African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5124

Full Length Research Paper

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

Reshma Bellad
  • Reshma Bellad
  • Department of Microbiology, JNMC, KAHER Nehru Nagar, Belgavai-590010, Karnataka, India.
  • Google Scholar
Mahantesh Nagamoti
  • Mahantesh Nagamoti
  • Department of Microbiology, JNMC, KAHER Nehru Nagar, Belgavai-590010, Karnataka, India.
  • Google Scholar

  •  Received: 23 July 2019
  •  Accepted: 13 July 2020
  •  Published: 31 July 2021


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. 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. 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 using various biochemical tests. DST was carried against the first line of anti-TB drugs. MTB positive samples were subjected to LPA. 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. LPA revealed 54 MTB positive among 57 MTB culture-positive samples and 3 showed invalid results. In LPA, MDR-TB was found in10 samples (17.54%) in which one was RIF-resistant. The study 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.

Key words: Tuberculosis (TB), multidrug resistance (MDR-TB), drug susceptibility testing (DST), line probe assay (LPA).