Oropharyngeal Microbiome in Obstructive Sleep Apnea: Decreased Diversity and Abundance

Study Objectives: To explore and analyze diversity and abundance of oropharyngeal microbiota in patients with obstructive sleep apnea (OSA). Methods: This was a cross-sectional study. Middle-aged men, suspected to have OSA, referred to full-night polysomnography, and willing to provide oropharyngeal swab samples, were consecutively enrolled. OSA severity was assessed by apnea-hypopnea index (AHI) as non-OSA (AHI < 5 events/h) and OSA (AHI >= 15 events/h). Bacterial DNA of oropharyngeal samples was extracted and quality test performed. Oropharyngeal microbiota was analyzed using 16S ribosomal DNA (rDNA) sequencing, and bioinformatic analysis carried out after sequencing. Results: Samples from 51 men (25 in the non-OSA group and 26 in the OSA group) were sent for examination. Of these, 40 samples were found to have sufficient concentration of DNA and were analyzed for bioinformatics. In alpha diversity analysis, the OSA group exhibited significantly lower sobs (198.33 +/- 21.71 versus 216.57 +/- 26.21, P = .022), chao (221.30 +/- 26.62 versus 243.86 +/- 26.20, P = .014), ace (222.17 +/- 27.15 versus 242.42 +/- 25.81, P = .028) and shannon index (3.14 +/- 0.23 versus 3.31 +/- 0.26, P = .035), suggesting a reduction in microbial species diversity. We further divided participants into non-OSA, moderate OSA, and severe OSA groups and observed a significant decrease in the bacterial biodiversity of OSA groups compared with the non-OSA group, with the most significant decrease occurring in the moderate OSA group. Principal coordinate analysis showed two extremely different oropharyngeal microbial communities in non-OSA and OSA groups. More interestingly, proportion of Neisseria was slightly higher in the severe OSA group (20.64%), followed by the moderate OSA and non-OSA groups (12.57% and 9.69%, respectively). Glaciecola was not detected in the OSA groups compared to the non-OSA group (0 versus 0.772 +/- 0.4754, P < .001). Conclusions: Middle-aged men with OSA showed less oropharyngeal species diversity and altered abundance, on which further confirmation is warranted.