Introduction:
Urinary tract infections (UTIs) are the most common bacterial infections among patients with polyclinics. UTIs often recur, with a 24 percent chance of recurrence after the first episode in healthy women aged 18 to 29. Key risk factors for women aged 18 to 39 include sexual activity and previous UTI history. Recurrent UTIs are defined as three episodes in the last year or two in the last six months.
Treating UTIs with antibiotics can lead to resistance among uropathogenic microorganisms, which is increasingly common. Repeated antibiotic use in women with recurrent UTIs can foster resistance and negatively impact normal microbial flora. Consequently, there is a growing interest in antibiotic-free preventive approaches, particularly for recurrent UTIs.
Among these alternatives, probiotics show promise. As probiotic treatments become more common for UTIs, a detailed examination of the urinary microbiome is essential.
What Is an Urinary Tract Infection?
Urinary tract infections (UTIs) are infections of the kidneys, ureters, urethra, or bladder caused by bacterial colonization. They are among the most common bacterial infections and can lead to serious complications, including strictures, abscesses, fistulas, bacteremia, sepsis, pyelonephritis (inflammation of the kidney due to a type of UTI), and kidney dysfunction. Mortality rates can reach up to one percent in men and three percent in women due to pyelonephritis, with one in two women experiencing a UTI at some point in their lives. Elderly individuals are particularly prone to asymptomatic UTIs, with a prevalence of 30 percent in women and 10 percent in men annually.
What Is the Microbial Flora of the Urinary Tract?
The human microbiome has garnered significant interest recently, with various studies exploring the roles of complex microbial communities in different diseases. While extensive research exists on the microbiota of the skin, mouth, vagina, and intestines, urinary microbiota (UM) has not been studied as thoroughly, largely because urine was traditionally considered sterile in healthy individuals.
Recent advances in 16S rRNA sequencing and quantitative urine culture techniques (EQUC) have revealed the presence of aerobic and anaerobic bacteria in the urinary systems’s normal flora. These urinary bacteria play a crucial role in maintaining the health and balance of the urinary system.
The concentration of bacteria in the urinary microbiome can vary based on sex, urine collection method, and the analytical technique used. Commonly observed species include Lactobacillus and Streptococcus, both lactic acid bacteria that protect against urogenital pathogens. Less frequently found strains include Alloscardovia, Burkholderia, Jonquetella, Klebsiella, Saccharofermentans, Rhodanobacter, and Veillonella. The method of urine collection– such as midstream, first void, suprapubic aspiration, or catheterization– can influence UM profiles.
Despite various bacterial species in the urinary system, these do not typically lead to chronic UTIs. It is suggested that host factors significantly influence the colonization of these organisms, allowing hosts to maintain a balance with non-harmful microorganisms. The relationship between hosts and bacteria raises questions about co-evaluation. Notably, recurrent UTIs are more common in children of women with a history of recurrent episodes, which may result from genetic predisposition or bacterial transfer during childhood or birth.
What Are Probiotics and Their Role in Preventing Urinary Tract Infections?
Probiotics, whether in supplements or food products, have become a key focus in the functional foods market due to their potential health benefits. The term probiotic means “ for life”. Common strains of probiotics, primarily from Bifidobacterium and Lactobacillus, contribute to health by detoxifying pollutants, synthesizing vitamins, and fermenting fiber. They also help prevent pathogenic bacteria, enhance gut microbiota, and improve nutrient absorption. Probiotics can be consumed through fermented foods or supplements, enriching the nutritional profile and functional properties of various products.
Probiotics to Prevent Urinary Tract Infections:
To restore vaginal microflora, probiotics containing Lactobacillus species are essential for preventing and treating genitourinary infections. Their mechanisms include acidifying the mucosal surface, inhibiting pathogen adhesion, producing beneficial substances like vitamin immunomodulators, and working synergistically with the host’s immune system.
Certain Lactobacillus species generate hydrogen peroxide and biosurfactants, which help acidify the vaginal environment and exhibit micro biomimetic regulatory effects. These characteristics make Lactobacillus the preferred choice for preventing and treating urogynecology infections. Lactobacilli effectively prevents the adherence, growth, and colonization of uropathogenic bacteria, with healthy populations demonstrating strong inhibition of E.coli. Additionally, antibiotic treatments can lead to increased drug resistance and compromise the natural defenses of the urinary system, making it more susceptible to infections.
Most UTIs are caused by uropathogenic E.coli. Antibiotics used to treat these infections can decrease Lactobacilli levels in the urinary system, potentially leading to antibiotic resistance and compromising the natural barrier against infections.
Zuccotti et al. suggested that probiotics could serve as a promising alternative to antibiotic therapy due to their ability to bind to uroepithelial cells, inhibit pathogenic growth, and secrete biosurfactants. They also noted that oral Lactobacillus therapy can lead to colonization in the urinary tract after initially colonizing the intestines.
The rationale for oral probiotic use lies in the understanding that pathogens causing urogenital infections often spread from the rectum to the perineal region and then to the vagina. If pathogenic bacteria can travel this route, so can Lactobacillus, a crucial component of vaginal health. Clinical studies have shown that oral administration of Lactobacillus can positively impact vaginal health.
Can Probiotics Cure Urinary Tract Infections?
Probiotics have been investigated for various diseases, showing promise in preventing and treating conditions like dental caries, GI issues, and antibiotic-associated diarrhea. In urology, probiotics have been studied primarily in small trials, focusing on recurrent urinary tract infections (RUTIs), enteric hyperoxaluria, and neurogenic bladder conditions. Encouraging results include the use of non-pathogenic E.coli for bladder instillation, which reduced RUTI rates in neurogenic bladder patients. Current trials are exploring oral and topical probiotics for RUTIs, with some showing promise in reducing infection rates. Probiotics represent a significant alternative strategy in managing chronic infections and mitigating antibiotic-related side effects, particularly in the context of RUTIs, an urgent healthcare issue due to rising antibiotic resistance.
Conclusion:
UTIs significantly impact the quality of life, and while antibiotic prophylaxis is effective, it can lead to increased resistance among uropathogens. Interest in non-antibiotic prevention methods, particularly probiotics, has grown due to patient preferences for natural treatments and physician concerns about antibiotic resistance. Probiotics remain a popular choice among patients due to their safety and better tolerance compared to antibiotics.
