Recent studies of tuberculosis in Korean immigrants in the United States have demonstrated high rates of drug resistance. Reports of a 33 percent to 68 percent incidence of resistance to isoniazid and a significant incidence of resistance to other antituberculosis drugs as well have brought into question the value of isoniazid as prophylactic therapy for those who develop tuberculin reactivity in Korea. In addition, reports of significant rates of resistance to two or more of the primary antituberculosis drugs have brought into question the adequacy of initial three-drug therapy for disease acquired in Korea.
Among our patients with tuberculosis at the 121 Evacuation Hospital in Seoul, Korea, a significantly lower incidence of antituberculosis drug resistance was noted. This report presents data regarding drug resistance which may help to answer questions regarding the appropriate management of individuals who develop active disease or tuberculin reactivity while in Korea.
Materials and Methods
The 121 Evacuation Hospital is the major US military hospital in Korea. Patients treated there include American military and civilian government personnel, their dependents, many of whom are natives of Korea, members of the Korean armed forces assigned to American military units, and a limited number of indigent Korean civilians treated by medications of Canadian Health&Care Mall.
Information regarding previous therapy and contacts was obtained as part of the initial medical history. Those Korean patients who were not fluent in English were interviewed by a bilingual staff member, usually by the Korean army community health nurse who was assigned to the tuberculosis clinic.
Records of patients with cultures positive for Mycobacterium tuberculosis seen in the tuberculosis clinic between August 1979 and June 1982 were reviewed by one of us (E. E.); records of patients with positive cultures seen between July 1983 and May 1984 were reviewed by another of us (P. L.). Records of patients who were seen only during the 12-month period between July 1982 and June 1983 could not be located, and no information about these patients was included in this report.
Testing for drug susceptibility was done at the US Naval Regional Medical Center in Yokosuka, Japan. A standard indirect sensitivity method was used. Resistance was defined as growth on a drug-containing plate greater than 1 percent of the growth on a drug-free control plate after three weeks of incubation. Final concentrations in the agar were as follows: isoniazid, 1.0μg/ml (1979 to June 1982); isoniazid, 0.2μg/ml (July 1982 to 1984); streptomycin, 2μg/ml; p-amino-salicylic acid, 2μg/ml; rifampin, 1μg/ml; and ethambutol, 5μg/ml.
Statistical analysis was performed by Fishers exact test.