Multidrug-resistant Myobacterium tuberculosis caused by the Beijing genotype and a specific T1 genotype clone (SIT No. 266) is widely transmitted in Minsk

SETTING: This study was performed in the city of Minsk in Belarus, where a very severe problem with MDR-TB was demonstrated in a recent drug resistant survey. OBJECTIVE: The aim of this study was to use molecular typing of MDR and pan-susceptible clinical isolates of Mycobacterium tuberculosis to increase the understanding of the transmission patterns and possible differences between the strains causing susceptible and drug-resistant tuberculosis. STUDY POPULATION AND METHODS: Consecutive isolates from pulmonary TB patients in Minsk were collected at the Belarusian National Reference Laboratory. Isolates found to be either pan-susceptible or MDR were included in the study, which totally comprised 81 MDR and 82 pan-susceptible clinical isolates. All isolates were characterized by spoligotyping. The major clusters were characterized using sequencing of the pncA gene. RESULTS: Three out of four MDR cases were caused by one out of two drug-resistant clones of M. tuberculosis belonging to the Beijing and T1 genotypes, respectively. A single T1 clone, SIT No. 266, found exclusively in the MDR cohort, was shown to cause no less than 30% of all MDR-TB cases. DISCUSSION: The findings indicate that the major cause of MDR-TB in Minsk is an ongoing transmission of certain already resistant M. tuberculosis strains. CONCLUSION: The significant transmission of MDR-TB in Minsk underlines the urgent need for strengthened infection control measures to limit the transmission in order to better control MDR-TB.