African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5210

Full Length Research Paper

Isoniazid resistance of Mycobacterium tuberculosis isolated from human patients

Taha Nazir1*, Abdul Hameed2, Javed Anver Qureshik3 and Bashir Ahmad4
  1Riphah Institute of Pharmaceutical Sciences, Riphah International University 7th Avenue G/7-4, Islamabad, Pakistan. 2Department of Microbiology, Quaid-I-Azam University, Islamabad, Pakistan. 3National Institute of Biotechnology and Genetic Engineering, Faisalabad, Pakistan. 4School of Pharmacy, University of the Punjab, Lahore, Pakistan.
Email: [email protected] or [email protected]

  •  Accepted: 30 July 2011
  •  Published: 09 November 2011



Isoniazid resistant Mycobacterium tuberculosis strains are a serious threat for successful tuberculosis control programs. Therefore, present study was aimed to figure out the pattern and level of resistance of M. tuberculosis against isoniazid. A total of 172 specimens of sputum, pus and bronchial washings; 70.9% males and 29.1% females with 84.30% pulmonary and 15.69% extrapulmonary tuberculosis were collected from six different sources. The inoculums were prepared using 0.5 Mac Farland turbidity standards. Five concentrations of isoniazid were used in Lowenstein Jensen (LJ) medium that is 3, 6, 9, 12 and + 12 μg/ml for sensitivity testing. Data showed 25 (14.5%) resistant and 147 (85.5%) sensitive M. tuberculosis strainsThe growth was not inhibited at first (3 μg/ml) and second (6 μg/ml) drug levels, while 36% isolates inhibited at third level (9 μg/ml), 28% at forth level (12 μg/ml) and 24% at fifth level (10 μg/ml) and 12% at higher than fifth Level (> 12 ug/ml). These incorporated drug concentrations are higher than therapeutic index and not recommended in actual clinical practice. It is thus obvious to explore some other effective chemotherapeutic agents, modify combinations or figure out more effective procedures to stop morbidity and mortality due to isoniazide resistance ofM. tuberculosis.


Key words: Isoniazid, mycobacterium tuberculosis, resistance, Lowenstein Jensen medium.