Environmental Disinfection Strategies to Prevent Indirect Transmission of SARS-CoV2 in Healthcare Settings

Bioinspired Assembly of Natural Polyphenol-Amino Acid Surfactants as Multifunctional Durable Coatings for Anticorrosion Fruit Packaging

Challenges emerge in the quest for highly efficient and biocompatible coatings to tackle microbial contamination. Here, we propose a bioinspired paradigm combining (-)-epigallocatechin gallate (EGCG) and l-arginine surfactants (LAM) as all-green building blocks for advanced coatings with superior performance. Molecular dynamics simulations reveal the natural assembly process of the EGCG/LAM supramolecular nanoparticles (ELA NPs). Notably, the coatings retain 99.0% antimicrobial activity even after eight cycles of use and exhibit highly adhesive and anti-water washing properties, maintaining their efficacy after eight uses and 30 days of water soaking on various substrates. When applied as sustainable food packaging coatings for perishable fruits at room temperature, the ELA coatings significantly extend the shelf life of strawberries and cherry tomatoes, reducing weight loss and maintaining firmness and sweetness. This study demonstrates the potential of ELA NPs as versatile and durable coating materials for mitigating food waste and agricultural economic losses due to microbial pollution.

Efficacy of Antimicrobial Dry Fog in Improving the Environmental Microbial Burden in an Inpatient Ward

Background/Objectives: In healthcare environments with high microbial loads, effective infection control measures are critical for reducing airborne and surface contamination. One of the novel modalities in the achievement of these goals is the use of antimicrobial mists, such as droplets, in the form of dry fog. Although the usage of dry fog in the disinfection of contained healthcare microenvironments is well known, the effect of such a system in terms of a meaningful reduction in the microbial burden in an open inpatient ward is unclear. Our objective was to assess the impact of scheduled dry fogging on microbial reduction in such settings. Methods: We collected air and surface samples from rooms receiving daily, biweekly, or no fogging (controls) over six months, establishing the baseline contamination and evaluating the reduction trends in treated rooms. The "reduction effect" was measured by tracking microbial isolation trends before and after treatment, while the "degree of reduction" assessed differences across rooms with varied disinfection schedules. Results: The results indicate that scheduled dry fogging significantly reduced microbial loads in treated rooms, especially with daily disinfection (SE = 64.484, p = 0.002). The airborne contamination in treated rooms showed a strong downward trend over time (SE = 19.192, p < 0.001). Surface contamination remained challenging due to frequent recontamination; however, treated rooms exhibited a consistent reduction in microbial presence (SE = 2.002, p = 0.010), confirming dry fogging's role as a valuable adjunct to routine cleaning. Conclusions: In conclusion, this study highlights that dry fogging effectively reduces microbial loads in open, high-traffic healthcare environments, supporting its use as part of a multimodal infection control strategy.

Kinetics of inactivation of bacteria responsible for infections in hospitals using UV-LED

Controlling the microbial load in the environment is crucial to prevent the spread of organisms. The continuous spread of nosocomial infections in hospital facilities and the emergence of the coronavirus (COVID-19) highlighted the importance of disinfection processes in health safety. This work aimed to evaluate the effectiveness of LED-based disinfection lamps on bacteria from the ESKAPEE group and virus phage in vitro inactivation to be applied in hospital environments and health facilities disinfection. This study evaluated the effect of different UV wavelengths (275 nm, 280 nm (UVC), 310 nm (UVB) and 340 nm (UVA)) on the disinfection process of various microbial indicators including E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499. Exposure time (5 min-30 min), exposure distance (0.25 m and 0.5 m) and surface materials (glass, steel, and polished wood) were evaluated on the disinfection efficiency. Furthermore, the study determined the recovery capacity of each species after UV damage. UVC-LED lamps could inactivate 99.99 % of microbial indicators after 20 min exposures at a 0.5 m distance. The exposure time needed to completely inactivate E. coli, S. aureus, P. aeruginosa, B. subtilis and Bacteriophage lambda DSM 4499 can be decreased by reducing the exposure distance. UVB-LED and UVA-LED lamps were not able to promote a log reduction of 4 and were not effective on B. subtilis or bacteriophage lambda DSM 4499 inactivation. Thus, only UVC-LED lamps were tested on the decontamination of different surface materials, which was successful. P. aeruginosa showed the ability to recover from UV damage, but its inactivation rate remains 99.99 %, and spores from B. subtilis were not completely inactivated. Nevertheless, the inactivation rate of these indicators remained at 99.99 % with 24 h incubation after UVC irradiation. UVC-LED lamps emitting 280 nm were the most indicated to disinfect surfaces from microorganisms usually found in hospital environments.

A critical mini-review on challenge of gaseous O3 toward removal of viral bioaerosols from indoor air based on collision theory

COVID-19, a pandemic of acute respiratory syndrome diseases, led to significant social, economic, psychological, and public health impacts. It was not only uncontrolled but caused serious problems at the outbreak time. Physical contact and airborne transmission are the main routes of transmission for bioaerosols such as SARS-CoV-2. According to the Centers for Disease Control (CDC) and World Health Organization (WHO), surfaces should be disinfected with chlorine dioxide, sodium hypochlorite, and quaternary compounds, while wearing masks, maintaining social distance, and ventilating are strongly recommended to protect against viral aerosols. Ozone generators have gained much attention for purifying public places and workplaces' atmosphere, from airborne bioaerosols, with specific reference to the COVID-19 pandemic outbreak. Despite the scientific concern, some bioaerosols, such as SARS-CoV-2, are not inactivated by ozone under its standard tolerable concentrations for human. Previous reports did not consider the ratio of surface area to volume, relative humidity, temperature, product of time in concentration, and half-life time simultaneously. Furthermore, the use of high doses of exposure can seriously threaten human health and safety since ozone is shown to have a high half-life at ambient conditions (several hours at 55% of relative humidity). Herein, making use of the reports on ozone physicochemical behavior in multiphase environments alongside the collision theory principles, we demonstrate that ozone is ineffective against a typical bioaerosol, SARS-CoV-2, at nonharmful concentrations for human beings in air. Ozone half-life and its durability in indoor air, as major concerns, are also highlighted in particular.

Hierarchical Superstructure of Plant Polyphenol and Arginine Surfactant for Long-Lasting and Target-Selective Antimicrobial Application

Antimicrobial agents are massively used to disinfect the pathogen contaminated surfaces since the Corona Virus Disease 2019 (COVID-19) outbreak. However, their defects of poor durability, strong irritation, and high environmental accumulation are exposed. Herein, a convenient strategy is developed to fabricate long-lasting and target-selective antimicrobial agent with the special hierarchical structure through bottom-up assembly of natural gallic acid with arginine surfactant. The assembly starts from rodlike micelles, further stacking into hexagonal columns and finally interpenetrating into spherical assemblies, which avoid explosive release of antimicrobial units. The assemblies show anti-water washing and high adhesion on various surfaces; and thus, possess highly efficient and broad-spectrum antimicrobial activities even after using up to eleven cycles. Both in vitro and in vivo experiments prove that the assemblies are highly selective in killing pathogens without generating toxicity. The excellent antimicrobial virtues well satisfy the increasing anti-infection demands and the hierarchical assembly exhibits great potential as a clinical candidate.

Environmental impacts of the widespread use of chlorine-based disinfectants during the COVID-19 pandemic

Chlorinated disinfectants are widely used in hospitals, COVID-19 quarantine facilities, households, institutes, and public areas to combat the spread of the novel coronavirus as they are effective against viruses on various surfaces. Medical facilities have enhanced their routine disinfection of indoors, premises, and in-house sewage. Besides questioning the efficiency of these compounds in combating coronavirus, the impacts of these excessive disinfection efforts have not been discussed anywhere. The impacts of chlorine-based disinfectants on both environment and human health are reviewed in this paper. Chlorine in molecular and in compound forms is known to pose many health hazards. Hypochlorite addition to soil can increase chlorine/chloride concentration, which can be fatal to plant species if exposed. When chlorine compounds reach the sewer/drainage system and are exposed to aqueous media such as wastewater, many disinfection by-products (DBPs) can be formed depending on the concentrations of natural organic matter, inorganics, and anthropogenic pollutants present. Chlorination of hospital wastewater can also produce toxic drug-derived disinfection by-products. Many DBPs are carcinogenic to humans, and some of them are cytotoxic, genotoxic, and mutagenic. DBPs can be harmful to the flora and fauna of the receiving water body and may have adverse effects on microorganisms and plankton present in these ecosystems.

Burden of Hospital-acquired SARS-CoV-2 Infections in Germany

Background

Avoiding in-hospital transmissions has been crucial in the COVID-19 pandemic. Little is known on the extent to which hospital-acquired SARS-CoV-2 variants have caused infections in Germany.

Aim

To analyse the occurrence and the outcomes of HAI with regard to different SARS-CoV-2 variants.

Methods

Patients with SARS-CoV-2 infections hospitalized between March 1^st, 2020 and May 17^th, 2022 in 79 hospitals of the Helios Group were included. Information on patients' characteristics and outcomes were retrieved from claims data. In accordance with the Robert Koch Institute, infections were classified as hospital-acquired when tested positive >6 days after admission and if no information hinted at a different source.

Findings

In all, 62,875 SARS-CoV-2 patients were analysed, of whom 10.6% had HAI. HAIs represented 14.7% of SARS-CoV-2 inpatients during the Wildtype period, 3.5% during Alpha (odds ratio: 0.21; 95% confidence interval: 0.19–0.24), 8.8% during Delta (2.70; 2.35–3.09) and 10.1% during Omicron (1.10; 1.03–1.19). When age and comorbidities were accounted for, HAI had lower odds for death than community-acquired infections (0.802; 0.740–0.866). Compared to the Wildtype period, HAIs during Omicron were associated with lower odds for ICU (0.78; 0.69–0.88), ventilation (0.47; 0.39–0.56), and death (0.33; 0.28–0.40).

Conclusion

Hospital-acquired SARS-CoV-2 infections occurred throughout the pandemic, affecting highly vulnerable patients. Although transmissibility increased with newer variants, the proportion of HAIs decreased, indicating improved infection prevention and/or the effect of immunization. Furthermore, the Omicron period was associated with improved outcomes. However, the burden of hospital-acquired SARS-CoV-2 infections remains high.

Electrostatic Spray Disinfection Using Nano-Engineered Solution on Frequently Touched Surfaces in Indoor and Outdoor Environments

The COVID-19 pandemic has resulted in high demand for disinfection technologies. However, the corresponding spray technologies are still not completely optimized for disinfection purposes. There are important problems, like the irregular coverage and dripping of disinfectant solutions on hard and vertical surfaces. In this study, we highlight two major points. Firstly, we discuss the effectiveness of the electrostatic spray deposition (ESD) of nanoparticle-based disinfectant solutions for systematic and long-lasting disinfection. Secondly, we show that, based on the type of material of the substrate, the effectiveness of ESD varies. Accordingly, 12 frequently touched surface materials were sprayed using a range of electrostatic spray system parameters, including ion generator voltage, nozzle spray size and distance of spray. It was observed that for most cases, the surfaces become completely covered with the nanoparticles within 10 s. Acrylic, Teflon, PVC, and polypropylene surfaces show a distinct effect of ESD and non-ESD sprays. The nanoparticles form a uniform layer with better surface coverage in case of electrostatic deposition. Quantitative variations and correlations show that 1.5 feet of working distance, an 80 μm spray nozzle diameter and an ion generator voltage of 3-7 kV ensures a DEF (differential electric field) that corresponds to an optimized charge-to-mass ratio, ensuring efficient coverage of nanoparticles.

Aging assessment of microplastics (LDPE, PET and uPVC) under urban environment stressors

The changes in the chemical structure, surface morphology and crystallinity are reported for three different polymers (LDPE, PET and uPVC) in microplastic form, after being artificially exposed to different aging agents that can affect microplastics in urban environments: ozone, UV-C, and solar radiation. In parallel to the laboratory experiments, the microplastics were exposed to real weathering conditions for three-months in a building rooftop located in the city of Porto (Portugal). By analysing the (virgin and aged) microplastic samples periodically through ATR-FTIR spectroscopy and estimating the Carbonyl Index, it was possible to sketch the aging degree evolution through time and identify the most aggressive agents for each polymer regarding the changes in their chemical structure. SEM and XRD measurements allowed to complement the ATR-FTIR results, giving a more complete picture of the effects of each treatment on each polymer and suggesting that ATR-FTIR measurements are not sufficient to correctly evaluate the aging degree of microplastics. The changes observed in the microplastic particles studied support the theory that microplastics in the environment undergo aging and change their characteristics through time, potentially affecting their behavior and intensifying their impacts.

Efficacy of frontline chemical biocides and disinfection approaches for inactivating SARS-CoV-2 variants of concern that cause coronavirus disease with the emergence of opportunities for green eco-solutions

The emergence of severe acute respiratory disease (SARS-CoV-2) variants that cause coronavirus disease is of global concern. Severe acute respiratory disease variants of concern (VOC) exhibiting greater transmissibility, and potentially increased risk of hospitalization, severity and mortality, are attributed to molecular mutations in outer viral surface spike proteins. Thus, there is a reliance on using appropriate counter-disease measures, including non-pharmaceutical interventions and vaccination. The best evidence suggests that the use of frontline biocides effectively inactivate coronavirus similarly, including VOC, such as 202012/01, 501Y.V2 and P.1 that have rapidly replaced the wild-type variant in the United Kingdom, South Africa and Brazil, respectively. However, this review highlights that efficacy of VOC-disinfection will depend on the type of biocide and the parameters governing the activity. VOC are likely to be similar in size to the wild-type strain, thus implying that existing guidelines for use and re-use of face masks post disinfection remain relevant. Monitoring to avoid injudicious use of biocides during the coronavirus disease era is required as prolonged and excessive biocide usage may negatively impact our receiving environments; thus, highlighting the potential for alternative more environmental-friendly sustainable biocide solutions. Traditional biocides may promote cross-antimicrobial resistance to antibiotics in problematical bacteria. The existing filtration efficacy of face masks is likely to perform similarly for VOC due to similar viral size; however, advances in face mask manufacturing by way incorporating new anti-viral materials will potentially enhance their design and functionality for existing and potential future pandemics.

Potential Mucosal Irritation Discrimination of Surface Disinfectants Employed against SARS-CoV-2 by Limacus flavus Slug Mucosal Irritation Assay

Preventive measures have proven to be the most effective strategy to counteract the spread of the SARS-CoV-2 virus. Among these, disinfection is strongly suggested by international health organizations' official guidelines. As a consequence, the increase of disinfectants handling is going to expose people to the risk of eyes, mouth, nose, and mucous membranes accidental irritation. To assess mucosal irritation, previous studies employed the snail Arion lusitanicus as the mucosal model in Slug Mucosal Irritation (SMI) assay. The obtained results confirmed snails as a suitable experimental model for their anatomical characteristics superimposable to the human mucosae and the different easily observed readouts. Another terrestrial gastropod, Limacus flavus, also known as " Yellow slug ", due to its larger size and greater longevity, has already been proposed as an SMI assay alternative model. In this study, for the first time, in addition to the standard parameters recorded in the SMI test, the production of yellow pigment in response to irritants, unique to the snail L. flavus, was evaluated. Our results showed that this species would be a promising model for mucosal irritation studies. The study conducted testing among all those chemical solutions most commonly recommended against the SARS-CoV-2 virus.

Technological Advances in Ozone and Ozonized Water Spray Disinfection Devices

To control infectious diseases such as the severe acute respiratory syndrome coronavirus (Covid-19) that caused the current pandemic, disinfection measures are essential. Among building measures, disinfection chambers can help to decrease the transmission rate through the sanitizing capacity of the disinfectant used, which can thereby clean surfaces or humans. Out of existing biocides, ozone is considered one of the safest for humans, but one of the most powerful oxidizers, making the substance a better alternative as the biocidal solution in disinfection chambers. Analyses were carried out by using all patented documents related to disinfection chambers that used ozone as a disinfectant. A Derwent Innovation Index (DII) database search was undertaken to find these patents. Patent prospecting resulted in 620 patent documents that were divided into 134 patent families. There was no technology related to protective barriers for individuals, and the majority of patents in the retrieved data aimed at sterilizing medical devices and surfaces. Given that the specific Cooperative Patent Classification (CPC) code for ozone dissolved in liquid was used in the methodology search, but not included among the 10 most used codes in the patents, the use of ozonized water may be an innovative approach in the technology landscape of sterilization chambers.