Aug. 17, 2010 -- Biotech scientists at Rensselaer Polytechnic Institute have developed a coating for use in health care settings that they say kills the deadly MRSA germ.
MRSA, or methicillin-resistant Staphyloccus aureus, is a virulent bacterium that causes antibiotic-resistant infections, killing about 90,000 patients a year. Because it has been hard to battle, it is sometimes called a “superbug.”
But Rensselaer scientists say their coating, for use on surgical equipment, hospital walls, and other surfaces in health care settings, seems to be very effective in eradicating MRSA.
The study is published in ACS Nano, a journal of the American Chemical Society.
In tests, 100% of MRSA bacteria were killed within 20 minutes of contact with a surface painted with latex paint laced with the coating, the researchers say. The coating is made with lysostaphin, a naturally occurring enzyme, combined with carbon nanotubes.
“We’re building on nature,” Jonathan S. Dordick, PhD, director of Rensselaer’s Center for Biotechnology and Interdisciplinary Studies, says in a news release. “Here we have a system where the surface contains an enzyme that is safe to handle, doesn’t appear to lead to resistance, doesn’t leach into the environment, and doesn’t clog up with cell debris.”
When the superbugs came in contact with a painted surface, “they’re killed,” he says.
How It Works
Lysostaphin works by attaching itself to the bacterial cell wall, slicing it open, but is not toxic to human cells, Dordick says.
Researcher Ravi S. Kane, PhD, says the enzyme is attached to the carbon nanotube with a short, flexible polymer link, improving its ability to reach the MRSA bacteria.
“The more the lysostaphin is able to move around, the more it is able to function,” Dordick says.
Kane and Dordick worked With Dennis W. Metzger, PhD, and Ravi Pangule, a graduate student in chemical engineering, at Albany Medical College, where Metzger maintains strains of MRSA.
“At the end of the day, we have a very selective agent that can be used in a wide range of environments -- paints, coating, medical instruments, doorknobs, surgical masks -- and it’s active and it’s stable,” Kane says. “It’s ready to use when you’re ready to use it.”
They say their approach will likely prove superior to previous attempts at creating antimicrobial agents, some of which release biocides, which can lose effectiveness over time due to leaching into the environment and may have harmful side effects, the researchers say.
"We spent quite a bit of time demonstrating that the enzyme did not come out of the paint during antibacterial experiments,” he says. “Indeed, it was surprising that the enzyme worked as well as it did while remaining embedded near the surface of the paint.”
It’s unlikely, Kane says, that MRSA superbugs will develop resistance to a naturally occurring enzyme, which has “evolved over hundreds of millions of years to be very difficult for Staphyloccus aureus to resist.”
They also say their new coating can be washed repeatedly without losing effectiveness and that it has a dry storage shelf life of up to six months.
MRSA can infect the bloodstream, the lungs, and the urinary tract, and people can carry it without being sickened. Killing it on surfaces is important because MRSA is spread by contact and can be carried by people who touch infected objects.