Strategies Employed to Evade the Host Immune Response and the Mechanism of Drug Resistance in Mycobacterium tuberculosis: In Search of Finding New Targets

The partial effectiveness of the host immune response to M. tuberculosis drives bacteria into a latent state, but it is difficult to eliminate the bacteria completely. Usually, this latent condition of M. tuberculosis is reversible, and reactivation of tuberculosis is the leading cause of the majority of transmission. A number of studies performed on animal models and humans have not yet provided a detailed understanding of the mechanisms or correlates of immunity of M. tuberculosis infection or why there is a significant immunity failure to remove the pathogen. Moreover, the mechanism of resistance involved in drug-resistant M. tuberculosis leads to the emergence of strains of bacteria that show significant resistance to the majority of anti-tuberculosis drugs. We have also provided the recent findings and trends regarding the development of new drug molecules to treat drug and multidrug-resistant tuberculosis and the advancements in immunotherapy in the treatment of drug-resistant tuberculosis. This article provides an in-depth and critical analysis of various strategies employed by the drug-resistant M. tuberculosis to escape the host immune response. This bacterium persists in the host for a longer period of time and leads to the development of tuberculosis infection. Furthermore, we also discussed the new targets for the effective treatment of drug-resistant tuberculosis.