title: Synergistic effects of antibiotics and an N-acyl homoserine lactone analog on Porphyromonas gingivalis biofilms.
abstract: OBJECTIVE
  To investigate the effects of the combined application of an N-acyl homoserine lactone (HSL) analog and antibiotics on biofilms of Porphyromonas gingivalis, a major pathogen of periodontal disease.
  
  
  RESULTS
  Antibiotics used were cefuroxime, ofloxacin and minocycline. A flow-cell model was used for biofilm formation. Samples were divided into four groups: control, analog-treated, antibiotic-treated and combined application groups. Biofilm cell survival was determined using adenosine triphosphate (ATP) bioluminescence and confocal laser microscopy (CLSM). In the combined application group, the ATP count in biofilm cells was significantly decreased compared with the antibiotic-treated group (Games-Howell test, P < 0·05). A combination of cefuroxime and the analog was most effective against the P. gingivalis biofilm. CLSM observations revealed that the proportion of dead cells was highest in the combined application group.
  
  
  CONCLUSIONS
  The combined application of the N-acyl HSL analog and antibiotics was effective at reducing the viability of P. gingivalis cells in biofilms.
  
  
  CONCLUSIONS
  The combined application of the N-acyl HSL analog and antibiotics may be successful for eradicating infections involving bacterial biofilms, such as periodontitis.
authors.affiliation: Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Asahi
authors.forename: Y
authors.initials: Y
authors.lastname: Noiri
authors.forename: J
authors.initials: J
authors.lastname: Igarashi
authors.forename: H
authors.initials: H
authors.lastname: Suga
authors.forename: H
authors.initials: H
authors.lastname: Azakami
authors.forename: S
authors.initials: S
authors.lastname: Ebisu
mesh_terms: D054742:Acyl-Butyrolactones / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D004357:Drug Synergism; D050296:Microbial Viability / Q000187:drug effects; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010510:Periodontal Diseases / Q000188:drug therapy* / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D054742:Acyl-Butyrolactones; D000900:Anti-Bacterial Agents