Analysis of ocular surface microbiome characteristics in patients with neurotrophic keratitis

Purpose This study aimed to comprehensively characterize the ocular surface microbiome (OSM) of neurotrophic keratitis (NK) patients using 16​​S rRNA gene amplicon sequencing and investigate how aberrant microbial metabolism affects NK pathogenesis. Methods A total of 15 NK patients and 30 healthy controls were enrolled, and conjunctival fornix swabs were processed for 16​​S rRNA gene amplicon sequencing. Bioinformatic analyses comprising alpha diversity, beta diversity, linear discriminant analysis effect size (LEfSe) analysis and PICRUSt2 functional annotation were performed to identify differentially abundant ocular surface taxa and enriched metabolic functions. Results Compared with healthy controls, NK patients exhibited significantly elevated alpha diversity and distinct clustering patterns in beta diversity. Subsequent compositional analysis identified 61 taxa at the phylum level, among which the relative abundance of Proteobacteria was markedly decreased in the NK group versus controls. At the genus level, 1,251 taxa were detected. LEfSe enrichment analysis screened out Acinetobacter , Cutibacterium , Staphylococcus , Corynebacterium , Methylobacterium-Methylorubrum as key biomarkers for NK. Functional prediction revealed widespread reductions in the predicted abundance of core metabolic pathways in the OSM of patients with NK, including fatty acid biosynthesis, aromatic amino acid biosynthesis, tricarboxylic acid cycle and UDP-N-acetylglucosamine biosynthesis. In contrast, pathways related to branched-chain amino acid biosynthesis and unsaturated fatty acid metabolism were significantly enriched in the NK group. Conclusion This study preliminarily links ocular surface pathological changes in NK patients to OSM and identifies its characteristic metabolic profile with suppressed core metabolism and elevated adaptive metabolism, providing a theoretical basis for further mechanistic research and clinical management of NK.