Paleo-MARE: a paleoecological approach to deciphering the impact of heavy metals on antibiotic resistance spread in the environment

Global biogeochemical cycles drive our planets health through the control of microbial habitats, nutrient availability and distribution, and exposure to reactive chemicals.

By releasing heavy metals into the environment and altering natural fluxes, Humans have carried out a planetary wide experiment for millennia that is pushing our ecosystem towards an unknown future.

More recently, this has included the production, use and release of antibiotics, which has led to the spread of antibiotic resistance genes (ARGs) across the globe.

ARG spread has critical consequences for human and environmental health with an estimated 700.000 deaths/year resulting from infections unresponsive to antibiotics. However, the underlying mechanisms that led to the spread of ARGs worldwide are unknown. The presence of heavy metal resistance genes (HMRGs) and ARGs in microbial genomes suggests a co-selection.

However, present day ecosystems are contaminated by both.

To solve this conundrum, I will combine geochemical and microbiological discovery of the links between heavy metal pollution and the spread of antimicrobial resistance from pre-industrial times to the present using paleoecological archives.

I will identify the mechanisms underlying metal-induced ARG spread, the preferential relationships between specific metals and ARGs, and quantify the timing between drug/metal use and ARG spread, determine the impact of emerging pollutants on ARG spread, and evaluate the future risk of remobilization of contaminants and resistance genes.

I will redefine how heavy metal pollution maintains antibiotic resistance in the environment.

This will reach well beyond the project and develop the synergy of microbiology and geochemical processes for a quantum-leap forward in defining the effects of geochemistry on human health.

These results will provide fundamental data that can be used to inform policy on emission guidelines and on drug development.