Molecular epidemio-logy of tuberculosis in the capital of Prague in 2013 and 2014

Aim: Phylogenetic analysis of Mycobacterium tuberculosis strains by the MIRU-VNTR method and their assignment to lineages and sublineages.

Material and methods: DNA of 132 strains of M. tuberculosis was recovered from patients in the capital of Prague in 2013 and 2014. The MIRU-VNTR method was used. Using the MIRU-VNTRplus website tools, the strains were identified and assigned to genetically related groups.

Results: The highest prevalence of TB was reported in males aged between 45 and 54 years. The isolates of M. tuberculosis show high polymorphism in the number of repetitive sequences. Three global lineages were identified: 1 - Indo-Oceanic, 2 - East-Asian, and 4 - Euro-American, represented by 85.6 % of strains, comprising nine sublineages: Haarlem (40.9 %), H37Rv (25.8 %), S, Cameroon, LAM, X, NEW-1, URAL, and Delhi/CAS. Fully identical repetitive sequences were found in 28.0 % of strains (nine groups) of global lineage 4 - Euro-American, sublineages Haarlem (four groups), H37Rv (three groups), Cameroon (one group), and S (one group). Among the strains analyzed, four multi-drug resistant (MDR) strains were identified without clustering (one in 2013 and three in 2014). Two MDR strains were assigned to Euro-American lineage 4 and two MDR strains to East-Asian lineage 2.

Conclusions: Genotyping of M. tuberculosis strains by the MIRU-VNTR method allows for rapid genetic identification and assignment to lineages and sublineages. The identification of strains of M. tuberculosis, their assignment to lineages, and line-age distribution make it possible to monitor their movement not only within a country but also worldwide. Genotyping data obtained over years make it possible to track the infection source and transmission pathways.