Abstract
Purpose :
The ocular surface microbiome (OSM) is a unique environment. Relatively little is known about the composition of this environment in children, particularly in comparison to the neighboring microbiomes of the nose and throat. We performed a prospective, observational, cross-sectional study to explore the differences between the ocular surface and the nasal and pharyngeal microbiomes.
Methods :
We enrolled 50 children under 18 years of age seen in the pediatric ophthalmology department at a university-based eye institute. The mucosal surfaces of both eyes, nose and throat were swabbed with a forensic-quality swab and placed in a collection media. One-half of the media was plated for culture and the other half underwent DNA extraction and 16S sequencing. Specimens were excluded if active infection was present. Outcome measures included culture and 16S speciation, alpha diversity (number of organism types within a sample; measure - Observed and Shannon Diversity indices), and beta diversity (comparison of microbial composition between samples; measure - ordination).
Results :
50 patients (62% male) were enrolled. The average age was 37 months (range 1-168 months). Ocular cultures were positive in 47 eyes of 30 patients, and four eyes grew >1 species. Of the 52 isolates, coagulase negative Staphylococcus was most common (35%), which was consistent with the results from 16S sequencing. Although the ocular microbiome was similar between eyes, the ocular, nasal and pharyngeal microbiomes differed significantly (p=0.001). Nasal samples did not differ significantly from ocular samples (p=0.80); however, throat samples had significantly higher observed diversity [mean (SD) 88.5 (17.7), p=0.016], but statistically similar Shannon diversity [106 (25.8), p=0.42] when compared to ocular samples. The observed diversity index between the nose and throat approached statistical significance (p=0.08), however the Shannon diversity was not significantly different (p=0.21). Streptococcus was the predominant species in the throat, which differed from the ocular and nasal samples in which Staphylococcus was dominant (p=0.0002).
Conclusions :
16S sequencing is a useful tool in evaluating the ocular, nasal and pharyngeal microbiomes in children, revealing significant differences between the microbiomes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.