Drug-Resistant Tuberculosis

Abstract

Eastern Europe, Henan province in China, and certain parts of Russia. 1 The resistance to single drug was reported to range from 2 to 41% (median 9.9%) and to multiple drugs was 0 to 14.4% (prevalence 1.4%) in those who never received prior treatment. Single-drug resistance varied from 2.3 to 42.4% and multi-drug resistance ranged between 0 and 22.1% among those who had prior treatment for tuberculosis. 2 Recently, data from several countries show an average overall incidence of MDR-TB to be 3.4% with highest from Estonia at 14%, Henan Province at 11%, and Latvia and Ivanovo at 9%. 3 The emergence of multi-drug resistance across the world poses a global threat as the treatment is difficult, expensive, and a major health care cost burden to developing countries. Mortality rate in MDR-TB varied from 12% in non-human immunodeficiency virus (HIV) infection to 90% among HIV infected. 4 Historically, Mycobacterium tuberculosis has been difficult to treat. Early reports of effective therapy against active tuberculosis showed that M. tuberculosis quickly developed resistance to drug therapy. 5 Drugresistant tuberculosis (TB) is M. tuberculosis that is resistant to at least one first-line anti-TB drug. MDR-TB is defined as M. tuberculosis resistant to more than one anti-TB drugs (and at least isoniazid (INH) and rifampin (RIF)). Several factors have led to the increase in MDR-TB: inappropriate prescribing practices, noncompliance with prescriptions, and increase in the transmission of MDR-TB. In the late 1940s and early 1950s, treatment regimes for M. tuberculosis and success rates were published 5-8 Drugs used included Streptomycin and para-aminosalicylic acid. The early reports showed that monodrug