不同分离源粪肠球菌的毒力基因比较

Comparison of the virulence genes of Enterococcus faecalis isolated from different environments

摘要:

【背景】粪肠球菌作为一种重要的乳酸菌在食品和医药领域应用广泛。由于很多粪肠球菌为条件致病菌，因此充分了解粪肠球菌基因组中毒力基因(Virulence genes)的携带情况对合理利用该菌种有重要的意义，但目前还没有研究专门报道不同分离源粪肠球菌基因组中毒力基因的携带情况。【目的】了解不同分离源粪肠球菌毒力基因的携带情况，评估分离自自然发酵乳制品中的粪肠球菌的安全性。【方法】利用比较基因组学方法确定107株分离自乳源、血液、尿液、粪便和水源中的粪肠球菌携带毒力基因情况，使用主成分分析比较不同分离源菌株毒力基因的差异，通过卡方检验筛查出环境特异性毒力基因。【结果】在107株粪肠球菌基因组共找到88种编码不同功能蛋白的毒力基因，其中与粘附相关的毒力基因最多。同时发现乳源分离株与其他环境分离株所携带的毒力基因没有显著差异。【结论】乳源分离株中携带的毒力基因与其他环境分离株无显著差异，表明分离自自然发酵乳制品中的粪肠球菌可能同样存在致病风险，因此在食品工业中使用粪肠球菌时一定要对菌株的安全性做全面的评估。

Abstract:

[Background] Enterococcus faecalis, as an important lactic acid bacteria, is widely used in dairy products and pharmacy. However, many E. faecalis isolates are opportunistic pathogen. So it is important to analyze of virulence genes in E. faecalis. [Objective] To study the virulence genes of E. faecalis from different environments and evaluate the safety of E. faecalis isolated from naturally fermented dairy products. [Methods] Comparative genomic analysis was used to determine the virulence genes of 107 strains isolated from dairy products, blood, urine, feces and water. Principal component analysis (PCA) was used to compare the virulence genes of different isolates. The habitat-specific virulence genes were screened by Pearson’s chi-squared test. [Results] A total of 88 virulence genes were identified in 107 genomes of E. faecalis isolates. These virulence genes were mainly involved in adhesion. There was no significant difference in the number of virulence genes between dairy isolates and the other isolates. [Conclusion] The results indicated that the E. faecalis isolated from dairy products were also at risk of pathogenicity. The safety of E. faecalis must be evaluated before using in the food industry.