Bacterial DNA content in the intestinal wall from infants with necrotizing enterocolitis

Purpose: The objective of our study was to quantify mucosal bacterial DNA within specimens from neonates undergoing small bowel resection for necrotizing enterocolitis (NEC). Methods: We obtained clinical information and pathologic specimens from all infants diagnosed with NEC who underwent surgical treatment at our institution from 1999 to 2008. Bacterial and human DNA were isolated from paraffin-embedded surgical specimens, and real time polymerase chain reaction was used to amplify bacterial and human genes. Linear regression was used to quantify the amount of human and bacterial DNA in our specimens. Results: From a cohort of 50 infants, we identified 23 infants who underwent both surgical resection and subsequent intestinal reanastomosis. Thirteen (59%) of the neonates had Bell stage III NEC, and 9 (41%) had stage II. There was significantly more bacterial DNA in the resection specimens than in the reanastomosis specimens. This corresponds to a median (interquartile range) increase of 1.81 (1.11-4.69)-fold bacterial DNA in the resection specimen compared with the reanastomosis specimen (P < .05). Conclusion: There is more bacterial DNA in infants with acute NEC compared with the same infants after the NEC had clinically resolved. These findings underscore the potential relevance of adherent or invasive bacteria across the bowel wall in the pathogenesis of NEC.