鼋摩氏摩根氏菌的鉴定及致病性

本研究旨在寻找引起鼋(Pelochelys bibroni)体表溃烂的致病因子。从北京地区自然患病的鼋体表分离到致病菌株YB0428,采用生理生化鉴定结合16S rRNA基因序列的系统发育学分析确定该菌株的系统发育地位。同时采用琼脂扩散法对抗菌类药物的敏感性进行测定。菌株YB0428与Morganella morganii HX081027的16SrRNA基因序列相似性达94%;结合形态特征与生理生化测定结果,该菌为革兰阴性杆菌,氧化酶阴性;V-P试验反应阴性;柠檬酸盐试验阴性;吲哚阳性;脲酶阳性;鸟氨酸脱羧;不产生赖氨酸和精氨酸双水解酶。在37种抗菌类药物对该菌的抑菌试验中,奈替米星、羧苄西林、哌拉西林等10种药物的抑菌效果较好。确定该菌株在分类上属于摩氏摩根氏菌(Morganella morganii)。为进一步防治鼋细菌性病害提供了科学依据。

Isolation and Identification of Pathogenic Morganella morganii Isolated from Infected Soft-shelled Turtle (Pelochelys bibroni)

Our study aimed at searching for the pathogenic factor,which cause soft-shelled turtle(Pelochelys bibroni) disease.A pathogenetic bacterial strain YB0428 was isolated from naturally infected soft-shelled turtle in Beijing.The strain was identified according to its physiological,biochemical properties and the sequence analysis of 16S rRNA gene.The drug sensitivity was detected by Kirby-Bauer’s agar diffusion method.Based on the result of 16S rRNA sequence analysis,the strain YB0428 shares 94% sequence identity with the type strain HX081027 of Morganella morganii.The morphological characteristics of the strain were gram-negative.The results of physiological and biochemical tests showed Kovacs,Citrate and Voges-Proskauer(V-P) tests were negative.Indole,Urease and Ornithine decarboxylase tests were positive.Lysine decarboxylase and arginine dihydrolase tests were negative.The result of drug sensitive tests showed that among 37 antibiotics,Netilmicin,Carbenicillin,Piperacillin etc.had better inhibitive effect on the strain.The isolated strain YB0428 was identified as Morganella morganii.The results will provide evidences for further caring the diseases of soft-shelled turtle(Pelochelys bibroni).