绿鳍马面鲀烂嘴症致病菌的分离鉴定及药敏试验

为确定绿鳍马面鲀烂嘴症的致病菌及筛选敏感药物,通过平皿划线法将患病组织内的细菌进行分离纯化,得到1株优势菌,命名为QZG3。该菌株在硫代硫酸盐柠檬酸盐胆盐蔗糖琼脂(TCBS)弧菌选择性培养基上为绿色、圆形、黏稠状菌落,经革兰氏染色判断为革兰氏阴性菌；对该菌株的16S rRNA基因进行测序、鉴定,并经系统进化树分析,发现该菌株与阿尔法克弧菌(Vibrio alfacsensis)聚为1支,因此判断该菌株为阿尔法克弧菌。人工回感试验表明,该菌株为绿鳍马面鲀烂嘴症的致病菌；药敏试验结果显示,该菌株仅对氟苯尼考、恩诺沙星两种抗生素高度敏感,对土霉素、青霉素、头孢氨苄、庆大霉素、卡那霉素、四环素以及红霉素均表现出耐药性。因此建议养殖生产上选用氟苯尼考和恩诺沙星进行药物防治。

Isolation,identification and drug sensitive test of pathogen causing Thamnaconus modestus rotten mouth

In order to determine the pathogen causing Thamnaconus modestus rotten mouth and screen sensitive drugs,a dominant strain named QZG3 was obtained by isolating and purifying the bacteria in the diseased tissue by plate culture method.The strain was green, round and viscous on the selective medium of thiosulfate citrate bile salts sucrose(TCBS) agar,and was identified as gram-negative bacteria by gram staining.The 16S rRNA gene of QZG3 was sequenced and identified.Phylogenetic tree analysis showed that QZG3 and Vibrio alfacsensis clustered into a branch,so the strain was identified as V. alfacsensis.Artificial response test showed that QZG3 was the pathogen causing T. modestus rotten mouth.Results of drug sensitivity test showed that the strain was highly sensitive to only two antibiotics,flfenicol and enrofloxacin,and resistant to oxytetracycline,penicillin,cephalexin,gentamicin,kanamycin,tetracycline and erythromycin. Therefore,florfenicol and enrofloxacin are recommended for drug prevention and control in the farming.