Mud may be coming to a medicine cabinet or pharmacy near you.
Scientists in Arizona report that minerals from clay could form the
basis of a new generation of inexpensive, highly-effective
antimicrobials for fighting MRSA infections that are moving out of
health care settings and into the community. These
“superbugs” are increasingly resistant to multiple
antibiotics and cause thousands of deaths each year.

Minerals from clay could provide a source of powerful antimicrobials for fighting deadly MRSA infections and other diseases. Credot: Arizona State University, John C. Phillips.
Unlike conventional antibiotics that are often administered by
injection or pills, the so-called “healing clays”
could be used as rub-on creams or ointments to keep MRSA infections
from spreading, the researchers say. The clays also show promise
against a wide range of other harmful bacteria, including those that
cause skin infections and food poisoning, the scientists add. Their
study, one of the first to explore the antimicrobial activity of
natural clays in detail, was presented today at the 235th national
meeting of the American
Chemical Society.
Clays have been used for thousands of years as a remedy for
infected wounds, indigestion, and other health problems, either by
applying clay to the skin or eating it. Today, clays are commonly used
at health spas in the form of mud baths and facials. Armed with new
investigative tools, researchers are beginning to explore their health
claims scientifically.
“Clays are little chemical drug-stores in a
packet,” said study co-leader Lynda Williams, Ph.D., a
geochemist at Arizona State University in Tempe. “They
contain literally hundreds of elements. Some of these compounds are
beneficial but others aren’t. Our goal is to find out what
nature is doing and see if we can find a better way to kill harmful
bacteria.”
In the new study, funded by the National Institutes of Health,
Willams and her colleagues collected more than 20 different clay
samples from around the world to investigate their antibacterial
activities. In collaboration with study co-leader Shelley Haydel,
Ph.D., a microbiologist with Arizona State, the researchers tested each
of the clays against several different bacteria known to cause human
diseases. These bacteria include MRSA (methicillin-resistant
Staphylococcus aureus), Mycobacterium ulcerans (a microbe related to
the tuberculosis bacterium that causes a flesh-eating disease known as
Buruli ulcer), as well as E. coli and Salmonella (which cause food
poisoning). The researchers identified at least three clays that killed
or significantly reduced the growth of these bacteria.
The researchers are working to identify the specific compounds
in the clays that may be responsible for its antibacterial activity.
Using electron and ion microscopy, the researchers are also exploring
how these antibacterial clays interact with the cell membranes of the
bacteria in order to find out how they kill.
Williams and Haydel are continuing to test new clay samples
from around the world to determine their germ-fighting potential. They
hope that the more promising clays will be developed into a skin
ointment or pill to fight a variety of bacterial infections or possibly
as an agricultural wash to prevent food poisoning. Several companies
have expressed interest in forming partnerships to develop the clays as
antimicrobial agents, the scientists say.
But ordinary mud can contain dangerous bacteria as well as
toxic minerals like arsenic and mercury, the researchers point out.
Until healing clays are developed that are scientifically proven, which
could take several years, handwashing and other proper hygiene
techniques may be your best bet for keeping MRSA and other harmful
bacteria at bay, they say.
The American Chemical Society - the world’s largest
scientific society - is a nonprofit organization chartered by the U.S.
Congress and a global leader in providing access to chemistry-related
research through its multiple databases, peer-reviewed journals and
scientific conferences. Its main offices are in Washington, D.C., and
Columbus, Ohio.