Analysis of Conjunctival Sac Microbiome in Dry Eye Patients With and Without Sjögren's SyndromeOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
Conjunctival sac swab samples from 23 eyes with Sjögren's syndrome-associated dry eye (SSDE), 36 eyes with non-Sjögren's dry eye (NSSDE), and 39 normal control eyes were compared.
How was it studied?
16S rRNA gene V3-V4 region sequencing on an Illumina MiSeq platform was analyzed with QIIME. Alpha diversity used Chao1 and Shannon indexes; beta diversity used PCoA and PLS-DA.
What did they find?
Shannon diversity was lower in both dry eye groups than controls (P = 0.020 SSDE, P = 0.029 NSSDE), and beta diversity differed across all three groups. The top phyla (Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, Cyanobacteria) and top genera (Acinetobacter, Staphylococcus, Bacillus, Corynebacterium, Clostridium_sensu_stricto_1) were shared, but relative abundance varied. The Firmicutes/Bacteroidetes ratio was 6.42 in controls, 7.31 in NSSDE, and 9.71 in SSDE, higher in SSDE than both other groups (P = 0.038 vs NC, P = 0.048 vs NSSDE).
Why it matters
Reduced conjunctival microbial diversity and a shifted Firmicutes/Bacteroidetes ratio distinguish Sjögren's-associated dry eye, suggesting ocular surface dysbiosis tracks with underlying autoimmune disease rather than dry eye alone.