青藏高原藏原羚携带海氏肠球菌的特征研究

Characteristics of Enterococcus hirae isolated from Tibetan gazelles in Qinghai-Tibet Plateau

目的研究青藏高原野生动物藏原羚携带的海氏肠球菌特征。方法分离细菌,采用16S rRNA、rpoA基因序列比对方法鉴定藏原羚携带的海氏肠球菌。采用K-B纸片法进行药敏试验;使用COGs、SwissProt、CARD和VFDB等数据库对基因组进行分析;采用MUMmer和TreeBest软件构建单核苷酸多态性系统进化树图。结果从15份藏原羚粪便样品分离到2株海氏肠球菌。生化分析、16S rRNA和rpoA基因序列分析支持其为海氏肠球菌的鉴定。基因组分析发现其携带荚膜多糖基因簇。系统进化树分析提示2株藏原羚源海氏肠球菌分别属于不同的进化分支,且都与动物源性菌株进化关系更近。2株菌对多种常用抗生素敏感。结论青藏高原藏原羚携带的病原菌海氏肠球菌基因组中存在荚膜多糖基因簇,利于其抵抗不利环境因素,提示YL69可能具备在人群中传播的潜力。

Objective To study the characteristics of Enterococcus hirae carried by Tibetan gazelles in Qinghai-Tibet Plateau.Methods Bacterial isolation,16S rRNA and rpoA gene sequence analysis and whole genome analysis were conducted.K-B disk method was used for drug sensitivity test.COGs,SwissProt,CARD and VFDB databases were used for genome analysis.Software MUMmer and TreeBeST were used to construct the phylogenetic tree based on single nucleotide polymorphisms(SNP).Results Two strains of E.hirae were isolated from 15 stool samples of Tibetan gazelles.The identification was supported by biochemical analysis,full-length 16S rRNA sequence analysis and whole genome analysis.Genomic analysis showed that the strains carried capsular polysaccharide gene cluster,which was recognized as virulence gene.Phylogenetic analysis based on SNPs indicated that two strains of E.hirae from Tibetan gazelle belonged to two clades,which were closer to animal strains,and the strains were sensitive to many commonly used antibiotics.Conclusion E.hirae isolated from Tibetan gazelles in Qinghai-Tibet Plateau carried capsular polysaccharide gene cluster,which was favorable for environment adaption.E.hirae strains showed sensitivity to multi-antibiotics.The study results indicated that YL69 has the potential to spread in humans.