Chitosan-Coated Implants Can Prevent Infections

A new study has found that coating implants and implantable devices with chitosan--a sugar found in the cells of crabs and shrimps--can prevent implant infections.

Researchers from Montana State University (MSU, Bozeman, MT, USA) found that chitosan repelled bacteria and yeast, effectively preventing these microbes from forming biofilms--slimy, glue-like layers of infectious cells. As a biomaterial, chitosan has a track record of non-toxicity, biocompatibility, ability to promote healing, and inherent antimicrobial properties. However, this is the first time its anti-biofilm activity has been described. The study was presented at the national meeting of the American Chemical Society, held in September 2006 in San Francisco (CA, USA).

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. Biofilms are considered the leading cause of up to 65% of catheter-related bloodstream infections each year in the United States alone.

"Coating chitosan onto a surface seems to stop bacteria and yeast from colonizing that surface,” said lead author Philip Stewart, Ph.D., director of MSU's Center for Biofilm Engineering. "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.”

Chitosan is derived from chitin, the main component of crustacean shells. It is sold commercially as a nutritional supplement. Chitosan is also used to staunch blood loss, as a thickener in cosmetics, as a flocculating agent in water treatment, and is also used in biomaterials.



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