DRUG-RESISTANT TUBERCULOSIS

Multidrug-resistant tuberculosis (MDRTB) is an iatrogenic disease that is emerging as a major infectious disease problem throughout the world. The AIDS pandemic, increased incidence of tuberculosis in populations with easy access to antituberculosis medications, the deterioration of the public health infrastructure, and inadequate training of health care providers in the epidemiology of tuberculosis are some of the factors contributing to the increased incidence of MDRTB. Mortality from MDRTB exceeds 80% in persons infected with human immunodeficiency virus (HIV) but is also high in patients free of HIV. The management of MDRTB is complicated by the lack of methods for rapid detection of resistant strains of Mycobacterium tuberculosis. The risk of infection among close contacts of patients with MDRTB, the probability of the development of active MDRTB after infection, and the likelihood of cure of MDRTB need to be determined quantitatively. Attributable risk estimates for factors associated with MDRTB should be calculated for each community as part of the strategies to prevent MDRTB. Issues regarding chemoprophylaxis in newly infected contacts of MDRTB cases remain unanswered. Basic research on the mechanisms of action of existing antituberculosis drugs may contribute to an understanding of the mechanism of resistance in M. tuberculosis. There is an urgent need to expand the scope of epidemiological, clinical, and laboratory research to address these problems.