Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 18 4 2026 08 04 482 489 Wani Gunardi Department of Microbiology, Faculty of Medicine and Health Sciences, Krida Wacana Christian University, Jakarta, Indonesia Ade Dharmawan Department of Microbiology, Faculty of Medicine and Health Sciences, Krida Wacana Christian University, Jakarta, Indonesia Kris Herawan Timotius Department of Biochemistry, Faculty of Medicine and Health Sciences, Krida Wacana Christian University, Jakarta, Indonesia 2026 02 18 2026 05 31 Background and Objectives: Catheter-associated urinary tract infections (CAUTIs) are common healthcare-associated infections mainly caused by biofilm formation on urinary catheters. This study aimed to provide evidence-based catheter management strategies to reduce CAUTI risk through biofilm prevention. Materials and Methods: This prospective observational study included 109 adult patients undergoing urinary catheterization between September 2017 and January 2018. Urine samples were collected after catheter insertion and before catheter removal. Bacteriuria was screened using flow cytometry and confirmed by urine culture. Removed catheters were cultured to assess biofilm formation, while isolates were tested for biofilm-forming ability using Congo Red Agar (CRA). Results: The mean catheterization duration was 5.6 ± 2.1 days, and most patients were catheterized for ≥5 days. Bacteriuria was significantly associated with catheterization (p = 0.029). Antibiotic use reduced bacteriuria incidence (p < 0.001) but did not significantly reduce biofilm formation (73.4%, p > 0.05). CRA-positive isolates showed 1.5-fold greater biofilm-forming potential. Female sex, early bacteriuria, and catheterization >5 days were associated with biofilm formation. Conclusion: Urinary catheterization promotes biofilm and increases CAUTI risk. Although antibiotics reduced bacteriuria, they showed limited efficacy against biofilms. Early bacteriuria screening, routine monitoring, biofilm prevention, and limiting catheter duration may help reduce CAUTI incidence. https://ijm.tums.ac.ir/index.php/ijm/article/view/6070 https://ijm.tums.ac.ir/index.php/ijm/article/download/6070/1908