山东地区3型鸭疫里氏杆菌的分离鉴定及主要生物学特性研究

ISOLATION,IDENTIFICATION AND BIOLOGICAL CHARACTERIZATION OF SEROTYPE 3 RIEMERELLA ANATIPESTIFER ISOLATED FROM SHANDONG AREA

从山东某地市典型鸭传染性浆膜炎病例中分离得到8株细菌,经过形态与培养特性观察、生化试验、PCR等方法鉴定为鸭疫里氏杆菌(Riemerella anatipestifer,RA),血清型鉴定发现其中的4株为血清3型,其余4株未定型。血清3型WC6株对雏鸭的致病性试验表明,含菌量约为3×109CFU/mL的菌悬液,对10日龄雏鸭有较强的致病性,感染后症状典型,死亡明显;法氏囊指数低于对照组,差异显著(P<0.05);脾脏指数、胸腺指数都高于对照组,但差异不显著(P>0.05);病理组织学变化则以法氏囊与脾脏出现变性坏死等病变为主,胸腺病变略轻。

Eight bacterial strains were isolated from ducks with typical serositis on farms of Shandong area.Based on the bacterial morphology, Gram＇s staining, growth requirements, colonial appearance, biochemical properties, and genomic PCR analysis, these bacterial strains were identified as Riemerella anatipestifer. Serological analysis revealed that 4 strains belonged to serotype 3 and 2 strains were not serotyped. The 10-day-old ducklings were injected with 3 × 10^9 CFU/mL of WC6 strain of serotype 3. Typical clinical manifestations were observed and some ducklings died soon after injection. The bursal index was lower than non-infected control group and the difference was statistically significant （P〈0. 05）. The indexes of spleens and thymuses were higher than the control group but not significantly different （P〉0. 05）. Pathological changes were mainly located in the bursas and spleens. Slight lesions were observed in thymuses.