Limosilactobacillus reuteri | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Bacillota |
Class: | Bacilli |
Order: | Lactobacillales |
Family: | Lactobacillaceae |
Genus: | Limosilactobacillus |
Species: | L. reuteri |
Binomial name | |
Limosilactobacillus reuteri Zheng et al., 2020 | |
Synonyms | |
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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.
At the turn of the 20th century, L. reuteri was recorded in scientific classifications of lactic acid bacteria, [1] though at this time it was mistakenly grouped as a member of Lactobacillus fermentum . In the 1960s, further work by microbiologist Gerhard Reuter, for whom the species eventually was named, reclassified the species as L. fermentum biotype II. [2]
Significant differences were found between biotype II and other biotypes of L. fermentum, to the point that in 1980 it was identified as a distinct species and the formal species identity, L. reuteri, was proposed. [3] In April 2020, L. reuteri was reassigned to the genus Limosilactobacillus. [4]
Limosilactobacillus reuteri is found in a variety of natural environments. It has been isolated from many foods, especially meats and dairy products. [2] [5] [6] It appears to be essentially ubiquitous in the animal kingdom, having been found in the gastrointestinal tracts and feces of healthy humans, [7] sheep, chickens, [8] pigs, [9] and rodents. [10] It is the only species to constitute a "major component" of the Lactobacillus species present in the gut of each of the tested host animals, [11] and each host seems to harbor its own specific strain of L. reuteri. [10] [12] It is possible that L. reuteri contributes to the health of its host organism in some manner. [13]
Limosilactobacillus reuteri is present as a dominant member of fermenting organisms in type II sourdoughs; several metabolic traits of L. reuteri, including exopolysaccharide formation and conversion of glutamine to glutamate, improve bread quality. [14]
Limosilactobacillus reuteri is known to produce reuterin, [15] reutericin 6 [16] and reutericyclin. [17] [18]
In the late 1980s, Walter Dobrogosz, Ivan Casas and colleagues discovered that L. reuteri produced a novel broad-spectrum antibiotic substance via the organism's fermentation of glycerol. They named this substance reuterin, after Reuter. [15] Reuterin is a multiple-compound dynamic equilibrium (HPA system, HPA) consisting of 3-hydroxypropionaldehyde, its hydrate, and its dimer. [19] [20] At concentrations above 1.4 M, the HPA dimer was predominant. However, at concentrations relevant for biological systems, HPA hydrate was the most abundant, followed by the aldehyde form. [21]
Reuterin inhibits the growth of some harmful Gram-negative and Gram-positive bacteria, along with yeasts, fungi and protozoa. [22] Researchers found that L. reuteri can secrete sufficient amounts of reuterin to achieve the desired antimicrobial effects. Furthermore, since about four to five times the amount of reuterin is needed to kill "good" gut bacteria (i.e. L. reuteri and other Lactobacillus species) as "bad", this would allow L. reuteri to remove gut invaders without harming other gut microbiota. [13]
Some studies questioned whether reuterin production is essential for L. reuteri's health-promoting activity. The discovery that it produces an antibiotic substance led to a great deal of further research. In early 2008, L. reuteri was confirmed to be capable of producing reuterin in the gastrointestinal tract, improving its ability to inhibit the growth of E. coli . [23]
The gene cluster controlling the biosynthesis of reuterin and cobalamin in the L. reuteri genome is a genomic island acquired from an anomalous source. [24]
Although L. reuteri occurs naturally in humans, it is not found in all individuals. Dietary supplementation can sustain high levels of it in those with deficiencies. Oral intake of L. reuteri has been shown to effectively colonize the intestines of healthy individuals. Colonization begins within days of ingestion, although levels drop months later if intake is stopped. [25] L. reuteri is found in breast milk. [26] Oral intake on the mother's part increases the amount of L. reuteri present in her milk, and the likelihood that it will be transferred to the child. [27]
Manipulation of gut microbiota is a complex process that may cause bacteria-host interactions. [28] Although probiotics in general are considered safe, concerns exist about their use in certain cases. [28] [29] Some people, such as those with compromised immune systems, short bowel syndrome, central venous catheters, heart valve disease, and premature infants, may be at higher risk for adverse events. [30] Rarely, consumption of probiotics may cause bacteremia, fungemia and sepsis, potentially fatal infections, in children with compromised immune systems or who are already critically ill. [31]
One of the better documented effects of L. reuteri is a significant reduction of symptom duration in pediatric diarrheal disease. [32] [33] [34] L. reuteri is effective as a prophylactic for this illness; children fed it while healthy are less likely to fall ill with diarrhea. [35] With regard to prevention of gut infections, comparative research found L. reuteri to be more potent than other probiotics. [36] [37] Animal research found it to reduce motor complexes and thus intestinal motility. [38]
Limosilactobacillus reuteri may be effective treating necrotizing enterocolitis in preterm infants. Meta-analysis of randomized studies suggests that L. reuteri can reduce the incidence of sepsis and shorten the required duration of hospital treatment in this population. [39]
Limosilactobacillus reuteri is an effective treatment against infant colic. [40] [41] [42] Studies suggest that colicky infants treated with L. reuteri experience a reduction in time spent crying compared to those treated with simethicone [43] or placebo. [44] However, colic is still poorly understood, and it is not clear why or how L. reuteri ameliorates its symptoms. One theory holds that affected infants cry because of gastrointestinal discomfort; if this is the case, it is plausible that L. reuteri somehow acts to lessen this discomfort, since its primary residence is inside the gut.
Limosilactobacillus reuteri have a pronounced anti-helicobacter activity and its use as adjuvant therapy of H. pylori in children appears to be very promising, especially in the case of detection of infection with H. pylori with no absolute indication of eradication. [45]
Growing evidence indicates L. reuteri is capable of fighting the gut pathogen Helicobacter pylori , which causes peptic ulcers and is endemic in parts of the developing world. One study showed dietary supplementation of L. reuteri alone reduces, but does not eradicate, H. pylori in the gut. [46] Another study found the addition of L. reuteri to omeprazole therapy dramatically increased (from 0% to 60%) the cure rate of H. pylori-infected patients compared to the drug alone. [47] Yet another study showed that L. reuteri effectively suppressed H. pylori infection and decreased the occurrence of dyspeptic symptoms, although it did not improve the outcome of antibiotic therapy. [48]
Llimosilactobacillus reuteri has the potential to suppress H. Pylori infection and may lead to an improvement of H. Pylori-associated gastrointestinal symptoms, [49] reducing specific symptoms such as diarrhea and frequent abdominal distention. [50] In the future, L. reuteri can become a central part of a strategy to avoid using antibiotics and fighting antibiotic resistance in H. pylori infections [51] and besides fighting antibiotics resistance, L. reuteri may be a great alternative treatment for H. pylori causing fewer side effects than antibiotics. [52]
Limosilactobacillus reuteri may be capable of promoting dental health, as it has been proven to kill Streptococcus mutans , a bacterium responsible for tooth decay. A screen of several probiotic bacteria found L. reuteri was the only tested species able to block S. mutans. Before testing in humans began, another study showed L. reuteri had no harmful effects on teeth. Clinical trials proved that people whose mouths are colonized with L. reuteri (via dietary supplementation) have significantly less S. mutans. [53] Since these studies were short-term, it is not known whether L. reuteri prevents tooth decay. However, since it is able to reduce the numbers of an important decay-causing bacterium, this would be expected.
Gingivitis may be ameliorated by consumption of L. reuteri. Patients afflicted with severe gingivitis showed decreased gum bleeding, plaque formation and other gingivitis-associated symptoms compared with placebo after chewing gum containing L. reuteri. [54]
Lactobacillus reuteri and other probiotics may influence the gut microbiome in ways that protect against bone loss, common in post-menopausal women. [55] [56] [57] [58] [59]
By protecting against many common infections, L. reuteri promotes overall wellness in both children and adults. Double-blind, randomized studies in child care centers have found L. reuteri-fed infants fall sick less often, require fewer doctor visits and are absent fewer days from the center compared to placebo and to the competing probiotic Bifidobacterium lactis . [60]
Similar results have been found in adults; those consuming L. reuteri daily end up falling ill 50% less often, as measured by their decrease use of sick leave. [61]
Scientific studies that require harming the subjects (for example, exposing them to a dangerous virus) cannot be conducted in humans. Therefore, many of L. reuteri's benefits have been studied only in different animal species, such as pigs and mice.
In general, animal studies on L. reuteri are done using the species-specific strain of the bacterium.
Limosilactobacillus reuteri confers a high level of resistance to the pathogen Salmonella typhimurium , halving mortality rates in mice. [62] The same is true for chickens [63] and turkeys; L. reuteri greatly moderates the morbidity and mortality caused by this dangerous food-borne pathogen.
Limosilactobacillus reuteri is effective in stopping harmful strains of E. coli from affecting their hosts. A study performed in chickens showed L. reuteri was as potent as the antibiotic gentamicin in preventing E. coli-related deaths. [64]
The protozoic parasite Cryptosporidium parvum causes severe watery diarrhea, which can become life-threatening in immunocompromised (as in individuals infected with HIV) patients. L. reuteri is known to lessen the symptoms of C. parvum infection in mice [65] and pigs. [13]
Some protective effect against the yeast Candida albicans has been found in mice, but in this case, L. reuteri did not work as well as other probiotic organisms, such as L. acidophilus and L. casei . [66]
In juvenile commercial livestock, such as turkey poults and piglets, body weight and growth rate are good health indicators. Animals raised in the dirty, crowded environments of commercial farms are generally less healthy (and therefore weigh less) than their counterparts born and bred in cleaner spaces. In turkeys, for example, this phenomenon is known as "poult growth depression", or PGD. [67]
Supplementing the diets of these young animals with L. reuteri helps them to largely overcome the stresses imposed by unhealthy environs. Commercial turkeys fed L. reuteri from birth had nearly a 10% higher adult body weight than their peers raised in the same conditions. [68] A similar study on piglets showed L. reuteri is at least as effective as synthetic antibiotics in improving body weight under crowded conditions. [69]
The mechanism by which L. reuteri is able to support healthy growth is not entirely understood. It possibly serves to protect against illness caused by S. typhimurium and other pathogens (see above), which are much more common in crowded commercial farms. However, other studies found that it can help when the growth depression is caused entirely by a lack of dietary protein, and not by contagious disease. [70] This raises the possibility that L. reuteri somehow improves the intestines' ability to absorb and process nutrients. [13]
Treating colonic tissue from rats with acetic acid causes an injury similar to the human condition ulcerative colitis. Treating the injured tissue with L. reuteri immediately after removing the acid almost completely reverses any ill effects, [71] leading to the possibility that L. reuteri may be beneficial in the treatment of human colitis patients.
In addition to its role in digestion, the intestinal wall is also vital in preventing harmful bacteria, endotoxins, [72] etc., from "leaking" into the bloodstream. This leaking, known as bacterial "translocation", can lead to lethal conditions such as sepsis. In humans, translocation is more likely to occur following such events as liver injury and ingestion of some poisons. In rodent studies, L. reuteri was found to greatly reduce the amount of bacterial translocation following either the surgical removal of the liver [73] or injection with D-galactosamine, [74] a chemical which causes liver damage.
The anticancer drug methotrexate causes severe enterocolitis in high doses. L. reuteri greatly mitigates the symptoms of methotrexate-induced enterocolitis in rats, one of which is bacterial translocation. [75]
In mice, the absence of L. reuteri has been causally linked to maternal diet. [72] A gut microbial imbalance, lacking in L. reuteri, was linked to behavioral abnormalities consistent with autism in humans. [72] These symptoms were reversible by supplementing L. reuteri. [72]
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.
Helicobacter pylori, previously known as Campylobacter pylori, is a gram-negative, flagellated, helical bacterium. Mutants can have a rod or curved rod shape, and these are less effective. Its helical body is thought to have evolved in order to penetrate the mucous lining of the stomach, helped by its flagella, and thereby establish infection. The bacterium was first identified as the causal agent of gastric ulcers in 1983 by the Australian doctors Barry Marshall and Robin Warren.
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, but there is little evidence for many of the health benefits claimed for them.
Lacticaseibacillus casei is an organism that belongs to the largest genus in the family Lactobacillaceae, a lactic acid bacteria (LAB), that was previously classified as Lactobacillus casei. This bacteria has been identified as facultatively anaerobic or microaerophilic, acid-tolerant, non-spore-forming bacteria.
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.
Walter Dobrogosz is a professor emeritus of North Carolina State University, best known for his discovery and further research on the probiotic bacterium Lactobacillus reuteri.
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.
Saccharomyces boulardii is a tropical yeast first isolated from lychee and mangosteen fruit peel in 1923 by French scientist Henri Boulard. Although early reports claimed distinct taxonomic, metabolic, and genetic properties, S. boulardii is genetically a grouping of S. cerevisiae strains, sharing >99% genomic relatedness, giving the synonym S. cerevisiae var. boulardii.
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
Helicobacter pylori eradication protocols is a standard name for all treatment protocols for peptic ulcers and gastritis in the presence of Helicobacter pylori infection. The primary goal of the treatment is not only temporary relief of symptoms but also total elimination of H. pylori infection. Patients with active duodenal or gastric ulcers and those with a prior ulcer history should be tested for H. pylori. Appropriate therapy should be given for eradication. Patients with MALT lymphoma should also be tested and treated for H. pylori since eradication of this infection can induce remission in many patients when the tumor is limited to the stomach. Several consensus conferences, including the Maastricht Consensus Report, recommend testing and treating several other groups of patients but there is limited evidence of benefit. This includes patients diagnosed with gastric adenocarcinoma, patients found to have atrophic gastritis or intestinal metaplasia, as well as first-degree relatives of patients with gastric adenocarcinoma since the relatives themselves are at increased risk of gastric cancer partly due to the intrafamilial transmission of H. pylori. To date, it remains controversial whether to test and treat all patients with functional dyspepsia, gastroesophageal reflux disease, or other non-GI disorders as well as asymptomatic individuals.
Probiotics are live microorganisms promoted with claims that they provide health benefits when consumed, generally by improving or restoring the gut flora. Probiotics are considered generally safe to consume, but may cause bacteria-host interactions and unwanted side effects in rare cases. There is little evidence that probiotics bring the health benefits claimed for them.
Reuterin (3-hydroxypropionaldehyde) is the organic compound with the formula HOCH2CH2CHO. It is a bifunctional molecule, containing both a hydroxy and aldehyde functional groups.
BioGaia is a Swedish biotechnology company that develops, markets and sells a range of probiotic products. It has patented the use of several Lactobacillus reuteri strains and offers gut and immune health products containing L. reuteri Protectis, one of the human L. reuteri strain and oral health products containing L. reuteri Prodentis, a blend of the L. reuteri strains DSM 17938 and ATCC PTA 5289. Products containing L. reuteri have been proven to be both effective and safe in several applications: infant colic, diarrhea prevention and mitigation in children, eradication of H. pylori infection and reduction of side effects from standard H. pylori treatment, amelioration of gingivitis, and general illness prevention in children and adults. BioGaia was ranked 9th in the Top 30 Global Probiotic Food Ingredient Companies list by FoodTalks in 2021. The BioGaia -B share is listed on the NASDAQ OMX Nordic Exchange.
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.
Lactobacillus delbrueckii subsp. bulgaricus is a bacterial subspecies traditionally isolated from European yogurts. Lactobacillus bulgaricusGLB44 differs from other L. bulgaricus strains because it was isolated from the leaves of Galanthus nivalis in Bulgaria.
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Postbiotics - also known as metabiotics, biogenics, or simply metabolites - are soluble factors, secreted by live bacteria, or released after bacterial lysis providing physiological benefits to the host.
Limosilactobacillus is a thermophilic and heterofermentative genus of lactic acid bacteria created in 2020 by splitting from Lactobacillus. The name is derived from the Latin limosus "slimy", referring to the property of most strains in the genus to produce exopolysaccharides from sucrose. The genus currently includes 31 species or subspecies, most of these were isolated from the intestinal tract of humans or animals. Limosilactobacillus reuteri has been used as a model organism to evaluate the host-adaptation of lactobacilli to the human and animal intestine and for the recruitment of intestinal lactobacilli for food fermentations.