Comparative in-vitro activity of five fluoroquinolones against mycobacteria

Fifty distinct strains of mycobacteria were investigated to determine their in-vitro susceptibility to five new fluoroquinolones (norfloxacin, pefloxacin, ofloxacin, enoxacin and ciprofloxacin). Ofloxacin and ciprofloxacin were found to be the most active, with minimum inhibitory concentrations (MIC) of 1.25 mg/l or less to all strains of Mycobacterium tuberculosis, M. bovis, M. xenopi, M. kansasii and BCG tested. All agents showed little activity against M. malmoense and M. avium-intracellulare complex with MIC values of greater than 2.5 mg/l.