The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
The Jackson Laboratory, Bar Harbor, ME, USA.
ISME J. 2019 Mar;13(3):805-823. doi: 10.1038/s41396-018-0312-9. Epub 2018 Nov 15.
Mammalian hosts constantly interact with diverse exogenous microbes, but only a subset of the microbes manage to colonize due to selective colonization resistance exerted by host genetic factors as well as the native microbiota of the host. An important question in microbial ecology and medical science is if such colonization resistance can discriminate closely related microbial species, or even closely related strains of the same species. Using human-mouse fecal microbiota transplantation and metagenomic shotgun sequencing, we reconstructed colonization patterns of human fecal microbes in mice with different genotypes (C57BL6/J vs. NSG) and with or without an intact gut microbiota. We found that mouse genotypes and the native mouse gut microbiota both exerted different selective pressures on exogenous colonizers: human fecal Bacteroides successfully established in the mice gut, however, different species of Bacteroides selectively enriched under different gut conditions, potentially due to a multitude of functional differences, ranging from versatility in nutrient acquisition to stress responses. Additionally, different clades of Bacteroides cellulosilyticus strains were selectively enriched in different gut conditions, suggesting that the fitness of conspecific microbial strains in a novel host environment could differ.
哺乳动物宿主与各种外源微生物不断相互作用，但由于宿主遗传因素以及宿主固有微生物群落施加的选择性定植抗性，只有一部分微生物能够定植。微生物生态学和医学领域的一个重要问题是，这种定植抗性是否可以区分密切相关的微生物物种，甚至是同一物种的密切相关菌株。使用人-鼠粪便微生物群移植和宏基因组鸟枪法测序，我们重建了具有不同基因型（C57BL6/J 与 NSG）和/或完整肠道微生物群的小鼠中人类粪便微生物的定植模式。我们发现，小鼠基因型和固有小鼠肠道微生物群都对外源定植体施加了不同的选择压力：人粪便拟杆菌成功定植在小鼠肠道中，但不同物种的拟杆菌在不同的肠道条件下选择性富集，这可能是由于多种功能差异所致，从获取营养的多功能性到应激反应。此外，不同的纤维分解拟杆菌菌株分支在不同的肠道条件下选择性富集，这表明同种微生物菌株在新的宿主环境中的适应性可能不同。
