Resazurin microtitre plate assay and Sensititre® MycoTB for detection of Mycobacterium tuberculosis resistance in a high tuberculosis resistance setting

Prenika Jaglal; Melendhran Pillay; Koleka Mlisana

doi:10.4102/ajlm.v8i1.840

Resazurin microtitre plate assay and Sensititre® MycoTB for detection of Mycobacterium tuberculosis resistance in a high tuberculosis resistance setting

Afr J Lab Med. 2019 Dec 13;8(1):840. doi: 10.4102/ajlm.v8i1.840. eCollection 2019.

Authors

Prenika Jaglal¹, Melendhran Pillay², Koleka Mlisana¹

Affiliations

¹ Department of Medical Microbiology, National Health Laboratory Services, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban, South Africa.
² Department of Medical Microbiology/Virology, National Health Laboratory Service, Durban, South Africa.

Abstract

Background: Rapid diagnosis of drug-resistant Mycobacterium tuberculosis is a challenge in low-income countries. Phenotypic drug susceptibility testing using Sensititre^® MycoTB assay and the resazurin microtitre plate assay (REMA) are relatively new innovative methods to determine drug susceptibility.

Objectives: This study aimed to determine the performance of the Sensititre and REMA for M. tuberculosis drug susceptibility testing in a high-volume tuberculosis reference laboratory.

Methods: A laboratory-based study was performed at the Inkosi Albert Luthuli Central Hospital Tuberculosis Laboratory from January 2014 to June 2015. The Sensititre^® MycoTB plate and REMA were compared to the gold standard agar proportion method (APM) using 134 stored isolates.

Results: Agreement between the Sensititre^® MycoTB plate and APM was observed with 98% sensitivity, 82% specificity, 94% positive and 93% negative predictive values of the Sensititre^® MycoTB assay for the detection of rifampicin resistance and 97%, 96%, 99% and 88% for isoniazid resistance. Good categorical agreement between the REMA and the APM was observed among isolates with 89% sensitivity, 68% specificity, 89% positive and 68% negative predictive value for the detection of rifampicin resistance and 95%, 96%, 99% and 81% for isoniazid resistance. Results for the second-line drugs showed elevated minimum inhibitory concentrations for multidrug-resistant and extensively drug-resistant tuberculosis isolates.

Conclusion: The REMA and Sensititre^® MycoTB plate are attractive alternatives to the gold standard APM for the phenotypic detection of M. tuberculosis drug resistance.

Keywords: Mycobacterium tuberculosis; Sensititre® MycoTB assay; agar proportion method; extensively drug-resistant tuberculosis; multidrug-resistant tuberculosis; resazurin microtitre plate assay.