Hydrogen peroxide vapour enhances hospital disinfection of superbugs
Johns Hopkins to begin decontaminating isolation rooms with Bioquell robotic devices
Infection control experts at the Johns Hopkins Hospital in Maryland in the US have found that a combination of robot-like devices that disperse a bleaching agent into the air and then detoxify the disinfecting chemical are highly effective at killing and preventing the spread of multiple-drug-resistant bacteria, or hospital superbugs.
A study report on the use of hydrogen peroxide vaporisers – first deployed in Singapore hospitals during the 2002 outbreak of severe acute respiratory syndrome, or SARS, and later stocked by several US government agencies in case of an anthrax attack – has been published in the journal Clinical Infectious Diseases.
In the study, the Johns Hopkins team placed the devices in single hospital rooms after routine cleaning to disperse a thin film of the bleaching hydrogen peroxide across all exposed hospital equipment surfaces, as well as on room floors and walls.
Our study results are evidence that technological solutions, when combined with standard cleaning, can effectively and systematically decontaminate patients’ rooms
Results showed that the enhanced cleaning reduced by 64% the number of patients who later became contaminated with any of the most common drug-resistant organisms. In addition, protection from infection was conferred on patients regardless of whether the previous room occupant was infected with drug-resistant bacteria or not.
The researchers also found that enhanced cleaning with the vapour reduced by 80% a patient’s chances of becoming colonised by hard-to-treat bacterium such as vancomycin-resistant enterococci (VRE).
The scientists also routinely tested patients and their surroundings for the more common methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile and Acinetobacter baumannii.
Some 6,350 patient admissions to Johns Hopkins were closely tracked as part of the 30-month study. Almost half the 180 rooms received enhanced cleaning with hydrogen peroxide vapour in between patients, while the rest did not. Overall, multiple-drug-resistant organisms were found on room surfaces in 21% of rooms tested, but mostly in rooms that did not undergo enhanced cleaning.
Trish Perl, infectious disease specialist and study senior investigator, says patients bringing in or picking up drug-resistant organisms while undergoing treatment in hospitals is a persistent and growing problem, and previous research has shown that patients who stay in a hospital room previously occupied by an infected patient are at greater risk of becoming infected.
What is so exciting about this new method of infection control is that the devices are easy to use
“Our study results are evidence that technological solutions, when combined with standard cleaning, can effectively and systematically decontaminate patients’ rooms and augment other behavioural practices, such as strict hospital staff compliance with hand-washing and bathing patients in disinfecting chlorhexidine when they are first admitted to the hospital,” says Perl, senior hospital epidemiologist for the Johns Hopkins Health System and a professor at the Johns Hopkins University School of Medicine.
“Our goal is to improve all hospital infection control practices, including cleaning and disinfection, as well as behavioural and environmental practices, to the point where preventing the spread of these multiple-drug-resistant organisms also minimises the chances of patients becoming infected and improves their chances of recovery,” she says.
Bioquell of Horsham, PA, provided the paired robot-like devices, each about the size of a washing machine and weighing nearly 60lb, as well as supplies used in the study.
After the room has been cleaned, the vents are covered and the two devices are placed inside. The sliding door is closed, and the room is sealed. Then, the larger of the two devices disperses hydrogen peroxide into the room, leaving a very tiny, almost invisible layer (only 2–6 microns in thickness) on all exposed surfaces, including keyboards and monitors, as well as tables and chairs.
Because hydrogen peroxide can be toxic to humans if ingested or corrosive if left on the skin for too long, the second, smaller device is activated to break down the bleach into its component water and oxygen parts. The combined operation takes the devices about 90min to complete.
“What is so exciting about this new method of infection control is that the devices are easy to use and hospital staff embrace it very quickly,” says surgeon and study co-investigator Pamela Lipsett.
As a result of the study and the researchers' recommendation, Johns Hopkins has bought two of the Bioquell decontaminating units, which cost more than $40,000 a pair. The devices, already in use at some 20 other hospitals across the US, will be used at Johns Hopkins to decontaminate rooms typically housing high-risk patients under strict isolation precautions because of severe infection with a multiple-drug-resistant organism.
The researchers next plan to study the devices' effectiveness at decontaminating the outside packaging of unused but potentially exposed hospital supplies, which are typically discarded even though their seals remain intact.
