Epidemiological assessment of the effect of circulating genotypes of Mycobacterium tuberculosis and their drug resistance on the epidemic process of tuberculosis in Primorsky Krai

Objective. To identify the spectrum of Mycobacterium tuberculosis genotypes circulating in Primorsky Krai and their significance in shaping the epidemiological situation. Materials and methods . The prevalence of multidrug-resistant tuberculosis (MDR-TB) was assessed based on monitoring data from the Primorsky Regional Tuberculosis Dispensary. To identify the genotypes of Mycobacterium tuberculosis (MTB), DNA was extracted from patient samples obtained at the dispensary’s bacteriological laboratory in 2015–2016. Culture samples were placed in a special preservative and sent to the Laboratory of Epidemiologically and Socially Significant Infections at the Scientific Center for Family Health and Human Reproduction Problems in Irkutsk, Russian Federation, where genotyping was performed using the 24-locus MIRU-VNTR method. A total of 99 DNA samples of M. tuberculosis were used in the study. The sample included both female (38 patients) and male (61 patients) individuals, with a mean age of approximately 41 years. The majority of patients (65 individuals, 65%) were diagnosed with infiltrative tuberculosis. Statistical analysis was performed using standard methods with Microsoft Excel 2010 and Statistica 10 software. Results. The incidence of MDR-TB in the population of Primorsky Krai remains relatively stable, with no significant decrease in its transmission activity. The genotypic structure of Mycobacterium tuberculosis in the region includes six genotypes, with a marked predominance of the Beijing family (Beijing genotype – 72.7%). Strains of the CC2/148 subtype belonging to the Beijing family demonstrated a statistically significantly higher level of multidrug resistance compared to the CC1 subtype. Conclusion. The high epidemiological significance of MDR-TB and the predominance of the Beijing family strains with a high level of drug resistance highlight the need to improve epidemiological surveillance of tuberculosis in Primorsky Krai