8%), Ural (4.9%), H (0.9%); one strain CAS1-Delhi was detected, the genotype of 2.8% of strains was not identified. The proportion of Beijing CAO was 12.6% of the total sample; this subtype was significantly more often detected among HIV/TB (20.6%) than in HIV-negative TB patients (9.1%; p = 0.005). The results of the Beijing CAO genome analysis from the Kemerovo region indicate the absence of a direct chain of transmission between these TB cases. A hypothesis has been put forward about the introduction of Beijing CAO to the Kemerovo region from Central Asia and its endemic circulation in the region. Conclusion. A high level of MDR and pre-XDR was detected in Beijing genotype strains in the M. tuberculosis population of the Kemerovo region — Kuzbass, especially the B0/W148 (97.2%) and CAO (87.5%) subtypes. Beijing CAO strains, detected mainly in newly diagnosed HIV/TB patients, require further monitoring and control of their spreading.