Bifidobacteria Case Study

Initially Tissier (1899) used bifidobacteria for treatment of diarrhea in infants by giving bifidobacteria orally. Since then much of the research has been carried out to reveal the mode of action of these bacteria in the intestine. He reviewed bifidobacteria by analyzing characteristics, ecology and role in human systems. He proposed that bifidobacteria are involved in the production of antimicrobial substances and also compete for nutrients with pathogens. In addition, they also contend for adhesion receptors and take part in the stimulation of immunity, thus acting as probiotics.

Lilly and Stillwell (1965) first used the term ‘probiotics’ in a different context to represent that substances secreted by one organism which stimulate the growth

These bacteria found from fermented dairy products are subject to their survival during production and storage. The use of probiotic bacteria is increasing in food and pharmaceutical applications. The disturbed intestinal microflora and other dysfunction of the human G.I tract can be balanced by probiotics use. Lactobacillus acidophilus and Bifidobacterium spp. have found to be beneficial probiotic organisms that provide outstanding therapeutic benefits. This biological activity of probiotic bacteria is due to their ability to attach to enterocytes. By a process of competitive exclusion, they inhibit the binding of enteric pathogens. The inclusion of probiotic bacteria in fermented dairy products improves their value as better supplement foods. However, inadequate sustainability and survival of these bacteria is a problem. By selecting useful probiotic strains and enhancing their survival, appropriate probiotics combining with prebiotics (synbiotics) can be useful in future for the consumer market. According to Sultana et al. (2000) breast-fed infants harbored high numbers of bifidobacteria, resisting intestinal infections better than formula-fed that’s why bifidobacteria have been incorporated into probiotic foods. Health benefits of bifidobacteria to the host had led to their wide application as probiotic components

(2004) compared the ability of bifidobacteria isolated from infant feces to inhibit enterohemorrhagic Escherichia coli serotype O157:H7 in-vitro to bifidobacterial reference strains collected from American Type Culture Collection (ATCC). Bifidobacteria reduced its adhesion to human enterocyte-like Caco-2 cells. He used the carbohydrate fermentation patterns to carry out agar spot technique, resistance to lysozyme, acid, bile and hydrogen peroxide as well as their ability to inhibit E. coli O157:H7. Five Bifidobacterium isolates were identified and characterized on the bases of morphology, fructose-6-phosphate phosphoketolase (F6PPK) assay, and polymerase chain reaction by using bifidobacterial 16S rDNA specific primers. Infant isolates showed greater resistance to acid, bile, and lysozyme and had greater antimicrobial activity against E. coli O157:H7 than those of ATCC strains. Two isolates from infants identified as B. bifidum RBL 71 and B. bifidum RBL 460 were well adhered to Caco-2 cells and significantly reduced potential of attachment of E. coli O157:H7 with Caco-2 cells. This effect was dependent on bifidobacterial cell concentration. These results confirmed that the infant bifidobacterial isolates significantly improved probiotic formulae by protecting against E. coli O157:H7