Write your abstract here.How Do You Stop Flesh-Eating
Bacteria ? Apply Some Clay.
French
green clay worked
in the wilds of Africa''s Ivory Coast—and now is
proving its worth in the lab—as an effective treatment for dangerous
bacteria Image: ©ISTOCKPHOTO.COM
ANTIBACTERIAL CLAY:
Researchers have discovered several clays that kill—or prevent from growing—bacteria, including antibiotic-resistant strains.
In the 1990s French humanitarian Line Brunet de Courssou began treating Buruli ulcer—violent, flesh-eating eruptions of Mycobacterium ulcerans—with
two imported French green clays. The application of one type of clay to
such lesions produced a pain that some patients equated to childbirth
and, after several days, purplish skin tissue surrounding the open
wound. A subsequent application of a second variety, this one mixed
with shea butter (a fat), produced no pain and helped heal the oozing
wound, replacing it with flexible scar tissue over the course of
several months.
For centuries the French have used such green clays, rich in iron,
for healing wounds. And the clays have proved capable of treating these
M. ulcerans outbreaks, for which the only other cure is
surgical removal or amputation. But scientific proof was lacking, so
Brunet de Courssou enlisted the aid of mineralogist Lynda Williams of
Arizona State University (A.S.U.) in Tempe to take pictures of the
microscopic structure of the clays and try to figure out the source of
their healing powers.Williams says the clay''s antibacterial effect appears to be chemical
rather than physical, because its strength diminishes as it loses
positively charged molecules and it does not smother the bacteria or
cause its cell walls to burst. "After six hours, you can see a
surface that is kind of wormy or grainy," Williams
says. "It doesn''t look like something is precipitating at the surface.
Maybe something is going into the cell and damaging it that way."
It is also possible that the clay, which is, after all, a mix of
many different elements in a malleable mass, combines several different
properties to fight bacterial infection. "Is it a couple of things
acting synergistically?" Haydel asks. "We just don''t know."
Adds Williams: "I think these clays are
buffering water to keep whatever''s toxic to bacteria in there. If we
remove the clay from water, I think it''s not going to work."
The original batch of clay has already lost its curative power. "We
went back and got some from the same batch and it didn''t kill,"
Williams says. "This clay has been sitting outside in a pile for 10
years. It could have oxidized and maybe the oxidation state has
affected the antibacterial properties."
Many more years of research will be required to determine what, if
anything, gives the clay its ability to curb bacteria, and the
researchers have yet to publish their results in a peer-reviewed
journal. But they say there''s clearly something to the ancient remedy:
Two other clays with similar properties have already been identified.
"They''re all different mineralogically, though they have a general
structure in common," Williams says. "We''re trying to compare the
properties of these antibacterial clays and see what''s going on."
In the meantime, the clay treatment continues to be the only one available for flesh-dissolving M. ulcerans
infections in Africa, a disease the World Health Organization has
identified as an emerging health threat. And it is possible that the
clays simply prompt the human immune system to respond to the
infection, a response M. ulcerans normally suppresses.
Even sprove more useful than previously
thought. "Even if you removed the antibacterial properties, do the
clays have any effect on wound healing? What is the body''s response?
Are you stimulating tissue regeneration?" Haydel asks. "We already use
maggots and leeches in hospitals. Why don''t we use clays?"