The Center for Biofilm Engineering
'Crabby' compound that skewers bacteria could prevent
medical implant infections
Public Press
Release, 09/10/2006
Contact: Michael Bernstein
m_bernstein@acs.org
202-872-4400 (Washington, DC)
American Chemical Society
__________________________________________
A chemical compound found in crabs and shrimp that has long
been known to have certain medicinal value also can act like a
"bed of nails," fending off microbes seeking to colonize wound
dressings, catheters and other implantable medical devices,
according to Montana State University researchers. Using the
compound to coat these medical devices, they say, could help
prevent thousands of bacterial and yeast infections annually.
The preliminary finding, by Philip Stewart, Ph.D., director of
MSU's Center for Biofilm Engineering, and Ross Carlson, Ph.D.,
assistant professor of chemical engineering, was described today
at the 232nd national meeting of the American Chemical Society,
the world's largest scientific society.
In their laboratory studies, chitosan - a sugar in the cells
of crabs and shrimp - repelled bacteria and yeast, effectively
preventing these microbes from forming slimy, glue-like layers of
infectious |
 |
Biofilms, slimy layers of
Staphylococcus epidermidis bacteria (above) and other harmful
microbes that form on catheters and other implantable medical
devices, are considered the leading cause of bacterial infections
in the United States. Coating these devices with chitosan, a
medicinal compound derived from crabs and shrimp, could prevent
thousands of infections each year, according to new research
presented at the 232nd American Chemical Society National Meeting
in San Francisco.
Credit: (Photo courtesy of Ross Carlson and Betsey Pitts, Montana
State University – Bozeman) |
cells, known as biofilms, Stewart said. These biofilms
account for up to 65 percent of the bacterial infections in the United
States, according to the Centers for Disease Control and Prevention.
The researchers say that while chitosan is well known for its
antimicrobial activity, this is the first time its anti-biofilm activity
has been described.
"Coating chitosan onto a surface seems to stop bacteria and yeast from
colonizing that surface," Stewart said. "Chitosan almost acts like a bed
of nails. If a microbe alights on it, the chitosan skewers it or causes
it to leak. That might not kill microbes outright, but it certainly
discourages them from establishing a foothold."
Biofilms are considered the leading cause of up to 400,000 cases of
catheter-related, bloodstream infections each year, Stewart said. In
addition, biofilms can arise on virtually any device implanted in the
body, including mechanical heart valves, contact lens, artificial hips
and knees, and breast implants. Once a biofilm-induced infection takes
hold, it can be difficult to treat and often requires the surgical
removal of the affected device, he said.
If further testing in animals and humans proves successful, coating
these devices with chitosan could become an important first line of
defense, according to Stewart. "I don't want to claim we've fully solved
the problem here," he said, "but … I think over the next 10 years we're
going to be seeing new technologies in the form of coatings that will
prevent or at least reduce the incidence of infection."
Chitosan is derived from chitin, the main component of crustacean
shells. It is sold commercially as a nutritional supplement and is an
FDA-approved material for staunching blood loss. Chitosan also is used
in biomaterials, as a thickener in cosmetics and a flocculating agent in
water treatment. As a biomaterial, chitosan has a track record for its
non-toxicity, biocompatibility, ability to promote healing and its
inherent antimicrobial properties.
###
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.
-- Doug Dollemore
The paper on this research, COLL 021, will be presented Sunday, Sept.
10, 8:40 a.m., in the Sir Francis Drake hotel, Windsor Room, during the
symposium, "Structure, Interactions and Reactivity at Microbial
Surfaces."
Philip S. Stewart, Ph.D., is director of the Center for Biofilm
Engineering at Montana State University in Bozeman.
Ross P. Carlson, Ph.D., is an assistant professor of
chemical engineering at Montana State University in Bozeman.
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