文献类型：期刊文献

中文题名：珍珠龙胆石斑鱼源美人鱼发光杆菌的分离鉴定与致病性分析

英文题名：Isolation,Identification and Pathogenicity Analysis of Photobacterium damselae subsp.damselae from Pearl Gentian Grouper(Epinephelus fuscoguttatus♀×E.lanceolatu♂)

作者：钟小飘[1];陈政思[1];李一[1];陈华谱[1];黄瑜[1];王蓓[1];简纪常[1];蔡佳[1]

机构：[1]广东海洋大学水产学院/南方海洋科学与工程广东省实验室/广东省水产动物病害防控与健康养殖重点实验室/湛江市海洋生态与养殖环境重点实验室,广东湛江524088

年份：2025

卷号：52

期号：4

起止页码：88

中文期刊名：广东农业科学

外文期刊名：Guangdong Agricultural Sciences

基金：国家自然科学基金(U20A2065,32002426,32073006);广东省科技计划项目(2023B0202010016)。

语种：中文

中文关键词：石斑鱼;美人鱼发光杆菌;生化特性;药敏试验;回归感染;致病性;载菌量;毒力基因

外文关键词：grouper(Epinephelus fuscoguttatus♀×E.lanceolatu♂);Photobacterium damselae;biochemical characteristics;drug susceptibility test;recurrent infection;pathogenicity;bacterial load;virulence gene

中文摘要：【目的】分离鉴定1株来自患病珍珠龙胆石斑鱼的病原菌,并对该菌的类型、生理生化特性、药敏特性和致病性开展研究,为其病害防控提供理论基础。【方法】在湛江市某养殖场发现患病石斑鱼,无菌条件下从脾脏中分离得到1株优势菌(OR539201),对该菌株开展形态学观察、16S rRNA基因序列分析及生理生化特性鉴定,进一步开展药敏试验、回归感染试验,并检测其毒力基因。【结果】根据分离菌株的形态学观察、16S rRNA序列分析和生理生化鉴定结果,确定菌株OR539201为美人鱼发光杆菌美人鱼亚种(Photobacterium damselae subsp.damselae)。该菌株在LB平板上呈圆形菌落,形态饱满,光滑均匀。系统发育树结果表明,菌株OR539201与美人鱼发光杆菌聚为一支,亲缘关系最近,同为弧菌属。生化鉴定结果显示,氧化酶活性、尿素、赖氨酸等反应呈阳性,水杨苷、甘露醇等反应呈阴性。药敏试验结果表明,该菌株对多粘菌素、丁胺卡那、头孢曲松等6种抗生素中等敏感,对氧氟沙星、环丙沙星、头孢氨苄等13种抗生素敏感。回归感染试验结果表明,该菌株对石斑鱼具有致病性,人工感染后出现体表溃疡、红色增生结节、肝脏肿大、肠道糜烂、脑部红肿等与自然感染相同的症状。载菌量测定结果显示,试验组石斑鱼脾脏及肝脏菌量明显高于对照组。毒力基因检测结果显示,该致病菌具有磷脂酶活性相关基因(plpV)。【结论】成功从患病石斑鱼中分离得到1株潜在致病菌,鉴定为美人鱼发光杆菌美人鱼亚种,该菌株具有明显致病性,可诱发明显病变、引起鱼类死亡。

外文摘要：【Objective】This study aimed to isolate and identify the pathogenic bacteria from diseased pearl gentian grouper(Epinephelus fuscoguttatus♀×E.lanceolatu♂),characterizing the isolate’s species,physiological and biochemical properties,drug sensitivity profiles,and pathogenicity,thereby providing a theoretical foundation for disease prevention and control.【Method】Diseased groupers were collected from a farm in Zhanjiang City.Under aseptic conditions,a dominant bacterial strain(OR539201)was isolated from the spleen of grouper.The morphological observation,16S rRNA gene sequence analysis,physiological and biochemical identification of this isolate were performed.Further analyses including drug susceptibility testing and regression infection experiments,with bacterial loads quantified in the spleen and liver,and virulence genes were also carried out.【Result】The results of morphological observation,16S rRNA sequence analysis,and physiological and biochemical identification indicated that the strain OR539201 was belonged to Photobacterium damselae subsp.damselae.The strain formed circular colonies with rounded,full,and smooth morphology when grow upon the LB agar plate.Phylogenetic analysis of the 16S rRNA gene revealed a close relationship between this strain and P.damselae,which are both belonging to the genus Vibrio.Biochemical tests showed positive reactions for oxidase activity,urea,glycerol,and lysine,while negative reaction for salicin,aesculin,and mannitol.The drug sensitivity test revealed a varying degrees of resistance to different antibiotics,with moderate sensitivity to 6 antibiotics such as polymyxin,amikacin,and ceftriaxone,and sensitivity to 13 antibiotics including ofloxacin,ciprofloxacin,and cefalexin.Regression infection experiments demonstrated that this strain possesses significant pathogenic effects on grouper,inducing surface ulcers,red proliferative nodules,liver enlargement,intestinal erosion,and brain redness that were consistent with natural disease manifestations.Bacterial load in the spleen and liver of groupers in the experimental group were significantly higher than those in the control group,confirming the presence of P.damselae.The virulence gene detection results show that the strain possesses the gene(plpV)related to phospholipase activity.【Conclusion】This study isolated and identified a potential pathogen from diseased groupers successfully,which was identified as P.damselae subsp.damselae.The strain exhibited significant pathogenicity that could induced severe lesions and fish deaths.