摘要
2024年5月,浙江省衢州市某养殖场光唇鱼(Acrossocheilus fasciatus)突发疾病,发病快,死亡率高。为探究病因及致病机理,从患病光唇鱼的肝脏、脾脏和肾脏中分离出1株优势菌GC-01。人工感染实验显示,感染后实验鱼发病的临床症状与自然患病相似,口腔、鳃盖周边发红,尾鳍及尾柄部位发红肿胀,肝脏呈土黄色,肠道水肿。结合形态学、生理生化特性以及16S rRNA序列分析,综合判定菌株GC-01为弗氏柠檬酸杆菌(Citrobacter freundii)。菌株GC-01的半数致死浓度(LD50)为8.41×10^(5)CFU/m L,毒力基因检测发现该菌株携带cfa、ureF、ureD、ompX等4种毒力基因。药敏结果显示,分离菌株GC-01对庆大霉素、链霉素、氟苯尼考、强力霉素、恩诺沙星、新霉素、卡那霉素、四环素、氨苄西林等9种抗菌药物敏感,对头孢他啶、青霉素、林可霉素、阿莫西林和复方新诺明等5种抗菌药物耐药;耐药基因检测表明,该病原菌携带sul1、sul2、gyra、parC等4种耐药基因。研究表明,弗氏柠檬酸杆菌GC-01分离株携带多种毒力基因和耐药基因,对光唇鱼具有高致病性,可造成光唇鱼机体损伤甚至死亡。
To investigate the causes of a disease outbreak of Acrossocheilus fasciatus in Quzhou,Zhejiang Province in May 2024.The dominant bacterial colony GC-01 was isolated from the liver,spleen,and kidney tissues of the diseased A.fasciatus.In the artificial infection experiment,the clinical symptoms of the infected fish were similar to those of natural disease,such as redness in the mouth and around the operculum,redness and swelling in the caudal fin and caudal stalk,earth yellow liver,and intestinal edema.According to the morphological,physiological and biochemical characteristics and 16S rRNA sequence analysis,the strain GC-01 was identified as Citrobacter freundii.This strain carried four virulence genes,cfa,ureF,ureD,and ompX,with a half-lethal concentration of 8.14×10^(5)CFU/mL.GC-01 was sensitive to gentamicin,streptomycin,florfenicol,doxycycline,enrofloxacin,neomycin,kanamycin,tetracycline,and ampicillin,while it has developed resistance to ceftazidime,penicillin,lincomycin,amoxicillin,and trimethoprim sulfamethoxazole,which carried four drug resistance genes,including sul1,sul2,gyra,and parC.In conclusion,GC-01 carries a variety of virulence genes and drug resistance genes,and is highly pathogenic to A.fasciatus,which can cause body damage and even death.
作者
方文斌
范峰林
吴子龙
郑安瑞
李倩慧
叶嘉政
郑善坚
FANG Wenbin;FAN Fenglin;WU Zilong;ZHENG Anrui;LI Qianhui;YE Jiazheng;ZHENG Shanjian(College of Bioscience,Zhejiang Normal University,Jinhua 321004,China;Jiangshan Aquaculture Development Service Center,Jiangshan 323000,China)
出处
《水产学杂志》
2025年第6期44-50,共7页
Chinese Journal of Fisheries
基金
浙江省农业重大技术协同推广计划(2024 ZDXT14)
江山市农业农村局项目[江农合(2024)048号]。
关键词
光唇鱼
弗氏柠檬酸杆菌
细菌鉴定
毒力基因
耐药基因
Acrossocheilus fasciatus
Citrobacter freundii
bacterial identification
virulence genes
resistance genes
