Epidemiology and risk factors for early onset sepsis among very-low-birthweight infants.

OBJECTIVE: The purpose of this study was to determine the incidence, causative pathogens, and risk factors for early onset sepsis (EOS) among very-low-birthweight (VLBW) infants.

STUDY DESIGN: This was a population based observational study. Data were prospectively collected by the Israel Neonatal Network between 1995 and 2005. Multivariable analyses identified independent risk factors for EOS.

RESULTS: EOS developed in 383 of 15,839 infants (2.42%). Fifty-five percent of pathogens isolated were gram-negative bacteria. Lack of prenatal care (odds ratio [OR], 1.94; 95% confidence interval [CI], 1.32-2.86), delivery room resuscitation (OR, 2.49; 95% CI, 1.91-3.24), membrane rupture > 24 hours without amnionitis (OR, 2.10; 95% CI, 1.53-2.88), amnionitis with membrane rupture < 24 hours (OR, 4.28; 95% CI, 2.97-6.16), and amnionitis with membrane rupture >or= 24 hours (OR, 8.15; 95% CI, 5.98-11.10) were associated with EOS, but not antenatal steroids or gestational age.

CONCLUSION: EOS was caused mainly by gram-negative bacteria. Prolonged rupture of membranes and amnionitis have an additive effect on EOS with an above 8-fold excess risk when both were present.