天津农学院学报 ›› 2026, Vol. 33 ›› Issue (2): 63-68.doi: 10.19640/j.cnki.jtau.2026.02.011

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花鲈弗氏柠檬酸杆菌的分离与鉴定

李春晓, 李修怡, 韩卓然, 罗璋, 孙敬锋通信作者   

  1. 天津农学院 水产学院,天津 300392
  • 收稿日期:2024-09-12 出版日期:2026-04-30 发布日期:2026-05-06
  • 通讯作者: 孙敬锋(1976—),男,教授,博士,主要从事水产动物免疫与疾病防控研究。E-mail:sun_jf@163.com。
  • 作者简介:李春晓(2000—),女,硕士在读,主要从事水产动物免疫与疾病防控研究。E-mail:1904558377@qq.com。
  • 基金资助:
    天津市自然科学基金(23JCQNJC00490); 天津市海水养殖产业技术体系项目(ITTMRS2021007)

Isolation and identification of Citrobacter freundii from Lateolabrax maculatus

Li Chunxiao, Li Xiuyi, Han Zhuoran, Luo Zhang, Sun JingfengCorresponding Author   

  1. College of Fisheries, Tianjin Agricultural University, Tianjin 300392, China
  • Received:2024-09-12 Online:2026-04-30 Published:2026-05-06

摘要: 为确定花鲈(Lateolabrax maculatus)患病的原因,从其肝脏、脾脏和肾脏组织中分离优势菌株,并通过形态学观察、生理生化试验、16S rRNA和gyrB基因序列测定及系统发育学分析进行种属鉴定。后经人工回归感染试验分析其致病性,通过药敏试验分析其对抗生素的耐药情况。结果显示,从病鱼肝脏中分离获得1株优势菌并鉴定为弗氏柠檬酸杆菌(Citrobacter freundii),命名为XY-1。人工回归感染试验证实菌株XY-1是引起本次花鲈患病的病原菌,对花鲈的半数致死量(LD50)为1.89×106 CFU/mL。药敏试验结果显示,菌株XY-1对头孢唑林、庆大霉素、氟苯尼考等9种药物高度敏感,对新霉素、利福平、诺氟沙星3种药物中度敏感,对阿莫西林、氨苄西林、头孢拉定等12种药物耐药。本研究结果可为弗氏柠檬酸杆菌引起的花鲈细菌性疾病诊断及防治提供参考依据。

关键词: 弗氏柠檬酸杆菌, 16S rRNA, gyrB, 花鲈, 分离鉴定

Abstract: In order to determine the cause of the disease of Lateolabrax maculatus, the dominant strains were isolated from the liver, spleen and kidney tissues. The species were identified by morphological observation, physiological and biochemical tests, 16S rRNA and gyrB gene sequencing and phylogenetic analysis. The pathogenicity was analyzed by artificial regression infection test, and the resistance to antibiotics was analyzed by drug sensitivity test. The results showed that a dominant strain was isolated from the liver of diseased fish and identified as Citrobacter freundii, named XY-1. The artificial regression infection test confirmed that strain XY-1 was the pathogen causing the disease of Lateolabrax maculatus, and the median lethal dose LD50 of Lateolabrax maculatus was 1.89×106 CFU/mL. The results of drug sensitivity test showed that strain XY-1 was highly sensitive to 9 drugs such as cefazolin, gentamicin and florfenicol, moderately sensitive to 3 drugs such as neomycin, rifampicin and norfloxacin, and resistant to 12 drugs such as amoxicillin, ampicillin and cefradine. The results of this study can provide a reference for the diagnosis and prevention of bacterial diseases caused by Citrobacter freundii in Lateolabrax maculatus.

Key words: Citrobacter freundii, 16S rRNA, gyrB, Lateolabrax maculatus, isolation and identification

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