More than an infection: the ecological puzzle of recurrent urinary tract infections.

Recurrent urinary tract infections (rUTIs) represent one of the most common infectious conditions worldwide, yet their pathophysiology extends far beyond repeated episodes of acute bacterial cystitis. Increasing evidence indicates that recurrence may arise through overlapping mechanisms including reinfection from intestinal or periurethral reservoirs, intracellular bacterial persistence, microbial dysbiosis, impaired mucosal immunity and chronic inflammatory remodelling of the bladder microenvironment. Current diagnostic frameworks remain largely based on symptom-based definitions and standard urine culture, approaches that incompletely capture the biological complexity of recurrent disease. This limitation is evident even at the definitional level, where clinically pragmatic categories often fail to reflect the heterogeneous mechanisms underlying recurrence. Advances in expanded urine culture techniques, metagenomics and metabolomics have reshaped the understanding of the urinary tract as a dynamic ecological system interconnected with vaginal, intestinal and prostatic microbial compartments. These approaches have identified diverse microbial communities, virulence-associated functional profiles and host-microbe interactions linked to recurrence-prone phenotypes. Significant challenges continue to persist in elucidating the biological mechanisms driving recurrence. Addressing these gaps is essential to improve disease characterization and support the development of more effective diagnostic and therapeutic approaches.