Research Article Volume 2 Issue 4 - March 2017 DOI: 10.19080/AIBM.2017.02.555592 Adv Biotech & Micro Copyright © All rights are reserved by Trudy M Wassenaar Survival of Probiotic E. Coli and Ent. Faecalis in the Human Host after Oral Intake: Results from in Vitro and in Vivo Studies Trudy M Wassenaar 1 *, Massimo Marzorati2,3, Claudia Beimfohr 4 , Alexander Siegl 4 and Kurt Zimmermann 5 1 Molecular Microbiology and Genomics Consultants, Germany 2 University of Ghent (LabMET), Belgium 3 ProDigest BVBA, Belgium 4 Vermicon AG, Germany 5 SymbioPharm GmbH, Germany Submission: February 9, 2017; Published: March 15, 2017 *Corresponding author: Trudy M Wassenaar, Molecular Microbiology and Genomics Consultants, Tannenstrasse 7, 55576 Zotzenheim, Germany, Tel: ; Fax: +49-67-1-901803, Email: Introduction According to the definition proposed by the FAO, probiotics are living organisms that, when ingested in sufficient amounts, are beneficial for the host [1]. For probiotic bacteria to produce the desired beneficial effect, they presumably have to colonise the human intestine for a short period at least, although some would argue probiotics don’t have to be alive to be beneficial [2]. Indeed, bacterial lysates are also marketed for presumed beneficial health effects, but their effects are different from those of products based on living bacteria, even when comparing identical strains and species, as the human body treats abiotic bacterial components more likely as food particles than as members of the intestinal microbiota. In vitro studies suggest that peripheral blood mononuclear cells exposed to bacterial components, such as LPS- and CpG-motif containing oligonucleotides or bacterial lysates respond differently compared to exposure to live probiotic bacteria [3]. For viable probiotic bacteria, surviving the passage through the gastro-intestinal tract (GIT) Adv Biotech & Micro 2(4): AIBM.MS.ID.555592 (2017) 001 Abstract The aim of this study was to determine if commercially available strains of probiotic bacteria belonging to the species Ent. faecalis and E. coli were able to survive passage through the human stomach and colonise the gastrointestinal tract (GIT). Survival of bacteria following exposure to gastric pH levels was assessed using a dynamic in vitro model resembling conditions in the stomach as well as the SHIME® model more closely mimicking the upper GIT environment (stomach and small intestine) during fed conditions. Viability of both Ent. faecalis DSM 16431 and E. coli DSM 17257 decreased during acid exposure. However, subsequent exposure to simulated small intestine conditions resulted in no further decrease. A human volunteer took a single dose of probiotic Ent. faecalis, after which live bacteria were determined for 6 days in faeces by means of targeted cultivation and identification of colonies using species- and strain-specific PCR primers. Detection of the strain’s DNA by PCR in stool samples was positive for 4 days. This duration of colonisation was much shorter compared to previously determined human colonisation by E. coli DSM 17257. In conclusion, probiotic E. coli and Ent. faecalis are susceptible to gastric pH, which reduces their viability with several logs. However, sufficient numbers survive to colonise the gut, so that the bacteria are detected in the stool for several days (Ent. faecalis) and multiple weeks (E. coli) following a single dose. Keywords: Probiotics; GIT; Passage; Colonisation; Human gut; Survival Abbreviations: GIT: Gastro-Intestinal Tract; SHIME: Simulation of the Human Intestinal Microbial Ecosystem; Ent: Enterococcus