Bifidobacterium reuteriRANK: Species
TAXONOMY: Terrabacteria group -> Actinobacteria -> Actinobacteria -> Bifidobacteriales -> Bifidobacteriaceae -> Bifidobacterium -> Bifidobacterium reuteri
Lactobacillus reuteri is a Gram-positive bacterium that naturally inhabits the gut of mammals and birds. First described in the early 1980s, some strains of L. reuteri are used as probiotics. BioGaia AB in Sweden owns several commercially important strains and a large number of different patents for commercial usage of L. reuteri. L. reuteri is known to produce antimicrobials reuterin, reutericin 6, and reutericyclin.Although L. reuteri occurs naturally in humans, it is not found in all individuals. Therefore, dietary supplementation is needed to introduce and maintain high levels of it in some people. Oral intake of L. reuteri has been shown to effectively colonize the intestine of healthy people; colonization begins rapidly within days of ingestion, although the levels in the body drop within several months after intake is stopped. Furthermore, L. reuteri is found inbreast milk, and oral intake on the mother's part likewise increases the amount of L. reuteri present in her milk, and the likelihood that it will be transferred to the child's body.Once present in the body, L. reuteri benefits its host in a variety of ways, particularly by fighting off harmful infections and mediating the body's immune system.One of the most well-documented effects of L. reuteri is in the treatment of rotavirus-induced diarrhea, especially in children. Treatment of rotaviral diarrhea by consumption of L. reuteri significantly shortens the duration of the illness as compared to placebo. Furthermore, this effect is dose-dependent: the more L. reuteri consumed, the faster the diarrhea stops. L. reuteri is also effective as a prophylactic for this illness; children fed it while healthy are less likely to fall ill with diarrhea in the first place. With regard to prevention of gut infections, comparative research has found L. reuteri to be more potent than other probiotic organisms. It has also been found in animal research to reduce motor complexes and thus intestinal motility.L. reuteri is also an effective treatment against infant colic. Over a period of several weeks, infants who are given L. reuteri steadily decrease the amount of time each day spent crying – the defining symptom of colic. In fact, it was much better in decreasing the infants' crying time than the standard therapy of simethicone treatment. A randomized, double-blind, placebo-controlled trial of 50 exclusively breast-fed, colicky infants found a significant decrease in daily crying time amounts when treated with L. reuteri DSM 17 938 compared with placebo. It further found a significant increase in lactobacilli colonization, a decrease in fecal Escherichia coli and ammonia when compared with placebo. However, colic is still poorly understood, and it is not clear why or how L. reuteri ameliorates its symptoms. One theory of colic, though, holds that affected infants cry because of severe gastrointestinal discomfort; if this is indeed the case, it is quite plausible that L. reuteri somehow acts to lessen this discomfort, since its primary residence is inside the gut.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 fully eradicate, H. pylori in the gut. 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. Yet another study showed L. reuteri effectively suppressed H. pylori infection and decreased the occurrence of dyspeptic symptoms, although it did not improve the outcome of antibiotic therapy.