Bidet Toilet Use May Cause Anal Symptoms and Nosocomial Infection (2024)

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J Anus Rectum Colon. 2021; 5(4): 335–339.

Published online 2021 Oct 28. doi:10.23922/jarc.2021-027

PMCID: PMC8553346

PMID: 34746497

Akira Tsunoda¹

Author information Article notes Copyright and License information PMC Disclaimer

Abstract

Electric bidet toilets are widely used in Japan and are sanitary devices, that are integral to daily life. Approximately, half of the population washed the anus before or after defecation. Cleaning the anus after defecation using the bidets contributes to hand hygiene and local comfort, and it may be effective against constipation. However, excessive bidet use potentially causes anal pruritus and anal incontinence (AI). Physicians are advised to instruct patients with anal pruritus to avoid excessive cleaning of the anus and those with AI to discontinue bidet use. For the estimation of the inherent severity of AI, physicians should instruct a bidet user with AI to discontinue bidet use and assess the severity of AI later. Additionally, the nozzle surface and splay water of bidet toilets may be contaminated with fecal indicator bacteria, such as Escherichia coli and Pseudomonas aeruginosa, as well as antimicrobial-resistant bacteria, rendering them a potential vehicle for cross-infection. In the hospital setting, compromised patients must be cautious regarding the shared use of bidet toilets to prevent infection by antimicrobial-resistant bacteria. Specifically, they should be provided with bidet toilets exclusive for them or may need to be instructed to not use a bidet.

Keywords: bidet toilet, anal pruritus, anal incontinence, bacterial contamination

Introduction

Electric bidet toilets are automatic devices that deliver a jet of water to clean the anus after defecation. Ever since their introduction to the Japanese market in 1967, Japanese-manufactured electric bidet toilets have steadily gained popularity. According to the Cabinet Office's Consumer Trend Survey[1], the diffusion rate of bidet toilets in households was 80.2% in March 2020, and the number of these units owned per 100 households was 114.5, which is more than one per household (Figure 1)[2]. Bidets have been developed to incorporate different functions to improve user comfort. Presently, users can select their preferred force, thickness (narrow or wide), and temperature of the water jet. Bidet toilets are installed not only in general households but also in public facilities such as commercial buildings, hotels, airports, and hospitals, and have emerged as a sanitary device that is integral to daily life in Japan.

Bidet Toilet Use May Cause Anal Symptoms and Nosocomial Infection (2)

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Advantages of Using Bidet Toilets

One advantage of bidet use is that it contributes to hand hygiene. Oie et al.[3] conducted a simulation experiment to examine hand contamination from wiping the buttocks after the use and non-use of an electric bidet toilet with splay water. A model of the buttocks was smeared with an artificial liquid stool containing Serratia marcescens and wiped by the participants with toilet paper after the use or non-use of the splay water. The number of bacteria adhering to the hand was significantly lower when the splay water was used before wiping the artificial liquid stool. This finding corroborates the effectiveness of splay water in preventing defecation-related hand contamination.

A positive effect on toileting has also been highlighted. When women aged 75 years or older were asked to use bidet toilets in a nursing home, approximately 50% of them reported a sense of comfort and cleanliness after defecation[4]. The usefulness of bidet use against constipation or defecation difficulties has also been reported. -Uchikawa et al.[5] discovered that the use of bidets induced defecation in 15/20 (75%) patients with spinal cord injury. In a study by Shigematsu et al.[6] of 18 patients who had undergone hysterectomy, 15 (83%) of the patients reported smooth bowel movement during the postoperative period when using the bidet toilets. In a study of pregnant women in Turkey, the group that washed their anus before defecation reported a significant improvement in constipation scores compared with the control group, despite not using electric bidet toilets[7].

Regarding the anorectal physiological benefits, Ryoo et al.[8] found that bidet use at low or medium water jet pressure, at a warm temperature, and with a wide-type water jet potentially reduce anal pressure with an effect resembling that of a warm sitz bath. The authors suggested that the effect of relaxing anal sphincter pressure may be beneficial to patients with elevated anal pressures due to anorectal diseases, such as an anal fissure or hemorrhoids, and during postoperative periods after surgery for anal diseases. Watanabe et al.[9] reported that bidet use at a warm temperature for 10 min increased blood flow in the submucosa of the anus, which potentially contributes to postoperative wound healing.

Current Use of Bidet Toilets

Previously, we conducted a survey of electric bidet use among Japanese community-dwelling residents and found that 55% (2,724/4,952) of the respondents washed the anus either before or after defecation[10]. Additionally, at least 30% (828/2,724) of bidet users washed before defecation, and 70% of the respondents reported “Because it aids defecation by stimulating the anus with a jet of water,” and 20% reported “Because it aids defecation like an enema when water penetrates the rectum.” In a survey of bidet use in 575 outpatients conducted by Yano et al.[11], 349 (61%) washed the anus at every defecation and 75 (13%) did so occasionally. Among the 424 bidet users, 392 (93%) reported that this was for anal cleanliness and 111 (26%) reported that this eased defecation. In a survey of college students, 34% (47/139) of the female students and 44% (43/98) of their male counterparts reported using the washing function of bidet toilets[12]. Overall, approximately half of the population washed the anus before or after defecation.

Bidet Toilet Use and Anal Symptoms

1) Anal pruritus

Excessive bidet use may cause itching of the anus[13]. Kurokawa et al.[14] reported that perianal dermatitis found in 932/3,541 (26%) patients was due to excessive bidet use. In our surveillance, the incidence of respondents who complained of anal pruritus was 14% (345/2,449), and multivariate analysis of the risk factors showed that the correlates for anal itching included the active use of bidet toilets, such as washing before defecation, and using relatively warm water for washing the anus[10]. The pathophysiology underlying anal pruritus is the shedding of sebum around the anus due to excessive bidet toilet use, leading to skin dryness[13].

2) Anal incontinence

In our surveillance, 6% (156/2,534) of the respondents experienced fecal incontinence at least once a month after using bidets[10]. In another study that investigated the relationship between AI (defined as incontinence to gas, mucus, or feces) and bidet use, 49 patients with AI who had habitually used bidets were asked to discontinue bidet use for a median of 4 weeks. Consequently, both the AI score (Figure 2) and the frequency of fecal incontinence were significantly lower at follow-up than at baseline[15]. Although the causes of AI are multifactorial, it is possible that when patients wash the anus using a bidet, water may penetrate the rectum, especially in those with a lax anal sphincter. Enemas induce the defecation reflex and increase bowel peristalsis with water streaming into the rectum, thereby resulting in post-defecation AI symptoms.

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Figure 2.

Fecal incontinence severity index scores at the baseline and follow-up. Boxes show median values with upper and lower quartiles. The verticalline extends from the minimum to the maximum values. *P<0.0001 versus the baseline (the Mann-Whitney U-test).

3) Anal fissure

A previous study reported 10 cases of anterior fissures due to bidet toilet use for 1-5 min[16]. The author speculated that the stronger water pressure of the bidet use with a longer duration may be the causative factor of the anterior fissure.

Bidet Toilet Use and Bacterial Contamination

Outbreaks of resistant bacteria have been reported to be due to the contamination of the cleaning nozzles of bidet toilets in hospitals[17-19]. In each case, the outbreaks were reportedly due to bidet use by patients in the hematology department, and it is speculated that antimicrobial-resistant bacteria attached to the nozzles spread to other patients through the splay water. According to the outbreak of drug-resistant bacteria in the hematology unit, Enterobacter cloacae producing metallo-β-lactamase (MBL) infection was found in16 (5 males and 11 females) patients[17] and Pseudomonas aeruginosa producing MBL infection was found in 24 (18 males and 6 females) patients[18].

Iyo et al.[20] investigated the actual status of bacterial contamination of water storage-type bidet toilets installed on university campuses and found that Escherichia coli and Pseudomonas aeruginosa were detected at frequencies of 2.4% (3/127) and 1.6% (2/127), respectively, in the splay water. It is inferred that fecal indicator bacteria attached to the nozzle surface and around the water discharge hole were mixed with the splay water and detected. The heterotrophic bacteria in the splay water proliferated significantly more than those in the tap water. This might have been because the heterotrophic bacteria in the tap water proliferated in the water storage tank and nozzle piping as the residual chlorine concentration decreased because of heating of the water storage tank[20,21]. We have also reported similar findings regarding the remarkable growth of heterotrophic bacteria in the splay water of bidet toilets[22].

Table 1

Number of Toilets Sampled That Were Positive for Enterobacteriaceae and Pseudomonas Spp.

Authors	No. of toilets sampled	Isolates	Isolated from
Authors	No. of toilets sampled	Isolates	Nozzle surface	Splay water
Iyo et al. [20]	127	E. coli	-	3 (2.4%)
		Enterococcus spp.	-	4 (3.1%)
		Pseudomonas spp.	-	2 (1.6%)
Kanayama Katsuse et al. [23]	292	E. coli	34 (11.6%) (1: ESBL producer)	-
		Enterococcus spp.	58 (19.9%)	-
		Klebsiella spp.	12 (4.1%)	-
		Citrobacter spp.	3 (1.0%) (1: ESBL-producing C. koseri)	-
		Pseudomonas aeruginosa	6 (2.1%)
Tsunoda et al. [22]	192	E. coli	5 (2.6%) (1: ESBL producer)	4 (2.1%) (1: ESBL producer)
		Enterococcus spp.	7 (3.6%) (1: E. faecalis)	0 (0%)
		Klebsiella spp.	1 (0.5%) (1: K. pneumoniae)	2 (1.0%) (2: K. oxytoca)
		Pseudomonas spp.	0 (0%)	0 (0%)

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Guidance

Excessive anal washing with bidets is considered the primary cause of anal symptoms. Sasaki et al.[13] discouraged excessive anal washing and the use of topical steroids for anal pruritus and reported that 94 patients with the disease were treated according to the treatment plan, and all (100%) recovered successfully. This treatment plan is quite reasonable. In the present writer's clinic, anal cleaning is specifically restricted to less than 5 s with weak water pressure and a wide water jet, because a strong water pressure or a thin water jet may feel harder and more stimulating at the anus. Patients with AI are instructed to discontinue washing to prevent the splay water from penetrating the rectum. Conversely, when researchers estimate the severity of AI using the AI score, they should check whether a patient with AI is a bidet user or not. If the patient uses a bidet, instead of treating AI immediately, the patient should be instructed to discontinue bidet use for a certain period of time and the severity of AI should be assessed again later.

To prevent infection by antimicrobial-resistant bacteria, not only patients with hematological malignancies but also compromised hosts, such as patients with severe inflammatory bowel disease, terminal cancer, and those receiving hemodialysis, must be cautious in the shared use of bidet toilets. Specifically, they should be provided with bidet toilets exclusive for them or may need to be instructed to not to use a bidet. Additionally, the appropriate cleaning method for bidet toilets, including the nozzle or the service life of these units, must be considered. Recently, an on-demand type of bidet toilet with a nozzle cleaning mechanism that uses electrolyzed hypochlorite water, has been devised to replace the water storage-type bidet toilets; however, in the nozzle-contamination test, E. coli in the splay water was sterilized, whereas P. aeruginosa was not completely sterilized[24].

Conclusion

The current status and issues regarding the use of bidet toilets were reviewed. The bidet toilet is the most widely used toilet in Japan, and approximately half the population washes the anus before or after defecation. Excessive bidet use should be considered an etiologic factor in patients undergoing a medical examination for anal pruritus or AI. In the hospital setting, compromised patients should be cautious regarding the shared use of bidet toilets to prevent infection by antimicrobial-resistant bacteria. Further studies are required to confirm the issues surrounding bidet toilet use.

Coronavirus disease 2019 has been prevalent since 2020, and the novel severe acute respiratory syndrome coronavirus 2 has reportedly been detected in the stool or urine of patients affected by this disease[25]. Consequently, the cleaning of bidet toilets (including the nozzles) that are installed in hospital rooms dedicated to this disease must be prioritized.

Conflicts of Interest

There are no conflicts of interest.

Author Contributions

Akira Tsunoda: the design of the research, acquisition of data, analysis and interpretation of data, drafting of the article, and final approval of the version to be published.

Approval by Institutional Review Board (IRB)

No approval from any IRB was required because this review article was based on previously published papers.

References

1. Cabinet Office, Government of Japan. Diffusion and home ownership of consumer durable goods. [Internet]. 2021 [cited 2021 Jan 30]. Available from: https://www.escri.cao.go.jp/jp/stat/shouhi/shouhi.html Japanese.

2. Japanese Sanitary Equipment Industry Association. Statistics, data -various statistics. [Internet]. 2021 [cited 2021 Jan 30]. Available from: https://www.sanitary-net.com/trend/spread.html Japanese.

3. Oie S, Aoshika H, Arita E, et al. The use of electric toilet seats with water spray is efficacious in maintaining hand hygiene in experimental model. Jpn J Infect Dis. 2018 Jul; 71(4): 306-8. [PubMed] [Google Scholar]

4. Cohen-Mansfield J, Biddison JR. The potential of wash-and-dry toilets to improve the toileting experience for nursing home residents. Gerontologist. 2005 Oct; 45(5): 694-9. [PubMed] [Google Scholar]

5. Uchikawa K, Takahashi H, Deguchi G, et al. A washing toilet seat with a CCD camera monitor to stimulate bowel movement in patients with spinal cord injury. Am J Phys Med Rehabil. 2007 Mar; 86(3): 200-4. [PubMed] [Google Scholar]

6. Shigematsu T, Kawanishi C, Minota S. [Intervention in natural bowel movement in after hysterectomy or myomectomy -Evaluation of intervention stimulated anus and anal canal with electric bidet]-. Proceeding of Research in Konan Women's College. 2010 Mar; 4: 39-49 Japanese. [Google Scholar]

7. Alan S, Gozuyesil E, Surucu SG. The effect of bidet use on severity of constipation and quality of life among pregnant women. Yonago Acta Med. 2020 Aug; 63(3): 205-13. [PMC free article] [PubMed] [Google Scholar]

8. Ryoo S, Song YS, Seo MS, et al. Effect of electronic toilet system (bidet) on anorectal pressure in normal healthy volunteers: influence of different types of water stream and temperature. J Korean Med Sci. 2011 Jan; 26(1): 71-7. [PMC free article] [PubMed] [Google Scholar]

9. Watanabe K, Watanabe M, Masuda H, et al. Change of anodermal blood flow using warm water irrigation toilet seat device. J Jpn Soc of Coloproctol. 1999 May; 52(5): 431-9. Japanese. [Google Scholar]

10. Tsunoda A, Takahashi T, Arika K, et al. Survey of electric bidet toilet use among community dwelling Japanese people and correlates for an itch on the anus. Environ Health Prev Med. 2016 Nov; 21(6): 547-53. [PMC free article] [PubMed] [Google Scholar]

11. Yano T, Asano M, Matsuda Y. Is there “warm-water toilet seat syndrome”? Jap Med J. 2013 Aug; 4658: 53-6. Japanese. [Google Scholar]

12. Sato C, Iseki A, Miki N, et al. Use of the warm-water lavage toilet seats by male and female university students. J Phys Fitness Nutr Immunol. 2016 Oct; 26(3): 169-72. [Google Scholar]

13. Sasaki M, Sasaki I, Matsuda Y. Steroid ointment tapering treatment for pruritus ani. J Jpn Soc Coloproctol. 2005 Jun; 58(6): 303-11. Japanese. [Google Scholar]

14. Kurokawa A, Kitsuki K. Problems with habitual use of warm-water toilet seats: “warm-water toilet seat syndrome” from the perspective of a proctologist. Clin Proctol. 2017 Nov; 9(1): 1-8. Japanese. [Google Scholar]

15. Tsunoda A, Kusanagi H. A retrospective investigation on electric bidet use as a possible cause of anal incontinence. J Anus Rectum Colon. Forthcoming 2021. [PMC free article] [PubMed] [Google Scholar]

16. Garg P. Water stream in a bidet-toilet as a cause of anterior fissure-in-ano: a preliminary report. Colorectal Dis. 2010 Jun; 12(6): 601-2. [PubMed] [Google Scholar]

17. Sato H, Okamoto M, Hagiwara M. A study on daily cleaning of bidet toilets in consideration of countermeasures against resistant bacteria- Experience of an outbreak of MβL-producing E. cloacae in a hematology ward. Proceeding of Life Extension Institute. 2015 Dec; 27: 45-50. Japanese. [Google Scholar]

18. Hayashi M, Nakai I, Fujiwara H, et al. Transmission of drug resistant Pseudomonas aeruginosa in the hematology unit associated with toilet seats with bidet function. J Jap Soc Infect Prev Contr. 2015 Jun; 30(5): 317-24. Japanese. [Google Scholar]

19. Ozaki M, Mori H, Furukawa K, et al. Pollution from nozzles of warm-water toilet seats contributes to multi-drug resistant Pseudomonas aeruginosa. J Jap Soc Infec Prev Contr. 2018 Jul; 33(6): 285-9. Japanese. [Google Scholar]

20. Iyo T, Asakura K, Nakano M, et al. Bidet toilet seats with warm-water tanks: residual chlorine, microbial community, and structural analyses. J Water Health. 2016 Feb; 14(1): 68-80. [PubMed] [Google Scholar]

21. Sato C, Iseki A, Miki N, et al. Standard plate count bacteria in the bidet lavage water of warm-water lavage toilet seats in women's public restrooms. J Phys Fitness Nutr Immunol. 2017 Nov; 27(3): 152-5. [Google Scholar]

22. Tsunoda A, Otsuka Y, Toguchi A, et al. Survey on bacterial contamination of bidet toilets and relation to the interval of scrubbing these units. J Water Health. 2019 Dec; 17(6): 863-9. [PubMed] [Google Scholar]

23. Kanayama Katsuse A, Takahashi H, Yoshizawa S, et al. Public health and healthcare-associated risk of electric, warm-water bidet toilets. J Hosp Infect. 2017 Nov; 97(3): 296-300. [PubMed] [Google Scholar]

24. Kuwahara-Arai K, Hui Z Hori S. Examination of the sanitization condition of the nozzle of warm-water toilet seats. J Jap Soc Infec Prev Contr. 2017 Feb; 32(3): 127-30. Japanese. [Google Scholar]

25. Jones DL, Baluja MQ, Graham DW, et al. Shedding of SARS-CoV-2 in feces and urine and its potential role in person-to-person transmission and the environment-based spread of COVID-19. Sci Total Environ. 2020 Dec; 749: 141364. [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of the Anus, Rectum and Colon are provided here courtesy of The Japan Society of Coloproctology

Given the detailed information provided about the article from the "Journal of Anus Rectum Colon," it's evident that the article delves deep into the topic of electric bidet toilets, specifically focusing on their use in Japan.

Electric Bidet Toilets in Japan: An Overview

Introduction and Popularity:
- Electric bidet toilets, devices that deliver a jet of water to clean the anus post-defecation, have become an essential part of Japanese households since their introduction in 1967.
- As of March 2020, the penetration rate of bidet toilets in Japanese households was 80.2%, with more than one unit per household.
- These toilets are not only found in homes but are also prevalent in public facilities like hotels, airports, and hospitals.
Advantages of Bidet Use:
- Hand Hygiene: Research indicates that bidet use reduces the risk of hand contamination after defecation.
- Toileting Comfort: Bidet use has shown to provide comfort and cleanliness post-defecation, especially for specific demographics like the elderly and patients with specific medical conditions.
- Anorectal Physiological Benefits: Bidet use at specific pressures and temperatures can reduce anal pressure, potentially benefiting patients with anorectal diseases.
Current Usage Patterns:
- Surveys indicate that about half of the Japanese population uses bidet toilets either before or after defecation. Reasons cited include enhanced cleanliness and facilitation of the defecation process.
Potential Issues and Risks:
- Anal Pruritus: Excessive use of bidets, especially with warm water, can lead to itching around the anus due to sebum shedding and skin dryness.
- Anal Incontinence: Some users reported experiencing fecal incontinence after habitual bidet use, especially in those with a lax anal sphincter.
- Bacterial Contamination: Bidet nozzles can be contaminated with fecal indicator bacteria like Escherichia coli and Pseudomonas aeruginosa. Hospitals have reported outbreaks of antimicrobial-resistant bacteria due to bidet use, emphasizing the need for caution, especially among vulnerable patient populations.
Guidance and Recommendations:
- Physicians advise patients with anal pruritus to avoid excessive bidet use and those with anal incontinence to discontinue its use temporarily for assessment.
- To prevent bacterial contamination and infections, especially in healthcare settings, compromised patients should either have exclusive access to bidet toilets or be advised against their use.

In summary, while electric bidet toilets have become an integral part of daily life in Japan, their excessive or inappropriate use can lead to specific health issues. Proper guidance, awareness, and precautions, especially in vulnerable populations and healthcare settings, are essential to maximize their benefits while minimizing risks.