The process by which selection pressure from one agent (e.g., a heavy metal) simultaneously selects for resistance to another agent (e.g., an antibiotic) because the resistance determinants are genetically linked — typically on the same mobile genetic element (plasmid, transposon, integron).
Mechanisms
- Co-resistance: Distinct resistance genes for different agents on the same genetic element (e.g., a plasmid carrying both a mercury reductase and a beta-lactamase).
- Cross-resistance: A single mechanism confers resistance to both agents (e.g., efflux pumps that export both metals and antibiotics).
- Co-regulatory: A single regulatory system controls expression of resistance to both agents.
Relevance to This Wiki
- Heavy metal contamination in the environment (arsenic, mercury, cadmium, lead, copper, zinc) drives co-selection for antibiotic resistance in gut and environmental microbiomes.
- Metal-antibiotic co-resistance is documented in staphylococcus aureus (MRSA), escherichia coli, pseudomonas aeruginosa, and klebsiella pneumoniae.
- Agricultural and industrial metal pollution creates reservoirs of co-selected resistance genes that enter the human gut metal microbiome.
Connections
- dysbiosis — co-selected resistant organisms may dominate dysbiotic communities
- nutritional immunity — host metal sequestration could inadvertently select for co-resistant strains
- gut metal microbiome — the primary site where metal-driven co-selection affects human health