A CUTTING-EDGE metagenomic test has saved the eyesight of a 29-year-old Bristol doctor by identifying a rare bacterial infection that had eluded diagnosis for five years, demonstrating the transformative potential of genomic sequencing in clinical practice.
Ellie Irwin first developed persistent inflammation in her right eye in 2019, resulting in blurred vision and significant disruption to her life and career. Despite exhaustive testing and aggressive treatment-including hourly steroid eye drops, immunosuppressants, and even cataract surgery-her condition worsened, leading her to consider having her eye removed15. Standard diagnostic tools, including cultures and PCR tests, repeatedly failed to identify an infectious cause, and an autoimmune condition was suspected. As a last resort, her clinical team at Moorfields Eye Hospital arranged for a sample of fluid from her eye to be analysed by the UK’s only accredited metagenomics laboratory at Great Ormond Street Hospital (GOSH). Metagenomics uses high-throughput sequencing to detect all potential pathogens in a sample, without prior assumptions236. In Ellie’s case, the test identified a rare strain of leptospirosis-likely contracted while swimming in the Amazon in 2018-which was rapidly cured with a three-week course of targeted antibiotics, restoring her sight in time for her wedding.
This case highlights how metagenomics can revolutionise the diagnosis of complex or atypical infections, especially when conventional methods fail. In clinical practice, the ability to identify unexpected pathogens in a single, untargeted test can lead to faster, more accurate diagnosis and tailored treatment, potentially preventing irreversible harm such as vision loss. As costs fall and speed increases, metagenomics is likely to become a first-line diagnostic tool for infections in sterile sites, not only improving outcomes for individual patients but also enhancing public health surveillance and antimicrobial stewardship. Future considerations include integrating metagenomics into routine clinical workflows, expanding access, and continuing research to optimise sensitivity, specificity, and cost-effectiveness for widespread use
Reference
BBC. Metagenomics test saves woman’s sight after mystery infection. Available at: https://www.bbc.co.uk/news/articles/czx45vze0vyo. Last accessed: 2 May 2025.
