Abstract
Preterm infants are highly susceptible to bacterial infections and inflammatory diseases. These vulnerabilities arise from disruptions in gut microbiome structure and function, immune system immaturity, and underdeveloped organ systems. In this review, we explore the role of the gut microbiome in neonatal health. With a specific focus on preterm infants, we outline how microbiome disruption contributes to negative clinical outcomes. First, we provide an overview of infant gut microbiome development, highlighting key factors that influence its trajectory. Next, we examine the interplay between the infant gut microbiome and the development of systemic and intestinal immune systems, with emphasis on how microbiome perturbations related to preterm birth alter host-microbiome interactions and the overall immune landscape. We then discuss the role of altered gut composition in disease states common to preterm infants, such as sepsis, bacterial infections, and necrotizing enterocolitis. Finally, we discuss current and future diagnostics and treatments and offer our perspective on future research to untangle the host-microbiome interface in early life.