Mycobacterium tuberculosis complex strains and drug susceptibility in a cattle-rearing region of Cameroon.

SETTING

Seven district hospitals in the Adamaoua Region of Cameroon, June 2009 to May 2010.

OBJECTIVES

To identify species among Mycobacterium tuberculosis complex (MTC) strains responsible for pulmonary tuberculosis (PTB) and determine their susceptibility to anti-tuberculosis drugs.

DESIGN

Sputum specimens were collected from 509 consecutively admitted adults and cultured. Identification of cultured strains was mainly based on culture growth characteristics and standard biochemical tests with spoligotyping for confirmation on a subset of strains. Drug susceptibility testing was performed using the indirect proportion method.

RESULTS

Growth of MTC strains occurred in specimens of 445/509 (87.4%) patients: 433 (97.3%) were identified as M. tuberculosis, 10 (2.3%) as M. africanum and 2 (0.4%) as M. bovis. The overall resistance rate was 7.9%, with 7.3% resistance in new cases and 21.1% in previously treated cases. Isoniazid resistance in new cases was most common (4.2%), followed by streptomycin (3.3%), rifampicin (1.9%) and ethambutol (0.9%). Multidrug-resistant tuberculosis was more frequent in previously treated than in new cases (10.5% vs. 1.4%, P < 0.05).

CONCLUSION

Although the Adamaoua Region is a stock-farming area, M. tuberculosis is the predominant MTC species responsible for PTB. Anti-tuberculosis drug resistance in new and previously treated cases is well established, underscoring the need to reinforce the DOTS strategy.