Casterline Benjamin W, Hecht Aaron L, Choi Vivian M, Bubeck Wardenburg Juliane
a Department of Microbiology , University of Chicago , Chicago , IL , USA.
b Interdisciplinary Scientist Training Program , University of Chicago , Chicago , IL , USA.
Gut Microbes. 2017 Jul 4;8(4):374-383. doi: 10.1080/19490976.2017.1290758. Epub 2017 Feb 23.
The mature microbiome is a stable ecosystem that resists perturbation despite constant host exposure to exogenous microbes. However, the microbial mechanisms determining microbiome development and composition are poorly understood. We recently demonstrated that a non-toxigenic B. fragilis (NTBF) strain restricts enteric colonization by an enterotoxigenic (ETBF) strain dependent on a type VI secretion system (T6SS). We show here that a second enterotoxigenic strain is competent to colonize, dependent on the Bacteroides fragilis pathogenicity island (BFPAI). Additional data showing complex environmental regulation of the Bacteroides fragilis toxin (BFT) suggest that virulence factors may be adapted to modify the colonic niche to provide a strain-specific colonization advantage. We conclude that more complex models of host-microbe-microbiome interactions are needed to investigate this hypothesis.
成熟的微生物群是一个稳定的生态系统，尽管宿主持续暴露于外源微生物，但它能抵抗扰动。然而，决定微生物群发育和组成的微生物机制仍知之甚少。我们最近证明，一种非产毒素脆弱拟杆菌（NTBF）菌株通过依赖VI型分泌系统（T6SS）的产肠毒素脆弱拟杆菌（ETBF）菌株来限制肠道定植。我们在此表明，第二种产肠毒素菌株能够定植，这依赖于脆弱拟杆菌致病岛（BFPAI）。显示脆弱拟杆菌毒素（BFT）存在复杂环境调控的其他数据表明，毒力因子可能经过适应性改变以修饰结肠生态位，从而提供菌株特异性的定植优势。我们得出结论，需要更复杂的宿主-微生物-微生物群相互作用模型来研究这一假设。
