Premature birth can leave newborns vulnerable to serious complications, including necrotizing enterocolitis, a rapidly developing condition that can be difficult to identify early. New research suggests that changes in the gut microbiome may provide warning signals before noticeable symptoms appear.

By examining bacteria, bacteriophages, and antibiotic-resistance genes, scientists are gaining a more detailed view of microbial changes linked with this condition.

A More Complex Microbial Picture

For years, research into necrotizing enterocolitis has focused heavily on bacteria within the intestinal microbiome. The new findings suggest that this approach may overlook another important component: bacteriophages, viruses that infect bacteria.

Bacteriophages, often shortened to phages, do not primarily target human cells. Instead, they interact with bacteria and can insert genetic material into bacterial genomes. Some of these genetic elements can influence bacterial behavior, including traits associated with antibiotic resistance and survival.

The research team examined this largely overlooked viral component, known as the gut prophageome. The analysis showed that changes in phage populations and their interactions with bacteria could provide useful signals before signs of illness became apparent.

What the Researchers Examined

The investigation combined metagenomic and metatranscriptomic techniques with machine-learning analysis. These approaches allowed researchers to examine genetic material present in stool samples and determine how microbial communities changed over time.

The dataset included 1,825 longitudinal stool samples from 43 premature babies who later developed necrotizing enterocolitis and 86 matched comparison participants. The babies were matched according to gestational age and birth weight, helping researchers account for important differences associated with premature birth. Samples were collected across three hospitals.

Early-Onset Cases Showed Viral-Bacterial Signals

The research identified a particularly important pattern in early-onset necrotizing enterocolitis. Phage-bacterial interaction signatures provided a predictive signal, with the computational model reaching approximately 75% accuracy and 81% sensitivity in the study dataset.

Additional genetic analysis showed increased phage DNA alongside relatively low phage gene activity. The researchers interpreted this pattern as consistent with a lysogenic state, in which phage genetic material remains within bacterial populations rather than immediately producing new virus particles.

Some of the identified phages also carried metabolic genes that could potentially influence the ability of bacterial populations to persist. These findings suggest that the relationship between bacteria and their viruses may be more biologically important than previously recognized.

Later-Onset Cases Followed a Different Pattern

The researchers also found that later-onset necrotizing enterocolitis appeared to have a different microbial signature. Instead of phage-bacterial interactions providing the strongest predictive information, antibacterial resistance genes were more informative.

The model identified late-onset cases with approximately 83% accuracy. The study linked the accumulation of resistance genes with repeated antibiotic exposure during prolonged stays in neonatal intensive care settings, although the findings do not establish that antibiotic exposure alone causes the condition.

Expert Insight

Barbara Warner, MD, co-corresponding author of the study, is the F. Sessions Cole Chair in Newborn Medicine and director of the Division of Newborn Medicine at Washington University School of Medicine. She described the clinical importance of improving early recognition. “When dealing with a disease as sudden and devastating as necrotizing enterocolitis, every day counts.”

Why Phages Could Matter

The findings highlight an increasingly important concept in microbiome science: bacteria do not exist independently. Their behavior can be influenced by viruses, genetic exchanges, environmental conditions and exposure to medications.

Phages can move genetic material between bacterial populations, potentially affecting characteristics such as resistance to antimicrobial medicines. This means that a microbiome assessment based solely on bacterial species may miss important biological information.

The study's authors propose that the prophageome could eventually become part of a broader framework for identifying risk before clinical deterioration. However, the current results should not be interpreted as a ready-to-use diagnostic test. The predictive models were developed from a specific research cohort, and further validation across larger and more diverse populations will be necessary.

What Comes Next

The research opens several avenues for future investigation. Larger studies could determine whether the same microbial signatures appear consistently in neonatal intensive care units beyond the three hospitals included in the analysis. Researchers will also need to establish whether particular phage-bacterial interactions directly contribute to disease development or primarily serve as early biological indicators.

Research published in Gut indicates that the gut microbiome contains signals associated with necrotizing enterocolitis before clinical symptoms emerge. The results are promising for future early-warning systems, but additional research is required before these microbial signatures can be applied routinely in clinical care.