Distribution and Diversity of Ocular Microbial Communities in Diabetic Patients Compared with Healthy Subjects

Abstract

Purpose: The aim of this study was to identify differences in the major (core vs. variable) microbial genera of human subjects with and without diabetes. Methods: Bacterial 16S rRNA genes obtained from conjunctival swabs of 19 healthy subjects and 30 diabetic patients were sequenced using the Illumina MiSeq platform, and the sequencing data were analyzed using QIIME 1.9.1. To elucidate the microbial diversity in the ocular surface (OS), test programs from various bioinformatics domains were used. Results: Diversity index and rarefaction analysis showed that the microbial community of the diabetic patients was more diverse than that of the healthy subjects. Proteobacteria, Firmicutes, Actinobacteria, Cyanobacteria and Bacteroidetes were the dominant taxa present in the OS, and there was a significant difference in the relative abundance of the bacterial phyla between the diabetic patients and control subjects. Proteobacteria were more abundant in the diabetic group, whereas Firmicutes was more abundant in the control group. Analysis of bacterial taxa at the genus level showed that the core microbiome of diabetic patients comprised Acinetobacter, Burkholderia, Sphingomonas, and Ralstonia, whereas that of the controls comprised Bradyrhizobiaceae, Staphylococcus, Corynebacterium, Pseudomonas, Novosphingobium, Neisseriaceae, and Acinetobacter. Conclusions: There was a significant difference in the microbial community composition between diabetic patients and healthy subjects. A high abundance of Acinetobacter in the OS of diabetic patients may arise from the unique characteristics of the OS compared with those of other organ surfaces.