Investigation of the Antibacterial Properties of Silver-Doped Amorphous Carbon Coatings Produced by Low Pressure Magnetron Assisted Acetylene Discharges

Hospital-acquired infections are responsible for a significant part of morbidity and mortality. Among the possible modes of transmission, this study focuses on environmental surfaces by developing innovative antibacterial coatings that can be applied on interior fittings in hospitals. This work aims to optimize a coating made of an amorphous carbon matrix doped with silver (a-C:H:Ag) produced by a hybrid PVD/PECVD process and to evaluate its antibacterial activity. We present a coating characterization (chemical composition and morphology) as well as its stability in an ageing process and after multiple exposures to bacteria. The antibacterial activity of the coatings is demonstrated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria through several bioassays. Moreover, the data suggest a crucial role of silver diffusion towards the surface and nanoparticle formation to explain the very promising anti-bacterial activities reported in this work.

Inactivation of SARS-CoV-2 and influenza A virus by spraying hypochlorous acid solution and hydrogen peroxide solution in the form of Dry Fog

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is transmitted by droplet and contact infection. SARS-CoV-2 that adheres to environmental surfaces remains infectious for several days. We herein attempted to inactivate SARS-CoV-2 and influenza A virus adhering to an environmental surface by spraying aerosolized hypochlorous acid solution and hydrogen peroxide solution in the form of Dry Fog (fog that does not wet objects even if touched). SARS-CoV-2 and influenza virus were dried on plastic plates and placed into a test chamber for inactivation by the Dry Fog spraying of disinfectants. The results obtained showed that Dry Fog spraying inactivated SARS-CoV-2 and influenza A virus in time- and exposed disinfectant amount-dependent manners. SARS-CoV-2 was more resistant to the virucidal effects of aerosolized hypochlorous acid solution and hydrogen peroxide solution than influenza A virus; therefore, higher concentrations of spray solutions were required to inactivate SARS-CoV-2 than influenza A virus. The present results provide important information for the development of a strategy that inactivates SARS-CoV-2 and influenza A virus on environmental surfaces by spatial spraying.

Antimicrobial Photodynamic Coatings Reduce the Microbial Burden on Environmental Surfaces in Public Transportation - a Field Study in Buses

Millions of people use public transportation daily worldwide and frequently touch surfaces, thereby producing a reservoir of microorganisms on surfaces increasing the risk of transmission. Constant occupation makes sufficient cleaning difficult to achieve. Thus, an autonomous, perma-nent antimicrobial coating (AMC) could keep down the microbial burden on such surfaces. A photodynamic AMC was applied to frequently touched surfaces in buses. The microbial burden (colony forming units, cfu) was determined weekly and compared to equivalent surfaces in buses without AMC (references). The microbial burden ranged from 0 – 209 cfu/cm² on references and from 0 – 54 cfu/cm² on AMC. The means were 13.4 ± 29.6 cfu/cm² on references and 4.5 ± 8.4 cfu/cm² on AMC (p<0.001). The difference of microbial burden on AMC and references was al-most constant throughout the study. Considering a hygiene benchmark of 5 cfu/cm², the data yield an absolute risk reduction of 22.6 % and a relative risk reduction of 50.7 %. In conclusion, photo-dynamic AMC kept down the microbial burden, reducing the risk of transmission of microor-ganisms. AMC permanently and autonomously contributes to hygienic conditions on surfaces in public transportation. Photodynamic AMC therefore are suitable for reducing the microbial load and closing hygiene gaps in public transportation.

380. Environmental Contamination with SARS-CoV-2 in Nursing Homes

Background The COVID-19 pandemic has disproportionately affected nursing home (NH) patients, accounting for 5% of all cases and 32% of all COVID-19 deaths nationwide. Little is known about the frequency and persistence of SARS-CoV-2 environmental contamination in NHs. We characterize SARS-CoV-2 contamination in the rooms of COVID-19 patients and common areas in and around COVID-19 units. Methods A prospective cohort study was conducted at four NHs in Michigan between October 2020 and January 2021. Clinical research personnel obtained swab specimens from high-touch room surfaces of COVID-19 infected patients, up to three times per patient. Weekly swab specimens from six high-touch surfaces in common areas were also obtained. Demographic and clinical data were collected from patient clinical records. Our primary outcome of interest was the probability of SARS-CoV-2 detection from specific environmental surfaces in COVID-19 patient rooms. Results One hundred four patients with COVID-19 were enrolled and followed for 241 visits. Patient characteristics included: 61.5% over the age of 80; 67.3% female; 89.4% non-Hispanic white; 50.1% short-stay. The study population had significant disabilities in activities of daily living (ADL; 81.7% dependent in four or more ADLs) and comorbidities including dementia (55.8%), diabetes (40.4%) and heart failure (32.7) (Table 1). Over the 3-month study period, 2087 swab specimens were collected (1896 COVID-19 patient room surfaces, 191 common area swabs). Figure 1 shows contamination rates at sites proximate and distant to the patient bed. SARS-CoV-2 positivity was 28.4% (538/1896 swabs) on patient room surfaces and 3.7% (7/191 swabs) on common area surfaces. Over the course of follow-up, 89.4% (93/104) of patients had SARS-CoV-2 contamination in their room at least once (Figure 2). Environmental contamination detected on enrollment correlated with contamination of the same site during follow-up. Functional independence increased the odds of proximate contamination. Table 1. Clinical and Demographic Characteristics of the Study Population Including Short- and Long-stay Patients Figure 1. Contamination of Environmental Surfaces Relative to Distance from Patient Bed Figure 2. SARS-CoV-2 on Swab Specimens Collected – Patient-level, Visit-level, and Swab-level Conclusion We conclude that environmental contamination of surfaces in the rooms of COVID-19 patients is nearly universal and persistent. Patients with greater independence are more likely than fully dependent patients to contaminate their immediate environment. Disclosures All Authors: No reported disclosures

782. A Comparison of Four Different Sampling Methods Used to Recover Contamination from Environmental Surfaces

Background We hypothesized that sampling tools with the largest surface area would be the most efficient at recovering bacteria. To test this hypothesis, we evaluated four different sampling methods to see which was most effective at recovering bacteria from common environmental surfaces. Methods At UNC Medical Center, a 951 bed academic facility, we tested four collection methods: swabs, RODAC (replicate organism detection and counting) plates, Sponge Sticks with manual extraction and Sponge Sticks using extraction with the Seward Stomacher. Laminate and stainless steel surfaces (100 cm²) were used for testing. Known quantities of Staphylococcus aureus (SA) and Klebsiella pneumoniae (KP) were applied across the test surfaces, then allowed to dry prior to sampling. Swab samples were collected by rubbing a moistened swab over the test surface, followed by a dry swab. Both swab tips were broken into a tube of saline and mixed. An aliquot of each was inoculated to agar plates. Each RODAC agar plate was pressed onto a test surface. Sponge Stick samples were collected by rubbing a pre-moistened sponge over the test surface. Each sponge head was ejected into a bag containing saline. For manual agitation, each bag was kneaded by hand for 1 minute. For Stomacher method, bags were processed for 1 minute. The contents of each bag were poured into tubes, then centrifuged. The supernatant was removed from each tube. An aliquot of each was inoculated to agar plates. Plates were incubated at 35°C, then colonies were counted for each plate. Results Comparative recovery rates across surfaces, organism types and sampling methods are shown in the table. Conclusion Organism type, not sampling method, appeared to the most important factor in bacterial recovery. Recovery of SA was significantly higher than KP, likely because it was able to better withstand manipulation and the physical stress of drying on test surfaces. The sampling tool appeared to have the second largest impact. RODAC yielded the highest recovery, followed by swabs, then sponges. Knowing the variable recovery based on method, surface and organism is important for meaningful interpretation of environmental surveillance conducted during outbreak investigations or quality assurance monitoring. Disclosures William Rutala, MS, MPH, PhD, PDI (Professional Disposibles International) (Consultant) David J. Weber, MD, MPH, PDI (Consultant)

Evidence Map and Systematic Review of Disinfection Efficacy on Environmental Surfaces in Healthcare Facilities

Healthcare-associated infections (HAIs) contribute to patient morbidity and mortality with an estimated 1.7 million infections and 99,000 deaths costing USD $28–34 billion annually in the United States alone. There is little understanding as to if current environmental surface disinfection practices reduce pathogen load, and subsequently HAIs, in critical care settings. This evidence map includes a systematic review on the efficacy of disinfecting environmental surfaces in healthcare facilities. We screened 17,064 abstracts, 635 full texts, and included 181 articles for data extraction and study quality assessment. We reviewed ten disinfectant types and compared disinfectants with respect to study design, outcome organism, and fourteen indictors of study quality. We found important areas for improvement and gaps in the research related to study design, implementation, and analysis. Implementation of disinfection, a determinant of disinfection outcomes, was not measured in most studies and few studies assessed fungi or viruses. Assessing and comparing disinfection efficacy was impeded by study heterogeneity; however, we catalogued the outcomes and results for each disinfection type. We concluded that guidelines for disinfectant use are primarily based on laboratory data rather than a systematic review of in situ disinfection efficacy. It is critically important for practitioners and researchers to consider system-level efficacy and not just the efficacy of the disinfectant.

Discrimination and isolation of the virus from free RNA fragments for the highly sensitive measurement of SARS-CoV-2 abundance on surfaces using a graphene oxide nano surface

It is highly important to sensitively measure the abundance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on various surfaces. Here, we present a nucleic acid-based detection method consisting of a new sample preparation protocol that isolates only viruses, not the free RNA fragments already present on the surfaces of indoor human-inhabited environments, using a graphene oxide-coated microbead filter. Wet wipes (100 cm2), not cotton swabs, were used to collect viruses from environmental surfaces with large areas, and viruses were concentrated and separated with a graphene oxide-coated microbead filter. Viral RNA from virus was recovered 88.10 ± 8.03% from the surface and free RNA fragment was removed by 99.75 ± 0.19% from the final eluted solution. When we tested the developed method under laboratory conditions, a 10-fold higher viral detection sensitivity (Detection limit: 1 pfu/100 cm2) than the current commercial protocol was observed. Using our new sample preparation protocol, we also confirmed that the virus was effectively removed from surfaces after chemical disinfection; we were unable to measure the disinfection efficiency using the current commercial protocol because it cannot distinguish between viral RNA and free RNA fragments. Finally, we investigated the presence of SARS-CoV-2 and bacteria in 12 individual negative pressure wards in which patients with SARS-CoV-2 infection had been hospitalized. Bacteria (based on 16 S DNA) were found in all samples collected from patient rooms; however, SARS-CoV-2 was mainly detected in rooms shared by two patients.

Efficiency of coronavirus inactivation on environmental surfaces: A comparison study of two available disinfectants

Background: There are many coronaviruses of significant medical and veterinary concern, all of which are the result of spillover from another species. Disinfection of healthcare and veterinary environments is an important factor in limiting the transmission of coronaviruses. Disinfection agents for coronaviruses use bleach, quaternary compounds, hydrogen peroxide, and sodium hydroxide. Product labels list contact times that range from 10-30 minutes for total inactivation. Decon7 is a combination disinfectant that is currently used in the food and agriculture, medical facilities, and other industries. While Decon7 has been shown to inactivate a variety of pathogens and disrupt biofilms, its effectiveness and rate of coronavirus inactivation has not been evaluated.Objective: This project sought to evaluate Decon7’s effectiveness and rate of coronavirus inactivation.Methods: This study evaluated the disinfection efficacy of Decon7 (diluted at 1:4) and bleach (diluted at 1:10) after 3 coronaviruses (SARS-CoV-2, HCoV OC43, and HCoV NL63) were inoculated onto up to sixteen environmental surface materials.Results: A 1:4 dilution of Decon7 inactivated all coronaviruses on all surfaces with 1 minute contact time. A 1:10 dilution of bleach was not effective in inactivating coronaviruses with a contact time of 1 minute on all surfaces.Conclusions: New technologies and chemistries may offer more efficient inactivation of pathogens on environmental surfaces. These disinfection methods and materials, which require less than 10 minutes contact time, may improve the efficacy of cleaning and disinfecting surfaces in the built environment.