3株猪源绿色气球菌的分离鉴定

Isolation and Identification of Three Aerococcus viridans Strains from Swine

为确定云南省不同地区3个猪场仔猪发生非创伤性四肢运动障碍的病原因素,无菌采集病死仔猪深部组织样品,采用血琼脂分离培养病原菌,随后对分离菌株做形态观察、生化试验、药敏试验及16S rRNA基因测序分析。结果:从3个猪场病料中均分离到菌落及个体形态一致的细菌,其16S rRNA基因序列与NCBI中7株绿色气球菌参考菌株的同源性均在99%以上,据此判定为绿色气球菌(Aerococcus viridans);3个分离菌株均对克拉霉素、头孢曲松和青霉素敏感,对复方新诺明、庆大霉素和卡那霉素耐药。鉴于未见绿色气球菌单独有强致病力的报道且病死猪有检出猪瘟病毒或猪肺炎支原体感染的情况,研究结果证实绿色气球菌是危害猪健康养殖的重要机会致病菌,并提示其与仔猪非创伤性四肢运动障碍有关。

In order to determine the pathogenic agent causing non-traumatic limb disability of piglets from 3 pig farms in different areas of Yunnan Province,the samples from deep tissues of dead piglets were aseptically collected for pathogen isolation using blood agar and the resulting bacterial isolates were then subjected to morphological examination,biochemical tests,drug susceptibility tests and sequencing of 16S rRNA gene.Consequently,bacteria obtained from the samples of the 3 pig farms had the same colony and individual morphology,and their 16S rRNA gene sequences shared a higher than 99%homology with 7 reference strains of Aerococcus viridans deposited in NCBI,which proved that the isolates were A.viridans.The 3 isolates were sensitive to clarithromycin,ceftriaxone and penicillin,and resistant to cotrimoxazole,gentamicin and kanamycin.In view of no reports that A.viridans itself had high pathogenicity and infection caused by classical swine fever virus or Mycoplasma hyopneumoniae was detected in some dead cases,the results here proved that A.viridans could be an important opportunistic bacterium that did harm to the health of pigs and indicated that this bacterium was involved in the non-traumatic limb disability of piglets.