title: Bacterial diversity in aphthous ulcers.
abstract: BACKGROUND
  Recurrent aphthous ulcers are common lesions of the oral mucosa of which the etiology is unknown. This study aimed to estimate the bacterial diversity in the lesions and in control mucosa in pooled samples using a culture-independent molecular approach.
  
  
  METHODS
  Samples were collected from ten healthy individuals and ten individuals with a clinical history of recurrent aphthous ulcers. After DNA extraction, the 16S ribosomal RNA bacterial gene was amplified by polymerase chain reaction with universal primers; amplicons were cloned, sequenced and matched to the GenBank database.
  
  
  RESULTS
  A total of 535 clones were analyzed, defining 95 bacterial species. We identified 62 putative novel phylotypes. In recurrent aphthous ulcer lesions 57 phylotypes were detected, of which 11 were known species. Control samples had 38 phylotypes, five of which were already known. Only three species or phylotypes were abundant and common to both groups (Gemella haemolysans, Streptococcus mitis strain 209 and Streptococcus pneumoniae R6). One genus was found only in recurrent aphthous ulcer samples (Prevotella) corresponding to 16% of all lesion-derived clones.
  
  
  CONCLUSIONS
  The microbiota found in recurrent aphthous ulcers and in the control groups diverged markedly and the rich variety of genera found can provide a new starting point for individual qualitative and quantitative analyses of bacteria associated with this oral condition.
authors.affiliation: Laboratory of Molecular Genetics and Genomics, University of Vale do Paraíba, São José dos Campos, São Paulo, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Marchini
authors.forename: M S
authors.initials: MS
authors.lastname: Campos
authors.forename: A M
authors.initials: AM
authors.lastname: Silva
authors.forename: L C
authors.initials: LC
authors.lastname: Paulino
authors.forename: F G
authors.initials: FG
authors.lastname: Nobrega
mesh_terms: D000328:Adult; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D016022:Case-Control Studies; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009061:Mouth Mucosa / Q000382:microbiology; D010802:Phylogeny; D018720:Prevotella / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D017422:Sequence Analysis, DNA; D040141:Staphylococcaceae / Q000302:isolation & purification; D013281:Stomatitis, Aphthous / Q000382:microbiology*; D034361:Streptococcus mitis / Q000302:isolation & purification; D013296:Streptococcus pneumoniae / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S