Hello urologists, gynaecologists, primary care doctors and all of you who have to deal with urinary tract infections. Urinary tract infection management and prevention is one of the activities on a routine basis for all caregivers. This Newsletter intends to review the last recommendation for managing and preventing urinary infections. Our focus is reducing the number of infections, avoiding antibiotic use when not indicated to prevent resistance and reviewing the evidence about non-antibiotic measures to prevent infections. Scientific support of the evidence and practice guidelines recommendations will be the key to all the information in the Newsletter.

The focus of this issue is the revision of three articles. The first article reviews the current definition of uncomplicated and complicated urinary tract infections (UTIs). A proposal for modification bearing in mind the symptoms and the severity is reviewed. The microbiome's effect is also reviewed and how the modification in urine pH may be useful for preventing and managing urinary tract infections.

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The current definition for uncomplicated urinary tract infections (UTIs) is those that occur in healthy, nonpregnant women. Therefore, all cases of pyelonephritis and urinary tract infections in men should be considered complicated and managed with antibiotics according to the recommendations for complicated UTIs. The definition of complicated UTIs is more based on the existence of anatomical or functional abnormalities in the urinary tract more than on the presence of clinical signs of systemic infection. The revision states that the definition of complicated or uncomplicated UTIs must rely on the presence of signs and symptoms of systemic infections and also must consider the risk factors for ITUs. The main risk factors to be addressed are urinary catheters, neurological patients, urinary tract obstruction and renal transplantation.

The new proposal for definitions are:

• An Uncomplicated UTI is a localized urinary tract infection (ie, cystitis) without any sign of systemic infection in either sex. Risk factors predisposing to a severe clinical course or treatment failure might be present and should be considered and addressed.
• A complicated UTI is a systemic urinary tract infection with or without localized symptoms originating from any site in the urinary tract in either sex. Risk factors predisposing to a severe clinical course or treatment failure might be present and should be considered and addressed.

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The article focuses on the analysis of the human urine microbiome and its effects on urinary tract infections. Currently, it is clearly established that urine is not sterile. The urinary microbiome has relatively low biomass compared to other areas as the colon. The urine microbiome is also affected by the microbiome from the vagina, cervix periurethral skin, penis, pubic skin surfaces, and perineal area. It is proposed that Lactobacillus crispatus may act as a protective agent against the colonization of uropathogens in the urinary tract. Many factors influence microbial colonization of the urine such as pH, oxygen tension, osmolarity, nutrient availability, adhesion sites, and immune interaction. These factors may be considered as factors associated with the risk of urinary tract infections and preventive measures can be developed. For instance, urine pH can range from 5 to 8 and their regulations may have a potential effect on the microbiome characteristics. 

The relationship between urinary tract infections and the microbiome is discussed as there is evidence that both the infection itself and treatment strategies with antibiotics affect the urinary microbiome. Moreover, the studies on the microbiome have demonstrated that UTIs may be related to polymicrobial microorganisms isolation, frequently in elderly and immunocompromised populations. 

The modulation of the microbiome have been proposed as a possible route in the prevention and management of rUTIs. Lactobacilli may act as protective through the secretion of lactic acid, which modulates the local chemical environment. Moreover, several researches have been conducted in order to create models that allow the study of the immune system and its relation to the urinary microbiome. 

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The article is a systematic review of phytotherapeutic agents in patients with recurrent urinary tract infections (rUTIs). An important strength of the study is that only randomized controlled trials are included. The revision includes 12 randomized controlled trials with 1797 women. Several products are evaluated and heterogeneous dosages and prescription regimens are used. Therefore, general considerations about phytotherapy cannot be made. Phytotherapy can be used both as a therapeutical prescription in case of UTIs and for the prevention of UTIs.

Two studies evaluated the effect of phytotherapy at the moment of an episode of acute cystitis. One study using Chinese herbal medicine reported non-inferiority in comparison with antibiotics. However, it should be borne in mind that in many cases uncomplicated UTIs have an adequate resolution using symptomatic treatment. Another study by Cai et al. demonstrated that preparation with 400mg L-methionine, 100mg Hibiscus sabdariffa and 100mg Boswellia serrata reported good results in terms of clinical improvement and better quality of life in those who did not receive antibiotics. 

Several articles using cranberry products for the prevention of UTIs reported contradictory results. Several preparations such as beverages, capsules or sachets are included that may affect the amount of the product. Regarding adverse effects, all phytotherapeutics agents usually showed a good safety profile. 

The systematic review concludes that phytotherapeutic agents may be a valid option for the prevention and treatment of recurrent cystitis in women, with few associated adverse events. However, it is important to study the mechanisms of how all the products work and diana for treatment should be defined such as bacterial adhesion to urothelial cells, changes in urine pH or effect in the bacterial metabolism.