Neonatal Sepsis from 2014-2024: The Resurgence of Gram-Negative Rods.

OBJECTIVES To evaluate the incidence, pathogens, clinical characteristics, and outcomes of neonatal sepsis at a single, level IV, neonatal intensive care unit (NICU) from 2014-2024, and compare results with historical, institutional data.

STUDY DESIGN Retrospective cohort study of infants with a documented blood stream infection from 2014-2024. Episodes were documented prospectively, and data collected retrospectively and assessed via univariate and multi-regression analyses. Data were compared between epoch 1 (2004-2013) and 2 (2014-2024) and trends since 1928 analyzed.

RESULTS 250 sepsis episodes occurred in 233 infants from 2014-2024. Early-onset sepsis (EOS) attributed to gram-negative organisms increased in epoch 2, as did identification of historically uncommon organisms associated with EOS. Escherichia coli (E. coli)-related EOS increased between epochs in late preterm and term neonates (13% to 36%;173% increase) and in very low birth weight infants (58% to 64%; 10% increase). Although a lower rate of late-onset sepsis (LOS) was observed in epoch 2, mean gestational age was lower and disease severity greater. Forty percent of LOS episodes were attributed to gram-negative bacteria, with an increase noted from 32% of episodes (2014-2019) to 50% (2020-2024). LOS-related mortality increased in epoch 2 (11% to 25%;127% increase), with overall sepsis-related mortality increasing steadily over 3 decades. Predictors of sepsis-related mortality included lower birth weight, need for pressors, concurrent necrotizing enterocolitis, and thrombocytopenia.

CONCLUSIONS Pathogen distribution for EOS and LOS revealed a sustained increase in gram-negative organisms, predominantly E. coli. This trend coupled with decreasing gestational age and increasing baseline illness severity likely contributed to increased sepsis-related mortality.