French clay that kills several kinds of disease-causing bacteria is at the forefront of new research into age-old, nearly forgotten, but surprisingly potent cures. Among the malevolent bacteria that a French clay has been shown to fight is a "flesh-eating" bug (M. ulcerans) on the rise in Africa and the germ called MRSA, which was blamed for the recent deaths of two children in Virginia and Mississippi.
"There are very compelling reports of clay treating infections, but that's anecdotal evidence, not science," said Lynda Williams, an associate research professor in the School of Earth and Space Exploration at Arizona State University, Tempe. Williams is coordinating three teams of U.S. researchers (at ASU, USGS, and SUNY-Buffalo) studying healing clays under a two-year, $440,000 grant from the National Institutes of Health-National Center for Complementary and Alternative Medicine. Her ASU colleague Shelley Haydel is lending her expertise in clinical medicine to perform the microbiological research.
For thousands of years, people have used clay to heal wounds, soothe indigestion, and kill intestinal worms. Though the practice has declined in modern times, the recent rise of drug-resistant germs has scientists looking more closely at these ancient remedies to learn exactly what they can do and how they do it.
Rossman Giese, Ph.D., professor of geology in UB's College of Arts and Sciences, and Tracy Bank, Ph.D., assistant professor of geology at UB, are using several techniques to study the clays, including atomic force microscopy. The researchers are studying the weak interactions that are responsible for the stickiness of clay particles.
"We look at the attraction or repulsion between natural and modified clays and bacteria," said Giese.
Unlike antibiotics, which are essentially a chemical weapon against bacteria, antimicrobial clays kill through purely physical means, he explained. "The bacterium has to come into physical contact with the clay in order for something to happen." Giese said. That contact turns deadly.
"The antimicrobial agents in the clay poke a hole in the cell wall of the bacterium causing the bacterium to leak to death," he explained. "The nice thing about that is that there is no way that the bacterium can evolve to avoid it, so resistance to the antimicrobial clay is unlikely to become a problem."
The clay developed by UB researchers has been very effective in lab testing.
"Our studies show that when we mix a bit of our modified clay at very low levels into sewage sludge that contains all kinds of bacteria, the modified clay kills everything," said Giese. "Nothing will grow in it."
"We're beginning to generate the first scientific evidence of why some minerals might kill bacterial organisms and others might not," said Williams.
In laboratory tests at ASU's Biodesign Institute, co-PI Haydel, an assistant professor in the School of Life Sciences, showed that one clay killed bacteria responsible for many human illnesses, including: Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), penicillin-resistant S. aureus (PRSA), and pathogenic Escherichia coli (E. coli).
It also killed Mycobacterium ulcerans, a germ related to leprosy and tuberculosis that causes the flesh-eating disease Buruli ulcer. This effect was first described in 2002, by Line Brunet de Courssou, a French humanitarian working in the Ivory Coast, Africa, who cured Buruli ulcers with daily applications of French clay she knew from childhood. Currently, advanced cases of Buruli ulcer can only be cured by surgical excision or amputation.
The new medicinal clay research will be presented on Monday, 29 October 2007, at the Geological Society of America Annual Meeting in Denver.
In the same session there will be a related presentation describing the work 100 years ago of Julius Stumpf, a German physician and scientist who used white clay from Germany to treat a deadly form of Asian cholera; diphtheria; gangrene; ulcers of the tibia (a bone between the knee and foot); and the skin disease eczema.
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