To determine the incidence, clinical characteristics, and risk factors associated with the first culture-proven episode of sepsis among neonates in a neonatal intensive care unit (NICU).

Level-II NICU in the United Kingdom.

Neonates with their first culture-proven sepsis between January 1, 1996, and December 31, 2000.

Demographic data were obtained from the NICU database and chart review. Sepsis was considered early (EOS; < 72 hours old) or late (LOS; > 72 hours old). Data were also collected on potential risk factors.

Among 14,767 live births, 1,612 (11%) neonates were admitted to the NICU during the study period. Nine hundred eight were screened for sepsis. One hundred twenty-four had at least one positive culture (overall sepsis rate of 8.4 per 1,000 live births [1%] or 77 per 1,000 NICU admissions). Twenty-four neonates had EOS and 100 had LOS. Coagulase-negative staphylococci (CoNS) and group B Streptococcus were the most frequent organisms causing EOS, whereas CoNS and Escherichia coli most frequently caused LOS. Birth before 30 weeks' gestation and birth weight less than 1,500 g were risk factors for sepsis. Resuscitation at birth was the leading risk factor for EOS and respiratory support prior to sepsis, presence of a central or peripheral catheter, and total parenteral nutrition were leading risk factors for LOS.

A strong inverse relationship existed between gestational age of 30 weeks or younger and birth weight of 1,500 g or less and LOS. Resuscitation and indwelling intravenous catheters were also risk factors.