METHODS
The number of microbe adhering to gloves after defecation of 32 nursing
students (17 males and 15 females) with and without the use of bidets
was examined. Double gloves (Plastic Glove No. 2500 Kyowa Ltd., Osaka,
Japan) were worn and the number of microbe adhering to the gloves after
wiping with four layers of toilet paper was examined. Four sheets of
toilet paper were used because a survey conducted by the Japan Sanitary
Equipment Industry Association with 1,748 subjects on the number of
sheets and the length of toilet paper for wiping revealed that 4 sheets
of toilet paper was the most frequently used amount.2The outer gloves of the double gloved hands that held the toilet paper
were peeled and placed into bottles containing 200 mL of normal saline
and were subjected to sonication at 36 kHz (Since Sonic 100, Ikemoto
Scientific Technology Co., Ltd., Japan) for 5 min. 3,4Each sample was diluted 10-fold, 100-fold and 1000-fold in sterile
saline; four aliquots (0.25 mL each) of each dilution and of an
undiluted sample were plated on four trypticase soy agar (TSA) . In
addition, the remaining saline sample (ca. 200 mL) in the bottle
was filtered through a 0.22㎛ membrane filter (diameter, 5 cm; Nippon
Thermo Scientific, Wilmington, NC, USA), which was placed on TSA
plates.4 These TSA were cultured aerobically at 35℃
for 48 hr. In the case where the undiluted inocula on TSA became less
than 5 colony forming units (cfu), the cfu with the membrane filtration
technique on TSA were counted. This experiment was conducted with the
participation of volunteer nursing students from the Ube Frontier
University (Ube City, Yamaguchi Prefecture). Therefore, permission was
obtained from the Ube Frontier University Ethics Review Committee
(Title: Hands and finger contamination after defecation - comparison of
use with and without warm water washing toilet seats (bidets) -,
Approval date; November 8, 2017, Examination certificate management
number; 17007).