UV-light disinfection might cut hospital MRSA, VRE rates

An expensive type of ultraviolet (UV) light treatment called UVC was associated with a 30% drop in the incidence of infections with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) but did not affect Clostridium difficile rates when used for cleaning hospital rooms between patients, according to a study yesterday in The Lancet.

The study, conducted by Duke Health researchers and funded by the US Centers for Disease Control and Prevention, was conducted from 2012 to 2014 at nine hospitals in the Southeast, including three Duke University Health System hospitals, a Veterans Affairs hospital, and small community facilities. It included 21,393 patients.

The hospitals used a portable UVC machine to disinfect rooms where patients with the target bacteria had been staying. For about 30 minutes, the device emits UVC light into an empty room and kills bacteria by disrupting their DNA.

The trial compared standard disinfection with quaternary ammonium to three other cleaning methods: using quaternary ammonium followed by UV light, applying chlorine bleach instead of quaternary ammonium and no UV light, and cleaning with bleach and UV light.

Overall, the most effective strategy was using quaternary ammonium followed by UV light, which was particularly effective against MRSA. Using chlorine bleach instead of quaternary ammonium cut VRE by more than half, and adding UV light to the bleach regimen was even more successful, cutting VRE transmission 64%. Adding UV light did not change the C difficile rate for any method.

"Some of these germs can live on the environment so long that even after a patient with the organism has left the room and it 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, in a Duke University news release. "Infections from one of these bugs are tough and expensive to treat and can be truly debilitating for a patient. For hospitals, these infections also cause a burden of costs that often aren't reimbursable."

In a Lancet commentary, experts from Methodist Dallas Medical Center, who weren't involved in the study, wrote, "These results are welcome at a time of crucial action in combatting resistant microbes. . . . Further investigation of the role of UV light in preventing C difficile infection, including multiple cycles and bathroom disinfection, is warranted to decipher the lack of clinical effect for this key pathogen."

Potential detriments include the price tag of the UVC unit, which can be as high as $90,000, and the relatively long disinfection time. Larger hospitals, which might turn over 100 patient beds in a day, might not be able to spare an extra half hour for room cleaning, Anderson said.
Jan 16 Lancet study
Jan 16 Lancet commentary
Jan 16 Duke University news release

Study finds high colonization rates of drug-resistant pathogens in refugees

A new study suggests that refugees seeking asylum in Europe may be bringing with them higher carriage rates of antibiotic-resistant bacteria.

In the observational study, published in PLoS One, 261 refugees at four refugee centers in Switzerland were screened to determine colonization rates for MRSA and extended-spectrum beta-lactamase (ESBL) and carbapenemase-producing Enterobacteriaceae. Pharyngeal, nasal, and inguinal swabs were used for MRSA screening, and rectal swabs and urine were used for ESBL and carbapenemase screening.

The refugees were from five different regions—Middle East, East Africa, Central/West Africa, Northern Africa, and Far East—with the majority coming from Afghanistan, Syria, and Eritrea. Three quarters of the screening participants were male.

The screening results showed that 15.7% of the refugees were colonized with MRSA, a rate roughly 10 times higher than found in the Swiss population. But the rate of colonization ranged widely between the four refugee centers, with one particular center showing a colonization rate of 25.4%. The study authors determined, through the use of whole-genome sequencing, that this was likely due to a large outbreak in that camp and a series of smaller transmission events. The authors suggest that the living conditions in the refugee centers could facilitate MRSA transmission.

The ESBL colonization rate among the refugees was 23.7%, about 2 to 5 times higher compared to the Swiss population, with significantly higher colonization in persons originating from the Middle East. All the ESBL strains were Escherichia coli. Because no EBL isolates were available for whole-genome sequencing, it could not be determined if person-to-person transmission within a refugee center was taking place, as was the case with MRSA. No carbapenemase-producing isolates were identified.

"In summary, our data suggests, that for all refugees admitted to medical care facilities in Europe, screening and potentially contact isolation should be performed," the authors write.
Jan 13 PLoS One study