Urinary tract infections (UTIs) are among the most common bacterial diseases, affecting an astonishing 150 million individuals worldwide yearly. UTIs are prevalent bacterial infections that affect over 150 million people globally, with a significantly higher occurrence in women and 50-60% of whom experience a UTI at some point in their lives. The frequent use of antibiotics to treat UTIs can lead to antibiotic-resistant bacteria and reduce beneficial gut bacteria, potentially causing recurrent UTIs. A recent study published in the Nutrients journal explores the link between gut microbial imbalances and risk factors in women with a history of UTIs.
Research has shown that gut microbial dysbiosis can contribute to kidney diseases and UTIs through the intestine-kidney axis. Most UTIs are caused by uropathogenic Escherichia coli (UPEC), Klebsiella spp., Enterobacter spp., Staphylococcus spp., Proteus spp., and Enterococcus spp. Recurrent UTIs (rUTIs) are often associated with UPEC strains, which have genetic differences from commensal E. coli, including genes for toxins, flagella, surface polysaccharides, and iron acquisition factors. E. coli from the intestine can migrate to the urinary tract, leading to UTIs. Studies have indicated that gut microbial dysbiosis exacerbates the growth of pathogenic bacteria that can migrate to the urinary tract, supporting the gut microbiota-UTI axis theory.
In this study, the researchers included women aged 18-45 who had been diagnosed with UTIs in the past five years. Those with two or more symptomatic UTI episodes in the past six months or more than three UTIs in the past year were classified as having rUTIs. Uropathogenic bacteria were isolated from their urine samples. Another group consisted of women who had not had a UTI in the past 12 months but had a history of sporadic, non-recurrent UTIs (nUTIs).
Participants with comorbidities such as renal lithiasis, immunosuppressive states, neurological conditions, urinary tract surgeries, constipation, and diabetes were excluded to avoid confounding factors. The selected participants underwent a fecal dysbiosis test, with dysbiosis defined by a Flora index level of six or higher. They also completed a questionnaire on their nutritional health, lifestyle habits (smoking, alcohol, and coffee consumption), and medical history, including antibiotic resistance due to repeated treatments.
The study found that over 70% of women with intestinal dysbiosis developed UTIs. An association was shown between intestinal dysbiosis and recurrences of UTI. Increased body weight was associated with intestinal dysbiosis. Also, the lack of knowledge regarding the risk of using antibiotics and the benefits of probiotics was associated with both dysbiosis and recurrences of urinary tract infections. Frequent antibiotic use can lead to multi-resistant microorganisms, as confirmed by antibiotic sensitivity tests.
The study identifies microbial dysbiosis and antibiotic resistance as key risk factors for rUTIs. Increased consumption of energy drinks and carbonated water, along with low water intake, can influence rUTI incidence. Prebiotics and probiotics can help restore intestinal microbiota and prevent UTIs. Maintaining a healthy lifestyle with limited antibiotic use may protect women from rUTIs. The findings highlight that antibiotic therapies significantly reduce beneficial gut bacteria, promoting the uncontrolled growth of pathogenic E. coli strains.
References
- Ruța F, Pribac M, Mardale E, Suciu S, Maior R, Bogdan S, et al. Associations between Gut Microbiota Dysbiosis and Other Risk Factors in Women with a History of Urinary Tract Infections. Nutrients. 2024 Jan;16(11):1753.
- Mocanu A, Bogos RA, Lazaruc TI, Trandafir LM, Lupu VV, Ioniuc I, et al. Exploring a Complex Interplay: Kidney–Gut Axis in Pediatric Chronic Kidney Disease. Nutrients. 2023 Aug 17;15(16):3609.