A Translational Preterm Piglet Model For Neonatal Sepsis.

Preterm infants are particularly vulnerable to bacterial infections that may rapidly progress to life-threatening sepsis, a state of excessive inflammation and organ dysfunction. To investigate disease mechanisms and advance therapeutic development, robust translational animal models that replicate the complex pathophysiology and clinical presentation of neonatal sepsis are critically needed. This protocol presents a clinically relevant preterm piglet model of neonatal sepsis, induced via intra-arterial infusion of live Staphylococcus epidermidis shortly after birth or on postnatal day three. Piglets are delivered at 90% gestation by cesarean section and cared for under neonatal intensive care conditions. These include temperature- and oxygen-controlled incubators and an indwelling umbilical arterial catheter, which enables delivery of parenteral nutrition and serial blood sampling. Following infection with S. epidermidis, piglets are monitored for 24-48 h. The incidence and severity of sepsis can be modulated by the dose of bacteria and the supply of parenteral glucose. Higher provision of parenteral glucose accelerates pro-inflammatory immune responses, leading to clinical deterioration. Lethal sepsis and humane endpoints are defined by arterial blood gas parameters (pH ≤ 7.1) combined with clinical signs of hemodynamic compromise such as lethargy, skin discoloration, and tachypnea. This model provides a unique platform to explore how energy metabolism and immunomodulatory interventions affect bacterial clearance, systemic inflammation, and tissue injury during neonatal infection. It holds significant potential to inform clinical strategies for the prevention and treatment of neonatal sepsis.