A mystery infection, that affected a woman for five years, was identified using a novel genomic test that led to targeted treatment and full recovery of the patient.

Dr Ellie Irwin was diagnosed with right eye inflammation in 2019, yet no treatment improved her condition and her symptoms worsened. Over five years, traditional tests for common infections always came back negative, which led her clinical team at Moorfields Eye Hospital, London, to have a sample from Dr Irwin's eye tested using a novel approach called 'metagenomics'. This sequencing service, provided by Great Ormond Street Hospital for Children (GOSH), London, screens for all possible pathogens simultaneously, rather than looking for a specific bacteria or virus. Such testing can detect a broad range of infections by matching both the DNA and RNA from a sample to genomic sequences of pathogens from a database.

'We have been developing our metagenomics service at GOSH and University College London (UCL) for over ten years now and we are incredibly proud to be the first UK accredited service… We are now able to offer this vital genomic testing to patients around the country, and it is amazing to see the impact it is already having for patients like Ellie,' said Professor Judith Breuer from UCL and honorary consultant virologist at GOSH.

The test showed Dr Irwin's right eye had a very specific strain of leptospirosis, an extremely rare bacterial infection that had not been detected during previous testing. After the diagnosis, she received a three-week antibiotic treatment specifically targeted for her infection. Dr Irwin eventually recovered from all symptoms once the infection was fully treated, has since returned to living a normal life and has expressed immerse gratitude to the people that helped her.

'I had really just reached my breaking point; my team had tried every test to find a cause and the intensive treatments and multiple appointments were severely impacting my life. I had got to the point that I began to discuss with my team my wish to have the affected eye removed,' said Dr Irwin. 'No words can express my gratitude to the teams who helped me get the answers I needed and never gave up on me.'

The genomic test was developed by Professor Breuer's research team at UCL GOS Institute of Child Health and the clinical teams within GOSH. A two-year pilot trialling the genomic test in identifying the cause of respiratory infections in under seven hours received funding from NHS England and the Department for Science, Innovation and Technology in January 2024 (see BioNews 1225). The test is now available at up to 30 sites across the UK.

The test can be used for identifying infections from locations in the body where the presence of an infection is less common – such as the central nervous system, the brain, the liver or, as in Dr Irwin's case, in the fluid found behind the eye.

'We are excited about the opportunities this opens up and have already initiated a clinical trial on the use of metagenomics for hard-to-diagnose eye infections,' Professor Carlos Pavesio, consultant ophthalmologist at Moorfields Eye Hospital, said.

UCL and GOSH are collaborating in national projects to use metagenomics for faster diagnosis in critical care and in other hard-to-diagnose infections.