Prevention of recurrent urinary tract infections.

Urinary tract infections (UTI) are among the most frequent bacterial infections in the community and health care setting. Mostly young and, to some extent, postmenopausal women are affected by recurrent UTI (rUTI) defined as ≥3 UTI/year or ≥2 UTI/half year. In contrast, rUTI is rare in healthy men. On the other hand, rUTI are frequently found in female and male patients with complicating urological factors, e.g. urinary catheters, infection stones. Remediable predisposing factors in uncomplicated rUTI in women are rare. In complicated rUTI the success depends mainly on the possibility to eliminate or at leastimprove the complicating risk factors. Continuous antibiotic prophylaxis or postcoital prophylaxis, if there is close correlation with sexual intercourse, are most effective to prevent rUTI. Nitrofurantoin, trimethoprim (or cotrimoxazole), and fosfomycin trometamol are available as first-line drugs. Oral cephalosporins and quinolones should be restricted to specific indications. Antibiotic prophylaxis reduces the number of uropathogens in the gut and/or vaginal flora and reduces bacterial "fitness". Given the correct indication, the recurrence rate of rUTI can be reduced by about 90%. Due to possible adverse events and the concern of selecting resistant pathogens, according to the guidelines of the European Association of Urology antimicrobial prophylaxis should be considered only after counselling, behavioural modification and non-antimicrobial measures have been attempted. In postmenopausal patients vaginal substitution of oestriol should be started first. Oral or parenteral immunoprophylaxis is another option in patients with rUTI. Other possibilities with varying scientific evidence are prophylaxis with cranberry products, specific plant combinations or probiotics. The prophylaxis of catheter-associated UTI should employ strategies which result in a reduction of frequency and duration of catheter drainage of the urinary tract. The currently available catheter materials have only little influence on reducing catheter-associated rUTI.