Molecular Genetic Characteristics of Mycobacterium tuberculosis Isolates from Patients with HIV-Associated Tuberculosis

The objective: to provide molecular genetic characteristics of Mycobacterium tuberculosis isolates from patients with HIV-associated tuberculosis. Subjects and Methods . Two groups of M. tuberculosis isolates were included in the study: 103 isolates from patients undergoing treatment for generalized tuberculosis with concurrent HIV infection, and 61 isolates from autopsy specimens of patients who had suffered from generalized tuberculosis and HIV infection. The Beijing genotype of M. tuberculosis isolates, its subtypes and major Russian subtypes were identified by PCR and real-time PCR methods based on the analysis of specific markers and genome loci (dnaA-dnaN::IS6110, Rv2664-Rv2665::IS6110, sigE, NTF, RD181). Genotyping of non-Beijing isolates was performed by spoligotyping followed by comparison with SITVIT2. The results were compared to the published data on the genetic diversity of M. tuberculosis in the North-West of the Russian Federation. Results . In both groups, a predominance of isolates of the Beijing genotype was detected (89.3% and 70%, respectively), among which the majority belonged to subtypes 94-32 (51% and 44.1%) and B0/W148 (41.3% and 30%) related to the modern subline of the Beijing genotype. Some of the isolates belonged to the ancient subline of the Beijing genotype (8.7% and 4.6%). When compared to previously obtained data for the North-West of the Russian Federation, the proportion of MTB isolates of ancient subline from HIV-infected patients was significantly higher than among isolates isolated from HIV-negative patients (6.7% vs. 1.6%, P = 0.0028).