Postconception Age and Other Risk Factors Associated with Mortality Following Gram-negative Rod Bacteremia

Abstract
BACKGROUND: Neonatal nosocomial Gram-negative rod bacteremia (GNR-b) is considered ominous. DESIGN: Multi-center cohort study of premature infants (N=6172) who had a blood culture after day of life 3 and whose birthweight was 1250 g. RESULTS: A total of 437 neonates developed GNR-b; most commonly with Klebsiella (122/437; 28%), Enterobacter (97/437; 22%), Escherichia coli (90/437; 21%), Pseudomonas (63/437; 14%), and Serratia (49/437; 11%). Neonates infected with Pseudomonas were more likely to die (21/63; 33%) than infants infected with other GNR (50/374; 13%). In multivariable logistic regression, infection with Pseudomonas, mechanical ventilation, and race were associated with subsequent mortality. Postconception age (PCA) was most strongly associated with mortality. Using neonates with >34 weeks PCA at the time of the first blood culture as the reference category, mortality was higher in neonates Pseudomonas rather than enteric GNR. Race, the need for mechanical ventilation, and younger PCA when the blood culture was obtained were also strongly associated with mortality.