Evaluation of ozonated water using ASTM E1174 for standardized testing of handwash formulations for healthcare personnel

Evaluation of the microbial reduction efficacy and perception of use of an ozonized water spray disinfection technology

The development of new approaches for the decontamination of surfaces is important to deal with the processes related to exposure to contaminated surfaces. Therefore, was evaluated the efficacy of a disinfection technology using ozonized water (0.7–0.9 ppm of O₃) on the surfaces of garments and accessories of volunteers, aiming to reduce the spread of microbial pathogens in the workplace and community. A Log₁₀ microbial reduction of 1.72–2.40 was observed between the surfaces tested. The microbial reductions remained above 60% on most surfaces, and this indicated that the disinfection technology was effective in microbial log reduction regardless of the type of transport used by the volunteers and/or their respective work activities. In association with the evaluation of efficacy, the analysis of the perception of use (approval percentage of 92.45%) was fundamental to consider this technology as an alternative for use as a protective barrier, in conjunction with other preventive measures against microbiological infections, allowing us to contribute to the availability of proven effective devices against the spread of infectious agents in the environment.

Evaluation of the Antimicrobial Effectiveness of Ozonated Water for Hand Washing in the Presence of Organic Material Contamination Using the ASTM E2946-13 Standard Test Method

ABSTRACT

Ozonated water is a possible hand washing alternative to antimicrobial soap and water. In a previous report, 4 ppm of ozonated water removed artificially contaminated bacteria from the hands of healthy volunteers as effectively as antimicrobial or nonantimicrobial soap and water. Currently, there is a lack of data on the efficacy of ozonated water in removing bacteria from hands loaded with organic materials. This study aimed to evaluate the effectiveness of ozonated water in removing bacteria from hands contaminated with organic material, according to the American Society for Testing and Materials E2946-13. Sixteen healthy volunteers were randomly assigned to the ozonated water group and the antimicrobial soap and water group. Their hands were contaminated with an avirulent strain of Escherichia coli in beef broth suspension. Approximately 3-log CFU bacterial reductions between baseline and postwash colonies were observed on the hands in both groups. Ozonated water may remove bacteria from hands contaminated with organic material with similar effectiveness as antimicrobial soap and water.

HIGHLIGHTS

Inactivation of SARS-CoV-2 by Ozonated Glycerol

We evaluated the SARS-CoV-2-inactivation activity of ozonated glycerol (OG). When a viral solution with 1% fetal bovine serum (FBS) was mixed with test solutions at a ratio of 1:19 and incubated for 20 s, OG with ozone concentrations of over 1000 ppm inactivated ≥ 94.38% of the virus. Extension of the reaction time to 1 h led to the inactivation of ≥ 99.82% of the virus (the viral titer was below the detection limit). Extension to 24 h resulted in concentrations over 200 ppm OG inactivating ≥ 99.87% of the virus (the viral titers were below the detection limit). Next, viral solutions with 1, 20, and 40% FBS were mixed with test solutions at a ratio of 1:19 and incubated for 5 min. Whereas the virucidal activity of 500 ppm OG was very limited in the presence of 1% FBS (79.47% inactivation), it increased in the presence of 20 and 40% FBS (95.13 and 97.95% inactivation, respectively; the viral titers were not below the detection limit). Meanwhile, over 1000 ppm OG inactivated ≥ 99.44% of the virus regardless of the FBS concentration (the viral titers were below the detection limit). Extension of the reaction time to 1 h led to 500 ppm OG inactivating ≥ 99.91 and ≥ 99.95% of the virus with 20 and 40% FBS, respectively (the viral titers were below the detection limit). These results suggested that OG might be useful as a virucidal agent against SARS-CoV-2.

Evaluation of the Cytotoxicity of Various Hand Disinfectants and Ozonated Water to Human Keratinocytes in a Cultured Epidermal Model

OBJECTIVE

To evaluate the cytotoxicity of various hand disinfectants and ozonated water to human keratinocytes using a cultured epidermal model.

DESIGN

Using a test protocol from the Organization for Economic Co-operation and Development, investigators applied hand disinfectants containing either 83% ethanol, 0.2% benzalkonium chloride, 0.5% povidone-iodine, 1% chlorhexidine, 1% chlorhexidine ethanol, or ozonated water to a cultured human epidermal model. Surface morphology and histologic changes were evaluated by scanning electron microscopy and hematoxylin-eosin staining.

MAIN OUTCOME MEASURES

Production of inflammatory cytokine interleukin 1α by keratinocytes and cell death rate.

MAIN RESULTS

Electron microscopic analysis revealed the creation of small holes on the stratum corneum, and hematoxylin-eosin staining revealed perinuclear vacuolation of keratinocytes and cells with a condensed nucleus. Interleukin 1α was detected in the culture supernatants. More than 80% of keratinocytes did not survive after a 15-minute application of disinfectants. However, no significant damage was detected with ozonated water.

CONCLUSIONS

Ozonated water did far less damage to keratinocytes than the tested disinfectants. Although the ability of ozonated water to disinfect hands of medical staff members requires further study, it might serve as an alternative with minimum cytotoxicity.

Technological Advances in Ozone and Ozonized Water Spray Disinfection Devices

To control infectious diseases such as the severe acute respiratory syndrome coronavirus (Covid-19) that caused the current pandemic, disinfection measures are essential. Among building measures, disinfection chambers can help to decrease the transmission rate through the sanitizing capacity of the disinfectant used, which can thereby clean surfaces or humans. Out of existing biocides, ozone is considered one of the safest for humans, but one of the most powerful oxidizers, making the substance a better alternative as the biocidal solution in disinfection chambers. Analyses were carried out by using all patented documents related to disinfection chambers that used ozone as a disinfectant. A Derwent Innovation Index (DII) database search was undertaken to find these patents. Patent prospecting resulted in 620 patent documents that were divided into 134 patent families. There was no technology related to protective barriers for individuals, and the majority of patents in the retrieved data aimed at sterilizing medical devices and surfaces. Given that the specific Cooperative Patent Classification (CPC) code for ozone dissolved in liquid was used in the methodology search, but not included among the 10 most used codes in the patents, the use of ozonized water may be an innovative approach in the technology landscape of sterilization chambers.

Effects of hand disinfection with alcohol hand rub, ozonized water, or soap and water: time for reconsideration?

The effect of alcohol hand rub was tested in eradicating Escherichia coli, and compared with hand wash using ozonized tap water or soap and water. Alcohol eradicated all bacteria in 10 out of 35 participants, but with an average (SD) of 2330 (4227) cfu/mL left after disinfection, whereas ozonized water removed all bacteria in 10 out of 55 participants, with an average of only 538 (801) cfu/mL left (P = 0.045). Soap washing was the most effective with total removal of bacteria in six out of 20 participants, with an average of 98 (139) cfu/mL (P = 0.048 and 0.018 versus ozonized water and alcohol, respectively).

Ozonized water as an alternative to alcohol-based hand disinfection

BACKGROUND

Hand hygiene plays a vital role in the prevention of transmission of micro-organisms. Ozone (O₃) is a highly reactive gas with a broad spectrum of antimicrobial effects on bacteria, viruses, and protozoa. It can easily be produced locally in small generators, and dissolved in tap water, and quickly transmits into ordinary O₂ in the surrounding air.

AIM

To compare ozonized tap water and alcohol rub in decontamination of bacterially contaminated hands.

METHODS

A cross-over study among 30 nursing students. Hands were artificially contaminated with Escherichia coli (ATCC 25922), then sanitized with ozonized tap water (0.8 or 4 ppm) or 3 mL standard alcohol-based rub (Antibac 85%). The transient microbes from fingers were cultivated and colony-forming units (cfu)/mL were counted. The test procedure was modified from European Standard EN 1500:2013.

FINDINGS

All contaminated hands before disinfection showed cfu >30,000/mL. The mean (SD) bacterial counts in (cfu/mL) on both hands combined were 1017 (1391) after using ozonized water, and 2337 (4664) after alcohol hand disinfection. The median (range) values were 500 (0-6700) and 250 (0-16,000) respectively (non-significant difference). Twenty per cent of participants reported adverse skin effects (burning/dryness) from alcohol disinfection compared with no adverse sensations with ozone.

CONCLUSION

Ozonized tap water is an effective decontaminant of E. coli, and it could be an alternative to traditional alcohol-fluid hand disinfectants both in healthcare institutions and public places. Ozonized water may be especially valuable for individuals with skin problems.