Epidemiology of neonatal sepsis in South Korea.

BACKGROUND Neonatal sepsis is a severe clinical syndrome characterized by systemic signs of infection, shock and system organ failure; diagnosis is confirmed on positive culture from a normally sterile site(s). There are few reports comparing incidence, mortality, and risk factors between clinically diagnosed sepsis and that confirmed by culture. METHODS All infants diagnosed with early- (within first 72 h after birth) or late-onset (72 h-4 weeks after birth) neonatal sepsis between 1997 and 1999 from four neonatal centers in South Korea, were investigated. RESULTS The estimated incidence rate of neonatal sepsis during the 3 years was 30.5 per 1000 live births for clinical sepsis and 6.1 per 1000 live births for sepsis with positive culture, with case-fatality rates of 4.7% and 2.2%, respectively. When only early-onset sepsis was considered, the incidence and fatality rates were 25.1 per 1000 live births and 6.1% for clinical sepsis, and 4.3 per 1000 live births and 2.5% for culture-confirmed sepsis, respectively. For the 179 patients (185 causative organisms) of proven sepsis, Staphylococcus spp. including S. aureus were the most frequent isolates. In early-onset clinical sepsis, having very low birthweight (<or=1500 g), a low Apgar score at 5 min (<or=7), and being male were related to higher rates of case-fatality (relative risk: 11.3, 6.8 and 2.5, respectively). CONCLUSIONS Clinical sepsis was more common than culture-confirmed sepsis and had a higher case-fatality rate. It seems prudent to take rapid and decisive steps toward better management of the high-risk group whether the sepsis is clinically diagnosed or culture confirmed.