title: Survival and synergistic growth of mixed cultures of bifidobacteria and lactobacilli combined with prebiotic oligosaccharides in a gastrointestinal tract simulator.
abstract: BACKGROUND
  Probiotics, especially in combination with non-digestible oligosaccharides, may balance the gut microflora while multistrain preparations may express an improved functionality over single strain cultures. In vitro gastrointestinal models enable to test survival and growth dynamics of mixed strain probiotics in a controlled, replicable manner.
  
  
  METHODS
  The robustness and compatibility of multistrain probiotics composed of bifidobacteria and lactobacilli combined with mixed prebiotics (galacto-, fructo- and xylo-oligosaccharides or galactooligosaccharides and soluble starch) were studied using a dynamic gastrointestinal tract simulator (GITS). The exposure to acid and bile of the upper gastrointestinal tract was followed by dilution with a continuous decrease of the dilution rate (de-celerostat) to simulate the descending nutrient availability of the large intestine. The bacterial numbers and metabolic products were analyzed and the growth parameters determined.
  
  
  RESULTS
  The most acid- and bile-resistant strains were Lactobacillus plantarum F44 and L. paracasei F8. Bifidobacterium breve 46 had the highest specific growth rate and, although sensitive to bile exposure, recovered during the dilution phase in most experiments. B. breve 46, L. plantarum F44, and L. paracasei F8 were selected as the most promising strains for further studies.
  
  
  CONCLUSIONS
  De-celerostat cultivation can be applied to study the mixed bacterial cultures under defined conditions of decreasing nutrient availability to select a compatible set of strains.
authors.affiliation: Department of Food Processing, Tallinn University of Technology, Tallinn, Estonia.
authors.forename: Signe
authors.initials: S
authors.lastname: Adamberg
authors.affiliation: Competence Center of Food and Fermentation Technologies, Tallinn, Estonia.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Sumeri
authors.affiliation: Competence Center of Food and Fermentation Technologies, Tallinn, Estonia.
authors.forename: Riin
authors.initials: R
authors.lastname: Uusna
authors.affiliation: Department of Clinical Microbiology, Labmedicine Skåne, Lund, Sweden.
authors.forename: Padma
authors.initials: P
authors.lastname: Ambalam
authors.affiliation: Department of Clinical Microbiology, Labmedicine Skåne, Lund, Sweden ; Danish Innovation Institute, Copenhagen, Denmark.
authors.forename: Kanthi Kiran
authors.initials: KK
authors.lastname: Kondepudi
authors.affiliation: Department of Food Processing, Tallinn University of Technology, Tallinn, Estonia ; Competence Center of Food and Fermentation Technologies, Tallinn, Estonia.
authors.forename: Kaarel
authors.initials: K
authors.lastname: Adamberg
authors.affiliation: Department of Clinical Microbiology, Labmedicine Skåne, Lund, Sweden.
authors.forename: Torkel
authors.initials: T
authors.lastname: Wadström
authors.affiliation: Department of Clinical Microbiology, Labmedicine Skåne, Lund, Sweden.
authors.forename: Asa
authors.initials: A
authors.lastname: Ljungh
keywords: Bifidobacterium; Lactobacillus; gastrointestinal tract simulator; mixed culture; prebiotic oligosaccharides