斑点叉尾肠套叠症病原菌的分离鉴定及药敏试验

Identification and drug sensitive test of the pathogenic bacteria isolated from Ictalurus punctatus intussusceptions disease

从患典型肠套叠症的濒死斑点叉尾(Ictalurus punctatus)肝脏分离到1株病原菌GX-1,经API 20NE鉴定为温和气单胞菌(Aeromonas sobria)。16S rRNA基因测序结果,该菌株与温和气单胞菌NCIMB 12065株的亲缘关系最近,相似性达99.8%。该菌株对健康斑点叉尾鱼种和成鱼均具有很强的致病力,人工感染发病鱼症状与自然病鱼症状基本一致。药敏试验结果表明,GX-1对头孢拉定、先锋必等15种抗生素敏感,对苯唑青霉素和青霉素G耐药。

A bacteria strain GX-1 was isolated from the liver tissue of the dying Ictalurus punctatus with typical symptoms of intussusceptions.The strain was identified as Aeromonas sobria by an API 20NE test.Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain shared the highest similarity （99.8%） with A.sobria NCIMB 12065.The strain was highly pathogenic in both young and adult healthy I.punctatus, and the symptoms of the artificially infected fish were consistent with the naturally infected fish .Drug sensitivity test results showed that the strain GX-1 was sensitive to 15 types of antibiotics including ofloxacin and sulfamethoxazole , but resistant to prostaphlin and penicillin G .It is the first time in China that A.sobria has been isolated from I.punctatus with intussusceptions in this study .