Metagenomics. The Gut Heavy Metal and Antibiotic Resistome of Humans living in the High Arctic

Abstract Background The human microbiome plays an important role in the metabolism of xenobiotics but there are limited studies on the impacts of heavy metals on the human gut microbiome. The diet of Inughuit, indigenous community in North Greenland, includes local foods that contain high concentrations of heavy metals. Methods Four Inughuit participants from North Greenland, collected fecal samples monthly for 15 months (n=55) for mercury, lead and cadmium-concentration measurements as well as 16S rRNA gene amplicon, metagenome and metatranscriptome sequencing. Results The results show no significant effect of heavy metals at the overall ecological level. Through the assembly of a high number of near-complete metagenome-assembled genomes we observed an almost complete overlap between heavy metal resistant strains and antibiotic resistant strains, showing a strong tendency for co-resistance. Finally, we identified a colonization event with a mercury-resistant allochthonous bacterial strain with the capacity to reduce the toxicity of Hg. Keywords heavy metal resistance, antibiotic resistance, mercury resistance, co-resistance, Arctic diet, metagenome-assembled genome