Writing in the journal Microorganisms, researchers from APC Microbiome Ireland, University College Cork, Atlantia Food Clinical Trials, Church & Dwight, and Verb Biotics, reported the benefits of probiotic strain L. reuteri 3613-1 for UTI management.
“The ability of this strain to produce the bacteriocin reuterin was confirmed by HPLC, supporting the potential antimicrobial efficacy of this L. reuteri strain,” the researchers wrote. “Our findings suggest a potential benefit in delaying the onset of recurrent suspected UTIs in women. Further investigations with adequately powered sample sizes are warranted.”
Disruption of the vaginal microbiome
UTIs are a recurrent health condition impacting women and accounting for up to 20% of infections addressed in U.S. primary care facilities. Half of all women will experience at least one UTI over their lifetime, and it is estimated they cost the U.S. economy $1.6 billion per year.
Several pathogens can lead to the infection, including Gram-negative bacteria (e.g., Escherichia coli), Gram-positive bacteria (e.g., Staphylococcus saprophyticus), Gram-variable bacteria (e.g., Gardnerella vaginalis), and yeasts (e.g., Candida albicans). However, uropathogenic Escherichia coli (UPEC) accounts for a majority of UTIs.
“UPEC’s primary reservoir is in the gastrointestinal tract, and it has been shown that the excreted bacteria in stool can make their way into the urethra and bladder,” the researchers noted. “This highlights the importance of preventing the proliferation of UPEC, which can be sourced from both vaginal and fecal bacteria, and emphasizes the need for an integrated approach to UTI management.”
The vaginal ecosystem is typically populated by numerous Lactobacillus species that help maintain an acidic pH and create antimicrobial compounds, establishing a healthy vaginal microbiome and a defense against pathogens.
“Disruption of the established vaginal microbiome, often associated with a reduction in Lactobacillus species, promotes a more favorable environment for pathogenic bacteria, increasing the risk of UTIs,” the researchers explained.
Oral and topical antibiotics are usually administered to treat UTIs, but they can disrupt the vaginal microbiome balance and increase the risk of more infections as well as encouraging the development of drug-resistant pathogens.
Although probiotics can promote urinary and vaginal health, clinical trials have shown their efficacy is inconsistent. However, scientists have identified L. reuteri 3613-1 as a potential probiotic candidate to suppress UTIs.
Study details
The randomized, double-blind, placebo-controlled clinical trial assessed 130 women aged 18 to 65 who took daily oral supplementation with L. reuteri for 24 weeks. Specifically, the scientists explored the antimicrobial properties of Limosilactobacillus reuteri 3613-1 and its ability to improve UTI outcomes in women with recurrent uncomplicated UTIs.
“In vitro assays showed that L. reuteri 3613-1 inhibited the growth of Escherichia coli isolates and proved superior inhibition of Gardnerella vaginalis and Candida albicans compared with a comparator L. reuteri strain, supported by confirmed reuterin production and genomic profiling,” the researchers explained.
“While the proportion, frequency, and intensity of confirmed UTIs did not differ significantly between groups, L. reuteri 3613-1 delayed the onset of the first UTI, reaching significance in participants with suspected while unconfirmed UTIs.”
They added that L. reuteri 3613-1 shows promise as a probiotic candidate with antimicrobial activity and may delay symptom onset in women susceptible to recurrent UTIs, though further investigation in larger studies is still needed.
Scientists identified L. reuteri 3613-1 from a library of over 6,000 lactic acid bacteria in the Arm & Hammer brand research library as unique because of its ability to produce antimicrobial metabolites. The strain produces reuterin, a potent antimicrobial compound that inhibits vaginal and urinary pathogens up to 90% more effectively than other strains. It can be applied across key delivery formats, integration into powder mixes, cultured products and capsules.
Source: Microorganisms. doi: 10.3390/microorganisms14030615. “Limosilactobacillus reuteri 3613-1 Delays Onset of Unconfirmed Urinary Tract Infections in Otherwise Healthy Women.” Authors: V. Turpin et al.
