Effectiveness Of Decontamination Methods Research Articles

The Effect of Decontamination Methods on the Functionality of N95 Respirators in Particle Removal and SARS-CoV-2 Eradication

The Effect of Decontamination Methods on the Functionality of N95 Respirators in Particle Removal and SARS-CoV-2 Eradication

Fiber-Based Masks and Respirators: Using Decontamination Methods and Antimicrobial Treatment to Improve Its Reusability during Pandemic

Shortage of personal protective equipment (PPE) is often projected in response to public health emergencies such as infection outbreaks and pandemics. Respiratory protective devices (RPDs), namely medical face masks and respirators, are considered the last defense for the front-line healthcare workers. Cleaning, decontamination and reuse of the disposable RPDs have been accepted by local health authorities during the pandemic period. To contribute to the mitigation of RPD shortage and ensure the safe adoption of decontamination protocols, this review discusses the regulated testing standards and the most commonly studied decontamination methods in the literature. The reuse of RPDs must fulfill three criteria: remove the microbial thread, maintain original function and structural integrity (including fitting tests) and leave no harmful residuals. Decontamination methods such as ultraviolet germicidal irradiation, moist heat and vaporized hydrogen peroxide appeared to be the most promising methods in balancing the above-mentioned criteria. However, the effectiveness of decontamination methods varies depending on the RPDs’ models, materials and design. Therefore, the adoption of protocols needs to be evidence-based with full validation in the local institutes. Additionally, new technology such as antimicrobial treated PPE that can reduce the risks of fomite during donning and doffing process with an extended lifespan should be encouraged. Overall, good training and guidance for appropriate reuse of RPDs are fundamental to ensure their efficiency in protecting front-line healthcare workers.

Studies of the Effect of Decontamination Methods on the Surface Condition of the Stoppers in Contact with Drugs

The influence of means and modes of sanitary-hygienic treatments on the surface condition of medical rubber stoppers based on butyl and halobutyl rubbers used for sealing injection and infusion drugs was investigated using the method of determining the contact wetting angle on a DCAT 21 tensiometer. It has been established that the methods used for sanitary-hygienic processing have a destructive effect on the state of the surface, accompanied by a decrease in the edge angle of wetting (an increase in the hydrophilicity of the surface of the stoppers), which significantly increases the possibility of interaction with the dissolved pharmaceutical substances of drugs.

Neutral electrolyzed water (NEW), chlorine dioxide, organic acid based product, and ultraviolet-C for inactivation of microbes in fresh-cut vegetable washing waters

The effect of decontamination methods on fresh-cut vegetable washing waters was evaluated. NEW, ClO2, organic acid-based product FPW, and UV-C were tested with and without an interfering carrot juice of 1% (IS), on Yersinia enterocolitica and Yersinia pseudotuberculosis, Escherichia coli, and yeast Candida lambica. The use of ClO2 (50 ppm active chlorine) resulted in >4 log reduction of Y. enterocolitica, Y. pseudotuberculosis, E. coli and >3 log reduction of C. lambica. The antibacterial effect of NEW was less effective in the presence of IS when compared with ClO2. The inactivation of C. lambica by FPW reached a maximum of 2.8 log cfu/mL (concentration 0.125%), but the antimicrobial effect was delayed by the IS. The effect of FPW on E. coli was significantly reduced by 1% IS. The inactivation of E. coli and C. lambica with UV-C IS decreased the inactivation and lengthened its time. Filtration improved the effect of UV-C inactivation. Practical applications When chemical decontamination methods were used in fresh-cut vegetable processing, the presence of organic matter in process water increased the reaction times and the need for higher concentrations of the chemical decontamination and the time of physical decontamination. Yersinia required longer inactivation times than E. coli. When UV-C is used for decontamination of process waters, waters should be filtered to enhance the disinfection efficacy.

Decontamination of autogenous bone grafts: systematic literature review and evidence-based proposal of a protocol.

There is a lack of consensus guidelines for the decontamination of autogenous bone grafts after exposure to a nonsterile environment during graft contouring, intraoral bone harvesting, or when inadvertently dropped off the sterile field. Transplantation of contaminated bone may cause infectious complications or even augmentation failure. When selecting the antimicrobial agent of choice to treat harvested bone for transplantation purposes, focus should be placed on the safety of the agent towards bone and osteoprogenitor cells, maximum elimination of targeted pathogens that directly affect bone tissue, and a short exposure time. In systematically reviewing study results on the degree of bone graft contamination and the effects of decontamination methods, a protocol for decontamination of autogenous bone grafts is proposed. Among various decontamination agents investigated, 1% chlorhexidine proved highly effective (mean reduction of bacterial colony-forming units compared to saline solution: 99.97%). Minimum contact time required is 15 seconds and cell proliferation can be observed up to 30 seconds of exposure. The proposed decontamination protocol (1% chlorhexidine for 15 seconds) seems to represent a reasonable compromise in reference to sterility and cell viability. Comparative effectiveness research, however, is needed before clinical recommendations may be posed.

Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators

Concerns have been raised regarding the availability of National Institute for Occupational Safety and Health (NIOSH)-certified N95 filtering facepiece respirators (FFRs) during an influenza pandemic. One possible strategy to mitigate a respirator shortage is to reuse FFRs following a biological decontamination process to render infectious material on the FFR inactive. However, little data exist on the effects of decontamination methods on respirator integrity and performance. This study evaluated five decontamination methods [ultraviolet germicidal irradiation (UVGI), ethylene oxide, vaporized hydrogen peroxide (VHP), microwave oven irradiation, and bleach] using nine models of NIOSH-certified respirators (three models each of N95 FFRs, surgical N95 respirators, and P100 FFRs) to determine which methods should be considered for future research studies. Following treatment by each decontamination method, the FFRs were evaluated for changes in physical appearance, odor, and laboratory performance (filter aerosol penetration and filter airflow resistance). Additional experiments (dry heat laboratory oven exposures, off-gassing, and FFR hydrophobicity) were subsequently conducted to better understand material properties and possible health risks to the respirator user following decontamination. However, this study did not assess the efficiency of the decontamination methods to inactivate viable microorganisms. Microwave oven irradiation melted samples from two FFR models. The remainder of the FFR samples that had been decontaminated had expected levels of filter aerosol penetration and filter airflow resistance. The scent of bleach remained noticeable following overnight drying and low levels of chlorine gas were found to off-gas from bleach-decontaminated FFRs when rehydrated with deionized water. UVGI, ethylene oxide (EtO), and VHP were found to be the most promising decontamination methods; however, concerns remain about the throughput capabilities for EtO and VHP. Further research is needed before any specific decontamination methods can be recommended.

Effects of decontamination methods and culture conditions on viability of Mycobacterium ulcerans in the BACTEC system.

We used the BACTEC system to evaluate the effects of several decontamination methods and the addition of antibiotics on the viability of Mycobacterium ulcerans. The effects of polyoxyethylene stearate or egg yolk as supplements were also evaluated to determine their impact on the growth of M. ulcerans. Strains of different geographic origins were subjected to Petroff, reversed Petroff, oxalic acid, and mild HCI treatments. After treatment, the viability of each strain was assessed in the BACTEC system. All of the decontamination methods tested adversely affected bacterial viability. Treatment with mild HCl gave the best results, allowing better growth rates with some strains and causing a delay in growth with others, depending on the geographic origin of the strain. A mixture of polymyxin B, amphotericin B, nalidixic acid, trimethoprim, and azlocillin did not significantly inhibit growth. Supplementing BACTEC medium with egg yolk markedly improved the recovery of M. ulcerans following the use of each of the decontamination methods. Our findings demonstrate a detrimental impact on the viability of M. ulcerans by all of the decontamination methods currently in common use. This explains, at least in part, the difficulty often experienced in cultivating this organism from clinical specimens. Egg yolk should be added to enhance the rate of successful primary cultivation of M. ulcerans in the BACTEC system.