There has been rapid progress in the characterization of a large number of probiotic species and their strains from the genus Bifidobacterium in the last two decades. This has given rise to the subsequent interest in the scientific community and commercialization of the strains for their ability as probiotics to render essential health benefits. The members of the bifidobacteria are natural inhabitant of the GI tract in humans and other animals and are gram (+) in nature.
The genus discovered at the beginning of this century has gained significant importance as key component of human-microbial commensal relationships. They are believed to play critical role in the maintenance of the health of the human gastrointestinal tract. Although the importance of the bifidobacteria in maintaining our well being is now being generally accepted but their molecular mode of action in providing the due beneficial effects is far from being delineated.
However, the genome sequencing of some of the key members of the genus is now available and it can just be the starting step in the right direction to understand the bacteria and their probiotic role in the maintenance of human health. A deeper understanding of the strains in this genus and their diversity in tolerating extreme physiological pressure and conditions can allow us to put the specific strain in use in specific cases of health complications.
The History of The Bifidobacterium Genus:
The bifidobacteria were for the first time recognized and isolated by Henry Tissier around 1900. His observations on the microflora in the feces of breast fed infants led to the identification of certain Y-shaped irregular bacteria (bifids) which we now know as the bifidobacteria. Although initially termed as Bacillus bifidus, recognizing their true potential and diversity the Danish microbiologist Jensen proposed for their inclusion under a separate genus Bifidobacterium.
Jensen in the year 1924 went on to further explain the positioning of the bifidobacteria in between the propionic acid and lactic acid bacteria and why they should be in a separate genus. With time the proposal of Jensen was largely accepted by the scientific community. With the passing years, significant modifications took place to resurrect the genus Bifidobacterium. The detailing of the genus took place with studies that involved G/C content, metabolic capacities and DNA hybridization techniques. There are now 30 species listed in the genus Bifidobacterium isolated majorly from the GI tracts possessing the physiology and morphology that characterizes them.
The sequencing of the genome of organisms has put forth a great deal of information in understanding their key features and regulatory mechanisms. With respect to the probiotic strains a knowledge about the sequence of the strains and their comparison can bring about essential data to help reveal the variation in their response to specific conditions and also to provide benefits of specific nature. Currently, two of the B. longum strains have been sequenced and are available in public databases.
The genome of a B. breve has also been in the final stages of sequence assembly. Many important informations like the presence of specific genes required for the specific roles of the bacteria can be gathered from these sequences. A comparison between different sequences from the same genus can shed light on the conserved region of the genome as well as the variation that has been incorporated due to their habitat through generations.
There have been numerous reports of the health benefits provided by the Bifidobacterium strains. Their role have been found to be important to the health of infants, adolescents, youths and aged. There is also no such distinction in the efficiency of their beneficial effects according to the sex of the individuals.
It has already been an established fact that the bifidobacterial population constitutes nearly 95% of the bacterial community in the neonatals who have been breast fed. With increasing age the relative abundance of the bifidobacteria decreases which might explain some of the age related disorders in the elderly population and needs to be replaced with proper probiotic supplements containing the right combination and dosage of the bacterial strains. Nonetheless, the strains of the genus bifidobacteria are associated with the alleviation of a number of human diseased conditions like lactose intolerance, pregnancy complications, constipation, microbial infection, inflammatory bowel disease, diarrhea and so on.
Bifidobacterium in Synergism With Prebiotics:
The prebiotics have been found to be beneficial to human health but not without the help of the beneficial microflora the probiotics. Since, the humans lack the enzymes needed to break down these complex saccharides, they need the help of the microorganisms that possess the requisite enzymes for the metabolism of the complex compounds and release many essential nutrients that can be easily absorbed by the intestines. Also, they produce byproducts that can lead to significant health benefits. The Bifidobacterium members have been found to be quite effective in the break down of the undigestible carbohydrates. Infact some of the prebiotics have been found to be selectively metabolized by the strains of bifidobacterial species that they have even been sometimes termed bifidogenic factors.
Safety in The Use
With all the health benefits provided by the members of the genus Bifidobacterium, the obvious question that arises is how safe are the bifidobacterial strains. The safety of the strains has been established through the consumption of the milk that contained bifidobacteria from ancient times. According to a recent report, the usage of the bifidobacterial strains posed no safety threat to the consumers. Modern day technologies like PCR, 16S rRNA based sequencing have allowed to make distinction between the strains and that have enabled the application of specific strains under specific cases thereby minimizing any side effects that the context dependent intake of the probiotics could have imposed on to the health of the hosts.
It is noteworthy to mention that the safety of the application of the strains is regulated by the European Regulatory Framework. It will recognize the criteria to assess the validity to call a particular strain safe when used in food or even animal feed industry.
The genus Bifidobacterium has been an important component in the origin of the concept of probiotics from time immemorial. It is only just that their true health benefit potentials are recognized and put to use according to the need of the consumer.