Intravesical therapies for catheter-associated urinary tract infections: current approaches and future directions

SUMMARYUrinary tract infections (UTIs) are among the most common bacterial infections worldwide, with catheter-associated UTIs (CAUTIs) representing a major subset in healthcare settings. CAUTIs significantly increase patient morbidity, mortality, hospital stays, and healthcare costs, while driving antibiotic overuse and antimicrobial resistance (AMR). Systemic antibiotics often fail due to poor biofilm penetration, localized infection sites, and rising multidrug resistance, highlighting the urgent need for alternative, targeted therapies. This review discusses the role of intravesical therapies in both the treatment and prevention of CAUTIs, with a primary emphasis on therapeutic applications. The bladder is an accessible target for local treatment, as catheters can be repurposed for drug delivery. These devices are frequently colonized by biofilm-forming bacteria that contribute to persistent infection and treatment failure. This review explores intravesical therapy, the direct instillation of antimicrobial agents into the bladder, as a promising strategy to improve CAUTI management and mitigate AMR. We examine CAUTI pathogenesis, biofilm development, and current clinical approaches, including antimicrobial stewardship, catheter management, and coating technologies. Evidence for intravesical antibiotics such as gentamicin, amikacin, colistin, fosfomycin, and trimethoprim is reviewed alongside limited data from clinical trials, and applications in other urological disorders. Non-antibiotic alternatives, including sterile saline, antiseptic solutions, bacteriophages, antimicrobial peptides, natural bioactives, probiotics, and silver nanoparticles, are also discussed, particularly for their potential synergistic use with antibiotics to reduce resistance emergence. Despite encouraging results, intravesical therapy faces challenges such as limited clinical data, lack of standardized protocols, and delivery barriers. This review summarizes current evidence, identifies research gaps, and proposes directions to advance this underused strategy against CAUTIs amid escalating antibiotic resistance.