Early-onset Sepsis and Antibiotic Exposure in Term Infants: A Nationwide Population-based Study in Norway.

Background: Sepsis is a leading cause of neonatal morbidity and mortality. Clinical suspicion may lead to overuse of antibiotics. The objective of this study was to assess the epidemiology of early-onset sepsis (EOS) and antibiotic exposure during the first week of life in Norwegian term infants.

Methods: This is a nationwide population-based study from the Norwegian Neonatal Network. During the 3-year study period (2009-2011), 20 of Norway's 21 neonatal units prospectively collected data. Among 168,877 live-born (LB) term infants born during the study period, 10,175 (6.0%) infants were hospitalized in the first week of life and included in the study.

Results: There were 91 cases of culture-confirmed EOS (0.54 per 1000 LB) and 1447 cases classified as culture-negative EOS (8.57 per 1000 LB). The majority of culture-confirmed EOS cases were caused by Gram-positives (83/91; 91%), most commonly group B streptococci (0.31 per 1000 LB). Intravenous antibiotics were administered to 3964 infants; 39% of all admissions and 2.3% of all LB term infants. Empiric therapy consisted of an aminoglycoside and either benzylpenicillin or ampicillin in 95% of the cases. The median (interquartile range) treatment duration was 8 (7-10) days for culture-confirmed EOS and 6 (5-7) days for culture-negative EOS. There was 1 EOS-attributable death (group B streptococcal EOS) during the study period.

Conclusions: In this registry-based study, the incidence of culture-confirmed EOS was in line with previous international reports and the mortality was very low. A large proportion of infants without infection were treated with antibiotics. Measures should be taken to spare neonates unnecessary antibiotic treatment.