Abstract
Purpose :
The role of the ocular surface microbiome (OSM) and specific changes that occur in severe ocular surface diseases (OSDs) are currently unknown. We performed a prospective, observational study to characterize the OSM in several chronic OSDs including: Stevens-Johnson Syndrome (SJS), Graft versus Host Disease (GVHD), Floppy Eyelid Syndrome (FES), and Dry Eye Disease (DED), as well as healthy controls.
Methods :
Sterile cotton swabs were used to collect 3 samples (superior and inferior fornix and bulbar conjunctiva) per eye from 39 patients (76 eyes). DNA was extracted, amplified using multiple displacement amplification, sequenced using universal PCR primers targeting the V4 variable region of the 16S rRNA gene, and compared with negative control swabs. Only “positive” samples with more than 1000 reads were included in analysis. Positive samples were combined to constitute the OSM in each eye. Bacteria “presence” (Pr) was defined as ≥ 1% of reads and “dominance” (D) as the highest proportion of reads. Statistical analysis was performed using exact Wilcoxon rank sum tests and Fisher’s exact tests. Use of topical antibiotics, steroids, and bandage contact lenses (BCLs) was noted.
Results :
42 of 76 (55.2%) eyes had positive samples (10/16 healthy, 9/14 SJS, 2/14 GVHD, 8/16 FES, 13/16 DED). Among 10 healthy eyes, the microbiome was predominated by Lactobacillus (5 D; 2 Pr), Corynebacterium (3 D; 4 Pr), Streptococcus (2 D; 5 Pr), E. Shigella (7 Pr), Staphylococcus (6 Pr), Actinomyces (6 Pr), and Pseudomonas (5 Pr). Healthy eyes had an OSM consisting of a median (range) of 5 (1-7) bacteria, as compared to 3 (1-8) for patients with OSD (P=.008). Staphylococcus was the dominant bacteria for 5/9 patients with SJS, compared to 1/8 with FES, 1/3 DED, 0/2 GVHD and 0/10 controls (P=.017). Interestingly, 6/9 eyes with SJS were actively using BCLs. Healthy eyes had higher presence of Lactobacillus (70% vs 25%, P=.020) than patients with OSD. Patients with GVHD had relatively sterile ocular surfaces, as only 2/14 eyes had positive samples. Patients with FES and DED had similar OSMs with Corynebacterium being the most abundant bacteria.
Conclusions :
Patients with OSD appear to have less diverse OSMs than healthy patients with lower presence of Lactobacillus than controls. Lactobacillus may play a role in maintaining a healthy ocular surface.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.