African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5044

Article in Press

Molecular diagnosis of Multidrug-resistant Tuberculosis from culture-positive isolates using line probe assay in North Karnataka

Reshma Bellad, Mahantesh Nagamoti

  •  Received: 23 July 2019
  •  Accepted: 13 July 2020
Background: The control of tuberculosis (TB) has become a global health challenge due to the emergence of multidrug-resistant tuberculosis (MDR-TB) in Mycobacterium tuberculosis (MTB). This highlights the need for faster and more accurate detection of tuberculosis cases. Objectives: The study aims to detect MDR-TB strains of pulmonary tuberculosis using resistance ratio method and to compare the diagnostic value of drug susceptibility testing (DST) with line probe assay (LPA) using Genotype MTBDRplus assay for the detection of resistance to rifampicin (RIF) and isoniazid (INH) in culture-positive isolates. Methods: All the sputum samples were tested for Acid Fast Bacilli (AFB) by Ziehl-Neelsen’s staining method and were cultured on Lowenstein-Jensen (L-J) media. The identification and confirmation of M. tuberculosis were done by using various biochemical tests. DST was carried against the first line of anti-TB drugs: (Isoniazid-INH, Rifampicin-RFP, Streptomycin-SM, and Ethambutol-EMB. MTB positive samples were subjected to LPA, to compare the performance of identifying MDR-TB. Results: A total of 57 samples were subjected to DST and LPA for the detection of drug resistance of MTB to RIF and INH after conventional detection methods were applied to all the samples. Among these 57 MTB samples, 11 (19.29%) were resistant to INH, 4 (7.14%) were resistant to RIF; eleven (19.29%) isolates were identified as MDR-TB through the resistance ratio method of DST. LPA revealed 54 MTB positive among 57 MTB culture-positive samples and 3 showed invalid results. The tuberculosis-complex DNA band TUB was absent in all the five NTM specimens. In LPA, MDR-TB was found in10 samples (17.54%) in which one was RIF-resistant. Conclusion: The present study concludes that the proper determination of drug resistance by the proper method is helpful to minimize the spread of drug-resistant TB. The study also concludes risk factors that resulted in the development of TB are biomedical, socio-cultural, and behavioral interactions. LPA can be used as a rapid diagnostic technique for the detection of MDR-TB.

Keywords: Tuberculosis (TB), Multidrug resistance (MDR-TB), Drug susceptibility testing (DST), Line probe assay (LPA).