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).