黄牛阿氏肠杆菌的分离鉴定及生物学特性研究

为查明广西某牛场病死黄牛的病死原因,提供科学的综合防治措施,用细菌分离、生化鉴定、细菌16S rRNA测序、体外药敏试验、常见病原的PCR检测等方法对送检的病料进行检测。结果显示,化脓隐秘杆菌、多杀性巴氏杆菌、溶血性曼氏杆菌、肺炎克雷伯菌、牛副流感病毒3型、牛病毒性腹泻病毒、牛支原体和牛传染性鼻气管炎病毒PCR检测结果均为阴性。而从出血肺组织中分离到1株能引起小鼠致死的短杆状革兰阴性菌,该细菌在血琼脂平板上呈灰白色菌落,不溶血;在麦康凯培养基上呈圆形灰色、轻度隆起、光滑湿润、边缘整齐、直径为0.2 mm^0.3 mm的针尖状小菌落;在营养肉汤中生长呈絮状物浑浊。生化鉴定发现其符合阿氏肠杆菌的生化特性,16S rRNA测序结果显示该菌与阿氏肠杆菌的基因序列同源性为99%。体外药敏试验结果显示该菌仅对头孢类药物敏感,头孢类药物作用效果强度为头孢曲松钠>头孢地嗪钠>头孢哌酮钠舒巴坦钠。

Isolation,Identification and Biological Characteristics of Enterobacter asburiae from Cattle

In order to find out the dead cause of cattle in a cattle farm in Guangxi,and provide scientific comprehensive prevention and control measures,this study used bacterial isolation,biochemical identification,bacterial 16 SrRNA sequencing,in vitro drug susceptibility test,common pathogen PCR detection and other methods to detect the submitted samples.The test results showed that PCR detections of Pseudomonas pyogenes,Pasteurella multocida,Mannella haemolyticus,Klebsiella pneumoniae,bovine parainfluenzavirus type 3,bovine viral diarrhea virus,Mycoplasma bovis,bovine infectious rhinotracheitis virus,were all negative.A short rod-shaped Gram-negative bacterium which could kill the mice was isolated from the hemorrhagic lung tissue.The bacterium had gray-white colony on the blood agar plate,and was no hemolysis;it was round gray and slightly elevated on Macconkey medium.It was smooth and moist,with neat edges and small needle-shaped colonies with a diameter of 0.2 mm-0.3 mm.It grew with flocculent turbidity in nutrient broth.Biochemical identification found that it is consistent with the biochemical characteristics of Enterobacter asburiae.16 SrRNA sequencing results showed that the gene sequence homology with Enterobacter asburiae is 99%.The results of in vitro drug susceptibility test showed that the bacterium was only sensitive to cephalosporins,and the intensity of cephalosporin action was:ceftriaxone sodium>cefodizime sodium>cefoperazone sodium sulbactam sodium.