Humans have known for centuries that copper is a potent weapon against infection. New research shows that the bacteria that cause serious urinary tract infections "know" this, too, and steal copper to prevent the metal from being used against them.
Blocking this thievery with a drug may significantly improve patients' chances of fighting off infections, according to researchers at Washington University School of Medicine in St. Louis. The findings appear online July 8 in Nature Chemical Biology.
In the United States alone, annual treatment costs for urinary tract infections are estimated to run as high as $1.6 billion. Most urinary tract infections are caused by Escherichia coli (E. coli).
"While some patients are able to clear these infections without issue, in others the infection persists or recurs despite antibiotic therapy," says senior author Jeff Henderson, MD, PhD, assistant professor of medicine and of molecular microbiology. "In some cases, the infection spreads to the kidney or the blood and becomes life-threatening. We've been investigating what's different about the bacteria that cause these more troublesome infections."
Scientists have known for years that E. coli makes a molecule called yersiniabactin that takes iron from host cells. The bacteria need the iron to grow and reproduce.
In earlier research, Henderson found that the E. coli that cause serious infections are more likely to make yersiniabactin. This finding and the fact that E. coli already produce another molecule that steals iron led Henderson and Kaveri Chaturvedi, a student in his laboratory, to suspect that the bacterium might be using yersiniabactin for other purposes.
To test the theory, the researchers put yersiniabactin in urine samples from healthy patients. They found the molecule bound iron as expected but also picked up copper. Next, they conducted the same analysis in samples from patients with urinary tract i
|Contact: Michael C. Purdy|
Washington University School of Medicine