大口黑鲈烂身病病原菌的分离鉴定及其药物敏感性

Isolation,identification and drug sensitivityanalysis of pathogenic bacteria causingrotten disease in Micropterussalmoides

从湖南省醴陵市某大口黑鲈工厂化养殖场中患烂身病的大口黑鲈体表溃疡处分离得到1株病原菌MS315509,经形态学和分子生物学鉴定,确定该病原菌为嗜水气单胞菌(Aeromonas hydrophila)。人工感染结果显示,MS315509对大口黑鲈鱼苗的半数致死剂量为5.47×10^(7)cfu/mL,为弱毒株;MS315509携带细胞兴奋性肠毒素基因(alt)、细胞毒性肠毒素基因(act)和黏附素基因(aha1)3种毒力基因;采用12种抗生素与12种中草药对菌株MS315509进行药物敏感性试验,结果表明MS315509对庆大霉素、头孢拉定、石榴皮、苏木、五倍子、诃子等高度敏感,对四环素、头孢唑啉、卡那霉素、苯唑西林、恩诺沙星、青霉素、强力霉素、链霉素、黄连、艾叶和熟地黄等表现出耐药性。

A bacterial pathogen strain MS315509 was isolated from the surface ulcer ofthe sick Micropterus salmoides(M.salmoides)in a perch farm in Liling City,Zhuzhou City,Hunan Province.The isolate was identified morphologically and molecularly as Aeromonas hydrophila.The results of artificial infection showed that the half lethaldosage of MS315509 inM.salmoidesfry was 5.47×10^(7)cfu/mL.The virulence gene detection showed that the strain MS315509 carried three virulence genes:cytotoxic enterotoxin(alt),excitatory enterotoxin(act)and adhesin(aha1).Drug susceptibility testing of strain MS315509 utilizing 12 antibiotics and 12 herbs showed that the strain MS315509 was highly sensitive to gentamicin,cefradine,Shiliupi,Sumu,Wubeizi,Hezi,and resistant to tetracycline,cefazolin,kanamycin,oxacillin,enrofloxacin,penicillin,vibramycin,streptomycin,Huanglian,Aiyeand Shudihuang.