Evaluation of gene mutations involved in drug resistance in mycobacterium tuberculosis strains derived from tuberculosis patients in mazandaran, iran, 2013.

Drug resistance (especially multiple drug resistance) in Mycobacterium tuberculosis makes global concerns in treatment and control of tuberculosis. Rapid diagnosis of drug resistant strains of the bacteria has vital importance in the prognosis of the disease. The aim of this study was to identify the mutations responsible for drug resistance in Mycobacterium tuberculosis strains derived from patients with tuberculosis using line probe assay (LPA) method which rapidly detect drug resistant strains and respective mutations. Sputum samples from tuberculosis patients were collected and cultured on Lowenstein- Jensen medium, and then the colonies of Mycobacterium tuberculosis from cultures of 54 bacterial positive cases were randomly chosen for DNA extraction. Bacterial DNA was extracted using standard Cetyl Trimethyl Ammonium Bromide (CTAB) method. In order to identify drug resistant strains and related mutations, LPA method was applied. Three subjects out of 54 investigated cases were resistant to quinolone (5.5%), and resistance to kanamycin/ amikacin, streptomycin, rifampin, and isoniazid were observed in 3 (5.5%), 4 (7.4%), 3 (5.5%), and 2 (3.7%) of the Mycobacterium tuberculosis strains, respectively. In the present study, 4 cases (7.4%) were detected to be resistant to more than one drug. Since LPA is a rapid method that simultaneously detects mutations involved in drug resistance, applying this method in the prediction of drug resistance and selecting appropriate treatment in tuberculosis patients is recommended.