Recent advances in multi-drug-resistant tuberculosis and RNTCP

Tuberculosis (TB) persists as a global public health problem of serious magnitude requiring urgent attention. Current global efforts to control TB have three distinct but overlapping dimensions: humanitarian, public health, and economic. Alleviating illness, suffering, and death of individuals due to TB is the major humanitarian concern for a patient-centered approach to TB control. The public health dimension concerns proper diagnosis and treatment of patients with TB to decrease disease transmission. This necessitates the development of well-organized TB control programs (responsive and adaptable to the reforming health sector). TB is responsible for considerable direct and indirect costs to the individuals and the society. The economic dimension of TB control relates to a reduction of these costs, alleviation of poverty, and promotion of development.(1) The emergence of resistance to drugs used to treat TB, and particularly multi-drug-resistant TB (MDR TB), has become a significant public health problem and an obstacle to effective TB control.(2) Drug resistance is manifested when there is a selective growth of resistant mutants among the actively multiplying bacillary population in the presence of drugs. The emergence of drug resistance depends upon the frequency of drug resistant mutants in the susceptible bacillary population, the size of the actively multiplying bacillary population in the lesions, and the anti-microbial quality of the drugs used. Drug resistance of the Mycobacterium tuberculosis isolated from patients who have been treated for 1 month or more is defined as “acquired drug resistance”, while that of patients who have never been treated previously or treated for less than 1 month is called “primary drug resistance”.(3) Resistance to a single drug is defined as “mono resistance” and resistance to two or more drugs is defined as “poly resistance.” Resistance to at least Isoniazid and Rifampicin is termed as “MDR”.