Resistance to drugs in tuberculosis develops by the following mechanism:
Strains of M. tuberculosis resistant to individual drugs arise by spontaneous point mutations in the mycobacterial genome that occur at low but predictable rates (10-7-10-10 for the key drugs). The development of drug-resistant TB is invariably the result of monotherapy. Drug-resistant TB may be either primary or acquired. Primary drug resistance is that which develops in a strain infecting a patient who has not previously been treated. Acquired resistance develops during treatment with an inappropriate regimen. Ref: Raviglione M.C., O'Brien R.J. (2012). Chapter 165. Tuberculosis. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.
Transduction
Conjugation
Transformation
Mutation