Copper has its limits as antimicrobial agent as resistance grows

copperStudies show again and again what all pharmacists and microbiologists already know: Bacteria build immunity to antibiotics, pesticides and disinfectants, rendering them largely ineffective over time. Below are some studies that discuss the use of copper as an antimicrobial.

Characterization of Copper Resistance in Acinetobacter baumannii points out that Acinetobacter baumannii causes many types of severe nosocomial infections and that some isolates have acquired resistance to almost every available antibiotic, limiting treatment options. Copper is an essential nutrient, but becomes toxic at high concentrations. The inherent antimicrobial properties of copper give it potential for use in novel therapeutics against drug resistant pathogens. We show that A. baumannii clinical isolates are sensitive to copper in vitro, both in liquid and on solid metal surfaces. Since bacterial resistance to copper is mediated though mechanisms of efflux and detoxification, we identified genes encoding putative copper-related proteins in A. baumannii and showed that expression of some of these genes is regulated by copper concentration. We propose that the antimicrobial effects of copper may be beneficial to development of future therapeutics that target multidrug resistant bacteria.

Bacterial resistance to copper in the making for thousands of years suggests that genetic changes pose risks to human immunity. Published at The Ohio State University website, Misti Crane writes that more copper in the environment leads to more bacteria, including E. coli that develops a genetic resistance.

Characterization of copper-resistant bacteria and bacterial communities from copper-polluted agricultural soils of central Chile suggests that “bacterial communities of agricultural soils from central Chile exposed to long-term copper (Cu) pollution have been adapted by acquiring Cu genetic determinants. Five bacterial isolates showed high copper resistance and additional resistance to other heavy metals. Detection of copA gene in plasmids of four Cu-resistant isolates indicates that mobile genetic elements are involved in the spreading of Cu genetic determinants in polluted environments.”