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

Introduction

Global biogeochemical cycles drive our planet’s 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.

Antibiotic Resistance Genes

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 per year resulting from infections unresponsive to antibiotics. However, the underlying mechanisms that led to the spread of ARGs worldwide are unknown.

Co-selection of Resistance Genes

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.

Research Objectives

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.

Specific Goals

1. Identify the mechanisms underlying metal-induced ARG spread.
2. Determine the preferential relationships between specific metals and ARGs.
3. Quantify the timing between drug/metal use and ARG spread.
4. Assess the impact of emerging pollutants on ARG spread.
5. Evaluate the future risk of remobilization of contaminants and resistance genes.

Impact of Research

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.

Policy Implications

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