Intestinal helminths reverse gut dysbiosis induced by urbanization: case study in a small rodent

对采自城市公园和国家森林的三种啮齿动物184只(小肠、盲肠、结肠和直肠)的肠道菌群进行了分析。我发现这两种类型的栖息地的微生物群落不同，城市红曲霉可能正在经历生态失调(即不健康的肠道微生物区系)。特别是，城市红色分枝杆菌在下胃肠道中蕴藏着更多潜在致病的幽门螺杆菌。通过使用稳定同位素分析它们的饮食习性，我发现与它们的天然同种相比，城市大黄鼠的食物生态位有所扩大。此外，根据它们的生活史，这两个物种在城市栖息地的饮食结构都发生了变化，大斑潜蝇摄取了更多的动物蛋白，红斑潜蝇摄取了更多的C3植物。这种饮食变化部分解释了观察到的肠道微生物区系的变化。最后，我发现蠕虫可能会通过促进益生菌物种的发展来帮助保护城市动物免受生物失调的影响，比如丁里卡菌。

I analyzed the gut microbiota in four regions (i.e. small intestine, cecum, colon, and rectum) along the digestive tract of 184 rodents comprised of three species (i.e. Apodemus speciosus, A. argenteus, and Myodes rufocanus) collected from urban parks and the national forest. I found that the microbial community differed between the two types of habitat and that urban M. rufocanus may be experiencing dysbiosis (i.e. unhealthy gut microbiota). In particular, urban M. rufocanus is harboring higher abundances of potentially pathogenic Helicobacter in the lower gastro intestinal tract. By analyzing their dietary habits using stable isotope analysis, I found that urban A. speciosus exhibited an expanded dietary niche as compared to their natural conspecifics. Furthermore, both species have undergone a dietary shift within the urban habitat in accordance with their life history with A. speciosus consuming more animal protein and M. rufocanus more C3 plants. This dietary shift partially explains the observed changes in the gut microbiota. Lastly, I found that helminths may help protect urban animals from dysbiosis through the promotion of probiotic bacterial species such as Butyricicoccus.