Drug susceptibilities and clinical manifestations of Mycobacterium Tuberculosis in Zambia.

The inappropriate use of anti-tuberculosis drugs has resulted in an increase in the drug resistance. This study was conducted to obtain data related to the spectrum of drug resistant Mycobacterium tuberculosis. A total of 499 strains ofM. tuberculosis were tested for susceptibilities of isoniazid (INH), rifampicin (RFP), ethambutol (EMB) and streptomycin (SM). Totally 225 patients were also evaluated for their clinical manifestations. The primary and acquired resistances were observed in 13.9% and 16.1% to INH, 11.1% and 12.9% to RFP, 6.7% and 9.7% to EMB, and 3.8% and 3.2% to SM respectively. There were no significant differences between primary and acquired resistances. Multi-drug resistance was observed in 22 strains (4.4%). Clinical manifestation, as measured by chest roentgenograms, was similar in patients with either drug-susceptible or resistant strains. The clinical and radiological information was not useful for the prediction of susceptible and resistant strains. The HIV serostatus was not associated with drug susceptibility profiles either. Our study has documented a high incidence of drug resistant M. tuberculosis, with no obvious clinical correlates, which must be considered when implementing a strategy for chemotherapy. As for clinical practices, many defaults during chemotherapy reduced the treatment successes. It is important to assess the efficient implementation of the directly observed treatment with short course chemotherapy (DOTS) and interrupt the further dissemination of resistant M. tuberculosis in the community. The drug resistances must be surveyed continuously to obtain useful clinical perspective and evaluate the effectiveness of tuberculosis control program.