Postantibiotic effects of norfloxacin and enrofloxacin on some pathogenic bacteria from aquatic animals

From the determination of minimal inhibitory concentrations (MIC) of norfloxacin against Vibrio alginolyticus s622 and enrofloxacin against Edwardsiella tarda 751 by twofold macrodilution in broth, and the determination of postantibiotic effects(PAE) of norfloxacin against Vibrio alginolyticus s622 and enrofloxacin against Edwardsiella tarda 751 by colony counting, the results showed that the PAE of norfloxacin against Vibrio alginolyticus at the concentration of 1/2MIC, 1MIC, 2MIC and 4MIC was 0.47h, 0.76h, 1.26h and 2.05h, respectively; and the PAE of enrofloxacin against Edwardsiella tarda was 0.29h,0.48h,1.97h and 2.30h, respectively. It showed that postantibiotic effects induced by norfloxacin and enrofloxacin were obvious. It can be pointed out that when preparing a prescription, we can prolong the medicine-administered interval time and reduce the number of times of administration, and the antibiotic effect can still maintain.