Factors affecting decontamination of N95 masks for reuse: Feasibility & practicality of various methods.

The SARS-CoV-2 pandemic has led to an enormous increase in cases worldwide in a short time. The potential shortage might call for the reuse of personal protective equipment especially N95 masks. In this review, the methods available for decontamination of N95 masks have been compared to highlight the advantages and efficacies of different methods. Studies conducted to evaluate the biocidal efficacy, effect on filtration efficacy of the decontamination method, and maintenance of structural integrity of masks, were reviewed. Ultraviolet germicidal irradiation (UVGI) and hydrogen peroxide (H2O2) vapour were the most commonly evaluated interventions and showed good germicidal activity without significant deleterious effects on mask performance. Vapourous H2O2 was the best method as it maintained NIOSH (The National Institute for Occupational Safety and Health) recommendations of the mask on re-use and additionally, one mask could be decontaminated and reused 30 times. Ethylene oxide (EtO) preserved the maximum filtration efficacy and flow resistance. Chemical and heat-based methods had the advantages of being cost-effective and feasible but affected the structural integrity and fit of the masks. For the decontamination of N95 masks, among the heat-based methods steam was found to be the best for low middle-income countries setting. H2O2-based methods, UVGI, and EtO all exhibited both adequate biocidal efficacies and functionality (fit testing and structural integrity). Further studies on logistics, healthcare worker acceptability of reuse, and actual efficacy of protection against SARS-CoV-2 infection should be carried out to validate the use of decontamination in the real-life settings.

In vitro antimicrobial effect and mechanism of action of plasma-activated liquid on planktonic Neisseria gonorrhoeae.

Neisseria gonorrhoeae (Ng) is highly resistant to treatment, and there is an urgent need for new treatments to alleviate gonococcal resistance caused by antibiotic monotherapy. The antimicrobial effect and mechanism of plasma-activated liquid (PAL) on Ng were evaluated in this study. Upon PAL treatment, extensively analyses on cell culturability, metabolic capacity, intracellular reactive oxygen species (ROS),membrane integrity and nucleic acids for Ng were carried out and significant antimicrobial effects observed.PAL exerted antibacterial effect on Ng and induced bacterial death (6.71-log) following immersion for 30 min and treatment for 120 s. However, bacterial viability test revealed that after immersion in the same PAL, 10.17% of bacteria retained their metabolic capacity. This indicates that bacteria enter a physiological viable but non-culturable state to protect themselves from environmental stress. Confocal fluorescence microscopy and transmission electron microscopy demonstrated that PAL exerts bactericidal effect on Ng and disrupts its morphological structure. PAL may upregulate inflammatory factors and genes to modulate the resistance of Ng and affect the immune status of the host during infection.

Application of EN 16615 (4-Field Test) for the Evaluation of the Antimicrobial Activity of the Selected Commercial and Self-Made Disinfectant Wipes.

The purpose of disinfectants is to reduce microorganisms on a contaminated surface and to prevent the spread of microorganisms. The relatively new EN 16615 simulates disinfection by wiping and allows for assessing the recovery of microorganisms from the surface and, importantly, the degree of spread of microorganisms when the surface is disinfected by wiping. For the first time, using this standard, the tested products in the form of commercial disinfectant wipes were compared with self-made wipes soaked in respective disinfectant liquids. The disinfected surfaces were simulated by homogeneous polyvinyl chloride plates. The studies were carried out not only with the standard, but also with clinical multidrug-resistant microbial strains. Based on the research, it can be concluded that the most effective products in the disinfection process (log10 reduction of ≥5) with the shortest contact time (1 min) were products containing ethanol, propanol, and quaternary ammonium compounds (self-made wipes) and propanol (commercial wipes). The least effective products (log10 reduction of <5) in terms of the contact time declared by the manufacturer were products containing ethanol and sodium hypochlorite (commercial wipes). Much better antimicrobial activity of self-made wipes was observed in comparison to the activity of the commercial wipes.