Stress and the microbiome: linking glucocorticoids to bacterial community dynamics in wild red squirrels

Bacterial diversity within animals is emerging as an essential component of health, but it is unknown how stress may influence the microbiome. We quantify a proximate link between the oral microbiome and hypothalamic–pituitary–adrenal (HPA) axis activity using faecal glucocorticoid metabolites (FGM) in wild red squirrels (Tamiasciurus hudsonicus). Not only was bacterial diversity lower at higher levels of FGM, but also between capture periods a change in bacterial relative abundance was related to an increase in FGM. These linkages between the HPA axis and microbiome communities represent a powerful capacity for stress to have multi-dimensional effects on health.

动物体内的细菌多样性正逐渐成为影响宿主健康的关键要素，但目前尚不明确压力如何作用于宿主微生物组。本研究以野生北美红松鼠（Tamiasciurus hudsonicus）为研究对象，通过粪便糖皮质激素代谢物（FGM）量化了口腔微生物组与下丘脑-垂体-肾上腺（HPA）轴活性之间的直接关联。研究发现，不仅细菌多样性随FGM水平升高而降低，且两次捕获期间细菌相对丰度的变化也与FGM水平的升高显著相关。下丘脑-垂体-肾上腺轴与微生物组群落之间的这些关联，表明压力可通过多种途径对宿主健康产生多维影响。