Abstract

This study was done to evaluate in vitro susceptibility of Mycobacterium tuberculosis of clarithromycin. In this prospective study, 90 M. tuberculosis strains (40 resistant strains and 50 susceptible strains) referred to the Tabriz laboratory of TB research Center were selected and cultured in L-J medium and with 3 doses of clarithromycin. 40 strains were resistant and 50 strains were sensitive to first line drugs. 60% of strains were resistant to clarithromycin with 20 µg/ml. Significant difference was not found if resistant rate of M. tuberculosis strains to clarithromycin with 20 and 40 µg/ml and all studied strain was sensitive to clarithromycin with 80 µg/ml. 33 strains of resistant strains and 48 strains of sensitive strains to first anti tuberculosis line drug was sensitive to clarithromycin with 40 µg/ml. Based on the results of this study and other studies, the need for extensive laboratory study and using liquid culture (including Midelbary) and advanced techniques such as BACTEC and even more animal models are necessary. The long-term clinical study using clarithromycin in combination with anti-TB therapy, especially in the case of MDR-TB strains is necessary for the low side effect as clarithromycin in the treatment of tuberculosis, in the form of suitable compounds which can be used as second drug.

Key words: Mycobacterium tuberculosis, drug resistant, clarithromycin, strains.