title: Oral Microbiota Shift after 12-Week Supplementation with Lactobacillus reuteri DSM 17938 and PTA 5289; A Randomized Control Trial.
abstract: BACKGROUND
  Lactobacillus spp. potentially contribute to health by modulating bacterial biofilm formation, but their effects on the overall oral microbiota remain unclear.
  
  
  RESULTS
  Oral microbiota was characterized via 454-pyrosequencing of the 16S rDNA hypervariable region V3-V4 after 12 weeks of daily Lactobacillus reuteri DSM 17938 and PTA 5289 consumption. Forty-four adults were assigned to a test group (n = 22) that received lactobacilli lozenges (108 CFU of each strain/lozenge) or a control group that received placebo (n = 22). Presence of L. reuteri was confirmed by cultivation and species specific PCR. Tooth biofilm samples from 16 adults before, during, and after exposure were analyzed by pyrosequencing. A total of 1,310,292 sequences were quality filtered. After removing single reads, 257 species or phylotypes were identified at 98.5% identity in the Human Oral Microbiome Database. Firmicutes, Bacteroidetes, Fusobacteria, Proteobacteria, and Actinobacteria were the most abundant phyla. Streptococcus was the most common genus and the S. oralis/S. mitis/S. mitis bv2/S. infantis group comprised the dominant species. The number of observed species was unaffected by L. reuteri exposure. However, subjects who had consumed L. reuteri were clustered in a principal coordinates analysis relative to scattering at baseline, and multivariate modeling of pyrosequencing microbiota, and culture and PCR detected L. reuteri separated baseline from 12-week samples in test subjects. L. reuteri intake correlated with increased S. oralis/S. mitis/S. mitis bv2/S. infantis group and Campylobacter concisus, Granulicatella adiacens, Bergeyella sp. HOT322, Neisseria subflava, and SR1 [G-1] sp. HOT874 detection and reduced S. mutans, S. anginosus, N. mucosa, Fusobacterium periodicum, F. nucleatum ss vincentii, and Prevotella maculosa detection. This effect had disappeared 1 month after exposure was terminated.
  
  
  CONCLUSIONS
  L. reuteri consumption did not affect species richness but induced a shift in the oral microbiota composition. The biological relevance of this remains to be elucidated.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT02311218.
authors.affiliation: Department of Odontology/section of Cariology, Umeå University, Umeå, Sweden.
authors.forename: Nelly
authors.initials: N
authors.lastname: Romani Vestman
authors.affiliation: Department of Microbiology, The Forsyth Institute, Cambridge, United States of America.
authors.forename: Tsute
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Odontology/section of Pedodontics, Umeå University, Umeå, Sweden.
authors.forename: Pernilla
authors.initials: P
authors.lastname: Lif Holgerson
authors.affiliation: Department of Odontology/section of Cariology, Umeå University, Umeå, Sweden.
authors.forename: Carina
authors.initials: C
authors.lastname: Öhman
authors.affiliation: Department of Odontology/section of Cariology, Umeå University, Umeå, Sweden.
authors.forename: Ingegerd
authors.initials: I
authors.lastname: Johansson
mesh_terms: D000328:Adult; D018441:Biofilms / Q000254:growth & development; D004269:DNA, Bacterial / Q000235:genetics; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D052200:Limosilactobacillus reuteri / Q000145:classification* / Q000254:growth & development; D008297:Male; D064307:Microbiota / Q000235:genetics*; D008875:Middle Aged; D009055:Mouth / Q000382:microbiology*; D019936:Probiotics / Q000627:therapeutic use*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012463:Saliva / Q000382:microbiology*; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S