The vaginal flora is the natural bacterial colonization of the vagina. It maintains the vaginal environment and plays a role in pathogen defense.
What is the vaginal flora?
Compared to the intestinal flora, the vaginal flora is manageable. It is determined by two major groups of bacteria, Bacteroides and Lactobacillus. The pH of the flora is <4.5, which is in the acidic range. In the case of disease, the environment can shift and take on neutral to basic values. This allows pathogens to colonize the vagina. Vaginal flora that is out of balance promotes vaginal infections and often also leads to vaginal dryness, itching, burning, discharge or fishy vaginal odor. Often these symptoms are treated with excessive intimate hygiene. However, this approach destroys the vaginal flora permanently and thus aggravates the symptoms.
Anatomy and structure
The vaginal flora consists of obligate and facultative germs. The obligate germs are representatives of the normal site flora of the vagina. Obligate germs include Bacteroides and lactobacilli. The normal range of lactobacilli is 10⁴ to 10⁷ CFU per gram of vaginal secretion. Lactobacilli are capable of producing short-chain fatty acids, peroxides and various bacteriocins. While Bacteroides are part of the colonization resistance group, there are no known factors to date that suggest they play an important protective role in the vaginal tract. In a healthy vaginal tract, the so-called facultative germs always appear only temporarily. Facultative germs enter the vagina from the intestine or the urethra, for example. Facultative germs of the vaginal flora include: [[enterococci], E.coli, other enterobacteria, streptococci, staphylococci, Gardnerella, Candida albicans, other fungi and yeasts. However, the composition of the vaginal flora keeps changing throughout life. When estrogen levels are high, the sugar content in the vagina increases, so that the lactobacilli find optimal living conditions. Before puberty, the vaginal flora resembles the normal skin flora. This is also due to the fact that the ovaries do not yet produce estrogen, so the lactobacilli do not find food in the vagina. Only with the onset of estrogen production do lactic acid bacteria settle. The composition of the vaginal flora also changes during the monthly hormonal fluctuations in a woman’s cycle. Lactobacilli multiply particularly strongly during the follicular phase. The follicular phase is the first half of the menstrual cycle. After menopause, the vaginal flora changes again due to the drop in estrogen. The vaginal flora then resembles the skin flora again.
Function and tasks
The main function of the vaginal flora is to protect against pathogens. The healthy vaginal mucosa is densely colonized with lactobacilli and Bacteroides. These act as placeholders, so to speak, blocking the habitat for potentially pathogenic germs. Most pathogens also prefer a neutral or alkaline environment. In the vagina, however, the environment is acidic with a ph value below 4. Most germs do not settle under acidic conditions. Lactobacilli are responsible for maintaining the acidic environment. A special form of lactobacilli, the Döderlein rods (Lactobacillus acidophilus), process the exfoliated epithelial cells of the vagina into lactate. Lactate is lactic acid. However, the bacteria from the group of lactobacilli can not only produce lactic acid, they also produce bacteriocidal substances that are directly directed against pathogenic germs. In this sense, the mucous membrane of the vagina acts as a mechanical barrier. However, it is also an important part of the immune system and is closely associated with the immune defense of the intestine, with the so-called Gut associated lymphoid tissue (GALT). Thus, secretory immunoglobulin A can also be detected on the mucosa. However, the exact function of immunoglobulin in the vagina is still unclear.
Diseases
The vaginal flora can be negatively affected by many factors. Shower gel and bath additives, as well as many intimate care products, have a pH value that is much too high for the female intimate area. Cleansing products with disinfecting properties are also not suitable for cleaning the vagina. They do not differentiate between physiological and pathological germs and thus damage the flora in its entirety.The main cause of infections in the intimate area are chlorinated swimming pools. Chlorine has a very aggressive effect and damages the environment of the vagina. Tampons, pads and panty liners are also usually bleached with chlorine. They also contain other fragrances and perfumes that can further damage the vaginal flora. Another common source of infection is wiping after defecation. Women who wipe the anus from back to front run the risk of smearing bacteria from the stool toward the vagina. Intestinal bacteria can also be carried into the vagina during various sexual practices. A particular risk is the unprotected change from anal to vaginal intercourse. Immunological disorders such as stress, disturbed intestinal flora or immunosuppression due to medication also weaken the natural vaginal flora. The same is true for oral contraceptives, diabetes mellitus, topical contraceptives, and antibiotic or antifungal therapies. Vaginal dysbiosis can cause various symptoms and diseases. One common condition caused by vaginal dysbiosis is nonspecific colpitis. It is manifested by symptoms such as itching, redness, or thin fluid discharge with a fishy odor. Rarely, the inguinal lymph nodes are swollen. However, the consequences of long-term dysbiosis can be more drastic. For example, fertility decreases with vaginal dysbiosis. Miscarriages also occur more frequently. Vaginal dysbiosis is treated with antibiotics and flora-building preparations.
