[Preponderance of Mycobacterium tuberculosis strains of the family Beijing and risk factors of their transmission in the Samara Region].

Current molecular and epidemiological studies could reveal individual families of Mycobacterium tuberculosis strains. The purpose of the present study was to reveal the spread of Mycobacterium tuberculosis strains of the family Beijing in the Samara Region and to define risk factors for their transmission. This was a cross-sectional populational molecular epidemiological study that showed that the Beijing genotype prevailed among the obtained isolates (66.6%; 586/880) and it was encountered among convicts and young persons (RR 1.3; 95% CI 1.2-1.5 and RR 1.2; 95% CI 1.0-1.3, respectively), which is indicative of active and recent transmission. Multifactorial analysis indicated that male sex (OR 1.5; 95% CI 1.1-1.9), younger age (OR 1.3; 95% CI 1.1-1.7), homelessness (OR 5.6; 95% CI 1.1-6.3), and prior or current confinement (OR 2.0; 95 CI 1.5-2.7) were substantially associated with the risk of contamination with the strain of the Beijung family. Drug resistance, including multidrug resistance, was twice higher among the strains of this family.