Rapid Genetic Test Identifies Hidden Infections in Critical Pediatric

A new diagnostic approach is transforming intensive care for children by identifying infections that traditional methods often overlook. Known as metagenomic testing, this method analyzes all genetic material within a respiratory sample, allowing clinicians to detect thousands of potential pathogens, including bacteria, fungi, and viruses simultaneously. Unlike conventional techniques, which have remained largely unchanged since the Victorian era and require doctors to guess which specific organism they are searching for, this technology provides a comprehensive overview of the genetic landscape. By contrast, the most common method of identifying bacteria is by trying to culture them in Petri dishes, a technology that has been used since Victorian times.

The impact of this technology was evident in the case of 10-year-old Willow Crowther, who was admitted to the paediatric intensive care unit at London’s Great Ormond Street Hospital (GOSH) in March. Suffering from severe pneumonia that resulted in seizures and multiple cardiac arrests, Willow’s condition was dire; her family was warned she had only a 50% chance of survival. Her mother, Stacey Moore, recalled being told by the consultant that the family should prepare to say their final goodbyes due to the severity of her condition. Respiratory samples from more than 100 critically ill young patients at London’s Great Ormond Street Hospital (GOSH) were sent for what is known as metagenomic testing., external.

Metagenomic testing revealed that Willow was battling a drug-resistant bacterial infection, prompting doctors to switch her to the correct antibiotic immediately. Stacey emphasized the critical role of this diagnostic tool, stating that its availability for her daughter was paramount and ultimately saved her life. Willow’s father, Russ, echoed these sentiments, expressing deep gratitude for what he described as a miraculous recovery. Following the adjustment in her treatment, Willow stabilized and eventually recovered, later celebrating her 10th birthday in August. This is how critical and in how much danger she was of passing away. It’s a miracle she’s here and we’re extremely grateful for that,” added Willow’s dad, Russ. With the right treatment, Willow was eventually able to recover from her infection, but needed several months in hospital.

A study published in the Lancet Microbe evaluated the use of this testing on 122 critically ill children at GOSH during 2024 and 2025. The results demonstrated that the test identified approximately nine out of ten bacteria and viruses, along with all fungal pathogens in the samples tested. In 25% of cases, these findings directly influenced clinical decisions, such as initiating, modifying, or halting antibiotic treatments. Dr. Sam Ray, a consultant in paediatric intensive care medicine at GOSH and a co-author of the study, explained that the ability to stop unnecessary treatment is vital for combatting the global rise of antimicrobial resistance. During a study in 2024-5 metagenomic testing was used on 122 critically ill children in the paediatric intensive care unit (ICU) at GOSH. Get children on the right treatment and stop antibiotics when we know they aren’t going to work, the study has helped us to spot infections we would have missed.

Beyond immediate patient care, the testing identified 50 organisms that routine diagnostics had failed to detect, suggesting a potential role for the technology as an early warning system against novel infections. Dr. Julianne Brown, head of the GOSH Metagenomics Service and a co-senior author, noted that the service is now being integrated into approximately 30 intensive care units across the UK for both pediatric and adult patients. She added that such tools could prove essential in identifying mystery pathogens that might pose future pandemic threats, enabling authorities to implement necessary measures rapidly. The project builds upon earlier successful trials conducted at Guy’s and St Thomas’ NHS Trust, which initially utilized metagenomics for adult respiratory infection screening. Meaning better outcomes for some critically ill patients, metagenomics can detect infections that standard tests miss. If there was to be a new mystery pathogen that could be a cause of the next pandemic, we would detect that very quickly and put the right measures in place, in the future.