Neonatal sepsis and septic shock: towards the implementation of phenotyping into clinical practice

Neonatal sepsis is a bloodstream infection occurring in newborns up to 28 days of age, classified as early-onset or late-onset depending on the timing of infection. It remains a leading cause of morbidity and mortality among neonates. The complex and poorly understood pathogenesis of neonatal sepsis complicates its diagnosis and treatment. The neonatal population itself is highly heterogeneous, differing significantly from any other age group. This results in variable clinical presentations and the lack of a unified knowledge base, despite ongoing efforts to establish international clinical guidelines. The problem is exacerbated by the absence of universal definitions and criteria for neonatal sepsis and septic shock, hindering data standardization at the global level. The heterogeneity of sepsis presents an additional challenge, driven by differences in gestational age, onset timing, and sources of infection. Phenotyping emerges as a promising approach, enabling the identification of subgroups of patients with shared pathophysiological characteristics, prognoses, and treatment responses. Sepsis phenotyping is widely studied in adults and pediatric populations, with an increasing number of publications on its clinical applications. However, in Russian scientific databases, data on phenotyping in pediatrics remain scarce, and studies focused on neonates are nearly absent. This underscores the urgent need for further research to enhance the diagnosis and treatment of neonatal sepsis.