Sepsis of the preterm neonate Innovative concepts of prevention and early diagnostics

Neonatal sepsis is a leading cause of mortality in the neonatal period worldwide. Preterm infants are particularly susceptible to severe infections. Due to the rapid course, the high mortality and the lack of reliable early markers, empirical antibiotic treatment must often be initiated even when sepsis is only suspected. Therefore, the majority of preterm neonates are subjected to an antibiotic treatment at least once during their stay in the neonatal intensive care unit. Established preventive measures have not significantly reduced the incidence of neonatal sepsis over the past years. An unfavorable intestinal microbiome and immunological specificities of the preterm infant were identified as critical risk factors for neonatal sepsis. Therefore, the postnatal development of the intestinal microbiome and the interplay with the maturing immune system have become a focus for the development of new treatment strategies. Recent studies have fundamentally changed the understanding of the neonatal immune system. The previously assumed immaturity of neonatal immune responses has now been replaced by the concept of specific programming that enables an event-free transition from the intrauterine to the extrauterine world. The alarmins S100A8-A9 play an important role in these processes. They protect the neonate from excessive inflammatory reactions during bacterial colonization without impairing the pathogen defence mechanisms. These findings offer new options as predictive biomarkers and for the prevention of neonatal sepsis.