Exploring the Therapeutic Potential of Copper Against Bacteria

A researcher at the University of Arizona College of Medicine in Tucson was awarded a $1.9 million grant by the National Institutes of Health to carry out more research on the mysteries of copper, particularly how it can be used to eradicate dangerous bacteria and other microorganisms.

We started using copper tens of thousands of years ago to cut down on bacterial infections. People used to store their food in copper pots, which helped cut down on spoilage. Copper doorknobs have been shown to cut down on hospital-acquired infections. We’re still finding more things it can do.”

Michael D.L. Johnson, Ph.D, Associate Professor, Immunobiology, University of Arizona College of Medicine

Dr. Johnson expressed his aspiration that one of these innovative applications could serve as the foundation for the development of a next-generation antibiotic. However, his research laboratory prioritizes a deeper understanding of the underlying mechanisms that render copper toxic to bacterial cells.

This fundamental knowledge will serve as a robust foundation for subsequent pharmaceutical research endeavors. The study is being supported by an R35 grant, a prestigious award specifically reserved for scientists with exceptional research track records and the demonstrated potential to advance their respective fields of study significantly.

Johnson's team will use Streptococcus pneumoniae as a model organism to try to figure out what makes bacterial cells susceptible to copper.

It’s a pretty prominent pathogen. More than a million people die per year because of these bacteria, referring to the bacteria that can cause infections in the lungs, brain, nose, and blood. Our laboratory is interested in trying to figure out how it ticks. Our way of doing that is to understand how it gets its nutrition.”

Michael D.L. Johnson, Ph.D, Associate Professor, Immunobiology, University of Arizona College of Medicine

The human body uses minerals, like calcium and iron, from the diet to maintain internal functions. Similar to other organisms, bacteria require minerals to survive; however, copper, which is necessary for human nutrition, can be harmful to bacteria.

Johnson says, “There are certain minerals that bacteria don’t want in excess, and that’s where copper comes into play. There are a lot of ways we can weaponize copper. We’re trying to study how our body uses copper as a mechanism to kill pathogens.”

Johnson thinks scientists might be able to fool bacteria into producing necessary proteins using the incorrect materials if they expose them to an excessive amount of copper.

“Copper can displace iron, manganese or other metals and inactivate the protein. It would be like me trying to start my wife’s car with my key. It doesn’t work,” said Johnson.

Johnson will supplement parallel studies conducted in the lab to gain more insight into copper's antimicrobial properties and expand on earlier research on the reaction of S. pneumoniae to copper. To make inferences about related bacteria, he stated that his objective is to determine the precise mechanism by which copper is toxic to S. pneumoniae.

“All bacteria are different, but there are some mission-critical systems that are the same from bacteria to bacteria. How they process some of these metals is almost identical,” he said. “What I’m studying can be applied to other bacteria, but first we need to understand the basic mechanism of how these things work,” said Johnson.

Johnson stated that although the development and approval of new antibiotics is slow, pathogens are becoming more resistant to them, which means that infections that were previously treatable with medication may eventually become fatal once more. Drug-resistant S. pneumoniae is categorized as a "serious threat" by the Centers for Disease Control and Prevention, which views antibiotic resistance as a threat to public health.

“Bacteria are quite crafty. They will mutate to overcome antibiotics. Our bodies have evolved to use copper to kill bacteria, and to this day, copper is still toxic. We want to take advantage of that to help people with life-threatening infections,” said Johnson.

This study is funded by the National Institute of General Medical Sciences, a branch of the National Institutes of Health.