Survival of the probiotic, L-plantarum 299v and its effects on the faecal bacterial flora, with and without gastric acid inhibition

Introduction. Probiotic bacteria have to survive passage through the gastrointestinal tract. In this placebo-controlled double-blind study, the effect of Lactobacillus plantarum 299v on the faecal flora was studied with and without gastric acid inhibition. Methods. Thirty-two healthy volunteers were given pantoprazole (40mg/day) or placebo for 3 weeks from week 2 until week 4. In addition, from week 3 until week 4, L. plantarum 299v in an oatmeal-fermented drink (10(9)CFU/ml) was given twice daily to both groups. From each healthy volunteer, faecal samples were collected at the end of week 1, 2, 4 and 8 (4 weeks after cessation of L. plantarum 299v and pantoprazole/placebo). Several aerobically and anaerobically growing bacteria were counted and short chain fatty acid concentrations were determined. Results. In both the pantoprazole and the placebo group, median lactobacilli counts increased significantly in week 4 compared to week I (from log 4.5 to 8.0 CFU/g faeces in pantoprazole and from log 4.2 to 7.7 CFU/g facces in placebo group) and decreased significantly in week 8 (to log 4.5 CFU/g faeces in pantoprazole and log 4.3 CFU/g faeces in placebo group). These lactobacilli were identified as L. plantarum 299v. No significant differences were observed in all other bacterial counts and short chain fatty acid concentrations. Conclusions. The comparable increase of faecal lactobacilli counts in both the pantoprazole and the placebo-treated group demonstrates that L. plantarum 299v survives passage through the gastrointestinal tract irrespective of gastric acidity. The increment of the intra-gastric pH in combination with L. plantarum 299v did not modulate bacterial composition and/or the production of short chain fatty acids. (C) 2004 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.