Infections in humans occur in the context of complex niches where the pathogen interacts with both the host microenvironment and immune response, and the symbiotic microbial community. The polymicrobial nature of many human infections adds a further layer of complexity. The effect of co‐ or polymicrobial infections can result in enhanced severity due to pathogens cooperative interaction or reduced morbidity because one of the pathogens affects the fitness of the other(s). In this review, the concept of co‐infections and polymicrobial interactions in the context of the intestinal mucosa is discussed, focusing on the interplay between the host, the microbiota and the pathogenic organisms. Specifically, we will examine examples of pathogen‐cooperative versus ‐antagonistic behaviour during co‐ and polymicrobial infections. We discuss: the infection‐induced modulation of the host microenvironment and immune responses; the direct modulation of the microorganism's fitness; the potentiation of inflammatory/carcinogenic conditions by polymicrobial biofilms; and the promotion of co‐infections by microbial‐induced DNA damage. Open questions in this very exciting field are also highlighted.

中文翻译：

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肠道黏膜中的共同和多种微生物感染：宿主-微生物群-病原体的观点

人类感染发生在病原体与宿主微环境和免疫反应以及共生微生物群落相互作用的复杂生态位的背景下。许多人类感染的多种微生物性质进一步增加了复杂性。由于病原体协同相互作用或降低发病率，共同或多种微生物感染的影响可能导致严重程度增加，因为其中一种病原体影响其他病原体的适应性。在这篇综述中，讨论了肠粘膜背景下的混合感染和多种微生物相互作用的概念，重点是宿主、微生物群和病原生物之间的相互作用。具体来说，我们将研究在共同和多种微生物感染期间病原体合作与拮抗行为的例子。我们讨论：感染诱导的宿主微环境和免疫反应的调节；微生物适应性的直接调节；多微生物生物膜对炎症/致癌条件的增强作用；微生物诱导的 DNA 损伤促进合并感染。这个非常令人兴奋的领域中的开放性问题也被突出显示。