Light Wave Kills Hospital Superbugs, Harmless to People

GLASGOW, Scotland, November 16, 2010 (ENS) – A pioneering lighting system that kills the superbugs breeding in hospitals has been developed by researchers at the University of Strathclyde in Glasgow. The LED technology, which can be used with or instead of conventional lighting, decontaminates the air and exposed surfaces by bathing them in a narrow spectrum of visible-light wavelengths, known as HINS-light.

Two years of clinical trials just completed at Glasgow Royal Infirmary show the high-intensity light is effective against some of the most virulent pathogens found in hospitals and nursing homes, such as meticillin-resistant Staphylococcus aureus, MRSA, and Clostridium difficile.

The clinical trials have shown that the HINS-light Environmental Decontamination System provides around 60 percent greater reductions of bacterial pathogens in the hospital environment than are achieved by cleaning and disinfection alone.

“The pervasive nature of light permits the treatment of air and all visible surfaces, regardless of accessibility, either through direct or reflected exposure to HINS-light within the treated environment,” said Professor Scott MacGregor, dean of the Faculty of Engineering at Strathclyde and one of the research scientists.

Professor John Anderson and Dr. Michelle Maclean with the HINS-light system (Photo courtesy University of Strathclyde)

Microbiologists Professor John Anderson and Dr. Michelle Maclean, and optical physicist Professor Gerry Woolsey, are co-discoverers and developers of the HINS-light system.

“The technology kills pathogens but is harmless to patients and staff, which means for the first time, hospitals can continuously disinfect wards and isolation rooms,” said Professor Anderson.

“The system works by using a narrow spectrum of visible-light wavelengths to excite molecules contained within bacteria, he explains. “This in turn produces highly reactive chemical species that are lethal to bacteria such as meticillin-resistant Staphylococcus aureus, or MRSA, and Clostridium difficile, known as C.diff.”

A two-year clinical trial of the HINS-light system was supported by funding of 440,000 pounds from the Scottish Enterprise Proof of Concept Programme.

Dr. Maclean said, “The clinical trials have shown that the technology can help prevent the environmental transmission of pathogens and thereby increase patient safety.”

The technology uses HINS-light which has a violet hue, but the research team have used a combination of LED technologies to produce a warm white lighting system that can be used alongside normal hospital lighting.

Professor Scott MacGregor, dean of the Faculty of Engineering, said, “New approaches to disinfection and sterilisation are urgently needed within the clinical environment, as traditional methods have significant limitations.

“Decontamination methods involving gas sterilants or UV-light can be hazardous to staff and patients, while cleaning, disinfection and hand washing, although essential routine procedures, have limited effectiveness and problems with compliance,” MacGregor said.

“HINS-light is a safe treatment that can be easily automated to provide continuous disinfection of wards and other areas of the clinical environment,” said MacGregor.

HINS-light shines on a petri dish (Photo courtesy University of Strathclyde)

Methicillin-resistant Staphylococcus aureus infection is caused by a strain of staph bacteria that has become resistant to the antibiotics commonly used to treat ordinary staph infections. MRSA can burrow deep into the body, causing life-threatening infections in bones, joints, surgical wounds, the bloodstream, heart valves and lungs.

Most MRSA infections occur in people who have been in hospitals or other health care settings, such as nursing homes and dialysis centers. This infection is associated with invasive procedures or devices, such as surgeries, intravenous tubing or artificial joints. Carriers of MRSA can spread it, even if they are not sick themselves.

Another type of MRSA infection occurs in the wider community among healthy people. Outbreaks of MRSA have occurred in military training camps, child care centers and jails.

Clostridium difficile are bacteria that can cause swelling and irritation of the large intestine, or colon. This inflammation, known as colitis, can cause diarrhea, fever, and abdominal cramps and can be passed from person to person. The infection is most common in people who are taking antibiotics while in the hospital and is especially common in older people in hospitals and nursing homes.

The HINS-light technology was developed in Strathclyde’s Robertson Trust Laboratory for Electronic Sterilisation Technologies, which is dedicated to controlling infection in health care environments.

The research has been supported by the University of Strathclyde, The Robertson Trust and the Scottish Enterprise Proof of Concept Programme, which supports the pre-commercialization of leading-edge technologies emerging from Scotland. Commercialization could begin after another six months of tests.

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