Antiviral properties of a probiotic-based detergent system: implications for CVID-19 prevention

Background: The ongoing COVID-19 pandemic has highlighed the need for effective decontamination sanitation procedures, but these should consider the even larger threat of spread of antimicrobial resistance (AMR), already killing hundreds of thousands of people around the world and often complicating the care of COVID-19 patients. Indeed, the sanitation procedures based on high concentrations of chemical disinfectants show limitations, as they have a temporary effect, high environmental impact, and might further spur AMR. Based on previous results obtained by our group showing that an eco-sustainable sanitation system involving remodulation of hospital microbiome by selected probiotic Bacillus could stably reduce resistant pathogens (-80%) and related infections (-52%), the aim of this study was to assess the antiviral properties of such system. Methods: In vitro tests were performed to assess the antiviral activity of the probiotic-based sanitation (PBS) against enveloped viruses, including human coronavirus 229E, vaccinia virus, herpesvirus type 1, flu viruses (human and animal strains), and SARS-CoV-2. PBS activity was analyzed both in solution and on hard non-porous surfaces, at different concentrations and times of contact, evaluating the effectiveness both in removing and preventing virus contamination. Results: PBS significantly decreased the virus contamination in solution and on surfaces, with times of application comparable to those required for antiviral action certification of products (UNI EN 14476, UNI EN 16777:2019). Notably, the system could induce a >4Log decrease of virus load in maximum 2 hours, depending by the virus type. Full action was observed against SARS-CoV-2 and even against the most resistant enveloped viruses (vaccinia virus). Notably, the effect was maintained during time, contrary to most disinfectants. Conclusion: The COVID-19 pandemic has had an immense impact on infection prevention and control methods, and disinfection interventions in the healthcare settings have been implemented. However, SARS-CoV-2 is indeed detected in the hospital environment, and massive use of disinfectants might increase AMR pathogens. Based on our results, PBS could respond to the urgent need of systems able to stably decontaminating from SARS-Cov-2 without worsening AMR concern, preventing the effects of an eventual future pandemics of secondary bacterial AMR infections