A Tear-Based Approach for Rapid Identification of Bacterial Pathogens in Corneal Ulcers Using Nanopore Sequencing

Area of Science:

• Ophthalmology
• Microbiology
• Genomics

Background:

• Corneal ulcers are a major cause of vision loss, necessitating rapid and accurate pathogen identification for effective treatment.
• Traditional methods like corneal scraping and culture have limitations, including high false-negative rates and difficulty in detecting certain bacteria.

Purpose of the Study:

• To evaluate the efficacy of Nanopore sequencing technology for direct detection and identification of bacterial pathogens from tear samples in patients with corneal ulcers.
• To compare the performance of this non-invasive sequencing method against conventional corneal scraping and culture techniques.

Main Methods:

• A prospective observational study involving ten participants diagnosed with corneal ulcers.
• Tear samples were collected non-invasively using Schirmer strips.
• Bacterial 16S rRNA gene was amplified via PCR from tear samples, followed by Nanopore sequencing for species identification and comparison with traditional culture results.

Main Results:

• Bacterial DNA was detected in 8 out of 10 tear samples using Nanopore sequencing.
• The sequencing method accurately identified bacteria in all samples positive by culture and detected pathogens in samples negative by culture.
• Nanopore sequencing identified bacteria in cases where traditional cultures were unobtainable due to sample size, revealing potentially missed pathogens.

Conclusions:

• PCR amplification of 16S rRNA from tear samples followed by Nanopore sequencing is a viable and non-invasive approach for identifying bacterial pathogens in corneal ulcers.
• This method provides diagnostic value comparable to traditional cultures, with the added benefit of detecting difficult-to-culture organisms.
• The technique enhances understanding of the corneal ulcer microbiome, potentially leading to improved treatment strategies.