GLOBAL SURVEILLANCE FOR ANTITUBERCULOSIS-DRUG RESISTANCE, 1994-1997

Background Drug-resistant tuberculosis threatens efforts to control th e disease. This report describes the prevalence of resistance to four first-line drugs in 35 countries participating in the World Health Org anization-lnternational Union against Tuberculosis and Lung Disease Gl obal Project on Anti-Tuberculosis Drug Resistance Surveillance between 1994 and 1997. Methods The data are from cross-sectional surveys and surveillance reports. Participating countries followed guidelines to e nsure the use of representative samples, accurate histories of treatme nt, standardized laboratory methods, and common definitions. A network of reference laboratories provided quality assurance. The median numb er of patients studied in each country or region was 555 (range, 59 to 14,344). Results Among patients with no prior treatment, a median of 9.9 percent of Mycobacterium tuberculosis strains were resistant to at least one drug (range, 2 to 41 percent); resistance to isoniazid (7.3 percent) or streptomycin (6.5 percent) was more common than resistanc e to rifampin (1.8 percent) or ethambutol (1.0 percent). The prevalenc e of primary multidrug resistance was 1.4 percent (range, 0 to 14.4 pe rcent). Among patients with histories of treatment for one month or le ss, the prevalence of resistance to any of the four drugs was 36.0 per cent (range, 5.3 to 100 percent), and the prevalence of multidrug resi stance was 13 percent (range, 0 to 54 percent). The overall prevalence s were 12.6 percent for single-drug resistance (range, 2.3 to 42.4 per cent) and 2.2 percent for multidrug resistance (range, 0 to 22.1 perce nt). Particularly high prevalences of multidrug resistance were found in the former Soviet Union, Asia, the Dominican Republic, and Argentin a. Conclusions Resistance to antituberculosis drugs was found in all 3 5 countries and regions surveyed, suggesting that it is a global probl em. (C) 1998, Massachusetts Medical Society.