Spontaneous endotoxinemia in premature infants: correlations with oral feeding and bowel dysfunction

Infants admitted to a tertiary care nursery were tested serially to determine the frequency and epidemiology of spontaneous endotoxinemia, a phenomenon suggested by previous studies. Plasma and stools were tested for endotoxin-like activity (ELA) using a Limulus amoebocyte lysate method and results were correlated with clinical data. We detected ELA in plasma of 28 of 47 infants (60%) tested throughout their hospital stay: only two of 58 separate episodes could be attributed to infection. Endotoxinemia was not consistently associated with classical signs of fever, shock, and jaundice. Prior to oral feeding, little or no ELA was detected in stools and endotoxinemia was ascertained in only six of 45 infants (13%). With feeding, fecal ELA concentrations rose sharply, and endotoxinemia was detected in 56% of remaining infants (p less than 0.001). Bowel disease predisposed to endotoxinemia: 16 of 20 infants (80%) with necrotizing entercolitis or difficult establishment on feeding were affected, compared to five of 17 infants (29%) without such problems (p less than 0.01). Fecal ELA concentrations were not abnormally elevated in those with bowel disease. We conclude that endotoxinemia occurs commonly in immature infants as their fecal flora develops with feeding but the amount of circulating endotoxin required for injury and the patterns this takes require further investigation.