Probiotic lactic acid bacteria in the gastro-intestinal tract: health benefits, safety and mode of action

Abstract

Lactic acid bacteria (LAB) have received considerable attention as probiotics over the past few years. This concept has grown from traditional dairy products to a profitable market of probiotic health supplements and functional foods. Extensive research is done on novel potential probiotic strains, with specific emphasis on their health benefits and mode of action. Criteria for the selection of probiotic strains have only recently been formulated by the Food and Agriculture Organization of the United Nations and the World Health Organization (FAO/WHO). Several in vitro techniques have been developed to evaluate the probiotic properties of strains. In many cases, this is followed by in vivo tests. Safety studies are also obligatory, as a few cases of bacteremia caused by LAB have been reported. This review focuses on the health benefits and safety of LAB probiotics, the criteria used to select a probiotic, mode of action and the impact these organisms have on natural microbiota in the gastro-intestinal tract.

Functional Characterization of a Mucus-Specific LPXTG Surface Adhesin from Probiotic Lactobacillus rhamnosus GG

“…In addition, there are those strains, called allochthonous, that persist only briefly in the intestine, many of these being probiotics (1,9,13) and understood to stimulate health-benefiting immune responses in host intestinal cells (for a review, see reference 14) or cause competitive displacement of invading pathogens (for a review, see reference 35). Thus far, the precise molecular mechanisms that differentiate the colonization ability between autochthonous and allochthonous intestinal lactobacilli remain undefined (42), although they are likely to be partly dependent on a diverse range of cell surface adhesion molecule-mediated interactions with the host intestinal mucosa.…”

Bioengineered probiotics, a strategic approach to control enteric infections

“…These include lactose metabolism, improved digestion, increased nutritional value, production of antimicrobial factors, antimycotic effects, anti-carcinogenic properties, immunologic enhancement, production of short-chain fatty acids, antiatherogenic, and cholesterol-lowering attributes, regulatory role in allergy, protection against vaginal or urinary tract infections, maintenance of epithelial integrity and barrier, stimulation of repair mechanism in cells, and maintenance and reestablishment of a well-balanced indigenous intestinal, respiratory, and urogenital microbial communities. 10,[21][22][23][24] 43 A bacteriocin (Microcin S) producing probiotic Escherichia coli G3/10 also suppressed EPEC adherence and pathogenesis. 44 …”

Reporter systems forin vivotracking of lactic acid bacteria in animal model studies

“…It is thus not surprising that the probiotic market is dominated by a few well-studied species of the genera Lactobacillus and Bifidobacterium. 2 It is only in recent years that reports have been published on the probiotic properties of LAB from genera such as Streptococcus, Leuconostoc, Lactococcus and Enterococcus. [3][4][5] Enterococci are usually not included in probiotic preparations, due to their association with abnormal physiological conditions, underlying disease and immunosuppression.…”

“…the alleviation of constipation, treatment and prevention of atopic dermatitis, treatment of irritable bowel syndrome (IBS), prevention of cardiovascular diseases and, more recently, the treatment of cancerous tumors. 1,2 The chance of finding a single strain that adheres to all of these properties is remote, hence the reason for so many strain combinations in probiotic preparations. Many of the strains are selected based on in vitro-attained phenotypic properties that adhere to the general definition of a probiotic and to a lesser extent the ability of cells to colonize the gastro-intestinal tract (GIT).…”