Assessment of bacterial contamination of toothbrushes using Illumina MiSeq

Abstract

Toothbrushes are commonly used to remove dental plaque, and the presence of bacteria on toothbrushes has been previously reported. Toothbrushes are contaminated by many bacteria after brushing, and contaminated toothbrushes can cause oral and systemic diseases. Toothbrush contamination was studied previously, but the study was limited because it only identified specific bacteria using a general bacterial culture method. To overcome this limitation, we used Illumina sequencing to identify microorganisms present on toothbrushes. Toothbrush samples were divided into two groups according to the storage location: a toothbrush stored in the office or a toothbrush in the bathroom. Samples were sequenced using Illumina sequencing. Enterococcus (30.76%), Pseudomonas (21.85%), Streptococcus (14.94%), and Lactobacillus (5.15%) were the predominant bacteria found on the toothbrushes stored in the office. Streptococcus (19.73%), Pseudomonas (16.08%), Enterococcus (8.16%), and Neisseria (7.04%) were the predominant species on the toothbrushes stored in the bathroom. In addition, 36.29% of the bacteria on the toothbrushes stored in the office and 33.77% of the bacteria on the toothbrushes stored in the bathroom were identified as potentially pathogenic bacteria. Both groups included microorganisms such as Streptococcus, Actinomyces, Porphyromonas, and Fusobacterium that are related to oral disease. This study confirmed the high contamination rate of used toothbrushes and demonstrated that repeated use of toothbrushes could lead to contamination by pathogenic bacteria.