Safety of Prolonged Exposure of Human Skin to Aqueous Ozone in a Test Hand Hygiene Model.

AIMS: This research assessed the safety of aqueous ozone (AO) on human skin after multiple exposures for up to 40 hours. METHODS AND RESULTS: Full thickness recombinant human skin (EpiDerm FT, EFT-400) was exposed to AO for 7 seconds per minute for the first 6 minutes of each hour, repeated hourly over four time periods (4, 10, 20 and 40 hours). An MTT assay assessed viability of skin cells after exposure, compared to incubator control, negative control and vehicle control (distilled water). No significant difference in tissue viability was found between the AO condition and any of the control conditions through 20 hours of exposures. At 40 hours of exposure, tissue viability was lower in the AO group when compared with negative control (p = 0.030) but not the other controls. CONCLUSIONS: The current study supports further consideration of repeated application of AO on human skin, such as for hand hygiene. IMPACT STATEMENT: The present research is the first well-controlled in vitro study assessing the cytotoxicity of repeated exposures of AO on a full-thickness human skin model. This information helps to inform the evaluation of AO as a potential alternative for hand and wound antisepsis.

In vitro inactivation of SARS-CoV-2 by ozonated water via novel hand hygiene device.

AIMS: The COVID-19 pandemic has heightened awareness of the need for novel surface disinfectants and hand-hygiene modalities. Ozone gas is an effective surface disinfectant, but toxicity limits its use in human applications. Ozonated water is a safer means to use ozone for disinfection, especially for human antisepsis. However, there are little data available regarding the effectiveness of ozonated water in eliminating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). METHODS AND RESULTS: This study utilizes a novel hand hygiene device that produces a stable ozone concentration of 0.5 +/-0.1 ppm in water and applies it using a proprietary spray that controls droplet size, velocity, and direction. The Device was used to apply ozonated water to a known quantity of SARS-CoV-2 Delta Variant viral particles on a non-porous surface (glass) for seven seconds. Post-exposure growth was compared to the unexposed matched control utilizing the Spearman-Karber method. Compared to control, ozonated water decreased SARS-CoV-2 viral growth by a mean log10 reduction of 4.33, or >99.99% reduction. CONCLUSIONS: These results suggest that the ozonated water, when applied by a spray hand hygiene device, is highly effective at surface disinfection of SARS-CoV-2.

Risks of ozonated oil and ozonated water on human skin: A systematic review.

Ozonated water and oil are emerging as potential dermatologic therapeutics, particularly for the treatment of various wounds. However, the safety of these liquids has not been extensively studied. The aim of this systematic review was to evaluate the risks of ozonated liquids to human skin tissue based on the available literature. We completed a structured search of five scientific databases and identified 378 articles for consideration. Based on pre-established inclusion/exclusion criteria, nine studies were included in this review. Two studies specifically evaluated the cytotoxicity of ozonated liquids on human cells, five studies evaluated ozonated liquids in randomised controlled trials (RCTs), one was a post-market surveillance study, and one was a crossover study in humans. None of the included studies found any significant human dermatologic risks associated with ozonated water or liquid. Because of the small sample size, however, additional short- and long-term RCTs specifically designed to evaluate the dermatological risks of ozonated liquids are recommended.

Validation of a global measure of faculty's clinical teaching performance.

PURPOSE: To validate the University of Michigan Global Rating Scale (GRS), a single-item, five-point global measure of faculty members' clinical teaching performances previously shown to be reliable. METHOD: In June 1998, 98 senior medical residents (98% of seniors) from four academic institutions completed the GRS for all teaching faculty at their institutions. Each resident also completed the 26-item Stanford Faculty Development questionnaire (SFDP26) for ten faculty with whom he or she had had teaching contact during residency. The SFDP26 is a validated instrument that measures seven specific aspects of clinical teaching (e.g., communication of goals, feedback). RESULTS: The mean GRS score (SE) was 3.83 (.07). There was no difference in mean GRS or SFDP26 subscale scores across institutions. In a random-effects model that controlled for interrater reliability, correlation coefficients comparing the mean GRS scores and the mean scores for the individual SFDP26 subscales ranged from.86 to.98. CONCLUSIONS: The GRS correlates highly with measures of seven specific aspects of teaching effectiveness among senior medical residents. The GRS is a simple, readily administered measure of faculty's teaching performances that can be used by residency programs as part of an incentive or reward program, to identify teachers as potential candidates for faculty development, or for consideration in promotion decisions.