title: FISH analysis of Lactobacillus biofilms in the gastrointestinal tract of different hosts.
abstract: OBJECTIVE
  To investigate the spatial organization of endogenous and exogenously applied Lactobacillus communities at specific locations in the adult gastrointestinal tract of different hosts.
  
  
  RESULTS
  Samples of the human, murine and avian gastrointestinal tract of subjects that received or not received a Lactobacillus probiotic were analysed by fluorescence in situ hybridization (FISH) with rRNA-targeted probes. High levels of endogenous lactobacilli were observed on the nonsecretory, stratified squamous epithelia present in the forestomach of mice and crop of chickens, respectively. These epithelial associations showed characteristics of bacterial biofilms, i.e. bacteria attached to a surface and embedded in a matrix of extracellular polymeric substances. In other regions of the analysed intestines, lactobacilli seemed to occur mainly as dispersed bacterial cells or as microcolonies. Exogenous administration of a Lactobacillus probiotic did increase the levels of loosely adherent Lactobacillus cells detected. However, the probiotic strains were unable to establish themselves inside the gastrointestinal biofilms.
  
  
  CONCLUSIONS
  Gastrointestinal biofilms of lactobacilli occur only in specific niches in certain hosts, such as the murine forestomach and avian crop.
  
  
  CONCLUSIONS
  Biofilm formation by lactobacilli in specific parts of animal gastrointestinal tracts was documented for the first time by FISH.
authors.affiliation: Centre of Microbial and Plant Genetics, K.U.Leuven, Leuven, Belgium. sarah.lebeer@biw.kuleuven.be
authors.forename: S
authors.initials: S
authors.lastname: Lebeer
authors.forename: T L A
authors.initials: TL
authors.lastname: Verhoeven
authors.forename: I J J
authors.initials: IJ
authors.lastname: Claes
authors.forename: G
authors.initials: G
authors.lastname: De Hertogh
authors.forename: S
authors.initials: S
authors.lastname: Vermeire
authors.forename: J
authors.initials: J
authors.lastname: Buyse
authors.forename: F
authors.initials: F
authors.lastname: Van Immerseel
authors.forename: J
authors.initials: J
authors.lastname: Vanderleyden
authors.forename: S C J
authors.initials: SC
authors.lastname: De Keersmaecker
mesh_terms: D000818:Animals; D018441:Biofilms; D002645:Chickens; D003426:Crop, Avian / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007422:Intestines / Q000382:microbiology; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019936:Probiotics; D016032:Randomized Controlled Trials as Topic; D013270:Stomach / Q000382:microbiology