A new physical and biological strategy to reduce the content of zearalenone in infected wheat kernels: the effect of cold needle perforation, microorganisms, and purified enzyme

With the aim of reintroducing wheat grains naturally contaminated with mycotoxins into the food value chain, a decontamination strategy was developed in this study. For this purpose, in a first step, the whole wheat kernels were pre-treated using cold needle perforation. The pore size was evaluated by scanning electron microscopy and the accessibility of enzymes and microorganisms determined using fluorescent markers in the size range of enzymes (5 nm) and microorganisms (10 μm), and fluorescent microscopy. The perforated wheat grains, as well as non-perforated grains as controls, were then incubated with selected microorganisms (Bacillus megaterium Myk145 and B. licheniformis MA572) or with the enzyme ZHD518. The two bacilli strains were not able to significantly reduce the amount of zearalenone (ZEA), neither in the perforated nor in the non-perforated wheat kernels in comparison with the controls. In contrast, the enzyme ZHD518 significantly reduced the initial concentration of ZEA in the perforated and non-perforated wheat kernels in comparison with controls. Moreover, in vitro incubation of ZHD518 with ZEA showed the presence of two non-estrogenic degradation products of ZEA: hydrolysed zearalenone (HZEA) and decarboxylated hydrolysed ZEA (DHZEA). In addition, the physical pre-treatment led to a reduction in detectable mycotoxin contents in a subset of samples. Overall, this study emphasizes the promising potential of combining physical pre-treatment approaches with biological decontamination solutions in order to address the associated problem of mycotoxin contamination and food waste reduction.

Fe-N co-doped biochar derived from biomass waste triggers peracetic acid activation for efficient water decontamination

In this study, the porous carbon material (FeN-BC) with ultra-high catalytic activity was obtained from waste biomass through Fe-N co-doping. The prominent degradation rate (> 96.8%) of naproxen (NAP) was achieved over a wide pH range (pH 3.0-9.0) in FeN-BC/PAA system. Unlike previously reported iron-based peracetic acid (PAA) systems with •OH or RO• as the dominated reactive species, the degradation of contaminants was attributed to singlet oxygen (1O2) produced by organic radicals (RO•) decomposition, which was proved to be thermodynamically feasible and favorable by theoretical calculations. Combining the theoretical calculations, characteristic and experimental analysis, the synergistic effects of Fe and N were proposed and summarized as follows: i) promoted the formation of extensive defects and Fe0 species that facilitated electron transfer between FeN-BC and PAA and continuous Fe(II) generation; ii) modified the specific surface area (SSA) and the isoelectric point of FeN-BC in favor of PAA adsorption on the catalyst surface. This study provides a strategy for waste biomass reuse to construct a heterogeneous catalyst/PAA system for efficient water purification and reveals the synergistic effects of typical metal-heteroatom for PAA activation.

An innovative Fuller's earth-based film-forming formulation for skin decontamination, through removal and entrapment of an organophosphorus compound, paraoxon-ethyl

Organophosphorus compounds (OPs), such as VX, pose a significant threat due to their neurotoxic and hazardous properties. Skin decontamination is essential to avoid irreversible effects. Fuller's earth (FE), a phyllosilicate conventionally employed in powder form, has demonstrated decontamination capacity against OPs. The aim of this study was to develop a formulation that forms a film on the skin, with a significant OP removal capacity (>95 %) coupled with sequestration capabilities, favorable drying time and mechanical properties to allow for easy application and removal, particularly in emergency context. Various formulations were prepared using different concentrations of polyvinyl alcohol (PVA), FE and surfactants. Their removal and sequestration capacity was tested using paraoxon-ethyl (POX), a chemical that simulates the behavior of VX. Formulations with removal capacity levels surpassing 95 % were mechanically characterized and cell viability assays were performed on Normal Human Dermal Fibroblast (NHDF). The four most promising formulations were used to assess decontamination efficacy on pig ear skin explants. These formulations showed decontamination levels ranging from 84.4 ± 4.7 % to 96.5 ± 1.3 %, which is equivalent to current decontamination methods. These results suggest that this technology could be a novel and effective tool for skin decontamination following exposure to OPs.

Short-duration selective decontamination of the digestive tract infection control does not contribute to increased antimicrobial resistance burden in a pilot cluster randomised trial (the ARCTIC Study)

OBJECTIVE

Selective decontamination of the digestive tract (SDD) is a well-studied but hotly contested medical intervention of enhanced infection control. Here, we aim to characterise the changes to the microbiome and antimicrobial resistance (AMR) gene profiles in critically ill children treated with SDD-enhanced infection control compared with conventional infection control.

DESIGN

We conducted shotgun metagenomic microbiome and resistome analysis on serial oropharyngeal and faecal samples collected from critically ill, mechanically ventilated patients in a pilot multicentre cluster randomised trial of SDD. The microbiome and AMR profiles were compared for longitudinal and intergroup changes. Of consented patients, faecal microbiome baseline samples were obtained in 89 critically ill children. Additionally, samples collected during and after critical illness were collected in 17 children treated with SDD-enhanced infection control and 19 children who received standard care.

RESULTS

SDD affected the alpha and beta diversity of critically ill children to a greater degree than standard care. At cessation of treatment, the microbiome of SDD patients was dominated by Actinomycetota, specifically Bifidobacterium, at the end of mechanical ventilation. Altered gut microbiota was evident in a subset of SDD-treated children who returned late longitudinal samples compared with children receiving standard care. Clinically relevant AMR gene burden was unaffected by the administration of SDD-enhanced infection control compared with standard care. SDD did not affect the composition of the oral microbiome compared with standard treatment.

CONCLUSION

Short interventions of SDD caused a shift in the microbiome but not of the AMR gene pool in critically ill children at the end mechanical ventilation, compared with standard antimicrobial therapy.

Neutralization of ricin toxin on building interior surfaces using liquid decontaminants

Ricin is a highly toxic protein, capable of inhibiting protein synthesis within cells, and is produced from the beans of the Ricinus communis (castor bean) plant. Numerous recent incidents involving ricin have occurred, many in the form of mailed letters resulting in both building and mail sorting facility contamination. The goal of this study was to assess the decontamination efficacy of several commercial off-the-shelf (COTS) cleaners and decontaminants (solutions of sodium hypochlorite [bleach], quaternary ammonium, sodium percarbonate, peracetic acid, and hydrogen peroxide) against a crude preparation of ricin toxin. The ricin was inoculated onto four common building materials (pine wood, drywall joint tape, countertop laminate, and industrial carpet), and the decontaminants were applied to the test coupons using a handheld sprayer. Decontamination efficacy was quantified using an in-vitro cytotoxicity assay to measure the quantity of bioactive ricin toxin extracted from test coupons as compared to the corresponding positive controls (not sprayed with decontaminant). Results showed that decontamination efficacy varied by decontaminant and substrate material, and that efficacy generally improved as the number of spray applications or contact time increased. The solutions of 0.45% peracetic acid and the 20,000-parts per million (ppm) sodium hypochlorite provided the overall best decontamination efficacy. The 0.45% peracetic acid solution achieved 97.8 to 99.8% reduction with a 30-min contact time.

Key topics for making decisions on decorporation terapies

Decorporation therapies increase the excretion of the incorporated material and therefore may reduce the probability of the occurrence of stochastic effects and may avoid deterministic effects in persons internally contaminated with radionuclides. The decision to initiate decorporation therapy should consider the effects of treatment in relation to the benefit provided. The literature presents threshold values above which treatment is recommended. The objective of this work is to collect and summarize recommendations on decorporation therapy. Ten key topics are presented for consideration by a multidisciplinary team when assessing the risk-benefit balance for performing decorporation therapy.

Reactive skin decontamination lotion (RSDL) safety with clinical antiseptics and hemostatic agents

Reactive skin decontamination lotion (RSDL) is a Health Canada approved product used by the Canadian Armed Forces for removal and inactivation of toxic chemicals on skin. Although it is considered very safe when used as directed, questions have been raised regarding whether topical RSDL in the medical setting will react exothermically with antiseptic compounds on the casualty's epidermis that could result in thermal burns. Benchtop experiments were conducted to investigate reactivity of RSDL with various antiseptic compounds or hemostatic agents. Temperature changes were closely monitored in three different volume ratios, 1:10, 1:1, and 10:1 over a time course of 16 minutes. Chlorine based bleaches versus RSDL were included as a positive control and were the only combination that exhibited a significant exothermic reaction capable of causing minor thermal burns. RSDL was also evaluated with antiseptic solution applied to swine epidermal tissue without observation of visual irritation; then in lacerated skeletal muscle tissue which resulted in no measured temperature change. The conclusion of this study is that antiseptics and hemostatic agents can be used as required on a patient decontaminated with RSDL as no exothermic reaction will occur.

Insight into Cu (II) adsorption on pyrochar and hydrochar resultant from Acacia Senegal waste for wastewater decontamination

Acacia Senegal waste (ASW) is remaining biomass following gum Arabic harvesting and has no use mentioned in the literature as of yet. This study aims to convert ASW into valuable biochar via two comparative thermal and hydrothermal techniques, which include pyrochar ASW at 300 °C (PC ASW300) and hydrochar ASW at 180 °C (HC ASW180), respectively, for Cu (II) adsorption from aqueous solutions. SEM-EDS, FTIR, XRD, and XPS were used to characterize the biochar. Adsorption performance was studied as a function of pH, contact time, and adsorbent concentration. Adsorption kinetics were best fit for a pseudo-second-order model. And thermodynamics studies revealed that Cu (II) on biochar was endothermic, spontaneous, and best fitted to the Langmuir isotherm model. Pyrochar adsorption capacity (31.93 mg g-1) was seven times that of hydrochar (5.45 mg g-1). ASW treated with phosphorus (PC H3PO4 and HC H3PO4) prior to the carbonization altered the pore structure and surface functional groups as well (O-P-O, P-CH3, and P-OH) of biochar. It was found that treating with phosphorous acid increased adsorption capacity to 141.7 mg g-1 and 22.24 mg g-1 for PC H3PO4 and HC H3PO4, respectively. The surface functional groups of biochar resulted from lignin, alkaloids, and polysaccharides combined with Cu (II) during the adsorption process via surface complexation accompanied by π-electron interaction and Cu (II) reduction. These findings shed light on the ASW biochar potential as a new green cost-effective adsorbent and drew an insightful understanding of Cu (II) adsorption performance and mechanism. It is concluded that ASW-derived biochar is highly effective and a promising alternative for Cu (II) decontamination from wastewater.

A green approach to efficient soil decontamination using supercritical carbon dioxide and ethanol

As the need for global decommissioning and site remediation of aging and shut-down nuclear power plants continues to grow, it becomes increasingly crucial to efficiently treat contaminated soil while minimizing waste generation. This study explores an innovative soil decontamination approach that utilizes supercritical carbon dioxide (SCCO₂) as the primary solvent, along with ethanol as a co-solvent and specific additives, including a chelate ligand (catechol ligand) and a co-ligand (NEt₄PFOSA). The advantages of SCCO₂, such as its penetration and solubility, coupled with its ability to separate from radioactive waste, are harnessed in this research. The study demonstrates that the combination of SCCO₂, ethanol, and additives significantly enhances decontamination efficiency, particularly for cesium (Cs), strontium (Sr), and uranium (U) contamination. Results indicate that decontamination efficiency varies with soil particle size, with smaller particles presenting greater challenges. This study presents a promising eco-friendly soil decontamination technology using SCCO₂ containing ethanol and specific additives to efficiently reduce radioactive contamination in soil.

The role of decontamination in reducing healthcare-associated infections

Effective decontamination is a vital aspect of infection prevention and control, and has a crucial role in reducing healthcare-associated infections (HCAIs). Various decontamination methods can be used in healthcare settings to ensure that medical devices, equipment and the clinical environment are safe. It is essential for nurses and other healthcare staff to have adequate knowledge of the decontamination methods and infection prevention and control practices required to prevent HCAIs. This article discusses the most common HCAIs, decontamination methods that can be used, and relevant UK legislation, policies and guidance. It also outlines nurses' responsibilities in relation to infection prevention and control and the importance of education and training in this area, with a particular focus on integrating human factors.

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.

Ultraviolet C intensity dependence of decontamination efficiency for pathogens as function of repacked metamaterials with screw channels

A new method for repackaging optical metamaterials formed from quartz spheres (fibers) of various diameters is proposed for ultraviolet C disinfection of infected liquids by pathogens (viruses and bacteria). The main idea of the new equipment is connected with the rotation of a contaminated fluid by screw channels within a metamaterial matrix prepared from UVC fibers/spherical optics, to improve the decontamination efficiency. In demonstration of the viability of this approach, dynamic and static inactivation of Baker's yeast via Ultraviolet C radiation regimes are used in this paper to show the efficacy of decontamination within the screw channels.

TidyTron: Reducing lab waste using validated wash-and-reuse protocols for common plasticware in Opentrons OT-2 lab robots

Every year biotechnology labs generate a combined total of ∼5.5 million tons of plastic waste. As the global bioeconomy expands, biofoundries will inevitably increase plastic consumption in-step with synthetic biology scaling. Decontamination and reuse of single-use plastics could increase sustainability and reduce recurring costs of biological research. However, throughput and variable cleaning quality make manual decontamination impractical in most instances. Automating single-use plastic cleaning with liquid handling robots makes decontamination more practical by offering higher throughput and consistent cleaning quality. However, open-source, validated protocols using low-cost lab robotics for effective decontamination of plasticware-facilitating safe reuse-have not yet been developed. Here we introduce and validate TidyTron: a library of protocols for cleaning micropipette tips and microtiter plates that are contaminated with DNA, E. coli, and S. cerevisiae. We tested a variety of cleaning solutions, contact times, and agitation methods with the aim of minimizing time and cost, while maximizing cleaning stringency and sustainability. We tested and validated these cleaning procedures by comparing fresh (first-time usage) versus cleaned tips and plates for contamination with cells, DNA, or cleaning solutions. We assessed contamination by measuring colony forming units by plating, PCR efficiency and DNA concentration by qPCR, and event counts and debris by flow cytometry. Open source cleaning protocols are available at https://github.com/PlantSynBioLab/TidyTron and hosted on a graphical user interface at https://jbryantvt.github.io/TidyTron/.

A proof-of-principle for decontamination of transplantation kidney through UV-C exposition of the perfusate solution

Kidney transplantation is a common yet highly demanding medical procedure worldwide, enhancing the quality of life for patients with chronic kidney disease. Despite its prevalence, the procedure faces a shortage of available organs, partly due to contamination by microorganisms, leading to significant organ disposal. This study proposes utilizing photonic techniques associated with organ support machines to prevent patient contamination during kidney transplantation. We implemented a decontamination system using ultraviolet-C (UV-C) irradiation on the preservation solution circulating through pigs' kidneys between harvest and implant. UV-C irradiation, alone or combined with ultrasound (US) and Ps80 detergent during ex-vivo swine organ perfusion in a Lifeport® Kidney Transporter machine, aimed to reduce microbiological load in both fluid and organ. Results show rapid fluid decontamination compared to microorganism release from the organ, with notable retention. By including Ps80 detergent at 0.5% during UV-C irradiation 3 log10 (CFU mL-1) of Staphylococcus aureus bacteria previously retained in the organ were successfully removed, indicating the technique's feasibility and effectiveness.

Bacterial Infections After Liver Transplantation and the Role of Oral Selective Digestive Decontamination: A Retrospective Cohort Study

BACKGROUND

Bacterial infections are common after liver transplantation (LT) and cause serious morbidity and mortality. In our center, prolonged selective digestive decontamination (SDD) is the standard of care, which may lead to a reduced number and severity of bacterial infections. The aim of the current study was to investigate bacterial infection rates, the causative pathogens, localization, and the possible influence of SDD within the first year after LT.

METHODS

A retrospective single-center cohort study was performed. Patients within their first year after LT between 2012 and 2017 were included. Patients received SDD for 3 weeks immediately after LT. The type of infection, bacterial subtype, CSI classification, severity, and potential interventions were recorded.

RESULTS

One hundred eighty-six patients were included in the study. Seventy-eight patients (41.9%) had a bacterial infection within the first year after LT. The most common types of infection were cholangitis (25.8%) and secondary infected abdominal fluid collections (25.3%). The most common bacteria were Gram-positive enterococcal- (36.5%) and Gram-negative enterobacterial species (34.2%). 35.5% of the infections occurred within the first month after LT, mainly caused by Gram-positive bacteria (76.7%).

CONCLUSIONS

Cholangitis and infected abdominal fluid are the most common types of infection within one year after LT, mainly caused by enterococcal- and enterobacterial species. Within the first month after LT, infections were mostly caused by Gram-positive bacteria, which could be a consequence of protocol use of SDD. The results can be used for the choice of empirical antibiotic therapy based on the most common types of bacteria and the time frame after LT.

Efficacy of a novel three-step decontamination protocol for titanium-based dental implants: An in vitro and in vivo study

AIM

The aim of the study was to evaluate several mechanical and chemical decontamination methods associated with a newly introduced biofilm matrix disruption strategy for biofilm cleaning and preservation of implant surface features.

MATERIALS AND METHODS

Titanium (Ti) discs were obtained by additive manufacturing. Polymicrobial biofilm-covered Ti disc surfaces were decontaminated with mechanical [Ti curette, Teflon curette, Ti brush, water-air jet device, and Er:YAG laser] or chemical [iodopovidone (PVPI) 0.2% to disrupt the extracellular matrix, along with amoxicillin; minocycline; tetracycline; H2 O2 3%; chlorhexidine 0.2%; NaOCl 0.95%; hydrocarbon-oxo-borate-based antiseptic] protocols. The optimal in vitro mechanical/chemical protocol was then tested in combination using an in vivo biofilm model with intra-oral devices.

RESULTS

Er:YAG laser treatment displayed optimum surface cleaning by biofilm removal with minimal deleterious damage to the surface, smaller Ti release, good corrosion stability, and improved fibroblast readhesion. NaOCl 0.95% was the most promising agent to reduce in vitro and in vivo biofilms and was even more effective when associated with PVPI 0.2% as a pre-treatment to disrupt the biofilm matrix. The combination of Er:YAG laser followed by PVPI 0.2% plus NaOCl 0.95% promoted efficient decontamination of rough Ti surfaces by disrupting the biofilm matrix and killing remnants of in vivo biofilms formed in the mouth (the only protocol to lead to ~99% biofilm eradication).

CONCLUSION

Er:YAG laser + PVPI 0.2% + NaOCl 0.95% can be a reliable decontamination protocol for Ti surfaces, eliminating microbial biofilms without damaging the implant surface.

N95 respirator hybrid decontamination method using Ultraviolet Germicidal Irradiation (UVGI) coupled with Microwave-Generated Steam (MGS)

The Coronavirus Disease 2019 (COVID-19) pandemic has induced a critical supply of personal protective equipment (PPE) especially N95 respirators. Utilizing respirator decontamination procedures to reduce the pathogen load of a contaminated N95 respirator can be a viable solution for reuse purposes. In this study, the efficiency of a novel hybrid respirator decontamination method of ultraviolet germicidal irradiation (UVGI) which utilizes ultraviolet-C (UV-C) rays coupled with microwave-generated steam (MGS) against feline coronavirus (FCoV) was evaluated. The contaminated 3M 1860 respirator pieces were treated with three treatments (UVGI-only, MGS-only, and Hybrid-UVGI + MGS) with variable time. The virucidal activity was evaluated using the TCID50 method. The comparison of decontamination efficiency of the treatments indicated that the hybrid method achieved at least a pathogen log reduction of 4 logs, faster than MGS and UVGI. These data recommend that the proposed hybrid decontamination system is more effective comparatively in achieving pathogen log reduction of 4 logs.

Bacterial Decontamination of Water-Containing Objects Using Piezoelectric Direct Discharge Plasma and Plasma Jet

Cold atmospheric plasma has become a widespread tool in bacterial decontamination, harnessing reactive oxygen and nitrogen species to neutralize bacteria on surfaces and in the air. This technology is often employed in healthcare, food processing, water treatment, etc. One of the most energy-efficient and universal methods for creating cold atmospheric plasma is the initiation of a piezoelectric direct discharge. The article presents a study of the bactericidal effect of piezoelectric direct discharge plasma generated using the multifunctional source "CAPKO". This device allows for the modification of the method of plasma generation "on the fly" by replacing a unit (cap) on the working device. The results of the generation of reactive oxygen and nitrogen species in a buffer solution in the modes of direct discharge in air and a plasma jet with an argon flow are presented. The bactericidal effect of these types of plasma against the bacteria E. coli BL21 (DE3) was studied. The issues of scaling the treatment technique are considered.

Effectiveness of mechanical and chemical decontamination methods for the treatment of dental implant surfaces affected by peri-implantitis: A systematic review and meta-analysis

OBJECTIVE

To assess which decontamination method(s) used for the debridement of titanium surfaces (disks and dental implants) contaminated with bacterial, most efficiently eliminate bacterial biofilms.

MATERIAL AND METHODS

A systematic search was conducted in four electronic databases between January 1, 2010 and October 31, 2022. The search strategy followed the PICOS format and included only in vitro studies completed on either dental implant or titanium disk samples. The assessed outcome variable consisted of the most effective method(s)-chemical or mechanical- removing bacterial biofilm from titanium surfaces. A meta-analysis was conducted, and data was summarized through single- and multi-level random effects model (p < .05).

RESULTS

The initial search resulted in 5260 articles after the removal of duplicates. After assessment by title, abstract, and full-text review, a total of 13 articles met the inclusion criteria for this review. Different decontamination methods were assessed, including both mechanical and chemical, with the most common method across studies being chlorhexidine (CHX). Significant heterogeneity was noted across the included studies. The meta-analyses only identified a significant difference in biofilm reduction when CHX treatment was compared against PBS. The remaining comparisons did not identify significant differences between the various decontamination methods.

CONCLUSIONS

The present results do not demonstrate that one method of decontamination is superior in eliminating bacterial biofilm from titanium disk and implant surfaces.

aPDI meets PPE: photochemical decontamination in healthcare using methylene blue-where are we now, where will we go?

Personal protective equipment (PPE) reuse, first recommended in the context of the SARS-CoV-2 pandemic, can mitigate shortages in crisis situations and can greatly reduce the environmental impact of typically single-use PPE. Prior to safe reuse, PPE must be sanitized and contaminating pathogens-in current circumstances viruses in particular-must be inactivated. However, many established decontamination procedures are not equitable and remain unavailable in low-resource settings. In mid-2020, an interdisciplinary consortium of researchers first studied the potential of implementing cheap and easy-to-use antimicrobial photodynamic inactivation (aPDI) using methylene blue as photosensitizer to decontaminate face masks and filtering facepiece respirators. In this perspective piece, we describe the development of this novel method, discuss recent advances, and offer insights into how equitable PPE decontamination via methylene blue-based aPDI may be integrated into circular economy policies in the healthcare sector.

Evaluation of the effects of wiping decontamination for filter cartridges of elastomeric half-mask respirators (EHMRs)

BACKGROUND

A major concern among health care experts is a shortage of N95 filtering facepiece respirators during a pandemic. If the supply of N95 filtering facepiece respirators becomes limited, reusable elastomeric half-mask respirators (EHMRs) may be used to protect health care workers. The focus of this study was to evaluate the effects on the filter performance of wiping decontamination for EHMR P100 filter cartridges.

METHODS

The filter cartridge exterior of EHMR Honeywell, Moldex, and Mine Safety Appliance (MSA) models was wiped using quaternary ammonium and sodium hypochlorite wipes. These filter cartridge properties were assessed including observational analysis and filter performance tests. These wiping and assessing procedures were repeated after each set of wiping cycles (50, 100, 150, 200, and 400 cycles) to determine the effects of wiping decontamination.

RESULTS

For sodium hypochlorite wipes, Honeywell, Moldex, and MSA models passed the National Institute for Occupational Safety and Health (NIOSH) liquid particulate penetration criteria for all wiping cycles from 50 to 400 (penetrations<0.014%). For quaternary ammonium wipes, filter penetrations of Moldex failed (penetrations>0.03%) after 150 cycles, while the filter penetrations of Honeywell and MSA passed for all wiping cycles (penetrations ≤0.013%).

CONCLUSIONS

Wiping decontamination methods using sodium hypochlorite and quaternary ammonium wipes could be considered promising decontamination candidates for Honeywell, Moldex, and MSA reuse, except for the wiping number selection for Moldex (<150 cycles) when using the quaternary ammonium wipe.

Anatomical three-dimensional model with peri-implant defect for in vitro assessment of dental implant decontamination

OBJECTIVES

Access to the implant surface plays a significant role in effective mechanical biofilm removal in peri-implantitis treatment. Mechanical decontamination may also alter the surface topography of the implant, potentially increasing susceptibility to bacterial recolonization. This in vitro study aimed to evaluate a newly developed, anatomically realistic, and adaptable three-dimensional (3D)printed model with a peri-implant bone defect to evaluate the accessibility and changes of dental implant surfaces after mechanical decontamination treatment.

MATERIAL AND METHODS

A split model of an advanced peri-implant bone defect was prepared using 3D printing. The function of the model was tested by mechanical decontamination of the exposed surface of dental implants (Standard Implant Straumann AG) coated with a thin layer of colored occlusion spray. Two different instruments for mechanical decontamination were used. Following decontamination, the implants were removed from the split model and photographed. Image analysis and fluorescence spectroscopy were used to quantify the remaining occlusion spray both in terms of area and total amount, while scanning electron microscopy and optical profilometry were used to analyze alteration in the implant surface morphology.

RESULTS

The 3D model allowed easy placement and removal of the dental implants without disturbing the implant surfaces. Qualitative and quantitative assessment of removal of the occlusion spray revealed differences in the mechanism of action and access to the implant surface between tested instruments. The model permitted surface topography analysis following the decontamination procedure.

CONCLUSION

The developed 3D model allowed a realistic simulation of decontamination of implant surfaces with colored occlusion spray in an advanced peri-implant defect. 3D printing allows easy adaptation of the model in terms of the shape and location of the defect. The model presents a valuable tool for in vitro investigation of the accessibility and changes of the implant surface after mechanical and chemical decontamination.

Decontamination of a robot used to reprocess reusable surgical instruments

BACKGROUND

Using robots to handle medical devices in the decontamination area of the Central Sterile Supply Department (CSSD) can reduce risks and address staff shortages. The gripper design must allow reliable cleaning using standard CSSD procedures to avoid build-up of biofilms and possible cross-contamination between different instrument trays and the gripper's functionality. This study explores the design of the robot's gripper regarding cleanability, aiming to determine whether successful cleaning can be achieved even after prolonged drying for a working shift of 8 h.

METHODS

We optimized a gripper for cleanability and used it to assess the spread of different test soils depending on different forms of motion. Subsequently, we analysed the cleanability using sheep's blood as test soil, reprocessing the gripper in different assembly configurations after 4 and 8 h of drying, and measuring residual protein.

FINDINGS

Based on our investigations, we documented the spread of contamination depending on the type of motion of the gripper's components. Sheep's blood exhibited the highest dispersion among the test soils, permeating through thin crevices. Importantly, all samples displayed residual protein levels below the warning threshold, irrespective of drying time and gripper disassembly or cleaning position. Cleaning in a device-specific optimized position achieved results comparable to cleaning the disassembled individual components.

CONCLUSIONS

These findings indicate that cleaning even after one working shift of 8 h and without the labour-intensive disassembly of the gripper is feasible, supporting the future use of robots to handle contaminated medical devices in the CSSD decontamination area.

A review on sterilization methods of environmental decontamination to prevent the coronavirus SARS-CoV-2 (COVID-19 virus): A new challenge towards eco-friendly solutions

In recent years, the COVID-19 pandemic is currently wreaking havoc on the planet. SARS-CoV-2, the Severe Acute Respiratory Syndrome Coronavirus, is the current term for this outbreak. Reports about this novel coronavirus have been presented since the pandemic's breakout, and they have demonstrated that it transmits rapidly from person to person, primarily by droplets in the air. Findings have illustrated that SARS-CoV-2 can survive on surfaces from hours to days. Therefore, it is essential to find practical solutions to reduce the virus's impact on human health and the environment. This work evaluated common sterilization methods that can decontaminate the environment and items. The goal is that healthcare facilities, disease prevention organizations, and local communities can overcome the new challenge of finding eco-friendly solutions. Further, a foundation of information encompassing various sterilization procedures and highlighting their limits to choose the most appropriate method to stop disease-causing viruses in the new context has been presented. The findings of this crucial investigation contribute to gaining insight into the comprehensive sterilization approaches against the coronavirus for human health protection and sustainable environmental development.

Selective digestive tract decontamination to prevent healthcare associated infections in critically ill children: the PICNIC multicentre randomised pilot clinical trial

Healthcare-associated infections (HCAIs) are a major cause of morbidity and mortality in critically ill children. Data from adult studies suggest Selective Decontamination of the Digestive tract (SDD) may reduce the incidence of HCAIs and improve survival. There are no data from randomised clinical trials in the paediatric setting. An open label, parallel group pilot cRCT and mixed-methods perspectives study was conducted in six paediatric intensive care units (PICUs) in England. Participants were children (> 37 weeks corrected gestational age, up to 16 years) requiring mechanical ventilation expected to last for at least 48 h. Sites undertook standard care for a period of 9 weeks and were randomised into 3 sites which continued standard care and 3 where SDD was incorporated into infection control practice for eligible children. Interviews and focus groups were conducted for parents and staff working in PICU. 434 children fulfilled eligibility criteria, of whom 368 (85%) were enrolled. This included 207 in the baseline phase (Period One) and 161 in the intervention period (Period Two). In sites delivering SDD, the majority (98%) of children received at least one dose of SDD and of these, 68% commenced within the first 6 h. Whilst admission swabs were collected in 91% of enrolled children, consent for the collection of additional swabs was low (44%). Recruited children were representative of the wider PICU population. Overall, 3.6 children/site/week were recruited compared with the potential recruitment rate for a definitive cRCT of 3 children/site/week, based on data from all UK PICUs. Parents (n = 65) and staff (n = 44) were supportive of the aims of the study, suggesting adaptations for a larger definitive trial including formulation and administration of SDD paste, approaches to consent and ecology monitoring. Stakeholders identified preferred clinical outcomes, focusing on complications of critical illness and quality-of-life. A definitive cRCT in SDD to prevent HCAIs in critically ill children is feasible but should include adaptations to ecology monitoring along with the dosing schedule and packaging into a paediatric specific format. A definitive study is supported by the findings with adaptations to ecology monitoring and SDD administration.Trial Registration: ISRCTN40310490 Registered 30/10/2020.

Effect of chemical and electrochemical decontamination protocols on single and multiple-used healing abutments: A comparative analysis of contact surface area, micro-gap, micro-leakage, and surface topography

INTRODUCTION

Although the combined use of chemical and electrochemical decontamination protocols can completely remove contaminants from the surfaces of one-time used healing abutments (HAs), their effectiveness in multiple-used HAs remains unknown. We aimed to investigate the effect of reused HAs frequency on the implant-HA contact surface area, micro-gap, microleakage, and surface topography following chemical and combined chemical and electrochemical decontamination protocols.

METHODS

Ninety bone level titanium implants were assembled with 90 bone level HAs, in which 80 contaminated HA samples were collected from human participants. The retrieved HAs were randomly divided into two groups according to the cleaning protocol: ultrasonication with 5.25% NaOCl solution for 15 min and steam autoclaving (group I); ultrasonication with 5.25% NaOCl solution for 15 min, followed by electrochemical cleaning and steam autoclaving (group II). The control group (group III) comprised 10 new unused HAs. The cleaning protocol was applied after each insertion as follows: (a) single-use and cleaning, (b) double-use and double cleaning cycles, (c) triple-use and triple cleaning cycles, and (d) more than triple-use and more than triple cleaning cycles. The contact surface area and micro-gap were assessed with micro-computed tomography scanning technique, microleakage test using 2% methylene blue staining, surface morphology with scanning electron microscopy, and surface elemental composition with energy-dispersive X-ray spectroscopy analysis.

RESULTS

Group Id exhibited the smallest contact surface area. The values of the micro-gap volumes and microleakage were significantly different (p < 0.001) in the descending order of Id > Ic > Ib > IId > Ia, IIa, and III. Morphological evaluation of Groups IIa, IIb, and IIc revealed that residual biological debris was optimally removed without altering their surface properties.

CONCLUSIONS

Chemical and electrochemical decontamination protocols are more effective than NaOCl cleaning methods, particularly for multiple consecutive uses with better decontamination levels, which decreases micro-gap volume and microleakage without surface alterations. Although the use of combined decontamination protocols for the contact surface area at the implant-HA interface showed comparable results with the control, change in the contact surface area was observed following the NaOCl cleaning methods. Therefore, titanium HA reuse can be considered in multiple times, if they are cleaned and sterilized using combined chemical and electrochemical decontamination protocols.

Moist heat as a promising method to decontaminate N95 masks: A large scale clinical study comparing four decontamination modalities-moist heat, steam, ultraviolet-C irradiation, and hydrogen peroxide plasma

BACKGROUND

Early in the COVID-19 pandemic, there was a global shortage of masks. Although mask reprocessing was practiced, no clinical study has assessed systematically the impact of repeated cycles of wear and decontamination on the integrity of N95 filtering facepiece respirators (FFRs).

METHODS

We evaluated mask fit assessed by qualitative respirator fit test (QRFT) after each cycle of wear and decontamination, as well as four measures of mask integrity-bacterial filtration efficacy, particle filtration efficacy, differential pressure, and splash resistance through five cycles of wear and decontamination using one of the four modalities (moist heat, steam, ultraviolet-C irradiation, and hydrogen peroxide plasma).

RESULTS

A total of 60.6% (hydrogen peroxide plasma) to 77.5% (moist heat) of the FFRs passed five cycles of wear and decontamination, as assessed by the wearers passing QRFT all five times. Moist heat-decontaminated FFRs retained all technical measures of integrity through all five cycles.

CONCLUSIONS

This is the first large-scale study to assess systematically the impact (clinically and quantitatively) on N95 FFR integrity of repeated cycles of wearing followed by decontamination. Our results suggest that moist heat is a promising method for decontaminating N95 FFRs. Performing QRFT after every cycle of wear and decontamination ensures wearer safety. Although there is currently no mask shortage, reprocessing may reduce medical waste and improve sustainability.

Evaluating Firefighter On-Scene Decontamination Practices Using a National Fire Records Management System

OBJECTIVE

This study describes firefighters' on-scene decontamination procedure use post-working fire and frequency of adherence to best practice.

METHODS

This retrospective analysis of working fires was conducted using records from the ESO Data Collaborative (Austin, TX) national research database from January 1, 2021, to December 31, 2021. Documentation of decontamination procedures was examined among records with smoke or combustion products exposure. Firefighter and incident characteristics were evaluated. Descriptive statistics and univariable odds ratios were calculated.

RESULTS

Among the 31,281 firefighters included in the study, 8.0% documented a fire-related exposure. Of those, 82% performed at least one on-scene decontamination procedure; 5% documented all decontamination procedures defined as best practices. The odds of documenting any decontamination procedure were significantly decreased among firefighters responding to incidents in rural areas compared with urban areas (odds ratio, 0.70).

CONCLUSIONS

Fire personnel may not be taking all necessary decontamination steps post-working fires.

Studies on the optimization of decontamination protocol for surfaces contaminated with cytotoxic drugs in PIVAS

PURPOSE

The goal of this study was to create a cleaning procedure by comparing the performance of six different cleaning methods on the surfaces in pharmacy intravenous admixture service (PIVAS) work area.

METHOD

A stainless steel plate was simulating contaminated by gemcitabine, cyclophosphamide, epirubicin, etoposide, and paclitaxel, which was then dried and cleaned by per current cleaning protocols. The residues were collected and quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Based on the most appropriate cleaning protocol, three cleaning variables were optimized: (1) use of dry gauze after cleaning agent application; (2) cleaning paths (inside-out vs. outside-in); (3) cleaning times (once or twice). Best conditions were tested with real samples from a hospital PIVAS.

RESULTS

This 10-2 M sodium dodecyl sulfate (SDS) and dry gauze cleaning protocol increases cleaning efficiency as well as saves time. Different from the traditional cleaning manner, we found that cleaning from outside to inside can not only improve the cleaning efficiency but also overcome the uneven distribution of drug residues caused by cleaning action. When simulating contamination at a high dose (4 mg/mL) level, it was found that the decontamination efficacy increased with repeating one more time.

CONCLUSION

The 10-2 M SDS and dry gauze cleaning protocol could obtain the best cleaning effect. The success of cytotoxic drug decontamination is determined not only by the cleaning solution, but also by the cleaning route and frequency. Compared with the traditional cleaning manner, there was a significant reduction in the contamination levels in the PIVAS work area after the cleaning protocol with 10-2 M SDS and dry gauze.

A do-it-yourself test protocol using commercial Bacillus atrophaeus spores to evaluate the effectiveness of ultraviolet-C light room-decontamination devices

We developed a do-it-yourself test protocol using commercial Bacillus atrophaeus spores to assess the efficacy of ultraviolet-C (UV-C) light room-decontamination devices. Overall, 4 UV-C devices reduced B. atrophaeus by ≥3 log10 colony-forming units in 10 minutes, whereas a smaller device required 60 minutes. Of 10 in-use devices, only 1 was ineffective.

Skin decontamination of Carfentanil in vitro

Skin decontamination of Chemical Biological Radioactive and Nuclear (CBRN) materials involves the timely and effective removal of the contaminants from the skin surface. The current work evaluated Fuller's Earth & The Reactive Skin Decontaminant Lotion Kit (RSDL®) to investigate whether they were as efficacious against free base Carfentanil skin contamination as they are against chemical warfare agents. The in vitro methodology used allowed for evaluation of decontamination regimens as specified by the decontaminant manufacturer rather than as an application of a bolus dose left in situ for the study duration. A selection of novel decontaminants, including Dermal Decontamination Gel (DDGel), Trivorex®, itaconic acid (IA), N,N'-methylenebisacrylamide (MBA), 2-trifluoromethylacrylic acid (TFMAA) and NanoSan Sorb were also tested for efficacy. All the evaluated decontaminants were successful at removing the majority of the Carfentanil skin surface contamination. The current work has shown that the Fuller's Earth decontamination kit, removes as much (or more) free base carfentanil from the skin surface in comparison to other products tested in this study series.

Safety of troclosene sodium solution in decontamination of wounds: A prospective clinical and laboratory study

Debate persists regarding the safety of hypochlorite-containing solutions in the decontamination of infected wounds. In 2006, the Israeli Ministry of Health withdrew licensing approval for troclosene sodium as a wound irrigation solution. The aim of this prospective clinical and laboratory study was to investigate the safety of troclosene sodium solution for decontamination of infected wounds. Troclosene sodium solution was used to treat 30 patients with 35 infected skin wounds of various etiologies and body areas, over a treatment period of 8 days. Data were gathered according to a prospectively designed protocol including general findings, wound-specific observations on Day 1 and Day 8 and laboratory parameters on Day 1 and Day 8. Wound swabs and tissue biopsy for culture were taken on Day 1 and Day 8. Statistical analysis was executed. Tests were 2-sided and p values of <0.05 were considered statistically significant. Eighteen males and 12 females, with 35 infected skin wounds were enrolled. There were no adverse clinical events. No significant changes were observed in general clinical observations. Statistically significant improvements were observed in: pain (p < 0.0001); edema (p < 0.0001); area of wound covered by granulation tissue (p < 0.0001); exudate (p < 0.0001); and erythema (p = 0.002). Prior to treatment, bacteria were demonstrated on microscopy or on culture in 90% of wound samples. On Day 8, this frequency reduced to 40%. There were no abnormal laboratory tests. Serum sodium concentration increased significantly between Day 1 and Day 8, whilst serum concentration of urea and concentrations of thrombocytes, leucocytes and neutrophils showed statistically significant reductions, but all values remained within normal laboratory ranges throughout the study period. Troclosene sodium solution is clinically safe in the management of infected wounds. These findings were presented to the Israel Ministry of Health and as a result, troclosene sodium was re-approved and licensed for decontamination of infected wounds in Israel.

Developing a Decision-making Tool for Agricultural Surface Water Decontamination Using Ultraviolet-C Light

Ultraviolet-C (UV-C) light-assisted water treatment systems are an increasingly investigated alternative to chemical sanitizers for agricultural surface water decontamination. However, the relatively high concentration of particulate matter in surface water is a major challenge to expanding its application in the production of fresh produce. The objective of this project was to test the efficacy of two commercial UV-C devices to reduce the microbial risk of agricultural water in order to develop a web application to assist growers in decision-making related to the on-farm implementation of UV-C technologies for agricultural water treatment. An on-farm study using three agricultural water sources was performed to determine the microbial reduction efficacy of a low power, low flow (LP/LF; 1-9 gallons per minute (GPM), 1.34-gallon capacity) and a high powered, high flow (HP/HF; 1-110 GPM, 4.75-gallon capacity) device at flow rates of 6, 7, and 9 GPM. A threshold of 30% UVT for the HP/HF device was observed, wherein lower water transmissibility significantly impacted microbial inactivation. Although less effective at lower %UVT, the LP/LF device costs less to install, maintain, and operate. The observations were used to design an online tool for growers to calculate the predicted reduction of generic Escherichia coli using either device based on the %UVT of their water source. However, because this study utilized an exploratory and proof-of-concept approach, the experimental flow rates were limited to reflect the capacities of the smaller unit (9 GPM) for direct comparison to the larger unit. Thus, the preliminary model and tool are largely limited to the experimental conditions. Yet, these results of this study demonstrate the utility of UV-C light in reducing the microbial risk of agricultural water, and future studies using different UV-C devices and higher flow rates will expand the use of the decision-making tool.

Evaluation of Decontamination Potential of Wet Wipes Against Microbial Contamination of Chinese Spacecraft Materials

Abstract There are many kinds of microorganisms that inhabit the environment of manned space stations. Wet wipes are a common tool used in space stations to clean and reduce microorganisms on surfaces. Here, we compared the performance of five types of wipes used by the Chinese Space Station (CSS) on orbit before 2021 in terms of microbial decontamination. In previous studies, we found that Bacillus sp. TJ-1-1 and Staphylococcus sp. HN-5 were the most abundant microorganisms in the assembly environment of the CSS. In this study, we used these two bacteria to build different microbial load models to represent the occurrence and non-occurrence of microbial outbreaks in the on-orbit CSS. The results show that the number of microorganisms that can be removed when wiping the surface with high microbial load by wet wipes was higher than that when wiping the surface with low microbial load. For on-orbit daily cleaning and keeping the microbial population within the regulation concentration range, it is suitable to use two pure water wipes per 100 cm2. When the number of microorganisms increases to a degree where astronauts can see the colonies with their naked eyes, the best way to eliminate the problem is to wipe them thoroughly and repeatedly with at least four quaternary ammonium-based wipes every 100 cm2.

Microbial decontamination assisted by ultrasound-based processing technologies in food and model systems: A review

Ultrasound (US) technology is recognized as one of the emerging technologies that arise from the current trends for improving nutritional and organoleptic properties while providing food safety. However, when applying the US alone, higher power and longer treatment times than conventional thermal treatments are needed to achieve a comparable level of microbial inactivation. This results in risks, damaging food products' composition, structure, or sensory properties, and can lead to higher processing costs. Therefore, the US has often been investigated in combination with other approaches, like heating at mild temperatures and/or treatments at elevated pressure, use of antimicrobial substances, or other emerging technologies (e.g., high-pressure processing, pulsed electric fields, nonthermal plasma, or microwaves). A combination of US with different approaches has been reported to be less energy and time consuming. This manuscript aims to provide a broad review of the microbial inactivation efficacy of US technology in different food matrices and model systems. In particular, emphasis is given to the US in combination with the two most industrially viable physical processes, that is, heating at mild temperatures and/or treatments at elevated pressure, resulting in techniques known as thermosonication, manosonication, and manothermosonication. The available literature is reviewed, and critically discussed, and potential research gaps are identified. Additionally, discussions on the US's inactivation mechanisms and lethal effects are included. Finally, mathematical modeling approaches of microbial inactivation kinetics due to US-based processing technologies are also outlined. Overall, this review focuses only on the uses of the US and its combinations with other processes relevant to microbial food decontamination.

Cleaning methods for dental instruments

It is essential to ensure that reusable dental instruments are scrupulously clean as a first step in the decontamination process. Any residual soil on the surface of equipment creates a risk that will prevent steam, generated during sterilisation, from condensing on the surface of the instrument and raising the temperature to that required to ensure sterilisation. Further, most microorganisms will struggle to attach to the surface of a clean instrument. Adherence of microorganisms to the surface of an instrument that is contaminated with organic soil or the irregular surface of residual dental materials is likely to be greatly enhanced. It is therefore important to ensure that residual dental materials are removed from the surface of instruments, at the point of use, before they are allowed to set.It is also important to ensure that the methods used to clean dental equipment do not damage the instrument. Any method that has the potential to scratch the surface of an instrument and therefore make it more difficult to clean should be avoided. Aggressive cleaning can lead to removal of the passivation layer, the chromium-rich layer that prevents corrosion occurring, formed on the surface of instruments made from stainless steel. If corrosion forms on the surface of an instrument, the surface becomes roughened and possibly stained. Surface staining can then be difficult to differentiate from other stains or marks caused by retained biological soil. Corrosion on the surface of an instrument will make the effective cleaning of the surface more difficult and therefore corroded or stained instruments should be discarded.

Field trial assessing the antimicrobial decontamination efficacy of gaseous ozone in a public bus setting

The widespread COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) necessitated measures aimed at preventing the spread of SARS-CoV-2. To mitigate the risk of fomite-mediated transmission, environmental cleaning and disinfection regimes have been widely implemented. However, conventional cleaning approaches such as surface wipe downs can be laborious and more efficient and effective disinfecting technologies are needed. Gaseous ozone disinfection is one technology which has been shown to be effective in laboratory studies. Here, we evaluated its efficacy and feasibility in a public bus setting, using murine hepatitis virus (a related betacoronavirus surrogate) and the bacteria Staphylococcus aureus as test organisms. An optimal gaseous ozone regime resulted in a 3.65-log reduction of murine hepatitis virus and a 4.73-log reduction of S. aureus, and decontamination efficacy correlated with exposure duration and relative humidity in the application space. These findings demonstrated gaseous ozone disinfection in field settings which can be suitably translated to public and private fleets that share analogous characteristics.

Chemical decontamination of foods using non-thermal plasma-activated water

The presence of chemical contaminants in foods and agricultural products is one of the major safety issues worldwide, posing a serious concern to human health. Nonthermal plasma (NTP) containing richly reactive oxygen and nitrogen species (RONS) has been trialed as a potential decontamination method. Yet, this technology comes with multiple downsides, including adverse effects on the quality of treated foods and limited exposure to entire surfaces on samples with hard-to-reach spots, further hindering real-life applications. Therefore, plasma-activated water (PAW) has been recently developed to facilitate the interactions between RONS and contaminant molecules in the liquid phase, allowing a whole surface treatment with efficient chemical degradation. Here, we review the recent advances in PAW utilized as a chemical decontamination agent in foods. The reaction mechanisms and the main RONS contributors involved in the PAW-assisted removal of chemical contaminants are briefly outlined. Also, the comprehensive effects of these treatments on food qualities (chemical and physical characteristics) and toxicological evaluation of PAW (in vitro and in vivo) are thoroughly discussed. Ultimately, we identified some current challenges and provided relevant suggestions, which can further promote PAW research for real-life applications in the future.

Effective remediation and decontamination of organophosphorus compounds using enzymes: From rational design to potential applications

Organophosphorus compounds (OPs) have been widely used in agriculture for decades because of their high insecticidal efficiency, which maintains and increases crop yields worldwide. More importantly, OPs, as typical chemical warfare agents, are a serious concern and significant danger for military and civilian personnel. The widespread use of OPs, superfluous and unreasonable use, has caused great harm to the environment and food chain. Developing efficient and environmentally friendly solutions for the decontamination of OPs is a long-term challenge. Microbial enzymes show potential application as natural and green biocatalysts. Thus, utilizing OP-degrading enzymes for environmental decontamination presents significant advantages, as these enzymes can rapidly hydrolyze OPs; are environmentally friendly, nonflammable, and noncorrosive; and can be discarded safely and easily. Here, the properties, structure and catalytic mechanism of various typical OP-degrading enzymes are reviewed. The methods and effects utilized to improve the expression level, catalytic performance and stability of OP-degrading enzymes were systematically summarized. In addition, the immobilization of OP-degrading enzymes was explicated emphatically, and the latest progress of cascade reactions based on immobilized enzymes was discussed. Finally, the latest applications of OP-degrading enzymes were summarized, including biosensors, nanozyme mimics and medical detoxification. This review provides guidance for the future development of OP-degrading enzymes and promotes their application in the field of environmental bioremediation and medicine.

Occurrence of aflatoxins in water and decontamination strategies: A review

Aflatoxins are highly carcinogenic metabolites produced by some Aspergillus species and are the most prevalent mycotoxins. Although aflatoxins are commonly synthesized during fungal colonization in preharvest maize, cereals, and nuts, they can be transported by rainfall to surface water and are a common toxin found in wastewater from some food industries. Here, the occurrence of aflatoxins in bodies of water is reviewed for the first time, along with the decontamination methods. Aflatoxins have been detected in surface, wastewater and drinking water, including tap and bottled water. The specific sources of water contamination remain unclear, which is an important gap that must be addressed in future research. Two main kinds of decontamination methods have been reported, including degradation and adsorption. The best degradation rates were observed using gamma and UV irradiations, oxidoreductases and ozone, while the best adsorption abilities were observed with minerals, polyvinyl alcohol, durian peel and activated carbon. Synthetic polymers could be used as membranes in pipes to remove aflatoxins in water flows. Although most decontamination methods were screened using AFB₁, the other commonly found aflatoxins were not used in the screenings. Overall, the occurrence of aflatoxins in water could be a significant emerging public health concern largely ignored by local and international legislation. Numerous advances have been reported for the decontamination of aflatoxins in water; however, there is still a long way to go to put them into practice.

The effectiveness of phototherapy for surface decontamination against SARS-Cov-2. A systematic review

COVID-19 appeared in December 2019, needing efforts of science. Besides, a range of light therapies (photodynamic therapy, ultraviolet [UV], laser) has shown scientific alternatives to conventional decontamination therapies. Investigating the efficacy of light-based therapies for environment decontamination against SARS-CoV2, a PRISMA systematic review of Phototherapies against SARS-CoV or MERS-CoV species discussing changes in viral RT-PCR was done. After searching MEDLINE/PubMed, EMBASE, and Literatura Latino-Americana e do Caribe em Ciências da Saúde we have found studies about cell cultures irradiation (18), blood components irradiation (10), N95 masks decontamination (03), inanimate surface decontamination (03), aerosols decontamination (03), hospital rooms irradiation (01) with PDT, LED, and UV therapy. The best quality results showed an effective low time and dose UV irradiation for environments and inanimate surfaces without human persons as long as the devices have safety elements dependent on the surfaces, viral charge, humidity, radiant exposure. To interpersonal contamination in humans, PDT or LED therapy seems very promising and are encouraged.

Challenges and future opportunities to unlock the critical supply chain of personal and protective equipment (PPE) encompassing decontamination and reuse under emergency use authorization (EUA) conditions during the COVID-19 pandemic: Through a reflective circularity and sustainability lens

Severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2), and the resulting coronavirus disease (COVID-19), was declared a public health emergency of global concern by the World Health Organization (WHO) in the early months of 2020. There was a marked lack of knowledge to inform national pandemic response plans encompassing appropriate disease mitigation and preparation strategies to constrain and manage COVID-19. For example, the top 16 "most cited" papers published at the start of the pandemic on core knowledge gaps collectively constitute a staggering 29,393 citations. Albeit complex, appropriate decontamination modalities have been reported and developed for safe reuse of personal and protective equipment (PPE) under emergency use authorization (EUA) where critical supply chain shortages occur for healthcare workers (HCWs) caused by the COVID-19 pandemic. Commensurately, these similar methods may provide solutions for the safe decontamination of enormous volumes of PPE waste promoting opportunities in the circular bioeconomy that will also protect our environment, habitats and natural capital. The co-circulation of the highly transmissive mix of COVID-19 variants of concern (VoC) will continue to challenge our embattled healthcare systems globally for many years to come with an emphasis placed on maintaining effective disease mitigation strategies. This viewpoint article addresses the rationale and key developments in this important area since the onset of the COVID-19 pandemic and provides an insight into a variety of potential opportunities to unlock the long-term sustainability of single-use medical devices, including waste management.

Evaluation of steam heat as a decontamination approach for SARS-CoV-2 when applied to common transit-related materials

AIMS

The purpose of this study was to evaluate the efficacy of steam heat for inactivation of SARS-CoV-2 when applied to materials common in mass transit installations.

METHODS AND RESULTS

SARS CoV-2 (USA-WA1/2020) was resuspended in either cell culture media or synthetic saliva, inoculated (∼1 × 106 TCID50) onto porous and nonporous materials and subjected to steam inactivation efficacy tests as either wet or dried droplets. The inoculated test materials were exposed to steam heat ranging from 70°C to 90°C. The amount of infectious SARS-CoV-2 remaining after various exposure durations ranging from 1 to 60 s was assessed. Higher steam heat application resulted in higher inactivation rates at short contact times. Steam applied at 1-inch distance (∼90°C at the surface) resulted in complete inactivation for dry inoculum within 2 s of exposure (excluding two outliers of 19 test samples at the 5-s duration) and within 2-30 s of exposure for wet droplets. Increasing the distance to 2 inches (∼70°C) also increased the exposure time required to achieve complete inactivation to 15 or 30 s for materials inoculated with saliva or cell culture media, respectively.

CONCLUSIONS

Steam heat can provide high levels of decontamination (>3 log reduction) for transit-related materials contaminated with SARS-CoV-2 using a commercially available steam generator with a manageable exposure time of 2-5 s.

Combined effect of atmospheric gas plasma and UVA light: A sustainable and green alternative for chemical decontamination and microbial inactivation of fish processing water

The simultaneous use of UVA light irradiation coupled with low energy cold plasma generated by a dielectric barrier discharge prototype, results in significant enhancement of efficiency of the integrated process with respect to the sole plasma treatment. This effect has been demonstrated both on microbial inactivation of a food-borne pathogen, i.e. Listeria monocytogenes, and on the degradation of a compound of biological origin such as phenylalanine. In the latter case, the analysis of its reaction intermediates and the spectroscopic identification and quantification of peroxynitrites, allowed to propose mechanistic hypotheses on the nature of the observed synergistic effects. Moreover, it has been demonstrated that the process does not affect the quality of trout fillets, indicating its suitability as a chlorine-free, green, and sustainable tool for the decontamination of fish processing water.

Passenger vehicle interior decontamination by low concentration hydrogen peroxide vapor following a wide area biological contamination incident

AIMS

To assess low concentration hydrogen peroxide (LCHP) (H2O2) vapor dispersed with a home humidifier for its ability to decontaminate vehicle interiors contaminated with Bacillus anthracis surrogate Bacillus atrophaeus spores.

METHODS AND RESULTS

Efficacy of a vaporized 3% H2O2 solution was evaluated for liquid volumes, on/off vehicle heating, ventilation, and air conditioning (HVAC) system operations, and temperatures that ranged from 5 to 27°C. Survival of the spores was assessed by quantification of remaining viable spores with efficacy quantified in terms of mean log10 reduction. Decontamination efficacy after the 6-day dwell time increased when the 3% H2O2 liquid volume was doubled, increasing from 4-of-10 to 10-of-10 nondetects (zero colonies counted using standard dilution and filter plating) inside the vehicle cabin. Recirculating cabin air through the HVAC system during decontamination decreased efficacy to 6-of-10 non-detects. While no 6-log10 reduction in viable spores was observed on the cabin filter with the cabin filter kept in place, a 6-log10 reduction was achieved after its removal and placement in the cabin during treatment.

CONCLUSIONS

Results from this study allow for informed decisions on the use of LCHP vapor as an effective decontamination approach for vehicle interiors.

Sensitive microscopic quantification of surface-bound prion infectivity for the assessment of surgical instrument decontamination procedures

BACKGROUND

Pathogenic prions (PrP^Sc) are amyloid-rich hydrophobic proteins which bind avidly to surgical surfaces and represent some of the most difficult targets during the reprocessing of reusable surgical instruments. In-vitro methods to amplify and detect the presence of otherwise undetectable prion contamination are available, but they do not measure associated infectivity. Most of these methods rely on the use of proteinase K, however this can lead to the loss of a substantial portion of PrP^Sc, potentially producing false negatives.

AIM

To develop a sensitive in-situ method without proteinase treatment for the dynamic quantification of amyloid accumulation in N2a #58 cells following 22L-prion infection from infected tissues and spiked stainless-steel surfaces.

METHODS

We spiked cultures of N2a #58 cells with the 22L prion strain in solution or dried on stainless-steel wires and directly measured the accumulation of prion amyloid aggregates over several passages using highly sensitive fluorescence microscopy.

FINDINGS

We demonstrated a 10-log dynamic range using our method to test residual prion infectivity, that was validated to show variable decontamination efficacy against prions from commercially available cleaning chemistries.

CONCLUSIONS

The new cell-based infectivity method presented here avoids partial or possibly total proteinase K digestion of PrP^Sc in samples for greater sensitivity, in addition to low cost, no ethical concerns, and adaptability to detect different prion strains. This method can be used to test cleaning chemistries' efficacy with greater sensitivity than measuring total residual proteins, which may not correlate with residual prion infectivity.

Filtration performance, fit test and side effects of respiratory personal protective equipment following decontamination: Observations for user safety and comfort

OBJECTIVE

While facing personal protective equipment (PPE) shortages during the COVID-19 pandemic, several institutions looked to PPE decontamination and reuse options. This study documents the effect of two hydrogen peroxide treatments on filtration efficiency and fit tests as well as the side effects for volunteers after the decontamination of N95 filtering facepiece respirators (FFRs). We also propose an efficient and large-scale treatment protocol that allows for the traceability of this protective equipment in hospitals during PPE shortages.

METHODS

The effects of low-temperature hydrogen peroxide sterilization and hydrogen peroxide vapor (HPV) on two FFR models (filtration, decontamination level, residual emanation) were evaluated. Ten volunteers reported comfort issues and side effects after wearing 1h FFRs worn and decontaminated up to five times.

RESULTS

The decontamination process does not negatively affect FFR efficiency, but repeated use and handling tend to lead to damage, limiting the number of times FFRs can be reused. Moreover, the recommended 24-h post-treatment aeration does not sufficiently eliminate residual hydrogen peroxide. Prolonged aeration time increased user comfort when using decontaminated FFRs.

CONCLUSIONS

HPV and low-temperature hydrogen peroxide sterilization seem to be appropriate treatments for FFR decontamination when the PPE is reused by the same user. PPE decontamination and reuse methods should be carefully considered as they are critical for the comfort and safety of healthcare workers.

Sustainable decontamination of heavy metal in wastewater and soil with novel rectangular wave asymmetrical alternative current electrochemistry

A new concept of removal and recovery of heavy metals and simultaneous regeneration and reuse of ethylenediamine-tetraacetic acid (EDTA) in soil washing effluent containing metal-EDTA complexes is proposed, which is used to remediate heavy metal contaminated soil. To achieve this goal, soil washing approach coupled with rectangular wave asymmetrical alternative current electrochemistry (RW-ACE) equipped with amidoxime-functionalized electrodes (Ami-CF) is employed. With high hydrophilicity and strong binding affinity, Ami-CF could specifically compete for heavy metals over EDTA under electric field. RW-ACE system is found successfully to achieve the non-destructive decomplexation of heavy metal-EDTA, and then regenerate EDTA for highly recycling, which saves as high as 98.9 % EDTA consumption compared with conventional washing method. Moreover, more than 90% of heavy metals are recovered and deposited on the electrode with a majority of them existed as zero-valence state as evidenced by XPS. The RW-ACE method is universal for various heavy metals such as Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ in an authentic contaminated soil, and the loss of soil nutrient is very limited. Along with long-term assessment and operation cost estimation, the RW-ACE method is a sustainable remediation approach for the heavy metal polluted wastewater and soils, and easily scaled up for field practice.

Decontamination of mustard sulfur and VX by sodium percarbonate complexed with 1-acetylguanidine as a novel activator

The peroxide-based decontaminants had attracted great attention for degradation of chemical warfare agents (CWAs) because of their high performance, non-corrosive and environmental-friendly merits. Hydrogen peroxide can be activated by some organic activators to enhance the oxidation ability. In this work, a novel formula based on sodium percarbonate (SPC) complexed with 1-acetylguanidine (ACG) was investigated for decontamination of sulfur mustard (HD) and VX as CWAs. In the experimental results, the active species acetyl peroxide imide acid in the formula aqueous solution was detected in situ by Raman and ¹³C NMR spectroscopy. The optimized conditions of the decontamination formula (SPC/ACG) were suggested that, the molar ratio of active oxygen and activator ([O]/[ACG]) was 1:1 while the pH value of the formula aqueous solution was about 9. To achieve the decontamination percentage over 99%, the molar ratio of active oxygen to CWA ((O)/(CWA)) needed to be at least 3 for HD and 7 for VX. Meanwhile, the degradation products detected by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and ion chromatography (IC) indicated that the oxidation and elimination reactions should have occurred on HD molecule, while the degradation of VX mainly originate from the nucleophilic substitution and oxidation reactions.