枯草芽孢杆菌二联活菌的生物学特性及其基因组分析

摘要 目的：枯草芽孢杆菌二联活菌是我国临床上应用比较广泛的微生态制剂。为了评估该种微生态制剂对肠道健康的影响，对其含有的两种细菌枯草芽孢杆菌R-179和屎肠球菌R-026的生物学特性和耐药性展开研究。方法：通过细菌生长曲线的测定，分析了两种细菌在好氧和厌氧条件下生长状况和氧化还原电位，并对两种菌的抗生素耐药特性进行了检测；同时采用三代测序技术对两株细菌进行了基因组测序和生物信息学分析。结果：枯草芽孢杆菌R-179在好氧条件下生长，厌氧情况下并不生长，其在肠道环境中可以有效的消耗氧气；两种菌混合培养可以有效降低氧化还原电位，耐药性分析表明该两种菌对青霉素、万古霉素敏感，基因组分析表明该两种菌并不含有耐药转移元件，而且枯草芽孢杆菌还分泌多种抗菌活性物质。结论：利用现代研究手段，结合最新测序技术，挖掘和探讨了枯草芽孢杆菌二联活菌在肠道中的作用机制，为枯草杆菌二联活菌用于临床消化道疾病治疗的机理研究和安全应用评价提供了重要的临床参考。

Characterization and Genome Analysis of Enterococcus Faecium and Bacillus Subtilis

ABSTRACT Objective: Live Combined Bacillus subtilis and Enterococcus faecium probiotics is widely used in clinical treatment in China. In order to evaluate the effects of the probiotics on intestinal health, the biological characteristics and drug resistance of B. subtilis R-179 and E. faecium R-026 were investigated. Methods: In this study, the growth curve and redox potential of the two strains were measured under aerobic and anaerobic condition. Moreover, the drug resistance of the strains was investigated by automatic microbial identification instrument; Furthermore, the genomes were sequencing by Pacbio sequel and bioinformation analyses was done. Results: The results showed that B. subtilis could grow under aerobic conditions, but does not grow under anaerobic conditions. It can effectively consume oxygen in the intestinal environment; the mixed co-culture of the two strains effectively reduced the oxidation-reduction potential, and the drug resistance analysis indicated the two strains were sensitive to penicillin and vancomycin. Genomic analysis suggested that the two strains did not contain resistance transfer elements, and B. subtilis also secretes a variety of antibacterial active substances. Conclusion: Using modern research methods and the latest sequencing technology, the mechanism of live Combined B. subtilis and E. faecium Granules in gut was explored and discussed, which is of important clinical reference for the mechanism research and safety application evaluation of live combined bacteria in the treatment for digestive tract diseases.