Food-grade cationic antimicrobial ε-polylysine transiently alters the gut microbial community and predicted metagenome function in CD-1 mice

Food science: Food additives affect gut commensal bacteria Despite the trend of 'going green', in modern societies food additives are inadvertently ingested by us on a daily basis. While these additives have all been tested for the lack of direct harm, whether they may indirectly affect our health is unclear. In the gut, a complex mixture of bacteria is finely maintained to promote beneficial immunity. Using mouse as a model, the team led by David Sela at University of Massachusetts studies shows that an anti-microbial food additive, cationic homopolymer epsilon-polylysine, that is meant for thwarting bacteria in packed food, can also alter the 'balance' of gut bacteria, and, interestingly, does so in a gender-independent manner. These findings pave the road for further studies associating food additives, gut bacteria and immune-related diseases. Diet is an important factor influencing the composition and function of the gut microbiome, but the effect of antimicrobial agents present within foods is currently not understood. In this study, we investigated the effect of the food-grade cationic antimicrobial epsilon-polylysine on the gut microbiome structure and predicted metagenomic function in a mouse model. The relative abundances of predominant phyla and genera, as well as the overall community structure, were perturbed in response to the incorporation of dietary epsilon-polylysine. Unexpectedly, this modification to the gut microbiome was experienced transiently and resolved to the initial basal composition at the final sampling point. In addition, a differential non-random assembly was observed in the microbiomes characterized from male and female co-housed animals, although their perturbation trajectories in response to diet remain consistent. In conclusion, antimicrobial epsilon-polylysine incorporated into food systems transiently alters gut microbial communities in mice, as well as their predicted function. This indicates a dynamic but resilient microbiome that adapts to microbial-active dietary components.