Bacterial vaginosis (BV) is an infection of the vagina caused by excessive growth of bacteria. Common symptoms include increased vaginal discharge that often smells like fish. The discharge is usually white or gray in color. Burning with urination may occur. Itching is uncommon. Occasionally, there may be no symptoms. Having BV approximately doubles the risk of infection by a number of sexually transmitted infections, including HIV/AIDS. It also increases the risk of early delivery among pregnant women.
The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer thickens and then is shed during menstruation in humans and some other mammals, including other apes, Old World monkeys, some species of bat, the elephant shrew and the Cairo spiny mouse. In most other mammals, the endometrium is reabsorbed in the estrous cycle. During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. The speculated presence of an endometrial microbiota has been argued against.
Lactobacillus is a genus of gram-positive, aerotolerant anaerobes or microaerophilic, rod-shaped, non-spore-forming bacteria. Until 2020, the genus Lactobacillus comprised over 260 phylogenetically, ecologically, and metabolically diverse species; a taxonomic revision of the genus assigned lactobacilli to 25 genera.
The human microbiome is the aggregate of all microbiota that reside on or within human tissues and biofluids along with the corresponding anatomical sites in which they reside, including the gastrointestinal tract, skin, mammary glands, seminal fluid, uterus, ovarian follicles, lung, saliva, oral mucosa, conjunctiva, and the biliary tract. Types of human microbiota include bacteria, archaea, fungi, protists, and viruses. Though micro-animals can also live on the human body, they are typically excluded from this definition. In the context of genomics, the term human microbiome is sometimes used to refer to the collective genomes of resident microorganisms; however, the term human metagenome has the same meaning.
Vaginitis, also known as vulvovaginitis, is inflammation of the vagina and vulva. Symptoms may include itching, burning, pain, discharge, and a bad smell. Certain types of vaginitis may result in complications during pregnancy.
Vaginal discharge is a mixture of liquid, cells, and bacteria that lubricate and protect the vagina. This mixture is constantly produced by the cells of the vagina and cervix, and it exits the body through the vaginal opening. The composition, amount, and quality of discharge varies between individuals and can vary throughout the menstrual cycle and throughout the stages of sexual and reproductive development. Normal vaginal discharge may have a thin, watery consistency or a thick, sticky consistency, and it may be clear or white in color. Normal vaginal discharge may be large in volume but typically does not have a strong odor, nor is it typically associated with itching or pain. While most discharge is considered physiologic or represents normal functioning of the body, some changes in discharge can reflect infection or other pathological processes. Infections that may cause changes in vaginal discharge include vaginal yeast infections, bacterial vaginosis, and sexually transmitted infections. The characteristics of abnormal vaginal discharge vary depending on the cause, but common features include a change in color, a foul odor, and associated symptoms such as itching, burning, pelvic pain, or pain during sexual intercourse.
Dysbiosis is characterized by a disruption to the microbiome resulting in an imbalance in the microbiota, changes in their functional composition and metabolic activities, or a shift in their local distribution. For example, a part of the human microbiota such as the skin flora, gut flora, or vaginal flora, can become deranged, with normally dominating species underrepresented and normally outcompeted or contained species increasing to fill the void. Similar to the human gut microbiome, diverse microbes colonize the plant rhizosphere, and dysbiosis in the rhizosphere, can negatively impact plant health. Dysbiosis is most commonly reported as a condition in the gastrointestinal tract or plant rhizosphere.
Levilactobacillus brevis is a gram-positive, rod shaped species of lactic acid bacteria which is heterofermentative, creating CO2, lactic acid and acetic acid or ethanol during fermentation. L. brevis is the type species of the genus Levilactobacillus (previously L. brevis group), which comprises 24 species. It can be found in many different environments, such as fermented foods, and as normal microbiota. L. brevis is found in food such as sauerkraut and pickles. It is also one of the most common causes of beer spoilage. Ingestion has been shown to improve human immune function, and it has been patented several times. Normal gut microbiota L. brevis is found in human intestines, vagina, and feces.
Vaginal flora, vaginal microbiota or vaginal microbiome are the microorganisms that colonize the vagina. They were discovered by the German gynecologist Albert Döderlein in 1892 and are part of the overall human flora. The amount and type of bacteria present have significant implications for an individual's overall health. The primary colonizing bacteria of a healthy individual are of the genus Lactobacillus, such as L. crispatus, and the lactic acid they produce is thought to protect against infection by pathogenic species.
Oral microbiology is the study of the microorganisms (microbiota) of the oral cavity and their interactions between oral microorganisms or with the host. The environment present in the human mouth is suited to the growth of characteristic microorganisms found there. It provides a source of water and nutrients, as well as a moderate temperature. Resident microbes of the mouth adhere to the teeth and gums to resist mechanical flushing from the mouth to stomach where acid-sensitive microbes are destroyed by hydrochloric acid.
A cervical mucus plug (operculum) is a plug that fills and seals the cervical canal during pregnancy. It is formed by a small amount of cervical mucus that condenses to form a cervical mucus plug during pregnancy.
The vaginal flora in pregnancy, or vaginal microbiota in pregnancy, is different from the vaginal flora before sexual maturity, during reproductive years, and after menopause. A description of the vaginal flora of pregnant women who are immunocompromised is not covered in this article. The composition of the vaginal flora significantly differs in pregnancy. Bacteria or viruses that are infectious most often have no symptoms.
Lactobacillus jensenii is a normal inhabitant of the lower reproductive tract in healthy women. L. jensenii makes up 23% of vaginal microflora that is naturally occurring. It is also found on the skins of grapes at the time of their harvest. L. jensenii is sometimes used in producing fermented foods.
The Human Microbiome Project (HMP), completed in 2012, laid the foundation for further investigation into the role the microbiome plays in overall health and disease. One area of particular interest is the role which delivery mode plays in the development of the infant/neonate microbiome and what potential implications this may have long term. It has been found that infants born via vaginal delivery have microbiomes closely mirroring that of the mother's vaginal microbiome, whereas those born via cesarean section tend to resemble that of the mother's skin. One notable study from 2010 illustrated an abundance of Lactobacillus and other typical vaginal genera in stool samples of infants born via vaginal delivery and an abundance of Staphylococcus and Corynebacterium, commonly found on the skin surfaces, in stool samples of infants born via cesarean section. From these discoveries came the concept of vaginal seeding, also known as microbirthing, which is a procedure whereby vaginal fluids are applied to a new-born child delivered by caesarean section. The idea of vaginal seeding was explored in 2015 after Maria Gloria Dominguez-Bello discovered that birth by caesarean section significantly altered the newborn child's microbiome compared to that of natural birth. The purpose of the technique is to recreate the natural transfer of bacteria that the baby gets during a vaginal birth. It involves placing swabs in the mother's vagina, and then wiping them onto the baby's face, mouth, eyes and skin. Due to the long-drawn nature of studying the impact of vaginal seeding, there are a limited number of studies available that support or refute its use. The evidence suggests that applying microbes from the mother's vaginal canal to the baby after cesarean section may aid in the partial restoration of the infant's natural gut microbiome with an increased likelihood of pathogenic infection to the child via vertical transmission.
The placental microbiome is the nonpathogenic, commensal bacteria claimed to be present in a healthy human placenta and is distinct from bacteria that cause infection and preterm birth in chorioamnionitis. Until recently, the healthy placenta was considered to be a sterile organ but now genera and species have been identified that reside in the basal layer.
The uterine microbiome is the commensal, nonpathogenic, bacteria, viruses, yeasts/fungi present in a healthy uterus, amniotic fluid and endometrium and the specific environment which they inhabit. It has been only recently confirmed that the uterus and its tissues are not sterile. Due to improved 16S rRNA gene sequencing techniques, detection of bacteria that are present in low numbers is possible. Using this procedure that allows the detection of bacteria that cannot be cultured outside the body, studies of microbiota present in the uterus are expected to increase.
The human milk microbiota, also known as human milk probiotics (HMP), encompasses the microbiota–the community of microorganisms–present within the human mammary glands and breast milk. Contrary to the traditional belief that human breast milk is sterile, advancements in both microbial culture and culture-independent methods have confirmed that human milk harbors diverse communities of bacteria. These communities are distinct in composition from other microbial populations found within the human body which constitute the human microbiome.
Lactobacillus vaccines are used in the therapy and prophylaxis of non-specific bacterial vaginitis and trichomoniasis. The vaccines consist of specific inactivated strains of Lactobacilli, called "aberrant" strains in the relevant literature dating from the 1980s. These strains were isolated from the vaginal secretions of patients with acute colpitis. The lactobacilli in question are polymorphic, often shortened or coccoid in shape and do not produce an acidic, anti-pathogenic vaginal environment. A colonization with aberrant lactobacilli has been associated with an increased susceptibility to vaginal infections and a high rate of relapse following antimicrobial treatment. Intramuscular administration of inactivated aberrant lactobacilli provokes a humoral immune response. The production of specific antibodies both in serum and in the vaginal secretion has been demonstrated. As a result of the immune stimulation, the abnormal lactobacilli are inhibited, the population of normal, rod-shaped lactobacilli can grow and exert its defense functions against pathogenic microorganisms.
