Understanding individual and population-specific risk factors associated with recurrent urinary tract infections (UTIs) can help physicians tailor prophylactic strategies. Frequent intercourse, vulvovaginal atrophy, change of the local bacterial flora, history of UTIs during premenopause or in childhood, family history, and a nonsecretor blood type are substantiated risk factors for recurrent uncomplicated UTIs. This is a narrative review based on relevant literature according to the experience and expertise of the authors. Asymptomatic bacteriuria is generally benign; however, during pregnancy it is more common and is associated with an increased likelihood of symptomatic infection, which may harm the mother or fetus. Screening of pregnant women and appropriate treatment with antimicrobials must be balanced with the potential for adverse treatment-related outcomes; appropriate prophylaxis should be considered where possible. High-quality data are currently lacking on risks related to asymptomatic bacteriuria in pregnancy and further data in this hard-to-study population should be a primary concern for researchers. Incomplete voiding represents the primary risk factor for UTIs associated with conditions such as urinary incontinence and prolapse. Correcting the presence of residual urine remains the most effective prophylaxis in these populations. Bladder function alters throughout life; however, changes in function may be particularly profound in clinical populations at high risk of UTIs. Patients with neurogenic bladder will also likely have other evolving medical issues which increase the risk of UTIs, such as repeated catheterization and increasing residual urine volume. More aggressive antimicrobial prophylactic strategies may be appropriate in these patients. Again, the paucity of data on prophylaxis in these high-risk patients requires the attention of the research community.

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The branches of the immune system work in concert to defend against pathogens and prevent tissue damage due to excessive inflammation. Uropathogens in general, and uropathogenic Escherichia coli (UPEC) in particular, have evolved a diverse range of virulence mechanisms to avoid detection and destruction by the mucosal immune system of the urinary tract. Research towards a vaccine active against UPEC continues but has yet to be successful. Orally administered immunomodulatory bacterial lysates both stimulate and modulate the immune response in the urinary tract via the integrated mucosal immune system. The 2018 European Association of Urology (EAU) guidelines on treating acute uncomplicated cystitis recommend aiming for rapid resolution of symptoms, reduction of morbidity, and prophylaxis against reinfection. Recommended short-term antibiotic therapy has the advantage of good compliance, low cost, few adverse events, and low impact on bacterial flora. Antibiotic treatment of asymptomatic bacteriuria is only indicated during pregnancy and before invasive interventions. For recurrent infection, prophylaxis using behavioral modification and counseling should be employed first, then nonantibiotic prophylaxis, and, finally, low-dose continuous or postcoital antibiotic prophylaxis. The 2018 EAU guidelines give a strong recommendation for the oral bacterial lysate immunomodulator OM-89. All other nonantibiotic prophylactic strategies require more data, except for topical estrogen for postmenopausal women. For last-resort antibiotic prophylaxis, nitrofurantoin or fosfomycin trometamol are recommended. Guidelines for Latin America are currently being drafted, taking into account the unique ethnicity, availability of medicines, prevalence of antibiotic resistance, and healthcare practices found throughout the region.