The study, led by R.J. Graf, A. Edwards, M.A. Crowley and colleagues, focuses on “time to blood culture positivity,” the interval between collecting a blood sample and detecting microbial growth in the laboratory. Blood cultures remain a central tool for diagnosing sepsis, including late-onset sepsis in newborns. When bacteria or fungi are present, they may multiply in the culture bottle and trigger an automated signal. If no growth is detected after a defined period, clinicians must decide whether antibiotics can safely be stopped, even though a negative result cannot provide absolute certainty.

That decision is especially consequential in the NICU. Newborns, particularly those born very prematurely or with very low birth weight, have immature immune systems and limited physiological reserves. Infection may present with nonspecific changes in breathing, temperature, feeding, heart rate or blood pressure. Because the consequences of missing sepsis can be catastrophic, clinicians often begin broad-spectrum antibiotics while awaiting culture results. Yet many infants who receive this emergency treatment ultimately do not have a confirmed infection.

The resulting exposure is not harmless. Antibiotics can disrupt the developing intestinal microbiome, the complex community of microorganisms that influences digestion, immune development and resistance to invading pathogens. In premature infants, alterations in this ecosystem have been associated with concerns including intestinal inflammation and vulnerability to antimicrobial-resistant organisms. Prolonged or repeated treatment can also expose infants to medication toxicity and contribute to the wider public-health problem of antibiotic resistance. The clinical challenge is therefore not simply to use antibiotics quickly, but to use them for the shortest safe duration.

A blood culture’s time to positivity is influenced by several technical and biological factors. The number of organisms in the original sample, the volume of blood collected, the type of pathogen and whether antibiotics were given before the sample was obtained can all affect detection. In neonates, the small amount of blood that can safely be drawn creates an additional limitation. A culture containing only a tiny number of microorganisms may take longer to signal than one with a larger initial burden, while prior antimicrobial exposure may suppress growth altogether.

The study’s focus reflects a broader effort to make antibiotic decisions more precise rather than relying on a fixed waiting period for every infant. If the great majority of clinically meaningful bloodstream infections become detectable within a defined window, then continuing antibiotics beyond that point may provide little additional protection for infants who remain stable and whose cultures show no growth. Conversely, if certain organisms or clinical situations regularly require more time, an overly aggressive stopping rule could create unacceptable risk. The value of a time-based approach depends on how accurately it distinguishes these different scenarios.

This is why culture timing cannot be interpreted in isolation. Neonatologists must combine laboratory results with the infant’s clinical condition, the quality of the blood sample, inflammatory markers, the likelihood of infection before testing and the presence of other possible sources of illness. A negative culture does not automatically exclude infection, particularly when the sample volume is inadequate or antibiotics were administered first. The study’s central question is therefore not whether a clock can replace clinical judgment, but whether better evidence about that clock can support safer, more consistent decisions.

The work arrives at a moment when hospitals are increasingly adopting antimicrobial stewardship programs designed specifically for newborn care. These programs seek to reduce unnecessary antibiotic starts and shorten treatment courses without increasing missed infections or complications. In practice, the findings from research on culture positivity could help NICUs develop protocols that define when antibiotics should be reassessed, what additional evidence should be considered and which infants require prolonged observation. Such protocols could also reduce variation between clinicians and institutions, where local habits sometimes determine treatment duration as much as microbiological evidence.

For families, the issue is often experienced as a confusing trade-off: antibiotics may be started urgently, but stopping them can feel risky when a newborn remains medically fragile. Clearer data about when cultures become positive could make those conversations more transparent. It could also encourage hospitals to improve the fundamentals of culture collection, including obtaining an adequate blood volume before treatment whenever clinically possible, because laboratory timing is meaningful only when the initial sample is capable of detecting infection.

By revisiting the timing of blood culture positivity, Graf, Edwards, Crowley and their colleagues place a familiar diagnostic test at the center of a pressing neonatal-care question. The ultimate goal is not simply fewer antibiotic doses, but a more accurate separation between infants who need immediate and sustained treatment and those for whom early therapy can be safely discontinued. In the NICU, where both infection and over-treatment carry real dangers, refining that distinction could turn a laboratory result into a powerful tool for protecting newborn health.

Subject of Research: Time to blood culture positivity and reducing antibiotic exposure in the neonatal intensive care unit (NICU)

Article Title: Revisiting time to blood culture positivity: can we decrease antibiotic exposure in the NICU?

Article References: Graf, R.J., Edwards, A., Crowley, M.A. et al. “Revisiting time to blood culture positivity: can we decrease antibiotic exposure in the NICU?” Journal of Perinatology (2026). https://doi.org/10.1038/s41372-026-02838-z

Image Credits: AI Generated

DOI: 10.1038/s41372-026-02838-z

Keywords: neonatal intensive care, blood culture, time to positivity, neonatal sepsis, antibiotic stewardship, premature infants, antimicrobial exposure, microbiology

VLBW infants, defined as those weighing less than 1500 grams at birth, are especially susceptible to sepsis due to their underdeveloped immune systems and frequent exposure to invasive procedures in neonatal intensive care units (NICUs). Rapid and accurate diagnosis is crucial since delays in treatment can lead to irreversible organ damage or death. Traditional diagnostic methods, including blood cultures, are notoriously slow and sometimes insensitive, prompting the search for quicker, more reliable diagnostic tools.

Biomarkers such as C-reactive protein (CRP), procalcitonin (PCT), and various cytokines have been deeply investigated for their ability to serve as early warning signals for infection. These biomarkers offer not only faster results than cultures but also quantitative data that can potentially help stratify patients by risk and guide therapeutic decisions. Wang and Mukhopadhyay’s research delves into the practical application—or rather the underutilization—of these markers in real-world NICU settings.

The study reveals multifaceted barriers that hinder the seamless integration of biomarker testing into neonatal sepsis protocols. These include concerns over cost-effectiveness, variability in biomarker performance depending on individual patient factors, and a lack of standardized guidelines. While biomarkers confer undeniable diagnostic benefit, many clinicians remain hesitant, either due to unfamiliarity with interpreting biomarker trends or skepticism regarding their incremental advantage over existing clinical judgment.

Technological advances have made point-of-care biomarker assays possible, enabling rapid bedside testing that could dramatically reduce diagnostic turnaround time. Despite this, the diffusion of such innovations into routine NICU workflow is sluggish. Wang and Mukhopadhyay highlight the discrepancy: clinical laboratories may offer these tests, but integration into clinical pathways, electronic health record prompts, and decision-support systems is lagging, blunting their direct impact on patient care.

Furthermore, the researchers underscore the complexity of neonatal immune responses, where biomarker levels can fluctuate due to factors unrelated to infection, such as stress from mechanical ventilation or postnatal adaptation processes. This biological noise complicates interpretation and demands more refined algorithms that combine biomarker data with clinical parameters to improve specificity and sensitivity.

Wang and Mukhopadhyay also discuss the need for prospective, multicenter clinical trials to validate biomarker-guided treatment protocols. Such trials could clarify optimal threshold values, timing of measurements, and combinations of biomarkers to be used. These efforts are essential to move from promising research findings into firm, evidence-based clinical guidelines that clinicians can rely on confidently.

An intriguing element in the review is the exploration of novel biomarkers emerging from cutting-edge technologies such as proteomics and metabolomics. These discovery platforms promise to identify unique molecular signatures of infection that might outperform established markers or provide insights into sepsis pathophysiology at unprecedented depth. However, translating these discoveries into usable bedside tests faces hurdles in terms of regulatory approval, cost, and complexity.

The authors importantly draw attention to the ethical dimensions of biomarker deployment. In VLBW infants, overtreatment with antibiotics due to false-positive sepsis evaluations can promote antibiotic resistance, disrupt microbiomes, and have long-term developmental consequences. Biomarker assays that accurately rule out infection, therefore, have enormous potential to reduce unnecessary interventions and improve long-term outcomes. Yet this requires high confidence in negative predictive value, which current biomarkers have not universally achieved.

This implementation gap highlighted by the study reflects a broader challenge in neonatology: how to balance rapid access to novel diagnostic tools with the cautious rigor demanded when treating an exceptionally fragile population. Wang and Mukhopadhyay argue convincingly that overcoming this gap will necessitate integrated efforts—combining basic science, clinical research, health economics, and implementation science.

Notably, the paper calls for enhanced education and training programs aimed at NICU teams, emphasizing biomarker interpretation and the nuances of neonatal immune responses. It also suggests that collaboration between diagnostic manufacturers, clinical researchers, and policy makers could drive the standardization and acceptance of biomarker-based protocols.

This emerging paradigm where biomarkers function as cornerstones of neonatal sepsis management holds the potential to shift clinical outcomes dramatically. But without targeted strategies to embed these tools effectively into practice, the gap between promise and reality may widen. Wang and Mukhopadhyay make a compelling case that closing this gap must be a priority for neonatology in the coming decade.

In integrating biomarker science with clinical workflows, the ultimate goal is personalized medicine tailored to the unique vulnerabilities of VLBW infants. This means not just detecting sepsis accurately and promptly but also stratifying patients for appropriate therapeutic intensity and monitoring prognostic trajectories. Achieving this vision will require addressing the technological, educational, and organizational barriers this study meticulously outlines.

In conclusion, the findings presented by Wang and Mukhopadhyay underscore a crucial inflection point in neonatal care. Biomarkers stand ready to revolutionize the evaluation of sepsis in VLBW infants, but systemic inertia and knowledge gaps threaten to delay this progress. Bridging this implementation gap calls for concerted action that spans innovation, evidence generation, and clinician engagement to realize the full promise of biomarker-guided neonatal care.

Subject of Research:
Utility of biomarkers in the clinical evaluation of sepsis in very low birth weight (VLBW) infants and challenges in their implementation.

Article Title:
Utility of biomarkers in VLBW sepsis evaluations: the implementation gap

Article References:
Wang, X., Mukhopadhyay, S. Utility of biomarkers in VLBW sepsis evaluations: the implementation gap. Pediatr Res (2026). https://doi.org/10.1038/s41390-026-05043-y

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41390-026-05043-y