561 - Can Microbiome Signatures and Inflammatory Markers Distinguish Culture-Negative Neonatal Sepsis?

Publication Number: 561.4183

Morcos Hanna, Texas Children's Hospital, Houston, TX, United States; Shixia Huang, Baylor College of Medicine, Houston, TX, United States; Matthew Ross, Baylor College of Medicine, Houston, TX, United States; Anaid Reyes, Baylor College of Medicine, Houston, TX, United States; Dimuthu Perera, Baylor College of Medicine, Houston, TX, United States; Anil Surathu, Baylor College of Medicine, Gaithersburg, MD, United States; Sara Joan Javornik Cregeen, Baylor College of Medicine, Houston, TX, United States; Joseph Hagan, Baylor College of Medicine, Houston, TX, United States; Mohan Pammi, Baylor College of Medicine, Houston, TX, United States

Background: The term ‘culture-negative sepsis’ refers to neonates who present with symptoms of sepsis and are treated with antibiotics, despite having negative blood cultures. The etiology of culture-negative sepsis remains unclear and may involve undetectable viruses, fungi, or other microbes, poor sampling techniques (e.g., insufficient blood volume), or non-infectious inflammatory causes. Antibiotic overuse is common in these cases.

Objective: The objective of this study was to determine whether preterm neonates with culture-negative sepsis exhibit altered microbial diversity and composition, as well as elevated pro-inflammatory cytokine and chemokine profiles, compared to asymptomatic controls.

Design/Methods: In this prospective study, we enrolled 50 preterm neonates: 19 with culture-positive sepsis, 21 with culture-negative sepsis, and 10 asymptomatic controls. Blood, stool, and skin swabs were collected at the time of sepsis evaluation or enrollment for controls. Metagenomic sequencing was used to assess the microbiome composition of bacterial, viral, and fungal components across samples. Cytokine profiles were evaluated using a Human Cytokine/Chemokine Premixed 65-plex kit to assess immune and inflammatory responses. Clinical metadata, including demographic information and patient outcomes, were also collected.

Results: Microbiome analysis of stool, skin, and blood samples did not reveal statistically significant differences in microbial diversity or composition between neonates with culture-negative sepsis and controls (Figure 1). Virome analysis identified 24 viruses on the skin, but the distribution was not statistically different across the three groups. Bacterial DNA was detected in the blood of all groups via 16S sequencing, with no significant differences observed. While cytokine and chemokine levels were elevated in neonates with culture-positive sepsis, there were no significant differences between those with culture-negative sepsis and controls (Figure 2). However, analysis of clinical data revealed a higher incidence of bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), and prolonged hospital stays in the culture-negative sepsis group compared to controls.

Conclusion(s): This pilot study suggests that neonates with culture-negative sepsis do not exhibit significant differences in microbiome diversity, composition, or inflammatory markers compared to asymptomatic controls. However, these infants demonstrated higher rates of BPD, ROP, and extended hospitalization, highlighting potential differences in outcomes despite the absence of detectable infection.

Figure 1. Heatmap of microbiome analysis of all subject samples


Figure 2. A comparison of serum systemic inflammatory markers among participating subjects from all three groups