Tuberculosis in Africans

Abstract

(1) The dynamics of changes in drug resistance in tubercle bacilli were studied in 82 patients kept under observation over a lengthy period (up to 57 months). More than 30 cultures of tubercle bacilli were isolated from each of 18 patients during the trials and studied.

(2) A difference was noted in the rate of establishment of bacterial resistance to three drugs (streptomycin, isoniazid, PAS) used in the treatment of tuberculosis patients. Under out-patient conditions resistance was most quickly acquired to streptomycin. Resistance to isoniazid was established considerably more slowly, while resistance to PAS took the longest to become established.

(3) It was shown that during isoniazid treatment about 20 per cent of cultures isolated from patients after various periods of treatment remained sensitive to isoniazid.

(4) Resistance to isoniazid reached a high level in the first seven months of treatment. There after only slight fluctuations occurred in the mean values for resistance to isoniazid in the bacilli populations.

(5) It was noted that resistance to PAS occurs more frequently when a second course of treatment with that drug is given. Acquired resistance to PAS tends to be maintained for a long time after cessation of treatment.

(6) The acquired resistance to streptomycin is maintained in most patients for a long period after cessation of streptomycin treatment; but in some cases it disappears quickly and completely.

(7) For a long period, a study was maintained on correlations between drug resistance and catalase activity in tubercle bacilli isolated from the same patients. It was shown that catalase activity depends on the degree of isoniazid resistance and the range of drug sensitivity, which change during the treatment.