重庆市某肉牛场牛支原体肺炎的诊断

重庆市某肉牛场新进育肥牛群发生以呼吸系统感染为主的传染性疾病,为确诊病因,对表现明显临床症状的病牛进行迫杀,无菌采集肺脏、肝脏、血液和心肌进行病原分离,共分离到4株菌,分别编号为CQ1、CQ2、CQ3、CQ4.经16S rRNA序列比对,CQ1与牛支原体同源性达99.9％,CQ2与羊创伤球菌同源性达99.8％,CQ3、CQ4分别与大肠杆菌和沙门氏菌同源性达99％.通过培养特性、菌落形态观察、牛支原体特异性引物PCR扩增,确定CQ1为牛支原体；药物敏感性试验和动物试验表明,该分离株对环丙沙星、氧氟沙星、四环素、壮观霉素敏感,不致死小白鼠.按牛支原体肺炎临床用药后,疫情很快得到控制,结合实验室检测结果,确认该场爆发的是以牛支原体感染为主的牛支原体肺炎.

Diagnosis of Mycoplasma bovis pneumonia in a beef cattle farm of Chongqing

A respiratory disease emerged in a beef cattle farm of Chongqing,which caused lesions primarily in lungs.Four bacterial isolates(designated CQ1,CQ2,CQ3,CQ4) were isolated from the lung tissues,liver and blood samples,respectively.16S rRNA sequence analysis showed 99.9%,99.8%,99.9% and 99.9% homology between the CQ1 and Mycoplasma bovis,CQ2 and Helcococcus ovis,CQ3 and E.coli,CQ4 and Salmonella,respectively.CQ1 isolate was identificated as M.bovis based on culture characteristics,colonial morphology and specific gene identification by PCR.The drug susceptibility and pathogenicity to animal showed that CQ1 isolate was sensitive to ciprofloxacin,floxacin,etracycline,spectinomycin and non-lethal to mice.Drug treatment and laboratory detection showed the disease was primarily caused by M.bovis.