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Abstract Background Aerosols generated during toilet flushing are a potential source for transmission of viral and bacterial pathogens in bathrooms. However, manual decontamination of bathrooms after each use is not feasible. Methods We tested the efficacy of a wall-mounted far ultraviolet-C (UV-C) light technology that only delivers far UV-C when people are not present for decontamination of surfaces and aerosolized viral particles in an unoccupied hospital bathroom. A quantitative disk carrier test method was used to test efficacy against organisms on steel disk carriers placed in 9 sites in the bathroom with an exposure time of 45 min and 2 h; Clostridioides difficile spores were also exposed for 24 h. Efficacy against aerosolized bacteriophage MS2 was tested with a 45-minute exposure. Results The far UV-C technology reduced methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Candida auris, and bacteriophage MS2 on steel disk carriers by ≥ 1.2 log10 (range, 1.2 to 4.2 log10) at all test sites after 2 h of exposure. The technology reduced C. difficile spores by

Background: Aerosols generated during toilet flushing are a potential source for transmission of viral and bacterial pathogens in bathrooms. However, manual decontamination of bathrooms after each use is not feasible. Methods: We tested the efficacy of a wall-mounted far ultraviolet-C (UV-C) light technology that only delivers far UV-C when people are not present for decontamination of surfaces and aerosolized viral particles in an unoccupied hospital bathroom. A quantitative disk carrier test method was used to test efficacy against organisms on steel disk carriers placed in 9 sites in the bathroom with an exposure time of 45 min and 2 h; Clostridioides difficile spores were also exposed for 24 h. Efficacy against aerosolized bacteriophage MS2 was tested with a 45-minute exposure. Results: The far UV-C technology reduced methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Candida auris, and bacteriophage MS2 on steel disk carriers by ≥ 1.2 log10 (range, 1.2 to 4.2 log10) at all test sites after 2 h of exposure. The technology reduced C. difficile spores by < 1 log10 after 2 h exposure, but 4 of 9 test locations had ≥ 2 log10 reductions after 24 h exposure. Aerosolized bacteriophage MS2 was reduced by 4 log10 plaque-forming units in 45 min. Conclusions: The far UV-C light technology could potentially be useful for automated decontamination of air and surfaces in bathrooms in healthcare and community settings. [ABSTRACT FROM AUTHOR]

Summary: In response to the growing concern of transmitting pathogenic viruses through food, this research aimed to assess the impact of various factors on the commercial packaging of meat (chicken and beef) on the inactivation of bacteriophage MS2 which was scrutinised by examining the influence of packaging type, bacteriophage spiking levels, temperature, as well as the meat shape and type. The findings revealed that the recovery of bacteriophage MS2 from minced beef was lower in modified atmosphere packaging (MAP) compared with air packaging (AP) at both storage times, spiking levels, and freezing and refrigerating temperatures. On the other hand, the recovery of the bacteriophage from chopped beef was lower in AP than in MAP in refrigerating conditions at both spiking levels during the 3 days of storage. According to our findings, the recovery levels of bacteriophage MS2 from chicken had statistically significant differences in both packaging types at different spiking levels. Storage conditions and packaging type were the most essential parameters in bacteriophage MS2 viability. The lowest bacteriophage viability belonged to MAP. [ABSTRACT FROM AUTHOR]

Viral infections are directional; the mechanisms of assembly and disassembly are distinct and coordinated. Molecular frustration describes the coexistence of alternative states of a macromolecular system where all favourable interactions cannot be satisfied simultaneously. We hypothesize that molecular frustration of the coat proteins and their complexes with the genome in bacteriophage MS2 accounts for regulation of assembly and disassembly during infection. We therefore hypothesize that the same phenomenon may also underlie the directionality of other viral infections, for example, how cellular cofactors regulate infection by HIV. The recent revolution in imaging techniques and results from RNA footprinting in situ reveal how the bacteriophage MS2 genome regulates both particle assembly and genome release. We have proposed a model in which multiple packaging signal (PS) RNA-coat protein (CP) contacts orchestrate different stages of a viral life cycle. Programmed formation and release of specific PS contacts with CP regulates viral particle assembly and genome uncoating during cell entry. We hypothesize that molecular frustration, a concept introduced to understand protein folding, can be used to better rationalize how PSs function in both particle assembly and genome release. More broadly this concept may explain the directionality of viral life cycles, for example, the roles of host cofactors in HIV infection. We propose that this is a universal principle in virology that explains mechanisms of host–virus interaction and suggests diverse therapeutic interventions. [ABSTRACT FROM AUTHOR]

Successful assembly of bacteriophage MS2 virus-like particles (VLPs) from a secreted recombinant capsid protein in the culture medium of the Komagataella phaffii methylotrophic yeast has been shown. The yield of VLPs was 5 g/L and reached 30% of the total protein of the culture liquid supernatant. The VLPs were well-ordered icosahedral structures with a diameter of 26‒28 nm, which was confirmed by transmission electron microscopy. A simple method for the isolation and purification of the VLPs was proposed, which ensures the purity of the target protein structures of more than 90%. The results we obtained can be used for development of a technology for the large-scale production of recombinant vaccines based on bacteriophage MS2 VLPs. [ABSTRACT FROM AUTHOR]

The global COVID-19 pandemic has warned scientists of the requirement to look for new antimicrobial compounds to prevent infection by this type of viral pathogen. Natural compounds are becoming a promising avenue of research thanks to their renewable, biodegradable, and non-toxic properties. In this work, tiger nut milk's (TNM) antiviral properties, with and without sugar, were studied against enveloped and non-enveloped viruses. The antiviral properties of TNM were evaluated at different concentrations. The antiviral tests showed that TNM is antiviral against the enveloped bacteriophage phi 6, which is commonly used as a surrogate for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), although it did not have any antiviral effect against the non-enveloped bacteriophage MS2. We also found that adding sugar to this natural drink can improve its antiviral properties against enveloped viruses and render it antiviral against non-enveloped viruses like bacteriophage MS2. The antiviral activity of TNM depends on the TNM concentration. TNM is a natural bioproduct that could help to fight against viral infections and protect against a wide range of viral illnesses. These results confirm that the typical sweetened drink made from tiger nut extract and sugar (known as horchata in Spain) possesses broad-spectrum antiviral properties. [ABSTRACT FROM AUTHOR]

Pathogenic microorganisms pose a severe risk to the aquatic environment and human health. Membrane bioreactors (MBRs) have attracted much attention due to their simultaneous biological treatment and virus retention, but membrane fouling is the main obstacle. This study explored the effect of micro-granular activated carbon (μGAC) on bacteriophage MS2 removal efficiency and membrane fouling in a flat-plate MBR. The results showed that the μGAC addition with a particle size of 180–300 μm improved the removal of MS2 (LRV MBR of 4.77 log) and enhanced the removal of COD and ammonia nitrogen. The μGAC integrated MBR (μGAC-MBR) exhibited a higher MS2 retention rate by the membrane filter layers with an average LVR Mem of 2.03 log compared to that of a control reactor (C-MBR) of 1.89 log. Meanwhile, the total membrane filter layer resistance of μGAC-MBR was significantly lower than that of C-MBR, particularly in terms of cake layer resistance and organic pore-blocking exclusion. The μGAC addition slightly reduced MS2 adsorption by the activated sludge while significantly altering the extracellular polymeric substances (EPS) profiles. The fluorescent components in the bound EPS and PN/PS ratio of the activated sludge were reduced. We found that μGAC enhanced membrane surface roughness and hydrophilicity. Notably, the μGAC significantly influenced the quorum sensing (QS) systems, reducing the abundance and synthesis of AHL-related genes. The synthase luxI in the AHL-QS system was reduced by 93.21% in μGAC-MBR. The AHL-QS system is closely related to biofilm formation, and the total EPS of the surface filer layer of μGAC-MBR decreased by 57.73%, and PN in LB-EPS and TB-EPS decreased by 91.33% and 54.44% compared with C-MBR, indicating a significant reduction in biofilm formation. This study exhibited a new perspective on promoting MS2 removal with the synergistic effect of alleviating fouling in the MBR process. • The integration of μGAC into MBR reached an average MS2 removal rate of 4.77 log. • The μGAC addition changed the morphology and hydrophilicity of the filter layer. • The luxI in the AHL-QS system has reduced by 93.21% in the cake layer of μGAC-MBR. • The μGAC addition has led to an inhibition of EPS and mitigation of fouling of MBR. • The μGAC reduces membrane fouling via scouring and impacts the microbial community. [ABSTRACT FROM AUTHOR]

Background Hospitalized patients are at risk to acquire severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from roommates with unrecognized coronavirus disease 2019 (COVID-19). We hypothesized that airflow patterns might contribute to SARS-CoV-2 transmission in double-occupancy patient rooms. Methods A device emitting condensed moisture was used to identify airflow patterns in double-occupancy patient rooms. Simulations were conducted to assess transfer of fluorescent microspheres, 5% sodium chloride aerosol, and aerosolized bacteriophage MS2 between patient beds 3 meters apart and to assess the effectiveness of privacy curtains and portable air cleaners in reducing transfer. Results Air flowed from inlet vents in the center of the room to an outlet vent near the door, resulting in air currents flowing toward the bed adjacent to the outlet vent. Fluorescent microspheres (212–250-µm diameter), 5% sodium chloride aerosol, and aerosolized bacteriophage MS2 released from the inner bed were carried on air currents toward the bed adjacent to the outlet vent. Closing curtains between the patient beds reduced transfer of each of the particles. Operation of a portable air cleaner reduced aerosol transfer to the bed adjacent to the outlet vent but did not offer a benefit over closing the curtains alone, and in some situations, resulted in an increase in aerosol exposure. Conclusions Airflow patterns in double-occupancy patient rooms may contribute to risk for transmission of SARS-CoV-2 between roommates. Keeping curtains closed between beds may be beneficial in reducing risk. [ABSTRACT FROM AUTHOR]

In South Korea, testing disinfectants against foot-and-mouth disease virus (FMDV) that are contagious in livestock or that require special attention with respect to public hygiene can be manipulated only in high-level containment laboratories, which are not easily available. This causes difficulties in the approval procedure for disinfectants, such as a prolonged testing period. Additionally, the required biosafety level (BSL) in the case of FMDV has hindered its extensive studies. However, this drawback can be circumvented by using a surrogate virus to improve the performance of the efficacy testing procedure for disinfectants. Therefore, we studied bacteriophage MS2 (MS2) and bovine enterovirus type 1 (ECBO) with respect to disinfectant susceptibility for selecting a surrogate for FMDV according to the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. Effective concentrations of the active substances in disinfectants (potassium peroxymonosulfate, sodium dichloroisocyanurate, malic acid, citric acid, glutaraldehyde, and benzalkonium chloride) against FMDV, MS2, and ECBO were compared and, efficacies of eight APQA-listed commercial disinfectants used against FMDV were examined. The infectivity of FMDV and ECBO were confirmed by examination of cytopathic effects, and MS2 by plaque assay. The results reveal that the disinfectants are effective against MS2 and ECBO at higher concentrations than in FMDV, confirming their applicability as potential surrogates for FMDV in efficacy testing of veterinary disinfectants. [ABSTRACT FROM AUTHOR]

Waterborne pathogens are a leading cause of disease and death worldwide. Ultraviolet (UV) irradiation is an effective method of drinking water treatment through the destruction of cells at the molecular level. Throughput capacity per unit volume of the UV unit is a major driver of the treatment process. In this study, we developed a microscale-based reactor in combination with UV radiation to determine the inactivation efficacy of bacteriophage MS2 and Escherichia coli. Using the microscale-based reactor, we achieved inactivation of more than 7 log colony forming units per mL of E. coli by 8 s and removal of more than 7.5 log plaque forming units per mL of bacteriophage MS2 by 8 min residence times. These values meet and surpass the standards set by the U.S.-Environmental Protection Agency and the World Health Organization for drinking water treatment technologies. Results from mathematical modeling suggest that the best fit model is obtained when we assume that more than a single photon directly damages E. coli cells and allows a transitional damaged state or further inactivation by additional photons. The successful application of a point-of-use UV water disinfection device to inactivate pathogens creates new opportunities for household and commercial water treatment globally. [ABSTRACT FROM AUTHOR]

A variety of nanoscale scaffolds, including virus-like particles (VLPs), are being developed for biomedical applications; however, little information is available about their in vivo behavior. Targeted nanoparticles are particularly valuable as diagnostic and therapeutic carriers because they can increase the signal-to-background ratio of imaging agents, improve the efficacy of drugs, and reduce adverse effects by concentrating the therapeutic molecule in the region of interest. The genome-free capsid of bacteriophage MS2 has several features that make it well-suited for use in delivery applications, such as facile production and modification, the ability to display multiple copies of targeting ligands, and the capacity to deliver large payloads. Anti-EGFR antibodies were conjugated to MS2 capsids to construct nanoparticles targeted toward receptors overexpressed on breast cancer cells. The MS2 agents showed good stability in physiological conditions up to 2 days and specific binding to the targeted receptors in in vitro experiments. Capsids radiolabeled with 64Cu isotopes were injected into mice possessing tumor xenografts, and both positron emission tomography-computed tomography (PET/CT) and scintillation counting of the organs ex vivo were used to determine the localization of the agents. The capsids exhibit surprisingly long circulation times (10-15% ID/g in blood at 24 h) and moderate tumor uptake (2-5% ID/g). However, the targeting antibodies did not lead to increased uptake in vivo despite in vitro enhancements, suggesting that extravasation is a limiting factor for delivery to tumors by these particles.

Virus-like particles are used to encapsulate drugs, imaging agents, enzymes, and other biologically active molecules in order to enhance their function. However, the size of most virus-like particles is inflexible, precluding the design of appropriately sized containers for different applications. Here, we describe a chromatographic selection for virus-like particle assembly. Using this selection, we identified a single amino acid substitution to the coat protein of bacteriophage MS2 that mediates a uniform switch in particle geometry from T = 3 to T = 1 icosahedral symmetry. The resulting smaller particle retains the ability to be disassembled and reassembled in vitro and to be chemically modified to load cargo into its interior cavity. The pair of 27 and 17 nm MS2 particles will allow direct examination of the effect of size on function in established applications of virus-like particles, including drug delivery and imaging.

RNA bacteriophage MS2-derived virus-like particles (VLPs) have been widely used in biomedical research as model systems to study virus assembly, structure-function relationships, vaccine development, and drug delivery. Considering the diverse utility of these VLPs, a systemic engineering approach has been utilized to generate smaller particles with optimal serum stability and tissue penetrance. Additionally, it is crucial to demonstrate the overall stability of these mini MS2 VLPs, ensuring cargo protection until they reach their target cell/organ. However, no detailed analysis of the thermal stability and heat-induced disassembly of MS2 VLPs has yet been attempted. In this work, we investigated the thermal stability of both wild-type (WT) MS2 VLP and its "mini" variant containing S37P mutation (mini MS2 VLP). The mini MS2 VLP exhibits a higher capsid melting temperature ( T m ) when compared to its WT MS2 VLP counterpart, possibly attributed to its smaller interdimer angle. Our study presents that the thermal unfolding of MS2 VLPs follows a sequential process involving particle destabilization, nucleic acid exposure/melting, and disassembly of VLP. This observation underscores the disruption of cooperative intersubunit interactions and protein-nucleic acid interactions, shedding light on the mechanism of heat-induced VLP disassembly.

Bivalve molluscan shellfish such as oysters are important vectors for the transmission of foodborne pathogens including both viruses and bacteria. Photoinactivation provides a cold-sterilization option against the contamination as excited photosensitizers could transfer electronic energy to oxygen molecules producing reactive oxygen species such as singlet oxygen, leading to oxidative damage and death of the pathogens. However, the efficacy of photoinactivation is very often compromised by the presence of food matrix due to the nonselective reactions of short-lived singlet oxygen with organic matter other than the target pathogens. In order to address this issue, we encapsulated a food-grade photosensitizer rose bengal (RB) in alginate microbeads. An extra coating of chitosan effectively prevented the release of RB from the microbeads in seawater, and more importantly, enhanced the selectivity of the photoinactivation via the electrostatic interactions between cationic chitosan and anionic charge of the virus particles (bacteriophage MS2 and Tulane virus) and the Gram-negative bacteria Vibrio parahaemolyticus (V. parahaemolyticus). The treatment of oysters with microencapsulated RB resulted in significantly higher reductions of MS2 phage, Tulane virus and V. parahaemolyticus than free RB and non-RB carrying microbeads (P <0.05) tested with both in vitro and in vivo experimental set-ups. This study demonstrated a new strategy in delivering comprehensively formulated biochemical sanitizers in bivalve shellfish through their natural filter-feeding activity and thereby enhancing the mitigation efficiency of foodborne pathogen contamination. [ABSTRACT FROM AUTHOR]

In South Korea, testing disinfectants against foot-and-mouth disease virus (FMDV) that are contagious in livestock or that require special attention with respect to public hygiene can be manipulated only in high-level containment laboratories, which are not easily available. This causes difficulties in the approval procedure for disinfectants, such as a prolonged testing period. Additionally, the required biosafety level (BSL) in the case of FMDV has hindered its extensive studies. However, this drawback can be circumvented by using a surrogate virus to improve the performance of the efficacy testing procedure for disinfectants. Therefore, we studied bacteriophage MS2 (MS2) and bovine enterovirus type 1 (ECBO) with respect to disinfectant susceptibility for selecting a surrogate for FMDV according to the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. Effective concentrations of the active substances in disinfectants (potassium peroxymonosulfate, sodium dichloroisocyanurate, malic acid, citric acid, glutaraldehyde, and benzalkonium chloride) against FMDV, MS2, and ECBO were compared and, efficacies of eight APQA-listed commercial disinfectants used against FMDV were examined. The infectivity of FMDV and ECBO were confirmed by examination of cytopathic effects, and MS2 by plaque assay. The results reveal that the disinfectants are effective against MS2 and ECBO at higher concentrations than in FMDV, confirming their applicability as potential surrogates for FMDV in efficacy testing of veterinary disinfectants.

This study evaluated the effect of two biocontaminant surrogates on the activity and performance of activated sludge. In the presence of bacteriophage MS2 at 3.2 × 108 PFU/ml, the peak respiration rates varied between 9.1 and 10.5 mg O2/gVSS/hr, generally similar to the rates observed in negative controls. MS2 did not alter the molar CO2‐produced‐to‐O2 consumed stoichiometry observed during respiration. Similar results were observed for Bacillus globigii (BG). Ethanol, a potential co‐contaminant associated with biocontamination incidents, can inhibit initial oxygen uptake. MS2 and BG both adsorbed to activated sludge; post‐exposure viability was confirmed for BG but not for MS2. This study is the first to evaluate the effects of BG and MS2 on activated sludge, and it presents a protocol that can be used in operational situations. [ABSTRACT FROM AUTHOR]

The presence of airborne viruses in bioaerosols is a significant and ongoing public health concern. In this context, this study aimed to develop a new filter that integrates nanosilver into a TiO 2 -chitosan matrix (nano-Ag/TiO 2 -CS) to inactivate the non-enveloped bacteriophage MS2 as a viral aerosol surrogate. The materials were characterized using various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS). The SEM images showed that the nano-Ag particles were spheres with a high surface area for virus interactions and that the fiber surfaces were covered by nano-Ag, which enhanced contact with viruses. The optimal 5 wt% nano-Ag/TiO 2 -CS filter combined with a negative air ionizer (NAI) showed the highest viral aerosol removal efficiency, which reached 97 %. The use of an NAI during filtration enhanced the inactivation of the viral aerosols. A long-term antiviral efficacy assessment showed that the nano-Ag/TiO 2 -CS filter demonstrated robust durability, which is vital for real-world applications. The nanofilter proposed in this work is simple, safe, and cost-effective for inactivating viral aerosols to improve indoor air quality. • Simple and eco-friendly processed nano-Ag/TiO 2 -CS filters. • Synergetic effect of NAI on nano-filters for viral aerosol removal. • Remarkable antiviral activity was achieved by 5 wt% nano-Ag/TiO 2 -CS filters. • Inviability of the viral aerosol adsorbed on the nano-filter surface. [ABSTRACT FROM AUTHOR]

Background: Ultraviolet-C (UV-C) light devices are effective in reducing contamination on N95 filtering facepiece respirators. However, limited information is available on whether UV-C devices meet the Food and Drug Administration’s (FDA) microbiological requirements for Emergency Use Authorization (EUA) for respirator bioburden reduction. Methods: We tested the ability of 2 UV-C light boxes to achieve the 3-log10 microorganism reductions required for EUA for reuse by single users. Whole 3M 1860 or Moldex 1513 respirators were inoculated on the exterior facepiece, interior facepiece, and internal fibers with bacteriophage MS2 and/or 4 strains of bacteria and treated with UV-C cycles of 1 or 20 minutes. Colorimetric indicators were used to assess penetration of UV-C through the respirators. Results: For 1 UV-C box, a 20-minute treatment achieved the required bioburden reduction for Moldex 1513 but not 3M 1860 respirators. For the second UV-C box, a 1-minute treatment achieved the required bioburden reduction in 4 bacterial strains for the Moldex 1513 respirator. Colorimetric indicators demonstrated penetration of UV-C through all layers of the Moldex 1513 respirator but not the 3M 1860 respirator. Conclusions: Our findings demonstrate that UV-C box technologies can achieve bioburden reductions required by the FDA for EUA for single users but highlight the potential for variable efficacy for different types of respirators.

Anaerobic membrane bioreactors reduce the energy cost of wastewater treatment and meet filtration requirements for non-potable reuse. However, sulfides (H2S/HS−) formed during anaerobic treatment exert a high chlorine demand and inhibit UV disinfection by photon shielding at 254 nm. This study evaluated the feasibility of hydrogen peroxide (H2O2) for sulfide oxidation, UV disinfection for inactivation of MS2 bacteriophage, and chlorine to provide a residual for distribution. H2O2 treatment at pH ≥ 8 favored sulfide oxidation to sulfate in 30 min at a 4:1 H2O2:sulfide stoichiometry. Compared to a 6:1 H2O2:sulfide molar ratio, treatment of anaerobic effluent with 0.5 mM sulfides with a 4:1 H2O2:sulfide molar ratio would increase the applied UV fluence needed for 5-log MS2 inactivation from 180 mJ cm−2 to 225 mJ cm−2. However, the lower H2O2 dose reduced the dose of chlorine needed to quench residual H2O2 and provide a residual for distribution. Treatment at the 4:1 H2O2:sulfide molar ratio was favored, because the cost savings in H2O2 and chlorine reagents outweighed the energy savings associated with UV treatment. However, H2O2/UV/chlorine treatment of anaerobic effluent was cost-competitive with conventional treatment of aerobic effluent for non-potable reuse only for < 285 µM sulfides.

Aims: The efficacy of a novel photochemical method for generating chlorine dioxide (photoClO2) was evaluated against human noroviruses (HuNoV) surrogate, bacteriophage MS2, and Clostridium difficile endospores. Methods and Results: Chlorine dioxide was generated by mixing 1% sodium chlorite with 10 parts‐per‐million (ppm) Eosin Y and irradiating with a photo‐activator‐excitable light. PhotoClO2 efficacy was assessed against bacteriophage MS2 and C. difficile endospores in suspension, on hard surfaces and greenhouse conditions under soiled and unsoiled conditions. The estimated effective photoClO2 produced and consumed was 20·39 ± 0·16 ppm at a rate of 8·16 ppm per min in a 1% sodium chlorite solution. In suspension, MS2 phage was reduced by 3·35 and >5·10 log10 PFU per ml in 120 and 90 min, with and without soil, respectively. At the same time, when dried on stainless steel surface, MS2 phage was reduced by >4·53 log10 PFU per carrier in 30 min under both conditions. On the other hand, C. difficile endospores in suspension were reduced by 2·26 and 3·65 log10 CFU per ml in 120 min with and without soiling, respectively. However, on stainless steel surface, maximal reductions of the C. difficile endospores were 0·8 and 1·5 log10 CFU per carrier with and without soiling, respectively, and a maximal reduction of 2·97 log10 CFU per carrier under greenhouse conditions at 24 h. Conclusions: Overall, photoClO2 showed promise as a technology to control HuNoV contamination on environmental surfaces but requires further optimization and testing against C. difficile endospores. Significance and Impact of the Study: Results from this investigation will serve as a model for how to generate and quantify photoClO2 and how to appropriately evaluate this new class of disinfectants against environmentally resilient pathogens: viruses and bacterial endospores. [ABSTRACT FROM AUTHOR]

Waterborne pathogenic bacteria and viruses are of great concern to environmental and public health. This study focused on the impact of dissolved organic matter (DOM) on photocatalytic inactivation of bacteriophage MS2 by utilizing a visible-light-responded photocatalyst composed of rGO-supported g-C 3 N 4 (7.5%GCN). The results showed that the inactivation rate of MS2 by 7.5%GCN photocatalysis was 3.20 log at λ > 400 nm and 3.27 log at λ > 305 nm within 120 min. The presence of humic acid (HA) in the water matrix led to a decline in the inactivation rate of 2.19 log at λ > 400 nm and 2.08 log at λ > 305 nm, representing a reduction of 31.56% and 36.4%. During an 8 h inactivation process in ultrapure water using 7.5%GCN photocatalysis under λ > 400 nm, steady-state concentrations of 1O 2 , •OH, •O 2 - and H 2 O 2 were measured to be 5.67 × 10-13, 8.56 × 10-7, 1.21 × 10-5 and 7.08 × 10-5 mol/L, respectively; When in presence of HA, the concentrations of ROSs were inhibited except for 1O 2. The order of ROS steady-state concentration was found to be H 2 O 2 > •O 2 -> •OH> 1O 2 during 7.5%GCN photocatalysis, both within and without HA. Transmission electron microscopy (TEM) analysis revealed that the distortion in the morphology of MS2, potentially leading to the disclosure of RNA. Furthermore, protein analysis indicated that the protein structure was damaged, resulting in a decrease of approximately 90% in its concentration. This study may shed light on the impact of DOM during solar light-driven photocatalysis, offering a green, environment-friendly, and sustainable water treatment process. [Display omitted] • The HA can inactivate MS2 in water under light irradiation by generating 3DOM*. • The HA inhibits the 7.5%GCN inactivation rate of MS2 due to its quenching effect. • The H 2 O 2 and •O 2 - mainly contribute to MS2 inactivation in 7.5%GCN with HA system. • The ROSs distorted the morphology of MS2 and damaged the protein structure. [ABSTRACT FROM AUTHOR]

Aims: (i) To develop an analytical method for recovery and quantification of bacteriophage MS2—as a surrogate for foot‐and‐mouth disease virus—from complex porous surfaces, with and without the presence of laboratory‐developed agricultural grime; (ii) to evaluate, with a 4‐log dynamic range, the virucidal activity of common biocides for their ability to decontaminate surfaces and hence remediate facilities, following a foreign animal disease contamination incident. Methods and Results: An analytical method was developed and optimized for MS2 recovery from simulated agricultural surfaces. The addition of Dey–Engley neutralizing broth to an extraction buffer improved MS2 viability in liquid extracts, with optimal analytical holding times determined as <8 to ≤24 h, depending on matrix. The recovery of MS2 from surface materials decreased in the order: nonporous reference material >grimed porous materials >nongrimed porous materials. In disinfectant testing, two spray applications of pAB were effective against MS2 (≥4‐log reduction) on all operational‐scale materials. Two per cent citric acid had limited effectiveness, with a ≥4‐log reduction observed on a selected subset of grimed concrete samples. Conclusions: Decontamination efficacy test results can be affected by surface characteristics, extraction buffer composition, analytical holding time and surface‐specific organism survivability. Efficacy should be evaluated using a test method that reflects the environmental characteristics of the intended application. Significance and Impact of the Study: The results of this study demonstrate the importance of analytical method verification tests for disinfectant testing prior to application in complex environments. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Hypotheses By selecting constituent polyelectrolytes and controlling conditions of their deposition, the resulting polyelectrolyte multilayers can be designed as surface coatings with controlled adhesive properties with respect to viruses. Charge and hydrophilicity of the polyelectrolyte multilayers govern virus adhesion. Experiments Four surfaces of different charges and hydrophobicities were designed using a layer-by-layer assembly of poly(styrene-4-sulfonate) and poly(dimethyl diallyl ammonium chloride). Contact angle measurements gave an estimate of MS2 hydrophilicity in terms of free energy of interfacial interaction in water. Experimental results on MS2 adhesion obtained using quartz crystal microbalance with dissipation monitoring were compared with predictions by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Findings MS2 deposition onto polyelectrolyte multilayers occurred in two phases: an early phase defined by virus-surface interactions and a later phase with virus-virus interactions controlling deposition kinetics. Principal component analysis showed that the deposition rates in the two phases were independent one of another and that each was correlated to the depth of the secondary minimum of the corresponding XDLVO energy profile. Hydrophobic and electrostatic interactions governed the deposition process: short range hydrophilic repulsion prevented deposition into the primary minimum while electrostatic interactions defined the dependence of the deposition kinetics on the ionic strength. Different surfaces showed distinct kinetics of and capacities for MS2 deposition pointing to the potential of polyelectrolyte multilayers as easy-to-apply coatings for regulating virus adsorption, inactivating viruses via the virucidal action of cationic polyelectrolytes and reducing human exposure to viruses. [ABSTRACT FROM AUTHOR]

Abstract Background Simulations using fluorescent tracers can be useful in understanding the spread of pathogens and in devising effective infection control strategies. Methods During simulated patient care interactions in which providers wore gloves and gowns, we evaluated environmental and personnel dissemination of fluorescent lotion and bacteriophage MS2 from a contaminated mannequin. The frequency of skin and clothing contamination after removal of personal protective equipment (PPE) was compared before versus after an intervention that included education and practice in PPE donning and doffing. Results Ten healthcare personnel participated in 30 pre-intervention and 30 post-intervention patient care simulations. Fluorescent lotion and bacteriophage MS2 were rapidly disseminated to touched surfaces throughout the room; there was no difference in the frequency of contamination before versus after the PPE training intervention. After the intervention, there was a decrease in skin and/or clothing contamination with fluorescent lotion (9/30, 30 % versus 1/30, 3 %; P = 0.01) and bacteriophage MS2 (8/30, 27 % versus 2/30, 7 %; P = 0.08) and there was a significant reduction in the concentration of bacteriophage MS2 recovered from hands (0.31 versus 0.07 log10plaque-forming units; P

Antibody complementarity determining regions (CDRs) participate in antigen recognition, but not all participate equally in antigen binding. Here we describe a technique for discovering strong, specific binding partners to defined motifs within the CDRs of chimeric, engineered antibodies using affinity selection and counter-selection of epitopes displayed on bacteriophage MS2-based virus-like particles (VLPs). As an example, we show how this technique can be used to identify families of VLPs that interact with antibodies displaying the CDRs encoded by the germline precursor of a broadly neutralizing monoclonal antibody against HIV-1., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

We report on the preparation of electropositive nanofiber membranes by electrospinning with in situ photo-crosslinking and their preliminary evaluation in virus adsorption and removal tests. Poly(vinyl alcohol) (PVA) and polyethyleneimine (PEI) were modified with glycidyl methacrylate, to form an acrylated crosslinked polymer (a-PVA/a-PEI) upon UV exposure during the electrospinning process. The a-PVA/a-PEI nanofibers were electrospun on a non-woven polyester support to form an electropositive (ζ = 7 mV at pH 7.4) and hydrophilic ( θ w ∼ 53 ° ) membrane with the mean pore size of 0.48 μm. The microfilter had the specific permeate flux of ∼6.9 · 10 4  L/(m 2 ·h·bar), comparable with that of commercially available membranes of similar nominal pore sizes. Adsorption of the negatively charged and hydrophilic bacteriophage MS2 ( d ∼ 27   nm) onto the membrane followed Freundlich isotherm and could be classified as favorable with the average adsorption intensity n - 1 ∼ 0.91 . The 99% retention of MS2 in flow-through virus clearance tests was attributed to adsorption and was likely controlled by the limited detention time within the membrane. [ABSTRACT FROM AUTHOR]

Pathogenic viruses (e.g., Enteroviruses, Noroviruses, Rotaviruses, and Adenovirus) present in wastewater, even at low concentrations, can cause serious waterborne diseases. Improving water treatment to enhance viral removal is of paramount significance, especially given the COVID-19 pandemic. This study incorporated microwave-enabled catalysis into membrane filtration and evaluated viral removal using a model bacteriophage (MS2) as a surrogate. Microwave irradiation effectively penetrated the PTFE membrane module and enabled surface oxidation reactions on the membrane-coated catalysts (i.e., BiFeO 3), which thus elicited strong germicidal effects via local heating and radical formation as reported previously. A log removal of 2.6 was achieved for MS2 within a contact time as low as 20 s using 125-W microwave irradiation with the initial MS2 concentration of 105 PFU∙mL-1. By contrast, almost no inactivation could be achieved without microwave irradiation. COMSOL simulation indicates that the catalyst surface could be heated up to 305 oC with 125-W microwave irradiation for 20 s and also analyzed microwave penetration into catalyst or water film layers. This research provides new insights to the antiviral mechanisms of this microwave-enabled catalytic membrane filtration. [Display omitted] • Microwave catalytic membrane filtration achieved effective viral inactivation. • Microwave irradiation intensity and exposure time affects viral inactivation performances. • Generation of radicals were confirmed by EPR measurement and radical scavenging experiments. • The MS2 inactivation mechanisms under microwave heating and conventional heating are different. • COMSOL Multiphysics simulation unresolved microwave penetration and heat distribution. [ABSTRACT FROM AUTHOR]

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Background: Virus-like particles (VLPs) of the RNA bacteriophage MS2 have many potential applications in biotechnology. MS2 VLPs provide a platform for peptide display and affinity selection (i.e. biopanning). They are also under investigation as vehicles for targeted drug delivery, using display of receptor-specific peptides or nucleic acid aptamers to direct their binding to specific cell-surface receptors. However, there are few molecules more suited to the precise targeting and binding of a cellular receptor than antibodies. Results: Here we describe a strategy for display of four different functional single-chain variable fragments (scFvs) on the surface of the MS2 VLP. Each scFv is validated both for its presence on the surface of the VLP and for its ability to bind its cognate antigen. Conclusions: This work demonstrates the suitability of the MS2 VLP platform to display genetically fused scFvs, allowing for many potential applications of these VLPs and paving the way for future work with libraries of scFvs displayed in a similar manner on the VLP surface. These libraries can then be biopanned and novel scFv binders to targets can be readily discovered. [ABSTRACT FROM AUTHOR]

This research aims to check the chargeability of sodium hypochlorite and the efficacy evaluation of an air-assisted electrostatic disinfection device. Five different inanimate surfaces i.e., wood, glass, stainless steel, plastic and fabric were considered to examine the performance in terms of efficacy, survival time, off-target losses, spray coverage and the volume of disinfectant consumed. A significant charge-to-mass level of 2.43 mC/kg was achieved for sodium hypochlorite at an applied voltage of 2.0 kV, a liquid flowrate of 253 ml/min and applied air pressure of 4.0 bar. The experimental results found that 1000 mg/L of sodium hypochlorite concentration effectively eliminated Pseudomonas aeruginosa , Clostridium perfringens and Bacteriophage MS2 colonies. • Disinfection and sanitisation has become one of the most essential tasks to stop the spread of pathogenic infections. • The research work aims to check the chargeability and suitability of sodium hypochlorite as a disinfectant by using an electrostatic spraying technique. • The microorganisms namely, P. aeruigenosa , E. coli , C. prefringens and Bacteriophage MS2 were grown under laboratory conditions. • The critical performance parameters such as efficacy, survival time, off-target losses, spray coverage and the volume of disinfectant were examined. [ABSTRACT FROM AUTHOR]

• Contaminated writing utensils are a potential source for transmission of pathogens. • Colonized patients transfer methicillin-resistant Staphylococcus aureus to pens. • A novel ultraviolet light device was effective in reducing microorganisms on pens. • The device could be used to reduce the risk of transmission by shared writing utensils. Shared pens and styluses are a potential source for transmission of health care–associated pathogens and respiratory viruses in health care facilities. A novel ultraviolet light-emitting diode device was effective in reducing bacteria and viruses inoculated on pens and in reducing methicillin-resistant Staphylococcus aureus transferred to pens by colonized patients. The device could be useful in reducing the risk of transmission of pathogens by shared writing utensils. [ABSTRACT FROM AUTHOR]

Background: Simulations using fluorescent tracers can be useful in understanding the spread of pathogens and in devising effective infection control strategies. Methods: During simulated patient care interactions in which providers wore gloves and gowns, we evaluated environmental and personnel dissemination of fluorescent lotion and bacteriophage MS2 from a contaminated mannequin. The frequency of skin and clothing contamination after removal of personal protective equipment (PPE) was compared before versus after an intervention that included education and practice in PPE donning and doffing. Results: Ten healthcare personnel participated in 30 pre-intervention and 30 post-intervention patient care simulations. Fluorescent lotion and bacteriophage MS2 were rapidly disseminated to touched surfaces throughout the room; there was no difference in the frequency of contamination before versus after the PPE training intervention. After the intervention, there was a decrease in skin and/or clothing contamination with fluorescent lotion (9/30, 30 % versus 1/30, 3 %; P = 0.01) and bacteriophage MS2 (8/30, 27 % versus 2/30, 7 %; P = 0.08) and there was a significant reduction in the concentration of bacteriophage MS2 recovered from hands (0.31 versus 0.07 log10plaque-forming units; P < 0.01). Conclusions: Our findings suggest that simulations with fluorescent lotion can be a useful teaching tool to illustrate the spread of pathogens and provide further evidence that simple PPE training interventions can be effective in reducing contamination of personnel. [ABSTRACT FROM AUTHOR]

Aims State-of-the-art bioaerosol samplers have poor collection efficiencies for ultrafine virus aerosols. This work evaluated the performance of a novel growth tube collector ( GTC), which utilizes laminar-flow water-based condensation to facilitate particle growth, for the collection of airborne MS2 viruses. Methods and Results Fine aerosols (<500 nm) containing MS2 coliphage were generated from a Collison nebulizer, conditioned by a dilution dryer and collected by a GTC and a BioSampler. The GTC effectively condensed water vapour onto the virus particles, creating droplets 2-5 μm in diameter, which facilitated collection. Comparison of particle counts upstream and downstream revealed that the GTC collected >93% of the inlet virus particles, whereas the BioSampler's efficiency was about 10%. Viable counts of the GTC-collected viruses were also one order of magnitude higher than those of the BioSampler ( P = 0·003). Conclusion The efficiency of the GTC for the viable collection of MS2 viruses exceeds that of industry standard instrument, the BioSampler, by a factor of 10-100. Significance and Impact of the Study This study reveals that the GTC is an effective collector of viable MS2 aerosols, and concludes the instrument will be an effective tool for studying viable virus aerosols and the inhalation risks posed by airborne viruses. [ABSTRACT FROM AUTHOR]