Preterm infants demonstrate a uniquely vulnerable pattern of early gut colonization shaped by physiological immaturity, intensive care interventions, and restricted microbial exposure. These early deviations from natural colonization trajectories significantly influence immune system maturation, metabolic regulation, and the infant’s ability to adapt to extra uterine life. Evidence shows that dysbiosis in preterm newborns—characterized by low microbial diversity and the predominance of opportunistic pathogens—correlates with higher risks of necrotizing enterocolitis, late onset sepsis, inflammatory dysregulation, and feeding intolerance. This article provides an expanded analysis of early life microbial development in preterm infants, examines its mechanistic links to immune and clinical outcomes, and evaluates emerging therapeutic and diagnostic strategies aimed at optimizing microbiota formation and improving neonatal resilience.

Preterm infants, intestinal microbiota, immune development

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