Incidence, clinical characteristics and attributable mortality of persistent bloodstream infection in the neonatal intensive care unit

Background: An atypical pattern of neonatal sepsis, characterized by persistent positive blood culture despite effective antimicrobial therapy, has been correlated with adverse outcomes. However, previous studies focused only on coagulate-negative staphylococcus infection. Methods: All episodes of persistent bloodstream infection (BSI), defined as 3 or more consecutive positive blood cultures with the same bacterial species, at least two of them 48 hours apart, during a single sepsis episode, were enrolled over an 8-year period in a tertiary level neonatal intensive care unit. These cases were compared with all non-persistent BSI during the same period. Results: We identified 81 episodes of persistent BSI (8.5% of all neonatal late-onset sepsis) in 74 infants, caused by gram-positive pathogens (n=38, 46.9%), gram-negative pathogens (n=21, 25.9%), fungus (n=20, 24.7%) and polymicrobial bacteremia (n=2, 2.5%). Persistent BSI does not differ from non-persistent BSI in most clinical characteristics and patient demographics, but tends to have a prolonged septic course, longer duration of feeding intolerance and more frequent requirement of blood transfusions. No difference was observed for death attributable to infection (9.8% vs. 6.5%), but neonates with persistent BSI had significantly higher rates of infectious complications (29.6% vs. 9.2%, P < 0.001), death from all causes (21.6% vs. 11.7%, P = 0.025), and duration of hospitalization among survivors [median (interquartile range): 80.0 (52.5-117.5) vs. 64.0 (40.0-96.0) days, P = 0.005] than those without persistent BSI. Conclusions: Although persistent BSI does not contribute directly to increased mortality, the associated morbidities, infectious complications and prolonged septic courses highlight the importance of aggressive treatment to optimize outcomes.