So you might be wondering what copper has to do with antibiotic resistance? In agriculture, it& #39;s actually fairly common to treat livestock with copper compounds as an alternative to traditional antibiotics.

Bacteria are very clever though and have ways to remove toxic copper ions. A 3 part pump takes toxic Cu(I) ions from around the cell and exports those ions out of the cell. Another protein called CueO will covert Cu(I) to the less toxic Cu(II) form.

We tested how bacteria respond by treating the cells with increasing concentrations of copper sulfate and measured their growth over time. We found that one of our strains (in black) was more sensitive to copper treatment compared to the wild type E. coli strain (in red).