Corneal bacterial microbiome in patients with keratoconus using next-generation sequencing–based 16S rRNA gene analysis

• Published in: Experimental eye research Vol. 228; p. 109402
• Main Authors: Tunç, Uğur, Çelebi, AR Cenk, Ekren, Berkay Yekta, Yıldırım, Yusuf, Kepez Yıldız, Burçin, Okullu, Sinem Öktem, Sezerman, Osman Uğur
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2023
• Subjects: Bacteria; Cornea; Corneal ectasia; Corneal microbiome; Genes, rRNA; High-Throughput Nucleotide Sequencing; Humans; Keratoconus; Keratoconus - microbiology; Microbiota - genetics; Next–generation sequencing; Ocular microbiome; RNA, Ribosomal, 16S - genetics; Next–generation sequencing; Corneal ectasia; Corneal microbiome; Keratoconus; Ocular microbiome
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1016/j.exer.2023.109402

To investigate the corneal bacterial microbiome in patients with keratoconus using next-generation sequencing and develop a new perspective on the pathogenesis of the disease. This prospective observational study included 10 patients with keratoconus who underwent corneal crosslinking procedure and 10 healthy controls who underwent photorefractive keratectomy. Patients included in the study were aged 18 years or older. The demographic and clinical characteristics of participants were recorded. Corneal epithelial samples were collected between March 2021 and June 2021. Isolated bacterial DNA from corneal epithelial samples was analyzed using 16 S ribosomal RNA gene analysis. The relative abundance rates at the phylum and genus levels were calculated. Alpha diversity parameters were assessed. Eleven phyla and 521 genera of bacteria were identified in all participants. At the phylum level, Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were most abundant in both groups. There were no statistical differences between the two groups except Bacteriodetes (p < 0.05). At the genus level, the relative abundance rates of twenty bacteria were significantly different between keratoconus and healthy corneas (p < 0.05). Aquabacterium was the most abundant genus in patients with keratoconus, while Shigella was the most abundant genus in healthy controls. Alpha diversity parameters were lower in patients with keratoconus, although the difference did not reach statistical significance (p > 0.05). Our preliminary study revealed that there are similarities and differences in the corneal microbiome between keratoconus and healthy individuals. Further research is required on the relationship between the abnormal corneal microbiome composition and the pathogenesis of keratoconus. •The presence of 11 phyla and 521 genera of bacteria was identified in the corneal microbiome of all participants.•The most abundant phyla were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, respectively.•Aquabacterium, Staphlococcus, and Paraburkholderia were present in all corneal samples.•The relative abundance rates of 20 genera were significantly different between keratoconus and healthy corneas.•Our preliminary study suggested that the corneal microbiome in keratoconus is distinct from healthy corneas.