Antibacterial activity of povidone–iodine against an artificial biofilm of Porphyromonas gingivalis and Fusobacterium nucleatum

ObjectiveTo investigate the antibacterial activity of povidone–iodine (PVP–I) on an artificial dual species biofilm of periodontal pathogens.DesignPorphyromonas gingivalis or Fusobacterium nucleatum grown in broth culture was inoculated on polycarbonate membrane (PCM) tissue culture inserts. After incubation for 72 h, PVP–I solutions were applied to the biofilm for the time period ranging from 0.5 to 5 min. After addition of a deactivator, each PCM was removed and the biofilm on the PCM was serially diluted and plated on blood agar plates and cultured anaerobically for 7 days. Then viable bacteria were enumerated.ResultsIn the dual species biofilm model, F. nucleatum showed an approximately 200-fold increase in viable counts when compared with mono-microbial biofilm. In dual species biofilm, PVP–I with concentration equal to or greater than 2% was required to significantly reduce P. gingivalis and F. nucleatum. When the contact time of PVP–I was increased to 1 min or greater, no difference in antibacterial activity of PVP–I was observed in any concentration.ConclusionThese results suggest that 30 s application of 2% PVP–I would be effective in suppressing both P. gingivalis and F. nucleatum in dual-species biofilm, and this provides clinical implication for the control of subgingival biofilm.