Recurrent urinary tract infections (UTIs) are the most common bacterial infections in nursing homes, in acute care and the general practice. Increasing antibiotic resistance of enterobacteriaciae poses a challenge to the treatment of UTIs. Unlike previously thought, the bladder is colonized with bacteria, which together form the urine microbiome. Recurrent urinary tract infections are associated with a decreased urinary microbiota diversity, potentially making recolonization by bacterial interference in the bladder an alternative therapy for UTI. Pioneering studies showed that local bacterial interference in the bladder can be performed safely and has potential as prophylactic intervention.