| This work was aimed to investigate the drug tolerance to E.coli in a large scale layer farm. 20 samples were collected from
chicks, pullets in 5~12 weeks old and layers, all of which died of disease, in a large scale layer-raising farm around Nanning, Guangxi province. The samples were dealt with isolation and identification of Pathogenic Bacteria, Pathogenic Test and Serotype identification, and 18 strains collected from them were mainly blood-grouped serologically as O50, O133, O88, O8, O78. The drug sensitivity testing to E.coli of 25 drugs was done by Kirby-Bauer method. The results showed that 80% of the separated strains had a high sensitivity to meropenem,imipenem and cefotaxime while they showed various degrees of drug tolerance to 23 Ampicillin, Oxacillin, Spectinomyc, Tetracycline and chloramphenicol. And 100% of the separated strains showed drug tolerance to polymyxin B, cotrimoxazole and streptomycin. It suggested that the drug tolerance to E-coli in the layer–raising farm was very serious. |
