Why is Mycobacterium Tuberculosis Hard to Grow? The Principle of Biorelativity Explains

Comparing the lifespan and the proliferative potential of E. coli and MTB, we see a reverse relationship. E. coli live short, and grow fast. It just takes 18-20 minutes for them to duplicate. Conversely, MTBs live long, are quite tolerant to different environments, and grow so slowly that their duplication time exceeds 18 hrs. The duplication time of mycobacterium leprae is even longer, so that all the cultivation efforts have failed. Although nobody knows exactly how long these bacteria can live since they cannot be cultivated, it can be postulated that they live very long. That explains why leprosy is so difficult to cure.