Despite vast sums of money being spent to combat them, hospital-acquired infections continue to afflict millions of people annually. The problem has been made worse by widespread use of antibiotics over the years, which have made hospitals breeding grounds for especially virulent bacterial strains. Often present in the air, such bacteria can contaminate sterile implantable medical devices as soon as they are removed from their packaging. Once on a device’s surface, the bacteria cells anchor themselves in place, eventually forming colonies known as biofilms that are often impervious to the body’s natural defense systems as well as aggressive antibiotic therapy.
Contaminated medical devices cause more than 50% of hospital-acquired infections, according to Jeffrey Dabkowski, a microbiology graduate researcher in microbiology at University of Massachusetts Amherst. Looking to nature to find a new weapon against infection, Dabkowski and other researchers at the university worked under the guidance of professors Gregory N. Tew and Klaus Nüsslein to develop a polymer inspired by organic compounds known as host defense peptides. Naturally found in organisms ranging from amphibians to humans, host defense peptides quickly kill bacteria and other microbes on contact and are not prone to bacterial resistance. Because the polymer developed by the university researchers is constructed from elements common to organic, living systems such as carbon, hydrogen, and nitrogen, it is expected to be well tolerated by the body. In addition, the polymer is thought to be better at targeting bacteria than silver, which has become an increasingly popular option for fighting medical-device related infections.
|S. aureus bacteria frequently cause hospital-acquired infections.|
The researchers at the university confirmed that the polymer is effective against S. aureus—a bacteria strain frequently implicated in hospital-acquired infections. After spraying a control sample and the novel polymer with a solution containing the bacteria, the surfaces of the materials were allowed to dry and the bacteria left to incubate for 15 minutes. Following that, the surfaces of the materials were studied to determine the populations of live bacteria on their surfaces. The researchers found that, while the control sample demonstrated vigorous bacterial activity, that all of the bacteria on the new polymer’s surface had been killed. Later tests showed the polymer to also be effective against E. coli bacteria. The polymer also was shown to be effective when blended at one percent weight into conventional medical polymers such as PVC, polystyrene-co-butadiene rubber, and polylactide-co-glycolide.
Although it remains unclear when the polymer will be commercially available, it seems like any addition to the arsenal of antibacterial agents would be welcome.Brian Buntz