title: The effect of a multi-strain probiotic on the resistance toward Escherichia coli challenge in a randomized, placebo-controlled, double-blind intervention study.
abstract: BACKGROUND
  Several probiotic strains have been shown to enhance human resistance to infectious disease. It is speculated that these strains may impose this effect by excretion of anti-microbial components, by competing with pathogens for intestinal nutrients and/or mucosal adhesion sites or modulating the immune system.
  
  
  OBJECTIVE
  A parallel, double-blind, placebo-controlled 4-week intervention was performed in healthy males, to study the effect of a blend of probiotic bacteria (Lactobacillus helveticus Rosell-52, Lactobacillus rhamnosus Rosell-11, Bifidobacterium longum ssp. longum Rosell-175) and a probiotic yeast (Saccharomyces cerevisiae var boulardii CNCM I-1079) on enterotoxigenic Escherichia coli (ETEC) challenge. Primary outcomes studied were fecal ETEC excretion and total fecal output per day.
  
  
  METHODS
  Subjects were randomized to the probiotic (5 × 10(9) colony-forming units (CFUs); twice daily; n=30) or placebo group (twice daily; n=30). After 2 weeks, subjects were orally challenged with a live attenuated ETEC (3 × 10(9) CFU), previously demonstrated to induce mild, short-lived symptoms of a foodborne infection. Before and after ETEC challenge, subjects collected 24 h fecal samples. Compliance to study guidelines, stool consistency (Bristol Stool Score), stool frequency, and frequency and severity of gastrointestinal (GI) complaints were recorded by the subjects on a Daily Record Questionnaire.
  
  
  RESULTS
  ETEC challenge induced a significant increase in fecal ETEC excretion in both groups. However, a statistically significant increase in fecal output was only observed in the probiotic group. ETEC challenge resulted in a decrease in the percentage of fecal dry weight, and an increase in reported Bristol Stool Score, stool frequency and GI complaints. Dietary probiotics significantly decreased the percentage of fecal dry weight. In addition, ETEC increased C-reactive protein, total secretory Immunoglobulin A (IgA) and Immunoglobulin G Colonization Factor Antigen II.
  
  
  CONCLUSIONS
  Dietary probiotics did not increase resistance to oral attenuated ETEC challenge in human subjects.
authors.affiliation: Department of Nutrition and Health, NIZO Food Research, Ede, The Netherlands.
authors.forename: S J M
authors.initials: SJ
authors.lastname: Ten Bruggencate
authors.affiliation: Lallemand Health Solutions, Montreal, Quebec, Canada.
authors.forename: S A
authors.initials: SA
authors.lastname: Girard
authors.affiliation: Department of Nutrition and Health, NIZO Food Research, Ede, The Netherlands.
authors.forename: E G M
authors.initials: EG
authors.lastname: Floris-Vollenbroek
authors.affiliation: Consultant for Lallemand Health Solutions, Montreal, Quebec, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Bhardwaj
authors.affiliation: Lallemand Health Solutions, Montreal, Quebec, Canada.
authors.forename: T A
authors.initials: TA
authors.lastname: Tompkins
mesh_terms: D000328:Adult; D001644:Bifidobacterium; D003672:Defecation; D003967:Diarrhea / Q000382:microbiology* / Q000517:prevention & control; D004311:Double-Blind Method; D004926:Escherichia coli; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control; D005243:Feces / Q000382:microbiology; D006801:Humans; D007422:Intestines / Q000382:microbiology; D007778:Lactobacillus; D007779:Lactobacillus acidophilus; D052198:Lactobacillus helveticus; D052201:Lacticaseibacillus rhamnosus; D008297:Male; D019936:Probiotics / Q000627:therapeutic use; D055815:Young Adult