羊属链球菌的分离鉴定及其致病性的初步研究

Isolation,identification and primary study of pathogenicity of Streptococcus from goats

对江苏省某山羊场送检的样品通过细菌分离、生化试验获得1株溶血性链球菌,并将其命名为wx-13。16SrRNA序列分析发现,此分离菌与链球菌新亚种羊属链球菌代表株Streptococcus ovis sp.的同源性最高,达95.5%,归类于新分支。用23种常用抗菌药物的纸片法对该分离菌进行药敏试验,结果显示,该菌对氟苯尼考、氨苄青霉素、红霉素等11种药物产生抗药性,对阿米卡星、先锋霉素Ⅵ和四环素中度敏感,对其余9种抗生素敏感。动物致病性试验结果表明,该分离菌对小白鼠有强致病性,半数致死量为6.30×108 CFU/kg。上述试验结果为羊属链球菌的防治以及链球菌新亚种的进一步研究提供了参考。

One pathogenic bacterium strain named as wx-13 was isolated from clinical specimens from goats in Jiangsu Province,was characterized by phenotypic and molecular taxonomic methods.The bacterium Shared 99%identity with Streptococcus ovis sp.RD through comparing the sequence of 16 SrRNA gene and it was classified a new subspecies.By the drug resistance test,the result showed that wx-13 was resistant to 11 drugs,such as florfenicol,ampicillin and erythromycin,respectively;was moderately sensitive to amikacin,cephalosporinⅥ and tetracycline;and was highly sensitive to another 9antibiotics,such as rifampicin,ciprofloxacin and carbenicillin.The interpretation of pathogenic trial showed that wx-13 had highly virulence to mice with LD50 of 6.30×108 CFU/kg.This study on Streptococcus may pave the way for the further study of the new subspecies.