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 <0.3%). The majority of CONS blood isolates were oxacillin-resistant, but vancomycin-susceptible. 95% of CONS blood isolates were susceptible for first-generation cephalosporins. Amoxicillin/clavulanic acid-resistant Escherichia coli were infrequent causes of infection.

CONCLUSIONS

The incidence of early-onset sepsis mainly caused by GBS decreased. In contrast, the incidence of late-onset sepsis, predominantly caused by CONS, increased significantly. The incidence of fungal and yeast infections remained low. The majority of CONS blood isolates were susceptible for first-generation cephalosporins.