As Antibiotic Resistance Grows, Researchers Study How the Body Uses Copper to Fight Infection

When bacteria invade the urinary tract, the human body has an unlikely weapon among its defenses: copper. Researchers at the Texas A&M College of Veterinary Medicine and Biomedical Sciences are investigating how the body uses this essential trace mineral to fight urinary tract infections (UTIs), how bacteria manage to survive that attack, and whether the discoveries could lead to new treatments as antibiotics become harder to rely on.

The work builds on earlier findings from the lab of Dr. Sarguru Subash, an associate professor in the college's Department of Veterinary Pathobiology, showing that the body pumps copper into the urinary tract during infection to kill UTI-causing bacteria. Copper is toxic to bacteria in the right concentration, and as part of the body's early immune response, specialized immune cells expose invading bacteria to an antimicrobial mixture that includes the metal. But many bacteria have evolved ways to remove or detoxify copper they encounter in the environment, creating what Subash describes as a tug-of-war between host and pathogen.

Subash's new project will examine the interaction from both sides. Part of it will study the genetic mechanisms that let UTI-causing bacteria tolerate increased copper, and explore early evidence that copper may interfere with fimbriae, hairlike structures bacteria use to attach to the bladder lining -- an attachment that helps them resist being flushed out during urination. The researchers will also study ceruloplasmin, a copper-containing protein that may help deliver copper during a UTI, and how the body safely transports and stores the metal.

Beyond understanding the biology, Subash's team is testing whether an experimental antimicrobial compound that becomes more effective in the presence of copper could be developed into a new therapy that works alongside the immune system's existing defenses. Subash said any clinically available copper-dependent treatment is still likely years away.

While the research is focused on UTIs, some of the same bacteria that cause them can also cause infections elsewhere in the body, meaning discoveries about their response to copper could eventually inform treatments for other bacterial infections as well.