Molecular identification of M. bovis BCG by Multiplex PCR

Mycobacterium bovis (M. bovis) BCG belongs to Mycobacterium tuberculosis complex (MTBC), highly relatedorganisms, which are 99.9 % similar at nucleotide level and phenotypically similar. Its differentiation from other membersof MTBC by conventional methods is laborious and time consuming. PCR provides a rapid alternative method fordifferentiation between members of MTBC. It depends on identification of region of difference (RD) which have beenlost during attenuation of M. bovis. Two different BCG strains (from two sources) were confirmed as a member of M.tuberculosis (MTB) complex (MTC) and as BCG strains by PCR using primers to a region of the 16S rRNA gene that isconserved in all mycobacteria and region of difference (RD1, RD4, RD9 and RD12) respectively. DNA of Mycobacteriumtuberculosis was used as a control to compare with BCG strains. The results showed that 16S rRNA gene was present inall tested strains, while the RD1, RD4, RD9 and RD12 were absent only in BCG strains