新疆阿克苏地区某奶牛场温氏支原体感染状况的调查

Investigation of Mycoplasma wenyonii Infection in a Dairy Cattle Farm of Aksu Xinjiang

温氏支原体是引起牛嗜血支原体病的主要病原之一,对新疆阿克苏地区某奶牛场牛温氏支原体的感染状况进行了检测调查。选择临床健康的1岁~2岁奶牛12头进行血液样本采集,经血液涂片染色,在显微镜下观察红细胞是否出现形态变化;同时提取血液样本全基因组DNA,通过PCR方法检测温氏支原体的核酸并进行序列分析,鉴别检测梨形虫和无浆体核酸。结果发现,12份血液涂片样本经显微镜观察,有1份样本中的红细胞呈明显星芒状,疑似支原体或其他病原体感染;分别基于牛温氏支原体、梨形虫和无浆体SSU rRNA基因的PCR检测结果显示,有3份血液样本呈现牛温氏支原体核酸阳性(含显微镜观察红细胞异常的1份样本),PCR产物序列分析发现,均与温氏支原体分离株序列(FJ375309)同源性为100%;梨形虫和无浆体均为阴性;系统发育分析显示,所获序列与温氏支原体同处一个进化支上,与其他常见嗜血支原体种类处于不同分支上。通过对红细胞形态变化的观察、牛温氏支原体的PCR检测和序列分析,证实该牛场存在牛温氏支原体的感染。研究结果为新疆地区牛嗜血支原体病的流行病学调查、防控提供了基础材料。

Mycoplasma wenyonii is a pathogenic organism of haemoplasmosis in cattle.In this study,the infection status of Mycoplasma wenyonii was investigated in a dairy farm of Aksu,Xinjiang.Blood samples were collected from 12 clinical healthy cattle aged 1-2 years to observe morphological changes of red blood cells via microscopic evaluation of Wright stained smears.Mycoplasma wenyonii,Piroplasma and Anaplasma spp.were detected by using the nested polymerase chain reaction(PCR)assay and the 16S rRNA sequencing method.Results showed that the red blood cells were stellate-shaped in one of the 12 blood samples via microscopic observation.Furthermore,based on the SSU rRNA gene of M.wenyonii,three samples were positive by PCR(including the positive sample of the microscopic examination),while Piroplasma and Anaplasma spp.were not found at the SSU rRNA gene,respectively.The sequences of the three positive samples shared 100%homology of the sequence from an isolate of M.wenyonii in Chongqing(GenBank accession number FJ375309).Phylogenetic analysis showed that the obtained sequence was on the same clade as M.wenyonii,and far from other haemotrophic mycoplasma branches.Through the observation of the morphological changes of red blood cells,PCR detection and sequence analysis,it was confirmed that M.wenyonii is the causative agent of haemotrophic mycoplasma infection in the investigated farm.This study provided basic materials for the epidemiological investigation,prevention and control of bovine haemoplasmosis in Xinjiang.