鸭源致病性大肠杆菌的分离鉴定及致病性观察

摘要:自湖北省荆州市某鸭场送检病料中分离到一株疑似鸭大肠杆菌,经选择性培养基培养?生化试验?PCR鉴定?动物回归试验?药物敏感性试验,确认为鸭大肠杆菌,该菌对多种抗生素具有耐药性,用已分离鉴定的大肠杆菌经腹腔注射途径感染15日龄雏鸭,致病性试验结果显示,经腹腔注射途径感染雏鸭死亡率达100%,引起纤维素性心包炎?肝被膜炎和气囊炎,说明此株大肠杆菌具有强致病性?

关键词:鸭;大肠杆菌;分离鉴定;致病性

The Identification and Pathogenicity of Escherishia coli Isolated from Ducklings

Abstract:A suspected E. coli from ducklings was isolated in Jingzhou of Hubei province. After selective culturing, biochemical test, PCR identification, regression test and medicine-resistance test, it was identified to be Escherishia coli from ducklings with high resistance to several antibiotics. Subsequently, some 15 day-old ducklings were infected with the E. coli isolates by lumbar injection for pathogenicity test. The results showed that the mortality of infected ducklings was 100%. In the dead ducks fibrinous pericarditis, glissonities and air sacculitis were also observed. It proved that this E. coli isolate was in high pathogenicity.

Key words:Duckling; Escherichia coli; Isolation and Identification; Pathogenicity 鸭大肠杆菌病是影响养鸭场生产效益的主要疾病之一?据文献资料显示[1,2],鸭

大肠杆菌病在我国不同类型的养鸭场中普遍存在,流行广泛,而使用抗生素防治该病,又易产生抗药性,并且从这些报道看,我国分离到的鸭源性大肠杆菌的血清型众多,不同地区差异较大?伴随着规模化养鸭的发展和区域集约化养殖的扩大,加上环境与水源的污染加重,该病的危害日益严重,往往一个场发病,能导致集养区成片流行,而且鸭大肠杆菌病与传染性浆膜炎混合感染较多,症状与病变较相似而不易区分,还具有垂直传播的特点,这都会给养殖户造成重大的经济损失,因此对鸭大肠杆菌病的防治是非常重要的[3,4]?

本研究从湖北荆州五三农场病变特征为纤维素性心包炎和肝周炎的患病的雏鸭脑内分离到1株细菌,进行生化特性试验?药敏试验?细菌16S rRNA序列测定和动物回归试验,鉴定为致病性大肠杆菌,并用已分离鉴定的大肠杆菌经腹腔注射途径感染15日龄雏鸭,观察雏鸭感染后的临床症状?病理变化,进一步了解此分离菌株的病理变化?致病特点,阐明雏鸭感染大肠杆菌后发病特点,为进一步探讨其发病机理和临床防治提供资料?

1材料和方法