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Ozonized water as an alternative to alcohol-based hand disinfection



Background: Hand hygiene plays a vital role in the prevention of transmission of microorganisms. 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 (0e6700) and 250 (0e16,000) 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.
Accepted Manuscript
Ozonized water as an alternative to alcohol-based hand disinfection
Hans Johan Breidablik, Dag Einar Lysebo, Lene Johannessen, Åse Skare, John
Roger Andersen, Ole T. Kleiven
PII: S0195-6701(19)30056-8
Reference: YJHIN 5657
To appear in: Journal of Hospital Infection
Received Date: 4 December 2018
Accepted Date: 29 January 2019
Please cite this article as: Breidablik HJ, Lysebo DE, Johannessen L, Skare Å, Andersen JR, Kleiven
OT, Ozonized water as an alternative to alcohol-based hand disinfection, Journal of Hospital Infection,
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Ozonized water as an alternative to alcohol-based hand disinfection
Hans Johan Breidablik
Center of Health Research, Førde Hospital Trust, Førde, Norway
Dag Einar Lysebo
Haukeland University Hospital, Bergen, Norway
Lene Johannessen
Thelma Indoor Air & Working Environment AS, Microbiology Department, Trondheim,
Åse Skare
Førde Hospital Trust, Department for Infection Control, Førde, Norway
John Roger Andersen
Faculty of Western Norway University of Applied Sciences, Førde, Norway
Ole T. Kleiven
Faculty of Western Norway University of Applied Sciences, Førde, Norway
Corresponding author:
Hans Johan Breidablik
Center of Health Research, Førde Hospital Trust, Svanehaugvegen 2, 6812 Førde, Norway
Tel. +47 90182853
Fax. +47 57839795
Running title:
Ozonized water in hand disinfection
Background: Hand hygiene plays a vital role in the prevention of transmission of
microorganisms. Ozone (O
) 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 O
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 a CFU-count >30,000/mL.
The average bacterial counts in (CFU/mL) on both hands combined were 1017 (SD, 1391)
after using ozonized water, and 2337 (SD, 4664) after alcohol hand disinfection. The median
values were 500 (range, 6700) and 250 (range, 16000) respectively, a non-significant
difference (P = 0.713). Twenty percent 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 could be an
alternative to traditional alcohol fluid hand disinfectants both in healthcare institutions and
public places. Ozonized water may be particularly valuable for individuals with skin
Keywords: Ozone, alcohol rub, hand disinfection, E. coli
Our interest in ozone as an alternative hand disinfectant started several years ago when two
eye surgeons in our hospitals developed hand dermatitis and had to stop performing operative
procedures. Both got permission to use ozone gas in tap water in their preoperative hand
hygiene, and this solved their skin problems. In the same period, there was an outbreak of
Giardia lamblia infection in the city of Bergen, Norway, originating from the domestic water
supply, and many kindergartens were advised to start using ozonized tap water in hand
hygiene for children, as it was known that ozone could eradicate protozoans [1]. Some
kindergartens continued using ozone as hand disinfection for several years after, and the staff
reported a clear impression that both the children and staff had fewer infectious diseases
during this period (Christine Andreassen, personal communication). We are also experiencing
a global threat from multidrug-resistant bacteria, and the need to reduce the use of broad-
spectrum antibiotics [2]. Hand disinfection has thus become even more important as a
preventive procedure.
Ozone gas (O
) was probably first detected by a Dutch chemist (van Marum), but the
first systematic studies were done by Christian Friedrich Schönbein in around 1840 [3]. He
noted the characteristic smell around an electrifier and named the gas based on the Greek
word “ozein” (scent) [4]. Ozone is produced from electric generators when an electrical
discharge (a spark) splits an oxygen molecule into two oxygen atoms, and then the unstable
ozone molecule is formed according to the reaction O + O
. According to the balanced
equation 2O
, where ozone quickly decomposes into O
(t½ = 20–30 min), requires
that it must be produced in the location where it is used. When it decomposes, O
acts as an
oxidant with release of free radicals. Being an oxidant, ozone has antimicrobial properties
against bacteria, viruses and protozoa [5], and it was first used for general disinfection of
water. Later, ozone was used in food hygiene, fish farming, air purification, hot tubes, and in
some areas of medicine, especially dentistry [6].
Ozone leads to the destruction of both bacteria and viruses [7, 8], by interfering with
metabolism, most likely by inhibiting enzymes. Some ozone breaks through the bacterial cell
membrane, and this leads to cell death. Ozone destroys viruses by diffusing through the
protein coat into the nucleic acid core, resulting in damage to the viral RNA. At higher
concentrations, ozone destroys the capsid by oxidation [9].
Ozone is toxic to humans at higher concentrations, especially to the lungs. The
Norwegian Labour Inspection Authority accepts an 8-h working day average exposure of 0.1
ppm, and this can be exceeded by 200% for periods of 15 min [10]. This limits the use of
ozone gas as a disinfection agent in surroundings with human activity. However, the gas can
be dissolved in tap water for hand washing, and most of the gas then passes in the water
through the outlet of the sink.
Hand hygiene is one of the most important tools available for reducing the spread of
transient microbial pathogens in healthcare and community settings. In the era of multidrug-
resistant bacteria and frequent outbreaks of viral gastroenteritis, hand disinfection has become
an even more essential tool in reducing the spread of microorganisms both in health
institutions and in general society [11]. The main disinfection methods used are handwashing
with soap and alcohol-based solutions [12]. However, both of these are associated with
adverse skin reactions like dryness and dermatitis among sensitive individuals, and
compliance with hygiene recommendations is also variable among health professionals [13,
14]. Among nurses, 25–55% report adverse skin reactions related to hand hygiene procedures
[15]. Meanwhile, the effect of alcohol disinfection on viruses like norovirus and rotavirus is
unclear, and it has little effect on spores of the bacterium Clostridium difficile [14]. Ozone
gas in higher concentration has also shown to be an effective alternative for sanitizing rooms
[16, 17].
There have been few studies on the potential of using ozonized water as a simple,
cheap and skin-friendly alternative to standard hand disinfection with alcohol. Appelgrein et
al. found ozone to be inferior in effect to propanolol-based hand rubs [18]. Isosu et al. found
ozonized water combined with benzalkonium chloride and alcohol to be an effective
alternative to traditional surgical washing procedures [19]. In a unpublished study where ATP
was used as an indication of the efficacy of hand disinfection, Liceaga et al. found that ozone
combined with soap removed 97.3% of ATP from hands, and noted the lack of studies
regarding ozone and hand sanitation [20]. In a recent study, Nakamura et al. found
a 3
log10 cfu reduction was achieved by washing hands with ozonated water or antimicrobial
soap and water. However, ozonated water was not significantly superior to non-antimicrobial
soap and water [21].
The aim of this study was to compare the effect on Escherichia coli-contaminated
hands of ozonized water with standard alcohol-based hand disinfection using a modified
European Standard procedure (EN 1500:2013) [22].
Materials and methods
The test procedure was modified from European Standard EN 1500:2013, which specifies a
method for simulating practical conditions for establishing whether a product for hygienic
hand sanitation reduces the release of transient microbes after use on the artificially-
contaminated hands of volunteers. For testing one product at a time, a crossover design was
used. The 30 test persons were all nursing students (26 women/4 men) at the end of their
second year of study (average age 23 years). None of the students had visible signs of
dermatitis on their hands during the study days. On day one, the 30 students were divided
randomly into two equal groups of 15, one using ozonized water 0.8 ppm and the other 4.0
ppm. Six days later the same students used the reference disinfectant, ethanol supplemented
with propan-2-ol (Antibac, 85% with glycerol, The test organism was non-
pathogenic E. coli (ATCC® 25922), as recommended in the standard procedure. This
bacterial strain is often used as a reference strain in microbial research.
E. coli was cultured for 18–24 h at 36 °C on Tryptic Soy Agar plates (Thermo Fisher
Scientific, USA). A single colony was then inoculated into 10 mL Tryptic Soy Broth (TSB),
and cultivated for 18–24 h. The 10-mL bacterial solution was then used to inoculate 1 L TSB
before further cultivation for 18–24 h. The final concentration of cultured E. coli was
estimated as >10
colony-forming units (CFU)/mL. The 1 L solution was divided into two
500-mL glass containers.
The test subjects prepared their hands by washing for 1 min with soft soap and
lukewarm tap water to remove natural transients. The hands were then dried with paper
towels, and immersed up to the mid-metacarpals for 5 s, one hand in each of the glass vessels
containing bacterial solution. Hands were air-dried in a horizontal position with the fingers
spread and rotating for 3 min. Immediately after drying, the fingertips were rubbed on the
base of a Petri dish containing 10 mL of TSB using separate Petri dishes for each hand.
Without further delay, the test subject then performed the hygienic hand rub procedure, using
ozonized water or the reference hand rub (3 mL of 85% Antibac) according to information
provided by the manufacturer. The hygienic hand rubbing time for both ozone water and
Antibac was 30 s. After cleaning, the fingertips were dried and rubbed on the base of new
Petri dishes containing 10 mL of TSB. Immediately after performing the tests, 1 mL of pre-
or postvalue sampling fluid was transferred into Eppendorf tubes (Thermo Fisher Scientific),
and brought to the laboratory in a cooling bag. Within 24 h, 10 µL of the pre-or postvalue
samples were spread on two parallel MacConkey agar plates (Mac3, Thermo Fisher
Scientific) and incubated for 18–24 h at 36 ± 1 °C before counting the number of CFU. The
pre-test value was the number of CFU sampled from the left or right hand prior to hand
sanitization treatment, and the post-test value was the number of CFU after treatment.
Calculation of CFU/mL was performed by multiplying the arithmetic mean of the plate CFU
counts for each hand by the dilution factor of 100. For both reference and test procedures, the
counts from the right or left hand of each subject were averaged separately to obtain pre-
values and post-values. CFU counts >300 per 10 µL were not counted and were noted as
>30,000 CFU/mL.
Ozonized water was produced by two separate generators, a Water Ozonator
CYS300C from Cleanzone delivering 0.8 ppm in tap water, and a BioSure CSS from Ozone
Scandinavia delivering 4.0 ppm in tap water. For measuring the ozone gas concentration in
surrounding air, three different sensors were used (EcoZone Monitor, EZ-1X, Eco Sensors,
Inc. type A-21ZX and Murco Portable Ozone Detectorand), and we also measured the level
of ozone in the tap water. The tap water was regular domestic water of approximately 20°C
from the local water reservoir in Førde, Norway. Water here is filtered through a layer of
marble sand, and then disinfected with chlorine and UV light. It has a pH of 7.8–8.3 [23]. The
tap water-flow were different. For the ozone 0.8 ppm generator the flow was about 8 L/min,
while the 4.0 ppm the BioSure CSS delivered only 2 L/min.
The students were informed in a lesson about the study and invited to participate. The
resulting participants gave their written consent. The study was approved by the Regional
Committee for Medical Research Ethics and the Norwegian Data Inspectorate (reference
number: 2017/943).
Statistical analysis
Categorical data is presented with numbers and percentages. The raw data (CFU/mL) after
using ozonized water and alcohol disinfection are displayed within figures. CFU/mL values
from both hands combined after using ozone water and alcohol disinfection are presented as
the average values along with standard deviations (SD), and also as the medians with ranges.
CFU/mL scores from each hand are presented as average values. The Wilcoxon signed-rank
test was used to test for differences in CFU/mL values after using ozone water or alcohol
disinfection. The Mann-Whitney U-test was used to test if CFU/mL was different using
ozone water with 4,0 ppm versus 0,8 ppm. A P-value < 0.05 was considered significant. The
analysis was conducted using SPSS software version 24, and figures were prepared using
GraphPad Prism version 8.
All 30 participants completed the study. Eight of the students (27%) reported varying degrees
of previous skin problems connected to handwashing and disinfection.
In connection to the experiment, 20% of participants reported some adverse skin
effects (burning/dryness) from using the alcohol disinfection method, but continued the
procedure as planned. Their post-CFU counts showed no special pattern. None reported
adverse sensations using ozonized water. Half of the participants reported that they felt their
hands became smoother/softer after ozone use, and after the experiment the majority (77%)
said they would prefer ozonized water disinfection if the two methods were equal in
antimicrobial effect.
Table I summarizes the bacteriological results. From all 60 hands (30 participants,
each with left and right hand) the pre-tests gave a CFU count >30 000 /mL. The average post-
test value for both hands combined in CFU/mL after using ozonized water was 1017 (SD,
1391), and for regular alcohol hand disinfection was 2337 (SD, 4664). The median post-test
value (in CFU/mL) after using ozonized water was 500 (range, 6700), and for regular alcohol
hand disinfection was 250 (range, 16 000), P=0.713. Where disinfection used the higher
ozone concentration (4.0 ppm), values were not statistically different in CFU/mL compared
to those for the lower concentration (0.8 ppm) (P=0.142).
More hands (n = 26) showed zero post-value CFU-counts from fingers using alcohol
versus ozone (n = 10) (Figure 1). There was greater individual variation in the CFU-counts
for alcohol (0–12,500) compared with ozone (0–4800), especially for the left hand. Skin
symptoms from alcohol disinfection earlier or during the study was not correlated with higher
CFU-counts in post-tests.
The measured level of ozone gas in the air around the face-level of the students never
exceeded 0.01 ppm (one-tenth of the exposure limit of 0.1 ppm for 8 h). However, when
asked afterwards, 77% of the students reported they had noticed the characteristic smell of
ozone gas, which also represent an extra security factor in connection with ozone use.
This study indicated that ozonized water on average eradicates E. coli from artificially-
contaminated fingers as effectively as 85% alcohol. The variation in results between
individuals, and between the two hands of the same individual, was higher for alcohol
disinfection than disinfection using ozonized water. The concentration of ozone gas in the
surrounding air was low, and there were no adverse skin reactions with the ozone method.
The ozone method was preferred by most of the nursing students. The ozone hand
disinfection method is simple, cheap and leaves no residual waste, and when dissolved in
water ozone also seems to be safe.
Our conclusion is that ozonized water could be an alternative to traditional fluid hand
disinfectants with alcohol, for example in institutions. Appelgrein et al. also found an effect
of ozone, but this was inferior to alcohol [19]. In their study with 4.0 ppm ozone, they used a
lower concentration of alcohol (60%), but the amount was double (3+3 ml) and the exposure
time was longer (3 min.), and also on one of the hands they used a delayed 3 hour method. It
is therefore not comparable in all the details to our study.
The seemingly better effect of 0.8 ppm ozone compared to 4.0 ppm was surprising,
but both the different technical design of the generators and especially the different water
flow could be possible explanations for this observation. Under ideal circumstances we
should have used the same generator producing different concentrations, but CYS 300C can
only deliver 0.8 ppm at maximum output.
Other studies have shown that the presence of organic carbon in water can severely reduce
ozone effectiveness when used as a method to eradicate the bacterial load [24].
In the present study, we found differences in effect between the left hand and right
hand in CFU-counts post-disinfection with alcohol, but less difference with ozone. Fierera et
al. found significant heterogeneity in bacterial community composition between left and right
hands from the same individual depending on handedness, gender and time since last hand
washing [25]. We do not have data on the handedness of our participants. However, the
spreading of a sparse amount of alcohol disinfectant (3 ml) to all parts of both hands can be
more difficult, even under ideal circumstances, than the simpler procedure of just holding and
rubbing both hands under a greater volume of running tap water (8 L/min) containing ozone.
The inferior results for ozone 4.0 ppm when delivered in only 2 L/min of water could also
point in this direction.
Adverse skin reactions connected to hand hygiene are prevalent among health professionals
[12]. Among the participants in this study, 20% of the participant reported adverse skin
effects (burning/dryness) from using the alcohol disinfection method whereas none reported
these problems when using ozonized water. We find this to be an interesting observation. The
standard method for comparing hand disinfectants (EN 1500:2013) has been criticized for not
being in line with clinical practice, and for not testing microorganisms other than E. coli [26].
To be more in line with the present advised practice in healthcare institutions, we modified
the Standard by using only 3 mL/30 s for alcohol hand disinfection, and used a higher
concentration of alcohol (Antibac 85%) than the 60% in the Standard.
This study was performed in optimal circumstances with well-informed and
professional healthcare students knowing the background and correct technique for hand
disinfection. The hand disinfection with alcohol was administrated and observed by a nurse
specializing in hygiene. The effect of hand wash/hand disinfection on contaminated hands
can therefore be expected to be poorer in general public health circumstances, and especially
among children. The broad-spectrum antimicrobial effect of ozone, including naked viruses
and protozoa, could represent an important potential in public health efforts aimed at
communicable diseases. We have not found any publication regarding the potential for
developing bacterial resistance to ozone. This study confirms that ozonized water possesses
antimicrobial properties in line with alcohol, and that it could have a place in effective hand
hygiene protocols, especially targeted at individuals with skin problems. For some, this
becomes a major problem resulting in sick leave and, eventually, working disability. This was
the situation for one of the authors of this study (DEL) before he obtained permission to use
ozone in his preoperative hand disinfection procedure.
There are few studies about the effect of ozone as an antimicrobial agent in human
medicine. We need further studies comparing regular hand washing with soap vs. ozonized
water, and on the use of ozonized water as primary prevention of prevalent infections in
schools and kindergartens. Research should also focus on the possibility of using ozone as an
alternative to soap washing and alcohol disinfection for persons with contact dermatitis.
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We thank the nurse students for their participation and assistance in performing this study,
and two bioengineers at the Microbiological Department of Førde Hospital, Torill Aarø and
Torunn Ytreland, for their excellent assistance.
The study had a small internal financial grant from Helse Førde Medical Trust, and no
external grants.
Potential conflicts of interest: One of the authors (DEL) has a small ownership in a firm that
manufactures ozone generators. For the other authors: Nothing to declare.
Table I. Data for Escherichia coli cultivation CFU/mL (colony-forming units/mL). Samples
were taken from left and right hands treated with a standard solution of
non-pathogenic E.
coli (ATCC® 25922), then disinfected with ozonized tap water (ozone) or alcohol rub
(alcohol; Antibac, 85% v/v). All pre-tests had CFU > 30 000/mL.
Hands Ozone
(0.8 and 4.0
ppm combined)
(0.8 ppm) Ozone
(4.0 ppm) Alcohol
Both hands,
mean (SD) 1017 (1391) 600 (643) 1433 (1795) 2337 (4664)
Both hands,
median (range) 500 (6700) 300 (2500) 700 (6600) 250 (16000)
Right hand,
mean (SD) 550 (942) 240 (232) 860 (1256) 797 (2147)
Right hand,
median (range) 300 (4800) 200 (800) 400 (4800) 100 (10500)
Left hand, mean
(SD) 467 (574) 360 (526) 573 (617) 1540 (3294)
Left hand,
median (range) 250 (2000) 200 (2000) 300 (1800) 100 (12500)
N = 30 in all analyses. SD: Standard deviation.
Figure Legends
Figure 1a: Individual distribution of CFU-counts/mL after disinfection of hands with 3 mL of
85% alcohol for 30 s, and fig. 1b: Individual distribution of CFU-counts/mL after disinfection
of hands with ozonized water for 30 s.
Illustration 1. Equipment (generators) used for ozonizion of tap water: BioSure CSS and
BioSure CSS
in water
8 ppm
Energy Usage
60 watts
Size (in.)
17.1 x 12.9 x 6.9
7.5 kg
... In two earlier studies, we concluded that a water-based hand rub (WBHR), using ozonized tap water or soap water, might be more effective than the ABHR practice to remove transient Escherichia coli from artificially contaminated hands. This was also the preferred method among the nurse students who composed the study cohort [12,13]. ...
... The importance of education and training skills to perform ABHR correctly is well known from the literature [20,21]. We conducted two earlier studies with the ABHR procedures and found similar results among nurse students [12,13]. It has been demonstrated in a study that up to 86% of test subjects in a real world setting use only small doses of alcohol disinfectant, if not instructed otherwise, as low as approximately 0.75 mL [22]. ...
Full-text available
Efficient hand hygiene is essential for preventing the transmission of microorganisms. Alcohol-based hand rub (ABHR) is a recommended method. We compared health personnel (skilled nurse students) with random adults to study the effect of an ABHR procedure. A water-based hand rub (WBHR) procedure, using running tap water and a hand-drying machine, was also investigated. The study included 27 nurse students and 26 random adults. Hands were contaminated with Escherichia coli, and concentrations of colony forming units (CFU/mL) were determined before and after ABHR or WBHR. Concentrations after ABHR were 1537 CFU/mL (nurse students) and 13,508 CFU/mL (random adults) (p < 0.001). One-third of participants reported skin irritation from daily ABHR. Concentrations after WBHR were 41 CFU/mL (nurse students) and 115 CFU/mL (random adults) (p < 0.011). The majority of participants (88.5%) preferred the WBHR method. Results from 50 air samples from filtered air from the hand dryer outlet showed no CFU in 47 samples. A significant difference between the two groups was shown for the ABHR method, indicating that training skills are important for efficient hand hygiene. Surprisingly, the WBHR method seemed to have a significant effect in largely removing transient bacteria from hands.
... The use of biocidal agents with high antimicrobial activity and low chances of generating microbial resistance, which have a short half-life and decompose into non-toxic molecules, is an effective alternative as a measure of disease control and propagation in these highly disseminated environments. Ozone (O 3 ) is among the most powerful oxidants known, with an oxidative potential approximately twice the oxidizing potential of chlorine 27 . The antimicrobial capacity of O 3 includes not only bacteria, but fungi, viruses and protozoa 28,29 . ...
... Although specific evaluation studies for disinfection chambers and their direct use by people were not found, these studies show that the use of questionnaires to understand the perceptions and acceptance of individuals in relation to the development of new technologies is important in coping with the challenges involved, especially when it comes to the analysis of a new biocidal agent applied for the first time in this case. Within this context, given the results obtained regarding the absence of discomfort when using the disinfection chamber of this study, this data confirms the reduction of sensations generated in relation to O 3 in its gas form, when dissolved in water 27,58,59 . Furthermore, this feat may be related to the concentration used, not exceeding sensory limits for the participants. ...
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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.
... Different respiratory viruses, including SARS have been modelled for fomite-mediated transmission self-inoculation mechanism could have a profound effect as a route of microbial transmission. HCWs have a hi irritation, perhaps because of the need for frequent hand sanitization in hospitals (8,14).Studies have revealed that healthcare workers' hands are highly contaminated with bacteria maintenance of healthy skin is crucia particular, the preservation of lipids, fatty acids and resident microbial flora is important (8,15). More pertinently, continuous use of alcohol disinfection has been linked to unfavorable skin consequences as itchiness, burning, and dryness (8,16 effects is because alcohol disinfectants, which are by definition germicidal, can react with the intercellular lipids of the stratum corneum, causing lipid solubilization, fluidization, and extraction. ...
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There is a frangible balance between skin health and disease. Fomite interaction is a source of microbiome heterogeneity, in regions which have a relatively stable commensal microbiome, and in communion with skin fragility can sway the balance between the commensal and pathogenic microorganisms in favour of the pathogenic microbes. With the prolonged use of alcohol-based hand sanitizers in the current context of COVID 19, causing skin irritation and increasing the chances of transient pathogenic microbes colonizing the hand/palmar surfaces. Also given that the face is on average the most touched region among the hair, face, neck and shoulders (HFNS) regions both in terms of frequency and duration. This could facilitate the increase of facial dermatological lesions specifically and dermatological and mucosal infections generally. More worryingly, this increase microbial transmission could include SARS-COV2 and hence increase COVID 19 infections even though the fomite route of transmission of COVID 19 is reported to be low.
... Indeed, in the scientific literature, there are reports of its use in treating wounds and even for human consumption as a drink (Leon et al. 2022;Hayakumo et al. 2013). Breidablik et al. (2019) showed that ozonated tap water (0.8 or 4 ppm O 3 ) had antimicrobial properties and could be an alternative to traditional alcohol-based hand disinfectants for nursing students, especially valuable for persons with contact dermatitis. In a short report (Breidablik et al. 2020), the same researchers showed that ozonated water together with a regular soap-and-water hand wash may be more effective than alcohol for the removal of bacteria from artificially contaminated hands. ...
PurposeThe walls, ceiling, and floor of a surgical environment, as well as the surfaces used in this place, must be submitted to a disinfection protocol to minimize nosocomial infections. Health regulations recommend two stages; the first is characterized by cleaning procedures, mainly using an enzymatic detergent, and the second is use of a disinfection agent. Ozone is a natural substance that has a relevant oxidative property for inactivating microorganisms and has emerged as an interesting agent in the hospital environment. Compared with conventional chemical products for disinfection, ozonated water has advantages such as a lack of storage control, disposal, and handling safety. The objective of this study was to use ozonated water as a disinfectant agent on a hospital metal surface, in comparison with 70% alcohol.Methods The degree of disinfection of the metal surface was quantitatively analyzed with use of an instrument by bioluminescence for a disinfection test.ResultsQualitative terms indicated gram-positive cocci microorganisms and yeasts, suggesting that bacteria and fungi from the environment were identified. After the use of ozonated water as a disinfectant, the quantitative analysis indicated values below 100 RLU, showing evidence of a surface suitable for use in surgical procedures.Conclusion The use of ozonated water as a disinfectant agent for a metal surface in a hospital environment showed more effectiveness than 70% alcohol. Thus, ozonated water is a promising agent for disinfecting surfaces in surgical environments.
... In a searching for less irritating skin antimicrobial compounds, researchers performed an antiseptic test in accordance with the modified EN 1500 [24] with the use of ozonized tap water [32]. This comparative study included 30 nursing students whose hands were artificially contaminated with E. coli ATCC 25922, then sanitized with ozonized tap water (0.8 or 4 ppm) or 3 mL of standard alcohol-based rub (Antibac 85%). ...
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Disinfectants and antiseptics are important weapons to reduce the number of microorganisms and thus to limit the number of infections. Different methods of antimicrobial activity testing, often not standardised, without appropriate controls and not validated are applied. To address these issues, several European Standards (EN) have been developed, describing the test methods to determine whether chemical disinfectants or antiseptic products have appropriate bactericidal, sporicidal, mycobactericidal or tuberculocidal activity; fungicidal or yeasticidal activity; or virucidal activity. In this narrative review, the 17 EN concerning evaluation of the above-mentioned antimicrobial activity of preparations dedicated to the medical area are briefly reviewed, together with recent publications on this topic. Suspension and carrier tests have been performed in clean and dirty conditions simulating the medical area. In addition, a wide range of applications of these standards has been presented in the research of biocides for hand antisepsis, surfaces disinfection, including airborne disinfection as well as medical device and medical textile disinfection. The role of normative documents in the investigation of antimicrobial activity of disinfectants and antiseptics to limit infections has been underestimated. This narrative review aims to persuade researchers to conduct antimicrobial activity testing in line with validated EN and highlights an existing gap in ongoing research. It also aims to raise awareness of the wide range of biocidal activity tests with standardised methods in medical area. We also pay attention to the recently developed European Pharmacopoeia monography concerning the testing of bactericidal and fungicidal activity of antiseptics classified as medicinal products.
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 & 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.
Ozonated water is a potential alternative approach for hand antisepsis. While short-term studies report no immediate adverse effects to human skin or health, there are no published studies of long-term exposure. A retrospective cross-sectional mixed methods study was used to investigate the risk of adverse clinical health effects from chronic intermittent ozonated water exposure at 0.6 µg/ml in the United States. Thirty subjects with long-term use of a kitchen sink faucet that produced ozonated water on command provided quantitative measures of exposure and the prevalence of related adverse skin, pulmonary, gastrointestinal, and other health consequences. Participants averaged 91.6 (range 4–420) minutes of exposure per week over an average of 143.4 (range 30.4–460.4) weeks of exposure. Ozonated water was used for a variety of tasks, including hand hygiene, rinsing of produce and utensils, and family food preparation. Subjects indicated on a variety of measures that there were no individual or family health effects, including but not limited to skin irritation and thickening, respiratory, and gastrointestinal symptoms. In this study, chronic recurrent exposure to ozonated water had no reported adverse health consequences after nearly 3 years of daily exposure.
The exposure of healthcare workers to antineoplastic drugs in hospitals has been recognized to be harmful. To minimize the risk of exposure, the removal of these drugs from work environments, such as compounding facilities, has been recommended. In our previous paper, the degradation and inactivation efficacy of ozone water, which is being introduced into Japanese hospitals as a chemical decontamination agent, was reported for its effects on typical antineoplastic drugs (gemcitabine, irinotecan, paclitaxel). This article aims to further investigate the efficacy of ozone water for eight antineoplastic drugs to clarify its application limitations. A small amount (medicinal ingredient: typically ca. 1.5 μmol) of formulation containing 5-fluorouracil, pemetrexed, cisplatin, oxaliplatin, cyclophosphamide, ifosfamide, doxorubicin, or docetaxel was mixed with 50 mL of ozone water (~8 mg/L), and the resulting solutions were analyzed by high-performance liquid chromatography over time to observe the degradation. Consequently, the ozonation was overall effective for the degradation of the drugs, however this varied depending on the chemical structures of the drugs and additives in their formulations. In addition, after the parent drugs were completely degraded by the ozonation, the degradation mixtures were subjected to 1H nuclear magnetic resonance spectroscopy and evaluated for mutagenicity against Salmonella typhimurium strains and cytotoxicity against human cancer cells. The degradation mixtures of cisplatin and ifosfamide were mutagenic while those of the other drugs were non-mutagenic. Further, the ozonation resulted in clear decreases of cytotoxicity for 5-fluorouracil, oxaliplatin, and doxorubicin, but increases of cytotoxicity for pemetrexed, cisplatin, cyclophosphamide, and ifosfamide. These results suggest that the ozone water should be restrictedly used according to the situation of contamination in clinical settings because the ozonation enhances toxicity depending on the drug even if degradation is achieved.
O3 and free chlorine play significant roles in disinfection and organic degradation. There are numerous reports about their mixed-use, yet detection of the residual concentrations is not easily accomplished, whilst the interactions between them remain unclear. Herein, we develop a detection method using a boron-doped diamond (BDD) electrode to achieve the simultaneous determination of O3 and free chlorine, which benefits from the unique property of the wide potential window of BDD electrodes. It is indicated that O3 can always be accurately determined at 0.35 V vs. Ag/AgCl in an acidic solution (pH = 4-5), whether or not free chlorine is present in the solution, whereas free chlorine can be precisely monitored at -0.78 V vs. Ag/AgCl only after the O3 is completely depleted. Furthermore, in a basic solution (pH = 9-10), the reduction peak of O3 at 0.57 V vs. Ag/AgCl promptly disappears accompanied by a decrease in the peak current of free chlorine at 1.41 V. All the phenomena observed in the acidic and basic solutions are concurrently confirmed in a quasi-neutral solution. Based on these complementary measurements, a mechanism is proposed, in which the O3 reduction results in partial oxidation of the BDD surface, hindering the reduction of free chlorine in the acidic mixture; whereas O3 reacts quickly with free chlorine in the basic solution, which causes the co-consumption of both of them. It is hoped these results will give us a guide as to how better utilize mixtures and more precisely simultaneously determine O3 and free chlorine in the mixture.
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Aims We investigated the effectiveness of ozone (aqueous and gaseous) treatment as an alternative sanitizing technology to common conventional disinfectants in reducing the microbial contamination of both water and air. Methods Ozone was added for 20 minutes to a well-defined volume of water and air by the system named "Ozonomatic®". The effectiveness of ozonation was determined by counting CFU/ m3 or ml of bacteria present in samples of air or water collected before (T0) and after (T1) the addition of ozone and comparing the microbial load of different bacteria present in ozonized and nonozonized samples. Results When the ozonisation equipment was located at 30 cm from the surface of the water in the bath tub in which the bacteria investigated were inoculated, the treatment was able to reduce the total microbial load present in the aerosol by 70.4% at a temperature of 36°C for 48 hours. Conversely, at 22°C for 5 days, only a modest decrease (9.1%) was observed. Escherichia coli and Pseudomonas aeruginosa were completely eliminated. A 93.9% reduction was observed for Staphylococcus aureus, followed by Streptococcus faecalis (25.9%). The addition of ozone to water was able to almost eliminate Staphylococcus aureus (98.9% reduction) and also to exert a strong impact on Legionella pneumophila (87.5% reduction). Streptococcus faecalis and Pseudomonas aeruginosa showed a decrease of 64.2% and 57.4%, respectively. Conversely, only a 26.4% reduction was observed for the bacterium Escherichia coli. This study showed that the addition of ozone in the air exerted a modest reduction on microbial load at 36°C, whereas no effect was observed at 22°C. Conclusions Aqueous and gaseous ozone treatments were effective against microbial contaminants, reducing the CFU of the microorganisms studied. These results confirm the efficacy of the ozone disinfection treatment of both water and air; particularly, it constitutes an extremely promising alternative, allowing the possibility to reuse contaminated water.
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Ozone is a strong oxidizing biocide that has broad-spectrum antimicrobial properties. The aim of the study was to compare the efficacy of ozone to a propanol-based hand rub for hand disinfection. Twenty subjects were enrolled in an in-vivo cross-over trial (prEN 12791). Subjects treated their hands with the reference procedure (propan-1-ol 60%) or with ozone (4 ppm). Post-wash bacterial counts were determined from one hand (immediate effect), and from the other hand that had been gloved for 3 h (delayed effect). The investigation indicated that ozone is inferior to propan-1-ol 60% hand rub for hand asepsis.
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Foams containing 62% ethanol are used for hand decontamination in many countries. A long drying time may reduce the compliance of healthcare workers in applying the recommended amount of foam. Therefore, we have investigated the correlation between the applied amount and drying time, and the bactericidal efficacy of ethanol foams. In a first part of tests, four foams (Alcare plus, Avagard Foam, Bode test foam, Purell Instant Hand Sanitizer) containing 62% ethanol, which is commonly used in U.S. hospitals, were applied to 14 volunteers in a total of seven variations, to measure drying times. In a second part of tests, the efficacy of the established amount of foam for a 30 s application time of two foams (Alcare plus, Purell Instant Hand Sanitizer) and water was compared to the EN 1500 standard of 2 x 3 mL applications of 2-propanol 60% (v/v), on hands artificially contaminated with Escherichia coli. Each application used a cross-over design against the reference alcohol with 15 volunteers. The mean weight of the applied foam varied between 1.78 and 3.09 g, and the mean duration to dryness was between 37 s and 103 s. The correlation between the amount of foam applied and time until hands felt dry was highly significant (p < 0.001; Pearson's correlation coefficient: 0.724; 95% confidence interval: 0.52-0.93). By linear correlation, 1.6 g gave an intercept of a 30 s application time. Application of 1.6 g of Purell Instant Hand Sanitizer (mean log10-reduction: 3.05 +/- 0.45) and Alcare plus (3.58 +/- 0.71) was significantly less effective than the reference disinfection (4.83 +/- 0.89 and 4.60 +/- 0.59, respectively; p < 0.001). Application of 1.6 g of water gave a mean log10-reduction of 2.39 +/- 0.57. When using 62% ethanol foams, the time required for dryness often exceeds the recommended 30 s. Therefore, only a small volume is likely to be applied in clinical practice. Small amounts, however, failed to meet the efficacy requirements of EN 1500 and were only somewhat more effective than water.
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To assess the prevalence and correlates of compliance and noncompliance with hand hygiene guidelines in hospital care. A systematic review of studies published before January 1, 2009, on observed or self-reported compliance rates. Articles on empirical studies written in English and conducted on general patient populations in industrialized countries were included. The results were grouped by type of healthcare worker before and after patient contact. Correlates contributing to compliance were grouped and listed. We included 96 empirical studies, the majority (n = 65) in intensive care units. In general, the study methods were not very robust and often ill reported. We found an overall median compliance rate of 40%. Unadjusted compliance rates were lower in intensive care units (30%-40%) than in other settings (50%-60%), lower among physicians (32%) than among nurses (48%), and before (21%) rather than after (47%) patient contact. The majority of the time, the situations that were associated with a lower compliance rate were those with a high activity level and/or those in which a physician was involved. The majority of the time, the situations that were associated with a higher compliance rate were those having to do with dirty tasks, the introduction of alcohol-based hand rub or gel, performance feedback, and accessibility of materials. A minority of studies (n = 12) have investigated the behavioral determinants of hand hygiene, of which only 7 report the use of a theoretical framework with inconclusive results. Noncompliance with hand hygiene guidelines is a universal problem, which calls for standardized measures for research and monitoring. Theoretical models from the behavioral sciences should be used internationally and should be adapted to better explain the complexities of hand hygiene.
Scott, D. B. McNair (University of Pennsylvania, Philadelphia) and E. C. Lesher. Effect of ozone on survival and permeability of Escherichia coli. J. Bacteriol. 85 567–576. 1963.—Escherichia coli cultures in the logarithmic phase or resting were treated with various concentrations of ozone in saline solution. Approximately 2 × 10⁷ molecules of ozone per bacterium killed 50% of the cells. Ozone caused leakage of cell content into the medium, and lysis of some cells. Low concentrations of ozone did not react with the glutathione within the cells, although reaction with glutathione in solution was immediate and stoichiometric. The effect on nucleic acid within the cells was to change the solubility and to cause the release of ultraviolet-absorbing material into the medium. Ozone attacked the ring structure of the base or the carbohydrate only when the substance was in the medium. Nucleic acids released into the medium were reabsorbed by cells which were not lysed. Viable cells resumed growth immediately, and grew at rates determined by the nutrients either added to the medium or which resulted from leakage and lysis of nonviable cells. It is postulated that the primary attack of ozone was on the cell wall or membrane of the bacteria, probably by reaction with the double bonds of lipids, and that leakage or lysis of the cells depended on the extent of that reaction.
We evaluated the bacterial removal effects of hand washing with ozonated water using the ASTM E1174 standard test method. Thirty healthy volunteers were assigned randomly to three groups: ozonated water, antimicrobial soap and water, and non-antimicrobial soap and water. A 3 log10CFU reduction was achieved by washing hands with ozonated water or antimicrobial soap and water. However, ozonated water was not significantly superior to non-antimicrobial soap and water. Ozonated water may remove bacteria from the hands to at least a similar extent as that by non-antimicrobial soap and water in the absence of visible dirt or body fluid contamination.
Background The Australian National Hand Hygiene Initiative (NHHI) is a major patient safety programme co-ordinated by Hand Hygiene Australia (HHA) and funded by the Australian Commission for Safety and Quality in Health Care. The annual costs of running this programme need to be understood to know the cost-effectiveness of a decision to sustain it as part of health services. Aim To estimate the annual health services cost of running the NHHI; the set-up costs are excluded. Methods A health services perspective was adopted for the costing and collected data from the 50 largest public hospitals in Australia that implemented the initiative, covering all states and territories. The costs of HHA, the costs to the state-level infection-prevention groups, the costs incurred by each acute hospital, and the costs for additional alcohol-based hand rub are all included. Findings The programme cost AU$5.56 million each year (US$5.76, £3.63 million). Most of the cost is incurred at the hospital level (65%) and arose from the extra time taken for auditing hand hygiene compliance and doing education and training. On average, each infection control practitioner spent 5 h per week on the NHHI, and the running cost per annum to their hospital was approximately AU$120,000 in 2012 (US$124,000, £78,000). Conclusion Good estimates of the total costs of this programme are fundamental to understanding the cost-effectiveness of implementing the NHHI. This paper reports transparent costing methods, and the results include their uncertainty.
Oxidation reaction rate parameters for molecular ozone (O3) and hydroxyl (HO) radicals with a variety of hydrophobic organic acids (HOAs) isolated from different geographic locations were determined from batch ozonation studies. Rate parameter values, obtained under equivalent dissolved organic carbon concentrations in both the presence and absence of non-NOM HO radical scavengers, varied as a function of NOM structure. First-order rate constants for O3 consumption (kO3) averaged 8.8×10−3 s−1, ranging from 3.9×10−3 s−1 for a groundwater HOA to >16×10−3 s−1 for river HOAs with large terrestrial carbon inputs. The average second-order rate constant (kHO,DOC) between HO radicals and NOM was 3.6×108 l (mol C)−1 s−1; a mass of 12 g C per mole C was used in all calculations. Specific ultraviolet absorbance (SUVA) at 254 or 280 nm of the HOAs correlated well (r>0.9) with O3 consumption rate parameters, implying that organic π-electrons strongly and selectively influence oxidative reactivity. HO radical reactions with NOM were less selective, although correlation between kHO,DOC and SUVA existed. Other physical–chemical properties of NOM, such as aromatic and aliphatic carbon content from 13C-NMR spectroscopy, proved less sensitive for predicting oxidation reactivity than SUVA. The implication of this study is that the structural nature of NOM varies temporally and spatially in a water source, and both the nature and amount of NOM will influence oxidation rates.