title: Filifactor alocis--involvement in periodontal biofilms.
abstract: BACKGROUND
  Bacteria in periodontal pockets develop complex sessile communities that attach to the tooth surface. These highly dynamic microfloral environments challenge both clinicians and researchers alike. The exploration of structural organisation and bacterial interactions within these biofilms is critically important for a thorough understanding of periodontal disease. In recent years, Filifactor alocis, a fastidious, Gram-positive, obligately anaerobic rod was repeatedly identified in periodontal lesions using DNA-based methods. It has been suggested to be a marker for periodontal deterioration. The present study investigated the epidemiology of F. alocis in periodontal pockets and analysed the spatial arrangement and architectural role of the organism in in vivo grown subgingival biofilms.
  
  
  RESULTS
  A species-specific oligonucleotide probe, FIAL, was designed and evaluated. A total of 490 subgingival plaque samples were submitted to PCR and subsequent dot blot hybridization to compare the prevalence of F. alocis in patients suffering from generalized aggressive periodontitis (GAP), chronic periodontitis (CP), and control subjects resistant to periodontitis. Moreover, a specially designed carrier system was used to collect in vivo grown subgingival biofilms from GAP patients. Subsequent topographic analysis was performed using fluorescence in situ hybridization.While the majority of patients suffering from GAP or CP harboured F. alocis, it was rarely detected in the control group. In the examined carrier-borne biofilms the organism predominantly colonized apical parts of the pocket in close proximity to the soft tissues and was involved in numerous structures that constitute characteristic architectural features of subgingival periodontal biofilms.
  
  
  CONCLUSIONS
  F. alocis is likely to make a relevant contribution to the pathogenetic structure of biofilms accounting for periodontal inflammation and can be considered an excellent marker organism for periodontal disease.
authors.affiliation: Institut für Mikrobiologie und Hygiene, Charité - Universitätsmedizin Berlin, Dorotheenstrasse 96, 10117 Berlin, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schlafer
authors.forename: Birgit
authors.initials: B
authors.lastname: Riep
authors.forename: Ann L
authors.initials: AL
authors.lastname: Griffen
authors.forename: Annett
authors.initials: A
authors.lastname: Petrich
authors.forename: Julia
authors.initials: J
authors.lastname: Hübner
authors.forename: Moritz
authors.initials: M
authors.lastname: Berning
authors.forename: Anton
authors.initials: A
authors.lastname: Friedmann
authors.forename: Ulf B
authors.initials: UB
authors.lastname: Göbel
authors.forename: Annette
authors.initials: A
authors.lastname: Moter
mesh_terms: D010520:Aggressive Periodontitis / Q000382:microbiology*; D018441:Biofilms; D016009:Chi-Square Distribution; D005673:Fusobacterium / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D005674:Fusobacterium Infections / Q000382:microbiology*; D006801:Humans; D015151:Immunoblotting; D017404:In Situ Hybridization, Fluorescence; D009693:Nucleic Acid Hybridization; D010514:Periodontal Pocket / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012680:Sensitivity and Specificity; D013048:Specimen Handling