Methicillin-resistant Staphylococcus
aureus (MRSA) infections are caused by a type of staph bacteria that has become
resistant to the antibiotics used to treat ordinary staph infections. The rise
of MRSA infections is limiting the treatment options for physicians and
surgeons. Now, an international team of researchers, led by Elizabeth Loboa,
dean of the University of Missouri College of Engineering, has used silver
ion-coated scaffolds, or biomaterials that are created to hold stem cells,
which slow the spread of or kill MRSA while regenerating new bone. Scientists
feel that the biodegradable and biocompatible scaffolds could be the first step
in the fight against MRSA in patients.
"Osteomyelitis is a debilitating
bone infection that can result when MRSA invades bone tissue, including bone
marrow or surrounding soft tissues," said Loboa, who also is a professor
of bioengineering. "Increasingly, those in the healthcare profession are
running out of choices when it comes to treating MRSA while regenerating
tissue. Using previously reported scaffolds that were created in our lab, we
set out to determine the efficacy of coating these structures with silver ions
and whether they were useful in treating or preventing osteomyelitis."
The scaffolds were created from a
polymer called polylactic acid (PLA), which is an FDA approved material that
eventually biodegrades in the body. Next, researchers applied a silver
ion-releasing coating to the scaffolds and "seeded" them with
fat-derived adult stem cells that could be "triggered" to create bone
cells. Researchers also seeded the scaffolds with MRSA so that they could
observe whether silver ions could fight the bacteria. The scientists found that
the silver ion-releasing scaffolds not only inhibited MRSA but also supported
bone tissue formation.
"Silver is well known for its
antimicrobial properties and is highly toxic to a wide range of microorganisms
such as MRSA," Loboa said. "Silver ions work mechanically – they
actually disrupt the cellular machinery of MRSA. Our research now has shown
that bone tissues still can be formed even in the presence of MRSA. We've
created the materials needed for bone tissue engineering that will allow
patients to use their own fat cells to create patient-specific bone and
surgically implant those cells and tissues while diminishing, or potentially
eliminating, the risk of MRSA infection."
Posted by Dr. Tim Sandle