''Bifidobacterium bifidum'' is a bacterial species of the genus '' Bifidobacterium''. ''B. bifidum'' is one of the most common

probiotic Probiotics are live microorganisms that provide health benefits when consumed, generally by improving or restoring the microbiota in the gut. Probiotics are considered generally safe to consume, but may cause bacteria– host interactions ...

bacteria that can be found in the body of

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s, including humans.

Structure and characteristics

''B. bifidum'' is a

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

, anaerobic bacterium that is neither motile nor spore-forming. The bacterium is rod-shaped and can be found living in clusters, pairs, or even independently. The majority of the population of ''B. bifidum'' is found in the colon, lower small intestine, breast milk, and often in the

vagina In mammals and other animals, the vagina (: vaginas or vaginae) is the elastic, muscular sex organ, reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The #Vag ...

. ''B. bifidum'' (along with ''B. longum'' and ''B. breve'') dominates in breastfed infants. With age, this composition alters in favor of other bifidobacteria species, and the total bifidobacteria population declines to lower but relatively stable levels. ''B. bifidum'' is an essential bacteria found in the human intestine. When it is low or absent all together in the human intestine, it is an indication of being in an unhealthy state. Intestinal flora can be improved if someone takes oral ''B. bifidum''. Also, oral ''B. bifidum'' is used for other things such as therapy for enteric and hepatic disorders, for activating the immune response, and for preventing some cancers.

Benefits

Various strains of ''B. bifidum'' have been shown to confer significant health benefits to their human host. * Antibacterial activity: ''B. bifidum'' BF-1 and CECT 7366 exhibit activity against pathogens, including ''Helicobacter pylori''. * Gut health improvement: ''B. bifidum'' MIMBb75 and DSM 20082 help alleviate symptoms of irritable bowel syndrome (IBS) and certain chronic large bowel dysfunctions. * Reduction of apoptosis: ''B. bifidum'' OLB6378 reduces apoptosis in the intestinal epithelium of infants with necrotizing enterocolitis. * Immune modulation: ATCC 86321 and S17 influence immune responses by balancing inflammatory and anti-inflammatory activity. Additionally, ''B. bifidum'' demonstrates strong adhesion to intestinal epithelial cells, a critical feature for its persistence in the gastrointestinal tract and its ability to provide health-promoting effects. This species also plays an essential role in establishing a balanced intestinal microbiota in newborns, working alongside '' B. breve'' and ''B. longum'' subsp. ''infantis''.

Health concerns

The manipulation of the

gut flora Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

is complex and may cause bacteria-host interactions. Although

s, in general, are considered safe, there are concerns about their use in certain cases. Some people, such as those with compromised immune systems,

short bowel syndrome Short bowel syndrome (SBS, or simply short gut) is a rare malabsorption disorder caused by a lack of functional small intestine. The primary symptom is diarrhea, which can result in dehydration, malnutrition, and weight loss. Other symptoms may i ...

, central venous catheters, heart valve disease and premature infants, may be at higher risk for adverse events. Rarely, consumption of probiotics may cause

bacteremia Bloodstream infections (BSIs) are infections of blood caused by blood-borne pathogens. The detection of microbes in the blood (most commonly accomplished by blood cultures) is always abnormal. A bloodstream infection is different from sepsis, wh ...

, and

sepsis Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...

, potentially fatal infections in children with lowered immune systems or who are already critically ill.

Maternal inheritance and persistence in gut microbiota

''B. bifidum'' is among the first microbial colonizers of the infant gut, introduced through maternal transmission during birth and breastfeeding. This vertical transmission process facilitates the establishment of ''B. bifidum'' and other bifidobacteria, which are commonly found in both the mother's gut and milk. Studies using metagenomics and profiling techniques have identified specific strains of ''B. bifidum'' shared between mothers and infants, persisting in the infant gut for up to a year. Such maternal inheritance highlights the evolutionary relationship between bifidobacteria and their hosts, with maternal milk serving as a critical vector for colonization. This process can be disrupted under non-natural conditions like cesarean delivery or formula feeding. Beyond early life, ''B. bifidum'' exhibits persistence in the human gut, albeit at lower abundances, throughout life. Its ability to persist is attributed to unique genomic features, including genes for extracellular structures like exopolysaccharides, pili, and enzymes involved in carbohydrate metabolism. These features enable ''B. bifidum'' to utilize complex dietary carbohydrates and host-derived glycans, such as mucin and human milk oligosaccharides (HMOs), providing a competitive advantage for colonization and resilience in the gut environment. Strains capable of metabolizing HMOs and mucin demonstrate higher resilience and are better equipped for long-term colonization, making ''B. bifidum'' a crucial contributor to gut health and microbial stability across life stages. Research suggests that the surface protein transaldolase (TAL) allows ''B. bifidum'' to bind to mucins

MUC1 Mucin short variant S1, also called polymorphic epithelial mucin (PEM) or epithelial membrane antigen (EMA), is a mucin encoded by the ''MUC1'' gene in humans. Mucin short variant S1 is a glycoprotein with extensive O-linked glycosylation of its ...

and MUC2, allowing metabolism of mucins as well as aiding in binding and colonization of the intestinal epithelium where ''B. bifidum'' can have contribute to gut health.

Research on different Bifidobacterium strains

MIMBb75

''B. bifidum'' MIMBb75 is a probiotic strain isolated from a healthy adult. It is recognized for its strong adhesion to intestinal cells and its role in immune system modulation. The strain has demonstrated effectiveness in reducing symptoms of

irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by a group of symptoms that commonly include abdominal pain, abdominal bloating, and changes in the consistency of bowel movements. These symptoms may ...

(IBS) and is available as a pharmaceutical probiotic product in encapsulated form.

BGN4

''B. bifidum'' BGN4 has been used in health products and dairy production since 2000. It offers multiple health benefits, including supporting immune health, reducing IBS symptoms, and aiding in eczema treatment. Research has also suggested anti-cancer properties and interactions with plant-based compounds. Recent genomic studies highlight its potential for broader applications.

PRL2010

''B. bifidum'' PRL2010 is noted for its immune-boosting effects, helping balance inflammation and promoting gut health. It can metabolize complex sugars in the gut, facilitating its colonization of the intestine. This strain also produces pili, which enhance its ability to adhere to intestinal surfaces and inhibit the adhesion of pathogens such as '' E. coli''.

E3

''B. bifidum'' E3 in combination with ''B. longum subsp. infantis'' E4 has shown probiotic effect, aiding in reducing intestinal inflammation and improving gut microbiota in mice. Inflammation was reduced via suppression of NFκB/MAPK pathways and lower levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α). ''In vitro'' research into recombinant TAL protein of ''B. bifidum'' E3 suggests that this protein is able to inhibit this NF-κB pathway by preventing p65 nuclear translocation while upregulating

PI3K Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which i ...

and AKT signaling pathways. TAL therefore suppresses pro-proinflammatory cytokine IL-8, while also upregulating anti-inflammatory cytokine IL-10.

References

External links

Type strain of ''Bifidobacterium bifidum'' at Bac''Dive'' – the Bacterial Diversity Metadatabase
{{Authority control Bifidobacteriales Probiotics Bacteria described in 1900