One-year trial evaluating the durability and antimicrobial efficacy of copper in public transportation systems.

Surfaces on transit vehicles are frequently touched and could potentially act as reservoirs for micro-organism transmission. Regular cleaning and disinfection to minimize the spread of micro-organisms is operationally challenging due to the need to keep vehicles in circulation. The application of copper (Cu) alloys to high- touch surfaces could help reduce the risk of cross-contamination, however, little is known about the durability and efficacy of engineered copper surfaces after prolonged use. Three Cu products (decal, thermal fabrication, and alloy covers) were assessed over a 12-month period. These Cu products were randomly installed on 110 stanchions on three buses and four train (SkyTrain) cars in Vancouver and three buses, two subway cars, and two streetcars in Toronto with mirrored control surfaces directly opposite. Bacterial counts (Colony forming units, CFU) and ATP bioluminescence (ATPB) were measured every two months after peak morning routes. Durability of the Cu products were assessed monthly through visual inspection and colorimetry assays or by ex-situ microscopy. Cu products on stanchions reduced the mean colony forming units (CFU) of all vehicles by 42.7% in the mean CFU (0.573 (CI 95% 0.453-0.726), p-value < 0.001) compared to control surfaces. The three Cu products exhibited an overall 87.1% reduction in the mean ATPB readings (0.129 (CI 95% 0.059-0.285, p-value < 0.001) compared to controls. Surface Cu concentration for all three products was consistent throughout the 12-month period. Electron microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) cross-sectional analysis showed no change in thickness or dealloying of Cu products, however SEM top-down analysis revealed substantial carbon accumulation on all surfaces. Cu products installed on transit vehicles maintained antimicrobial efficacy and durability after 12 months of use.

In vitro assessment of antibacterial and antiviral activity of three copper products after 200 rounds of simulated use.

Copper has well-documented antibacterial effects but few have evaluated it after prolonged use and against bacteria and viruses. Coupons from three copper formulations (solid, thermal coating, and decal applications) and carbon steel controls were subjected to 200 rounds simulated cleaning using a Wiperator™ and either an accelerated hydrogen peroxide, quaternary ammonium, or artificial sweat products. Antibacterial activity against S. aureus and P. aeruginosa was then evaluated using a modified Environmental Protection Agency protocol. Antiviral activity against coronavirus (229E) and norovirus (MNV-1) surrogates was assessed using the TCID50 method. Results were compared to untreated control coupons. One hour after inoculation, S. aureus exhibited a difference in log kill of 1.16 to 4.87 and P. aeruginosa a log kill difference of 3.39-5.23 (dependent upon copper product and disinfectant) compared to carbon steel. MNV-1 demonstrated an 87-99% reduction on each copper surfaces at 1 h and 99% reduction at 2 h compared to carbon steel. Similarly, coronavirus 229E exhibited a 97-99% reduction after 1 h and 90-99% after 2 h. Simulated use with artificial sweat did not hinder the antiviral nor the antibacterial activity of Cu surfaces. Self-sanitizing copper surfaces maintained antibacterial and antiviral activity after 200 rounds of simulated cleaning.

In search of COVID-19: The ability of biodetection canines to detect COVID-19 odours from clinical samples.

BACKGROUND: COVID-19 continues to be a public health concern and the demand for fast and reliable screening tests remains. SARS-CoV-2 infection in humans generates a specific volatile organic compound signature; this 'volatilome' could be used to deploy highly trained canine scent detection teams if they could reliably detect odours from infected individuals. METHODS: Two dogs were trained over 19 weeks to discriminate between the odours produced by breath, sweat, and gargle specimens collected from SARS-CoV-2 infected and uninfected individuals. Third party validation was conducted in a randomized double-blinded controlled manner using fresh odours obtained from different patients within 10 days of their first positive SARS-CoV-2 molecular result. RESULTS: Cumulatively, the dogs completed 299 training sessions on odours from 108 unique participants. Validation was conducted over 2 days with 120 new odours. Twenty-four were odours collected from SARS-CoV-2 positive individuals (8 gargle, 8 sweat, and 8 breath); 21 were from SARS-CoV-2 negative individuals (5 gargle, 8 sweat, and 8 breath) and the remaining 75 were odours that the dogs could have associated with the target odour during training. The dogs were able to identify odours from positive specimens with an overall sensitivity of 100% and a specificity of 87.5%. Considering a community prevalence of 10%, the combined negative predictive value of the dogs was 100% and the positive predictive value was 47.1%. CONCLUSIONS: Multiple dogs can be trained to accurately detect SARS-CoV-2 positive individuals. Future research is required to determine how and when canine scent detection teams should be deployed.

HISTORIQUE: La COVID-19 continue d'être une préoccupation sanitaire, et la demande de tests de dépistage rapides et fiables se maintient. L'infection par le SRAS-CoV-2 chez les humains produit une signature composée organique volatile bien précise. Ce « volatilome ¼ pourrait être utilisé pour déployer des équipes canines hautement formées et spécialisées dans la détection des odeurs afin d'établir si elles peuvent détecter les odeurs des personnes infectées avec fiabilité. MÉTHODOLOGIE: Deux chiens ont été formés pendant 19 semaines pour distinguer les odeurs émanantes des échantillons d'haleine, de sueur et de gargarisme prélevés chez des personnes infectées et non infectées par le SRAS-CoV-2. Les chercheurs ont effectué une validation par des tiers dans le cadre d'une étude contrôlée randomisée à double insu au moyen d'odeurs fraîches obtenues auprès de divers patients dans les dix jours suivant le premier résultat moléculaire positif au SRAS-CoV-2. RÉSULTATS: Dans l'ensemble, les chiens ont effectué 299 séances de formation sur les odeurs de 108 participants uniques. La validation a eu lieu sur deux jours à partir de 120 nouvelles odeurs. Ainsi, 24 odeurs provenaient de personnes positives au SRAS-CoV-2 (8 échantillons de gargarisme, 8 de sueur et 8 d'haleine); 21 provenaient de personnes négatives au SRAS-CoV-2 (5 échantillons de gargarisme, 8 de sueur et 8 d'haleine) et les 75 autres étaient des odeurs que les chiens avaient pu associer à l'odeur cible pendant la formation. Les chiens ont été en mesure de dépister les odeurs des échantillons positifs selon une sensibilité globale de 100 % et une spécificité de 87,5 %. Étant donné une prévalence communautaire de 10 %, la valeur prédictive négative combinée des chiens s'élevait à 100 % et la valeur prédictive positive, à 47,1 %. CONCLUSIONS: De nombreux chiens peuvent être formés pour dépister avec exactitude les personnes positives au SRAS-CoV-2. De futures recherches devront être réalisées pour déterminer quand et comment déployer ces équipes canines spécialisées en biodétection.

Postdischarge decontamination of MRSA, VRE, and Clostridium difficile isolation rooms using 2 commercially available automated ultraviolet-C-emitting devices.

BACKGROUND: Two ultraviolet-C (UVC)-emitting devices were evaluated for effectiveness in reducing methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Clostridium difficile (CD). METHODS: Six surfaces in rooms previously occupied by patients with MRSA, VRE, or CD were cultured before and after cleaning and after UVC disinfection. In a parallel laboratory study, MRSA and VRE suspended in trypticase soy broth were inoculated onto stainless steel carriers in triplicate, placed in challenging room areas, subjected to UVC, and subcultured to detect growth. RESULTS: Sixty-one rooms and 360 surfaces were assessed. Before cleaning, MRSA was found in 34.4%, VRE was found in 29.5%, and CD was found in 31.8% of rooms. Cleaning reduced MRSA-, VRE-, and CD-contaminated rooms to 27.9%, 29.5%, and 22.7%, respectively (not statistically significant). UVC disinfection further reduced MRSA-, VRE-, and CD-contaminated rooms to 3.3% (P = .0003), 4.9% (P = .0003), and 0% (P = .0736), respectively. Surface colony counts (excluding floors) decreased from 88.0 to 19.6 colony forming units (CFU) (P < .0001) after manual cleaning; UVC disinfection further reduced it to 1.3 CFU (P = .0013). In a multivariable model of the carrier study, the odds of detecting growth in broth suspensions after UVC disinfection were 7 times higher with 1 machine (odds ratio, 6.96; 95% confidence interval, 3.79-13.4) for a given organism, surface, and concentration. CONCLUSIONS: UVC devices are effective adjuncts to manual cleaning but vary in their ability to disinfect high concentrations of organisms in the presence of protein.