The microbiota—the diverse set of commensal microbes that normally colonize humans—represents the first line of defense against infectious diseases. In this review, we summarize the direct and indirect mechanisms by which the microbiota modulates susceptibility to, and severity of, infections, with a focus on immunological mechanisms. Moreover, we highlight some of the ways that modern-world lifestyles have influenced the structure-function relationship between the microbiota and infectious diseases. Ultimately, understanding how the microbiota influences infectious risks will facilitate development of microbiota-derived therapeutics that bolster host defenses.

中文翻译：

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宿主-微生物群-病原体相互作用的现代世界观

微生物群——通常在人类中定居的多种共生微生物——代表了抵御传染病的第一道防线。在这篇综述中，我们总结了微生物群调节感染易感性和严重程度的直接和间接机制，重点是免疫机制。此外，我们强调了现代世界生活方式影响微生物群与传染病之间结构-功能关系的一些方式。最终，了解微生物群如何影响感染风险将促进微生物群衍生疗法的开发，以增强宿主的防御能力。