禾花鲤鱼种暴发性死亡征病原菌的分离鉴定及药敏试验

Isolation,identification and drug sensitivity test of pathogen causing fulminant death of Procypris merus fingerling

【目的】明确引起禾花鲤发生暴发性死亡征的病原菌及其耐药性,为有效防控禾花鲤暴发性死亡征提供科学依据。【方法】采用常规方法分离病原菌,以API 20NE生化鉴定与16S r RNA基因序列分析相结合的方法进行鉴定,人工回归感染试验确定分离菌株的致病性,K-B纸片扩散法测定病原菌对药物的敏感性。【结果】从广西全州县患暴发性死亡征禾花鲤的肝脏中分离获得1株优势菌株(TH5),API 20NE生化鉴定和16S r RNA基因序列分析结果显示,分离菌株TH5为简达气单胞菌(Aeromonas jandaei),与简达气单胞菌标准菌株ATCC 49568(NR 119040)和CDC0787-80(NR 037013)的相似度分别为99.9%和99.6%。人工回归感染试验结果表明,菌株TH5是导致禾花鲤暴发性死亡征的病原菌。该菌株对复方新诺明、环丙沙星、多粘菌素B等11种药物高度敏感,对青霉素G、复达欣、先锋霉素VI等8种药物已产生耐药性。【结论】引起广西全州县养殖禾花鲤暴发性死亡征的病原菌是简达气单胞菌,生产中可选用复方新诺明、环丙沙星、多粘菌素B等药物进行防治。

[Objective]In order to provide reference for effective prevention and control of fulminant death for Proeypris merus, the present experiment was conducted to investigate pathogen causing fulminant death of P. merus and its drug-resistance. [Method]The pathogen was isolated by conventional method, then the pathogen was identified based on API 20NE biochemical identification and 16S rRNA gene sequence analysis. Moreover, the pathogenicity of pathogen was determined by artificial infection. The K-B agar diffusion method was used to test drug sensitivity of pathogen. [Result] The results showed that, a dominant strain TH5 was isolated from liver tissue of P. merus with fulminant epidemic disease in Quanzhou, Guangxi, which was identified as Aeromonas jandaei through API 20NE biochemical identification and 16S rRNA gene sequence analysis. And it shared homologies of 99.9% and 99.6% with the standard strain of A. jandaei ATCC 49568（NR 119040） and A. jandaei CDC 0787-80（NR 037013）, respectively. Furthermore, strain TH5 was pathogen causing fulminant death of P. merus, and the strain was highly sensitive to 11 kinds of drugs including eotrimoxazole, ciprofloxacin and polymyxin B, etc. However, it was resistant to 8 kinds of drugs including penicillin G, fortum and cefradine, etc. [Conclusion]The pathogen causing fulminant death of P. merus is A. jandaei in Quanzhou, Guangxi. Besides, drugs such as eotrimoxazole, ciprofloxaein and polymyxin B can be selected to prevent and treat fulminant death in production.