Late-onset bloodstream infections in hospitalized term infants.

Background: The epidemiology and incidence of late-onset blood stream infections (BSIs) in premature infants have been described, but studies describing late-onset BSI in term infants are sparse. We sought to describe the pathogens, incidence, risk factors and mortality of late-onset BSI in hospitalized term infants.

Methods: A cohort study was conducted of infants ≥37 weeks gestational age and ≤120 days of age discharged from Pediatrix Medical Group neonatal intensive care units from 1997 to 2010. We examined all cultures obtained from day of life 4-120 and used multivariable regression to assess risk factors for late-onset BSI.

Results: We found a total of 206,019 infants cared for between day of life 4 and 120, and the incidence of late-onset BSI was 2.7/1000 admissions. We identified Gram-positive organisms in 64% of the cultures and Gram-negative organisms in 26%. We found a decreased risk of late-onset BSI in infants with the following characteristics: small for gestational age, delivery by Cesarean, antenatal antibiotic use and discharged in the later years of the study. Late-onset BSI increased the risk of death after controlling for confounders [odds ratio 8.43 (95% confidence interval 4.42-16.07)].

Conclusion: Our data highlight the importance of late-onset BSI in hospitalized term infants. We identified Gram-positive organisms as the most common pathogen, and late-onset BSI was an independent risk factor for death.