Catheter-Associated Urinary Tract Infections: Understanding the Interplay Between Bacterial Biofilm and Antimicrobial Resistance.

The increasing use of urinary catheters in healthcare, driven by an aging population and escalating antimicrobial resistance, presents both benefits and challenges. While they are essential to managing urinary retention and enabling precise urine output monitoring, their use significantly increases the risk of catheter-associated urinary tract infections (CAUTIs), the most common type of healthcare-associated infection. CAUTI risk is closely linked to the duration of catheterization and the formation of bacterial biofilms on catheter surfaces. These biofilms, often composed of polymicrobial communities encased in an extracellular matrix, promote persistent infections that are highly resistant to conventional antimicrobial therapies. Common CAUTI uropathogens include E. coli, E. faecalis, P. aeruginosa, P. mirabilis, K. pneumoniae, S. aureus, and Candida spp. The complexity and resilience of these biofilm-associated infections underscore the urgent need for innovative treatment strategies. Therefore, dynamic in vitro bladder infection models, which replicate physiological conditions such as urine flow and bladder voiding, have become valuable tools for studying microbial behavior, biofilm development, and therapeutic interventions under real clinical conditions. This review provides an overview of CAUTIs, explores the role of biofilms in sub-optimal responses to antimicrobial treatment and advances in model systems, and presents promising new approaches to combating these infections.