Background and objectives: Investigation and study of second-line drugs effects on mycobacterial strains has been of great importance due to prevalence of drug resistance especially multi-drug resistance (MDR) in Mycobacterium tuberculosis (MTB) strains in the recent years. The objective of this research was to determine drug sensitivity of Mycobacterium tuberculosis and mycobacteria other than tubercle bacilli (MOTT) strains to the two common second-line anti-mycobacterial fluoroquinolones, i.e. ofloxacin (OFL) and ciprofloxacin (CIP).
Materials and methods: In this study, the in-vitro activities of two drugs of OFL and CIP, considering the effects of first-line drugs (isoniazid, rifampin, streptomycin and ethambutol) were studied on 100 mycobacterial strains containing 90 MTB and 10 MOTT strains isolated from patients admitted to research center for TB and pulmonary diseases of Tabriz, Iran, by proportion method of drug susceptibility on Lowenstein-Jensen (LJ) medium.
Results and conclusion: Out of 90 MTB strains, 50 strains that were sensitive to the first line drugs were diagnosed as susceptible to OFL and CIP. Of other 40 strains which were resistant to the first line drugs, only one strain was resistant to OFL and 2 strains were found to be resistant to CIP. Of 10 MOTT strains, 4 strains were resistant to OFL and 3 strains were found to be resistant to CIP. The findings of this investigation revealed that OFL and CIP could be effectively used against MTB and MOTT.