Same-day test helps doctors detect hidden infections in critically ill children

A groundbreaking same-day test has successfully identified hidden and drug-resistant infections in critically ill pediatric patients.

Respiratory samples from over 100 critically ill children at London's Great Ormond Street Hospital (GOSH) were subjected to metagenomic testing.

This advanced method can recognize bacteria, viruses, and fungi from a single sample, often impacting the medical decisions made by healthcare professionals.

Metagenomics enhances the detection of infections that may elude standard testing protocols, resulting in improved outcomes for several critically ill patients.

'The test... saved her life'

In March, 10-year-old Willow Crowther experienced a life-threatening episode of pneumonia, leading to a seizure and multiple cardiac arrests.

Hailing from Kent, Willow was admitted to the intensive care unit at GOSH, where her mother, Stacey Moore, was informed that her daughter faced a 50% chance of survival.

"The consultant said... we needed to gather our family to say goodbye to her. This illustrated the severity of her condition," recalled Stacey.

Utilizing metagenomics—a diagnostic approach that sequences all genetic material present—GOSH's medical team was able to uncover that Willow had a drug-resistant bacterial infection necessitating a different antibiotic than the one initially prescribed.

"The availability of this test was crucial. It saved her life," Stacey remarked.

"It's a miracle she's here, and we are profoundly grateful," added Willow's father, Russ.

With appropriate treatment, Willow ultimately recovered from her infection, although her hospital stay extended for several months.

She represents just one of many patients at the hospital benefiting from this innovative testing approach.

Study and Results

In a study conducted between 2024 and 2025, metagenomic testing was applied to 122 critically ill children in the pediatric intensive care unit (ICU) at GOSH.

The findings have been documented in the Lancet Microbe.

Metagenomic testing analyzes all genetic material in a sample, identifying thousands of potential pathogens.

In contrast, the most prevalent method of bacterial identification relies on culturing samples in Petri dishes—a technique rooted in Victorian practices.

Another commonly used test, PCR, can detect specific viruses and bacteria, but it requires that clinicians pre-specify their target.

At GOSH, metagenomic testing identified around 90% of bacteria and viruses present, in addition to all fungi in the samples assessed.

In approximately a quarter of these instances, the results shifted prescribing decisions—whether to initiate, halt, or modify an antibiotic treatment.

Expert Perspective

Dr. Sam Ray, a consultant in pediatric intensive care medicine at GOSH and co-author of the study, noted that traditional testing requires clinicians to hypothesize which infection they are investigating.

"This study has enabled us to identify infections that would have otherwise remained undetected, facilitating timely and appropriate treatment for children, as well as the cessation of ineffective antibiotic therapies," he explained.

"Eliminating unnecessary treatments is crucial in combating the growing issue of antimicrobial resistance."

Additionally, GOSH's metagenomic testing detected 50 organisms that standard diagnostics did not identify, underscoring its potential as an early warning mechanism for emerging infections.

Dr. Julianne Brown, head of the GOSH Metagenomics Service and co-senior author of the study, stated that the novel testing method is gradually being introduced to approximately 30 intensive care units across the UK, which cater to both adults and children.

"This tool could be pivotal in identifying new infections that may pose a pandemic risk," she remarked.

"In the event of a new unknown pathogen with pandemic potential, we would be able to detect it rapidly and implement the necessary preventive measures."

Broader Implementation

The initiative at GOSH builds upon earlier trials conducted at Guy's and St Thomas' NHS Trust, where metagenomics was first utilized to test for respiratory infections in adult patients.