Every year, about half a million patients are infected by Clostridium difficile, an otherwise harmless bacterium that can multiply out of control when the use of antibiotics upsets the balance of microorganisms in the gut. In 2011, about 15,000 deaths were directly attributable to the infection, according to a recent study by the federal Centers for Disease Control and Prevention (CDC).
Current probiotic treatments, which promote the growth of helpful bacteria, have been ineffective against the infection, also known as C. diff.
But work being done at U.Va.’s Division of Infectious Diseases and International Health could lead to a new treatment by the end of the calendar year, according to Dr. Bill Petri, chief of the division. That’s an unusually optimistic estimate in medical research, where scientific breakthroughs predate new treatments by several years.
“Some of these advanced probiotics are actually being tested today in the clinic for their role,” Petri said. “We’re actually participating in advanced clinical trials at U.Va.”
Immunologist Erica L. Buonomo was the driving force behind the new discovery, Petri said, which has to do with the role of white blood cells in protecting against C. diff.
Buonomo found that a particular type of white blood cells, called eosinophils, act as a barrier against the infection, which breaks down the lining of the gut. These eosinophils are recruited by a protein called IL-25. A serious C. diff infection kills eosinophils, allowing the bacteria to enter the gut.
The researchers found that gut bacteria stimulate the production of IL-25, so the right probiotic could help with the production of protective eosinophils.
“We identified a pathway in the immune response that reduces the severity of an infection,” Buonomo said. “When we activate this pathway, we find mice are a lot less sick.”
The discovery would be especially helpful for elderly patients, who are most at risk. It also could have larger implications in the world of microbiology.
Eosinophils are best known for their role in allergic reactions and asthma attacks, when a high number of eosinophils cause inflammation.
The function of these cells was not entirely clear before Buonomo’s discovery. She believes this knowledge could help doctors fight other types of gastrointestinal disorders, such as irritable bowel syndrome.
U.Va. is now working on a probiotic with a Boston-based firm called Seres Therapeutics
The finished product will be tested in Charlottesville, Petri said.