We have already reported the effectiveness of bidets with in
vitro experiments. Namely, a model of the buttocks was smeared with
artificial diarrheal feces containing Serratia marcescens, and
wiped by the participants wearing disposable gloves with 4 sheets of
toilet paper after the use and non-use of bidets. Subsequently, the
presence of S. marcescens on the surface of the gloves was
quantified. After using the bidets, the mean count ± standard deviation
of S. marcescens was 0.067 ± 0.249 cfu/ glove, and it was 4,275 ±
6,069 cfu/ glove when bidets was not used. The results obtained were
that the cfu of S. marcescens was significantly lower when the
bidets were used (p < 0.00001) prior to wiping the
artificial diarrheal feces. Although the effect of bidets in this
fieldwork was not as significant as that of the previous in vitroexperiment, the effectiveness of bidets was confirmed as in the previousin vitro experiment.
It is estimated that microbial contamination from feces of hand after
defecation has a major impact on the spread of intestinal infections
such as norovirus gastroenteritis, Clostridioides difficilerelated infections, and enterohemorrhagic Escherichia coliinfections.5-10 For example, outbreaks resulting from
food handlers who are infected or subclinical infected with the
norovirus and does not sufficiently wash or disinfect their hands after
using the toilet, then handling food.11-14Accordingly, hand hygiene after defecation is of course
important,15 but it is also important to prevent fecal
contamination of the hand after defecation as much as possible. In this
experiment, the use of bidets was found to be effective in reducing
microbial contamination of fingers after defecation. Although bidets
were originally developed for medical use, they are presumed to be also
effective in the prevention of spreading intestinal infections.
In conclusion, the use of electric toilet seats with water spray
(bidets) was an effective method in reducing faces adhering to hands at
the time of defecation.