Continuous decontamination between episodes of manual cleaning is the Holy
Grail.”— Dr. David
Weber frequently on palms / fingertips( 76 percent) and nares( 71 percent). C. auris contamination was detected on 32.2 percent( 66 / 205) of room surfaces before disinfection and 20.5 percent( 39 / 190) of room surfaces by 4 hours after disinfection. A higher number of C. auris-colonized body sites was associated with higher odds of environmental contamination at every time point following disinfection, adjusting for facility of residence. In the rooms of 38( 93 percent) C. auris carriers co-colonized with a bacterial MDRO, 2 percent to 24 percent of surfaces were additionally contaminated with the same MDRO by 4 hours after disinfection.
Weber emphasized the Sansom study confirmed that C. auris can contaminate the healthcare environment rapidly after disinfection, highlighting the challenges associated with environmental disinfection. The authors said that future research should investigate long-acting disinfectants, antimicrobial surfaces, and more effective patient skin antisepsis to reduce the environmental reservoir of C. auris and bacterial MDROs in healthcare settings, and Weber noted,“ This is why there is such an emphasis now on developing antimicrobial-impregnated surfaces or continuous room disinfection.”
Weber continued,“ Continuous decontamination between episodes of manual cleaning is the Holy Grail. Candidate technologies include continuously active surface disinfectants, antimicrobial gases( electronic air cleaning technologies), air cleaning technologies producing reactive oxygen species, hydroxyl radicals and hydrogen peroxide gas, as well as ultraviolet light. The wish list is efficacy, addressing surface and air, being automated, being safe and being reasonably priced.”
Weber acknowledged that there is currently no widely accepted standard“ of how much you have to inactivate on a surface, but I would say if you can get an activation of three logs, that’ s probably adequate to reduce HAIs via the environment,” he said.
Weber said he appreciated the approach taken in the study by Warren, et al.( 2022)“ because they split the room in half and one side got the long-acting disinfectant and half didn’ t, so then it controls for things like hand hygiene by healthcare providers, and the level of surface cleaning by environmental services( EVS) technicians.
In that randomized clinical trial( RCT), the authors compared the efficacy of an enhanced daily disinfection strategy vs standard disinfection in acute-care hospital rooms. Rooms were occupied by patients with contact precautions. Room surfaces( bed rails, overbed table, and in-room sink) were divided into two sides( right vs. left), allowing each room to serve as its own control. Each side was randomized 1:1 to the intervention group or control group. The intervention was a quaternary ammonium, salt-based, 24-hour continuously active germicidal wipe. It was applied in addition to routine disinfection for the intervention group. The control group received no intervention beyond routine disinfection. A total of 50 study rooms occupied by 50 unique patients with contact precautions were enrolled. Of these patients, 41( 82 percent) were actively receiving antibiotics, 39( 78 percent) were bedridden, and 28( 56 percent) had active infections with study-defined clinically important pathogens. On study day 1, the median( IQR) total CFUs for the intervention group was lower than that for the control group( 3561 [ 1292-7602 ] CFUs vs. 5219 [ 1540-12 364 ] CFUs). On study day 1, the intervention side was less frequently contaminated with patient-associated clinically important pathogens compared with the control side of the room.
“ They showed that on day 1, the colony-forming units and the intervention group are lower than the controlled group, statistically speaking,” Weber emphasized.“ The long-acting disinfectant achieved a better kill over time in the control and the intervention group. They have conducted these real-world studies and looking at overall disinfection; most, but not all studies demonstrated that in the real world evaluation of these continuously acting disinfectants, they did achieve a statistical reduction compared to whatever control was being used.”
Weber expressed concerns about the use of antimicrobial copper.
“ With copper, durability has been a concern,” he said.“ You can see this by looking at pennies with resistant microbes living on them; it doesn’ t mean we wouldn’ t develop resistance to this if you used it widely. Regarding copper-coated surfaces and HAIs – if you do these studies, you really have to monitor hand hygiene, monitor environmental cleaning, otherwise you don’ t really know if something goes down or goes up, and some of the studies that did show a decrease in HAIs were not statistically significant. Copper is not ready to be widely used, despite some microbial and microbiocidal activity. It’ s not practical to coat every surface in the patient room, so it’ s unclear what surfaces you would actually coat, and the other problem is that different copper compounds have not been well studied; the HAI studies have been mixed and no cost-benefit analyses done, and again, durability is a challenge.”
Weber continued,“ For air cleaning we have photocatalytic oxidation, dilute / hydrogen peroxide, bipolar ionization, but we don’ t have good data whether they really reduce HAIs, which to me is the gold standard. We should demand not just showing that you have decreased bioburden on the surfaces. None of these are easy or inexpensive to implement or maintain. There’ s blue light at 405 nanometers that we’ ve studied and you can see a statistical decrease but again, it was not really meaningful for us to reduce vegetative bacteria. I think we need better and larger studies. Many studies on far UV-C light( 222 nm) showed a one to two-log reduction, and an occasional study showed greater than three logs; none of these studies have assessed the importance of dry surface biofilms.”
In conclusion, Weber summarized that continuously active quaternary ammonium disinfectants are easily removed, lab tests exaggerate efficacy, method of application impacts real-world efficacy; and clinical studies yield mixed results. Copper is impossible to coat all room surfaces, durability is unclear, and bacterial resistance may emerge. There is limited and mixed efficacy data. For antimicrobial gasses( electronic air-cleaning technologies), there is limited efficacy data – some quasi-experimental studies show reductions in surface contamination with dry hydrogen peroxide; lab testing shows no reduction in bacterial pathogens. There is a potential concern about the production of harmful ozone. Dilute hydrogen peroxide below permissible exposure limit of 1 part per mission( ppm) or 1,000 parts per billion( ppb) as an eight-hour time-weighted average. There is limited and mixed efficacy data. For far UV-C, it appears to be promising technology for continuous air and surface decontamination in occupied spaces.
26 • www. healthcarehygienemagazine. com • nov-dec 2025