台湾泥鳅死亡致病菌的分离鉴定及药敏试验

为确定捕捞转场后造成台湾泥鳅（Paramisgurnus dabryanus ssp.Taiwan）死亡的病原，本试验对台湾泥鳅进行病理解剖、病原分离。对分离菌进行形态学观察、生理生化特性测定及16S rDNA基因测序鉴定，并进行人工感染试验、药敏试验。结果显示，从泥鳅肝脏、脾脏、肾脏及肠道组织中分离到形态一致的优势菌株，经纯化保存，命名为XJC。菌株XJC葡萄糖发酵、D-葡萄糖、鸟氨酸、苯丙氨酸及尿素利用阳性，其他所测生化指标均为阴性，与摩氏摩根菌（Morganella morganii）一致；16S rDNA基因序列与摩氏摩根菌相似性达99.6%，被鉴定为摩氏摩根菌。感染试验结果表明，菌株XJC对台湾泥鳅具有致病性，被感染的泥鳅出现了肠道充血典型病理变化。从发病泥鳅体内分离到与菌株XJC一致的菌株，可以判定菌株XJC是泥鳅病原菌。药敏试验结果表明，菌株XJC对氨基糖苷类、喹诺酮类及第三代头孢类药物表现出敏感，对四环素、青霉素、红霉素、多肽类、呋喃唑酮、洁霉素及第一、第二代头孢类药物均等表现耐药，生产中可选用氨基糖苷类、喹诺酮类药物进行摩氏摩根菌疾病的防治。本试验结果可为台湾泥鳅摩氏摩根菌病诊断和防治提供参考。

A Isolation,Identification and Drug Sensitivity Test of a Pathogen Causing Death of Taiwan Loach (Paramisgurnus dabryanus ssp.Taiwan)

In order to determine the cause of death of Taiwan loach (Paramisgurnus dabryanus ssp.Taiwan) after the transfer of fishing,the pathological anatomy and pathogen isolation of Taiwan loach were carried out.Morphological observation,physiological and biochemical characteristics determination,16S rDNA gene sequencing and identification were carried out for the isolated bacteria,as well as artificial infection test and drug sensitivity test.The results showed that the dominant strains were isolated from the liver,spleen,kidney and intestine of loach and named as XJC after purification and preservation.The strain XJC was positive in glucose fermentation,D-glucose,ornithine,phenylalanine and urea utilization,and the other biochemical indexes were negative,which was consistent with Morganella morganii.The similarity of 16S rDNA gene sequence with Morganella morganii was 99.6%,which was identified as Morganella morganii.The results of infection test showed that XJC had pathogenicity to the loach,and the infected loach had typical pathological changes of intestinal congestion.The strain XJC was identified as the pathogen of loach.The results of drug sensitivity test showed that XJC was sensitive to aminoglycosides,quinolones and the third generation cephalosporins,and equally resistant to tetracycline,penicillin,erythromycin,polypeptide,furazolidone,lincomycin and the first and the second generation cephalosporins.Aminoglycosides and quinolones could be selected for the prevention and treatment of Morgan's disease.The results of this experiment could provide a reference for the diagnosis and control of Morganella morgensis in Taiwan loach.