Microbiome of the healthy external auditory canal

Our objective was to investigate the microbiota of the healthy external auditory canal (EAC) culture-independently and to evaluate the usefulness of the swabbing method in collecting EAC microbiota samples. Samples were harvested with DNA-free swabs from the EACs of 50 healthy, asymptomatic working-age volunteers. Amplicon sequencing of the 16S rRNA gene was used to characterize the microbial communities in the samples. We found the swabbing method feasible for EAC microbiota sample collection. We excluded 4 samples from our analyses due to recent antimicrobial treatment, leaving 46 samples for our comparisons (32 female and 14 male subjects). The most common bacteria in the microbiome of the healthy EAC were Staphylococcus auricularis, Propionibacterium acnes, Alloiococcus otitis and Turicella otitidis. The EAC microbiota seems more diverse and individualized than previously thought, possibly including genera that have been perceived pathogenic, such as Pseudomonas. Additionally, our results suggested that ear cleaning habits may alter the EAC microbiome.