Researchers at Great Ormond Street Hospital (GOSH) in London have used a metagenomic diagnostic test to identify infections in critically ill children that traditional testing methods often missed. The study, published in The Lancet Microbe, involved respiratory samples from 122 patients in the pediatric intensive care unit. Unlike standard tests that require clinicians to pre-select specific pathogens for testing, metagenomics sequences all genetic material in a sample to identify bacteria, viruses, and fungi simultaneously.
The study followed earlier trials at Guy’s and St Thomas’ NHS Trust, which utilized similar technology for respiratory infections in adult patients. Traditional methods typically rely on Petri dish cultures, a technique used since the Victorian era, or PCR tests which require doctors to specify which virus or bacteria they are looking for. The metagenomic approach at GOSH was able to identify approximately 90% of bacteria and viruses and 100% of fungi present in the samples.
In one documented case, the test was used for 10-year-old Willow Crowther, who was admitted to the hospital with pneumonia in March. The test identified a drug-resistant bacterial infection that had not responded to her initial antibiotic treatment. Following the results, doctors changed her prescription, and she recovered after several months in the hospital. Her mother, Stacey Moore, stated that the availability of the test was paramount to her survival.
According to the study, the metagenomic results influenced prescribing decisions in 25% of the cases. This included starting new treatments, stopping ineffective ones, or switching antibiotics. Dr. Sam Ray, a consultant in pediatric intensive care at GOSH, stated that the test spotted 50 organisms that routine diagnostics missed. Ray noted that removing unnecessary treatments is a factor in addressing antimicrobial resistance.
The concrete impact for patients is a faster transition to targeted medication. In 25% of the study's cases—or roughly one out of every four children tested—doctors changed the patient's treatment plan based on the results. This could mean avoiding the side effects of unnecessary antibiotics or receiving a life-saving drug for a resistant strain earlier in the illness. The clinical findings suggest that patients could see these changes in their treatment plans within 24 hours of a sample being taken at participating facilities.
On a broader scale, the use of metagenomics sets a precedent for how hospitals monitor emerging health threats. Dr. Julianne Brown, head of the GOSH Metagenomics Service, stated the tool could be used to detect unknown pathogens that might pose a pandemic threat. By identifying thousands of different pathogens at once, health systems may be able to implement containment measures more quickly. The rollout to 30 UK sites is currently underway, though specific completion dates for the full expansion were not reported.