In vitro antibacterial activity of new derivatives of pyridonecarboxylic acid, norfloxacin, ofloxacin, enoxacin and ciprofloxacin, against Vibrio cholerae O-1

Abstract

In vitro antibacterial activity of new derivatives of pyridonecarboxylic acid, norfloxacin (NFLX), ofloxacin (OFLX), enoxacin (ENX) and ciprofloxacin (CPFX), against Vibrio cholerae O-1 was investigated. A total of 253 V. cholerae O-1 strains of different geographical origin, including 177 sensitive strains and 76 resistant strains to CP, TC, SM, KM, AP or ST, were submitted to the test for their minimum inhibitory concentrations (MICs) by standard agar dilution method.Growth of all the strains tested was inhibited by NFLX, OFLX, ENX and CPFX at the concentration of 0.2μg/ml or below. The MICs of these antibiotic agents were considerably lower than those of nalidixic acid, chloramphenicol, tetracycline, streptomycin, kanamycin, ampicillin and trimethoprimsulfamethoxazole, and distributed between 0.1 and ≤0.013μg/ml for NFLX and OFLX, 0.2 and 0.025μg/ml for ENX, and 0.025 and ≤0.013μg/ml for CPFX, regardless of serotype, source, year of isolation, or sensitivity to the other antibacterial drugs than these pyridonecarboxylic acid derivatives of test strains.