A common bacteria found in soil has been detected in humans for the first time, leading scientists to believe it may trigger multiple sclerosis (MS), a chronic autoimmune disease. It also gives them hope for finding a new treatment or even a cure for MS.
Researchers at Weill Cornell Medical College and The Rockefeller University were the first to identify the bacterium, Clostridium C. perfringen Type B, in humans. Their study is published online in PLoS ONE.
“This bacterium produces a toxin that we normally think humans never encounter. That we identified this bacterium in a human is important enough, but the fact that it is present in MS patients is truly significant because the toxin targets the exact tissues damaged during the acute MS disease process,” says the study’s first author and senior investigator, K. Rashid Rumah, an MD/PhD student at Weill Cornell Medical College.
MS is a chronic disease which attacks the body’s central nervous system and is characterized by the destruction of myelin, the membrane that protects nerves in the brain and spinal cord. Once damaged, it inhibits the nerves’ ability to transmit electrical impulses, causing cognitive impairment and poor mobility.
The scientists say their study is small and must be expanded before a definitive connection between the bacteria and MS can be made, but they also say their findings are so intriguing that they have already begun to work on new treatments for the disease.
“While it is clear that new MS disease activity requires an environmental trigger, the identity of this trigger has eluded the MS scientific community for decades,” said Dr. Timothy Vartanian, professor of neurology and neuroscience at Weill Cornell Medical College and director of the Judith Jaffe Multiple Sclerosis Center at New York-Presbyterian Hospital/Weill Cornell Medical Center.
“Work is underway to test our hypothesis that the environmental trigger for MS lays within the microbiome, the ecosystem of bacteria that populates the gastrointestinal tract and other body habitats of MS patients.”
Scientists first discovered Clostridium C. perfringens type B in a 21-year-old woman who was experiencing a flare-up of her MS.
Clostrodium perfringens is one of the most common bacteria worldwide. The bacterium is divided into five types, A to E. Type A is commonly found in the human gastrointestinal tract and is thought to be harmless.
Types B and D carry a gene that emits a potent epsilon toxin in the intestines of grazing animals. Once in the bloodstream, that toxin causes damage to brain blood vessels and myelin, resulting in symptoms similar to that of MS in humans.
While the D subtype has only been found in two people, the B subtype had never before been found in humans.
Nevertheless, researchers wanted to see if Types B or D were associated with MS. They tested banked blood and spinal fluid from MS patients for antibody reactivity to the epsilon toxin. They found that levels of epsilon toxin antibodies in MS patients were 10 times higher than people without MS.
The team also examined stool samples from MS patients and found the A subtype in 23% of the samples, compared to 52% of the stool samples of people without MS.
“This is important because it is believed that the type A bacterium competes with the other subtypes for resources, so that makes it potentially protective against being colonized by epsilon toxin secreting subtypes and developing MS,” the researchers said.
During their studies the researchers discovered the type B bacterium in the patient who was experiencing a flare-up of MS.
“This bacterium produces a toxin that we normally think humans never encounter. That we identified this bacterium in a human is important enough, but the fact that it is present in MS patients is truly significant because the toxin targets the exact tissues damaged during the acute MS disease process,” they said.
Researchers don’t know how humans are infected with Clostridium C. perfringen Type B or D, but they are studying potential routes of exposure. They’re are also in the first stages of investigating potential treatments against the pathogen.
A vaccine for humans is possible — there is already such a vaccine for farm animals, but it requires repeat immunizations.
“But one of my favorite approaches is development of a probiotic cocktail that delivers bacteria that compete with, and destroy, Clostridium C. perfringen types B and D,” Vartanian says. “It would be such a beautiful and natural way to treat the gastrointestinal system and solve the problem.”
An estimated 400,000 Americans suffer from MS; more than two million people worldwide.
The most common form of the disease, relapsing-remitting multiple sclerosis, is characterized by episodes of worsening neurologic function followed by periods of remission involving partial or complete recovery. Symptoms may be mild or severe, ranging from numbness in the limbs to paralysis or loss of vision.
There is no cure for MS; the only therapies currently available are ones that modify its symptoms.