The article is a clinical research including 33 female patients who were divided in two group according to the treatment after an episode of urinary tract infection. 23 patients received L-methionine daily with a follow-up period of 26 months and 10 patients received nalidixic acid with a follow-up period of 21 months . L-methionine treatment was associated with decreased load of the uroepithelial cell to 95.6 +/- 73.6 to 51.2 +/- 56.4 bacteria per cell, and a decrease from 74.0 +/- 88.4 to 34.4 +/- 37.8 bacteria per cell in the groups with nalidixic acid. Moreover, no acute infection occurred during L-methionine treatment. All parameters of inflammation (leucocyte count, C-reactive protein, blood sedimentation rate, alpha 2-globulin concentration) were in the normal range; no impairment of renal function was observed.

Authors conclude that L-methionine is an adequate tool to prevent reinfection with chronic urinary tract infection. According to the results, it is suggested that the therapeutic effect of L-methionine is bases due to its influence on bacterial cytoadherence. Therefore, L-methionine is an alternative to antibiotics in the prevention of urinary tract infections, with lower side effects and no potential risk factors of antimicrobial resistance associated to antibiotic treatment.

Recipients with a kidney transplant have a higher risk of urinary tract infections. The occurrence of recurrent urinary tract infections may be associated with hospitalizations and also affect the incidence of acute rejection and decrease the graft and survival rate. The study is a retrospective research including 112 kidney transplant with recurrent urinary tract infections, evaluating several preventive strategies. 39 patients received 50ml twice daily of cranberry juice, 25 patients received L-methionine 500mg three times per day, 18 patients received L-methionine and cranberry juice and 30 controls did not received prophylaxis. The mean duration of prophylaxis was 22.1 +/- 18.7 months.

The incidence of urinary tract infections decreased 58.3% in the groups with active prophylaxis and the presence of pyuria/nitrituria disappeared in 42.4% of those with a positive dipstick. Cranberry reduced the annual number of UTI episodes by 63.9% from 3.6 +/- 1.4 to 1.3 +/-1.3 per year and and, L-methionine by 48.7% from 3.9 +/-1.8 to 2.0 +/ 1.3 per year. The combination of cranberry and L-methionine significantly reduced the number of UTI episodes from 3.1 +/- 1.3 to 1.1 +/- 1.1 per year. Authors concluded that both cranberry juice and L-methionine successfully reduced the incidence of UTI in recipients with a renal transplant.

The article is a revision of the effect of urinary microbiome and novel therapies for urinary tract infections. It is demonstrated that urine is not sterile. Currently several studies are carried out evaluating how changes and imbalances of the microbiome in urinary tract infections and other diseases such urinary incontinence, pelvic pain and how these entities also affects the microbiome. The review also analyses how urine pH affect the “called” healthy state with pH 4.6 to 7 and urobiome dominates by Lactobacillus, Prevotella, Shigella and Corynebacterium. On the other hand, in the UTI state the urine pH of 7.8 and 9 is associated with increased abundance of common uropathogens such as E. coli, Enterococcus and Staphylococcus and a subsequent decrease in Lactobacillus.

Novel therapies in the prevention and management of urinary tract infections focus on bacterial interference such us probiotics, antimicrobial peptides, bacteriocins, and bacteriophage. The regulation of urine pH may play a role in the prevention of urinary infections that can be demonstrated by the effect of several probiotic that produce lactic acid and hydrogen peroxide that through pH regulation, affect the adherence to uroepithelial cells, downregulates NF-KB, P, and Type 1 fimbriae. Therefore, the urine pH may affect the occurrence of urinary tract infections. Moreover, the regulation of urine pH may also provide a potential beneficial effect.