AIM: To compare the frequency of elevated concentrations of inflammation-related proteins in the blood of infants born before the 28th week of gestation who had documented bacteraemia and those who had presumed (antibiotic-treated but culture-negative) bacteraemia to those who had neither.

METHODS: The subjects of this study are the 868 infants born at 14 institutions for whom information about protein measurements on at least two of the three protocol days (days 1, 7, and 14) was available and who did not have Bell stage 3 necrotizing enterocolitis or isolated bowel perforation, which were strongly associated with bacteraemia in this sample.

RESULTS: Newborns with presumed early (week 1) bacteraemia had elevated concentrations of only a few inflammation-related proteins, while those who had presumed late (weeks 2-4) bacteraemia did not have any elevations. In contrast, newborns who had documented early bacteraemia had a moderately strong signal, while those who had documented late bacteraemia had a stronger signal with more protein concentrations elevated on two separate occasions a week apart.

CONCLUSIONS: Culture-confirmed early and late bacteraemia are accompanied/followed by systemic inflammatory responses not seen with presumed early and late bacteraemia.