The study is to investigate whether chlorhexidine (CHG)-based antiseptics is more effective to prevent catheter-related urinary tract infection (CAUTI) among inhospital patients who required Foley catheter insertion. This is a cluster-randomised, step-wedged clinical trial, in which every participated unit will used three different Foley catheter insertion protocols during the study period:

1. Iodine protocol: using 10% povidone-iodine as the primary antiseptic during Foley insertion. This is the routine practice before this study in the participated hospital, as well as many Taiwanese hospitals.
2. CHG protocol: instead of povidone-iodine solution, use 2% aqueous CHG solution as the primary disinfectant during Foley solution.
3. CHG plus protocol: additional to 2% CHG solution, added 0.5% CHG impregnated gel as the lubrication during Foley insertion.

This is a open-labelled, cluster-randomized, step-wedged clinical trial aimed to observe the incidence if CAUTI during the designated study period (12 months for all participated units). All included units will start with the iodine protocol, which is the standard practice in the hospital, and then switched to CHG protocol than CHG plus protocol according to the results of randomization. Each unit will be randomized in to three different groups (A, B, and C):

Group A) 2 months of iodine protocol, followed by 4 months of CHG protocol, followed by 6 months of CHG plus protocol.

Group B) 4 months of iodine protocol, followed by 4 months of CHG protocol, followed by 4 months of CHG plus protocol.

Group C) 6 months of iodine protocol, followed by 4 months of CHG protocol, followed by 2 months of CHG plus protocol.

All unit will be monitored and compared for the occurrence of CAUTI, which is defined in accordance to the definition from the National Healthcare Safety Network (USCDC).

This is a cluster-randomized clinical trial. The enrollment is for healthcare units (wards, ICUs) in the participated hospitals rather than individuals. Patients who were admitted in the included unit with be enrolled in our study automatically.

Inclusion Criteria (for units):

• Adult acute care wards or intensive care units, which primarily care for adult patients aged above 18 years.
• Currently not using chlorhexidine as disinfectants for Foley catheter insertion or routine care.
• Had patients who required Foley catheter insertion during the last 12 months prior to inclusion.
• Willing to implant measures to improve the rate of CAUTI, and to participate and follow the study protocol in our study.

Exclusion Criteria (for units):

• Units currently using chlorhexidine as disinfectants for Foley catheter insertion or routine care.
• Wards or intensive care units with patients aged below 18 years of age in their routine practice.

Owing to the study design, informed consent is waived by the Research Ethic Committee of National Taiwan University Hospital. Therefore, individual data could not be shared as there is no consent.