In vitro Drugs Susceptibility Test for Chicken Escherichia coli Isolated in North of Henan Province

The sensitivity effects for 17 antibacterial medicines on 15 strains chicken E.coli were studied according to broth microdilution method.The results showed that polymycin B had strong antibacterial activities against chicken E.coli in vitro.The MIC50 was 0.11 μg/mL,the MIC90 was 0.87 μg/mL.Gatifloxacin was poor active against chicken E.coli The MIC50 and MIC90 was 2.53 μg/mL,3.88 μg/mL.The antibacterial activities of those 3 quinolones in vitro were similar but somewhat weaker than gatifloxacin.The 3 quinolones MIC50 and MIC90 were 10.11~11.79 μg/mL,15.16~21.13 μg/mL,respectively.The other 12 antibacterial drugs showed weak power on E.coli,whose MIC50 and MIC90 were 18.53~388.50 μg/mL,30.59~713.42 μg/mL.