Metagenomic Profiling of Ocular Surface Microbiome Changes in Meibomian Gland Dysfunction

Abstract

Background: Ocular surface microbiome changes can affect meibomian gland dysfunction (MGD) development, which in turn may increase the risk of tissue infection. To delineate what these changes are, we used shot-gun metagenomic analysis to determine if there are differences between the microbial communities in ocular sites surrounding the meibomian gland in healthy and patients afflicted with MGD. This comparison entailed comparing the microbe content in different microbiomes of the eyelid skin, conjunctiva and meibum with those from the same locations in healthy individuals (HC) and those with this disease. Results: The meibum bacterial content of these microbiomes was different in these two different types of individuals. Almost all of the most significant taxonomic changes in the meibum microbiome of these individuals with MGD were also present in their eyelid skin, but not in the conjunctiva. Such site-specific microbe pattern changes accompany increases in the gene expression levels controlling carbohydrate and lipid metabolism. Most of the microbiomes in MGD disease possess a microbe population capable of metabolizing benzoate. Interestingly, microbe preponderance seemed to be less in patients afflicted with more severe MGD. Nevertheless, pathogens known to underlie ocular infection were evident in these patients. In meibum samples from HC, Pseudomonas fluorescens was present in more than 90% of the samples. Cupriavidus metallidurans and Pseudomonas putida had a positive rate over 50%. MGD meibum contained instead an abundance of Campylobacter coli, Campylobacter jejuni, and Enterococcus faecium pathogens, which were almost absent from HC. Functional annotation indicated that in the microbiomes of MGD meibum their capability to undergo chemotaxis and display immune evasive virulence and mediate Type IV secretion was different than that in the microbiomes of meibum isolated from HC. Conclusions: MGD meibum contained distinct microbiota different from HC, and MGD meibum microbiome community population was much smaller than in the HC group. Profiling differences in the meibum microbiome makeup between HC and MGD patients may uncover unique targets for improved treatment of this disease.

Analysis of Conjunctival Sac Microbiome in Dry Eye Patients With and Without Sjögren's Syndrome

“…In previous studies, the richness of the conjunctival sac microbiome in patients with dry eyes was inconsistent. While some studies revealed an increased number of bacteria (18,19), most studies were in accordance with our study that patients with dry eyes have diminished ocular surface microbiome diversity (20)(21)(22)(23). In studies regarding SS, bacterial diversity was diminished both for the oral mucosa (24) and the ocular surface (23).…”

Metagenomic profiling of ocular surface microbiome changes in Demodex blepharitis patients

“…YG1 is a lignin model dimer-metabolizing bacterium newly isolated from sediment and has never been reported on the ocular surface (Ohta, 2018). However, the genus Sphingobium had been reported to be abundant in the MGD meibum (Zhao et al, 2020). Interestingly, the correlation between species abundances and clinical parameters in the DB group showed higher RAs of Delftia tsuruhatensis, Sphingobium sp.…”

Metagenomic Analysis Reveals the Heterogeneity of Conjunctival Microbiota Dysbiosis in Dry Eye Disease

“…Emerging evidence suggests that alteration in the ocular surface microbiota is involved in DED (Gomes et al, 2020). However, the majority of prior studies have focused on specific types of DED, such as MGD and Sjögren's syndrome (de Paiva et al, 2016;Watters et al, 2017;Jiang et al, 2018;Dong et al, 2019;Zhao et al, 2020). In contrast, patients with other types of DED were less represented, especially those with a mixed type of diagnosis.…”