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Background. The B0/W148 subtype belongs to the L2phylogenetic lineage of Mycobacterium tuberculosis and is most common in the former Soviet Union. Test systems capable of detecting genetic variants of the pathogen are needed for effective epidemiological surveillance. Studying the genetic diversity of B0/W148 strains and finding molecular markers suitable for their genotyping are key steps in the development of such diagnostic tools.The aim of the work. To study the phylogenetic diversity of the B0/W148 subtype circulating in the territory of the Russian Federation and neighboring countries in order to identify unique clades and search for specific molecular markers suitable for their precise identification.Materials and methods. The study used DNA samples of B0/W148 strains (n = 34) isolated in different regions of the Russian Federation, as well as genomic data obtained from the SRA NCBI (Sequence Read Archive of the National Center for Biotechnology Information) (n = 419). Phylogenetic analysis and principal component analysis (PCA) of whole genome sequencing (WGS) data were used to analyze genetic diversity and to identify molecular markers. An evolutionary reconstruction of the age of the identified clades was carried out.Results. The analysis of the B0/W148 genomes (n = 453) revealed that they are divided into three phylogenetic clades: B – basal, M – minor and P – principal. It was found that specific mutations in the M and P clades allow for their differential diagnosis. The 4137219T>G mutation is unique for the M clade, and the 2241091C>T mutation is unique for the P clade. No characteristic mutations were found among the strains of B clade. In addition, unique mutation profiles in the genes responsible for drug resistance were identified for the clades.Conclusion. The study showed that B0/W148 strains represent a genetically heterogeneous population divided into B, M and P clades. M and P Clades have unique mutations that allow for their identification. It was also found that all clades are characterized by the presence of specific mutation profiles in drug resistance genes.

Introduction. Fluoroquinolones remain the key second-line anti-tuberculosis drugs. The aim of the study was the molecular characterization of fluoroquinolone-resistant Mycobacterium tuberculosis strains from newly diagnosed tuberculosis patients in the Northwest of the Russian Federation. Materials and methods. The retrospective study collection included M. tuberculosis isolates isolated in 2015–2019 from previously untreated tuberculosis patients. Susceptibility to antituberculosis drugs (including the fluoroquinolone ofloxacin) was determined using the BACTEC MGIT960 or absolute concentration method. Mutations in the gyrA gene as a marker of resistance to fluoroquinolones, were detected by real-time PCR. Beijing genotype and its subtypes were detected by PCR and real-time PCR methods. Non-Beijing strains were spoligotyped. Results and discussion. Phenotypic resistance to ofloxacin was detected in 6.7% (40/599) of strains and in 17.4% (40/230) of MDR strains. 34 of 40 (85%) ofloxacin-resistant strains belonged to the Beijing genotype. 18 (45%) strains were assigned to the Russian epidemic subtype Beijing B0/W148 and 12 (30%) to Beijing Central Asian/Russian. The remaining 6 ofloxacin-resistant strains belonged to the Euro-American phylogenetic lineage. Mutations in the gyrA gene were found in 97.5% (39/40) of strains. The most common were mutations in codon 94 (69.2%, 27/39). The Asp94Gly substitution was identified in 57.5% (23/40) of ofloxacin-resistant strains and was dominant among Beijing (19/34) and non-Beijing (4/6) strains. The second most common substitution was Ala90Val (25%, 10/40). More than half of the ofloxacin-resistant strains, Beijing B0/W148 (10/18) and Central Asian/Russian (7/12), carried the Asp94Gly mutation. Conclusion. In the Northwest of Russia in 2016-2019, primary resistance of M. tuberculosis to fluoroquinolones was 6.7% in the total collection and 17.4% of MDR strains, and was mainly caused by the gyrA Asp94Gly and Ala90Val mutations. Beijing B0/W148 genotype was characterized by the largest proportion of fluoroquinolone-resistant strains.

Objective To understand the molecular characteristics of Streptomycin (SM) resistance in multidrug-resistant tuberculosis (MDR-TB) in Jiangxi Province, and to explore the relationship between SM resistant genes (rpsL, rrs and gidB) mutations and SM resistant phenotypes in Beijing genotype TB. Methods 106 non-replicated MDR-TB isolates were collected from Gaoxin Branch of The First Affiliated Hospital of Nanchang University and Jiangxi Provincial Chest Hospital from January to December 2021, and tested for drug-resistance phenotypes, whether they were Beijing genotype or not and the characteristics of rpsL, rrs and gidB gene mutations. Chi-square test was performed to determine whether rpsL, rrs and gidB mutations were related to genotypes and drug-resistance phenotypes. Results Among 106 cases of MDR-TB, 76 cases were resistant to SM. A total of 58 cases had rpsL 43A > G mutation, 8 cases had 88A > G mutation, 5 cases had rrs mutation, and 3 cases had gidB mutation. Statistical analysis showed that the coincidence rate of gene mutation and phenotypic drug-resistance detection was 89.6%, and the specificity and sensitivity were 86.7% and 90.8%, respectively. The isolated rate of Beijing genotype TB was 88.7%, and the drug-resistant gene mutations were mainly concentrated in rpsL and rrs, while the drug-resistant mutations of non-Beijing genotype were mainly concentrated in gidB；in addition, Beijing genotype bacteria were more prone to gene mutations (P = 0.013), but there was no difference in phenotypic drugresistance. Conclusions Mutations in rpsL, rrs, and gidB genes have a good coincidence rate with phenotypic drug-resistance, and molecular biology can be used to detect directly drug-resistance genes to predict bacterial resistance；TB genotypes are strongly associated with streptomycin resistance characteristics. [ABSTRACT FROM AUTHOR]

The Beijing genotype is the most distributed M. tuberculosis family in Kazakhstan. In this study, we identified dominant Beijing clusters in Kazakhstan and assessed their drug susceptibility profiles and association with the most widely spread mutation Ser531Leu of the rpoB gene and the mutation Ser315Thr of the katG gene associated with resistance to rifampicin and isoniazid, respectively. M. tuberculosis isolates (n = 540) from new TB cases were included in the study. MIRU-VNTR genotyping was performed for 540 clinical isolates to determine M. tuberculosis families using 24 loci. RD analysis was additionally performed for the Beijing isolates. The identification of mutations in the drug-resistance genes of M. tuberculosis was performed with allele-specific real-time PCR and Sanger sequencing. The Beijing genotype was identified in 60% (324/540) of the clinical isolates. Central Asian/Russian cluster 94-32 was the most distributed cluster among the Beijing isolates (50.3%; 163/324). Three other dominant Beijing clusters were identified as 94-33 (3.4%; 11/324), 100-32 (3.1%; 10/324) and 99-32 (3.1%; 10/324). The Beijing genotype was associated with drug-resistant TB (p < 0.0001), including multidrug-resistant TB (p < 0.0001), in our study. An association of the mutation Ser531Leu of the rpoB gene with the Beijing genotype was found (p < 0.0001; OR = 16.0000; 95%CI: 4.9161–52.0740). Among the Beijing isolates, cluster 94-32 showed an association with MDR-TB (p = 0.021). This is why the evaluation of the Beijing genotype and its clusters is needed to control MDR-TB in Kazakhstan. [ABSTRACT FROM AUTHOR]

A total of 397 strains of Mycobacterium tuberculosis isolated from newly diagnosed patients with pulmonary tuberculosis in the Omsk oblast in 2019–2020 were genotyped. The prevalence of the Beijing genotype strains (70.8%), in particular, of two modern sublineage clusters: Central Asian/Russian (46.1%) and B0/W148 (19.1%), was established. Strains of the ancient sublineage of the Beijing genotype were represented by clusters 1071-32 and 14717-15, totaling 4.8%. Compared with other genotypes, the strains of B0/W148-cluster and the ancient Beijing sublineage were more often characterized by multidrug resistance (MDR): 93.4 and 94.7%, respectively (P < 0.0001). Among members of other genetic families (LAM, Ural, T, Haarlem), drug-sensitive strains predominated (75.0%). The circulation of MDR Beijing strains requires molecular epidemiological surveillance in view of their possible wider spread. [ABSTRACT FROM AUTHOR]

The Beijing genotype of Mycobacterium tuberculosis (Mtb) has sparked debate regarding its virulence and transmissibility. This study contributes to this discussion by assessing its effect on the risk of latent tuberculosis infection (LTBI), active tuberculosis (TB) disease among contacts, and clustering of known TB cases. We conducted a retrospective cohort study using the records of 4457 culture-confirmed TB patients and their contacts (20,448) reported to the Florida Department of Health between 2009 and 2023. Univariate and multivariate analyses were used to evaluate the effect of the Beijing strain on LTBI, active TB risk among contacts, and case clustering. Our study revealed no significant difference in transmissibility between the Beijing and non-Beijing genotypes among contacts. LTBI prevalence was 19.9%, slightly higher in non-Beijing than Beijing genotypes (20.2% vs. 15.5%, p < 0.001). The prevalence of active TB was 1.8%, with no significant difference between the Beijing and non-Beijing genotypes (1.4% vs. 1.8%, p = 0.296). Increased LTBI risk was associated with older age, male sex, Hispanic ethnicity, multidrug-resistant TB exposure, household exposure, and a longer exposure duration. Active TB risk was higher for males, HIV-positive individuals, and contacts with more prolonged exposure to index cases. The Beijing genotype was associated with increased TB case clustering (aOR = 1.98, 95%CI: 1.53, 2.55, p < 0.001) as compared to the non-Beijing genotypes. US birthplace (aOR = 2.75, 95%CI: 2.37, 3.19, p < 0.001), pulmonary disease (aOR = 1.27, 95%CI: 1.04, 1.56, p < 0.020), cavitary TB (aOR = 1.25, 95% CI: 1.08, 1.44, p < 0.003), previous year alcohol use (aOR = 1.68, 95%CI: 1.38, 2.04, p < 0.001), and recreational drug use (aOR = 1.32, 95%CI: 1.04, 1.67, p < 0.024) were also associated with an increased risk of TB case clustering. While the Beijing genotype did not increase the risk of LTBI or active TB among contacts, it showed a higher tendency for case clustering. Hence, interventions should prioritize populations where this genotype is prevalent. • Large study of TB cases (4457) categorized into Beijing (337) and non-Beijing (4120) genotypes, with their contacts (20,448) • No significant difference in the rate of transmission between the Beijing and non-Beijing genotypes among contacts • Beijing Mtb lineage is associated with increased clustering of TB cases • Findings provide insights into strain heterogeneity effects on TB epidemiology and transmission [ABSTRACT FROM AUTHOR]

More than a quarter of the world's population is infected with Mycobacterium tuberculosis . However, only about 10% of those infected develop active TB. This indicates a key role for innate immunity in limiting M. tuberculosis replication. Most often, bacteria can regulate the expression of host-specific molecules and weaken host immunity., Objective: To use a biological model, in order to determine significant molecular immunohistochemical markers characterizing the virulence of the "Buryat" and "Omsk" subtypes of the M. tuberculosis Beijing genotype in lung tissue., Material and Methods: Lung samples of the C57BL/6 male mice were obtained during experimental infection with M. tuberculosis strains: the reference laboratory strain H37Rv, multidrug-resistant clinical strains 396 (highly lethal and hypervirulent «Buryat» genotype Beijing 14717-15) and 6691 (low-lethal and low-virulent "Omsk" genotype Beijing 1071-32) on days 14, 21, 60 and 120. They were studied by histological and immunohistochemical methods. The relative areas of expression of IL-6, IL-12A, iNOS, and TNF- α in the lung tissue of model animals were established., Results: A study of strain 396 showed that both disease progression and damage to lung tissue are associated with a highly reactive immune response and increased synthesis of iNOS and strain characteristics that block the production of TNF- α . On the contrary, for strain 6691 a low reactivity of the immune response was revealed, with statistically significantly lower values of the relative area of expression of NOS and TNF- α during all observation periods (days 14-120). All animals that survived to day 120 showed a similar morphological picture with differences in cytokine levels, indicating a nonlinear relationship between proinflammatory factors and the damage substratum., Conclusion: The progression of the disease and damage of lung tissue were associated with a highly reactive immune response and increased synthesis of iNOS, strain properties that block the TNF- α production. Thus, iNOS and TNF- α can act as molecular markers characterizing the virulence of the "Buryat" and "Omsk" subtypes of M. tuberculosis in lung tissue.