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Updated: Nov 15, 2025
Author Spotlight: Studying Behavior of Acanthamoeba to Develop Targeted Strategies for Preventing Acanthamoeba Keratitis
Published on: September 20, 2024
Intracellular Microbiome Profiling of the Acanthamoeba Clinical Isolates from Lens Associated Keratitis
Yu-Jen Wang1, Sung-Chou Li2, Wei-Chen Lin1,3,4
1Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 70101 Tainan, Taiwan.
Abstract:
Acanthamoeba act as hosts for various microorganisms and pathogens, causing Acanthamoeba Keratitis (AK). To investigate the association between endosymbionts and AK progression, we performed a metagenomics study to characterize the intracellular microbiome from five lenses associated with AK isolates and standard strains to characterize the role of ocular flora in AK progression. The used clinical isolates were axenic cultured from lenses associated with AK patients. AK isolates and standard controls such as 16S ribosomal RNA sequencing techniques were used for analysis. The microbiome compositions and relative abundance values were compared. The orders of Clostridiales and Bacteroidales presented major populations of intracellular microbes belonging to all isolates. Comparison of the different source isolates showed that most of the abundance in keratitis isolates came from Ruminococcus gnavus (121.0 folds), Eubacterium dolichum (54.15 folds), Roseburia faecis (24.51 folds), and Blautia producta (3.15 folds). Further analysis of the relative abundance data from keratitis isolates showed that Blautia producta was positively correlated with the disease course. In contrast, Bacteroides ovatus was found to be abundant in early-stage keratitis isolates. This study reveals the abundant anaerobic Gram-positive rods present in severe keratitis isolate and characterize the association between Acanthamoeba and ocular flora in AK progression.
Insights
Acanthamoeba keratitis (AK) progression is linked to specific microbial communities within the parasite. Anaerobic Gram-positive rods, particularly Blautia producta, are abundant in severe AK cases, suggesting a role in disease severity.
Area of Science:
- Microbiology
- Ophthalmology
- Genomics
Background:
- Acanthamoeba species are protozoa that can harbor microorganisms, leading to Acanthamoeba keratitis (AK).
- The role of the intracellular microbiome in AK pathogenesis remains incompletely understood.
- Understanding the ocular flora associated with Acanthamoeba is crucial for AK progression studies.
Purpose of the Study:
- To characterize the intracellular microbiome of Acanthamoeba isolates from keratitis patients.
- To investigate the association between specific microbial endosymbionts and the progression of Acanthamoeba keratitis.
- To identify the role of ocular flora in the pathogenesis of AK.
Main Methods:
- Metagenomics sequencing was employed to analyze the microbiome composition of five Acanthamoeba keratitis isolates.
- 16S ribosomal RNA sequencing was used for microbial identification and relative abundance analysis.
- Clinical isolates were axenically cultured from patient lenses for microbiome characterization.
Main Results:
- The orders Clostridiales and Bacteroidales constituted the major populations of intracellular microbes across all isolates.
- Significant abundance of Ruminococcus gnavus (121.0-fold), Eubacterium dolichum (54.15-fold), Roseburia faecis (24.51-fold), and Blautia producta (3.15-fold) was observed in keratitis isolates.
- Blautia producta showed a positive correlation with disease severity, while Bacteroides ovatus was more abundant in early-stage keratitis.
Conclusions:
- Acanthamoeba keratitis is associated with a distinct intracellular microbiome, dominated by anaerobic Gram-positive rods.
- Specific bacterial species, such as Blautia producta, may play a significant role in the progression and severity of Acanthamoeba keratitis.
- This study highlights the complex interplay between Acanthamoeba, its endosymbionts, and the ocular environment in AK pathogenesis.
