Safety Evaluation of a Novel Strain of Bacteroides fragilis.
Safety Evaluation of a Novel Strain of Bacteroides fragilis.
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DOI：
10.3389/fmicb.2017.00435
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发表时间：
2017
影响因子：
5.2
通讯作者：
Zhi F
中科院分区：
文献类型：
--
作者：
Wang Y;Deng H;Li Z;Tan Y;Han Y;Wang X;Du Z;Liu Y;Yang R;Bai Y;Bi Y;Zhi F
共生的非致突变脆弱拟杆菌赋予宿主强大的健康益处，并且最近被确定为有希望的益生菌候选者。我们之前隔离了B。通过16 S rRNA序列测定和形态学分析，将其鉴定为一个新菌株。我们还确定ZY-312显示出理想的益生菌特性，包括对模拟消化液的耐受性、粘附性和体外安全性。在本研究中，我们的目的是调查ZY-312是否符合益生菌所需的安全性标准，通过全面和系统的评价。因此，发现菌株ZY-312的脂肪酸谱、代谢产物产生和生化活性与B的描述非常相似。fragilis在Bergey的手册。对菌株ZY-312进行了全基因组序列测定，结果表明，菌株ZY-312与ATCC 25285的同源性为99.99%。在ZY-312中鉴定的33个推定的毒力相关因子主要编码结构蛋白和具有生理活性的蛋白，而bft的缺失表明ZY-312是非毒力基因。在正常和免疫缺陷小鼠中均证明了体内安全性。这11个已鉴定的抗生素耐药基因位于染色体上，而不是质粒上，排除了质粒介导的抗生素耐药性转移的风险。ZY-312对头孢吡肟、卡那霉素、链霉素等抗生素均表现出较强的耐药性。最后，值得注意的是，ZY-312在体外传100代后表现出高的遗传稳定性。本研究补充了ZY-312安全性评价的基础工作，并有助于开发第一个来自优势拟杆菌门的益生菌代表。
Commensal non-toxigenic Bacteroides fragilis confers powerful health benefits to the host, and has recently been identified as a promising probiotic candidate. We previously isolated B. fragilis strain ZY-312 and identified it as a novel strain based on 16S rRNA sequencing and morphological analyses. We also determined that ZY-312 displayed desirable probiotic properties, including tolerance to simulated digestive fluid, adherence, and in vitro safety. In this study, we aim to investigate whether ZY-312 meets the safety criteria required for probiotic bacteria through comprehensive and systematic evaluation. Consequently, the fatty acid profile, metabolite production, and biochemical activity of strain ZY-312 were found to closely resemble descriptions of B. fragilis in Bergey’s manual. Taxonomic identification of strain ZY-312 based on whole genome sequencing indicated that ZY-312 and ATCC 25285 showed 99.99% similarity. The 33 putative virulence-associated factors identified in ZY-312 mainly encoded structural proteins and proteins with physiological activity, while the lack of bft indicated that ZY-312 was non-toxigenic. In vivo safety was proven in both normal and immune-deficient mice. The 11 identified antibiotic resistance genes were located on the chromosome rather than on a plasmid, ruling out the risk of plasmid-mediated transfer of antibiotic resistance. In vitro, ZY-312 showed resistance to cefepime, kanamycin, and streptomycin. Finally, and notably, ZY-312 exhibited high genetic stability after 100 passages in vitro. This study supplements the foundation work on the safety evaluation of ZY-312, and contributes to the development of the first probiotic representative from the dominant Bacteroidetes phylum.