Quantitative Assessment of Microbial Contamination and Patterns of Public Behaviour with Used Toothbrushes: Implications of Storage and Replacement

Amreen Bashir*, Peter Lambert

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Introduction: Toothbrushes can readily become contaminated with microbes during use and storage. They present a potential hazard of cross-contamination and subsequent infection.
Aims: To investigate the nature and level of microbial contamination of used toothbrushes and influence of participant lifestyle.
Methods and Results: 103 used toothbrushes were donated, and microbial contents were determined by microbial culture and identification. 97% of toothbrushes revealed contamination. The microbial loads ranged from 0-1010 cfu/brush with median values of around 107, with Candida isolated in the highest levels. 90% of toothbrushes were stored in bathrooms presumably exposed to environmental contamination and 72% revealed the presence of enteric bacteria including Klebsiella, Serratia and Enterobacter. 50% of participants kept toothbrushes for >3 months and 40% retained toothbrushes for 4-6 months; microbial loads were fully established during the first three months of use and did not increase further with prolonged use. Only 57% of participants brushed their teeth twice a day and 41% brushed once a day.
Conclusion: Used toothbrushes are heavily contaminated and the presence of potentially pathogenic microorganisms constitutes a potential health risk.
Significance and Impact of Study: There is an under-recognised risk of cross-contamination/infection, especially when multiple users store toothbrushes in close contact. Guidance on toothbrush age, brushing frequency and storage is not being followed. Further education is required to improve public awareness. 
Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalDental Oral Biology and Craniofacial Research
Issue number2
Publication statusPublished - 16 Jun 2021

Bibliographical note

© 2021 Amreen Bashir. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


  • Microbial contamination
  • used toothbrushes
  • toothbrush storage
  • Enterobacteria
  • Pseudomonas
  • E. coli
  • environmental


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