[Efficacy and safety of vaccines against tuberculosis in the relation to genetic variability of Mycobacterium bovis BCG strains].

All vaccines against tuberculosis used actually over the world contain Mycobacterium bovis BCG strains (Bacillus Calmette-Guerin) as active substance. Strain BCG, that was obtained in 1921 by Calmette and Guerin after 13 years ofpassaging on the potato-glicerol medium with addition of bile, was distributed to many laboratories for vaccine production. The repeated passages of M. bovis BCG strain in different culture conditions caused the numerous mutations and formation of many BCG substrains that differed according to efficacy and safety. The review of many publications related to genetic differences between BCG substrains was performed for identify the genes responsible for their virulence and protective characteristics. Possibility of development of new generation vaccines against tuberculosis is discussed.