Method validation for the recovery of the porcine respiratory and reproductive syndrome virus, a potential SARS-CoV-2 surrogate, from stainless steel.

Virus survival on fomites may represent a vehicle for transmission to humans. This study was conducted to optimize and validate a recovery method for the porcine respiratory and reproductive syndrome virus (PRRSV), a potential SARS-CoV-2 surrogate, from stainless steel. Coupons (1.5 × 1.5 cm) inoculated with ca. 7 logs TCID50 of PRRSV were dried for 15 min at room temperature, followed by incubation at 4°C and 35% relative humidity. After 1 h and 24 h, the coupons were processed by four different methods: vortex in DMEM media, vortex in DMEM media with beads, vortex in elution buffer, and shake in elution buffer. The rinsates were processed for titration using the TCID50 method in the MARC-145 cell line. All four methods were equally effective to recover the virus from the soiled SS surfaces (> 79% recovery). The amount of infectious virus recovered after 24 h was similar (P > 0.05) to that recovered after 1 h, indicating that the virus was stable at 4°C for up to 24 h. Using an elution buffer followed by shaking was the least labor-intensive and most economical method. Therefore, this method will be used for future experiments on PRRSV survival and transfer from food-contact surfaces.

Survival of human coronavirus 229E at different temperatures on various food-contact surfaces and food and under simulated digestive conditions.

The COVID-19 pandemic caused by SARS-CoV-2 has had a major impact on human health and the global economy. Various transmission possibilities of SARS-CoV-2 have been proposed, such as the surface of food in the cold chain and food packaging, as well as the fecal-oral route, although person-to-person contact via droplets and aerosols has been confirmed as the main route of transmission. This study evaluated the survivability of HCoV-229E, a SARS-CoV-2 surrogate, in suspension, on food-contact surfaces and on food at various temperatures, and in simulated digestive fluids by TCID50 assay. In suspension, HCoV-229E survived after 5 days at 20 °C with a 3.69 log reduction, after 28 days at 4 °C with a 3.07 log reduction, and after 12 weeks at -20 °C with a 1.18 log reduction. On food-contact surfaces, HCoV-229E was not detected on day 3 on stainless steel (SS), plastic (LDPE), and silicone rubber (SR) at 20 °C with a 3.28, 3.24 and 3.28 log reduction, respectively, and survived after 28 days on SS and LDPE at 4 °C with a 3.13 and 2.88 log reduction, respectively, and survived after 12 weeks on SS, LDPE, and SR at -20 °C with a 1.92, 1.32 and 1.99 log reduction, respectively. On food, HCoV-229E was not detected on day 3 on lettuce and day 4 on chicken breast and salmon at 20 °C with a 3.61, 3.26 and 3.08 log reduction, respectively, and on day 14 on lettuce and day 21 on chicken breast and salmon at 4 °C with a 3.88, 3.44 and 3.56 log reduction, respectively. The virus remained viable for 12 weeks in all foods at -20 °C with 2-2.47 log reduction. In addition, in simulated digestive fluid experiments, HCoV-229E was relatively resistant in simulated salivary fluid (SSF; pH 7, 5), fed state simulated gastric fluid (FeSSGF; pH 3, 5, 7), and fasted state simulated intestinal fluid (FaSSIF; pH 7). However, the virus was less tolerant in fasted state simulated gastric fluid (FaSSGF; pH 1.6) and fed state simulated intestinal fluid (FeSSIF; pH 5). Therefore, this study suggested that HCoV-229E remained infectious on various food-contact surfaces and foods; in particular, it survived longer at lower temperatures and survived depending on the pH of the simulated digestive fluid.

Comparative Experimental Investigation of Biodegradable Antimicrobial Polymer-Based Composite Produced by 3D Printing Technology Enriched with Metallic Particles.

Due to the prevailing existence of the COVID-19 pandemic, novel and practical strategies to combat pathogens are on the rise worldwide. It is estimated that, globally, around 10% of hospital patients will acquire at least one healthcare-associated infection. One of the novel strategies that has been developed is incorporating metallic particles into polymeric materials that neutralize infectious agents. Considering the broad-spectrum antimicrobial potency of some materials, the incorporation of metallic particles into the intended hybrid composite material could inherently add significant value to the final product. Therefore, this research aimed to investigate an antimicrobial polymeric PLA-based composite material enhanced with different microparticles (copper, aluminum, stainless steel, and bronze) for the antimicrobial properties of the hybrid composite. The prepared composite material samples produced with fused filament fabrication (FFF) 3D printing technology were tested for different time intervals to establish their antimicrobial activities. The results presented here depict that the sample prepared with 90% copper and 10% PLA showed the best antibacterial activity (99.5%) after just 20 min against different types of bacteria as compared to the other samples. The metallic-enriched PLA-based antibacterial sheets were remarkably effective against Staphylococcus aureus and Escherichia coli; therefore, they can be a good candidate for future biomedical, food packaging, tissue engineering, prosthetic material, textile industry, and other science and technology applications. Thus, antimicrobial sheets made from PLA mixed with metallic particles offer sustainable solutions for a wide range of applications where touching surfaces is a big concern.

Decontamination of Geobacillus Stearothermophilus using the Arca Aerosolized Hydrogen Peroxide decontamination system.

INTRODUCTION: In response to the limited supply of personal protective equipment during the pandemic caused by SARS-CoV-2, recent studies demonstrate that gaseous H2O2 is an effective decontaminant of N95 filtering facepiece respirators to enable reuse of these items in a clinical setting. This paper evaluates the efficacy of the Arca Aerosolized Hydrogen Peroxide Decontamination System (Arca), a novel aerosolized H2O2 decontamination system, using biologic indicator testing. MATERIALS AND METHODS: The Arca produces and circulates H2O2 aerosol inside of a sealed stainless steel chamber. The Arca's decontamination efficacy was evaluated in 8 decontamination trials with 2 H2O2 concentrations (3% and 12%) and 4 decontamination cycle durations (45, 60, 90, and 120 minutes). Efficacy was evaluated by testing: 1) the concentration in parts per million (ppm) of H2O2 produced inside the chamber and the concentration in ppm of H2O2 vented from the chamber, and 2) the decontamination of Mesa Biologic Indicator filter strips (BI) inoculated with Geobacillus Stearothermophilus. Control tests were conducted by submerging BI strips in 3mL of 3% and 12% H2O2 for 120 minutes (negative controls) and by not exposing one BI strip to H2O2 (positive control). RESULTS: Greater than 5000 ppm of H2O2 was detected on the concentration strips inside the chamber for each of the eight decontamination trials. No vented H2O2 was detected on the external concentration strips after any decontamination trial. No growth was observed for any of the negative controls after seven days. The positive control was positive for growth. CONCLUSION: The Arca Aerosolized Hydrogen Peroxide Decontamination System is effective at decontaminating bacterial G. Stearothermophilus at a cycle time of 45 minutes utilizing 6mL of 3% H2O2 solution.

Efficacy of hydrogen peroxide wipes for decontamination of AZD1222 adenovirus COVID-19 vaccine strain on pharmaceutical industry materials.

This study aimed to evaluate the performance of accelerated hydrogen peroxide® wipes (HPW) for decontamination of the chimpanzee adenovirus AZD1222 vaccine strain used in the production of recombinant COVID-19 vaccine in a pharmaceutical industry. Two matrices were tested on stainless-steel (SS) and low-density-polyethylene (LDP) surfaces: formulated recombinant COVID-19 vaccine (FCV) and active pharmaceutical ingredient (API). The samples were spiked, dried and the initial inoculum, possible residue effect (RE) and titre reduction after disinfection with HPW were determined. No RE was observed. The disinfection procedure with HPW resulted in complete decontamination the of AZD1222 adenovirus strain in FCV (≥7·46 and ≥7·49 log10 infectious unit [IFU] ml-1 for SS and LDP carriers respectively) and API (≥8·79 and ≥8·78 log10 IFU ml-1 for SS and LDP carriers respectively). In conclusion, virucidal activity of HPW was satisfactory against the AZD1222 adenovirus strain and can be a good option for disinfection processes of SS and LPD surfaces in pharmaceutical industry facilities during recombinant COVID-19 vaccine production. This procedure is simple and can be also applied on safety unit cabins and sampling bags made of LDP as well.

Novel chlorine-extending polymer coating with prolonged antiviral activity against SARS-CoV-2.

We previously reported a novel polymeric surface coating, namely, HaloFilm™ that can immobilize and extend the antimicrobial activity of chlorine on surfaces. In this study, we demonstrated the continuous antiviral efficacy of HaloFilm when applied on stainless steel and cotton gauze as two representative models for non-porous and porous surfaces against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Forty-eight hours post HaloFilm application and chlorination and 2 h post the viral challenge, the inoculum titre was reduced by 2.25 ± 0.33 and ≥4.36 ± 0.23 log10 TCID50 on non-porous and porous surfaces, respectively. The half-life of the virus was shorter (13.86 min) on a HaloFilm-coated surface than what has been reported on copper (46.44 min).

Comparison of Surface Persistence of SARS-CoV-2 Alpha and Delta Variants on Stainless Steel at 4°C and 24°C.

Most studies on surface persistence of SARS-CoV-2 have been conducted at temperatures between 20°C and 30°C. There is limited data on the survival of SARS-CoV-2 at low temperatures. In this study, the stability of SARS-CoV-2 Alpha and Delta variants on stainless steel was investigated at two temperatures (4°C and 24°C). The results show that both variants decayed more rapidly at 24°C compared with 4°C. At 24°C, Alpha and Delta variants showed reductions of 0.33 log10 and 1.02 log10, respectively, within the first 2.5 h. However, at 4°C, Alpha variant showed a reduction of 0.16 log10 within the first 2.5 h while no reduction was observed with Delta variant. After remaining in situ for 24 h at 24°C, log10 reductions of 2.66 (Alpha) and 3.11 (Delta) were observed. No viable Alpha and Delta variant was recovered after 48 h and 72 h, respectively. After 24 h in a refrigerated environment (4°C) log10 reductions of 1.16 (Alpha) and 0.95 (Delta) were observed. Under these experimental conditions, both viruses survived on stainless steel for at least 1 week. No viable Alpha and Delta variant was recovered after 10 days. These findings support the potential for increased fomite transmission of SARS-CoV-2 during winter months in colder regions worldwide and in some industrial sectors. IMPORTANCE Human transmission is believed to occur primarily through direct transfer of infectious droplets or aerosols. However, fomite transmission through contact with contaminated surfaces may also play an important role. This study provides novel evidence comparing the stability of Alpha and Delta variants on stainless steel surfaces at 4°C and 24°C. At 4°C both variants were found to be still detectable for up to 7 days. At 24°C Delta variant could be recovered over 2 days compared with Alpha variant which could not be recovered after 2 days. This has implications for fomite transmission interventions for people living and working in cold environments.

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.

No-Touch Automated Disinfection System Based on Hydrogen Peroxide and Ethyl Alcohol Aerosols for Use in Healthcare Environments.

Healthcare-related infections are sustained by various bacteria and fungi. In recent years, various technologies have emerged for the sanitation of healthcare-related environments. This study evaluated the effectiveness of a no-touch disinfection system that aerosolizes 5% hydrogen peroxide and 10% ethyl alcohol. After selecting an environment, the Total Bacterial Count and the Total Fungal Count in the air and on a surface of the room were determined to evaluate the effectiveness of the aerosolization system. In addition, sterile stainless-steel plates inoculated with S. aureus, P. aeruginosa, and Aspergillus spp. isolated from hospitalized patients and reference strains were used to evaluate the effectiveness of the system. For each organism, three plates were used: A (cleaned), B (not cleaned), and C (control). The A plates were treated with non-ionic surfactant and the aerosolization system, the B plates were subjected to the aerosolization system, and the plates C were positioned outside the room that was sanitized. Following sanitization, air and surface sampling was conducted, after which, swabs were processed for bacterial and fungal enumeration. The results showed that the air sanitization system had good efficacy for both bacteria and fungi in the air and on stainless-steel plates, particularly for the A plates.

Survival of SARS-CoV-2 in artificial seawater and on the surface of inanimate materials.

There is a potential risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread through human contact with seafood and the inanimate materials contaminated by the virus. In this study, we examined the stability of the virus in artificial seawater (ASW) and on the surface of selected materials. SARS-CoV-2 (3.75 log10 TCID50 ) in ASW at 22℃ maintained infectious about 3 days and at 4℃ the virus survived more than 7 days. It should be noticed that viable virus at high titer (5.50 log10 TCID50 ) may survive more than 20 days in ASW at 4℃ and for 7 days at 22℃. SARS-CoV-2 on stainless steel and plastic bag maintained infectious for 3 days, and on nonwoven fabric for 1 day at 22℃. In addition, the virus remained infectious for 9 days on stainless steel and non-woven fabric, and on plastic bag for 12 days at 4℃. It is important to highlight the role of inanimate material surfaces as a source of infection and the necessity for surface decontamination and disinfection.

A comparison of persistence of SARS-CoV-2 variants on stainless steel.

The survival of newer variants of SARS-CoV-2 on a representative surface has been compared to the established UK circulating isolate to determine whether enhanced environmental stability could play a part in their increased transmissibility. Stainless steel coupons were inoculated with liquid cultures of the three variants, with coupons recovered over seven days and processed for recoverable viable virus using plaque assay. After drying, there was no significant difference in inactivation rates between variants, indicating that there is no increased environmental persistence from the new variants.

Validation of the VIRSeek SARS-CoV-2 Mplex Assay for Detection of SARS-CoV-2 on Stainless-Steel Surfaces: AOAC Performance Tested MethodSM 122006.

BACKGROUND: The Eurofins GeneScan Technologies' VIRSeek SARS-CoV-2 Mplex kit is a RT (reverse transcription) real-time polymerase chain reaction (RT-qPCR) assay for the detection of two targets on the N-gene (nucleocapsid) of SARS-CoV-2. An extraction control, that allows monitoring of the extraction procedure and PCR inhibition, is included. OBJECTIVE: In silico analysis and wet testing showed inclusivity and exclusivity of the assay. The complete workflow starting from surface swabbing (VIRSeek PATHOSwab kit), RNA extraction (VIRSeek RNAExtractor), RT-PCR (VIRSeek SARS-CoV-2 Mplex), and evaluation with FastFinder was validated in comparison to the CDC method for detection of SARS-CoV-2 on stainless steel. METHOD: In silico analysis was performed by using the MFOLD online program. The matrix study was performed for stainless steel inoculated with SARS-CoV-2 isolated from the first documented US case of a traveler from Wuhan, China. RESULTS: For inclusivity, 15 764 sequences were analyzed and all mismatches (0.37% of the sequences had single mismatches) were considered non-critical. Cross reactivity for closely related viruses and background organisms was performed, resulting in correct exclusion of all. No significant differences were observed for the probability of detection (POD) study when comparing to the CDC method. CONCLUSIONS: Results of the inclusivity and exclusivity study show that the assay is specific for detection of SARS-CoV-2. The POD study showed no statistically significant difference compared to the CDC reference method, results were identical for the uninoculated and the high level. For the fractional recovery level, the candidate method detected 9/17 samples leading to a POD of 0.47, the reference method detected 11/20 samples leading to a POD of 0.55. HIGHLIGHT: The complete workflow starting from swabbing of the surface (VIRSeek PATHOSwab kit), RNA extraction (VIRSeek RNAExtractor), RT-PCR (VIRSeek SARS CoV-2 Mplex) and evaluation with FastFinder was validated in comparison to the US Centers for Disease Control and Prevention method for detection of SARS-CoV-2 on Stainless Steel.

Detection of SARS-CoV-2 Virus on Stainless-Steel Surfaces: AOAC Performance Tested MethodSM 022102.

BACKGROUND: The SureFast® SARS-CoV-2 PLUS Test is a reverse transcription qPCR (RT-qPCR) assay for the direct, qualitative detection of novel coronavirus (SARS-CoV-2) RNA from stainless-steel environmental sample swabs. OBJECTIVE: To validate the SureFast SARS-CoV-2 PLUS Kit as part of the AOAC Research Institute's Emergency Response Validation Performance Tested Method(s)SM program. METHOD: The SureFast SARS-CoV-2 PLUS Kit was evaluated for specificity using in silico analysis of 15 764 SARS-CoV-2 sequences and 65 exclusivity organisms (both near neighbors and background organisms) using the ThermoBLAST program. The candidate method was evaluated in an unpaired study design for one environmental surface (stainless steel) and compared to the US Centers for Disease Control and Prevention 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel, Instructions for Use (Revision 4, Effective 6/12/2020). RESULTS: Results of the in silico analysis demonstrated 99.99% selectivity of the method in being able to detect target sequences of the known CoV-2 genomes and discriminate them from near neighbors. In the matrix study, the candidate method demonstrated statistically significant better recovery of the target analyte than the PCR detection reference method. CONCLUSIONS: The SureFast SARS-CoV-2 PLUS Kit is a rapid and accurate method that can be utilized by food producers to detect the causative agent of COVID-19 on stainless-steel contact surfaces. HIGHLIGHTS: SureFast SARS-CoV-2 PLUS test method is highly specific for primer/probe binding to the E target genome region for the SARS-CoV-2 virus, 99.99% binding specificity using in silico analysis.

Human Coronaviruses Do Not Transfer Efficiently between Surfaces in the Absence of Organic Materials.

Human coronaviruses, including SARS-CoV-2, are known to spread mainly via close contact and respiratory droplets. However, other potential means of transmission may be present. Fomite-mediated transmission occurs when viruses are deposited onto a surface and then transfer to a subsequent individual. Surfaces can become contaminated directly from respiratory droplets or from a contaminated hand. Due to mask mandates in many countries around the world, the former is less likely. Hands can become contaminated if respiratory droplets are deposited on them (i.e., coughing or sneezing) or through contact with fecal material where human coronaviruses (HCoVs) can be shed. The focus of this paper is on whether human coronaviruses can transfer efficiently from contaminated hands to food or food contact surfaces. The surfaces chosen were: stainless steel, plastic, cucumber and apple. Transfer was first tested with cellular maintenance media and three viruses: two human coronaviruses, 229E and OC43, and murine norovirus-1, as a surrogate for human norovirus. There was no transfer for either of the human coronaviruses to any of the surfaces. Murine norovirus-1 did transfer to stainless steel, cucumber and apple, with transfer efficiencies of 9.19%, 5.95% and 0.329%, respectively. Human coronavirus OC43 transfer was then tested in the presence of fecal material, and transfer was observed for stainless steel (0.52%), cucumber (19.82%) and apple (15.51%) but not plastic. This study indicates that human coronaviruses do not transfer effectively from contaminated hands to contact surfaces without the presence of fecal material.

Stainless-steel crowns in children: Norwegian and Finnish dentists' knowledge, practice and challenges.

BACKGROUND: Stainless-steel crowns (SSCs) are recommended for restorative treatment of young teeth severely affected by caries, fractures or dental developmental disorders (DDDs). However, despite recommendations and clinical evidence, SSCs are not widely used by general dentists, who favour extraction and more conventional restorations. The present study aimed to investigate the views of and use of SSCs among Norwegian and Finnish dentists. METHODS: The present study was a cross-sectional survey among Norwegian and Finnish dentists. An electronic questionnaire was sent to Norwegian and Finnish dentists asking whether they used SSCs and on which indications. In addition, the questionnaire assessed reasons for non-use and dentists' perceptions regarding advantages and challenges in the use of SSCs, as well as the need for additional training. Distributions of background characteristics, use of and views on SSCs were calculated, and statistical significance of the associations between respondents' background and their answers were evaluated. RESULTS: Of the 574 Norwegian and 765 Finnish respondents, only 12.0% and 12.9% reported to use SSCs, respectively. The most frequently reported barrier reported by those who did not use SSCs was lack of practical training. The most frequent challenge reported by those using SSCs was difficulties in crown adjustment followed by aesthetic issues, and the most frequently reported advantage was that SSCs maintain the function and occlusion. The majority of respondents reported a need for more information and practical training in the use of SSCs, with hands-on course as their most frequently preferred education type. CONCLUSION: Although the value of SSCs for restoring young molars is recognized by Norwegian and Finnish dentists, SSCs are rarely used by general dentists. The majority of the respondents reported lack of training and materials and was interested in receiving more information and education.

Validation Study for VERIPRO® SARS-CoV-2 Env Assay for the Detection of SARS-CoV-2 from Stainless-Steel Environmental Surface Swabs: Emergency Response Validation-AOAC Performance Tested MethodSM 122001.

BACKGROUND: The VERIPRO® SARS-CoV-2 Env assay uses reverse transcriptase (RT) PCR to detect SARS-CoV-2, the causative agent of COVID-19, from stainless-steel environmental sample swabs. OBJECTIVE: To validate the VERIPRO SARS-CoV-2 Env assay as part of the AOAC Research Institute's Emergency Response Validation Performance Tested Method(s)SM program. METHOD: The VERIPRO SARS-CoV-2 Env assay was evaluated for specificity using in silico analysis of 15 764 SARS-CoV-2 sequences and 65 exclusivity organisms (both near neighbors and background organisms). The candidate method was evaluated in an unpaired study design for one environmental surface (stainless steel) and compared to the U.S. Centers for Disease Control and Prevention 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel, Instructions for Use (Revision 4, Effective 6/12/2020). RESULTS: Results of the in silico analysis demonstrate the specificity of the method in being able to detect target sequences and discriminate them from near neighbors. In the matrix study, the candidate method demonstrated statistically significant better recovery of the target analyte than the reference method. CONCLUSIONS: The VERIPRO SARS-CoV-2 Env assay is a rapid and accurate method that can be utilized by food producers to detect the causative agent of COVID-19 on food contact surfaces. HIGHLIGHTS: The VERIPRO SARS-CoV-2 Env assay can be performed without the need for an optional RNA purification step to detect SARS-CoV-2 from environmental surfaces.

Validation Study for PathogenDx EnviroX-Rv Assay for the Detection of SARS-CoV-2 from Stainless Steel Environmental Surface Swabs Performance Tested MethodSM 122003.

BACKGROUND: The PathogenDx EnviroX-Rv uses endpoint PCR + DNA microarray technology to detect SARS-CoV-2, the causative agent of COVID-19, from stainless-steel environmental sample swabs. OBJECTIVE: To validate the PathogenDx EnviroX-Rv assay as part of the Emergency Response Validation (ERV) Performance Tested Method(s)SM (PTM) program. METHOD: The PathogenDx EnviroX-Rv assay was evaluated for specificity using in silico analysis of ≥41 000 SARS-CoV-2 sequences and over 50 exclusivity organisms (both near neighbors and background organisms). The candidate method was evaluated in an unpaired study design for one environmental surface (stainless steel) and compared to the US Centers for Disease Control and Prevention (CDC) 2019-Novel Coronavirus (2019-nCoV) Real-Time-Polymerase Chain Reaction (RT-PCR) Diagnostic Panel, Instructions for Use (Revision 4, Effective 6/12/2020). RESULTS: Results of the in silico analysis demonstrated the high specificity of the method in being able to detect target SARS-CoV-2 sequences and discriminate them from near neighbors and environmental background organisms. In the matrix study, the candidate method demonstrated a statistically significant difference when compared to the results of the CDC method utilized in this study, with the candidate method resulting in more positive replicates as it only requires one target to be present for a positive sample. CONCLUSIONS: The EnviroX-Rv assay rapidly and accurately detected SARS-CoV-2 RNA on environmental swabs from stainless-steel surfaces at a concentration of 2000 genomic copies per 2 × 2" test area. HIGHLIGHTS: The EnviroX-Rv assay employs dual PCR and hybridization techniques to provide highly accurate results when detecting SARS-CoV-2 from surfaces.

Validation of the Thermo Scientific™ SARS-CoV-2 RT-PCR Detection Workflow for the Detection of SARS-CoV-2 from Stainless-Steel Environmental Surface Swabs: AOAC Performance Tested MethodSM 012103.

BACKGROUND: The Thermo Scientific™ SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) Detection Workflow, packaged with Applied Biosystems™ TaqMan™ 2019-nCoV Assay Kit v1 targets three different SARS-CoV-2 genomic regions in a single RT-PCR reaction. OBJECTIVE: To validate the Thermo Scientific SARS-CoV-2 RT-PCR Workflow, for the detection of SARS-CoV-2 virus on stainless-steel surfaces as part of the AOAC Performance Tested MethodSM Emergency Response Validation program. METHOD: The Applied Biosystems TaqMan 2019-nCoV Assay Kit v1, as part of the Thermo Scientific SARS-CoV-2 RT-PCR Workflow, was evaluated for specificity using in silico analysis of 15 764 SARS-CoV-2 sequences and 65 exclusivity organisms. The Thermo Scientific SARS-CoV-2 RT-PCR Workflow was evaluated in an unpaired study for one environmental surface (stainless steel) and compared to the U.S. Centers for Disease Control and Prevention 2019-Novel Coronavirus RT-PCR Diagnostic Panel, Instructions for Use (Revision 4, Effective 6/12/2020). RESULTS: In silico analysis showed that, of the 15 756 target SARS-CoV-2 genomes analyzed, 99% of the strains/isolates are perfectly matched to at least two of the three assays, and more than 90% have 100% homology to all three assays (ORF1ab, N-gene, S-gene) in the SARS-CoV-2 Kit. None of the 65 non-target strain genomes analyzed showed matching sequences. In the matrix study, the Thermo Scientific SARS-CoV-2 workflow showed comparable detection to the centers of disease control and prevention (CDC) method. CONCLUSIONS: The Thermo Scientific SARS-CoV-2 RT-PCR Workflow is an effective procedure for detection of RNA from SARS-CoV-2 virus from stainless steel. HIGHLIGHTS: The workflow provides equivalent performance results with the two tested RNA extraction platforms and the two tested RT-PCR instruments.

Validation of the COVID-19 Indoor Test™ by Phylagen for Detection of SARS-CoV-2 Virus on Stainless-Steel Surfaces: AOAC Performance Tested MethodSM 122004.

BACKGROUND: The COVID-19 Indoor Test™ by Phylagen uses a real-time PCR Assay to detect nucleic acid from SARS-CoV-2, the causative agent of COVID-19, which is extracted from swabs sampled from environmental surfaces. This information can be used to detect the presence of the virus in indoor environments. OBJECTIVE: To validate the COVID-19 Indoor TestTM by Phylagen as part of the AOAC Research Institute's Emergency Response Validation Performance Tested Method(s)SM program. METHOD: The COVID-19 Indoor Test by Phylagen assay was evaluated for specificity using in silico analysis of 15 764 SARS-CoV-2 sequences and 65 exclusivity organisms. The candidate method was also evaluated in an unpaired matrix study design for one environmental surface (stainless steel) and compared to the U.S. Centers for Disease Control and Prevention 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel (Revision 4, Effective 6/12/2020). RESULTS: Results of the in silico analysis demonstrated the specificity of the method in being able to detect SARS-CoV-2 target sequences and discriminate them from near-neighbors. In the matrix study, the candidate method demonstrated statistically significant better recovery of the target analyte than the reference method (2 × 103 GU/2 × 2" test surface). CONCLUSIONS: The COVID-19 Indoor Test by Phylagen is a rapid and accurate method that can be utilized to monitor the presence of SARS-CoV-2, the causative agent of COVID-19, on stainless-steel surfaces in built environments. HIGHLIGHTS: The COVID-19 Indoor Test by Phylagen assay performed significantly better than the reference method when used to detect SARS-CoV-2 from environmental surfaces.

Comparison of the Modified Centers for Disease Control and Prevention 2019-Novel Coronavirus Real-Time RT-PCR Method for Detection of Infectious and Heat-Inactivated Virus on Stainless Steel.

BACKGROUND: Infectious Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) was used in the validation of methods for detection of SARS-CoV-2 on stainless-steel surfaces in the AOAC Research Institute Emergency Response Validation project. Handling infectious virus requires Biosafety Level (BSL)-3 facilities. OBJECTIVE: To compare the recovery and detection of infectious and heat-inactivated (HI; 65°C for 30 min) SARS-CoV-2 from stainless steel by the modified US Centers for Disease Control and Prevention (CDC) 2019-Novel Coronavirus (2019-nCoV) Real Time Reverse Transcription Polymerase Chain Reaction (RT-PCR) Diagnostic Panel. METHOD: Viral stocks were diluted in viral transport medium (VTM) and deposited onto stainless-steel test areas at 2 × 103 and 2 × 104 genomic copies for low and high, respectively. Test areas were sampled and aliquots of the resulting test solutions analyzed by RT-qPCR according to the CDC method. Results were analyzed by probability of detection (POD) statistics. RESULTS: The low level, where fractional positive results (25-75%) are expected, yielded PODI = 0.80 (0.58, 0.92) for the infectious virus and PODHI = 0.15 (0.05, 0.36) for the HI virus. The bias, dPODHI = -0.65 (-0.80, -0.35), demonstrated a statistical difference between infectious and HI virus detection. No difference was observed at the high inoculation level. CONCLUSIONS: Despite the statistical difference observed, the use of the HI virus is a viable alternative for matrix extension studies using a method comparison study design. Highlights: The use of HI SARS-CoV-2 can mitigate the need for a BSL-3 facility for matrix extension validation of alternative methods in SARS-CoV-2 studies. HIGHLIGHTS: The use of HI SARS-CoV-2 can mitigate the need for a BSL-3 facility for matrix extension validation of alternative methods in SARS-CoV-2 studies.