Abstract
Purpose :
To determine whether individuals with mild to moderate meibomian gland dysfunction (MGD), either with or without lacrimal dysfunction (LD), have a different microbial composition compared to healthy individuals, using 16S rRNA gene sequencing.
Methods :
Sixty participants consisting of three cohorts (MGD, MGD with LD [MGD+LD] and healthy controls) were enrolled into a prospective study which involved three sampling visits (baseline, 1-month, 3-months). Swabs were taken bilaterally from the inferior conjunctiva and eyelid margin and the microbial DNA extracted, the V3-V4 region of the 16S rRNA gene amplified and then sequenced on the MiSeq platform. Negative controls (blank, unused swabs) were processed and sequenced as per test samples. Sequences were quality filtered using the UNOISE algorithm implemented in USEARCH. A linear regression filter was used to identify contaminant taxa in the negative control samples which were then removed from the patient sample data
Results :
There was a reduction in the estimated number of taxa on the conjunctiva (P = 0.025) and eyelid margin (P = 0.0009) of participants with MGD+LD compared to the MGD group and healthy controls. The eyelid margin of the control group also had significantly higher bacterial diversity compared to the MGD (P=0.0031) and MGD+LD (P = 0.008) groups.
On the conjunctiva, bacteria belonging to the species Corynebacterium kroppenstedtii and Corynebacterium macginleyi were more abundant in the MGD samples while bacteria belonging to Pseudomonas azotoformans and Pseudomonas oleovorans were more abundant in the MGD+LD samples (P < 0.05). On the eyelid margin, bacteria belonging to the species Corynebacterium accolens, Corynebacterium macginleyi and Corynebacterium simulans were more abundant in the MGD lid samples while bacteria belonging to the species Pseudomonas putida was found to be more abundant in the MGD+LD samples (P < 0.05).
The bacterial community structure of the MGD+LD group was significantly different to the MGD and control groups for the conjunctiva (P=0.027) and eyelid margin (P=0.006).
Conclusions :
There were differences in the bacterial richness, diversity and community structure of the conjunctiva and eyelid margin between individuals with meibomian gland dysfunction (with and without lacrimal dysfunction) compared to healthy controls, suggesting that microbial dysbiosis may have a role in the pathogenesis of MGD.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.