Effectiveness of copper as a preventive tool in health care facilities. A systematic review

Does Extreme Wettability Matter: The Effect of Copper Wettability on Infection Spread through Hospital Surfaces

One of the reasons for the widespread occurrence of hospital-acquired infections is the ability of microorganisms to survive for extended periods on the indoor surfaces of healthcare facilities. Although the antibacterial properties of copper are well-known and have already been used in medical practice, there is still a lack of research on how extreme wettability of copper-based materials by biological fluids can affect the reduction of surface contamination and, consequently, the spread of hospital-acquired infections, particularly in healthcare settings. This study aims to compare the efficacy of superhydrophilic and superhydrophobic copper surfaces on high-touch facilities such as elevator buttons with smooth copper and stainless steel surfaces in preventing the transfer of infections through hospital surfaces. It was found that the wettability of frequently touched surfaces like elevator buttons matters for combating bacterial contamination. The total aerobic microbial counts, encompassing both pathogenic and nonpathogenic microbial contamination, were similar across smooth, superhydrophobic, and superhydrophilic copper coatings. At the same time, surfaces with extreme wettability exhibited a lower incidence of Staphylococcus aureus growth, no growth of Acinetobacter spp., and reduced maximum contamination levels for both pathogens and nonpathogenic bacteria. Superhydrophilic buttons treated with the quaternary ammonium compound miramistin showed a reduction in microbial growth during the initial 20 days. The study emphasizes the importance of surface wettability and texture in mitigating microbial contamination.

Copper in human health: From COVID 19 to neurodegenerative diseases

Copper (Cu) exists in two oxidation states Cu+I and Cu+II yielding formation of enzymes involved in biological processes. In higher concentrations, by oxidative process and ROS production, Cu is toxic towards plants, humans and animals livers as observed in Wilson disease or sheep scrapie. Fighting according to the Fenton reaction against bacteria and viruses, has been proposed as a mean of combatting nosocomial diseases and complementary to COVID19 vaccination. In humans, Cu is stocked in liver, muscle or bound to brain protein as ß-APP, tau-protein, α-synuclein, ubiquitin or prion which present antioxidant properties when Cu-bonded. In abnormal ß-sheet conformation, they can trigger neurodegenerative diseases such as Alzheimer(AD), Parkinson(PD) and ALS. In these diseases, blood copper increase correlated with brain copper decrease has been described. In AD, abnormal D-serine has been detected in blood and cerebrospinal fluid. D-glutamate and D-alanine blood levels have been found in AD and could also be controlled with Cu and ceruloplasmin in a possible disease screening test. This abnormal D-conformation might result from epimerization of physiologically L-conformation brain peptides into protease-resistant D-enantiomers. This has previously been experimentally demonstrated for Bovine Spongiform Encephalopathy in a free Cu reductive medium with UV-induced free radicals. The Cu brain protective effect against free radicals was restored with cupric addition in oxidizing medium. Cupric supplementation in the brain, might restore Cu protection and slow down neurodegenerative processes. To lower side effects, Cu amino-acid complexes able to cross the blood brain barrier might be suggested for a Cu transfer to the brain.

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.