There are several limitations in the study. The first is a lack of generalizability because the study was done in three ICUs in one hospital. But, perineal care practice is one of the routine and universal care offered in ICUs, so this result can likely be confidently applied to the other hospitals. The second limitation is a methodological flaw by using asymptomatic bac- teriuria as the endpoint. CDC’s definition of UTI comprises symptomatic UTI and asymptomatic bac- teriuria. Asymptomatic bacteriuria may not progress to UTI, so clinical trials that used bacteriuria as an endpoint are methodologically incorrect (Trautner, Hull, & Darouiche, 2005). But, this study was done in ICUs and it was almost impossible to collect UTI symptom data from the patients who were in artifi- cial ventilation or who were unconscious. The third limitation is the small sample size. We could collect urine samples from all patients at baseline and during 1 week after beginning the catheter. But, only 53 and 25 samples were collected during the 1–2 and 2–4 weeks after beginning the perineal care, respectively. Although we excluded the cases that developed CAUTI, the sample size was still smaller than ex- pected. Also, urine samples could not be collected from patients who died or who were transferred to other places, because nurses in charge were not able to find a time to collect the urine samples before removing the catheters in that situation.