致犊牛肺炎牛支原体南疆株的分离鉴定及oppF基因序列分析

本研究旨在调查新疆喀什某规模化奶牛场的犊牛死亡原因,并确定病原体.无菌采集3份因肺炎死亡的犊牛肺脏病料样品.采用牛支原体专用液体培养基和1.0%牛支原体琼脂固体筛选培养基从3份病死犊牛肺脏病料中分离得到2株牛支原体(Mycoplasma bovis,M.bovis),分别命名为M.bovis-NJ-1和M.bovis-NJ-2.通过菌落形态学观察、特异性PCR和oppF测序比对对分离株进行鉴定.结果显示,2个分离株在固体培养基上的菌落呈现典型的"煎蛋状",且Dienes染色特点符合牛支原体菌落着色特征,中心呈深蓝色;PCR能扩增出牛支原体特异的448 bp目的片段;2个分离株的oppF基因序列与牛支原体国际标准株PG45的同源性分别为96.7%和95.3%.结果表明,引起犊牛发病死亡的病原是牛支原体,本研究为犊牛支原体肺炎的快速诊断和防制提供依据.

Isolation and Identification of Mycoplasma bovis Nanjiang Strain Inducing Pneumonia and Sequence Analysis of oppF Gene

This study was to identify the pathogen from calves which showed pneumonia symptoms occurred in a cattle farm of Kashi city in the South of Xinjiang. Three lung specimens were collected from the dead calves. Two isolates (designated as M.bovis-NJ-1 and M.bovis-NJ-2) were isolated from three pneumonic lung tissue samples of calves with Mycoplasma bovis special liquid medium and solid medium. Both isolates were identified as Mycoplasma bovis by the morphologic observation and specific PCR test, respectively. Colonies of two isolates growed on solid medium were typical fried-egg shape and Dienes staining was dark blue. An expected gene fragment of 448 bp specific for Mycoplasma bovis was amplified by PCR. In addition, the oppF genes of the isolates were amplified and sequenced, the homologies of which were 96.7% and 95.3% with reference strain Mycoplasma bovis PG45 available in the GenBank, respectively. The results indicated that Mycoplasma bovis was responsible for the calf pneumonia.