Neonatal sepsis: Epidemiology and comparison between preterm and term newborns

Neonatal sepsis is a severe clinical syndrome that continues to be a common and significant health care burden. Knowledge of the local epidemiology allows for a better empirical treatment and improves morbidity and mortality. The aim of this study was to determine the prevalence, epidemiology, and etiology of blood culture-proven sepsis in neonates and to determine whether there are differences between preterm and term newborns.

A retrospective study was carried out in a tertiary hospital in Madrid, Spain, during 2021, including 1443 patients at risk of developing sepsis.

The majority of sepsis episodes occurred in preterm newborns (64.81%) and most of them were very low birth weight infants (74.29%). Late-onset sepsis represented 94.92% of all the episodes reported with an incidence of 11.4 (95% CI 8.8-14.8) per 1000 live newborns. Early onset sepsis incidence was 0.6 (95% CI 0.2-1.8) per 1000 live newborns. Coagulase-negative staphylococci took the first place as causative agents of sepsis (66.10%), causing in all the episodes late onset catheter-related bloodstream infection. When the newborns who developed sepsis were compared with those who did not developed sepsis, the presence of venous/arterial access device was significantly associated with sepsis in both preterm (odds ratio (OR) 8.12, 95% CI 0.47-141.40) and term newborns (OR 16.58, 95% CI 1.00-275.20). Recent surgery was nevertheless the main risk factor in term newborns (OR 45.29, 95% CI 13.70-149.70). Among those patients who developed sepsis, no differences between preterm and term newborns were found regarding time onset, mechanism of transmission, etiological agents, and mortality. A 100% of the preterm and 42.11% of the term newborns presented two or more risk factors. The mortality rate observed here has been 1.85% (95% CI 0.33-9.77%).

The main risk factors for sepsis were venous/arterial access device (for both preterm and term newborns) and recent surgery (term newborns). Prematurity and being a catheter carrier were strongly associated with late-onset neonatal sepsis, mainly due to coagulase-negative staphylococci. The mortality rate was lower than that observed in other high-income countries.