Most Mycobacterium species, including most clinically relevant species, can be cultured in blood agar.[7] However, some species grow very slowly due to extremely long reproductive cycles — M. leprae, may take more than 20 days to proceed through one division cycle (for comparison, some E. coli strains take only 20 minutes), making laboratory culture a slow process.[1] In addition, the availability of genetic manipulation techniques still lags far behind that of other bacterial species.