Researchers from Australia and Loyola University Chicago Stritch School of Medicine have figured out that Toxin B produced by C. difficile is the more important toxin compared to Toxin A. “For 20 years, we have been focusing on Toxin A,” says Dale Gerding, M.D., co-author of the study. “But it turns out the real culprit is Toxin B.”
The team noted that a human clinical trial using a drug that bound Toxin A more than it bound Toxin B failed to treat C. diff effectively. They thus engineered mutant strains of the bacteria to do further testing.
“It turns out that in the strain in which Toxin A was knocked out, the organism was fully virulent,” explains Stuart Johnson, Ph.D., associate professor of medicine at Loyola University Chicago Stritch School of Medicine. When they knocked the Toxin B out in another set of experiments, the organism didn't cause disease.
These findings appear in the March 1 edition of Nature.