Survival of Lactic Acid Bacteria in the Human Stomach and Adhesion to Intestinal Cells

Abstract

The survival of four strains of lactic acid bacteria in human gastric juice, in vivo and in vitro, and in buffered saline, pH 1 to 5, has been investigated. The strains studied include two Lactobacillus acidophilus strains, Lactobacillus bulgaricus, and Streptococcus thermophilus. In addition, the adhesion of these strains to freshly collected human and pig small intestinal cells and to pig large intestinal cells has been studied and the effect of milk on both survival and adhesion tested. As a result of these investigations, an in vitro test system for screening potential cultures for use as human dietary adjuncts can be developed. The ability to survive in gastric juice and to adhere varied significantly for the strains tested; L. acidophilus ADH survived and adhered better than the others while S. thermophilus survived and adhered poorly. For all strains, both survival and adhesion was enhanced by milk. As all strains adhered to some extent to both human and pig intestinal cells, the adhesion mechanism is probably a nonspecific attachment as opposed to other reported specific Lactobacillus adhesion to gastric tissue. From the survival and adhesion data it seems feasible to obtain elevated levels of viable Lactobacillus sp. in human intestine by careful selection of the bacterial strains ingested. Furthermore, the in vitro methods used here should be valuable to screen potential strains. The data presented here can then be correlated with human in vivo studies monitoring the beneficial effect of ingestion of these Lactobacillus.

Studies on probiotics properties of two lactobacillus strains

“…However it maintained an acceptable final cell concentration level. These results are comparable to those reported by Conway (1987). Bile addition effects on the evaluated strains are represented in Figure 2.…”

Inulin and levan synthesis by probiotic Lactobacillus gasseri strains: characterization of three novel fructansucrase enzymes and their fructan products

“…Lactobacillus gasseri, which is speculated to be an autochthonous human intestinal organism (Azcarate-Peril et al, 2008), constitutes a major part of the homofermentative Lactobacillus species occupying the human GI tract (Kullen et al, 2000). L. gasseri is associated with a variety of probiotic functions including reduction of activities of faecal mutagenic enzymes (Pedrosa et al, 1995), adherence to intestinal tissues (Conway et al, 1987;Kirjavainen et al, 1998), stimulation of macrophages (Kirjavainen et al, 1999;Tejada-Simon & Pestka, 1999) and production of bacteriocins (Itoh et al, 1995). The probiotic role of several lactobacilli has been attributed to the synthesis of prebiotic fructose-based polysaccharides (fructans) from sucrose involving fructansucrase or fructosyltransferase (FTF) enzymes (Armuzzi et al, 2001;Korakli et al, 2002;Oda et al, 1983).…”

Adhesion of human Lactobacillus acidophilus strain LB to human enterocyte-like Caco-2 cells

“…Kleeman & Klaenhammer (1 982) screened 27 human Lactobacillus isolates and reported that four L. acidophilus strains, BG2F04, MSOl, MS02 and MS04 adhered specifically, in a calcium-independent manner, to human fetal intestinal epithelial cells. Conway et al (1987) reported the adhesion of strain ADH to human colonic cells. Hood & Zottola (1989) observed that the cells of strain BG2F04 closely associate with the brush border of the human intestinal cell line HITC FHs0074 (ATCC CCL 241).…”