The MTB/MDR ELITe MGB^® Kit: Performance Assessment for Pulmonary, Extra-Pulmonary, and Resistant Tuberculosis Diagnosis, and Integration in the Laboratory Workflow of a French Center

• Main Authors: Elisabeth Hodille, Charlotte Genestet, Thomas Delque, Luna Ruffel, Yvonne Benito, Isabelle Fredenucci, Jean-Philippe Rasigade, Gérard Lina, Oana Dumitrescu
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Pathogens
• Subjects: tuberculosis diagnosis; <i>Mycobacterium tuberculosis</i> complex; Nucleic acid amplification test; MTB/MDR ELITe MGB^® Kit; multidrug-resistant tuberculosis
• Online Access: https://www.mdpi.com/2076-0817/10/2/176

A rapid and reliable diagnostic for tuberculosis, including the detection of both rifampicin (RIF) and isoniazid (INH) resistance, is essential for appropriate patient care. Nucleic acid amplification tests are a fast alternative to methods based on <i>Mycobacterium tuberculosis</i> complex (MTB) cultures. Thus, the performance of the MDR/MTB ELITe MGB^® Kit on the ELITe InGenius^® platform was retrospectively evaluated for MTB detection on pulmonary and extra-pulmonary samples and for RIF/INH resistance detection on MTB strains. The sensitivity and specificity of the kit for MTB detection compared to the MTB culture were 80.0% and 100.0%, respectively. For the antimicrobial susceptibility prediction, the agreement with phenotypic antimicrobial susceptibility testing (AST) was 92.0%. For RIF, the sensitivity was 100.0% and the specificity was 95.5%. For INH, the sensitivity and specificity were 75.0% and 100.0%, respectively. A single RIF false-positive result was obtained for a strain with a low level of RIF resistance that was not detected by phenotypic AST, but carrying a <i>rpoB</i> L452P mutation. INH false-negative results (3) were due to mutations on the <i>katG</i> gene that were not probed by the test. Overall, the MTB/MDR ELITe MGB^® Kit presents a strong performance for MTB detection and for the detection of both RIF and INH resistance, with an easy integration in laboratory workflow thanks to its fully automatized system.