Evaluation of GenoType® MTBDRplus for the rapid detection of drug-resistant tuberculosis in Ghana

• Published in: The international journal of tuberculosis and lung disease 2015-08, Vol.19 (8), p.954-959
• Main Authors: Asante-Poku, A., Otchere, I. D., Danso, E., Mensah, D. D., Bonsu, F., Gagneux, S., Yeboah-Manu, D.
• Format: Article
• Language: English
• Subjects: Antitubercular Agents - pharmacology; Cross-Sectional Studies; Drug Resistance; Drug Resistance, Multiple, Bacterial; Ghana; Humans; Isoniazid - pharmacology; Line-Probe Assay; Microbial Sensitivity Tests; Molecular Diagnostic Techniques - methods; Mutation; Mutations; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - isolation & purification; Phenotype; Rifampin - pharmacology; Sensitivity and Specificity; Tuberculosis, Multidrug-Resistant - diagnosis; Tuberculosis, Multidrug-Resistant - microbiology; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - microbiology
• ISSN: 1027-3719; 1815-7920
• DOI: 10.5588/ijtld.14.0864

BACKGROUND: Rapid but simple diagnostic tools for the detection of drug-resistant (DR) tuberculosis (TB) have been acknowledged as being important for its effective management and control.OBJECTIVE: To establish a molecular line-probe assay (GenoType® MTBDRplus) for detecting DR-TB in Ghana.METHOD: We first screened 113 Mycobacterium tuberculosis isolates using the indirect proportion method and MTBDRplus. The rpoB and katG genes and the promoter regions of oxyR-ahpC and inhA were sequenced to identify mutations in isolates found to be resistant on phenotypic drug susceptibility testing and/or MTBDRplus. We then analysed an additional 412 isolates using only MTBDRplus.RESULTS: Respectively 43 (8.2%) and 8 (1.5%) isolates were resistant to isoniazid (INH) and rifampicin (RMP), while 8 (1.5%) were multidrug-resistant. In resistant isolates, mutations in codon 450 of rpoB and codon 315 of katG, conferring resistance to respectively RMP and INH, dominated. We found two RMP-resistant isolates with a S450L substitution, each harbouring an additional mutation at S388L and Q409R. Using phenotypic testing as gold standard, the MTBDRplus assay showed a sensitivity and specificity in the detection of RMP and INH resistance and multidrug resistance of respectively 100% and 100%, 83.3% and 100%, and 100% and 100%.CONCLUSION: The high sensitivity of MTBDRplus makes it a valuable addition to the conventional TB diagnostic algorithm in Ghana.