Levilactobacillus brevis | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Bacillota |
Class: | Bacilli |
Order: | Lactobacillales |
Family: | Lactobacillaceae |
Genus: | Levilactobacillus |
Species: | L. brevis |
Binomial name | |
Levilactobacillus brevis (Orla-Jensen 1919) Zheng et al. 2020 [1] | |
Synonyms | |
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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. [1] [2] 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.
L. brevis is one of the major lactobacilli found in tibicos grains, used to make kefir, but Lentilactobacillus species are responsible for the production of the polysaccharide (dextran and kefiran) that forms the grains. [3] Major metabolites of L. brevis include lactic acid and ethanol. Strains of L. brevis and L. hilgardii have been found to produce the biogenic amines tyramine and phenylethylamine.
E.B.Fred, W.H. Peterson, and J.A. Anderson initially discovered the species in 1921 and the it was categorized based on the ability to metabolize certain carbon compounds such as the sugars. This early study showed that this can produce acetic acid, carbon dioxide and large amounts of mannitol. Mannitol which is another carbon source that can be used to produce lactic acid. [4]
L. brevis has been shown to actively transport glucose and galactose. When fructose was used as a carbon source there was only some growth and L. brevis was able to partially metabolize the fructose to mannitol. There are some strains that poorly metabolize glucose but prefer disaccharides as carbon source.
By using the fermentation pathway the result is lactic acid and acetic acid. [5] It appears that under high temperature conditions, 50°C and in acidic environments the survival of this bacteria is longer than most bacteria under acidic conditions, the bacteria can live about 45 minutes. [6]
Antibiotic resistance is acquired through conjugation, a method of bacterial reproduction. Conjugation permits a sharing of DNA allowing the bacterium to identify various antibiotics through exposure and this information is passed down through replication between bacteria.
L. brevis produces more organic acids, specifically acetic acid and ethanol. This means that this bacterium produces an increased acidic environment and alcohol. Growth conditions all depend on the location of the bacterium within the intestines. It does seem that they are unable to significantly replicate in anaerobic environments. [5]
L. brevis is heterofermentative and uses the phosphoketolase pathway to metabolize pentoses and hexoses. [7]
L. brevis is found in food such as sauerkraut and pickles. It is also one of the most common causes of beer spoilage. The hop, which is an antimicrobial bitter flavoring agent in beer, fails to suppress some strains of L. brevis because they produce a transporter that pumps the active agents of hops out of the bacterial cell. [8] [9] L. brevis is one of the major lactobacilli found in tibicos grains (or the kefir grains in water), and has been identified as the species responsible for the production of the polysaccharide (dextran) that forms the grains. Major metabolites of L. brevis include lactic acid and ethanol. Strains of L. brevis and L. hilgardii have been found to produce the biogenic amines tyramine, which is found by the fermentation metabolic pathway and is commonly found in spoiled or fermented foods and phenylethylamine, which is found in chocolates but can also produce a fishy odor in other foods.
As a bacterium there are some physical attributes of L. brevis that are common for all bacteria. Gram-positive bacteria consists of an external plasma membrane, followed by periplasmic space and finally a peptidoglycan layer, which faces the interior of the bacteria. The external plasma membrane is very important for bacteria because this is how cells recognize the possible pathogenesis of the bacteria. Peptidoglycan is also called murein and is made up of a series of sugars and amino acid monomers. Within gram-positive bacteria the peptidoglycan layer is much thicker than gram-negative bacteria. The actual lattice that comprises peptidoglycan is referred to as the S-layer; this lattice is linked to the peptidoglycan layer. However, the S-layer is normally lost when processing the bacteria under laboratory conditions, which can affect measuring adhesion. When the S-layer is dissolved with high concentration levels of substances that break down hydrogen bonds the S-layers have a survival time of about 20 minutes with each generation. L. brevis contains approximately two promoters within this area, meaning that there is significant transcription of the S-layer by high levels of transcribing of the sIpA gene. [10] SipA is a gene that has been found to aid in the coding for the production of murin (peptidoglycan) within the bacteria. The purpose of transcription is to copy DNA into a mRNA, which is used to create proteins. The promoter is used during transcription to identify the appropriate location to begin transcribing. Within probiotics it is actually the S-layer that attaches to the cellular wall of the gastrointestinal tract. [11]
Ingestion of probiotics has been shown to improve human immune function, and L. brevis has been patented several times. L. brevis has been shown to survive in the gastrointestinal tract in humans and can therefore be used as a probiotic. Currently the bacterium does not have the ability to convert milk to yogurt however, they are appropriate to be used as an alternative to other probiotics in yogurts. Within the geriatric population use of the bacteria in milk has been shown to increase cellular immunity. Dietary probiotic supplementation enhances natural killer cell activity in the elderly (an investigation of age-related immunological changes). L. brevis is considered appropriate for probiotic use because there is significant growth at pH 4–5, particularly pH=5 is normally the appropriate range for milk and yogurts. [12] [13]
This section needs more reliable medical references for verification or relies too heavily on primary sources .(December 2012) |
There are significant vaginal bacteria that are found within the vagina and L. brevis is included in this microbiome, which is a collection of various bacteria. The bacteria collaborate on protecting the vagina and vaginal maintenance. Women of childbearing ages have a significant amount of L. brevis and this is normally found in a healthy vagina. [14] For some illnesses or disruptions of the vagina this bacteria can be used in aiding to restore the microbiome. Most lactobacilli have been found useful in preventing urinary tract infections. The efficiency in which a bacterium can defend the body is: [15]
During normal childbirth, it appears that newborns after a period of days receive transmission of L. brevis from the mother. It appears that the transmission occurs through breast feeding or through natural child birth. [16] In infants, this resistance is also helpful with protecting the gut against various bile and acids. Helicobacter pylori, which is a common gut pathogen in humans, studies have shown that certain strains of L. brevis are successful at combating this pathogen.
Vaginosis is the most common form of bacterial infection this is commonly diagnosed as a yeast infection or trichomoniasis, which is a sexually transmitted parasite commonly acquired during intercourse. L. brevis along with Lactobacillus jensenii has been shown to produce high levels of hydrogen peroxide which may be able remediate the bacterial vaginosis pathogenesis. [17] L. brevis is a commonly used ingredient in pharmaceutical materials used to treat vaginosis. An evaluation of clue cells is one method of assessing vaginosis; this assessment is performed by mounting clue cells and vaginal discharge onto a slide then adding sodium chloride followed by a microscopic assessment which involves bacteria identification. [17]
In addition to surviving within the gut of an organism, L. brevis can also act to inhibit the pathogenic effects of certain gut pathogens and can also proliferate in the presence of additional bacteria. Some strains are resistant to certain antibiotics, specifically erythromycin and clindamycin. [18] This antibiotic resistance may be helpful in maintaining a healthy gut microbiome when taking prescribed antibiotics.
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.
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.
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.
Probiotics are live microorganisms promoted with claims that they provide health benefits when consumed, generally by improving or restoring the gut microbiota. Probiotics are considered generally safe to consume, but may cause bacteria-host interactions and unwanted side effects in rare cases. There is some evidence that probiotics are beneficial for some conditions, such as helping to ease some symptoms of irritable bowel syndrome (IBS). However, many claimed health benefits, such as treating eczema, lack substantial scientific support.
Lactobacillus acidophilus is a rod-shaped, Gram-positive, homofermentative, anaerobic microbe first isolated from infant feces in the year 1900. The species is commonly found in humans, specifically the gastrointestinal tract and oral cavity as well as some speciality fermented foods such as fermented milk or yogurt, though it is not the most common species for this. The species most readily grows at low pH levels, and has an optimum growth temperature of 37 °C. Certain strains of L. acidophilus show strong probiotic effects, and are commercially used in dairy production. The genome of L. acidophilus has been sequenced.
Lactiplantibacillus plantarum is a widespread member of the genus Lactiplantibacillus and commonly found in many fermented food products as well as anaerobic plant matter. L. plantarum was first isolated from saliva. Based on its ability to temporarily persist in plants, the insect intestine and in the intestinal tract of vertebrate animals, it was designated as a nomadic organism. L. plantarum is Gram positive, bacilli shaped bacterium. L. plantarum cells are rods with rounded ends, straight, generally 0.9–1.2 μm wide and 3–8 μm long, occurring singly, in pairs or in short chains. L. plantarum has one of the largest genomes known among the lactic acid bacteria and is a very flexible and versatile species. It is estimated to grow between pH 3.4 and 8.8. Lactiplantibacillus plantarum can grow in the temperature range 12 °C to 40 °C. The viable counts of the "L. plantarum" stored at refrigerated condition (4 °C) remained high, while a considerable reduction in the counts was observed stored at room temperature.
Heyndrickxia coagulans is a lactic acid–forming bacterial species. This species was transferred to Weizmannia in 2020, then to Heyndrickxia in 2023.
Lacticaseibacillus rhamnosus is a bacterium that originally was considered to be a subspecies of L. casei, but genetic research found it to be a separate species in the L. casei clade, which also includes L. paracasei and L. zeae. It is a short Gram-positive homofermentative facultative anaerobic non-spore-forming rod that often appears in chains. Some strains of L. rhamnosus bacteria are being used as probiotics, and are particularly useful in treating infections of the female urogenital tract, most particularly very difficult to treat cases of bacterial vaginosis. The species Lacticaseibacillus rhamnosus and Limosilactobacillus reuteri are commonly found in the healthy female genito-urinary tract and are helpful to regain control of dysbiotic bacterial overgrowth during an active infection. L. rhamnosus sometimes is used in dairy products such as fermented milk and as non-starter-lactic acid bacterium (NSLAB) in long-ripened cheese. While frequently considered a beneficial organism, L. rhamnosus may not be as beneficial to certain subsets of the population; in rare circumstances, especially those primarily involving weakened immune system or infants, it may cause endocarditis. Despite the rare infections caused by L. rhamnosus, the species is included in the list of bacterial species with qualified presumed safety (QPS) status of the European Food Safety Agency.
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.
Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation, giving them the common name lactic acid bacteria (LAB).
Limosilactobacillus reuteri is a lactic acid bacterium found in a variety of natural environments, including the gastrointestinal tract of humans and other animals. It does not appear to be pathogenic and may have health effects.
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.
Limosilactobacillus fermentum is a Gram-positive species in the heterofermentative genus Limosilactobacillus. It is associated with active dental caries lesions. It is also commonly found in fermenting animal and plant material including sourdough and cocoa fermentation. A few strains are considered probiotic or "friendly" bacteria in animals and at least one strain has been applied to treat urogenital infections in women. Some strains of lactobacilli formerly mistakenly classified as L. fermentum have since been reclassified as Limosilactobacillus reuteri. Commercialized strains of L. fermentum used as probiotics include PCC, ME-3 and CECT5716
Limosilactobacillus mucosae is a rod shaped species of lactic acid bacteria first isolated from pig intestines. It has mucus-binding activity. The species is an obligate anaerobe, catalase-negative, doesn't form spores and is non-motile. Its type strain is S32T, and has been found to be most closely related to Limosilactobacillus reuteri.
Lacticaseibacillus paracasei (commonly abbreviated as Lc. paracasei) is a gram-positive, homofermentative species of lactic acid bacteria that are commonly used in dairy product fermentation and as probiotic cultures. Lc. paracasei is a bacterium that operates by commensalism. It is commonly found in many human habitats such as human intestinal tracts and mouths as well as sewages, silages, and previously mentioned dairy products. The name includes morphology, a rod-shaped bacterium with a width of 2.0 to 4.0μm and length of 0.8 to 1.0μm.
Limosilactobacillus pontis is a rod-shaped, Gram-positive facultatively anaerobic bacterium. Along with other Lactobacillus species, it is capable of converting sugars, such as lactose, into lactic acid. Limosilactobacillus pontis is classified under the phylum Bacillota, class Bacilli, and is a member of the family Lactobacillaceae and is found to be responsible for the fermentation of sourdough, along with many other Lactobacillus species. This microorganism produces lactic acid during the process of fermentation, which gives sourdough bread its characteristic sour taste.
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Limosilactobacillus vaginalis is a lactic acid bacterium that is a normal, but infrequent part of the vaginal microbiome.