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Toilet Hygiene – Review and Research Needs

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The goal of good toilet hygiene is minimizing the potential for pathogen transmission. Control of odors is also socially important and believed to be a societal measure of cleanliness. Understanding the need for good cleaning and disinfecting is even more important today considering the potential spread of emerging pathogens such as SARS‐CoV‐2 virus. While the flush toilet was a major advancement in achieving these objectives, exposure to pathogens can occur from failure to clean and disinfectant areas within a restroom, as well as poor hand hygiene. The build‐up of biofilm within a toilet bowl/urinal including sink can result in the persistence of pathogens and odors. During flushing, pathogens can be ejected from the toilet bowl/urinal/sink and be transmitted by inhalation and contaminated fomites. Use of automatic toilet bowl cleaners can reduce the number of microorganisms ejected during a flush. Salmonella bacteria can colonize the underside of the rim of toilets and persist up to 50 days. Pathogenic enteric bacteria appear in greater numbers in the biofilm found in toilets than in the water. Source tracking of bacteria in homes has demonstrated that during cleaning enteric bacteria are transferred from the toilet to the bathroom sinks and that these same bacteria colonize cleaning tools used in the restroom. Quantitative microbial risk assessment has shown that significant risks exist from both aerosols and fomites in restrooms. Cleaning with soaps and detergents without the use of disinfectants in public restrooms may spread bacteria and viruses throughout the restroom. Odors in restrooms are largely controlled by ventilation and flushing volume in toilet/urinals. However, this results in increased energy and water usage. Contamination of both the air and surfaces in restrooms is well documented. Better quantification of the risks of infection are needed as this well help determine what interventions will minimize these risks.
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Toilet hygienereview and research needs
S.E. Abney
, K.R. Bright
, J. McKinney
, M. Khalid Ijaz
and C.P. Gerba
1 Department of Environmental Science, University of Arizona, Tucson, AZ, USA
2 Global Research and Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, USA
3 Department of Biology, Medgar Evers College of the City University of New York (CUNY), Brooklyn, NY, USA
aerosols, disinfectants, hygiene, odours,
pathogens, toilet.
Sarah E. Abney, Department of Environmental
Science, University of Arizona, 2959 Calle
Agua Nueva, Tucson, AZ 85745, USA.
2021/2769: received 29 December 2020,
revised 26 March 2021 and accepted 21 April
The goal of good toilet hygiene is minimizing the potential for pathogen
transmission. Control of odours is also socially important and believed to be a
societal measure of cleanliness. Understanding the need for good cleaning and
disinfecting is even more important today considering the potential spread of
emerging pathogens such as SARS-CoV-2 virus. While the flush toilet was a
major advancement in achieving these objectives, exposure to pathogens can
occur from failure to clean and disinfect areas within a restroom, as well as
poor hand hygiene. The build-up of biofilm within a toilet bowl/urinal
including sink can result in the persistence of pathogens and odours. During
flushing, pathogens can be ejected from the toilet bowl/urinal/sink and be
transmitted by inhalation and contaminated fomites. Use of automatic toilet
bowl cleaners can reduce the number of microorganisms ejected during a
flush. Salmonella bacteria can colonize the underside of the rim of toilets and
persist up to 50 days. Pathogenic enteric bacteria appear in greater numbers in
the biofilm found in toilets than in the water. Source tracking of bacteria in
homes has demonstrated that during cleaning enteric bacteria are transferred
from the toilet to the bathroom sinks and that these same bacteria colonize
cleaning tools used in the restroom. Quantitative microbial risk assessment has
shown that significant risks exist from both aerosols and fomites in restrooms.
Cleaning with soaps and detergents without the use of disinfectants in public
restrooms may spread bacteria and viruses throughout the restroom. Odours
in restrooms are largely controlled by ventilation and flushing volume in toilet/
urinals. However, this results in increased energy and water usage.
Contamination of both the air and surfaces in restrooms is well documented.
Better quantification of the risks of infection are needed as this will help
determine what interventions will minimize these risks.
The invention of the flush toilet over 150 years ago had a
major impact of toilet waste disposal within the household.
It eliminated the need to transport faecal wastes out of the
household by container handling. It also provided
plumbed water increasing the ease of hand washing (Aiello
et al. 2007). While the flush toilet was a major advance-
ment in achieving these objectives, exposure to pathogens
can still occur from failure to clean and disinfectant areas
within a restroom, as well as poor hand hygiene (Aiello
et al. 2007). Outbreaks of infectious agents-associated dis-
eases from toilets have been documented, largely from
improper cleaning and disinfection of restroom facilities
(Palmer et al. 1981; Rajaratnam et al. 1992). However, evi-
dence indicates that contamination of areas outside of the
toilet bowl/urinal can occur from aerosols generated from
flushing resulting in potential transmission by inhalation
and indirectly by fomite contamination (Gerba et al. 1975).
Fomite contamination can also occur directly by hand and
body contact with high touch/contact areas within a
restroom (Boone and Gerba 2007).
Journal of Applied Microbiology ©2021 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd
on behalf of Society for Applied Microbiology.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use,
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Journal of Applied Microbiology ISSN 1364-5072
This review summarizes the current state of knowledge
on microbial (pathogens) contamination and odours in
restrooms and approaches to better define these risks and
potential interventions to reduce these risks.
Occurrence and concentration of pathogens in
stools and urine
Many enteric pathogens are found in high titres in stools
and therefore in toilets after defecation, particularly during
episodes of acute diarrhoea. Some enteric pathogens such
as noroviruses are also found in high concentrations in
vomitus and can also thus contaminate toilets including
other areas indoor via a person vomiting. An infected per-
son can shed up to 10
colony forming units (CFU) of
Salmonella (Thomson 1954) and Shigella per stool (New-
som 1972). Persons infected with enteric viruses may shed
virus per gram of faeces (Table 1). During a
bout of acute diarrhoea, there is often splashing that may
contaminate the bowl sides and the recess under the toilet
bowl rim (Barker and Bloomfield 2000). After flushing, the
bacteria and viruses may be dispersed onto the external
parts of the toilet such as the seat, the handle, and to other
bathroom surfaces (Newsom 1972; Gerba et al. 1975). Bac-
teria generally do not survive well under conditions of des-
iccation; however, Newsom (1972) demonstrated the
survival of Salmonella on surfaces for up to 9 days, Escheri-
chia coli for up to 8 days, and Shigella for up to 5 days in
faeces dried onto toilet seats.
Bacteria and viruses may also be present in the urine
during infection (Table 2). Infectious viruses causing
insect-borne encephalitis have been documented, but other
viruses such as smallpox and adenoviruses, SARS-CoV-2
virus have also been detected in the urine (Sinclair et al.
2008; Sun et al. 2020). Variola major, the virus which
causes smallpox, is released for up to 19 days after infec-
tion at concentrations of 10
of urine (Sinclair
et al. 2008). In many infections, the greatest concentrations
are released during the first few days after the initial infec-
tion. Brucella abortus is excreted in concentrations as high
as 10
of urine for up to 12 weeks (Sinclair et al.
2008). SARS-CoV-2 concentrations are low, but infectious
virus detected in urine 12 days after onset of disease (Sun
et al. 2020). Significant amounts of pathogens can be
released in the urine considering people excrete from 700
to 2000 ml of urine per day (Crowdy 1984).
During cases of viral gastroenteritis, up to 10
particles have been detected per gram of stool. The aver-
age human adult stool weighs approximately 100 g (range
100400 g per day for an adult) and contains about 10
bacteria (Gerba et al. 1975), including 10
(Thomson 1954). Therefore, the toilet bowl could poten-
tially contain up to 10
virus particles (Barker and Jones
Many pathogens that are transmitted via the faecal
oral route are believed to have low infectivity such as Shi-
gella,Campylobacter,E. coli O157:H7, rotavirus, and nor-
ovirus (LeBaron et al. 1990). Ingestion of as low as 110
noroviruses are needed to cause an infection (Teunis
et al. 2008). The infectivity of Salmonella is generally
thought to be higher; however, depending upon the bac-
terial strain it can be as low as 10100 CFU (Hockin
et al. 1989; Barker and Bloomfield 2000).
Outbreaks associated with flush toilets
There have been reported outbreaks that provide evidence
to support the toilet as a source of infection for enteric
pathogens (Table 3). In a norovirus outbreak aboard an
Table 1 Concentration for pathogens and faecal bacteria in stools
Microorganism Concentration g
Coliforms 10
Haas et al. (2014)
Faecal coliforms 10
Haas et al. (2014)
Escherichia coli
Salmonella 10
Haas et al. (2014)
Campylobacter jujeni
E. coli 0157:H7
Shigella 10
Haas et al. (2014)
Enterovirus 10
Pepper et al. (2014)
Hepatitis A 10
Pepper et al. (2014)
Rotavirus 10
Pepper et al. (2014)
Norovirus 10
Pepper et al. (2014)
Adenovirus 10
Haas et al. (2014)
SARS-CoV-2 10
Xiao et al. (2020)
Cryptosporidium 10
Pepper et al. (2014)
Giardia 10
GWPP (2020)
Ascaris 10
Haas et al. (2014)
Table 2 Pathogens (infectious) excreted in the urine
Microorganism Reference
Coxiella burnetii Sinclair et al. (2008)
Viral encephalitis viruses Sinclair et al. (2008)
Nipah virus Sinclair et al. (2008)
Rabies virus Sinclair et al. (2008)
Smallpox virus Sinclair et al. (2008)
Cytomegalovirus Paduch (2007)
SARS-CoV Xu et al. (2005)
SARS-CoV-2 Sun et al. (2020)
Adenovirus Echavarria et al. (1998)
Measles (rubella) Gresser and Katz (1960); Paduch
Salmonella typhi; Salmonella
Crowdy 1984
Leptospira interorgans Crowdy 1984
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on behalf of Society for Applied Microbiology.
Toilet hygiene S.E. Abney et al.
international flight, the onset of illness was consistent
with a point-source outbreak but also suggested sec-
ondary transmission among passengers that subsequently
embarked on a cruise. The index cases had experienced
episodes of vomiting and diarrhoea in the airplane lava-
tories. Many of the passengers that became ill following
this flight were sitting near this block of bathrooms and
presumably were somewhat likely to have used these
facilities (Holmes and Simmons 2008). In a norovirus
outbreak among the cabin staff on an airplane, visibly
unsoiled toilets were reported to be the likely source of
infection for passengers (Hutson et al. 2002; Widdowson
et al. 2005). In a cruise ship outbreak of norovirus, the
use of a specific toilet contaminated by vomit during a
highly attended event was associated with increased odds
of illness (Chimonas et al. 2008). During a similar cruise
ship outbreak, the risk of gastroenteritis for those sharing
restroom facilities was twice that of those who had a pri-
vate bathroom. The risk of infection was also related to
the number of people sharing the communal restroom;
passengers sharing restrooms with more than 60 people
had an attack rate twice that of passengers sharing
restrooms with 20 or fewer people (Ho et al. 1989).
In an outbreak of hepatitis A virus (HAV) within a
middle school, the use of a particular toilet for defecation
was linked to the source of infection. This toilet had been
used by the index case during a bout of diarrhoea
(Rajaratnam et al. 1992). In a similar outbreak in a pri-
mary school in Italy, the critical exposure of the school
children was deemed to have taken place in the boys’ toi-
let. The toilet had been contaminated by a child with an
HAV infection acquired via consuming infected clams
outside of the school. None of the primary school girls or
the secondary school children, all who used separate
toilets, were infected (Leoni et al. 1998). An outbreak of
SARS-CoV in an apartment building with improper
restroom ventilation was believed to be involved in its
spread via aerosols generated from toilet flushing
(McKinney et al. 2006).
The spread of enteric bacterial pathogens has also been
linked to toilets. In a Salmonella Typhimurium outbreak
in university students, contamination of toilets was
believed to be the cause of secondary cases (Palmer et al.
1981). Outbreaks of shigellosis in schools linked to faecal
material in and around toilets have also been reported
(Hutchison 1956). In a nosocomial (hospital) outbreak
caused by Shigella sonnei, sharing of a toilet with the
index patient was believed to be the most probable source
of infection (Korpela et al. 1995).
Non-enteric bacteria can also potentially be spread by
toilets. Giannini et al. (2009) reported that the use of
alcohol wipes on toilet seats resulted in a 50-fold reduc-
tion in MRSA infections in a children’s hospital. Genome
sequencing data suggested that two cases of Legionella
pneumophila in a hospital in France were aerosolization
and inhalation of the bacteria from toilets was the cause
as this was believed to be the only significant route of
exposure (Couturier et al. 2020).
Contamination of flush toilets by pathogens
During an outbreak of shigellosis, contamination of toilet
seats was observed following flushing of liquid faeces
containing greater than 10
CFU per g of S. sonnei. Shi-
gella sonnei was present on 11 of 34 toilet seats tested
(Hutchison 1956). In a hospital ward, faecal bacteria grew
on 27% of settle plates exposed near ward toilets, sug-
gesting aerosolization of the toilet water. Escherichia coli
was also isolated from flush handles, toilet seats, and the
underside of toilet lids (Newsom 1972). Similar to the
results found by other researchers (Barker and Bloomfield
2000; Barker and Jones 2005), the number of bacteria in
the toilet was reduced by 2-log
by a single flush (New-
som 1972).
Barker and Bloomfield (2000) found Salmonella enteri-
tidis in the homes of four recovering Salmonellosis
patients in persistent biofilms under the rim of the toilet
bowl and in the scaly biofilm layer in the toilet bowl just
below the water line. Salmonella was not isolated from
the outside of the toilet bowl. In all cases, the serotype of
the bacteria isolated from the environment was identical
to that isolated from the patient. In all four homes, toilet
cleaning products were used on a daily to weekly basis.
Despite this, Salmonella bacteria were isolated from the
toilet for weeks, particularly from the biofilms. In one
home, S. enteritidis was found 4 weeks after the patient’s
diarrhoea had ceased. Pitts et al. (1998) have found
Table 3 Outbreaks associated with toilets
Source loca-
tion Reference
Norovirus Airplane Hutson et al. (2002); Widdowson
et al. (2005)
Cruise ship Ho et al. (1989)
Hepatitis A virus Primary
Leoni et al. (1998)
SARS-Cov Apartment
McKinney et al. (2006)
SARS-CoV-2 Hospital Ding et al. (2021)
Salmonella University Palmer et al. (1981)
Shigella Hospital Korpela et al. (1995)
MRSA Children’s
Giannini et al. (2009)
Hospital Couturier et al. (2020)
Journal of Applied Microbiology ©2021 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd
on behalf of Society for Applied Microbiology.
S.E. Abney et al.Toilet hygiene
biofilms in the toilet bowl below the water line measuring
up to 20 lm thick.
Contamination of flush toilets by use of bidet
Iyo et al. (2016) found Pseudomonas aeruginosa on 2% of
bidet toilets in a restroom on a university campus.
Warm-water tanks used for bidet toilets also showed a
decreased concentration of residual chlorine and thereby
an increase in heterotrophic and viable bacteria concen-
trations. Bacterial colonization of bidet toilets in hospitals
was found in 87% of bidet nozzle surfaces and 94% of
spray waterswhere Pseudomonas spp. were isolated
from 11 nozzle surfaces (57%) and 17 spray water
(88%) (Tsunoda et al. 2019). In a university affiliated
hospital, 34% (n=10) of bidet nozzles contained iso-
lated of Staphylococcus aureus. Methicillin resistant
reus was found on one bidet nozzle and one toilet seat
(Katsuse et al. 2017). Consistent users of bidet toilets
who are female report higher rates of abnormal vaginal E.
coli colonization and pre-term birth (Kim et al. 2019).
Aerosols produced by flush toilets
The potential for aerosolization of pathogens during toi-
let/urine flushing has received a lot of attention, espe-
cially in concerning emerging pathogens such as SARS,
Ebola, and Clostridium difficile. All the research indicates
that significant aerosolization can occur resulting in
potential transmission of pathogens by inhalation and via
fomite contamination (Johnson et al. 2013a). The degree
of aerosolization is dependent upon several factors listed
in Table 4. While large droplets settle out within a few
minutes, smaller may persist and continued to settle out
on surfaces for 90 min (Best et al. 2012; Knowlton et al.
2018). Residual levels of microorganisms may also remain
in the bowl after the initial flush, resulting in aerosoliza-
tion of bacteria after repeated flushes (Gerba et al. 1975;
Johnson et al. 2013a, 2017).
In a seeded toilet experiment (Barker and Bloomfield
2000), Salmonella could be isolated from the air, the toi-
let seat and lid following flushing of the toilet. In addi-
tion, the bacteria were released and could be found in
subsequent flushing aerosols, but in incrementally
decreasing numbers. After 6 days, the bacteria were no
longer found in the water in the toilet bowl. Nevertheless,
Salmonella was isolated from the biofilm below the water
line in the bowl for up to 50 days (Barker and Bloom-
field 2000). Barker and Jones (2005) observed similar
results for environmental contamination caused by flush-
ing a toilet seeded with Serratia marcescens and MS2 bac-
teriophage. The toilet water after flushing was reduced by
approximately 2-log
of Serratia after 60 min. Similarly,
bacterial counts in the air decreased from approximately
1300 to 500 and 128 CFU per m
after subsequent toilet
flushing. The bacterial contamination of external surfaces
was greatest in areas closest to the seeded toilet bowl
(i.e., the toilet seat).
Barker and Jones (2005) concluded that both the bac-
teria attached to the sidewalls of toilet bowl and those in
the water contribute to the formation of aerosols. The
bacterial numbers on the sidewalls and under the toilet
bowl rim were not significantly decreased by multiple
flushing and thus were probably the reservoir for contin-
uing residual contamination of the toilet bowl water.
Also, closing the toilet lid did little to prevent the release
of bacteria into the air. In a similar study, closing the toi-
let lid was also found to be ineffective at reducing bacte-
rial air counts (Bound and Atkinson 1966).
Darlow and Bale (1959) demonstrated that toilet water
artificially contaminated with Chromobacterium prodigio-
sum produced a widely disseminated and persistent aero-
sol after flushing. The aerosol was not prevented by weak
disinfectants or by closing the toilet lid during flushing.
Gerba et al. (1975) found that large numbers of seeded
bacteria and viruses remained in the toilet bowl following
flushing and even continual flushing could not entirely
remove them. In addition, both E. coli and MS2 bacterio-
phage were detected in droplets generated by flushing.
Aerosols were found to persist for at least 12 min and
could disseminate the microorganisms to surfaces
throughout the bathroom. The particles in these aerosols
were a size capable of being inhaled and of reaching the
lower respiratory tract.
Gerba et al. (1975) found that bacteria and viruses
seeded into the toilet bowl before flushing were ejected
from the bowl during flushing and settled on surfaces
throughout the restroom for up to 2 h. The number
ejected was directly related to the number in the bowl.
Aerosolized droplets derived from the toilet bowl are gen-
erated even when the toilet bowl is covered and can lead
to accumulation of aerosolized particles over time
Table 4 Factors that influence the aerosolization of microbes from
toilet flushing
Design of toilet
Amount of water in bowl
Waste (and type) in the bowl
Water pressure
Automatic toilet bowl cleaner
Chlorine in the tap water
Volume of water used in a flush
Lid down
Journal of Applied Microbiology ©2021 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd
on behalf of Society for Applied Microbiology.
Toilet hygiene S.E. Abney et al.
(Aithinne et al. 2019; Schreck et al. 2021). Modern flush
toilets generate significant amounts of aerosols less than
2lm diameter (95%) and fomite droplets greater than
5lm(>99%) (Johnson et al. 2013b).
Air quality in hospital wards are largely regulated
through mixed ventilation systems, however in the case of
an outbreak the use of displaced ventilation systems
achieves better microbial air quality when not influenced
by the proximity of restroom exhaust vents (Yin et al.
2009). Verani et al. (2014) detected adenoviruses in 67% of
air samples collected from the restrooms in offices and
55% in air from hospitals. Toque teno virus was present in
1518% of the air samples collected in these environments.
Transmission of SAR-CoV-2 and norovirus is influenced
by airflow direction produced by air-conditioning units in
restaurants and classrooms, respectively (Zhang et al. 2017;
Lu et al. 2020). The finding of infectious SARS-CoV-2 in
urine has created speculation that urinal flushing could be
involved in the transmission of this virus (Sun et al. 2020).
In studying droplets generated by urinal flushing Wang
et al. (2020) found that droplet could reach a height to be
inhaled by the average adult, making it useful to wear mask
while using public rooms particularly during the ongoing
SARS-CoV-2 pandemic.
Surface fomite contamination
Mendes and Lynch (1976) concluded that faecal bacteria
are found on bathroom surfaces in sufficient numbers to
allow the transfer of infection via the hands. Scott and
Bloomfield (1985) found opportunistic pathogens such as
P. aeruginosa and E. coli as well as other Enterobacteria
frequently on sites such as the toilet seat and handle in
addition to the toilet bowl, suggesting transfer from the
toilet. They deemed that the extent of this transfer was
limited under normal conditions and therefore the risk of
infection from such transfer was low (Bloomfield and
Scott 1997). Nevertheless, under atypical conditions, such
as when a person is experiencing bouts of acute diarrhoea
with watery stools containing a high titre of the enteric
pathogen, this risk may be greatly elevated.
Several studies have reported the contamination of
hospital patient toilets shared by patients. Amoah et al.
(2020) studying community toilets (n=8) in South
Africa found that 5363% of the restroom surfaces were
contaminated with SARS-CoV-2 by qPCR and droplet
digital PCR. The concentration of virus ranged from 259
to 13269 genome copies per cm
, the highest of that
being the toilet seat and the cistern flush handle. SARS-
CoV-2 virus has been recovered from toilet seat, bath-
room door handle, and sinks in bathrooms housing
patients with SARS-CoV-2 infections (Ding et al. 2021).
In a study of office and hospital restrooms human
adenoviruses were detected on ~70% of the surfaces, tor-
que teno virus on 9% of restrooms surfaces, 44% of hos-
pital restroom surfaces. Norovirus was only detected once
on a surface in a hospital restroom. The common occur-
rence of adenovirus probably results from prolonged
shedding from the respiratory and urinary tracts as well
as faeces. Torque teno virus infection has not been found
to be associated with any specific illness but leads to life-
long shedding of the virus without illness but is shed in
the faeces and believed to be transmitted by the faecal
oral route (Griffin et al. 2008). Noroviruses are com-
monly detected on public restroom surfaces after out-
breaks. In a study of outbreaks of norovirus outbreaks in
restrooms over 2 years in restrooms norovirus was
detected in 8% of 630 samples (86%; Kimoto et al.
2016). In a study of norovirus outbreaks on cruise ships
norovirus was detected on 563% of the toilet seats in
concentrations range from 10
to 10
genome copies
(an average of 10
). CrAssphage, which is an indicator
of human faecal contamination, was found on 685% of
the toilet seats (Park et al. 2020).
Impact of cleaning on spread of enteric
pathogens in restrooms
The spread of enteric pathogens from the toilet via aerosols
is not the only route for contamination of bathroom sur-
faces. Sponges and clothes are routinely used in US house-
holds to clean kitchen and toilet surfaces (Enriquez et al.
1997) Faecal coliforms were identified from 12 different
surfaces in 20 residential bathrooms after the homeowners’
regular cleaning regimen (Bright and Gerba, Home Survey
of Household Restrooms and Effects of Disinfectants,
University of Arizona, Tucson, Arizona, unpublished). The
cleaning tool (e.g., sponge, cloth) was also collected and
examined for contamination by coliforms and faecal col-
iforms. Coliforms were found in all 20 homes and faecal
coliforms were detected on bathroom surfaces in eight of
the 20 homes. Bacterial isolate identification was deter-
mined using API 20E strips (BioMerieux, Inc., Hazelwood,
MO) as E. coli,E. hermannii,Klebsiella pneumoniae,or
Klebsiella oxytoca. Further typing of each isolate was
accomplished via biochemical fingerprinting (K
uhn 1985),
ribotyping, and serotyping (E. coli only). In seven of the
eight homes with identified faecal coliforms, identical
strains were isolated from either the toilet itself (toilet
bowl, toilet seat bottom, flush handle) or the cleaning tool
and at least two other surfaces (up to eight surfaces) in the
bathroom (e.g., sink bowl, sink drain, sink countertop, sink
faucet handle, shower/bath drain, shower/bath surface,
floor 12 inches in front of the toilet). In the eighth home,
an identical strain was isolated from the cleaning tool and
one other surface. The results of this study are highly
Journal of Applied Microbiology ©2021 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd
on behalf of Society for Applied Microbiology.
S.E. Abney et al.Toilet hygiene
suggestive of the cleaning tool being the instrument of
transfer from the toilet to other surfaces in the bathroom.
Risk assessment of infections from restroom use
Quantitative microbial risk assessment (QMRA) is an
approach that can be used to assess the risks of infectious
disease transmission by water, food, air, and inanimate
objects (Haas et al. 2014). It has been used to develop
guidelines for setting standards for microbial risks of infec-
tion for drinking water by the United States Environmental
Protection Agency and regulatory agencies of several coun-
tries (Haas et al. 2014). Carducci et al. (2016) used it to
study the risk of infection from aerosols of adenoviruses in
different occupational settings including wastewater treat-
ment plants, solid waste landfills and toilets in healthcare
and office buildings. Virological monitoring showed the
presence of adenoviruses in the air of all these settings. The
results of QMRA showed that the risks of infection from
airborne transmission was the greatest from the aerosols
present in public restrooms. They found the number of
genome copies in office buildings averaged 10
was greater in four room hospital patient rooms (10
genome copies per m
). Amoah et al. (2020) estimated the
risk of infection from SARS-CoV-2 from touching various
surfaces in public restrooms. They used qPCR to quantify
the number of genome copies of the viruses on surfaces.
They calculated that the greatest risk of infection
to 60910
) is when a person uses the toi-
let once in a day, increasing to 10910
to 14910
if they used the toilet three times in a day. Risks of infec-
tion for a one-time exposure are considered significant if
less than 1 910
(Signor and Ashbolt 2009).
Interventions to reduce risk of transmission
In addition to improper cleaning procedures, many envi-
ronmental surfaces in the bathroom do not receive ade-
quate cleaning or, in some locations, no cleaning at all,
even in hospital environments. This includes ‘high risk’
objects such as the toilet area handholds, bathroom door-
knobs, and light switches (Carling et al. 2008).
Hypochlorite cleaners have been shown to be effective
at reducing the levels of faecal bacteria on bathroom sur-
faces (Rusin et al. 1998). Nevertheless, Barker and
Bloomfield (2000) found that Salmonella persisted in toi-
let biofilms for long periods even with disinfection. The
area under the toilet rim was particularly difficult to dis-
infect, even when using cleaners with bottles designed to
deliver product to this problematic area. Pitts et al.
(2001) found that bacteria were able to form biofilms in
toilets, even in the presence of continuous 9 mg l
rine and up to 27 mg l
free chlorine.
Scott and Bloomfield (1985) determined that continu-
ous release system disinfectants were more efficient at
reducing contamination levels of the toilet itself (e.g.,
water, toilet bowl, toilet bowl rim) than daily disinfection
or daily cleaning. In another study, automatic toilet bowl
cleaners that did not contain any disinfectant, but rather
varying levels of surfactants were found to reduce the
number of bacteria ejected from the bowl in droplets or
aerosols. The cleaner with the highest surfactant concen-
tration was the most effective at limiting aerosols (Yahya
et al. 1992).
Although enteric viruses cannot grow in biofilms, they
may persist for long periods in the toilet environment
and can be difficult to remove via normal decontamina-
tion or cleaning procedures. Noroviruses are very stable
at room temperature requiring almost 17 h at room tem-
perature for a 999% decrease in titre at room tempera-
ture (Duizer et al. 2004) and chlorine (Barker et al.
2004). Multiple outbreaks of norovirus have occurred fol-
lowing environmental contamination with the virus,
despite numerous efforts to clean the contaminated sur-
faces with detergents (Cheesbrough et al. 1997; Barker
et al. 2004; Jones et al. 2007).
It is believed that the worst indoor air quality occurs
in restrooms (Qiuchen 2018). Malodours in toilets are
believed to be associated with butyric acid, p-cresol,
and sulphur compounds mainly hydrogen sulfide,
methyl sulfide, monosulfide, disulfide and trisulfide
(Sharma et al. 2020). In urinals, ammonia and amines
are important odour producers (Perry and Schroedor
1963; Troccaz et al. 2013). The volume of flushing
water in urinals is important in the control of odours
from urine, and any residual urine leads to its degrada-
tion by bacteria and the production of ammonia
(Hashemi and Han 2017). Thus, low flush water
urinals designed to save water may result in greater
generation of odours.
Adequate ventilation of a restroom is believed the most
important factor in odour control in restrooms (Qiuchen
2018; Kimura et al. 2019). For this reason, CO
tration in restroom has been shown to be a good mea-
sure of malodours in restrooms (Qiuchen 2018).
Unfortunately, enhanced ventilation for restrooms for
odour control can put a significant demand on energy
use (Kimura et al. 2019).
Sharma et al. (2020) found that daily spray of toilets/
urinals with 10% sodium hydroxide and hydrogen per-
oxide (005%) could control the breakdown of malodor
producing bacteria and oxidizing odorous compounds at
household and public restrooms.
Journal of Applied Microbiology ©2021 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd
on behalf of Society for Applied Microbiology.
Toilet hygiene S.E. Abney et al.
Future research and directions to improve toilet
Toilet hygiene is important in the control of both enteric
and respiratory pathogens-associated illness both in pub-
lic toilets and the home. Soap and detergents alone if not
used properly cause cross contamination throughout a
restroom. Use of disinfectants is critical to preventing
movement of enteric microorganisms throughout the
restroom. Pathogen contamination of both the air and
surfaces in restrooms is well documented. Better quantifi-
cation of the risks of infection using QMRA are needed
as this well help determine what interventions will mini-
mize these risks. Colonization of biofilms and hard to
clean area (the rim under the toilet) by pathogenic
enteric bacteria such as Salmonella appear to be a prob-
lem, which has not been completely resolved. There is
also a need for improved methods for disinfecting prob-
lem areas such as the region below the toilet rim and the
area just below the water line where the formation of
biofilms has been observed. New methods such as the use
of a disinfectants that would adhere to the side of the toi-
let bowl for a longer period or ones with a longer resid-
ual effect or new methods for the physical removal of the
area by cleaning should be investigated, such as improved
scrubbing device or a chemical method (Wang et al.
2019; Krishnan 2020). These approaches would aid in the
reduction of odours and aerosols. Also, this area as a
source of odours appears not to have been studied in
detail or at least reported in the scientific literature. These
biofilms may also be areas where enteric viruses could
persist for long periods of time. Cross contamination in
homes during cleaning of the toilet and restroom also
appears to be a problem, needs investigational work to
provide mitigation guidelines for consumers.
This review was supported, in part, by a grant to the
University of Arizona from Reckitt Benckiser LLC.
Conflict of Interest
Drs Julie McKinney and M. Khalid Ijaz are engaged in
R&D at Reckitt Benckiser LLC.
Author contributions
Sarah E. Abney: Conceptualization (equal); investigation
(lead); visualization (lead); writingoriginal draft
(equal); writingreview and editing (lead). Kelly Bright:
Writingreview and editing (equal); visualization
(equal). Charles P. Gerba: Conceptualization (equal);
investigation (equal); writingoriginal draft (lead); writ-
ingreview and editing (equal); funding acquisition
(equal); supervision (equal). M. Khalid Ijaz: Conceptual-
ization (lead); writingreview and editing (equal); fund-
ing acquisition (equal); supervision (equal), validation
(lead). Julie McKinney: writingreview and editing
(equal); funding acquisition (equal); validation (equal).
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Toilet hygiene S.E. Abney et al.
... Infectious viruses such as those that cause encephalitis, smallpox, adenovirus, and SARS-CoV-2 have been detected in urine. Significant amounts of pathogens can be released into the urine, considering that people excrete 700 to 2000 mL of urine per day [33]. ...
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... Masyarakat diajak praktek bersama langkah-langkah dalam mencuci tangan yaitu: Tahap persiapan yaitu persipan bahan yang dibutuhkan air dan sabun atau handsanitizer. Sabun atau alkohol yang terkandung dalam handsanitizer berfungsi untuk membunuh mikrooganisme pada tangan, yang dapat menyebabkan penyakit (Abney et al., 2021;Booq et al., 2021;Lee et al., 2020;Saha et al., 2021). Menyingsingkan lengan baju di atas pergelangan tangan. ...
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Timbulsloko merupakan sebuah desa di wilayah pesisir Kecamatan Sayung, Demak, Jawa Tengah, Indonesia yang terdampak banjir rob sehingga seluruh desa tergenang air. Dampak kesehatan yang dialami oleh masyarakat Timbulsloko terlihat dari menurunnya status kesehatan. Genangan air yang setiap hari dilewati menyebabkan banyak masyarakat yang mengeluh penyakit kulit berupa gatal-gatal dan gangguan pencernaan, seperti diare. Kegiatan pengabdian kepada masyarakat (PkM) bertujuan untuk meningkatkan kesehatan warga masyarakat melalui penyuluhan kesehatan terkait Perilaku Hidup Bersih dan Sehat (PHBS), pemeriksaan kesehatan dan pengobatan gratis. Metode pelaksanaan PkM terdiri dari Penyuluhan kesehatan mengenai PHBS khususnya cara mencuci tangan yang baik. Sebagian besar masyarakat yang memeriksakan kesehatannya adalah perempuan 35(81,4%) dengan umur bervariasi dari balita sampai lansia. Prosentase terbesar pasien adalah umur pra lansia dan lansia 32(74,5%). Terdapat 7 (21,9 %) masyarakat yang memeriksakan diri dengan kadar gula darah sewaktu ≥ 200 mg/dl dan terdapat 18(56,3%) dengan kadar asam urat yang melebihi nilai normal. PkM di Desa Timbulsloko, Sayung, Demak bermanfaat sebagai upaya peningkatan kesehatan masyarakat yang memiliki keterbatasan akses layanan kesehatan. Penyuluhan mengenai PHBS khususnya cara mencuci tangan sesuai metode WHO bermanfaat dalam meningkatkan pengetahuan masyarakat untuk menjaga kebiasaan cuci tangan agar terhindar dari penyakit infeksi. Pemeriksaaan dan pengobatan gratis sebaiknya dilaksanakan secara berkesinambungan dalam rangka meningkatkan derajat kesehatan warga Timbulsloko yang memiliki wilayah pemukiman terendam air rob. Dukungan dari semua pihak baik akademisi, pemangku kebijakan dan politisi sangat diperlukan untuk mengangkat derajat warga Timbulsloko. Timbulsloko is a village in the coastal territory of Sayung, Demak, Central Java, Indonesia, entirely submerged by flooding. The deteriorating health status of the Timbulsloko population is evidence of the adverse health effects experienced by that culture. Many people suffer from skin diseases, such as itching, and digestive disorders, such as diarrhea, due to the daily influx of water. The activities of this community service (PkM) seek to improve the health of citizens through health coverage associated with Clean and Healthy Behavior (PHBS), medical examinations, and free medical care. The method of implementing PkM consists of health assessments regarding PHBS, specifically how to cleanse hands properly. Most of those who examined their health were women over 35 (81,4%), ranging in age from young to old. 74.5 percent of patients are younger than 32 years of age. Seven people (21.9%) self-tested for 200 mg/dl blood sugar levels, and eighteen (56.3%) had uric acid levels that exceeded normal. PkM in the villages of Timbulsloko, Sayung, and Demak contributes to improving public health in a region with limited access to health services. Knowledge of PHBS, in particular how to cleanse hands according to WHO methods, is advantageous for increasing public awareness of the importance of hand washing in preventing the spread of infectious diseases. In order to enhance the health of Timbulsloko residents residing in flooded residential areas, free inspections and treatments must be performed continuously and without cost. To raise the standards of the Timbulsloko people, support from all parties, including academics, policymakers, and legislators, is required.
... (Madarina, 2021). Research result Abney et al., (2021)added that good toilet hygiene is one that is able to minimize the potential for transmission of pathogens and the toilet in question is a flush toilet. Thus the cleanliness of the room and toilet is very important, because these hygiene conditions can reflect other hygiene conditions, so that it will have an impact on consumer satisfaction (Riell, 2021;Kim & Bachman, 2019;Tucker, 2015). ...
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Coffee shop is a rapidly growing business in the downstream agribusiness subsystem in various countries. The role of the barista and the atmosphere of the coffee shop are vital in providing consumer satisfaction to win the competition in the market. The research objective was to analyze the influence of the barista on customer satisfaction through the variable atmosphere of the coffee shop in the city of Cirebon. Cirebon City was chosen as the research location because it can represent a lowland city with many modern coffee shops around the world. The research was carried out in June-October 2022 using a survey method and a quantitative design. The research population is coffee shop consumers in Cirebon City, and the number of samples is 120 respondents. Measurement of variable indicators using a Likert Scale, data analysis using Structural Equation Modeling, and Sobel test. The study results concluded that the barista influences customer satisfaction through the coffee shop atmosphere as an intervening variable. The most dominant indicators explaining quality: barista is "hospitality," customer satisfaction is "feeling happy," and the atmosphere of the coffee shop is "coffee room/place" and "toilet." For this reason, it is recommended that coffee shop business actors improve the quality of hospitality barista, products, and room and toilet designs to help satisfy consumers and win the competition.
... Unhygienic toilet potentially increases the risk of diarrhoeal diseases and other infectious diseases (Just et al., 2018;Matini et al., 2020). Several studies emphasize the significance of adoption of hygienic toilet to minimize pathogen transmission and reduce diseases burden and suggested to focus on whole sanitation service chain including nutrient recovery and sanitation marketing (Bloomfield, 2007;Abney et al., 2021). ...
Access to water, sanitation, and hygiene (WaSH) is crucial for national development, as it improves human health and fulfills a fundamental need. This study examines the impact of a large-scale groundwater (GW) recharge scheme using secondary treated wastewater (STW) on WaSH characteristics and identifies the major determinants of improved WaSH charecteristics in drought-hit regions of Kolar district, southern India. The study quantifies improved WaSH practices by comparing WaSH characteristics between impacted areas (influenced by STW) and non-impacted areas (not influenced by STW) of Kolar, using household survey data. Pearson's chi-square and student's ttest are used to verify differences between WaSH characteristics. Furthermore, a composite WaSH score is formulated, and a hierarchical stepwise multiple linear regression model is constructed to identify major determinants of improved WaSH scores. The results show that impacted areas have better WaSH characteristics, including daily water supply by gram panchayat, enhanced toilet uses among all family. members, bathing patterns, cloth washing practices, toilet cleaning patterns, and water consumption per capita per day. The maximum and minimum WaSH scores of impacted areas were 17.50 and 6.50, respectively, while those of non-impacted areas were 14 and 4.5. This study finds that improved water availability, quality, and security due to daily water supply at the household level are the major determinants of improved WaSH practices. These results can inform policymakers in designing sanitation and hygiene improvement policies that integrate water recycling projects in drought-hit areas.
... It must be noted that the showers were already rarely used by the geriatric population. Additionally, during the first months of the pandemic (May 2020) printed stickers "Please close the toilet lid when flushing" were hung on all toilets to diminish the dispersion of secreted microorganisms to surrounding surfaces [58,59], however it is unclear how well this instruction was followed. Hospital bathrooms are often small with the sinks, toilet and shower in close proximity. ...
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Background Accumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures. Methods Environmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci. Results The CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms. Conclusions Our findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system.
Good toilet hygiene can reduce the risk of pathogenic transmission. During flushing, pathogenic bacteria can be spread by the water droplets, especially in the toilet seat. Escherichia coli (E. coli) is one of the frequently occurring Gram-negative bacterial pathogens found in the toilet seats. In this study, we investigated the potential anti-E. coli activity of some azobenzene compounds. Among them, compound 2, with the heterocyclic nitrogen in both phenyl rings, showed the strongest antibacterial effect on E. coli, with the minimum inhibitory concentration of 80 µg/mL and the minimum bactericidal concentration of 320 µg/mL Compound 2 displayed a comparative zone of clearance [(14.50±2.29) mm] to that of ampicillin [(13.17±1.76) mm]. The reactive oxygen species (ROS) assay suggested that compound 2 might induce the loss of bacteria via the oxidative stress by eliciting the generation of intracellular ROS. We further examined the potential cytotoxicity of compound 2 to the human skin HaCaT cells. Compound 2-treated skin cells showed a good maintenance of cellular morphology and a clear definition of cell nuclei, with a satisfactory cell viability (ca. 90%) at 80 µg/mL Overall, compound 2 would be a possible antibacterial coating agent for the surface sanitizer of the toilet seats to inhibit the growth of E. coli.
Flush toilets waste a significant amount of water every day due to the unavoidable adhesions between human waste and the toilet surfaces. Super‐slippery surfaces can repel complex fluids and various viscoelastic solids, however, are easily broken by the mechanical abrasions. Herein, we report the fabrication of an abrasion‐resistant super‐slippery flush toilet (ARSFT) using a selective laser sintering 3D printing technology. Unlike traditional super‐slippery surfaces with limited thicknesses which can be easily worn away, the powder sintered strategy endows the ARSFT not only with a self‐supporting 3D complex shape but also with a porous structure that can accommodate considerable lubricants for an abrasion‐resistant super‐slippery property. As a result, the as‐prepared ARSFT remains clean after contacting with various liquids such as milk, yogurt, highly sticky honey and starch gel mixed congee, demonstrating excellent repellence to complex fluids. Besides liquids, the ARSFT exhibits a high resistance to the sticky synthetic feces. Notably, even after being abraded to 1000 cycles of abrasion using sandpaper, the ARSFT maintains its record‐breaking super‐slippery capability. The concept of the 3D printed object with a superior abrasion‐resistant slippery ability will improve the development of super‐slippery materials and further save water consumption in the human society. This article is protected by copyright. All rights reserved.
Lavatories are frequently used facilities, especially on long-haul flights. Flushing a vacuum toilet in a lavatory can induce strong airflow, produce aerosols in the toilet bowl, and resuspend deposited particles from the floor. However, the exact particle transport routes and the fates of particle after toilet flushing are unclear so far. This investigation used computational fluid dynamics (CFD) to model the transient airflow and pollutant transport after a toilet flushing process in a lavatory of a commercial aircraft. The time-varying pressure profile measured in a laboratory was assigned to the drainage valve as boundary conditions. The aerosols generated inside the toilet bowl during flushing and the particles resuspended from the lavatory floor were used as particle sources. Lagrangian tracking of airborne particles in the lavatory was conducted. In addition, ammonia gas was used to examine odor perception. The multi-physics software program COMSOL 5.4 was employed for numerical solution after being validated. The results revealed that more than 70% of the generated particles in the toilet bowl are drained into sewage. A few particles may leak out of the toilet bowl and remain suspended in the air for more than five minutes when the toilet lid is open during flushing. Flushing the toilet with a closed lid can effectively reduce the particle leakage and the spread of odor gas, but it leads to greater deposition of particles on both the lid and seat. There is a slight inhalation exposure risk in the initial three minutes after flushing with a closed lid.
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Stinking urinals and toilets are universal being common in the third world countries with prevailing mismanagement and poor funding to municipalities. This problem has been addressed in a sustainable manner. Our long term studies have revealed that bi weekly night spray of sodium hydroxide (0.5% in tap water) control malodor in the household toilets. The malodor in a public urinal and toilet (5 days study) was controlled after 5 sprays of NaOH (1%) in a day (at 3h intervals). Chemical spray also reduced frequency of water flushes after use; 3-4 /day in the houses but 10 flushes/day in the public urinals (2 flushes in between sprays; first flush after 10minutes of a chemical spray and second after 2h). In addition to regular water flush after toilet use, additional flush must follow after 10 minutes of every spray. Further, weekly combined spray of sodium hydroxide (1.0%) and hydrogen peroxide (0.05%) at night is recommended in the public facilities to oxidize recalcitrant malodor compounds to non odorous biodegradable compounds. However, concentration of H 2 O 2 may be increased (maximum 0.5%) while time intervals between night sprays may be reduced considering malodor problems. These sprays may be useful in sanitizing toilets, urinals and washrooms in the hospitals during COVID pandemic. Remove under lines Public toilets and urinals are the major source of foul odor in the urban areas. Malodorous compounds in the toilets are butyric acid, p-cresol (Burton and Camb 1891, Berthelot 1918), indole, skatole (Brieger 1878) and sulfur compounds mainly hydrogen sulfide and methyl mercaptan (Moore et al. 1987, Sato et al. 2001, 2002). Dimethyl mono-, di-, and trisulfide, in some conditions, can also contribute to the toilet malodors. In addition, ammonia and amines (methyl amine, dimethylamine, ethylamines and trimethyl amine) are important in the urinals (Perry and Schroeder 1963, Troccaz et al. 2013). Genesis of Malodor The biofilms (0.10mm thick) formed on the surface of pots and pipes etc. of urinals and toilets decompose organics of urine and fecal origin releasing malodorous compounds. Although urea is a very stable compound having a half life period of about 40 years at 25 0 C (Shaw and Bordeaux 1955, Callahan et al. 2005) but urease released from microbial biofilm breaks into carbonic acid and ammonia. Growth Limiting factor of Microbes The medium pH affects microbial growth including their viability. The optimum growth of E. coli takes place between pH 5.5-8.5. Cell growth stop slowly at pH >5.5 while pH >8.5 not only stop cell growth but also kill (Source: Internet pH > 9.0 also arrests other bacteria growth such as Clostridium sporogenes, Erwinia caratovora, Psedomonas aeruginosa, Thiobacillus novellus and Streptococcus pnemoniae (Kenneth Todar "Online Textbook of Bacteriology" http://textbook The pH also affects activity of urease enzyme for urea degradation. Michaelis constant (KM) and maximum reaction rate (vmax) of urease are dependent on the pH of medium and pH effects are much smaller on Km than V max. The reaction rate (Vmax) is almost nil in the acidic medium (pH = 4) but increases with pH becoming maximum at pH = 7. Further increase in pH value decreased reaction rate of urease becoming minimum at pH= 9 (Fidaleo and Lavecchia 2003).
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Aerosolized droplets play a central role in the transmission of various infectious diseases, including Legionnaire's disease, gastroenteritis-causing norovirus, and most recently COVID-19. Respiratory droplets are known to be the most prominent source of transmission for COVID-19; however, alternative routes may exist given the discovery of small numbers of viable viruses in urine and stool samples. Flushing biomatter can lead to the aerosolization of micro-organisms; thus, there is a likelihood that bioaerosols generated in public restrooms may pose a concern for the transmission of COVID-19, especially since these areas are relatively confined, experience heavy foot traffic, and may suffer from inadequate ventilation. To quantify the extent of aerosolization, we measure the size and number of droplets generated by flushing toilets and urinals in a public restroom. The results indicate that the particular designs tested in the study generate a large number of droplets in the size range 0.3 μ m - 3 μ m , which can reach heights of at least 1.52 m. Covering the toilet reduced aerosol levels but did not eliminate them completely, suggesting that aerosolized droplets escaped through small gaps between the cover and the seat. In addition to consistent increases in aerosol levels immediately after flushing, there was a notable rise in ambient aerosol levels due to the accumulation of droplets from multiple flushes conducted during the tests. This highlights the need for incorporating adequate ventilation in the design and operation of public spaces, which can help prevent aerosol accumulation in high occupancy areas and mitigate the risk of airborne disease transmission.
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Contamination of contact surfaces with SARS-CoV-2 has been reported as a potential route for the community transmission of COVID-19. This could be a major issue in developing countries where access to basic sanitation is poor leading to the sharing of toilet facilities. In this study, we present the first report of SARS-CoV-2 contamination on key contact surfaces in shared toilets, in the city of Durban, using droplet digital PCR and assessed the probabilistic risks of COVID-19 infections. Approximately, 53-69% of the contact surfaces were contaminated, with SARS-CoV-2 viral loads per cm² ranging from 25.9 to 132.69 gc/cm². Toilet seats had the highest contamination per cm². The results suggested that the leading cause of contamination in shared toilets could be the shedding of the viral particles in feces and contaminated hands. We observed a significant reduction in viral loads on the contaminated surfaces after cleaning, showing the potential of effective cleaning on the reduction of contamination of these surfaces. The probabilistic assessment showed a high potential for COVID-19 infections. Touching the internal latch of the toilet cubicle had the highest risk of infections (4.3x10⁻²(6.0x10⁻⁴)) when a person uses the toilet once in a day, increasing to 1.0x10⁻¹(1.4x10⁻³) for three uses in a day. The risks estimated in this study were higher than any of the tolerable/acceptable risk figures proposed for COVID-19 from environmental exposure. This calls for the implementation of risk reduction measures, such as strict adherence to wearing face masks, regular washing of hands with soap, and effective and regular cleaning.
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A virus-laden particle movement from urinal flushing is simulated. Similar to the toilet-induced flushing, results indicate that the trajectory of the particles triggered by the urinal flushing manifests an external spread type. Even more alarmingly, the particle can reach 0.84 m (man’s thigh) in 5.5 s when compared with the diffusion performance of the toilet-induced one (around 0.93 m in 35 s). A more violent climbing tendency is discovered in this Letter. Wearing masks should be made mandatory in public washrooms, and anti-diffusion improvements of facilities in public washrooms are urgently needed, especially in the current “SARS-CoV-2” crisis.
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The purpose of this article is twofold, one is to provide a brief review on various lavatory cleaning devices while the other is to study the feasibility of using these devices in public toilets in developing countries. The article presents a literature review on various lavatory cleaning devices, focusing on various designs available as patent documents and commercially available toilet cleaning robots. The issues that prevent these devices from being deployed in multi-lavatory public toilet complexes in developing countries are discussed. Design considerations of a simple, cost-effective, semi-automated lavatory cleaning robot that may serve as a solution to these issues are also covered in this article.
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We describe 2 cases of healthcare-associated Legionnaires' disease in patients in France hospitalized 5 months apart in the same room. Whole-genome sequencing analyses showed that clinical isolates from the patients and isolates from the room's toilet clustered together. Toilet contamination by Legionella pneumophila could lead to a risk for exposure through flushing.
Contamination of contact surfaces with SARS-CoV-2 has been reported as a potential route for the transmission of COVID-19. This could be a major issue in developing countries where access to basic sanitation is poor, leading to the sharing of toilet facilities. In this study, we report SARS-CoV-2 contamination of key contact surfaces in shared toilets and the probabilistic risks of COVID-19 infections based on detection and quantification of the nucleic acid on the surfaces. We observed that 54–69% of the contact surfaces were contaminated, with SARS-CoV-2 loads ranging from 28.1 to 132.7 gene copies per cm². Toilet seats had the highest contamination, which could be attributed to shedding of the virus in feces and urine. We observed a significant reduction in viral loads on the contaminated surfaces after cleaning, showing the potential of effective cleaning on the reduction of contamination. The pattern of contamination indicates that the most contaminated surfaces are those that are either commonly touched by users of the shared toilets or easily contaminated with feces and urine. These surfaces were the toilet seats, cistern handles and tap handles. The likelihood (probability) of infection with COVID-19 on these surfaces was highest on the toilet seat (1.76 × 10⁻⁴(1.58 × 10⁻⁶)) for one time use of the toilet. These findings highlight the potential risks for COVID-19 infections in the event that intact infectious viral particles are deposited on these contact surfaces. Therefore, this study shows that shared toilet facilities in densely populated areas could lead to an increase in risks of COVID-19 infections. This calls for the implementation of risk reduction measures, such as regular washing of hands with soap, strict adherence to wearing face masks, and effective and regular cleaning of shared facilities.
Large numbers of bacteria and viruses when seeded into household toilets were shown to remain in the bowl after flushing, and even continual flushing could not remove a persistent fraction. This was found to be due to the adsorption of the organisms to the porcelain surfaces of the bowl, with gradual elution occurring after each flush. Droplets produced by flushing toilets were found to harbor both bacteria and viruses which had been seeded. The detection of bacteria and viruses falling out onto surfaces in bathrooms after flushing indicated that they remain airborne long enough to settle on surface throughout the bathroom. Thus, there is a possibility that a person may acquire an infection from an aerosol produced by a toilet.
Respiratory and fecal aerosols play confirmed and suspected roles, respectively, in transmitting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). An extensive environmental sampling campaign of both toilet and non-toilet environments was performed in a dedicated hospital building for patients with coronavirus disease 2019 (COVID-19), and the associated environmental factors were analyzed. In total, 107 surface samples, 46 air samples, two exhaled condensate samples, and two expired air samples were collected within and beyond four three-bed isolation rooms. The data of the COVID-19 patients were collected. The building environmental design and the cleaning routines were reviewed. Field measurements of airflow and CO2 concentrations were conducted. The 107 surface samples comprised 37 from toilets, 34 from other surfaces in isolation rooms, and 36 from other surfaces outside the isolation rooms in the hospital. Four of these samples were positive, namely two ward door handles, one bathroom toilet seat cover, and one bathroom door handle. Three were weakly positive, namely one bathroom toilet seat, one bathroom washbasin tap lever, and one bathroom ceiling exhaust louver. Of the 46 air samples, one collected from a corridor was weakly positive. The two exhaled condensate samples and the two expired air samples were negative. The fecal-derived aerosols in patients' toilets contained most of the detected SARS-CoV-2 in the hospital, highlighting the importance of surface and hand hygiene for intervention.