Hydrogen Peroxide Vapor Can Control Nosocomial MRSA Outbreak

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18 September 2007 (Reuters Health [Deborah Mitchell])-Hydrogen peroxide vapor, in combination with decolonization of staff and patient carriers, successfully controlled an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) on a surgical ward that had previously been MRSA free, a British research team reported at the 47th annual Interscience Conference of Antimicrobial Agents and Chemotherapy.

In January 2007, MRSA was detected during the routine culture of minor surgical wound infections in 2 patients who were located in different sections of a ward at the Royal County Hospital in Winchester. Further screening of all 28 patients on the ward identified MRSA colonization in 11 (39.2%).

MRSA was also detected in 6 out of 52 healthcare workers on the ward, and environmental sampling indicated “substantial” MRSA contamination throughout the ward on various surfaces.

The hospital infection control team, led by Dr. Matthew Dryden, decided to use hydrogen peroxide vapor, which has previously been used for MRSA in other hospitals, to decontaminate the area.

The patients and staff were decolonized; other microbial control measures included reinforcement of the importance of proper hand hygiene, cleaning, and decontamination. Because of the shortage of available beds, the ward could not be cleared of patients, so the hydrogen peroxide vapor was administered in sections over a 2-day period. The patients, staff and the ward environment were monitored for the next 4 weeks.

At follow-up, all of the staff members and patients remained decolonized for MRSA. Over this period, all of the 69 patients who were discharged were MRSA negative. Of the 81 patients who were admitted, 3 tested positive for MRSA. After the hydrogen peroxide vapor decontamination, no new MRSA acquisitions occurred among the patients or staff.

Only 1 environmental site - a bed frame - remained MRSA positive after hydrogen peroxide vapor treatment.

Otter, a microbiologist at BIOQUELL Ltd. in Andover, UK, and his group initially believed this to be a single‐strain MRSA outbreak, but distinct subtypes were detected in 5 out of 9 patients who were colonized, and 7 out of 8 variants in the staff and environment matched a patient isolate.

The presence of the 5 distinct MRSA subtypes suggests repeated MRSA exposure due to the admission of different MRSA-positive patients.

Overall, the investigators conclude that hydrogen peroxide, plus patient and staff decontamination, ended the MRSA outbreak and that the effect was maintained up to at least 4 weeks.

BIOQUELL developed the hydrogen peroxide vapor for microbial decontamination about 10 years ago, and it has been used in the health sector for about 5 years, Otter continued.

“We can't say which of these interventions was most important, but chances are it was a combination,” Otter said. “It is a multifaceted problem.”

Hydrogen peroxide vapor can also be used successfully as a prophylaxis, Otter said. In June of 2005, St. Raphael's Hospital in New Haven, Connecticut, USA, tried it after a Clostridium difficile outbreak. Daily decontamination was performed for 10 months in hospital rooms of discharged patients who had had C. difficile. “We were able to show a 53% reduction in the rate of nosocomial C. difficile-associated disease compared with the historical period, and that the difference was statistically significant,” Otter said.

The message from this study, he concluded, is “when you do have an outbreak of a nosocomial pathogen, hydrogen peroxide vapor is now a viable option as part of the outbreak response.”

Editor's comment. "According to my consultant Dr. Keith Kaye at Duke Medical Center, who has researched hydrogen peroxide vapor sterilization technology, the technology is probably good for spores (e.g., C. difficile and anthrax), viruses (e.g., severe acute respiratory syndrome virus), and bacteria (e.g., MRSA). The biggest limitation of the technology is time. It takes 4-8 h until a room can be safely used."

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