Drug-resistant tuberculosis in the 1990s.

There has been an upsurge of tuberculosis in many parts of the world in the past decade. The high rates of drug-resistant tuberculosis currently reported in many countries are alarming. The most catastrophic phenomenon is the emergence of multidrug-resistant strains of Mycobacterium tuberculosis. These organisms have caused epidemic outbreaks in nosocomial and health-care settings in the USA and some European countries. In addition to immigration, poverty, alcoholism and intravenous substance abuse, human immunodeficiency virus (HIV) infection has also had a significant impact on the prevalence of drug resistance, since amongst these patient groups a common factor giving rise to drug resistance is noncompliance. Rapid drug susceptibility tests are needed, and effective chemotherapy regimens with newly developed drugs in combination with traditional second-line antituberculosis agents for established multidrug-resistant tuberculosis are urgently being sought. There is also a quest for other novel modalities of therapy. Measures should be actively adopted to prevent the development of drug resistance. Well formulated short-course chemotherapy as initial treatment and ensurance of compliance are the most important components. The organization of a national tuberculosis control programme with a sound and adequately functioning infrastructure remains the most effective strategy to combat the resurgence of tuberculosis and to curtail drug resistance.