加州鲈源普通变形杆菌分离、鉴定及药敏分析

Isolation, Identification and Drug Sensitivity of Proteus vulgaris From Diseased Largemouth Bass Micropterus salmoides

从广东佛山某养殖场发病死亡的加州鲈Micropterus salmoides肝、脾和肾中分离出2株病原菌(201901141和201901142),经形态学观察、生理生化特性测定、16S r RNA基因序列分析鉴定,通过人工感染试验确定病原,用改进的寇式法计算半数致死剂量(LD50),运用纸片扩散法进行药敏试验,分析加州鲈源普通变形杆菌病原,探明该菌药物敏感性和防治方法。人工感染试验表明,分离得到的2菌株具有很强的致病力,对健康加州鲈的半致死剂量LD50分别为5.13×105CFU/g和6.46×105CFU/g。2株病原菌的形态特征、理化特性都与普通变形杆菌Proteus vulgaris一致,其16S r RNA基因序列与普通变形杆菌同源性最高,综合判定病原菌为普通变形杆菌。药敏试验结果表明,2株菌株对哌拉西林、头孢曲松、四环素等抗生素高度敏感;对羧苄西林等中度敏感;对头孢呋辛、苯唑西林等不敏感。本研究首次报道了普通变形杆菌引发的加州鲈疾病。

Two strains of bacterial pathogens(201901141,201901142)were isolated,and purified from liver,spleen and kidney of diseased largemouth bass Micropterus salmoides in a farm in Foshan,Guangdong province,and identified by morphological,biochemical methods and 16 S r RNA gene sequence analysis.Drug sensitivity was tested by disc diffusion method and LD50 was calculated by the Karber method to provide reference for the prevention and treatment of the bacterial pathogens in largemouth bass.The morphological and biochemical characteristics and 16 S r RNA gene sequence analysis revealed that the bacterial pathogens(201901141,201901142)were identified as Proteus vulgaris,and had the LD50 of 5.13×105 and 6.46×105 CFU/g.The drug sensitivity test showed that the strains were highly sensitive to antibiotics such as piperacillin,ceftriaxone sodium and tetracycline;moderately sensitive to carbenicillin;and insensitive to cefuroxime and oxacillin.The findings were the first time report on the largemouth bass diseasecaused by Proteus vulgaris.