Tuberculosis in Korea. The relationship between prior therapy and drug resistance.

A review of 121 culture-positive cases of pulmonary tuberculosis from 1979 to 1984, including both Korean and American patients, at the major US military hospital in Korea indicated that most antituberculosis drug resistance occurred in patients with a history of previous antituberculosis therapy. The 98 patients without previous therapy who were not household contacts of a known resistant case had low rates of drug resistance (7 percent to isoniazid, 5 percent to streptomycin, 2 percent to p-aminosalicylic acid, and none to rifampin or ethambutol). All were sensitive to at least two of the drugs in the commonly prescribed regimen of isoniazid, rifampin, and ethambutol. In contrast, both patients who were household contacts of a known resistant case and 11 (52 percent) of the 21 patients with previous therapy had drug-resistant organisms. Our data support the use of isoniazid as preventive therapy for those who develop tuberculin reactivity while in Korea, in the absence of close contact with a known resistant case. Our data also suggest that the regimen of isoniazid, rifampin, and ethambutol is appropriate initial therapy for active disease acquired in Korea, provided that an adequate history excluding these risk factors can be obtained.