安徽部分地区猪丹毒杆菌的分离鉴定及生物学特性研究

Isolation, identification and characterization of Erysipelothrix rhusiopathiae in Anhui province

【目的】对安徽省8个不同地区猪场临床疑似猪丹毒病/死猪进行细菌分离鉴定,并研究其生物学特性。【方法】通过形态学及培养特性观察、生化试验、PCR方法对菌株进行鉴定,并进行药物感受性实验及免疫保护实验。【结果】共分离到29株猪丹毒杆菌,源自8个地区的猪丹毒杆菌分离菌具有较一致的形态特征和相似的生化特性。对29株猪丹毒杆菌进行18种常用抗菌药物的药敏试验,结果显示分离菌对氨苄西林、头孢曲松敏感率均达100%,其次是青霉素93%、红霉素89.7%和头孢噻肟75.9%,对其他13种药物则表现不同程度的耐药性。8株不同地区猪丹毒杆菌分离菌的LD50在(14.30?2.36)×102 CFU/mL之间,显示分离菌对小鼠均具有较强的致病力。商品化猪丹毒G4T10株弱毒疫苗2次颈部皮下免疫小鼠后,分别用剂量为100 LD50的8株猪丹毒杆菌分离菌腹腔攻毒小鼠,免疫保护率为100%。【结论】安徽地区猪丹毒发生有上升趋势,不同地区的猪丹毒杆菌分离菌具有较为一致的生物学特性,青霉素类和头孢类抗菌药物有显著疗效,使用猪丹毒G4T10株弱毒疫苗可产生有效的免疫保护力。

[Objective] This study was to isolate, identify and characterize pathogenic bacteria from Erysipelothrix rhusiopathiae suspected cases or dead pigs from 8 different areas in Anhui Province.[Methods] The morphological, culture characteristics, biochemical test, PCR were applied todetermine them, and then the drug-sensitivity test and protective immunity test were done. [Results]Twenty-nine E. rhusiopathiae strains were isolated; they were the same in morphological and biochemical properties. They were highly sensitive to Ampicillin and Cefatriaxone with 100%inhibitory among 18 antibiotics by drug-sensitivity test. The inhibition of Penicillin, Erythomycin and Cefotaxime was 93%, 89.7%, 75.9% respectively, though resistance to the other 13 antibiotics developed at different degree. The 8 isolates from different areas were highly lethal to mice, with LD50 between 14.30×10^2 and 2.36×10^2 CFU/mL. After immunized with commercial attenuated vaccine E. rhusiopathiae G4T10 strain through neck hypodermic injection, and challenged with 100 LD50 by lumbar injection, mice were 100% protected. [Conclusion] Isolated strains from different areas have the same biological characters, they were sensitive to beta lactam antibiotics. Commercial attenuated vaccine of G4T10 strain of E. rhusiopathiae can induce immune response to resist it.