Vapour-phase hydrogen peroxide inactivates Yersinia pestis dried on polymers, steel, and glass surfaces

A Systematic Review on the Efficacy of Vaporized Hydrogen Peroxide as a Non-Contact Decontamination System for Pathogens Associated with the Dental Environment

Aerosol generation and a wide range of pathogens originating from the oral cavity of the patient contaminate various surfaces of the dental clinic. The aim was to determine the efficacy of vaporized hydrogen peroxide fogging on pathogens related to the dental environment and its possible application in dentistry. PICOS statement (Population, Intervention, Comparison/Control, Outcome and Study design statement) was used in the review. Six electronic databases were searched for articles published from 2010 to 2020. Articles written in English reporting vaporized hydrogen peroxide on pathogens deemed to be relevant to the dental environment were assessed. The quality of the studies was assessed using the risk-of-bias assessment tool designed for the investigation of vaporized hydrogen peroxide application in dentistry. A total of 17 studies were included in the qualitative synthesis. The most commonly reported single bacterial pathogen was Methicillin-resistant Staphylococcus aureus in five studies, and the viruses Feline calicivirus, Human norovirus, and Murine norovirus were featured in three studies. The results of the studies reporting the log kill were sufficient for all authors to conclude that vaporized hydrogen peroxide generation was effective for the assessed pathogens. The studies that assessed aerosolized hydrogen peroxide found a greater log kill with the use of vaporized hydrogen peroxide generators. The overarching conclusion was that hydrogen peroxide delivered as vaporized hydrogen peroxide was an effective method to achieve large levels of log kill on the assessed pathogens. The hydrogen peroxide vapor generators can play a role in dental bio-decontamination. The parameters must be standardized and the efficacy assessed to perform bio-decontamination for the whole clinic. For vaporized hydrogen peroxide generators to be included in the dental bio-decontamination regimen, certain criteria should be met. These include the standardization and efficacy assessment of the vaporized hydrogen peroxide generators in dental clinics.

Hazard Group 3 agent decontamination using hydrogen peroxide vapour in a class III microbiological safety cabinet

AIMS

This study investigated the efficacy of hydrogen peroxide vapour (HPV) at inactivating hazard group 3 bacteria that have been presented dried from their growth medium to present a realistic challenge.

METHODS AND RESULTS

Hydrogen peroxide vapour technology (Bioquell) was used to decontaminate a class III microbiological safety cabinet containing biological indicators (BIs) made by drying standard working suspensions of the following agents: Bacillus anthracis (Ames) spores, Brucella abortus (strain S99), Burkholderia pseudomallei (NCTC 12939), Escherichia coli O157 ST11 (NCTC 12079), Mycobacterium tuberculosis (strain H37Rv) and Yersinia pestis (strain CO92) on stainless steel coupons. Extended cycles were used to expose the agents for 90 min. The HPV cycle completely inactivated B. anthracis spores, B. abortus, B. pseudomallei, E. coli O157 and Y. pestis when BIs were processed using quantitative and qualitative methods. Whilst M. tuberculosis was not completely inactivated, it was reduced by 4 log₁₀ from a starting concentration of 10⁶ colony-forming units.

CONCLUSIONS

This study demonstrates that HPV is able to inactivate a range of HG3 agents at high concentrations with associated organic matter, but M. tuberculosis showed increased resistance to the process.

SIGNIFICANCE AND IMPACT OF THE STUDY

This publication demonstrates that HPV can inactivate HG3 agents that have an organic load associated with them. It also shows that M. tuberculosis has higher resistance to HPV than other agents. This shows that an appropriate BI to represent the agent of interest should be chosen to demonstrate a decontamination is successful.

A simple decontamination approach using hydrogen peroxide vapour for Bacillus anthracis spore inactivation

AIMS

To evaluate the use of relatively low levels of hydrogen peroxide vapour (HPV) for the inactivation of Bacillus anthracis spores within an indoor environment.

METHODS AND RESULTS

Laboratory-scale decontamination tests were conducted using bacterial spores of both B. anthracis Ames and Bacillus atrophaeus inoculated onto several types of materials. Pilot-scale tests were also conducted using a larger chamber furnished as an indoor office. Commercial off-the-shelf (COTS) humidifiers filled with aqueous solutions of 3 or 8% hydrogen peroxide (H₂ O₂ ) were used to generate the HPV inside the mock office. The spores were exposed to HPV for periods ranging from 8 h up to 1 week.

CONCLUSIONS

Four- to seven-day exposures to low levels of HPV (average air concentrations of approx. 5-10 parts per million) were effective in inactivating B. anthracis spores on multiple materials. The HPV can be generated with COTS humidifiers and household H₂ O₂ solutions. With the exception of one test/material, B. atrophaeus spores were equally or more resistant to HPV inactivation compared to those from B. anthracis Ames.

SIGNIFICANCE AND IMPACT OF THE STUDY

This simple and effective decontamination method is another option that could be widely applied in the event of a B. anthracis spore release.

Decontamination of a BSL3 laboratory by hydrogen peroxide fumigation using three different surrogates for Bacillus anthracis spores

AIMS

Two independent trials investigated the decontamination of a BSL3 laboratory using vaporous hydrogen peroxide and compared the effect on spores of Bacillus cereus, Bacillus subtilis and Bacillus thuringiensis as surrogates for Bacillus anthracis spores, while spores of Geobacillus stearothermophilus served as control.

METHODS AND RESULTS

Carriers containing 1·0 × 10(6) spores were placed at various locations within the laboratory before fumigation with hydrogen peroxide following a previously validated protocol. Afterwards, carriers were monitored by plating out samples on agar and observing enrichment in nutrient medium for up to 14 days. Three months later, the experiment was repeated and results were compared. On 98 of 102 carriers, no viable spores could be detected after decontamination, while the remaining four carriers exhibited growth of CFU only after enrichment for several days. Reduction factors between 4·0 and 6·0 log levels could be reached.

CONCLUSIONS

A validated decontamination of a laboratory with hydrogen peroxide represents an effective alternative to fumigation with formaldehyde. Spores of B. cereus seem to be more resistant than those of G. stearothermophilus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study provide important results in the field of hydrogen peroxide decontamination when analysing the effect on spores other than those of G. stearothermophilus.

Systematic evaluation of the efficacy of chlorine dioxide in decontamination of building interior surfaces contaminated with anthrax spores

Efficacy of chlorine dioxide (CD) gas generated by two distinct generation systems, Sabre (wet system with gas generated in water) and ClorDiSys (dry system with gas generated in air), was evaluated for inactivation of Bacillus anthracis spores on six building interior surfaces. The six building materials included carpet, acoustic ceiling tile, unpainted cinder block, painted I-beam steel, painted wallboard, and unpainted pinewood. There was no statistically significant difference in the data due to the CD generation technology at a 95% confidence level. Note that a common method of CD gas measurement was used for both wet and dry CD generation types. Doses generated by combinations of different concentrations of CD gas (500, 1,000, 1,500, or 3,000 parts per million of volume [ppmv]) and exposure times (ranging between 0.5 and 12 h) were used to evaluate the relative role of fumigant exposure period and total dose in the decontamination of building surfaces. The results showed that the time required to achieve at least a 6-log reduction in viable spores is clearly a function of the material type on which the spores are inoculated. The wood and cinder block coupons required a longer exposure time to achieve a 6-log reduction. The only material showing a clear statistical difference in rate of decay of viable spores as a function of concentration was cinder block. For all other materials, the profile of spore kill (i.e., change in number of viable spores with exposure time) was not dependent upon fumigant concentration (500 to 3,000 ppmv). The CD dose required for complete spore kill on biological indicators (typically, 1E6 spores of Bacillus atrophaeus on stainless steel) was significantly less than that required for decontamination of most of the building materials tested.