Effects of polysaccharopeptide from Trametes versicolor and amoxicillin on the gut microbiome of healthy volunteers: A randomized clinical trial

Background Interactions between the microbial flora of the intestine and the human host play a critical role in maintaining intestinal health and in the pathophysiology of a wide variety of disorders such as antibiotic associated diarrhea, Clostridium difficile infection, and inflammatory bowel disease. Prebiotics can confer health benefits by beneficial effects on the intestinal microbiome, whereas antibiotics can disrupt the microbiome leading to diarrhea and other side effects. Aim To compare the effects of the prebiotic, polysaccharopeptide from Trametes versicolor, to those of the antibiotic, amoxicillin, on the human gut microbiome Methods Twenty-four healthy volunteers were randomized to receive PSP, amoxicillin, or no treatment (control). Stool specimens were analyzed using bTEFAP microbial ecology methods on seven occasions over 8 weeks from each participant in the active treatment groups and on three occasions for the controls. Results Twenty-two of 24 participants completed the protocol. PSP led to clear and consistent microbiome changes consistent with its activity as a prebiotic. Despite the diversity of the human microbiome we noted strong microbiome clustering among subjects. Baseline microbiomes tended to remain stable and to overshadow the treatment effects. Amoxicillin treatment caused substantial microbiome changes most notably an increase in Escherichia/Shigella. Antibiotic associated changes persisted to the end of the study, 42 days after antibiotic therapy ended. Conclusions The microbiomes of healthy individuals show substantial diversity but remain stable over time. The antibiotic amoxicillin alters the microbiome and recovery from this disruption can take several weeks. PSP from T. versicolor acts as a prebiotic to modulate human intestinal microbiome composition.