The mycobacteriology of pulmonary tuberculosis in South African gold miners

Abstract

Two bacteriological surveys of gold miners with pulmonary tuberculosis diagnosed for the first time, have shown a stable level of primary drug resistance which is substantially lower than that reported for the home areas of these men. Initial drug resistance was detected in 12.7% of the 205 cultures of Mycobacterium tuberculosis in 1983–1984 and in 10.7% of 253 cultures in 1988–1989. Resistance to isoniazid was detected in 5.4% and 5.5% of the strains tested, to streptomycin in 6.8% and 5.1% and to rifampicin in 0% and 0.8% respectively. In a separate study, the sputum bacteriology of 691 miners with relapsed pulmonary tuberculosis was examined. M. tuberculosis was cultured from the sputum of 547 of the men and environmental mycobacteria (EM) in the remainder. Drug resistant tuberculosis was found in 20.5% of the previously treated men: isoniazid resistance in 14.3%, streptomycin resistance in 11.2% and rifampicin resistance in 3.7%. All of the rifampicin resistant strains were also resistant to isoniazid and 85% were resistant to streptomycin as well. Only EM were cultured from 29 of the 234, 1983–1984 sputum cultures, from 23 of the 276, 1988–1989 cultures and from 144 of the 691 relapse cultures. Mycobacterium kansasii (67%) was the commonest EM cultured.