The human body is the perfect place for bacteria to live. We can say that our body contains at least the same number as human cells: approximately 39 trillion. Seems like a lot, doesn’t it? These high numbers lead us to think that the microorganisms that inhabit us play an important role.

The set of bacteria – the microbiota – that inhabit some areas of the body, such as the intestines, has been extensively studied. Its composition and role in health and disease are well known.

But what to say about the urinary microbiota, so far quite unknown? Researchers from the University of Granada, Almería and the Virgen de las Nieves University Hospital wanted to answer that question by analyzing the information available in this new field of study.

The urinary microbiome: the great unknown

It has long been believed that the urine of healthy people is sterile and that any bacteria in it can cause urinary tract infections. The idea is supported by the use of bacterial culture techniques that allow the growth of only a very limited number of microorganisms.

But the era of genomics, the Human Microbiome Project and the development of new massive sequencing tools made it possible to identify the microbial community in the urinary tract of healthy individuals as well.

Therefore, we know that this ecosystem differs according to gender: most of the bacterial genus is in women Lactobacilluswhile the urinary microbiota of men, much less studied, is dominated by genera Corynebacterium and streptococcus.

Other factors such as age and hormone levels also cause changes. As we age, there is a reduction Lactobacillus and Gardnerella and genres like mobiluncus, oligella and Porphyromonas.

In addition, many species of the urinary tract also inhabit the vagina and intestines. Consequently, changes in these two bacterial communities translate into changes in the urinary microbiota.

The main genus of bacteria in women is Lactobacilluswhile the urinary microbiota of men is dominated by genera Corynebacterium and streptococcus. Shutterstock / OrangeVector

Its role in diseases of the urinary system

Traditionally, urinary tract infection was associated with isolated pathogenic bacteria such as Escherichia coli. However, new research has made it possible to identify multiple origins; that is, it is more a consequence of the deterioration of the microbiota than the invasion of a specific pathogen. In general, a reduction of Lactobacillus – the majority gender in healthy individuals – appears to increase the frequency of urinary tract infections.

Certain changes in the urinary microbiota are also associated with other pathologies such as urothelial carcinoma and prostate cancer. An increase in the number of bacteria that secrete substances involved in inflammatory processes could promote the development of these diseases.

Also, mechanical problems such as urinary incontinence can be influenced by changes in the respective bacterial community. A reduction in the number of bacteria in healthy individuals increases the population of pathogenic microorganisms that, among other mechanisms, release molecules that stimulate bladder muscle contraction.

These are just some of the diseases related to the state of the urinary microbiota. The findings therefore highlight the importance of taking this into account in the prevention, diagnosis and treatment of these diseases.

A new area of ​​study for new therapies

Today, most urinary tract infections are treated with broad-spectrum antibiotics. However, the increasingly frequent appearance of bacteria resistant to these drugs indicates the importance of more precisely identifying the responsible agents. It is about improving the effect of medicines and avoiding the deterioration of microbial communities present in the human body.

Another solution is to develop new therapies beyond antibiotics. Among them are probiotics, which have become increasingly popular in recent years. Intravaginal or oral administration of some strains Lactobacillusas L. crispatus and L. acidophilusit enabled the long-term colonization of urinary microbiota and a reduction in the frequency of infections.

Other therapies based on current knowledge about urinary microbiota are fecal microbiota transplantation and the use of bacteriophages, viruses that infect and destroy bacteria. In both cases, the prevalence of urinary tract infections and the presence of causative bacteria, including those with pronounced resistance to antibiotics, decreased.

Nutrition for maintaining a healthy microbiota

But before we get to this point, our habits can also contribute to keeping the microscopic population that colonizes the urinary tract healthy and stable. As in the case of other microbiota, diet plays an important role here. Therefore, moderate consumption of products containing blueberries – or their juice – and fermented foods rich in probiotics can help maintain bacterial balance and suppress pathogenic bacteria.

Although there is still a long way to go until it is fully understood, the urinary microbiome may be the key that allows us to develop new preventive, diagnostic and therapeutic strategies for diseases affecting the urinary system.