Abstract: The purpose of this paper is to study biochemical characteristics, drug sensitivity, serotype and pathogenicity of Escherichia coli. The geese from a farm in Jiangsu province had a symptom of dyspnea and high mortality. The autopsy shows air sac inflammation and pulmonary necrosis. One strain was isolated, cultured, stained and tested by microscopy, biochemical identified. The result showed that the isolate was Escherichia coli, agglutination test showed that its serotype was O₂. After microscopic examination of lung nodules tablet, fungal hyphae was no found. 10 sick pigeon and 10 health pigeons were detected respectively for Newcastle disease antibodies, the result demonstrated that the titre was high and uniformity was good and there was no difference between the two antibodies. Sensitive test showed that 7 kinds of drugs such as Florfenicol were sensitive and other 16 drugs such as Cefamezin had drug resistance. The isolated strains were injected 21 days old pigeons, caused 80% mortality. The results show that the isolate has strong pathogenicity.

Key words: geese; Escherichia coli; serotype; drug sensitive test; pathogenicity