The evaluation of susceptibility of clinical and environmental Nontuberculosis mycobacterium isolated from Isfahan to Ciprofloxacin by Agar dilution method

Introduction: Ciprofloxacin is a fluoroquinolone antibiotic which is active against mycobacteria and functions by inhibiting DNA gyrase and topoisomerase IV enzymes. Resistance to ciprofloxacin and other fluoroquinolones may evolve rapidly, even during a course of treatment. Nowadays, mycobacteria exhibit resistance worldwide and usage of the fluoroquinolones, particularly in nontuberculous mycobacteria disease, has complicated the related treatments. Materials and methods: A total of 39 clinical and environmental isolates of NTM from microbial collections of Isfahan Microbiology Department and Tuberculosis center were obtained. The isolates were investigated by primary conventional methods consisting of colony characteristics, pigmentation, growth temperature, rate of growth and Ziehl–Neelsen staining. The susceptibility of isolates to the concentrations of 1, 2 and 4 µg/ml of ciprofloxacin was determined by agar dilution method according to the CLSI guideline.Results: Thirty nine isolates were identified by phenotypic tests. The frequency of isolates was as follow: M. fortuitum; 25 cases, M. gordonae; 10 cases, M. smegmatis; 1 case, M.‏conceptionense; 1 case and M. abscessus; 2 cases. All isolates except Mycobacterium abscessus were sensitive to all three concentrations of 1, 2 and 4 µg/ml ciprofloxacin.Discussion and conclusion: Due to the sensitivity of environmental nontuberculous mycobacteria isolates (except M. abscessus) and clinical isolates including M. fortuitum and M.‏gordonae to ciprofloxacin, this antibiotic could be regarded as the original drug in the treatment of these infections