Initial resistance to antituberculosis drugs in Yaounde, Cameroon in 1995

Tuberculosis centre of Hôpital Jamot, Yaounde, Cameroon, the sole referral and tuberculosis treatment facility for Yaounde and its surroundings.

To identify Mycobacterium tuberculosis complex strains responsible for pulmonary tuberculosis in Yaounde, determine the prevalence of initial resistance to the main antituberculosis drugs and compare this prevalence in human immunodeficiency virus (HIV) positive and HIV-negative patients.

In total, 576 consecutive and previously untreated adult patients admitted with sputum smear positive pulmonary tuberculosis to the tuberculosis centre from July 1994 to December 1995 were included in the study. Sputum specimens collected from each eligible patient were cultured on Löwenstein-Jensen and Coletsos media. Identification of the cultured strains was based on their cultural aspects and standard biochemical tests. The susceptibility of isolates to the major antituberculosis drugs was tested using the indirect proportion method. HIV testing was done using two ELISAs and confirmed by Western blot.

Growth of M. tuberculosis complex strains was obtained from specimens of 516 (89.6%) of the 576 patients: 53 (10.3%) were identified as M. africanum and 463 (89.7%) as M. tuberculosis. Of the 516 patients with culture positive specimens, 92 (17.8%) were HIV-positive. Of the 516 strains isolated, 164 (31.8%) were resistant to at least one drug. The pattern of resistance was noted as 25% to one drug, 5.8% to two drugs and 1% to three or more drugs. Initial resistance to streptomycine was the most frequent (20.5%), followed by isoniazid (12.4%), thiacetazone (5.6%), rifampicin (0.8%) and ethambutol (0.4%). No significant difference in the rate of initial resistance was observed between HIV-positive and HIV-negative patients.

The rate of initial drug resistance of M. tuberculosis in Yaounde is relatively high. There is therefore an urgent need to reestablish a tuberculosis control programme in Cameroon.