Hydrogen Peroxide Vapour Decontamination Research Articles

1919. Implementation of Hydrogen Peroxide Vapor (HPV) Decontamination of N95 Respirators for Reuse During COVID-19 Pandemic

Abstract Background To ensure an adequate supply of N95 respirators in response to the global shortages caused by the COVID-19 pandemic, we evaluated and implemented hydrogen peroxide vapor (HPV) to reprocess disposable N95 respirators. Previous work performed by our team showed that HPV was effective in eradicating viable viruses from experimentally contaminated N95 respirators and that they retained their breathability and filtering efficiency for 3 cycles of HPV disinfection. Methods A multidisciplinary team worked by performing experiments and PDSA cycles to develop the ultimate process. Key processes and stakeholders were identified and engaged in operations decisions. Results The respirator reprocessing program was successfully implemented. One of the critical components for its success was the implementation of a Personal Protective Equipment (PPE) liaison program which was developed to create a process and local, unit-level champion for the collection of used N95s and to educate the staff on the program and provide guidance per the hospitals’ PPE policy. A courier system was implemented for the collection, transport and delivery of bulk containers of respirators between facilities. Facility Services designed and constructed a centralized respirator reprocessing center to include a receiving location, a negative pressure decontamination area to sort and stage the respirators on racks, two HPV reprocessing rooms and a clean room to receive the reprocessed N95s and to repackage and label for distribution. Standard operating procedures, staff training and competencies, and logs for documentation were created. Within 18 weeks (March 13, 2020 through July 2020), nearly 32,000 N95 respirators were reprocessed and packaged for redistribution utilizing the 2 HPV disinfection rooms and 5 full time employees. As built, there was capacity to reprocess 5,000 respirators per day and evaluated by the U. S. Food and Drug Administration (FDA) led to the issue of an Emergency Use Authorization. Conclusion This scalable program enabled YNHHS to ensure an adequate supply of respirators for the safety of staff during the COVID-19 pandemic and global shortages of PPE. A multidisciplinary team and leadership commitment to provide resources for space and personnel were critical for program success. Disclosures All Authors: No reported disclosures.

Evaluation of hydrogen peroxide efficacy against AZD1222 chimpanzee adenovirus strain in the recombinant COVID-19 vaccine for application in cleaning validation in a pharmaceutical manufacturing industry.

This study aimed to evaluate the performance of hydrogen peroxide vapour (HPV) to inactivate the chimpanzee adenovirus AZD1222 vaccine strain used in the production of recombinant COVID-19 vaccine for application in cleaning validation in pharmaceutical industries production areas. Two matrixes were tested: formulated recombinant COVID-19 vaccine (FCV) and active pharmaceutical ingredient (API). The samples were dried on stainless steel and exposed to HPV in an isolator. One biological indicator with population >106 Geobacillus stearothermophilus spores was used to validate the HPV decontamination cycle as standard. HPV exposure resulted in complete virus inactivation in FVC (≥5·03 log10 ) and API (≥6·40 log10 ), showing HPV efficacy for reducing chimpanzee adenovirus AZD1222 vaccine strain. However, the optimum concentration and contact time will vary depending on the type of application. Future decontamination studies scaling up the process to the recombinant COVID-19 vaccine manufacturing areas are necessary to evaluate if the HPV will have the same or better virucidal effectivity in each specific production area. In conclusion, HPV showed efficacy for reducing AZD1222 chimpanzee adenovirus strain and can be a good choice for pharmaceutical industries facilities disinfection during recombinant COVID-19 vaccine production.

Large-scale decontamination of disposable FFP2 and FFP3 respirators by hydrogen peroxide vapour, Finland, April to June 2020.

BackgroundThe shortage of FFP2 and FFP3 respirators posed a serious threat to the operation of the healthcare system at the onset of the COVID-19 pandemic.AimOur aim was to develop and validate a large-scale facility that uses hydrogen peroxide vapour for the decontamination of used respirators.MethodsA multidisciplinary and multisectoral ad hoc group of experts representing various organisations was assembled to implement the collection and transport of used FFP2 and FFP3 respirators from hospitals covering 86% of the Finnish population. A large-scale decontamination facility using hydrogen peroxide vapour was designed and constructed. Microbiological tests were used to confirm efficacy of hydrogen peroxide vapour decontamination together with a test to assess the effect of decontamination on the filtering efficacy and fit of respirators. Bacterial and fungal growth in stored respirators was determined by standard methods.ResultsLarge-scale hydrogen peroxide vapour decontamination of a range of FFP2 and FFP3 respirator models effectively reduced the recovery of biological indicators: Geobacillus stearothermophilus and Bacillus atrophaeus spores, as well as model virus bacteriophage MS2. The filtering efficacy and facial fit after hydrogen peroxide vapour decontamination were not affected by the process. Microbial growth in the hydrogen peroxide vapour-treated respirators indicated appropriate microbial cleanliness.ConclusionsLarge-scale hydrogen peroxide vapour decontamination was validated. After effective decontamination, no significant changes in the key properties of the respirators were detected. European Union regulations should incorporate a facilitated pathway to allow reuse of appropriately decontaminated respirators in a severe pandemic when unused respirators are not available.

Hydrogen Peroxide Vapor Decontamination of Hazard Group 3 Bacteria and Viruses in a Biosafety Level 3 Laboratory.

This study aimed to validate the efficacy of hydrogen peroxide vapor (HPV) decontamination technology set up in a biosafety level 3 (BSL-3) laboratory on surrogates and hazard group 3 (HG3) agents. The HPV decontamination system (Bioquell) was assessed with both qualitative and quantitative methods on (1) spore surrogates (Geobacillus stearothermophilus, Bacillus atrophaeus, and Bacillus thuringiensis) in the BSL-3 laboratory and in the material airlock and on (2) HG3 agents (Bacillus anthracis; SARS-CoV-2, Venezuelan equine encephalitis virus [VEE], and Vaccinia virus) in the BSL-3 laboratory. Other HG3 bacteria likely to be handled in the BSL-3 laboratory (Yersinia pestis, Burkholderia mallei, Brucella melitensis, and Francisella tularensis) were excluded from the HPV decontamination assays as preliminary viability tests demonstrated the total inactivation of these agents after 48 h drying on different materials. The efficacy of HPV decontamination was validated with a reduction in viability of 5-7 log10 for the spores (surrogates and B. anthracis), and for the enveloped RNA viruses. Vaccinia showed a higher resistance to the decontamination process, being dependent on the biological indicator location in the BSL-3 laboratory.

Decontamination of respirators amid shortages due to SARS-CoV-2.

The pandemic created by SARS-CoV-2 has caused a shortage in the supplies of N95 filtering facepiece respirators (FFRs), disposable respirators with at least 95% efficiency to remove non-oily airborne particles, due to increasing cases all over the world. The current article reviewed various possible decontamination methods for FFR reuse including ultraviolet germicidal irradiation (UVGI), hydrogen peroxide vapor (HPV), microwave-generated steam (MGS), hydrogen peroxide gas plasma (HPGP), and 70% or higher ethanol solution. HPV decontamination was effective against bacterial spores (6 log10 reduction of Geobacillus stearothermophilus spores) on FFRs and viruses (> 4 log10 reduction of various types of viruses) on inanimate surfaces, and no degradation of respirator materials and fit has been reported. 70% or higher ethanol decontamination showed high efficacy in inactivation of coronaviruses on inanimate surfaces (> 3.9 log10 reduction) but it was lower on FFRs which filtration efficiency was also decreased. UVGI method had good biocidal efficacy on FFRs (> 3 log10 reduction of H1N1 virus) combined with inexpensive, readily available equipment; however, it was more time-consuming to ensure sufficient reduction in SARS-CoV-2. MGS treatment also provided good viral decontamination on FFRs (> 4 log10 reduction of H1N1 virus) along with less time-intensive process and readily available equipment while inconsistent disinfection on the treated surfaces and deterioration of nose cushion of FFRs were observed. HPGP was a good virucidal system (> 6 log10 reduction of Vesicular stomatitis virus) but filtration efficiency after decontamination was inconsistent. Overall, HPV appeared to be one of the most promising methods based on the high biocidal efficacy on FFRs, preservation of respirator performance after multiple cycles, and no residual chemical toxicity. Nonetheless, equipment cost and time of the HPV process and a suitable operating room need to be considered.

Real-time monitoring of hydrogen peroxide vapour decontamination of bacterial spores by means of UV fluorimetry

Real-time monitoring of hydrogen peroxide vapour decontamination of bacterial spores by means of UV fluorimetry

Policy and Pandemic: The Changing Practice of Nephrology During the Coronavirus Disease-2019 Outbreak.

The coronavirus (coronavirus disease-2019) pandemic has changed care delivery for patients with end-stage kidney disease. We explore the US healthcare system as it pertains to dialysis care, including existing policies, modifications implemented in response to the coronavirus disease-2019 crisis, and possible next steps for policy makers and nephrologists. This includes policies related to resource management, use of telemedicine, prioritization of dialysis access procedures, expansion of home dialysis modalities, administrative duties, and quality assessment. The government has already established policies that have instated some flexibilities to help providers focus their response to the crisis. However, future policy during and after the coronavirus disease-2019 pandemic can bolster our ability to optimize care for patients with end-stage kidney disease. Key themes in this perspective are the importance of policy flexibility, clear strategies for emergency preparedness, and robust health systems that maximize accessibility and patient autonomy.

Decontamination and Reuse of N95 Respirators with Hydrogen Peroxide Vapor to Address Worldwide Personal Protective Equipment Shortages During the SARS-CoV-2 (COVID-19) Pandemic.

Decontamination and Reuse of N95 Respirators with Hydrogen Peroxide Vapor to Address Worldwide Personal Protective Equipment Shortages During the SARS-CoV-2 (COVID-19) Pandemic.

COVID-19 global pandemic planning: Decontamination and reuse processes for N95 respirators.

Coronavirus disease 2019 (COVID-19) is an illness caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease was first identified as a cluster of respiratory illness in Wuhan City, Hubei Province, China, in December 2019, and has rapidly spread across the globe to greater than 200 countries. Healthcare providers are at an increased risk for contracting the disease due to occupational exposure and require appropriate personal protective equipment (PPE), including N95 respirators. The rapid worldwide spread of high numbers of COVID-19 cases has facilitated the need for a substantial supply of PPE that is largely unavailable in many settings, thereby creating critical shortages. Creative solutions for the decontamination and safe reuse of PPE to protect our frontline healthcare personnel are essential. Here, we describe the development of a process that began in late February 2020 for selecting and implementing the use of hydrogen peroxide vapor (HPV) as viable method to reprocess N95 respirators. Since pre-existing HPV decontamination chambers were not available, we optimized the sterilization process in an operating room after experiencing initial challenges in other environments. Details are provided about the prioritization and implementation of processes for collection and storage, pre-processing, HPV decontamination, and post-processing of filtering facepiece respirators. Important lessons learned from this experience include, developing an adequate reserve of PPE for effective reprocessing and distribution, and identifying a suitable location with optimal environmental controls (i.e. operating room). Collectively, information presented here provides a framework for other institutions considering decontamination procedures for N95 respirators.Impact statementThere is a critical shortage of personal protective equipment (PPE) around the globe. This article describes the safe collection, storage, and decontamination of N95 respirators using hydrogen peroxide vapor (HPV). This article is unique because it describes the HPV process in an operating room, and is therefore, a deployable method for many healthcare settings. Results presented here offer creative solutions to the current PPE shortage.

Modelling vaporised hydrogen peroxide efficacy against mono-species biofilms

This pilot study investigates a novel approach towards efficacy testing of antimicrobial cleaning agents; focusing primarily on hydrogen peroxide vapour (HPV). Contaminated surfaces are recognised modes of pathogen transmission within healthcare environments and increase the risk of pathogen acquisition in newly admitted patients. Studies have shown these pathogens can survive on surfaces for extended periods of time in spite of cleaning. This resilience is characteristic of biofilm formation and recent publications have identified their presence in hospitals. In this study, biofilm models comprised of multidrug-resistant organisms (MDROs) were generated using a drip flow reactor and exposed to HPV decontamination. The MDROs included Acinetobacter baumannii, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Upon exposure, samples were periodically removed and enumerated to generate kill curves for each species. Consequently revealing any inherent resistances; such as catalase-producing organisms which expressed reduced susceptibility. Epifluorescence microscopy revealed an abundance of viable and non-viable microcolonies before and after decontamination, respectively. Greater than 6-Log10 reduction was achieved within a 100 minutes exposure time. This pilot study puts forward a potential methodology for testing antimicrobial agents against biofilms and supports the efficacy of HPV.

Evaluating the efficacy of hydrogen peroxide vapour against foot-and-mouth disease virus within a BSL4 biosafety facility.

Foot-and-mouth disease virus (FMDV) is an important pathogen in terms of biosafety due to its infectious nature and wide range of host animals, such as cattle, sheep, goats and pigs. Outbreaks of FMDV can have a severe impact on livestock production, causing morbidity, mortality, reduced yields and trade embargoes. Laboratories studying FMDV must possess BSL4 robust bio-decontamination methods to prevent inadvertent release. Formaldehyde has been the primary agent for environmental decontamination, but its designation as a human carcinogen has led to a search for alternatives. This study shows 35% hydrogen peroxide vapour has the potential to be a rapid, effective, residue-free alternative.

Counting the cost of an outbreak of carbapenemase-producing Enterobacteriaceae: an economic evaluation from a hospital perspective

ObjectiveTo perform an economic evaluation on the cost associated with an outbreak of carbapenemase-producing Enterobacteriaceae (CPE). MethodsWe performed an observational economic evaluation of an outbreak of CPE (NDM-producing Klebsiella pneumoniae) affecting 40 patients in a group of five hospitals across three sites in West London. Costs were split into actual expenditure (including anti-infective costs, enhanced CPE screening, contact precautions, temporary ward-based monitors of hand and environmental practice, and environmental decontamination), and ‘opportunity cost’ (staff time, bed closures and elective surgical missed revenue). Costs are estimated from the hospital perspective over the 10-month duration of the outbreak. ResultsThe outbreak cost €1.1m over 10 months (range €0.9–1.4m), comprising €312 000 actual expenditure, and €822 000 (range €631 000–€1.1m) in opportunity cost. An additional €153 000 was spent on Estates renovations prompted by the outbreak. Actual expenditure comprised: €54 000 on anti-infectives for 18 patients treated, €94 000 on laboratory costs for screening, €73 000 on contact precautions for 1831 contact precautions patient-days, €42 000 for hydrogen peroxide vapour decontamination of 24 single rooms, €43 000 on 2592 hours of ward-based monitors, and €6000 of expenditure related to ward and bay closures. Opportunity costs comprised: €244 000 related to 1206 lost bed-days (range 366–2562 bed-days, €77 000–€512 000), €349 000 in missed revenue from 72 elective surgical procedures, and €228 000 in staff time (range €205 000–€251 000). Reduced capacity to perform elective surgical procedures related to bed closures (€349 000) represented the greatest cost. ConclusionsThe cost estimates that we present suggest that CPE outbreaks are highly costly.

Hydrogen Peroxide Vapor Decontamination in a Patient Room Using Feline Calicivirus and Murine Norovirus as Surrogate Markers for Human Norovirus.

To determine whether hydrogen peroxide vapor (HPV) could be used to decontaminate caliciviruses from surfaces in a patient room. Feline calicivirus (FCV) and murine norovirus (MNV) were used as surrogate viability markers to mimic the noncultivable human norovirus. Cell culture supernatants of FCV and MNV were dried in triplicate 35-mm wells of 6-well plastic plates. These plates were placed in various positions in a nonoccupied patient room that was subsequently exposed to HPV. Control plates were positioned in a similar room but were never exposed to HPV. Virucidal activity was measured in cell culture by reduction in 50% tissue culture infective dose titer for FCV and by both 50% tissue culture infective dose titer and plaque reduction for MNV. Neither viable FCV nor viable MNV could be detected in the test room after HPV treatment. At least 3.65 log reduction for FCV and at least 3.67 log reduction for MNV were found by 50% tissue culture infective dose. With plaque assay, measurable reduction for MNV was at least 2.85 log units. The successful inactivation of both surrogate viruses indicates that HPV could be a useful tool for surface decontamination of a patient room contaminated by norovirus. Hence nosocomial spread to subsequent patients can be avoided.

Efficacy of two hydrogen peroxide vapour aerial decontamination systems for enhanced disinfection of meticillin-resistant Staphylococcus aureus, Klebsiella pneumoniae and Clostridium difficile in single isolation rooms

Hydrogen peroxide vapour (HPV) disinfection systems are being used to reduce patients' exposure to hospital pathogens in the environment. HPV whole-room aerial disinfection systems may vary in terms of operating concentration and mode of delivery. To assess the efficacy of two HPV systems (HPS1 and HPS2) for whole-room aerial disinfection of single isolation rooms (SIRs). Ten SIRs were selected for manual terminal disinfection after patient discharge. Test coupons seeded with biological indicator (BI) organisms [∼10(6) colony-forming units (cfu) of meticillin-resistant Staphylococcus aureus (MRSA) or Klebsiella pneumoniae, or ∼10(5)cfu Clostridium difficile 027 spores] prepared in a soil challenge were placed at five locations per room. For each cycle, 22 high-frequency-touch surfaces in SIRs were sampled with contact plates (∼25cm(2)) before and after HPV decontamination, and BIs were assayed for the persistence of pathogens. Approximately 95% of 214 sites were contaminated with bacteria after manual terminal disinfection, with high numbers present on the SIR floor (238.0-352.5cfu), bed control panel (24.0-33.5cfu), and nurse call button (21.5-7.0cfu). Enhanced disinfection using HPV reduced surface contamination to low levels: HPS1 [0.25cfu, interquartile range (IQR) 0-1.13] and HPS2 (0.5cfu, IQR 0-2.0). Both systems demonstrated similar turnaround times (∼2-2.5h), and no differences were observed in the efficacy of the two systems against BIs (C.difficile ∼5.1log10 reduction; MRSA/K.pneumoniae ∼6.3log10 reduction). Despite different operating concentrations of hydrogen peroxide, MRSA persisted on 27% of coupons after HPV decontamination. Enhanced disinfection with HPV reduces surface contamination left by manual terminal cleaning, minimizing the risks of cross-contamination. The starting concentration and mode of delivery of hydrogen peroxide may not improve the efficacy of decontamination in practice, and therefore the choice of HPV system may be based upon other considerations such as cost, convenience and logistics.

Terminal decontamination of the Royal Free London's high-level isolation unit after a case of Ebola virus disease using hydrogen peroxide vapor

We report the decontamination of the high-level isolation unit at the Royal Free London after the discharge of a patient with Ebola virus disease, who was repatriated from West Africa. Hydrogen peroxide vapor (HPV) was used to decontaminate the patient care isolators and the rooms housing them. HPV decontamination was completed without incident and allowed the unit to be returned to service more quickly than the previous protocol of using formaldehyde.

Identification and control of a gentamicin resistant, meticillin susceptible Staphylococcus aureus outbreak on a neonatal unit.

We describe the identification and control of an outbreak of gentamicin resistant, meticillin susceptible Staphylococcus aureus (GR-MSSA) on a 36-bed neonatal unit (NNU) in London. Control measures included admission and weekly screening for GR-MSSA, cohorting affected babies, environmental and staff screening, hydrogen peroxide vapour (HPV) for terminal disinfection of cohort rooms, and reinforcement of hand hygiene. Seventeen babies were affected by the outbreak strain over ten months; seven were infected and ten were asymptomatic carriers. The outbreak strain was gentamicin resistant and all isolates were indistinguishable by pulsed-field gel electrophoresis. The outbreak strains spread rapidly and were associated with a high rate of bacteraemia (35% of 17 affected patients had bacteraemia vs. 10% of 284 patients with MSSA prior to the outbreak, p=0.007). None of 113 staff members tested were colonised with GR-MSSA. GR-MSSA was recovered from 11.5% of 87 environmental surfaces in cohort rooms, 7.1% of 28 communal surfaces and 4.1% of 74 surfaces after conventional terminal disinfection. None of 64 surfaces sampled after HPV decontamination yielded GR-MSSA. Recovery of GR-MSSA from two high level sites suggested that the organism could have been transmitted via air. Occasional breakdown in hand hygiene compliance and contaminated environmental surfaces probably contributed to transmission.

Keeping New Delhi Metallo-β-lactamase-1 at the Door

New Delhi metallo-β-lactamase-1 is a recently described gene that codes for carbapenem resistance. Inherently transferable between Gram-negative bacteria on a plasmid that also confers extended antibiotic resistance, it represents a potentially serious problem for susceptible patients, such as burn victims, and is spreading globally at a rapid rate. The authors present a case of a septic burn patient returning from India, whose microbiological cultures grew bacteria expressing New Delhi metallo-β-lactamase-1. His TBSA was 14%. His length of stay as an inpatient was 95 days. This is the first case report of this resistance strain from a U.K. burns unit. Isolation, barrier nursing and the use of hydrogen peroxide vapor decontamination proved effective in limiting transmission and spread. The authors are of the opinion that their experience has implications for the management of similar cases in the future.

Implementation of hospital-wide enhanced terminal cleaning of targeted patient rooms and its impact on endemic Clostridium difficile infection rates

Implementation of a hospital-wide program of terminal cleaning of patient rooms revolving around hydrogen peroxide vapor (HPV) technology and evaluation of its impact on endemic nosocomial Clostridium difficile-associated diarrhea (CDAD) have not been previously reported. This was a retrospective quasiexperimental study involving a 900-bed community hospital. During the preintervention period (January 2007-November 2008), rooms vacated by patients with CDAD or on contact precautions for other targeted pathogens underwent 1 or more rounds of cleaning with bleach. During the intervention period (January-December 2009), targeted newly evacuated rooms underwent "enhanced cleaning" consisting of use of bleach followed by HPV decontamination utilizing a priority scale based on the pathogen and room location. Rooms vacated by patients with CDAD but for which HPV decontamination was not possible the same day underwent 4 rounds of cleaning with bleach instead. During the intervention period, 1,123 HPV decontamination rounds were performed involving 96.7% of hospital rooms. Of 334 rooms vacated by patients with CDAD (May-December 2009), 180 (54%) underwent HPV decontamination. The rate of nosocomial CDAD rate dropped significantly from 0.88 cases/1,000 patient-days to 0.55 cases/1,000 patient-days (rate ratio, 0.63; 95% confidence interval: 0.50-0.79, P < .0001). A hospital-wide program of enhanced terminal cleaning of targeted patient rooms revolving around HPV technology was practical and was associated with a significant reduction in CDAD rates.

Editorial Commentary: Climbing the Evidentiary Hierarchy for Environmental Infection Control

Increasing concern over multidrug-resistant organisms (MDROs), especially vancomycin-resistant enterococci (VRE), Clostridium difficile, and multidrugresistant gram-negative bacteria (MDRGNB), has led to increasing attention being paid to the role of high-touch environmental surfaces in transmission. Our current understanding of the roles of environmental surfaces in MDRO transmission include the following: (1) a primary role with transmission from source patient to environmental surface to subsequent patient, and (2) a secondary role from source patient to environmental surface to hands of healthcare personnel to subsequent patient. Either a prior room occupant or a contemporaneous patient sharing reusable medical equipment is the source patient in most primary transmission events. Standard environmental cleaning and disinfection entails manual cleaning and application of a disinfectant, often utilizing a detergent disinfectant. In addition to new disinfectants with greater potency and shorter contact times, new technological advances include “nontouch disinfection” (NTD) methods, the most developed of which are hydrogen peroxide vapor (HPV), and automated germicidal ultraviolet irradiation. Both methods appear highly efficacious in inactivating the microbial bioburden present on surfaces, and both remove much of the variance inherent in human cleaning activity via a high degree of automation and feedback loops for verification that contact or irradiation times are adequate [1–3]. Despite these advances, demonstrating the clinical impact of both old and new environmental cleaning and disinfection technologies remains challenging. We propose an evidentiary hierarchy for assessing any environmental disinfection strategy (Figure 1), beginning with a foundation (ie, level I) of laboratory efficacy studies similar to those required for registration by the Environmental Protection Agency [4]. Numerous patient and practice factors confound the relationship between environmental bioburden reductions and MDRO transmission interruption, from the number of patients on antibiotics with wounds, devices, and diarrhea (rendering them either more contagious or susceptible to colonization), to rates of compliance with hand hygiene and isolation, to interventions aimed at source control such as chlorhexidine bathing. Because only a small proportion of all MDRO acquisitions lead to eventual infection, linking infection reductions to environmental bioburden reductions (ie, level V of Figure 1) is even more challenging. However, because infections correlate more closely than colonization with mortality, excess length of stay, and cost, such linkage will eventually become necessary to calculate the cost-effectiveness of new technologies. Such a hierarchy can assist the development of a new disinfection technology, guiding industry in demonstrating achievement at a lower level in the hierarchy before investment is made at a higher level. It also highlights the need for tools to link achievements at lower levels (eg, achievable log10 reductions in the laboratory or as part of an in-use study) to the likelihood of success at a higher level. Standardized methods for environmental and hand sampling, microbiologic cultures, and assessment of adherence to standard environmental cleaning, hand hygiene, and isolation precautions will all be important to make the climbing of this hierarchy more efficient. The report by Passaretti et al in this issue of Clinical Infectious Diseases, in which investigators found that HPV decontamination of MDRO patient rooms was associated with a 45% reduction in environmental contamination and 80% reduction in acquisition of VRE among patients with a prior MDRO-colonized Received 11 September 2012; accepted 18 September 2012; electronically published 5 October 2012. Correspondence: L. Clifford McDonald, MD, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, 1600 Clifton Rd, MS07, Atlanta, GA 30333 (cmcdonald1@cdc.gov). Clinical Infectious Diseases 2013;56(1):36–9 Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved 2012. DOI: 10.1093/cid/cis845

Impact of the suspending medium on susceptibility of meticillin-resistant Staphylococcus aureus to hydrogen peroxide vapour decontamination

Several factors influence the in vitro susceptibility of microbes to disinfectants. We evaluated the impact of various suspending media on the susceptibility of meticillin-resistant Staphylococcus aureus (MRSA) to hydrogen peroxide vapour (HPV) decontamination. From a >6 log(10) inoculum, relative susceptibility was 10% bovine serum albumin (BSA) < TSB < 3% BSA < saline < 0.3% BSA = water. MRSA was not recovered after >60 min exposure to HPV for all suspensions. These findings indicate that the suspending medium has an effect on the in vitro susceptibility of MRSA to HPV, which may have implications in the case of suboptimal cleaning.