黑豚鼠源链球菌的分离鉴定

Isolation and identification of Streptococcus from the diseased Cavia porcellus

为确定南宁市吴圩镇某黑豚鼠养殖场发生死亡的原因,从发病黑豚鼠眼分泌物、囊肿及肺中分离到可疑细菌,经形态观察、生理生化特性测定及16S rRNA序列分析,鉴定该分离菌为马链球菌兽疫亚种。经小白鼠回归试验证实,该分离菌可致死小白鼠。分离菌16S rRNA与马链球菌兽疫亚种(AB104843)的同源性最高,达99.8%。进化树分析显示,该分离菌与马链球菌兽疫亚种(AB104843)、马链球菌马亚种(JQ726495、JQ726496)的遗传关系最近,处于同一分支上。药敏试验显示,该分离菌对氨苄青霉素、氨曲南、头孢拉定、头孢唑啉、头孢氨苄、头孢呋辛、链霉素、卡那霉素等高度敏感,对青霉素、亚胺培南、四环素、多西环素等不敏感。结果表明,马链球菌兽疫亚种16-58是南宁市吴圩镇某黑豚鼠养殖场豚鼠致死的病原菌。

To identify the causative agent infecting Cavia porcellus on a farm in Wuxu town of Nanning,suspect bacteria were isolated from the eye discharge,neck cyst and lungs of diseased Caviaporcellus. Their morphological characteristics,physiological and biochemical characteristics and the results of 16s rRNA gene sequence analysis proved that the pathogenic bacteria were Streptococcus equi subsp, zooepidemicus. In a pathogenic test,the isolate was lethal to adult mice. Their 16S rRNA was closely related to Streptococcus equi subsp. Zooepidemicus（AB104843） with homologies of 99.8~.Phylo- genetic analysis indicated that the isolate was closely related to Streptococcus equi subsp, zooepi- demicus（AB104843） and Streptococcus equi subsp, equi（JQ726495 and JQ726496）,positioning the same bra- nch. The results of antibiotic susceptibility testing demonstrated that the Streptococcus was highly sensitive to ampicillin,aztreonam,cefradine,cefazolin,eephalexin,cefuroxim,streptomycin, kanamycin etc..but resistant to penicillin,imipenem,tetracycline,minocycline etc. These findings suggest that Streptococcus equi subsp. Zooepidemicus 16-58 is the pathogen of the dead Cavia porcellus in Wuxu town of Nanning.