By Carol A. Kemper, MD, FACP
Source: Gupta V, Mastromarino P, Garg R. Effectiveness of prophylactic oral and/or vaginal probiotic supplementation in the prevention of recurrent urinary tract infections: A randomized, double-blind, placebo-controlled trial. Clin Infect Dis 2024;78:1154-1161.
About half of women experience urinary tract infection (UTI) during their lifetime, and around 20% to 25% will experience recurrent UTI (defined as three or more UTIs in a 12-month period or two UTIs in a six-month period). Those with two UTIs in a six-month period have a 50% chance of a third UTI. Repeated courses of antibacterials distort both intestinal and vaginal flora, further increasing the risk of urinary infection.
This double-blind, placebo-controlled study examined the risk of recurrent UTI in 174 premenopausal women with a history of recurrent UTI who received oral and/or vaginal probiotics. The women were randomized to four treatment groups: oral and vaginal placebo (group P), oral probiotics with vaginal placebo (group O), oral placebo and vaginal probiotic (group V), and both oral and vaginal probiotics (group OV). The products were used for eight days every month for four months. Oral probiotics consisted of oral lactic acid and bifidobacteria (Visbiome and Florimax; one capsule each daily), and the vaginal probiotic was Lactobacillus (either FloraBalance or EvaNew; one capsule daily). Clinical UTI was defined by symptoms, whereas microbiological UTI was based on a culture with ≥ 105 colony forming units of a single pathogen. Patients were seen monthly for six months with clinical and microbiological assessment (both urine culture and vaginal smear), and then were phoned monthly for six months to assess symptoms. Those who were symptomatic were seen in person.
The risk of UTI at the end of four and 12 months was significantly different among the four groups. At four months, the incidence of UTI for groups P, O, V, and OV, respectively, was 70.4%, 61.3%, 40.9%, and 31.8%. At four months, the risk of UTI in each of the intervention groups was lower than group P, and the risk of UTI in groups V and OV was significantly lower than in groups P and O (P < 0.05). In addition, the time to first symptomatic UTI for each of the four groups (P, O, V, and OV), respectively, was 69, 72, 124, and 142 days (P < 0.001). At 12 months, the incidence of UTI for groups P, O, V, and OV, respectively, was 95.5%, 77.3%, 61.4%, and 54.5%. Vaginal Lactobacillus colony counts were significantly higher in the OV group than in the other groups (P = 0.008). Further, within groups analysis at four months showed significant reductions in vaginal Escherichia coli colony counts in the V and OV groups compared with the other two groups.
These data indicate that a relatively simple, well-tolerated intervention with either vaginal probiotic or oral and vaginal probiotic, used for eight days every month for four months, significantly improved vaginal flora and reduced the frequency of recurrent UTI. The infection-free duration more than doubled in those using both oral and vaginal probiotic compared to those using none. By 12 months, the risk of recurrent UTI in those using both oral and vaginal probiotic was nearly halved compared with those using oral/vaginal placebos.
Treatment of recurrent UTI in women often feels like you are spinning your wheels, with little to offer except repeated courses of antibiotics. Anything that limits the frequency or time to recurrence is welcome. Similar studies in post-menopausal women are needed.
Carol A. Kemper, MD, FACP, is Medical Director, Infection Prevention, El Camino Hospital, Palo Alto Medical Foundation.
About half of women experience urinary tract infection (UTI) during their lifetime, and around 20% to 25% will experience recurrent UTI (defined as three or more UTIs in a 12-month period or two UTIs in a six-month period). Those with two UTIs in a six-month period have a 50% chance of a third UTI. Repeated courses of antibacterials distort both intestinal and vaginal flora, further increasing the risk of urinary infection.
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