两株不同宿主源化脓隐秘杆菌分离鉴定及其plo基因生物信息学分析

Isolation and identification of two Trueperella pyogenes strains from different hosts and bioinformatics analysis of the plo gene

摘要:

【背景】化脓隐秘杆菌是一种能够感染人类及多种动物的条件致病菌，常引起动物的各种非特异性化脓性感染。【目的】探究不同宿主疑似化脓隐秘杆菌感染的菌属种类和病原特性。【方法】对林麝皮下脓肿和鸭跗关节脓肿进行细菌分离，通过革兰氏染色、细菌16S rRNA基因分析等方法对病原菌进行鉴定，通过生长曲线测定、药敏试验和毒力基因检测分析2株病原菌的生物学特性，对溶血素plo基因进行序列分析和结构预测。【结果】分离鉴定到林麝源和鸭源化脓隐秘杆菌各1株，分别命名为FTP-1和DTP-1；生长曲线测定发现，2株病原菌的生长繁殖速度差异较大；药敏试验表明，2株病原菌对β-内酰胺类、磺胺类和利福霉素类抗生素耐药，对氨基糖苷类、喹诺酮类抗生素敏感；毒力基因检测显示，2株病原菌均携带plo、nanH、nanP、fimA和fimE基因，鸭源分离株还携带有fimC基因；生物信息学分析软件预测显示，2株病原菌溶血素plo基因核苷酸序列存在宿主特异性差异，但二者氨基酸序列相同，蛋白结构预测发现化脓隐秘杆菌溶血素(pyolysin, PLO)与胆固醇依赖性溶细胞素家族其他成员之间相似性较高。【结论】在云南宜良地区分离到林麝源和鸭源化脓隐秘杆菌各1株，二者plo基因亲缘关系较近，相关生物学特性分析可为推进该病原菌的研究和防控提供参考。

关键词:化脓隐秘杆菌;分离鉴定;plo;生物信息学

Abstract:

[Background] Trueperella pyogenes is an opportunistic pathogen causing infections in humans and diverse animal species, particularly non-specific purulent infections in animals. [Objective] To characterize the suspected T. pyogenes strains from different hosts. [Methods] Strains were isolated from the subcutaneous abscess of forest musk deer and duck tarsal joint abscess and identified based on Gram staining and bacterial 16S rRNA gene analysis. The biological properties of the two strains were characterized through the analysis of the growth curves, drug sensitivity test, and detection of virulence genes. Then we analyzed the sequence and predicted the structure of the pyolysin gene plo. [Results] The strains isolated from forest musk deer and duck were named FTP-1 and DTP-1, respectively. According to the growth curves, the growth rates of the two were quite different. Drug sensitivity test showed that the two strains were resistant to β-lactams, sulfonamides, and rifamycins and sensitive to aminoglycosides and quinolones. Both strains carried plo, nanH, nanP, fimA, and fimE genes, and DTP-1 also harbored fimC gene. There were host-specific differences in the nucleotide sequence of plo gene between the two strains, but the amino acid sequences of encoded proteins were the same. The pyolysin (PLO) of T. pyogenes was highly similar to other members of the cholesterol-dependent cytolysin family. [Conclusion] One strain of T. pyogenes was respectively isolated from forest musk deer and duck in Yiliang of Yunnan Province, and the plo gene of two strains had close genetic relationship. The biological characteristics can serve as a reference for further research on and prevention and control of the pathogen.

Key words:Trueperella pyogenes;isolation and identification;plo;bioinformatics