UV-C light cuts transmission rates for superbug infections

The newest weapon in the fight against superbugs may be a very expensive light bulb, according to a recent study published in The Lancet.

In a large randomized trial, Duke University researchers found that the use of short-wave UV-C machines can cut transmission rates of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Clostridium difficile, and multidrug-resistant Acinetobacter. This finding was specific to patients who stay overnight in a room where someone with a known positive culture or infection of a drug-resistant organism had previously been treated.

Some facilities have already added UV-C to standard chemical disinfection protocols, but research has been preliminary to date.

The Duke study involved nine hospitals in the southeastern US. Rooms in which a patient with infection or colonization with one of the four target organisms were terminally disinfected with one of four strategies:

• Bleach
• Bleach and UV-C
• Quaternary ammonium (for C difficile, bleach was used)
• Quaternary ammonium and UV-C (for C difficile, bleach and UV-C were used).

For the study, researchers used a portable machine called the Tru-D SmartUVC. The machine emits UV-C light into an empty room for about 30 minutes. The light bounces and reflects into hard-to-reach areas, such as open drawers or between cabinets and fixtures.

The most effective overall strategy was quaternary ammonium followed by UV-C—this combination was particularly effective against transmission of MRSA. The use of chlorine bleach instead of quaternary ammonium cut transmission of VRE by more than half, and the addition of UV-C to bleach cut VRE transmission by 64%.

None of the cleaning methods significantly reduced the incidence of C difficile. Acinetobacter was present in only one case, so it was not included in the analysis.

“Some of these [pathogens] can live on the environment so long that even after a patient with the organism has left and the room has been cleaned, the next patient in the room could potentially be exposed,” said Deverick J. Anderson, MD, an infectious disease specialist at Duke Health and lead investigator of the trial. “For hospitals, these infections also cause a burden of costs that often aren’t reimbursable.”

It is important to note that the improvement in disinfection comes at a cost. Several companies now manufacturer the machines, but they are generally priced at $90,000 or more. The cost savings associated with prevention of infections may not offset the economic impact of the initial purchase and the additional room vacancy times needed while the UV-C is operating.

“There is such a push in the hospital environment to turn rooms over,” Dr. Anderson said. “Any amount of added time is viewed as a potential issue. In a large hospital, you may have 100 rooms that are vacated and turned over in 1 day.”

Despite the cost and delay in room turnover, hospitals in the trial achieved 90% compliance, in that they were able to disinfect 90% of the targeted rooms while following the exact trial protocol.

The CDC Prevention Epicenters Program, the National Institute of Allergy and Infectious Diseases, and the National Center for Advancing Translational Sciences sponsored the study. Tru-D SmartUVC, Ecolab, Clorox, Angelica Corporation, and Shared Linen Services donated materials.