Use of semi-permeable bag materials to facilitate on-site treatment of biological agent-contaminated waste.

Clean up following the wide-area release of a persistent biological agent has the potential to generate significant waste. Waste containing residual levels of biological contaminants may require off-site shipment under the U.S. Department of Transportation's (US DOT) solid waste regulations for Category A infectious agents, which has packaging and size limitations that do not accommodate large quantities. Treating the waste on-site to inactivate the bio-contaminants could alleviate the need for Category A shipping and open the possibility for categorizing the waste as conventional solid waste with similar shipping requirements as municipal garbage. To collect and package waste for on-site treatment, a semi-permeable nonwoven-based fabric was developed. The fabric was designed to contain residual bio-contaminants while providing sufficient permeability for penetration by a gaseous decontamination agent. The nonwoven fabric was tested in two bench-scale experiments. First, decontamination efficacy and gas permeability were evaluated by placing test coupons inoculated with spores of a Bacillus anthracis surrogate inside the nonwoven material. After chlorine dioxide fumigation, the coupons were analyzed for spore viability and results showed a ≥6 Log reduction on all test materials except glass. Second, filters cut from the nonwoven material were tested in parallel with commercially available cellulose acetate filters having a known pore size (0.45 µm) and results demonstrate that the two materials have similar permeability characteristics. Overall, results suggest that the nonwoven material could be used to package waste at the point of generation and then moved to a nearby staging area where it could be fumigated to inactivate bio-contaminants.

Evaluation of disinfection methods for personal protective equipment (PPE) items for reuse during a pandemic.

The COVID-19 pandemic resulted in many supply chain issues, including crippling of essential personal protective equipment (PPE) needed for high-risk occupations such as those in healthcare. As a result of these supply chain issues, unprecedented crisis capacity strategies were implemented to divert PPE items such as filtering facepiece respirators (FFRs, namely N95s) to those who needed them most for protection. Large-scale methods for decontamination were used throughout the world to preserve these items and provided for their extended use. The general public also adopted the use of non-specialized protective equipment such as face coverings. So, the need for cleaning, decontamination, or disinfection of these items in addition to normal clothing items became a necessary reality. Some items could be laundered, but other items were not appropriate for washing/drying. To fill research gaps in small-scale, non-commercial cleaning and disinfection, this bench-scale research was conducted using small coupons (swatches) of multiple PPE/barrier protection materials inoculated with virus (non-pathogenic bacteriophages Phi6 and MS2) and tested against a range of decontamination methods including bleach-, alcohol- and quaternary ammonium compound (QAC)-based liquid sprays, as well as low concentration hydrogen peroxide vapor (LCHPV) and bench-scale laundering. In general, non-porous items were easier to disinfect than porous items, and the enveloped virus Phi6 was overall easier to inactivate than MS2. Multiple disinfection methods were shown to be effective in reducing viral loads from PPE coupons, though only laundering and LCHPV were effective for all materials tested that were inoculated with Phi6. Applications of this and follow-on full-scale research are to provide simple effective cleaning/disinfection methods for use during the current and future pandemics.

Impact of filter material and holding time on spore sampling efficiency in water.

Bacillus anthracis and other environmentally persistent pathogens pose a significant threat to human and environmental health. If contamination is spread over a wide area (e.g. resulting from a bioterrorism or biowarfare incident), readily deployable and scalable sample collection methods will be necessary for rapidly developing and implementing effective remediation strategies. A recent surge in environmental (eDNA) sampling technologies could prove useful for quantifying the extent and levels of contamination from biological agents in environmental and drinking water. In this study, three commonly used membrane filtration materials (cellulose acetate, cellulose nitrate, and nylon) were evaluated for spore filtration efficiency, yielding recoveries from 17%-68% to 25%-117% for high and low titer samples, respectively, where cellulose nitrate filters generated the highest recoveries. A holding time test revealed no statistically significant differences between spore recoveries when analyzed at the specified timepoints, suggesting that eDNA filter sampling techniques can yield and maintain a relatively high recovery of spores for an extended period of time between filtration and analysis without a detrimental impact on spore recoveries. The results shown here indicate that emerging eDNA technologies could be leveraged for sampling following a wide-area contamination incident and for other microbiological water sampling applications.

Determining Viral Disinfection Efficacy of Hot Water Laundering.

This protocol provides an example of a laboratory process for conducting laundering studies that generate data on viral disinfection. While the protocol was developed for research during the coronavirus disease 2019 (COVID-19) pandemic, it is intended to be a framework, adaptable to other virus disinfection studies; it demonstrates the steps for preparing the test virus, inoculating the test material, assessing visual and integrity changes to the washed items due to the laundering process, and quantifying the reduction in viral load. Additionally, the protocol outlines the necessary quality control samples for ensuring the experiments are not biased by contamination and measurements/observations that should be recorded to track the material integrity of the personal protective equipment (PPE) items after multiple laundering cycles. The representative results presented with the protocol use the Phi6 bacteriophage inoculated onto cotton scrub, denim, and cotton face-covering materials and indicate that the hot water laundering and drying process achieved over a 3-log (99.9%) reduction in viral load for all samples (a 3-log reduction is the disinfectant performance metric in U.S. Environmental Protection Agency's Product Performance Test Guideline 810.2200). The reduction in viral load was uniform across different locations on the PPE items. The results of this viral disinfection efficacy testing protocol should help the scientific community explore the effectiveness of home laundering for other types of test viruses and laundering procedures.

Virucidal efficacy of antimicrobial surface coatings against the enveloped bacteriophage Φ6.

AIMS: Antimicrobial coatings, for use in combination with routine cleaning and disinfection, were evaluated for their effectiveness in reducing virus concentration on stainless steel surfaces. METHODS: Twenty antimicrobial coating products, predominantly composed of organosilane quaternary ammonium compounds, were applied to stainless steel coupons, dried overnight and evaluated for efficacy against Φ6, an enveloped bacteriophage. Additionally, two peel and stick polymer-based films, a copper-based film and three copper alloys were evaluated. Efficacy was determined by comparison of recoveries from uncoated (positive control) and coated (test) surfaces. RESULTS: The results indicated that some of the coating products initially demonstrated >3-log reduction of Φ6; no direct correlation of efficacy was observed with an active ingredient or its concentration. The peel and stick films and copper alloys each demonstrated efficacy in initial testing. However, none of the spray-based products retained efficacy after subjecting the coating to abrasion with either a hypochlorite or quaternary ammonium-based solution applied in accordance with EPA Interim Guidance for Evaluating the Efficacy of Antimicrobial Surface Coatings. Of the products tested for this durability, only one peel and stick polymeric film retained efficacy; the copper alloys were not tested for their durability in this study. CONCLUSIONS: These results suggest that while some organosilane quaternary ammonium compound-based products demonstrate antiviral efficacy, more research and development is needed to understand effective formulations with sufficient durability to perform as supplements to routine cleaning and disinfection.