Culture-proven neonatal sepsis in preterm infants in a neonatal intensive care unit over a 7 year period: coagulase-negative Staphylococcus as the predominant pathogen

Abstract

Background: The aim of this study was to determine the causative agents in early, late- and very late-onset sepsis in preterm infants. The demographic features, risk factors, clinical and laboratory findings in sepsis types were also defined.

Methods: A total of 151 preterm infants with culture-proven neonatal sepsis were enrolled in this prospective study. The infants were classified into three groups with regard to the onset of sepsis: early onset sepsis (EOS), late-onset sepsis (LOS) and very late-onset sepsis (VLOS). A sepsis screen including whole blood count, blood smear, infection markers and cultures was performed before initiating antibiotic therapy.

Results: EOS, LOS and VLOS groups consisted of 23, 86 and 42 infants, respectively. Coagulase-negative staphylococci (CONS) was the most common organism in all sepsis groups. The main factors associated with EOS included presence of premature rupture of membranes, antibiotic use in pregnancy and choriamnionitis. Previous antibiotic use was the main factor associated with LOS, while low birthweight was the main factor in infants with VLOS. Although mortality rate due to Gram-negative bacteria and fungi was higher, CONS was an important cause of mortality in infants with LOS and VLOS.

Conclusions: CONS was found to be the most common causative organism in three sepsis types in preterm neonates. Although the mortality rate due to CONS was lower in EOS, it was an important cause of mortality in LOS and VLOS. CONS seems to be the main pathogen in neonatal sepsis in developing countries, as in developed countries.

Keywords: coagulase-negative Staphylococcus; early onset sepsis; late-onset sepsis; neonatal sepsis; preterm infant.