Contamination Potential of Toothbrushes with Streptococci, Enterobacteriaceae and Candida albicans

Concern that micro-organisms on used toothbrushes might cause contamination and lead to spread of oral diseases exists since 1920. Several studies have indicated that used brushes with jagged bristle ends retain micro-organisms and therefore can act as reservoir for infection of the oral cavity. Objectives: This study determined the number of organisms on new toothbrushes when taken from the sealed packages and then determined the contamination potential on new and used toothbrushes. Methods: The number of micro-organisms on new sealed toothbrushes (4 different brands) were determined by rinsing the brushes and preparing dilution series that was plated onto selective agar. The new brushes was then contaminated with known concentrations of Streptococcus mutans (ATCC 12575), Escherichia coli (ATCC 10536), Enterococcus feacalis (ATCC 49474) and Candida albicans (ATCC 10231). Contamination was determined by rinsing the toothbrushes in an ultrasonic water bath with sterile Ringers solution and plating serial dilutions onto selective agar. The toothbrushes were then mounted in a device and brushed against a rough surface until visible wear of the brushes and jagging of the bristles were observed. These brushes were then once again contaminated with known concentrations of the test organisms and contamination was determined as described previously. Results: No micro-organisms were found on sealed toothbrushes. On new toothbrushes the contamination potential with micro-organisms was significantly lower (p<0.05) than on visibly used brushes with jagged bristles. Conclusion: Used toothbrushes contaminate more readily with micro-organisms and the organisms seem to stick to the jagged bristles better than to new brushes.