{"id":2655,"date":"2021-01-22T09:38:05","date_gmt":"2021-01-22T09:38:05","guid":{"rendered":"https:\/\/www.danielleal.pt\/?p=2655"},"modified":"2021-01-23T09:43:23","modified_gmt":"2021-01-23T09:43:23","slug":"the-relationship-between-the-vaginal-microbiota-and-urinary-tract-infections","status":"publish","type":"post","link":"https:\/\/danielleal.pt\/en\/the-relationship-between-the-vaginal-microbiota-and-urinary-tract-infections\/","title":{"rendered":"The Relationship between the Vaginal Microbiota and Urinary Tract Infections"},"content":{"rendered":"

Urinary tract infections (UTIs) are quite common in females. Instead of a linear mechanism of infection, there seems to be a strong influence of the microbiota on the process, which we will explore in this article.<\/span><\/p>\n

Before the widespread use of DNA amplification techniques and microorganisms characterization, microbiology was based exclusively on identifying of infectious agents by direct visualization or culture. In the specific case of UTIs, the presence of symptoms associated with the isolation of pathogenic bacteria in the urine culture confirms the diagnosis. <\/b>Ideally, the clinician can then pick the correct antibiotic according to the bacteria sensitivities. This has been the paradigm of Infectious Diseases, which has saved many lives and should not be discarded at all.<\/span><\/p>\n

However, as we learn more about the bacteria that inhabit our bodies, we realize that the vast majority of them \u201cwork\u201d in our favor (symbiotic\u00a0 <\/span>relationship). <\/b>Hence all the enthusiasm for scientific research around the microbiota. The main reservoir of bacteria in the body is present in the intestine, but other places, such as the lungs, oropharynx, and vagina, are also important and have different characteristics. The future of medicine will be to promote the balance of the several ecosystems in the body, instead of resorting only to\u00a0 <\/span>antibiotics to eliminate pathogens.<\/b> We will explore how symbiotic agents can make the terrain less favorable for pathogenic species.<\/span><\/p>\n

How frequent are UTIs?<\/span><\/strong><\/p>\n

The bladder is one of the most frequent infection sites in the human body, especially in women, for anatomical reasons. Between 50-60% of adult women have at least one UTI during their lifetime <\/b>(1<\/span><\/a>). About 1% of the world’s female population (70 million women) suffer more than six UTIs per year, which significantly affects their quality of life and leads to multiple antibiotics courses.<\/span><\/p>\n

What is the cause of UTI in women?<\/span><\/strong><\/p>\n

The prevailing theory is based on the colonization of the vaginal opening (orifice) by bacteria from the fecal flora (Escherichia coli, Klebsiella pneumoniae, etc.). These bacteria can then ascend through the urethra, reaching the bladder. Women have a much shorter urethra, which makes this movement easier. Usually, the infection is limited to the bladder, but it can sometimes reach the kidney, causing a more severe situation (pyelonephritis).<\/b><\/span><\/p>\n

\"fig1_blog_daniel-leal_artigo_infecao_urinaria_EN\"<\/p>\n

Fig. 1 – Vaginal colonization and ascension of bacteria through the urethra, causing UTIs.<\/span><\/h4>\n

 <\/p>\n

Recently, the urinary microbiota has also been the subject of study, and it was found that urine is not sterile, even in the absence of infection. There seems to be a convergence of different types of microbiota – intestinal, vaginal, and urinary – in the bladder, conditioning the possible development of infections. (2<\/span><\/a>)<\/span><\/p>\n

What do we know about the vaginal microbiota?<\/span><\/strong><\/p>\n

Unlike the intestinal microbiota, where the diversity of bacteria is a sign of a healthy ecosystem, in the vagina the situation is different. A<\/b> healthy vaginal ecosystem is composed of more than 90% of bacteria belonging to the Lactobacillus <\/i>genus. <\/b>Within the genus, the species Lactobacillus crispatus<\/i> is the most beneficial. The greater the diversity of bacteria in the vagina, the greater the tendency for imbalance and the development of several infections. <\/b>(3<\/span><\/a><\/span>, 4<\/span><\/a><\/span>) This is the case of bacterial vaginosis, where there is a decrease in\u00a0Lactobacilli<\/i>, and an increase in the population of\u00a0Gardnerella vaginalis<\/i>\u00a0and other anaerobic bacteria (they do not survive in the presence of oxygen).<\/span><\/p>\n

What is the role of Lactobacillus in preventing UTI?<\/span><\/strong><\/p>\n

Lactobacilli<\/i> promote a healthy vaginal environment and decrease UTIs through the following mechanisms: (5<\/span><\/a>)<\/span><\/p>\n