1株奶牛源约翰逊不动杆菌的分离鉴定

旨在了解从奶牛垫料中分离得到1株革兰阴性菌的病原特征，本研究通过形态学观察、生化试验、染色镜检、16S rDNA同源性分析等方法对分离菌进行鉴定，并采用药敏试验测定药物敏感性，小鼠攻毒试验确定分离菌株毒力情况。结果表明，分离菌为革兰阴性菌；扩增的16S rDNA序列长度为1 283 bp，与约翰逊不动杆菌的核苷酸相似性大于99%；分离菌株对小鼠有较强的致病性，试验组小鼠死亡率达80%。分离菌对链霉素、复方新诺明等6种药物敏感，对头孢噻肟、头孢呋辛中度敏感，对青霉素、红霉素等4种药物耐药。本研究从奶牛垫料中分离到1株约翰逊不动杆菌，为奶牛源约翰逊不动杆菌的防治和研究提供了参考依据。

Isolation and Identification of a Strain Acinetobacter johnsonii from Dairy Cow

In order to understand the pathogenic characteristics of a Gram-negative strain isolated from cows bedding litters.In this study,the isolates bacterium were identified by morphological observation,biochemical test,staining microscopy,16S rDNA homology analysis.Drug sensitivity test was used to determine drug sensitivity,mice attack test was used to determine the virulence of the isolates.The results showed that the isolates were Gram-negative bacteria.The nucleotide sequence of 16S rDNA was 1283 bp,the nucleotide homology with Acinetobacter johnsonii is greater than 99%.The isolated bacterium had strong pathagenicity to mice,the mortality was 80%in test group.The isolates were sensitive to 6 drugs including streptomycin,compound sulfamethoxazole,moderately sensitive to cefotaxime and cefuroxime,resistant to 4 drugs including penicillin and erythromycin.In this study,a strain of Acinetobacter johnsonii was isolated from dairy cow bedding litters,which provides a reference for the prevention and treatment of Acinetobacter johnsonii.