鲤鱼细菌性败血症的病原菌鉴定及疫苗研制

Pathogen identification and vaccine production of bacterial septicemia in carp

目的分离鲤鱼细菌性败血症的致病菌株,制备疫苗,为批量生产提供技术依据。方法对从患细菌性败血症的鲤鱼(Cyprinus Carpio Linnaeus)的肝、脾、肾分离出致病菌株进行鉴定,在不同条件下对培养液的培养条件和疫苗的灭活条件进行优化,并通过实验室和田间的攻毒保护实验检测疫苗的免疫效果。结果分离的致病菌株经生理生化鉴定、人工感染实验和16S rRNA序列分析,结果为嗜水气单胞菌(Aeromonas hydrophi-la),选择对鲤鱼半数致死量为2.5×107cfu/mL的代表菌株制备疫苗,于28℃、振荡培养、pH为7.5的普通肉汤培养基中加1%胰蛋白胨时培养效果最好,在28℃、12h、浓度为0.2%甲醛灭活条件最佳,经比较,免疫组与未免疫组的攻毒保护率差异均有统计学意义(P<0.05)。结论将嗜水气单胞菌灭活疫苗用于鲤细菌性败血症的防治具有发展前景。

Objective The purpose of this study was to isolate the pathogens from the carp in the risk of bacterial septicemia and make into vaccine,in order to provide technical basis for mass production.Method The bacterial strains were isolated and identified from liver,spleen and kidney carps,optimized the culture medium and the conditions of vaccine inactivating at different condition,immune efficacy of vaccine was examined by filed and laboratory protected against challenge assays.Results Strains were identified as Aeromonas hydrophila by physiological and biological studies,artificial infection and16S rRNA sequence analysis.Selected strong virulence strains which the median lethal dose was 2.5×107CFU/g to healthy carp make into vaccine with 0.2% formaldehyde at 28℃ for 12h,bacterial liquid was cultural by pH7.5,1% tryptone broth,28℃,180r/min.The survival rate was different between two immunized groups and control groups（P0.05）.Conclusions The results showed that there is a potential to apply inactivated vaccine of Aeromonas hydrophila strain to prevention of carp suffering with bacterial septicaemia.