Multicenter Study of the Accuracy of the BD MAX Multidrug-resistant Tuberculosis Assay for Detection of Mycobacterium tuberculosis Complex and Mutations Associated With Resistance to Rifampin and Isoniazid

BACKGROUND: Tuberculosis (TB) control is hindered by absence of rapid tests to identify Mycobacterium tuberculosis (MTB), and detect isoniazid (INH) and rifampin (RIF) resistance. We evaluated the accuracy of the BD MAX MDR-TB assay (BD MAX) in South Africa, Uganda, India, and Peru. METHODS: Outpatient adults with signs and/or symptoms of pulmonary TB were prospectively enrolled. Sputum smear-microscopy and BD MAX were performed on a single raw sputum, which was then processed for mycobacterial culture and phenotypic drug susceptibility testing (DST), BD MAX and Xpert MTB/RIF (Xpert). RESULTS: 1053 participants with presumptive TB were enrolled with median age of 35 (47% female; 32% HIV-infected, and 32% unknown HIV status). In microbiologically-confirmed TB patients, BD MAX sensitivity was 93% (262/282 [95% CI 89, 95]); specificity was 97% (593/610 [96, 98]) among participants with negative cultures on raw sputa. BD MAX sensitivity was 100% (175/175, [98,100]) for smear-positive samples (florescence smear-microscopy), and 81% (87/107, [73,88]) in smear-negative samples. Among participants with both BD MAX and Xpert, sensitivity was 91% (249/274, [87,94]) for BD MAX and 90% (246/274 [86,93]) for Xpert on processed sputa. Sensitivity and specificity for RIF resistance compared to phenotypic DST was 90% (9/10 [60,98]) and 95% (211/222 [91,97]), respectively. Sensitivity and specificity for detection of INH resistance was 82% (22/27 [63,92]) and 100% (205/205 [98,100]), respectively. CONCLUSIONS: The BD MAX MDR-TB assay had high sensitivity and specificity for detection of MTB, and RIF and INH drug resistance and may be an important tool for rapid detection of TB and MDR-TB globally.