Residual viral and bacterial contamination of surfaces after cleaning and disinfection

Bovine Digital Dermatitis: Treponema spp. on trimming equipment and chutes - effect of washing and disinfection

BACKGROUND

Digital dermatitis (DD) is a contagious bovine foot disease causing reduced animal welfare and negative economic consequences for the farmer. Treponema spp. are the most important causative agents. Studies indicate that trimming equipment can transfer DD-associated treponemes between cows. The aim of this observational study in 22 DD-positive Norwegian dairy herds was to investigate the risk of transferring Treponema spp. with trimming equipment and chutes after claw trimming, and after washing and disinfection. Swabs from the trimming equipment and chutes were collected from nine different locations, at five different time points. Bacterial DNA was extracted from 647 swabs and analysed by qPCR for Treponema spp. In addition, 172 swabs taken immediately after trimming, were analysed by a multiplex qPCR targeting T. phagedenis, T. pedis and T. medium/vincentii. Biopsy sampling from DD lesions was performed on cows in the same herds during trimming. Altogether 109 biopsies were analysed by FISH for confirmation of the DD diagnosis and identification of Treponema phylotypes (PTs).

RESULTS

High numbers of Treponema spp. were detected from all nine locations on the trimming equipment and chutes immediately after trimming, and T. phagedenis was detected on two or more locations in all but two herds, 1 and 19. There was a decline in the amount of Treponema spp. after washing and disinfection. The belly belt, the cuff, and the footrest on the chute had the highest proportion of positive samples after disinfection. The belly belt had the highest copy numbers of all nine locations (median = 7.9, max = 545.1). No Treponema spp. was detected on the hoof knives after disinfection. Treponema phagedenis, T. pedis, and Treponema phylotype 3 (T. refringens) were detected by FISH analysis of the biopsies. Treponema phagedenis was detected in biopsies from all herds except 1 and 19.

CONCLUSION

This study shows that DD-associated Treponema spp. were present on the trimming equipment and chutes after trimming cows in DD-positive herds. Washing and disinfection reduced the load of Treponema spp. However, large differences in Treponema spp. between different locations were documented. High copy numbers on the grinder and the chute after disinfection, indicates that sufficient cleaning and disinfection of these locations is difficult, and that passive transfer of DD-associated treponemes (viable or not) is possible.

Hygiene requirements for cleaning and disinfection of surfaces: recommendation of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute

This recommendation of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) addresses not only hospitals, but also outpatient health care facilities and compiles current evidence. The following criteria are the basis for the indications for cleaning and disinfection: Infectious bioburden and tenacity of potential pathogens on surfaces and their transmission routes, influence of disinfecting surface cleaning on the rate of nosocomial infections, interruption of cross infections due to multidrug-resistant organisms, and outbreak control by disinfecting cleaning within bundles. The criteria for the selection of disinfectants are determined by the requirements for effectiveness, the efficacy spectrum, the compatibility for humans and the environment, as well as the risk potential for the development of tolerance and resistance. Detailed instructions on the organization and implementation of cleaning and disinfection measures, including structural and equipment requirements, serve as the basis for their implementation. Since the agents for surface disinfection and disinfecting surface cleaning have been classified as biocides in Europe since 2013, the regulatory consequences are explained. As possible addition to surface disinfection, probiotic cleaning, is pointed out. In an informative appendix (only in German), the pathogen characteristics for their acquisition of surfaces, such as tenacity, infectious dose and biofilm formation, and the toxicological and ecotoxicological characteristics of microbicidal agents as the basis for their selection are explained, and methods for the evaluation of the resulting quality of cleaning or disinfecting surface cleaning are presented.

Virus on surfaces: Chemical mechanism, influence factors, disinfection strategies, and implications for virus repelling surface design

While SARS-CoV-2 is generally under control, the question of variants and infections still persists. Fundamental information on how the virus interacts with inanimate surfaces commonly found in our daily life and when in contact with the skin will be helpful in developing strategies to inhibit the spread of the virus. Here in, a critically important review of current understanding of the interaction between virus and surface is summarized from chemistry point-of-view. The Derjaguin-Landau-Verwey-Overbeek and extended Derjaguin-Landau-Verwey-Overbeek theories to model virus attachments on surfaces are introduced, along with the interaction type and strength, and quantification of each component. The virus survival and transfer are affected by a combination of biological, physical, and chemical parameters, as well as environmental parameters. The surface properties for virus and virus survival on typical surfaces such as metals, plastics, and glass are summarized. Attention is also paid to the transfer of virus to/from surfaces and skin. Typical virus disinfection strategies utilizing heat, light, chemicals, and ozone are discussed together with their disinfection mechanism. In the last section, design principles for virus repelling surface chemistry such as surperhydrophobic or surperhydrophilic surfaces are also introduced, to demonstrate how the integration of surface property control and advanced material fabrication can lead to the development of functional surfaces for mitigating the effect of viral infection upon contact.

Microbiome and virome on indoor surfaces of an Antarctic research ship

BACKGROUND

Few studies have focused on microbial diversity in indoor environments of ships, as well as the role of the microbiome and its ecological interconnections. In this study, we investigated the microbiome and virome present on the internal surfaces of a polar ship in different stages (beginning, during, and at the end) of the Brazilian Antarctic expedition in order to evaluate abundance of microorganisms in different periods.

OBJECTIVES AND METHODS

We used shotgun metagenomic analysis on pooled samples from sampling surfaces in the ship's interior to track the microbial diversity.

FINDINGS

Considering the total fraction of the microbiome, the relative abundance of bacteria, eukaryotes, viruses, and archaea was 83.7%, 16.2%, 0.04%, and 0.002%, respectively. Proteobacteria was the most abundant bacterial phyla, followed by Firmicutes, Actinobacteria, and Bacteroidetes. Concerning the virome, the greatest richness of viral species was identified during the middle of the trip, including ten viral families after de novo assembly: Autographiviridae, Chrysoviridae, Genomoviridae, Herelleviridae, Myoviridae, Partitiviridae, Podoviridae, Potyviridae, Siphoviridae, and Virgaviridae.

MAIN CONCLUSIONS

This study contributed to the knowledge of microbial diversity in naval transportation facilities, and variations in the abundance of microorganisms probably occurred due to factors such as the number of passengers and activities on the ship.

Disinfection of Phi6, MS2, and Escherichia coli by Natural Sunlight on Healthcare Critical Surfaces

Ultraviolet (UV) radiation systems, commonly used to disinfect surfaces, drinking water, and air, stem from historical practice to use sunlight to disinfect household items after contagious illness. Currently, it is still recommended in viral outbreak contexts such as COVID-19, Ebola, and Marburg to expose soft surfaces to sunlight after washing with detergent or disinfecting with chlorine. However, sunlight that reaches the Earth's surface is in the UVA/UVB wavelengths, whereas UV disinfection systems typically rely on biocidal UVC. Our goal was to fill the evidence gap on the efficacy of sunlight disinfection on surface materials common in low-resource healthcare settings by seeding four surfaces (stainless steel, nitrile, tarp, cloth) with three microorganisms (viral surrogate bacteriophages Phi6 and MS2 and Escherichia coli bacteria), with and without soil load, and exposing to three sunlight conditions (full sun, partial sun, cloudy). We conducted 144 tests in triplicate and found: solar radiation averaged 737 W/m2 (SD = 333), 519 W/m2 (SD = 65), and 149 W/m2 (SD = 24) for full sun, partial sun, and cloudy conditions; significantly more surfaces averaged ≥ 4 log10 reduction value (LRV) for Phi6 than MS2 and E. coli (P < 0.001) after full sun exposure, and no samples achieved ≥ 4 LRV for partial sun or cloudy conditions. On the basis of our results, we recommend no change to current protocols of disinfecting materials first with a 0.5% chlorine solution then moving to sunlight to dry. Additional field-based research is recommended to understand sunlight disinfection efficacy against pathogenic organisms on healthcare relevant surfaces during actual outbreak contexts.

Assessment of a novel continuous cleaning device using metatranscriptomics in diverse hospital environments

Introduction

Despite routine implementation of cleaning and disinfection practices in clinical healthcare settings, high-touch environmental surfaces and contaminated equipment often serve as reservoirs for the transmission of pathogens associated with healthcare-associated infections (HAIs).

Methods

The current study involved the analysis of high-touch surface swabs using a metatranscriptomic sequencing workflow (CSI-Dx™) to assess the efficacy of cleanSURFACES® technology in decreasing microbial burden by limiting re-contamination. This is a non-human single center study conducted in the Emergency Department (ED) and on an inpatient Oncology Ward of Walter Reed National Military Medical Center that have followed hygienic practices during the COVID-19 pandemic environment.

Results

Although there was no difference in observed microbial richness (two-tailed Wilcoxon test with Holm correction, P > 0.05), beta diversity findings identified shifts in microbial community structure between surfaces from baseline and post-intervention timepoints (Day 1, Day 7, Day 14, and Day 28). Biomarker and regression analyses identified significant reductions in annotated transcripts for various clinically relevant microorganisms' post-intervention, coagulase-negative staphylococci and Malassezia restricta, at ED and Oncology ward, respectively. Additionally, post-intervention samples predominantly consisted of Proteobacteria and to a lesser extent skin commensals and endogenous environmental microorganisms in both departments.

Discussion

Findings support the value of cleanSURFACES®, when coupled with routine disinfection practices, to effectively impact on the composition of active microbial communities found on high-touch surfaces in two different patient care areas of the hospital (one outpatient and one inpatient) with unique demands and patient-centered practices.

Feeding Our Microbiota: Stimulation of the Immune/Semiochemical System and the Potential Amelioration of Non-Communicable Diseases

Non-communicable diseases are those conditions to which causative infectious agents cannot readily be assigned. It is increasingly likely that at least some of these conditions are due to the breakdown of the previously mutualistic intestinal microbiota under the influence of a polluted, biocide-rich, environment. Following the mid-20th century African studies of Denis Burkitt, the environmental cause of conditions such as obesity has been ascribed to the absence of sufficient fibre in the modern diet, however in itself that is insufficient to explain the parallel rise of problems with both the immune system and of mental health. Conversely, Burkitt himself noted that the Maasai, a cattle herding people, remained healthy even with their relatively low intake of dietary fibre. Interestingly, however, Burkitt also emphasised that levels of non-communicable disease within a population rose as faecal weight decreased significantly, to about one third of the levels found in healthy populations. Accordingly, a more cogent explanation for all the available facts is that the fully functioning, adequately diverse microbiome, communicating through what has been termed the microbiota–gut–brain axis, helps to control the passage of food through the digestive tract to provide itself with the nutrition it needs. The method of communication is via the production of semiochemicals, interkingdom signalling molecules, potentially including dopamine. In turn, the microbiome aids the immune system of both adult and, most importantly, the neonate. In this article we consider the role of probiotics and prebiotics, including fermented foods and dietary fibre, in the stimulation of the immune system and of semiochemical production in the gut lumen. Finally, we reprise our suggestion of an ingestible sensor, calibrated to the detection of such semiochemicals, to assess both the effectiveness of individual microbiomes and methods of amelioration of the associated non-communicable diseases.

Chlorine efficacy against bacteriophage Phi6, a surrogate for enveloped human viruses, on porous and non-porous surfaces at varying temperatures and humidity

While efficacy of chlorine against Phi6, a widely-used surrogate for pathogenic enveloped viruses, is well-documented, surfaces common to low-resource contexts are under-researched. We evaluated seven surfaces (stainless steel, plastic, nitrile, tarp, cloth, concrete, wood) and three environmental conditions-temperature (4, 25, 40 °C), relative humidity (RH) (23, 85%), and soiling-to determine Phi6 recoverability and the efficacy of disinfection with 0.5% NaOCl. Overall, Phi6 recovery was >4 log₁₀ PFU/mL on most surfaces after drying 1 hour at all temperature/humidity conditions. After disinfection, all non-porous test conditions (48/48) achieved ≥4 LRV at 1 and 5 minutes of exposure; significantly more non-porous surfaces met ≥4 LRV than porous (p < 0.001). Comparing porous surfaces, significantly fewer wood samples met ≥4 LRV than cloth (p < 0.001); no differences were observed between concrete and either wood (p = 0.083) or cloth (p = 0.087). Lastly, no differences were observed between soil and no-soil conditions for all surfaces (p = 0.712). This study highlights infectious Phi6 is recoverable across a range of surfaces and environmental conditions, and confirms the efficacy of chlorine disinfection. We recommend treating all surfaces with suspect contamination as potentially infectious, and disinfecting with 0.5% NaOCl for the minimum contact time required for the target enveloped virus (e.g. Ebola, SARS-CoV-2).

Evaluation of surface disinfection methods to inactivate the beta coronavirus Murine Hepatitis Virus

The list of EPA-approved disinfectants for coronavirus features many products for use on hard, non-porous materials. There are significantly fewer products registered for use on porous materials. Further, many common, high-touch surfaces fall in between non-porous materials such as glass and porous materials such as soft fabrics. The objective of this study was to assess the efficacy of selected commercially available disinfectant products against coronaviruses on common, high-touch surfaces. Four disinfectants (Clorox Total 360, Bleach solution, Vital Oxide, and Peroxide Multi-Surface Cleaner) were evaluated against Murine Hepatitis Virus A59 (MHV) as a surrogate coronavirus for SARS-CoV-2. MHV in cell culture medium was inoculated onto four materials: stainless steel, latex-painted drywall tape, Styrene Butadiene rubber (rubber), and bus seat fabric. Immediately (T0) or 2-hr (T2) post-inoculation, disinfectants were applied by trigger-pull or electrostatic sprayer and either held for recommended contact times (Spray only) or immediately wiped (Spray and Wipe). Recovered infectious MHV was quantified by median tissue culture infectious dose assay. Bleach solution, Clorox Total 360, and Vital Oxide were all effective (>3-log₁₀ reduction or complete kill of infectious virus) with both the Spray Only and Spray and Wipe methods on stainless steel, rubber, and painted drywall tape when used at recommended contact times at both T0 and T2 hr. Multi-Surface Cleaner unexpectedly showed limited efficacy against MHV on stainless steel within the recommended contact time; however, it showed increased (2.3 times greater efficacy) when used in the Spray and Wipe method compared to Spray Only. The only products to achieve a 3-log₁₀ reduction on fabric were Vital Oxide and Clorox Total 360; however, the efficacy of Vital Oxide against MHV on fabric was reduced to below 3-log₁₀ when applied by an electrostatic sprayer compared to a trigger-pull sprayer. This study highlights the importance of considering the material, product, and application method when developing a disinfection strategy for coronaviruses on high-touch surfaces.

A Review on Building Design as a Biomedical System for Preventing COVID-19 Pandemic

Sustainable design methods aim to obtain architectural solutions that assure the coexistence and welfare of human beings, inorganic structures, and living things that constitute ecosystems. The novel coronavirus emergence, inadequate vaccines against the present severe acute respiratory syndrome-coronavirus-(SARS-CoV-2), and increases in microbial resistance have made it essential to review the preventative approaches used during pre-antibiotic periods. Apart from low carbon emissions and energy, sustainable architecture for facilities, building designs, and digital modeling should incorporate design approaches to confront the impacts of communicable infections. This review aims to determine how architectural design can protect people and employees from harm; it models viewpoints to highlight the architects’ roles in combating coronavirus disease 2019 (COVID-19) and designing guidelines as a biomedical system for policymakers. The goals include exploring the hospital architecture evolution and the connection between architectural space and communicable infections and recommending design and digital modeling strategies to improve infection prevention and controls. Based on a wide-ranging literature review, it was found that design methods have often played important roles in the prevention and control of infectious diseases and could be a solution for combating the wide spread of the novel coronavirus or coronavirus variants or delta.

Anti-pathogen stainless steel combating COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibits strong stability on conventional stainless steel (SS) surface, with infectious virus detected even after two days, posing a high risk of virus transmission via surface touching in public areas. In order to mitigate the surface toughing transmission, the present study develops the first SS with excellent anti-pathogen properties against SARS-COV-2. The stabilities of SARS-CoV-2, H1N1 influenza A virus (H1N1), and Escherichia coli (E.coli) on the surfaces of Cu-contained SS, pure Cu, Ag-contained SS, and pure Ag were investigated. It is discovered that pure Ag and Ag-contained SS surfaces do not display apparent inhibitory effects on SARS-CoV-2 and H1N1. In comparison, both pure Cu and Cu-contained SS with a high Cu content exhibit significant antiviral properties. Significantly, the developed anti-pathogen SS with 20 wt% Cu can distinctly reduce 99.75% and 99.99% of viable SARS-CoV-2 on its surface within 3 and 6 h, respectively. In addition, the present anti-pathogen SS also exhibits an excellent inactivation ability for H1N1 influenza A virus (H1N1), and Escherichia coli (E.coli). Interestingly, the Cu ion concentration released from the anti-pathogen SS with 10 wt% and 20 wt% Cu was notably higher than the Ag ion concentration released from Ag and the Ag-contained SS. Lift buttons made of the present anti-pathogen SS are produced using mature powder metallurgy technique, demonstrating its potential applications in public areas and fighting the transmission of SARS-CoV-2 and other pathogens via surface touching.

Impeding the Medical Protective Clothing Contamination by a Spray Coating of Trifunctional Polymers

The risk of fomite-mediated transmission in the clinic is substantially increasing amid the recent COVID-19 pandemic as personal protective equipment (PPE) of hospital workers is easily contaminated by direct contact with infected patients. In this context, it is crucial to devise a means to reduce such transmission. Herein, we report an antimicrobial, antiviral, and antibiofouling trifunctional polymer that can be easily coated onto the surface of medical protective clothing to effectively prevent pathogen contamination on the PPE. The coating layer is formed on the surfaces of PPE by the simple spray coating of an aqueous solution of the trifunctional polymer, poly(dodecyl methacrylate (DMA)-poly(ethylene glycol) methacrylate (PEGMA)-quaternary ammonium (QA)). To establish an optimal ratio of antifouling and antimicrobial functional groups, we performed antifouling, antibacterial, and antiviral tests using four different ratios of the polymers. Antifouling and bactericidal results were assessed using Staphylococcus aureus, a typical pathogenic bacterium that induces an upper respiratory infection. Regardless of the molar ratio, polymer-coated PPE surfaces showed considerable antiadhesion (∼65-75%) and antibacterial (∼75-87%) efficacies soon after being in contact with pathogens and maintained their capability for at least 24 h, which is sufficient for disposable PPEs. Further antiviral tests using coronaviruses showed favorable results with PPE coated at two specific ratios (3.5:6:0.5 and 3.5:5.5:1) of poly(DMA-PEGMA-QA). Moreover, biocompatibility assessments using the two most effective polymer ratios showed no recognizable local or systemic inflammatory responses in mice, suggesting the potential of this polymer for immediate use in the field.

An assessment of the health risks associated with shared sanitation: a case study of the community ablution blocks in Durban, South Africa

Shared sanitation facilities have been hailed as an innovative approach to solve the challenge with sanitation access. However, these facilities may act as hotspots for disease transmission due to unhygienic conditions. In this study we used quantitative (based on Escherichia coli contamination) techniques to assess the health risks associated with the use of community ablution blocks (CABs). The most contaminated surfaces were the cistern handle (5.7 Log₁₀ cfu/cm²) and internal pull latch (5.8 Log₁₀ cfu/cm²). Based on the E. coli contamination, at least two people out of 100 CAB users might be potentially infected when they touch "hot" surfaces. These risks were modelled assuming transfer of potentially pathogenic E. coli from these surfaces to the mouth. The incorporation of risk-reduction measures, such as wiping of these surfaces or washing of hands, could potentially result in significant reduction of infection risks. The most significant risk-reduction intervention was determined to be wiping of the contact surfaces, especially twice prior to contact. A combination of risk-reduction interventions could further reduce the risks. This study shows that contamination of contact surfaces within shared CABs could lead to increased risks of infections, requiring measures aimed at reducing the associated risks. The risk assessment framework used in this study could therefore be applied in similar settings to estimate associated health risks with the use of such facilities.

Advanced descriptors for long-range noncovalent interactions between SARS-CoV-2 spikes and polymer surfaces

The recent pandemic triggered numerous societal efforts aimed to control and limit the spread of SARS-CoV-2. One of these aspects is related on how the virion interacts with inanimate surfaces, which might be the source of secondary infection. Although recent works address the adsorption of the spike protein on surfaces, there is no information concerning the long-range interactions between spike and surfaces, experimented by the virion when is dispersed in the droplet before its possible adsorption. Some descriptors, namely the interaction potentials per single protein and global potentials, were calculated in this work. These descriptors, evaluated for the closed and open states of the spike protein, are correlated to the long-range noncovalent interactions between the SARS-CoV-2 spikes and polymeric surfaces. They are associated with the surface's affinity towards SARS-CoV-2 dispersed in respiratory droplets or water solutions. Molecular-Dynamics simulations were performed to model the surface of three synthetic polymeric materials: Polypropylene (PP), Polyethylene Terephthalate (PET), and Polylactic Acid (PLA), used in Molecular Mechanics simulations to define the above potentials. The descriptors show a similar trend for the three surfaces, highlighting a greater affinity towards the spikes of PP and PLA over PET. For closed and open structures, the long-range interactions with the surfaces decreased in the following order PP ∼ PLA > PET and PLA > PP > PET, respectively. Thus, PLA and PP interact with the virion quite distant from these surfaces to a greater extent concerning the PET surface, however, the differences among the considered surfaces were small. The global potentials show that the long-range interactions are weak compared to classic binding energy of covalent or ionic bonds. The proposed descriptors are useful most of all for a comparative study aimed at quickly preliminary screening of polymeric surfaces. The obtained results should be validated by more accurate method which will be subject of a subsequent work.

Selection of a SARS-CoV-2 Surrogate for Use in Surface Disinfection Efficacy Studies with Chlorine and Antimicrobial Surfaces

Initial recommendations for surface disinfection to prevent SARS-CoV-2 transmission were developed using previous evidence from potential surrogates. To the best of our knowledge, no appropriate surrogate for SARS-CoV-2 has been identified or confirmed for chlorine and antimicrobial surface disinfection. We completed a study to evaluate the efficacy of two hypothesized antimicrobial surfaces, and four chlorine solutions on nonporous and porous surfaces, against SARS-CoV-2 and three potential SARS-CoV-2 surrogates [coronavirus mouse hepatitis virus (MHV) and bacteriophages Phi6 and MS2], to identify a BSL-1 or BSL-2 virus to use in future studies. We found SARS-CoV-2 can be reduced >4 log10 on porous and nonporous surfaces within 30 s upon exposure to 0.5% NaOCl. The results indicate coronavirus MHV-GFP is inactivated faster than SARS-CoV-2 (MHV-GFP ≥ 6.08 log10; SARS-CoV-2 = 0.66 log10 at 30 s with 0.05% NaOCl on steel) and MS2 is inactivated more slowly. Phi6 is inactivated like SARS-CoV-2, and we propose Phi6 as a slightly conservative surrogate for SARS-CoV-2 chlorine disinfection. Additionally, disinfection of bacteriophages on wood was challenging, and exposure to antimicrobial surfaces had no disinfection efficacy as tested. We recommend using 0.5% chlorine on surfaces for a minimum of 30 s of contact to disinfect SARS-CoV-2 and recommend additional research on Phi6 disinfection with varied surfaces and conditions.

Detection of SARS-CoV-2 RNA on contact surfaces within shared sanitation facilities

Contamination of contact surfaces with SARS-CoV-2 has been reported as a potential route for the transmission of COVID-19. This could be a major issue in developing countries where access to basic sanitation is poor, leading to the sharing of toilet facilities. In this study, we report SARS-CoV-2 contamination of key contact surfaces in shared toilets and the probabilistic risks of COVID-19 infections based on detection and quantification of the nucleic acid on the surfaces. We observed that 54-69% of the contact surfaces were contaminated, with SARS-CoV-2 loads ranging from 28.1 to 132.7 gene copies per cm². Toilet seats had the highest contamination, which could be attributed to shedding of the virus in feces and urine. We observed a significant reduction in viral loads on the contaminated surfaces after cleaning, showing the potential of effective cleaning on the reduction of contamination. The pattern of contamination indicates that the most contaminated surfaces are those that are either commonly touched by users of the shared toilets or easily contaminated with feces and urine. These surfaces were the toilet seats, cistern handles and tap handles. The likelihood (probability) of infection with COVID-19 on these surfaces was highest on the toilet seat (1.76 × 10^-4(1.58 × 10^-6)) for one time use of the toilet. These findings highlight the potential risks for COVID-19 infections in the event that intact infectious viral particles are deposited on these contact surfaces. Therefore, this study shows that shared toilet facilities in densely populated areas could lead to an increase in risks of COVID-19 infections. This calls for the implementation of risk reduction measures, such as regular washing of hands with soap, strict adherence to wearing face masks, and effective and regular cleaning of shared facilities.

Detection of SARS-CoV-2 RNA on contact surfaces within shared sanitation facilities

Contamination of contact surfaces with SARS-CoV-2 has been reported as a potential route for the transmission of COVID-19. This could be a major issue in developing countries where access to basic sanitation is poor, leading to the sharing of toilet facilities. In this study, we report SARS-CoV-2 contamination of key contact surfaces in shared toilets and the probabilistic risks of COVID-19 infections based on detection and quantification of the nucleic acid on the surfaces. We observed that 54-69% of the contact surfaces were contaminated, with SARS-CoV-2 loads ranging from 28.1 to 132.7 gene copies per cm². Toilet seats had the highest contamination, which could be attributed to shedding of the virus in feces and urine. We observed a significant reduction in viral loads on the contaminated surfaces after cleaning, showing the potential of effective cleaning on the reduction of contamination. The pattern of contamination indicates that the most contaminated surfaces are those that are either commonly touched by users of the shared toilets or easily contaminated with feces and urine. These surfaces were the toilet seats, cistern handles and tap handles. The likelihood (probability) of infection with COVID-19 on these surfaces was highest on the toilet seat (1.76 × 10^-4(1.58 × 10^-6)) for one time use of the toilet. These findings highlight the potential risks for COVID-19 infections in the event that intact infectious viral particles are deposited on these contact surfaces. Therefore, this study shows that shared toilet facilities in densely populated areas could lead to an increase in risks of COVID-19 infections. This calls for the implementation of risk reduction measures, such as regular washing of hands with soap, strict adherence to wearing face masks, and effective and regular cleaning of shared facilities.

A systematic review of chlorine-based surface disinfection efficacy to inform recommendations for low-resource outbreak settings

Background

Infectious diseases can be transmitted via fomites (contaminated surfaces/objects); disinfection can interrupt this transmission route. However, disinfection guidelines for low-resource outbreak settings are inconsistent and not evidence-based.

Methods

A systematic review of surface disinfection efficacy studies was conducted to inform low-resource outbreak guideline development. Due to variation in experimental procedures, outcomes were synthesized in a narrative summary focusing on chlorine-based disinfection against 7 pathogens with potential to produce outbreaks in low-resource settings (Mycobacterium tuberculosis, Vibrio cholerae, Salmonella spp., hepatitis A virus, rotavirus, norovirus, and Ebola virus).

Results

Data were extracted from 89 laboratory studies and made available, including 20 studies on relevant pathogens used in combination with surrogate data to determine minimum target concentration × time (“CT”) factors. Stainless steel (68%) and chlorine-based disinfectants (56%) were most commonly tested. No consistent trend was seen in the influence of chlorine concentration and exposure time on disinfection efficacy. Disinfectant application mode; soil load; and surface type were frequently identified as influential factors in included studies.

Conclusions

This review highlights that surface disinfection efficacy estimates are strongly influenced by each study's experimental conditions. We therefore recommend laboratory testing to be followed by field-based testing/monitoring to ensure effectiveness is achieved in situ.

Hygiene management in newborn individually housed dairy calves focusing on housing and feeding practices

In calf rearing, the first weeks of life are critical and associated with the highest mortality due to enteric and respiratory diseases. A well-implemented hygiene management can help to protect calves' health preventively by reducing the load of pathogenic bacteria and interrupting infection chains. The aim of this study was to identify deficiencies in hygiene management of individually housed dairy calves by surveying current practice and examining feeding and housing equipment with different hygiene indicators. On 11 farms, different locations in 2 pens or hutches for individual calf rearing prepared for restocking and 2 feeding buckets per farm, including the inner and outer surfaces of artificial teats, were visually scored for cleanliness and sampled with swabs (housing equipment: n = 167; feeding equipment: n = 120). The sanitation of floors was tested with sock samples (n = 41). A total of 328 samples were analyzed for adenosine triphosphate (ATP) and protein residues, aerobic total viable count (TVC), total coliform count (TCC), Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase-producing bacteria (ESBL), and Salmonella spp. After evaluation of these results, the farmers were informed about the findings and trained on improvement in hygiene management personally. The sampling was repeated after 1 year to detect possible changes in hygiene management. The highest bacterial loads (TVC, TCC, and E. coli) were observed in feeding equipment, especially the inner teat of milk feeding buckets. Environmental samples, primarily the sidewalls and back walls of tested pens and hutches, exhibited the lowest bacterial counts and ATP and protein residues. All samples were negative for MRSA and Salmonella spp. In 10.5% of all samples, ESBL was detected, and in 6.8%, ESBL E. coli was detected, predominately in sock samples, followed by feeding equipment samples. Training in hygiene management showed only limited effects. In conclusion, there is still great potential to improve the implementation of hygiene measures in individual calf housing. In particular, more attention should be paid to the cleaning of feeding buckets and artificial teats, as this is a simple means of interrupting the possible spread of pathogens among calves.

A review of wipes used to disinfect hard surfaces in health care facilities

BACKGROUND

Despite a plethora of wipes available for use in health care facilities, there is a paucity of articles describing wipe composition, potential interactions between wipes and disinfectants, the manner in which wipes are used, and their relative efficacy. The purpose of this article is to provide an in-depth review of wipes used for disinfection of hard surfaces in health care settings.

METHODS

Comprehensive searches of the Pubmed database and Internet were conducted, and articles published from 1953 through September 2019 and pertinent on-line documents were reviewed. Bibliographies of relevant articles were reviewed.

RESULTS

Wipes vary considerably in their composition, and the disinfectants with which they are used. With reusable dry wipes, the ratio of wipe material to disinfectant and the amount of disinfectant absorbed by the wipe and delivered to surfaces is difficult to standardize, which may affect their efficacy. The manner in which wipes are used by health care personnel is highly variable, due in part to insufficient instructions for use and inadequate education of relevant personnel.

CONCLUSIONS

Additional research is needed regarding the best practices for using different types of wipes, improved methods for educating staff, and establishing the relative efficacy of wipes in reducing environmental contamination and health care-associated infections.

Laboratory efficacy of surface disinfection using chlorine against Vibrio cholerae

Disinfecting surfaces with chlorine is commonly conducted in cholera outbreaks to prevent ongoing fomite-based transmission, yet evidence gaps have led to contradictory guidance. In this study, we tested the efficacy of spraying and wiping chlorine on five representatives non-porous and five porous surfaces to remove Vibrio cholerae. In total, 120 disinfection tests were run in replicate on carriers inoculated with 1.02 × 10⁷-1.73 × 10⁸ V. cholerae CFU/cm². Surfaces disinfected by spraying 0.2% chlorine had >3 log reduction value (LRV) on 7/10 and 9/10 surfaces at 1 and 10 min, respectively; and 2.0% chlorine on 9/10 and 10/10 surfaces at 1 and 10 min, respectively. Surfaces disinfected by wiping 0.2% chlorine had >3 LRV on 3/10 and 7/10 surfaces at 1 and 10 min, respectively; and 2.0% chlorine on 8/10 surfaces at 1 and 10 min. We found no significant differences between chlorine types (p < 0.05), higher reductions with spraying compared to wiping (p = 0.001), and lower reductions on porous compared to non-porous surfaces (p = 0.006 spraying and p < 0.001 wiping). Our results support using 0.2% chlorine sprayed on all surfaces, or wiped on most non-heavily soiled surfaces, and a 2.0% concentration on contaminated porous surfaces; and emphasize surfaces must be visibly wetted to achieve disinfection.

Effect of Exposure to Chlorhexidine Residues at "During Use" Concentrations on Antimicrobial Susceptibility Profile, Efflux, Conjugative Plasmid Transfer, and Metabolism of Escherichia coli

There is no standardized protocol to predict the concentration levels of microbicides that are left on surfaces as a result of the use of these products, and there is no standardized method to predict the potential risk that such levels pose to emerging antibacterial resistance. The ability to distinguish between selection and adaption processes for antimicrobial resistance in bacteria and the impact of different concentrations of microbicide exposure have not been fully investigated to date. This study considers the effect of exposure to a low concentration of chlorhexidine digluconate (CHX) on selected phenotypes of Escherichia coli and relates the findings to the risk of emerging antimicrobial resistance. A concentration of 0.006 mg/ml CHX is a realistic "during use" exposure concentration measured on surfaces. At this concentration, it was possible for CHX-susceptible bacteria to survive, adapt through metabolic alterations, exhibit a transient decrease in antimicrobial susceptibility, and express stable clinical cross-resistance to front-line antibiotics. Efflux activity was present naturally in tested isolates, and it increased in the presence of 0.00005 mg/ml CHX but ceased with 0.002 mg/ml CHX. Phenotypic microarray assays highlighted a difference in metabolic regulation at 0.00005 mg/ml and 0.002 mg/ml CHX; more changes occurred after growth with the latter concentration. Metabolic phenotype changes were observed for substrates involved with the metabolism of some amino acids, cofactors, and secondary metabolites. It was possible for one isolate to continue transferring ampicillin resistance in the presence of 0.00005 mg/ml CHX, whilst 0.002 mg/ml CHX prevented conjugative transfer. In conclusion, E. coli phenotype responses to CHX exposure are concentration dependent, with realistic residual CHX concentrations resulting in stable clinical cross-resistance to antibiotics.

Surface Wiping Test to Study Biocide -Cinnamaldehyde Combination to Improve Efficiency in Surface Disinfection

Disinfection is crucial to control and prevent microbial pathogens on surfaces. Nonetheless, disinfectants misuse in routine disinfection has increased the concern on their impact on bacterial resistance and cross-resistance. This work aims to develop a formulation for surface disinfection based on the combination of a natural product, cinnamaldehyde, and a widely used biocide, cetyltrimethylammonium bromide. The wiping method was based on the Wiperator test (ASTM E2967−15) and the efficacy evaluation of surface disinfection wipes test (EN 16615:2015). After formulation optimization, the wiping of a contaminated surface with 6.24 log₁₀ colony-forming units (CFU) of Escherichia coli or 7.10 log₁₀ CFU of Staphylococcus aureus led to a reduction of 4.35 log₁₀ CFU and 4.27 log₁₀ CFU when the wipe was impregnated with the formulation in comparison with 2.45 log₁₀ CFU and 1.50 log₁₀ CFU as a result of mechanical action only for E. coli and S. aureus, respectively. Furthermore, the formulation prevented the transfer of bacteria to clean surfaces. The work presented highlights the potential of a combinatorial approach of a classic biocide with a phytochemical for the development of disinfectant formulations, with the advantage of reducing the concentration of synthetic biocides, which reduces the potentially negative environmental and public health impacts from their routine use.

The Influence of Surface Topography and Wettability on Escherichia coli Removal from Polymeric Materials in the Presence of a Blood Conditioning Film

The reduction of biofouling and the reduction of cross-contamination in the food industry are important aspects of safety management systems. Polymeric surfaces are used extensively throughout the food production industry and therefore ensuring that effective cleaning regimes are conducted is vital. Throughout this study, the influence of the surface characteristics of three different polymeric surfaces, polytetrafluoroethylene (PTFE), poly(methyl methacrylate) (PMMA) and polyethylene terephthalate (PET), on the removal of Escherichia coli using a wipe clean method utilising 3% sodium hypochlorite was determined. The PTFE surfaces were the roughest and demonstrated the least wettable surface (118.8°), followed by the PMMA (75.2°) and PET surfaces (53.9°). Following cleaning with a 3% sodium hypochlorite solution, bacteria were completely removed from the PTFE surfaces, whilst the PMMA and PET surfaces still had high numbers of bacteria recovered (1.2 × 107 CFU/mL and 6.3 × 107 CFU/mL, respectively). When bacterial suspensions were applied to the surfaces in the presence of a blood conditioning film, cleaning with sodium hypochlorite demonstrated that no bacteria were recovered from the PMMA surface. However, on both the PTFE and PET surfaces, bacteria were recovered at lower concentrations (2.0 × 102 CFU/mL and 1.3 × 103 CFU/mL, respectively). ATP bioluminescence results demonstrated significantly different ATP concentrations on the surfaces when soiled (PTFE: 132 relative light units (RLU), PMMA: 80 RLU and PET: 99 RLU). Following cleaning, both in the presence and absence of a blood conditioning film, all the surfaces were considered clean, producing ATP concentrations in the range of 0-2 RLU. The results generated in this study demonstrated that the presence of a blood conditioning film significantly altered the removal of bacteria from the polymeric surfaces following a standard cleaning regime. Conditioning films which represent the environment where the surface is intended to be used should be a vital part of the test regime to ensure an effective disinfection process.

An Overview of the World Current and Future Assessment of Novel COVID-19 Trajectory, Impact, and Potential Preventive Strategies at Healthcare Settings

This study is an overview of the current and future trajectory, as well as the impact of the novel Coronavirus (COVID-19) in the world and selected countries including the state of Kuwait. The selected countries were divided into two groups: Group A (China, Switzerland, and Ireland) and Group B (USA, Brazil, and India) based on their outbreak containment of this virus. Then, the actual data for each country were fitted to a regression model utilizing the excel solver software to assess the current and future trajectory of novel COVID-19 and its impact. In addition, the data were fitted using the Susceptible-Infected-Recovered (SIR) Model. The Group A trajectory showed an "S" shape trend that suited a logistic function with r² > 0.97, which is an indication of the outbreak control. The SIR models for the countries in this group showed that they passed the expected 99% end of pandemic dates. Group B, however, exhibited a continuous increase of the total COVID-19 new cases, that best suited an exponential growth model with r² > 0.97, which meant that the outbreak is still uncontrolled. The SIR models for the countries in this group showed that they are still relatively far away from reaching the expected 97% end of pandemic dates. The maximum death percentage varied from 3.3% (India) to 7.2% with USA recording the highest death percentage, which is virtually equal to the maximum death percentage of the world (7.3%). The power of the exponential model determines the severity of the country's trajectory that ranged from 11 to 19 with the USA and Brazil having the highest values. The maximum impact of this COVID-19 pandemic occurred during the uncontrolled stage (2), which mainly depended on the deceptive stage (1). Further, some novel potential containment strategies are discussed. Results from both models showed that the Group A countries contained the outbreak, whereas the Group B countries still have not reached this stage yet. Early measures and containment strategies are imperative in suppressing the spread of COVID-19.

Household spraying in cholera outbreaks: Insights from three exploratory, mixed-methods field effectiveness evaluations

Household spraying is a commonly implemented, yet an under-researched, cholera response intervention where a response team sprays surfaces in cholera patients' houses with chlorine. We conducted mixed-methods evaluations of three household spraying programs in the Democratic Republic of Congo and Haiti, including 18 key informant interviews, 14 household surveys and observations, and 418 surface samples collected before spraying, 30 minutes and 24 hours after spraying. The surfaces consistently most contaminated with Vibrio cholerae were food preparation areas, near the patient's bed and the latrine. Effectiveness varied between programs, with statistically significant reductions in V. cholerae concentrations 30 minutes after spraying in two programs. Surface contamination after 24 hours was variable between households and programs. Program challenges included difficulty locating households, transportation and funding limitations, and reaching households quickly after case presentation (disinfection occurred 2-6 days after reported cholera onset). Program advantages included the concurrent deployment of hygiene promotion activities. Further research is indicated on perception, recontamination, cost-effectiveness, viable but nonculturable V. cholerae, and epidemiological coverage. We recommend that, if spraying is implemented, spraying agents should: disinfect surfaces systematically until wet using 0.2/2.0% chlorine solution, including kitchen spaces, patients' beds, and latrines; arrive at households quickly; and, concurrently deploy hygiene promotion activities.

Estimating the nationwide transmission risk of measles in US schools and impacts of vaccination and supplemental infection control strategies

BACKGROUND

The spread of airborne infectious diseases such as measles is a critical public health concern. The U.S. was certified measles-free in 2000, but the number of measles cases has increased in recent years breaking the record of the nationwide annual number of cases since 1992. Although the characteristics of schools have made them one of the most vulnerable environments during infection outbreaks, the transmission risk of measles among students is not completely understood. We aimed to evaluate how three factors influence measles transmission in schools: personal (vaccination), social (compartmentalizing), and building systems (ventilation, purification, and filtration).

METHODS

We used a combination of a newly developed multi-zone transient Wells-Riley approach, a nationwide representative School Building Archetype (SBA) model, and a Monte-Carlo simulation to estimate measles risk among U.S. students. We compared our risk results with the range of reported transmission rates of measles in school outbreaks to validate the risk model. We also investigated the effectiveness of vaccination and ten supplemental infection control scenarios for reducing the risk of measles transmission among students.

RESULTS

Our best nationwide estimate of measles transmission risk in U.S. schools were 3.5 and 32% among all (both unvaccinated and immunized) and unvaccinated students, respectively. The results showed the transmission risk of measles among unvaccinated students is > 70 times higher than properly immunized ones. We also demonstrated that the transmission risk of measles in primary schools (assuming teacher self-contained classrooms) is less than secondary schools (assuming departmentalized systems). For building-level interventions, schools with ductless-with-air-filter and ductless-without-air-filter systems have the lowest and highest transmission risks of measles, respectively. Finally, our simulation showed that infection control strategies could cut the average number of infected cases among all students in half when a combination of advanced air filtration, ventilation, and purification was adopted in the modeled schools.

CONCLUSIONS

Our results highlight the primary importance of vaccination for reducing the risk of measles transmission among students. Yet, additional and significant risk reduction can be achieved through compartmentalizing students and enhancing building ventilation and filtration systems.

Are Quaternary Ammonium Compounds, the Workhorse Disinfectants, Effective against Severe Acute Respiratory Syndrome-Coronavirus-2?

A novel virus named Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) emerged from Wuhan, China in late 2019. Since then, the virus has quickly spread worldwide, leading the World Health Organization to declare it as a pandemic; by the end of April 2020, the number of cases exceeded 3 million. Due to the high infectivity rate, SARS-CoV-2 is difficult to contain, making disinfectant protocols vital, especially for essential, highly trafficked areas such as hospitals, grocery stores, and delivery centers. According to the Centers for Disease Control and Prevention, best practices to slow the spread rely on good hand hygiene, including proper handwashing practices as well as the use of alcohol-based hand sanitizers. However, they provide warning against sanitizing products containing benzalkonium chloride (BAC), which has sparked concern in both the scientific community as well as the general public as BAC, a common quaternary ammonium compound (QAC), is ubiquitous in soaps and cleaning wipes as well as hospital sanitation kits. This viewpoint aims to highlight the outdated and incongruous data in the evaluation of BAC against the family of known coronaviruses and points to the need for further evaluation of the efficacy of QACs against coronaviruses.

Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings-Personal Protective and Environmental Measures

There were 3 influenza pandemics in the 20th century, and there has been 1 so far in the 21st century. Local, national, and international health authorities regularly update their plans for mitigating the next influenza pandemic in light of the latest available evidence on the effectiveness of various control measures in reducing transmission. Here, we review the evidence base on the effectiveness of nonpharmaceutical personal protective measures and environmental hygiene measures in nonhealthcare settings and discuss their potential inclusion in pandemic plans. Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza. We similarly found limited evidence on the effectiveness of improved hygiene and environmental cleaning. We identified several major knowledge gaps requiring further research, most fundamentally an improved characterization of the modes of person-to-person transmission.

Metagenomic Analysis of Regularly Microwave-Treated and Untreated Domestic Kitchen Sponges

Kitchen sponges massively absorb and spread microorganisms, leading to contamination of kitchen appliances, surfaces, and food. Microwaving as an effective and widespread technique can rapidly reduce the microbial load of kitchen sponges. However, long-term effects of such treatments are largely unknown. Notably, it has been speculated that regularly applied domestic cleaning and disinfection may select for microbial communities with a higher pathogenic potential and/or malodorous properties. In this study, we distributed newly purchased polyurethane kitchen sponges to 20 participants, with the instruction to use them under normal household conditions for four weeks. Ten of the participants sanitized their sponges regularly by a standardized microwaving protocol, while the remaining ten sponges remained untreated. Metagenomic sequence data evaluation indicated that, in addition to bacteria, viruses, eukaryotes, and archaea were also part of the kitchen sponge microbiome. Comparisons of sanitized and untreated kitchen sponges indicated a trend towards a reduced structural microbial diversity while functional diversity increased. Microwave sanitization appeared to alter composition and metabolic properties of the microbial communities. Follow-up studies will have to show whether these changes are more positive or negative in terms of domestic hygiene, human health, and well-being.

Superhemophobic and Antivirofouling Coating for Mechanically Durable and Wash-Stable Medical Textiles

Medical textiles have a need for repellency to body fluids such as blood, urine, or sweat that may contain infectious vectors that contaminate surfaces and spread to other individuals. Similarly, viral repellency has yet to be demonstrated and long-term mechanical durability is a major challenge. In this work, we demonstrate a simple, durable, and scalable coating on nonwoven polypropylene textile that is both superhemophobic and antivirofouling. The treatment consists of polytetrafluoroethylene (PTFE) nanoparticles in a solvent thermally sintered to polypropylene (PP) microfibers, which creates a robust, low-surface-energy, multilayer, and multilength scale rough surface. The treated textiles demonstrate a static contact angle of 158.3 ± 2.6° and hysteresis of 4.7 ± 1.7° for fetal bovine serum and reduce serum protein adhesion by 89.7 ± 7.3% (0.99 log). The coated textiles reduce the attachment of adenovirus type 4 and 7a virions by 99.2 ± 0.2% and 97.6 ± 0.1% (2.10 and 1.62 log), respectively, compared to noncoated controls. The treated textiles provide these repellencies by maintaining a Cassie-Baxter state of wetting where the surface area in contact with liquids is reduced by an estimated 350 times (2.54 log) compared to control textiles. Moreover, the treated textiles exhibit unprecedented mechanical durability, maintaining their liquid, protein, and viral repellency after extensive and harsh abrasion and washing. The multilayer, multilength scale roughness provides for mechanical durability through self-similarity, and the samples have high-pressure stability with a breakthrough pressure of about 255 kPa. These properties highlight the potential of durable, repellent coatings for medical gowning, scrubs, or other hygiene textile applications.

Ozone efficacy for the control of airborne viruses: Bacteriophage and norovirus models

This study was designed to test the efficacy of an air treatment using ozone and relative humidity (RH) for the inactivation of airborne viruses. Four phages (φX174, PR772, MS2 and φ6) and one eukaryotic virus (murine norovirus MNV-1) were exposed to low ozone concentrations (1.23 ppm for phages and 0.23 ppm for MNV-1) and various levels of RH for 10 to 70 minutes. The inactivation of these viruses was then assessed to determine which of the tested conditions provided the greatest reduction in virus infectivity. An inactivation of at least two orders of magnitude for φX174, MS2 and MNV-1 was achieved with an ozone exposure of 40 minutes at 85% RH. For PR772 and φ6, exposure to the reference condition at 20% RH for 10 minutes yielded the same results. These findings suggest that ozone used at a low concentration is a powerful disinfectant for airborne viruses when combined with a high RH. Air treatment could therefore be implemented inside hospital rooms ventilated naturally.

Effect of Bacteria and Bacterial Constituents on Recovery and Resistance of Tulane Virus

Noroviruses encounter numerous and diverse bacterial populations in the host and environment, but the impact of bacteria on norovirus transmission, infection, detection, and inactivation are not well understood. Tulane virus (TV), a human norovirus surrogate, was exposed to viable bacteria, bacterial metabolic products, and bacterial cell constituents and was evaluated for impact on viral recovery, propagation, and inactivation resistance, respectively. TV was incubated with common soil, intestinal, skin, and phyllosphere bacteria, and unbound viruses were recovered by centrifugation and filtration. TV recovery from various bacterial suspensions was not impeded, which suggests a lack of direct, stable binding between viruses and bacteria. The cell-free supernatant (CFS) of Bifidobacterium bifidum 35914, a bacterium that produces glycan-modifying enzymes, was evaluated for effect on the propagation of TV in LLC-MK2 cells. CFS did not limit TV propagation relative to TV absent of CFS. The impact of Escherichia coli O111:B4 lipopolysaccharide (LPS) and Bacillus subtilis peptidoglycan (PEP) on TV thermal and chlorine inactivation resistance was evaluated. PEP increased TV thermal and chlorine inactivation resistance compared with control TV in phosphate-buffered saline (PBS). TV suspended in PBS and LPS was reduced by more than 3.7 log at 60°C, whereas in PEP, TV reduction was approximately 2 log. Chlorine treatment (200 ppm) rendered TV undetectable (>3-log reduction) in PBS and LPS; however, TV was still detected in PEP, reduced by 2.9 log. Virus inactivation studies and food processing practices should account for potential impact of bacteria on viral resistance.

Test methods for surface disinfection: comparison of the Wiperator ASTM standard E2967-15 and the 4-field test EN 16615

Aim: Two test methods for surface disinfection (phase 2, step 2) – the Wiperator method (ASTM standard E2967-15) and the 4-field test (EN 16615) – were compared using a disinfectant solution based on quaternary ammonium compounds and a ready-to-use alcohol-based wipe. As test organisms, Staphylococcusaureus and Pseudomonasaeruginosa were used.

Results: While the 4-field test is a manual method and better reflects the process in practice, with the Wiperator, the wiping process is better controlled because it is an automated procedure. A comparison of the effects of both methods on the target log₁₀-reduction of S. aureus and P. aeruginosa indicates a statistically significant difference between the two test methods (Mann-Whitney U-Test. S. aureus: 0 (U_min)<4 (U_crit); n₁=8, n₂=8, p=0.001; 2-sided. P. aeruginosa: 24 (U_min)<26 (U_crit); n₁=11, n₂=10, p=0.025, 2-sided). In addition, the results indicate that the wipe used has a major influence on the success of the disinfection process.

Discussion: Both methods are suitable for efficacy studies of surface disinfectants, yet they differ in some aspects. Additionally our data indicate a statistically significant difference between the two test methods.

Conclusion: Efficiency testing of surface disinfection is a complex process that depends on many different parameters. Since the 4-field test better reflects the practice, it makes sense to stick to this test procedure, taking into account that the EN 16615 was approved by CEN TC 216 in 2015 after method validation ring trials.

From one species to another: A review on the interaction between chemistry and microbiology in relation to cleaning in the built environment

Since the advent of soap, personal hygiene practices have revolved around removal, sterilization, and disinfection-both of visible soil and microscopic organisms-for a myriad of cultural, aesthetic, or health-related reasons. Cleaning methods and products vary widely in their recommended use, effectiveness, risk to users or building occupants, environmental sustainability, and ecological impact. Advancements in science and technology have facilitated in-depth analyses of the indoor microbiome, and studies in this field suggest that the traditional "scorched-earth cleaning" mentality-that surfaces must be completely sterilized and prevent microbial establishment-may contribute to long-term human health consequences. Moreover, the materials, products, activities, and microbial communities indoors all contribute to, or remove, chemical species to the indoor environment. This review examines the effects of cleaning with respect to the interaction of chemistry, indoor microbiology, and human health.

Survival and inactivation of Salmonella enterica serovar Typhimurium on food contact surfaces during log, stationary and long-term stationary phases

One of the most important transmission routes of foodborne pathogens is through contaminated food contact surfaces. In this study, we investigated the survival and inactivation of Salmonella enterica serovar Typhimurium on frequently used food contact surfaces in household settings, including plastic cutting board (CB), formica laminate (LA), and stainless steel (SS) surfaces. S. Typhimurium at log (6 h), stationary (24 h), or long-term stationary (LTS) (14 days) phases were evaluated. Results showed that, at medium and high microbial loads, LTS phase cells had significantly higher survivor population compared to log and stationary phase cells at 24 h after inoculation (p < 0.05). Disinfection study showed that LTS phase cells were very resilient to sodium hypochlorite when the initial microbial load was high with disinfection efficacy ranging from 26 to 35%. Scanning electron microscopy of these surfaces at 24 h after inoculation with a high microbial load revealed an early biofilm structure.

Background Information: Isolation Routines

The isolation of patients with suspected or documented infections—to not spread to others—has been discussed for hundreds of years. Guidelines are many, methods are different, attitudes show vide variations, routines and procedures are still changing, regulations by law may be absent, and some healthcare professionals may be afraid of adverse outcomes of isolation [1–44]. Microbes that are spread in the environment, on the hands and equipment are invisible. The invisible agent does not call on attention before the infection; clinical disease, hospital infection or nosocomial infection is a factum that can be registered [23, 28, 29, 35–37]. How to stop the transmission is often “to believe and not believe” in infection control.

Antibacterial effects of nano-imprinted moth-eye film in practical settings

BACKGROUND

Recent studies report that surfaces displaying micrometer- or nanometer-sized undulating structures exhibit antibacterial effects. In previous work, we described the use of an advanced nanofabrication technique to generate an artificial biomimetic Moth-eye film by coating a polyethylene terephthalate (PET) film with nanoscale moth-eye protrusions made from a hydrophilic resin. This moth-eye film exhibited enhanced antibacterial effects in in vitro experiments. The aim of the present study was to verify the antibacterial efficacy of the Moth-eye film in practical environments.

MATERIALS AND METHODS

The antibacterial effects of three types of film (Moth-eye film, Flat film, and PET film) were compared. Sample films were pasted onto hand washing basins at the testing locations. After several hours, bacteria were collected from the surface of the sample films with one of three kinds of culture media stamper (to permit identification of bacterial species). The stampers were incubated for 48 hours at 35°C, and the numbers of colonies were counted.

RESULTS AND DISCUSSION

The number of common bacteria including E. coli and S. aureus obtained from the Moth-eye film was significantly lower than those from the PET film (p<0.05) and Flat film at 1 hour (p<0.05). This study found that the Moth-eye film showed a long-term (6h) antibacterial effect and the Moth-eye structure (PET coated with nanoscale cone-shaped pillars) demonstrated a physical antibacterial effect from earlier time points. Therefore, the Moth-eye film appears to have potential general-purpose applications in practical environments.

Modeling Surface Disinfection Needs To Meet Microbial Risk Reduction Targets

Nosocomial viral infections are an important cause of health care-acquired infections where fomites have a role in transmission. Using stochastic modeling to quantify the effects of surface disinfection practices on nosocomial pathogen exposures and infection risk can inform cleaning practices. The purpose of this study was to predict the effect of surface disinfection on viral infection risks and to determine needed viral reductions to achieve risk targets. Rotavirus, rhinovirus, and influenza A virus infection risks for two cases were modeled. Case 1 utilized a single fomite contact approach, while case 2 assumed 6 h of contact activities. A 94.1% viral reduction on surfaces and hands was measured following a single cleaning round using an Environmental Protection Agency (EPA)-registered disinfectant in an urgent care facility. This value was used to model the effect of a surface disinfection intervention on infection risk. Risk reductions for other surface-cleaning efficacies were also simulated. Surface reductions required to achieve risk probability targets were estimated. Under case 1 conditions, a 94.1% reduction in virus surface concentration reduced infection risks by 94.1%. Under case 2 conditions, a 94.1% reduction on surfaces resulted in median viral infection risks being reduced by 92.96 to 94.1% and an influenza A virus infection risk below one in a million. Surface concentration in the equations was highly correlated with dose and infection risk outputs. For rotavirus and rhinovirus, a >99.99% viral surface reduction would be needed to achieve a one-in-a-million risk target. This study quantifies reductions of infection risk relative to surface disinfectant use and demonstrates that risk targets for low-infectious-dose organisms may be more challenging to achieve.IMPORTANCE It is known that the use of EPA-registered surface disinfectant sprays can reduce infection risk if used according to the manufacturer's instructions. However, there are currently no standards for health care environments related to contamination levels on surfaces. The significance of this research is in quantifying needed reductions to meet various risk targets using realistic viral concentrations on surfaces for health care environments. This research informs the design of cleaning protocols by demonstrating that multiple applications may be needed to reduce risk and by highlighting a need for more models exploring the relationship among microbial contamination of surfaces, patient and health care worker behaviors, and infection risks.

Enhanced Removal of Norovirus Surrogates, Murine Norovirus and Tulane Virus, from Aqueous Systems by Zero-Valent Iron

Viral contamination can compromise the safety of water utilized for direct consumption, produce irrigation, and postharvest washing of produce. Zero-valent iron (ZVI) is used commercially for chemical remediation of water and has been demonstrated to remove some biological contaminants from water in laboratory and field studies. This study investigated the efficacy of ZVI to remove human norovirus surrogates, Tulane virus (TV) and murine norovirus (MNV), from water and to characterize the reversibility and nature of viral association with ZVI. Genomic material of TV and MNV recovered from the effluent of inoculated water treatment columns containing a 1:1 mixture of ZVI and sand was 2 and 3 log, respectively, less than that recovered from the effluent of treatment columns containing only sand. Elution buffers (citrate buffers, pH 4 and 7, and virus elution buffer, pH 9.5, with and without added 1 M NaCl) did not increase recovery of infectious TV and MNV from ZVI as compared with elution with water alone. TV-inoculated lettuce washed with water in the presence of ZVI yielded 1.5 to 2 log fewer infectious TV from washwater as compared with lettuce washed with water alone or in the presence of sand. These data demonstrate the enhanced removal of human norovirus surrogates, TV and MNV, from water by ZVI and provide indications that unrecovered viruses are not readily disassociated from ZVI by buffers of various pH and ionic strength. These findings warrant further investigation into larger-scale simulations of water remediation of viral contaminants for potential application in the treatment of water used for drinking, irrigation, and food processing.

Prevalence of Human Parainfluenza Viruses and Noroviruses Genomes on Office Fomites

The aim of this study was to evaluate the potential role of office fomites in respiratory (human parainfluenza virus 1-HPIV1, human parainfluenza virus 3-HPIV3) and enteric (norovirus GI-NoV GI, norovirus GII-NoV GII) viruses transmission by assessing the occurrence of these viruses on surfaces in office buildings. Between 2016 and 2017, a total of 130 surfaces from open-space and non-open-space rooms in office buildings located in one city were evaluated for HPIV1, HPIV3, NoV GI, and NoV GII viral RNA presence. Detection of viruses was performed by RT-qPCR method. Study revealed 27 positive samples, among them 59.3% were HPIV3-positive, 25.9% HPIV1-positive, and 14.8% NoV GII-positive. All tested surfaces were NoV GI-negative. Statistical analysis of obtained data showed that the surfaces of office equipment including computer keyboards and mice, telephones, and desktops were significantly more contaminated with respiratory viruses than the surfaces of building equipment elements such as door handles, light switches, or ventilation tracts (χ 2 p = 0.006; Fisher's Exact p = 0.004). All examined surfaces were significantly more contaminated with HPIVs than NoVs (χ 2 p = 0.002; Fisher's Exact p = 0.003). Office fomites in open-space rooms were more often contaminated with HPIVs than with NoVs (χ 2 p = 0.016; Fisher's Exact p = 0.013). The highest average concentration of HPIVs RNA copies was observed on telephones (1.66 × 102 copies/100 cm2), while NoVs on the light switches (1.40 × 102 copies/100 cm2). However, the Kruskal-Wallis test did not show statistically significant differences in concentration levels of viral RNA copies on surfaces between the all tested samples. This study unequivocally showed that individuals in office environment may have contact with both respiratory and enteric viral particles present on frequently touched surfaces.

Bayesian evidence and epidemiological implications of environmental contamination from acute respiratory infection in long-term care facilities

Skilled nursing home facilities (SNFs) house a vulnerable population frequently exposed to respiratory pathogens. Our study aims to gain a better understanding of the transmission of nursing home-acquired viral respiratory infections in non-epidemic settings. Symptomatic surveillance was performed in three SNFs for residents exhibiting acute respiratory symptoms. Environmental surveillance of five high-touch areas was performed to assess possible transmission. All resident and environmental samples were screened using a commercial multiplex polymerase chain reaction platform. Bayesian methods were used to evaluate environmental contamination. Among nursing home residents with respiratory symptoms, 19% had a detectable viral pathogen (parainfluenza-3, rhinovirus/enterovirus, RSV, or influenza B). Environmental contamination was found in 20% of total room surface swabs of symptomatic residents. Environmental and resident results were all concordant. Target period prevalence among symptomatic residents ranged from 5.5 to 13.3% depending on target. Bayesian analysis quantifies the probability of environmental shedding due to parainfluenza-3 as 92.4% (95% CI: 86.8–95.8%) and due to rhinovirus/enterovirus as 65.6% (95% CI: 57.9–72.5%). Our findings confirm that non-epidemic viral infections are common among SNF residents exhibiting acute respiratory symptoms and that environmental contamination may facilitate further spread with considerable epidemiological implications. Findings further emphasise the importance of environmental infection control for viral respiratory pathogens in long-term care facilities.