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从广东佛山、广州两地养殖场患内脏类结节病杂交鳢(Channa maculata♀×C.argus♂)内脏器官分离到2株细菌,纯化培养后获得2个分离株,编号为WL-1和WL-2,对分离菌株进行了细菌鉴定、致病性分析及药敏实验。应用常规生理生化鉴定和ATB系统细菌自动鉴定仪对分离菌株进行细胞形态学、理化特性分析,初步判定所分离菌为舒伯特气单胞菌。采用16S rRNA基因、DNA促旋酶的B亚单位蛋白(gyrB)基因对分离菌株进行DNA分子鉴定,结果显示,两个菌株间的16S rRNA基因序列相同,gyrB基因序列同源性为99.7%;分离菌株与GenBank上登录的舒伯特气单胞菌16S rRNA基因序列和gyrB基因序列同源性均最高,达99%以上;分离菌株在系统进化树上与舒伯特气单胞菌聚为一族,进一步确认分离株为舒伯特气单胞菌。人工感染健康鱼后出现与自然发病相似的内脏类结节病症状,从发病鱼内脏组织再分离的细菌特性与原感染菌相同。综合理化特性分析、基因鉴定和人工感染实验确认舒伯特气单胞菌是杂交鳢内脏类结节病的致病菌。药敏实验发现分离菌株对头孢唑啉、庆大霉素等14种药物敏感;对青霉素G、苯唑西林2种药物耐受。
Two strains of bacteria were isolated from the visceral organs of Channa maculata × C.argus♂ in farms in Foshan and Guangzhou, Guangdong province. Two isolates were obtained after purification and were identified as WL-1 and WL-2, the isolates were identified bacteria, pathogenicity and susceptibility testing. The morphological and physico-chemical properties of the isolated strains were analyzed by conventional physiological and biochemical identification and ATB system automatic biochemical analyzer. It was initially determined that the isolated bacteria was Aeromonas Schizandrae. The 16S rRNA gene and gyrB gene of DNA gyrase were used to identify the DNA of the isolates. The results showed that the 16S rRNA gene sequences of the two strains were identical, and the homology of the gyrB gene was 99.7%. The isolates had the highest homology of 16S rRNA gene and gyrB gene of Aeromonas sobria registered in GenBank, which was more than 99%. The isolates were found to be highly homologous to Aeromonas caviae in the phylogenetic tree Family, further confirmed that the isolates Schulze Aeromonas. Artificial infection with healthy fish appeared with the natural incidence of visceral nodular disease symptoms, from the diseased fish visceral tissue re-isolated bacteria and the original characteristics of the same bacteria. Comprehensive physical and chemical properties analysis, genetic identification and artificial infection experiments confirmed Aeromonas Schubert hybridisation visceral sarcoidosis pathogenic bacteria. Susceptibility experiments found that the isolated strains of cefazolin, gentamicin and other 14 kinds of sensitive drugs; penicillin G, oxacillin two kinds of drug tolerance.