Genomic identification and quantification of microbial species adhering to toothbrush bristles after disinfection: A cross-over study

• We identified and quantified bacterial colonization on toothbrushes.
• We identified and quantified Candida colonization on toothbrushes.
• Total and individual microbial counts were recorded after bristles disinfection.
• Cetylpyridinium chloride reduced total and individual microbial counts.
• Chlorhexidine gluconate reduced total Candida counts.

PurposeThe aim of this clinical investigation was to identify and quantify the microbial species adhering to toothbrush bristles after controlled brushing and storage in different antimicrobial agents.MethodsSixteen healthy participants were enrolled in this study and randomly submitted to 4 interventions in a cross-over design: brushing and toothbrush storage in (I) Periogard/(II) Periobio (Chlorhexidine gluconate 0.12%), (III) Cepacol (cetylpyridinium chloride 0.05%) and (IV) distilled water (positive control). Thirty-eight bacterial species including putative pathogens and 5 Candida spp. were assessed by Checkerboard DNA-DNA hybridization.ResultsThe results of the study have shown a striking reduction of the total microbial counts, including bacteria and Candida spp., on the toothbrush bristles after storage in cetylpyridinium chloride 0.05% (p < 0.0001). Chlorhexidine gluconate 0.12% showed no differences on the total bacterial count when compared to distilled water (p > 0.05). Cetylpyridinium chloride solution also presented the lowest genome counts and frequency of detection for individual target species; distilled water showed the highest individual genome counts (p < 0.05). Potential pathogenic species were recorded in moderate to high levels for chlorhexidine gluconate and distilled water.ConclusionCetylpyridinium chloride 0.05% was the most effective storage solution in the reduction of total and individual microbial counts, including pathogenic species.