RokStories Ultraviolet Light Could Be Enlisted In Battle Against Hospital Infections
Black lights, once a staple of college dorm rooms, now appear to be an effective weapon in the battle against certain drug-resistant bacteria common to hospital acquired infection (HAI).

Although of a different wavelength than the old counter culture black lights, ultraviolet light is increasingly seen as a front line defense for cleaning hospital rooms and appears to be more effective in the elimination of disease resistant bacteria such as Clostridium difficile (C. diff), Acinetobacter, and vancomycin-resistant Enterococcus (VRE) than earlier, more common methods including manual cleaning and vaporized hydrogen peroxide.

Nearly invisible to the human eye, UV-C is short wave ultraviolet radiation. Recent research confirms that UV-C kills these bacteria commonly found on door handles, bedside tables, toilets and other surfaces in hospital rooms.

For decades UF-C light had a track record in purifying food, air and waste and sterilizing medical equipment.

In nature, the UV-C wavelength component of sunlight destroys pathogens such as viruses, mold, bacteria and mildew. It does this by breaking through the outer membrane of the microbes reaching the DNA of the microbe, thereby causing modifications. The DNA then transmits incorrect codes, causing the death of the microbes.

The same process occurs with the UV-C lamps researchers are studying.

According to an October 2012 study presented at IDWeek, a major infectious disease conference, researchers at Duke University Medical Center and the University of North Carolina Hospital System used UV-C to nearly eliminate the bugs in more than 50 patient rooms at the two medical centers.

This study, according to lead researcher Deverick J. Anderson, MD, an assistant professor of medicine at Duke and co-director of the Duke Infection Control Outreach Center, demonstrates that the medical application of UF-C may help reduce the estimated 1.7 million HAIs that occur annually in the United States. The costs associated with treating these infections have been estimated between $4.5 and $11 billion.

And to make matters worse, these bacteria are becoming increasingly resistant to antibiotics, making a cleaner hospital environment more important than ever.

“We are learning more and more about how much the hospital environment contributes to the spread of these organisms,” Dr. Anderson says.

In their study, researchers examined whether UV-C could eliminate three of the most problematic germs, thereby improving the cleanliness of patient rooms. The Duke study covered both intensive care as well as general medical rooms and identified patients with C. diff, a trigger for a serious intestinal condition; Acinetobacter, a cause of pneumonia and serious wound and urinary tract infections; and VRE, an infector of urinary tract, bloodstream, wounds and catheter sites.

After these patients were discharged but before standard terminal room disinfection by cleaning personnel, researchers took culture samples from specific locations in the rooms including bedside rail, bedside table, chair arm, over bed table, and sink counter. The toilet, shower floor, and floor adjacent to the toilet were also cultured in targeted rooms from which a patient with C. diff infection was discharged.

Then a special, eight-bulb UV-C machine was positioned near the center of the room and turned on for up to 45 minutes. Then 15 more cultures were taken from the same locations and compared to the pre-treatment bacteria samples.

The results were startling. Fifty-two colony-forming units (CFUs) of Acinetobacter were seen before irradiation, but only 1 CFU afterward – down 98.1 percent. The other two bacteria had nearly the same proportional decrease.

Dr. Anderson notes the recent Duke study shows that the use of UV-C “succeeds in both the experimental and real world.” He adds that he doesn’t believe that UV-C should be the only form of cleaning a room, but that is another tool in the fight against HAIs.

Unlike traditional antimicrobial cleaning agents, UV light disinfects every surface of the room that is bathed in the light. Traditional hand and machine cleaning methods often miss up to 50 percent of the surfaces, thereby allowing the spread of bacteria. Bathrooms, researchers found, were particularly hard to thoroughly clean.

A recent study conducted at the University of North Carolina Health notes, for example, of 20,646 standardized environmental surfaces (14 types of objects) only 9,910 (48 %) were cleaned at terminal room cleaning according to institutional room cleaning policies. This data, coupled with the fact that patients admitted to rooms previously occupied by people infected or colonized with methicillin -resistant Staphylococcus aureus (MRSA), VRE or C. diff are at a significant risk of acquiring these organisms, shows the importance of room cleaning.

Chuck Dunn, president of Lumalier Corporation, manufacturer of UV-C lighting equipment, notes there are three primary factors affecting the performance of ultraviolet light in rooms – the size of the room, the geometry of the room and the color and reflectivity of the wall, ceilings, floors and objects.

Lumalier, he notes, donated the UV-C machine for the aforementioned Duke study. This lighting unit, says Dunn, has an array of built-in sensors that measure the light reflecting to the machine. This tells the unit how much light is reaching the room and calculates how long it should stay on to provide a lethal dosage of light. He notes that one of the worst-case scenarios is trying to disinfect a brown door in a white room. The light wants to turn off sooner than necessary due to the reflectivity of the white walls.

“We want to improve reflectivity in a room to speed up disinfection time and to ensure every surface is clean, Dunn explains.

To that end, he says, his company has also developed a highly reflective paint ingrained with nanoscale inorganic oxides whose crystal structures are transparent to UV-C and act as prisms to make the UF-C light doses more lethal. Dunn explains that while standard white latex paint is 3%-7% reflective of UV-C light, the special coating is 65% UV reflective.

The UNC study compared a hospital room painted with standard white paint-coated walls versus walls painted with this paint formulated to be reflective of UV-C wavelengths. The cycle time to achieve microbial killing was determined in this room before and after the room was coated with the special paint.

According to the UNC research, the cycle time of the lighting array was slightly over five minutes with the coating and over 25 minutes without coating with respect to MRSA. For C. diff spores, the cycle time was about nine and a half minutes with the coating and nearly 44 minutes without the coating.

A major disadvantage to both UV-C light systems as well as the more traditional hydrogen peroxide vaporization, according to the UNC study, is that they can only be used for terminal disinfection, not daily use, because the rooms must be emptied of people.

Another drawback to hydrogen peroxide systems, the study finds, is the time required for decontamination. The UV-C system offers faster decontamination (15-20 minutes, compared with 2-5 hours for hydrogen peroxide systems), before the development of this UV-C reflective coating, but with the use of this coating innovation cycle times were 5-10 minutes, which would significantly reduce (by approximately 80%) the room’s downtime before another patient could be admitted.

Although UV-C light shows great promise in hospital room disinfection, Dr. Anderson’s study points out that end results of disinfection are greater when the light is used after the room has been cleaned using traditional cleaning protocols.

“Because cultures were obtained before and after application of UV-C light in rooms that had not undergone standard cleaning and disinfection, it is possible that the efficacy of UV-C was adversely affected by the presence of dirt and debris on surfaces and equipment,” the study says.

It continues to say, “our results suggest that UV-C disinfection may be more effective when used with traditional cleaning protocols. Thus cleaning must remain an important part of terminal room disinfection, but in its absence or on locations missed by cleaning staff, more than 90% of pathogenic bacteria will still be killed when an automated UV-C device is used.”

“We have a solid foundation to show that this approach (UV-C) succeeds in both experimental and real-world conditions. Now it’s time to see if we can demonstrate that it indeed decreases the rate of infections among patients,” Dr. Anderson concludes.

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