Neonatal enterococcal sepsis: case-control study and description of an outbreak

An increased incidence of neonatal sepsis caused by Group D streptococci, specifically enterococci (GDE), during a recent 6-month period prompted a 5-year review of enterococcal sepsis in our neonatal intensive care unit. Sixteen episodes occurred in 14 babies. GDE accounted for 8 of 19 (42%) episodes of neonatal bacteremia during the epidemic period vs. only 8 of 159 (5%) episodes during the remaining 4.5 years (endemic period) (P less than 0.001). Blood isolates were all identified as Streptococcus faecalis. A combination of three strain-typing methods successfully distinguished the epidemic organisms from endemic nursery strains of GDE and from "background" GDE flora in the hospital. Nursery isolates were all susceptible to ampicillin, intermediate or resistant to the aminoglycosides and variably resistant to the newer cephalosporins. There were no differences in antibiotic susceptibilities of the GDE or in characteristics of the patients that were unique to the epidemic. Neonates with GDE sepsis had a mean birth weight of 913 g, a mean gestational age of 27 weeks and a mean age of onset of sepsis of 8.5 weeks. Twenty-five controls, matched for birth weight and admission date, were identified. Significant differences (P less than 0.05) between cases and controls included: use of a nonumbilical central line (71 vs. 32%); days central line in place (26.5 vs. 6.5 days); and bowel resection (29 vs. 4%). This is the first reported outbreak of S. faecalis sepsis in neonates. GDE are important nosocomial pathogens that must be considered in late onset neonatal sepsis.