Iron is essential for both microorganisms and their hosts. Although effects of dietary iron on gut microbiota have been described, the effect of systemic iron administration has yet to be explored. Here, we show that dietary iron, intravenous iron administration, and chronic transfusion in mice increase the availability of iron in the gut. These iron interventions have consistent and reproducible effects on the murine gut microbiota; specifically, relative abundance of the Parabacteroides and Lactobacillus genera negatively correlate with increased iron stores, whereas members of the Clostridia class positively correlate with iron stores regardless of the route of iron administration. Iron levels also affected microbial metabolites, in general, and indoles, in particular, circulating in host plasma and in stool pellets. Taken together, these results suggest that by shifting the balance of the microbiota, clinical interventions that affect iron status have the potential to alter biologically relevant microbial metabolites in the host.

铁对于微生物及其宿主都是必需的。尽管膳食铁对肠道微生物群的影响已经被描述，但全身铁给药的影响仍有待探索。在这里，我们表明，小鼠的膳食铁、静脉注射铁剂和长期输血可增加肠道中铁的利用率。这些铁干预措施对小鼠肠道微生物群具有一致且可重复的影响；具体而言，副杆菌属和乳杆菌属的相对丰度与铁储存量的增加呈负相关，而梭状芽胞杆菌属的成员与铁储存量呈正相关，无论铁的给药途径如何。一般来说，铁水平也会影响宿主血浆和粪便颗粒中循环的微生物代谢物，特别是吲哚。综上所述，这些结果表明，通过改变微生物群的平衡，影响铁状态的临床干预措施有可能改变宿主体内生物学相关的微生物代谢物。