Abstract: Etiological diagnosis were done to the dead broiler from one farm which experienced the epidemic in this experiment. The isolated bacteria were identified by methods of pathogenic separation, biochemical tests, animal experiments, serotype identification, PCR amplification and so on. As a result, the mixed infections of E.coli and Enterococcus faecalis were identified. Further more, drug susceptibility tests were taken according to the isolated bacteria and the high sensitivity antibiotics against E.coli named amikacin and gentamycin were selected, while only some fluoroquinolones showed moderately sensitive against Enterococcus faecalis among the 21 antibiotics. Then amikacin, gentamycin and enrofloxacin were used for the treatment of broiler, which showed quick effects on controlling the death, and greatly reduced the economic losses caused by the epidemic.

Key words: broiler; E.coli; Enterococcus faecalis; PCR; drug susceptibility test