Microbial Community Structure and Diversity in External Auditory Secretions from Healthy and Otomycosis Infected People

Abstract [Objective] To clarify the microbial community structure and diversity in external auditory secretions from healthy and otomycosis infected people. [Methods] The secretions of external auditory were collected from both healthy and otomycosis infected people. Total DNA of secretions were extracted and the high-throughput sequencing technology was employed to sequencing the sequence of the V3-V4 and ITS1 regions. Results were used for analyzing the of bacteria and fungi community structure and diversity. [Results] For the bacteria, 2539 and 1854 OTUs were detected in healthy group and diseased group respectively. Dramatically differences were observed among the samples within the group, and no statistical difference was obtained between healthy and diseased group. For the fungi, 569 OTUs were detected, which is much less than that in bacteria. Fungi were also detected both in the healthy and diseased group. However, unlike bacteria, significant statistical differences were observed in fungal community between healthy and diseased group. Basidiomycota was the main species in healthy group, while Aspergillus, which belongs to Ascomycota, was the dominant in diseased group. The percentage of Aspergillus in 8 of 10 samples in diseased group was higher than 90%, while Aspergillus in healthy group were mostly between 0.00% to 0.30%. In addition, network analysis of the correlation between fungi and bacteria was performed. Although there was a positive correlation between the abundance of Malassezia and several bacteria, no correlation was observed between the changes in the abundance of other fungi and bacteria. [Conclusion] There are various bacteria and fungi in the external auditory canal of both healthy and otomycosis infected people. Although bacterial community did not change significantly due to the mycotic infection of the ear, fungi community changed significantly, and Aspergillus were the main pathogens in the diseased group. In addition, the change of communities in bacteria and fungi is independent during the pathogenesis of otomycosis, and the change of fungi may not have effect on the bacterial community structure.