For Healthcare Professionals:

What is Lactobacillus bulgaricus B-30892 (LBB)?
Genetic characterization from Cornell University’s Laboratory for Molecular Typing, using the RiboPrinter® Microbial Characterization System identified the organism as a unique strain of Lactobacillus bulgaricus. The taxonomic nomenclature recognized by the International Union of Microbiological Societies that applies to the LacPro probiotic is Lactobacillus delbrueckii, ssp. bulgaricus. Further, the strain has been deposited in the Agricultural Research Service Patent Culture Collection and given the NRRL Accession No. B-30892 (LBB), under IDA (4) status (bacterial strains international collection) to allow its availability to the scientific community.

Why is it important to maintain a healthy balance of intestinal microflora?
Bacteria in the intestine fulfill a number of important functions for humans, including breaking down and aiding in the absorption of otherwise undigestible food; stimulating cell growth; repressing the growth of harmful bacteria, training the immune system to respond only to pathogens; and defending against some diseases.

Another important role of helpful intestinal flora is that they prevent pathogens that would harm an individual from colonizing the intestinal tract, an activity termed the "barrier effect". Yeasts and harmful bacterial species such as Clostridium difficile are unable to grow too much due to competition from helpful intestinal flora species. The barrier effect protects individuals from both invading species and species normally present in the intestinal at low numbers, whose growth is usually inhibited by the intestinal flora. Helpful bacteria prevent the growth of pathogenic species by competing for nutrition and attachment sites to the epithelium of the colon. Some intestinal flora also produce bacteriocins, substances which kill harmful microbes. The process of bacterial fermentation also serves to lower the pH in the colon, preventing the proliferation of harmful species of bacteria and facilitating that of helpful species.

How does the intestinal microflora affect immunity?
Intestinal flora have a continuous and dynamic effect on an individual’s intestinal and systemic immune systems. The bacteria are key in promoting the early development of the intestinal mucosal immune system, both in terms of its physical components and function and continue to play a role later in life in its operation. The bacteria stimulate the lymphoid tissue associated with the intestinal mucosa to produce antibodies to pathogens. The immune system recognizes and fights harmful bacteria, but leaves the helpful species alone.

Recent findings have shown that intestinal bacteria play a role in the expression of Toll-like receptors (TLRs) in the intestine, molecules that help the body repair damage due to injury. TLRs cause parts of the immune system to repair injury caused for example by radiation.

Bacteria can influence the phenomenon known as oral tolerance, in which the immune system is less sensitive to an antigen (including those produced by intestinal bacteria) once it has been ingested. This tolerance, mediated in part by the gastrointestinal immune system and in part by the liver, can reduce an overreactive immune response like those found in allergies and auto-immune disease.

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