Special Dyes and Lighting Kill MRSA, Research Shows

WEDNESDAY Sept. 10, 2008 -- A new kind of paint that releases titanium dioxide when exposed to fluorescent light and a green dye for wounds that gives off toxic molecules when activated by near-infrared light could both kill the deadly superbug known as MRSA, two new studies claim.

MRSA stands for methicillin-resistant Staphylococcus aureus. It's a strain of staph that's resistant to many antibiotics commonly used to treat it, and it can be fatal. Both reports were presented Tuesday at the Society for General Microbiology Autumn meeting at Trinity College in Dublin.

In the first study, British researcher Lucia Caballero, from Manchester Metropolitan University, found that paint that contained particles of titanium dioxide killed bacteria when it absorbed ultraviolet light.

"If this turns out, the impact is sure to be positive in the area of health," Caballero said.

The same reaction occurs when paints containing titanium dioxide are exposed to infrared light. The researchers found that the paint containing titanium dioxide successfully killed bacteria when the concentration of these nanoparticles was stronger than the normal paint. In fact, they found that all E. coli were killed with fluorescent lights.

"There are many circumstances where it is necessary or desirable to remove or to kill microorganisms found in a biological host or on surfaces," Caballero said. "Maintenance of hygienic standards is essential in hospitals, pharma and the food industry. Surface hygiene could be improved by the action of fluorescent light on catalytic surfaces, such as paints containing nanotitanium, for retarding contamination and saving on cost of cleaning maintenance."

In the second report, Dr. Ghada Omar, from University College London, found that 99 percent of the MRSA bacteria in infected wounds could be killed using a green dye that gives off toxic molecules when activated by infrared light.

"The chemicals produced when the dye is activated harm the bacteria in such a wide variety of ways that it is unlikely bacteria could ever develop resistance to the treatment," Omar said in a statement. "This makes it ideal, and possibly the only option, for treating infections with multiple drug-resistant bacteria, including MRSA."

Infected wounds are a major problem for thousands of hospital patients. Up to 9 percent of hospital-acquired infections occur during surgery and contribute to 77 percent of deaths from operations. These infections increase the length of time patients remain in hospital and increase costs, Omar noted.

Dr. Pascal James Imperato, Dean and Distinguished Service Professor of the Graduate Program in Public Health at SUNY Downstate Medical Center in Brooklyn, said a lot more work needs to be done before these technologies become practical.

"It's very much in the experimental stage at this point," Imperato said. "It's an interesting new development, but one is going to have to see many more studies to determine whether or not this is really going to work."

Dr. Marc Siegel, an associate professor of medicine at New York University School of Medicine, thinks that basic cleanliness can do more to remove the threat of hospital infections than these new technologies.

"This technology is very promising, but it gets us away from the real issue, which is that we have a problem with cleanliness and sterility in hospitals," Siegel said. "The real issue is that doctors don't change their coats, change their gloves enough. We are not using hand wipes."

Siegel noted that soap and water, when used properly, gets rid of most of this bacteria.

"MRSA has been around for 20 years and is a symptom of our inability to properly clean and sterilize facilities, while, at the same time, we are overusing antibiotics," Siegel said.

More information

For more on MRSA, visit the U.S. Centers for Disease Control and Prevention.

Posted: September 2008


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