MTB/MDR ELITe MGB kit performance assessment on patient samples and Mycobacterium tuberculosis clinical isolates characterized by whole genome sequencing. MTB/MDR ELITe MGB kit: performance assessment

A rapid and reliable diagnostic for tuberculosis, including the detection of rifampicin (RIF) and/or isoniazid (INH) resistance, is essential for appropriate patient care. Nucleic acid amplification tests are a fast alternative to methods based on Mycobacterium tuberculosis complex (MTB) culture. Herein, the performance of the MDR/MTB ELITe MGB® kit on the ELITe InGenius® platform were retrospectively evaluated for MTB detection on pulmonary and extra-pulmonary samples and for RIF/INH-resistance detection on MTB strains. For antimicrobial susceptibility prediction, the agreement with phenotypic antimicrobial susceptibility testing (AST) and with resistance prediction from whole genome sequencing (WGS) was calculated. For RIF, the sensitivity was 100.0% and the specificity was 95.5% versus AST. A single RIF false-positive result was obtained for a strain with a low-level of RIF resistance not detected by phenotypic AST, but displaying a rpoB L452P mutation in WGS. INH false-negative results (3) were due to mutations on katG gene detected by WGS but not probed by the test.