Mycobacterium tuberculosis resistance in pulmonary TB patients in Cameroon: a phenotypic susceptibility assay.

Abstract

To determine the resistance of Mycobacterium tuberculosis to first- and second-line agents in adult pulmonary tuberculosis (TB) patients in Cameroon using a novel phenotypic assay. Samples were collected from TB patients at Bamenda Hospital in Bamenda, Cameroon. Samples were collected consecutively from adult pulmonary TB patients over a 2-month period. TREK Sensititre(TM) MYCOTB panels were used to perform phenotypic drug susceptibility testing (DST). Susceptibility/resistance was determined by comparing minimum inhibitory concentrations to standard critical concentrations established for first- and second-line anti-tuberculosis drugs. Of 103 sputum samples processed, growth on Löwenstein-Jensen media was confirmed in 78 samples, 65 of which were suitable for DST. Thirty-nine strains (60%) were susceptible to all first- and second-line drugs. Five strains (8%) were categorized as multidrug-resistant TB. Two strains (3%) were classified as pre-extensively drug-resistant TB. Of those isolates susceptible to first-line drugs, 20% were resistant to at least one second-line drug. Antimicrobial resistance may be higher than assumed in TB strains in Cameroon, especially with regard to second-line drugs. There remains a need for rapid, comprehensive DST.