MTBDRplus and MTBDRsl for simultaneous diagnosis of gastrointestinal tuberculosis and detection of first-line and second-line drug resistance.

BACKGROUND: Emergence of drug resistance, especially to second-line drugs, hampers tuberculosis elimination efforts. The present study evaluated MTBDRplus and MTBDRsl assays for detecting first-line and second-line drug resistance, respectively in gastrointestinal tuberculosis (GITB).

METHODS: 30 ileo-caecal biopsy specimens, processed in the Department of Microbiology between 2012-2022, that showed growth of M. tuberculosis on culture were included in the study. DNA, extracted from culture, was subjected to MTBDRplus and MTBDRsl (Hain Lifescience, GmbH, Nehren, Germany), following manufacturer's instructions. Their performance was compared against phenotypic drug susceptibility testing (pDST) and gene sequencing.

RESULTS: Out of 30 specimens, 4 (13.33%) were mono-isoniazid resistant, 4 (13.33%) were multidrug resistant, 2 (6.67%) were pre-XDR and 2 (6.67%) had mono-fluoroquinolone resistance. The results were 100% concordant with pDST and gene sequencing.

CONCLUSIONS: In the wake of growing drug resistance in all forms of extra-pulmonary tuberculosis, including GITB, MTBDRplus and MTBDRsl are reliable tools for screening of resistance to both first-line and second-line drugs.