Neonatal sepsis workups in infants >= 2000 grams at birth: A population-based study

Background. Few data are available on the outcome of neonatal sepsis evalua tions in an era when intrapartum antibiotic therapy is common. Methods. We identified all newborns weighing greater than or equal to 2000 g at birth who were ever evaluated for suspected bacterial infection at 6 K aiser Permanente hospitals between October 1995 and November 1996, reviewed their records and laboratory data, and tracked them to 1 week after discha rge. We analyzed the relationship between key predictors and the presence o f neonatal bacterial infection. Results. Among 18 299 newborns greater than or equal to 2000 g without majo r congenital anomalies, 2785 (15.2%) were evaluated for sepsis with a compl ete blood count and/or blood culture. A total of 62 (2.2%) met criteria for proven, probable, or possible bacterial infection: 22 (.8%) had positive c ultures and 40 (1.4%) had clinical evidence of bacterial infection. We trac ked all but 10 infants (.4%) to 7 days postdischarge. There were 67 rehospi talizations (2.4%; 2 for group B streptococcus bacteremia). Among 1568 infa nts who did not receive intrapartum antibiotics, initial asymptomatic statu s was associated with decreased risk of infection (adjusted odds ratio [AOR ]: .26; 95% confidence interval [CI]: .11-.63), while chorioamnionitis (AOR : 2.40; 95% CI: 1.15-5.00), low absolute neutrophil count (AOR: 2.84; 95% C I: 1.50-5.38), and meconium-stained amniotic fluid (AOR: 2.23; 95% CI: 1.18 -4.21) were associated with increased risk. Results were similar among 1217 infants who were treated, except that maternal chorioamnionitis was not si gnificantly associated with neonatal infection. Conclusions. The risk of bacterial infection in asymptomatic newborns is lo w. Evidence-based observation and treatment protocols could be defined base d on a limited set of predictors: maternal fever, chorioamnionitis, initial neonatal examination, and absolute neutrophil count. Many missed opportuni ties for treating mothers and infants exist.