Evaluation of the frequency of resistance to 2 drugs (Isoniazid and Rifampin) by molecular investigation and it's risk factors in new cases of smear positive pulmonary tuberculosis in health centers under the cover of Jundishapur University of Medical Sciences in 2017

INTRODUCTION: Despite the great efforts to control tuberculosis (TB), the disease is still one of the major health challenges throughout the world. The basic treatment for TB is drug therapy. Currently, the main anti-tuberculosis drugs with major use in the treatment and control of the disease are isoniazid, rifampin, pyrazinamide, ethambutol, and streptomycin. One of the serious crises in controlling TB epidemic is diagnosis and treatment of patients with Multidrug Resistant Tuberculosis (MDR-TB MDR). The purpose of the study was to examine and evaluate the resistance of mycobacterium TB strains isolated from specimens of newly diagnosed smear positive pulmonary TB to isoniazid and rifampin using molecular methods and their risk factors. METHODS: Sputum samples of newly diagnosed smear positive pulmonary TB patients were prepared, collected, and sent to Reference Laboratory in Ahvaz. DNA of mycobacterium tuberculosis was prepared from the samples using Qiagen kit according to the instructions of the manufacturing company. Isoniazid resistance was evaluated using specific primers for inhA and KatG genes. Rifampin resistance was evaluated using MAS-PCR method with three specific alleles of rpobB codons and codons 516, 526 and 531. RESULTS: Mycobacterium tuberculosis resistance to Isoniazid was 7.3%, to Rifampin 5.5% and to both drugs 1.8%. In our study, there were no association between drug resistance and gender, age, prison history, smoking, drug use, underlying disease, occupation, and HIV. CONCLUSION: According our findings that include prevalence of 7.3% Isoniazide resistance, 5.5% Rifampin resistance and 1.8% to both drugs, evaluating all newly diagnosed patients for resistance to standard anti-tuberculosis treatment seems rational.