Long-term trends in the epidemiology of neonatal sepsis and antibiotic susceptibility of causative agents

Background: In an era with increased maternal antibiotic use, patterns in early- and late-onset sepsis and antibiotic susceptibility may have changed. Objectives: To identify longitudinal trends in causative microorganisms for neonatal sepsis and analyze antibiotic susceptibility of all blood isolates of infants with sepsis. Methods: Early- and late-onset sepsis cases from 29 years (1978-2006) were studied retrospectively, in five clusters of 5 years (period I-V) and one cluster of 4 years (period VI), including antibiotic susceptibility profiles of blood isolates during the years 1999-2006. Results: The incidence of early-onset sepsis decreased (p <0.01) from 4% during period I (1978-1982) to 1.2% during period VI (2003-2006). 78% of the infants with group B streptococcal (GBS) sepsis were premature during period I, compared to 47% during period VI (p <0.05). The incidence of early-onset Gram-negative infections remained low during all periods. The incidence of late-onset sepsis, predominantly caused by coagulase-negative staphylococci (CONS) and Staphylococcus aureus, increased since period III from 7.1 to 13.9% in period VI (p <0.01). Infections due to fungi or yeasts were rare (incidence