Human Health and Urban Microbiome: the Heritage of a Long Evolutionary Alliance

Urban environments have progressively become our new natural habitats, and modernization’s impact has triggered ecological shifts affecting organisms from the micro to the macro scale and their interaction networks. As a domino, the alarming reduction in microbial biodiversity resulted in human health repercussions. We coevolved shaping our immune system to the high exposure to pathogens and microorganisms our past rural lifestyle entailed. The evolutionary mismatch between our slow-adapting immunity and the abrupt disappearance of microbial species resulted in unpredicted “diseases of civilization”. Exposure to microorganisms, especially during early development, is fundamental to modulating our immune system and building up a diverse and beneficial microbiota. Safeguarding microbial diversity is urgent, yet there is little consensus on actions to restore biodiversity. Our project, titled UniBiome, is a collaborative endeavor between scientists and students, intended to characterize the salubrity of two Italian universities from a microbial perspective. As part of the MUSA initiative (Multilayered Urban Sustainability Action funded by the European Union NextGenerationEU under the NRRP), the project is structured in two seasons, each entailing more than 160 volunteer students who contributed with skin and gut microbiome samples and the collection of 520 environmental samples. Samples have been processed to extract the DNA, and the V3-V4 regions of the microbial 16S gene have been sequenced. The results chart the intricate interplay between students’ and urban microbiomes providing a new evolutionary perspective. This comprehensive mapping will inspire science-based and microbiome-oriented interventions that can harmonize urban renovation with human and environmental health.