In vitro inhibition of Helicobacter pylori NCTC 11637 by organic acids and lactic acid bacteria

Abstract

In this study the effects of both pH and organic acids on Helicobacter pylori NCTC 11637 were tested. Lactobacillus acidophilus, Lact. casei, Lact. bulgaricus, Pediococcus pentosaceus and Bifidobacterium bifidus were assayed for their lactic acid production, pH and inhibition of H. pylori growth. A standard antimicrobial plate well diffusion assay was employed to examine inhibitory effects. Lactic, acetic and hydrochloric acids demonstrated inhibition of H. pylori growth in a concentration-dependent manner with the lactic acid demonstrating the greatest inhibition. This inhibition was due both to the pH of the solution and its concentration. Six strains of Lact. acidophilus and one strain of Lact. casei subsp. rhamnosus inhibited H. pylori growth where as Bifidobacterium bifidus, Ped. pentosaceus and Lact. bulgaricus did not. Concentrations of lactic acid produced by these strains ranged from 50 to 156 mmol l-1 and correlated with H. pylori inhibition. The role of probiotic organisms and their metabolic by-products in the eradication of H. pylori in vivo remains to be determined.

In VitroandIn VivoAntibacterial Activities of Patchouli Alcohol, a Naturally Occurring Tricyclic Sesquiterpene, against Helicobacter pylori Infection

“…The results of MIC, MBC, and killing kinetic assays showed the effective anti-H. pylori abilities of PA and indicated the therapeutic effect of PA against clinical antibiotic-resistant strains. For the acid MIC experiment, pH 5.3 was employed, since H. pylori usually lives under mildly acidic conditions between gastric epithelial cells and the gastric mucosa with pH ranging from 5.3 to 6.9 (21,22). A potent antibacterial activity of PA was found even in low-pH environments.…”

Antioxidant activity and fatty acid profile of fermented milk prepared by Pediococcus pentosaceus

“…One of the potential benefits of ingesting probiotics is their antagonistic effect against harmful microorganisms (Midolo et al 1995). There are innumerable articles that list the effects of probiotics in decreasing gastrointestinal disorder, intestinal bowel syndrome, diarrhea, lactose intolerance etc.…”

Screening of probiotic properties of lactic acid bacteria isolated from Kanjika, an ayruvedic lactic acid fermented product: An in-vitro evaluation

“…Several studies have shown that Lactobacillus rhamnosus GG, Lactobacillus reuteri, Lactobacillus casei and Lactococcus lactis can shorten the duration of diarrhea by approximately 1 day (Kaila et al, 1992;Shornikova et al, 1997;Sugita and Togawa, 1994). Lactobacilli have been shown to be antagonistic to Helicobacter pylori which are implicated in chronic gastritis, stomach carcinoma, gastric and duodenal ulcers and in gnotobiotic murine models (Aiba et al, 1998;Kabir et al, 1997;Midolo et al, 1995).…”