OCCURRENCE OF NECROTIZING ENTEROCOLITIS MAY BE DEPENDENT ON PATTERNS OF BACTERIAL ADHERENCE AND INTESTINAL COLONIZATION - STUDIES IN CACO-2TISSUE-CULTURE AND WEANLING RABBIT MODELS

Necrotizing enterocolitis (NEC) is one of the leading causes of death in neonatal intensive care units. The underlying pathophysiology of NE C is poorly defined, although there is a suggestion that bacterial age nts play an important role in the process. In this study, we evaluated bacterial isolates from 17 NEC cases and matched asymptomatic control infants. Isolates from NEC patients were no more likely than control isolates to be adherent to enterocytes, as assessed by a Caco-2 cell t issue culture model. Adherent Escherichia coli isolates, from both NEC cases and controls, were able to cause pathologic changes typical of NEC in a weanling rabbit ileal leap model. Adherence of E. coli strain s to Caco-2 cells, and subsequent production of disease in weanling ra bbits, could be blocked by coinfection with Gram-positive isolates fro m control children. In contrast, in three of four instances, adherent E. coli from NEC cases retained their adherence and caused illness in rabbits when coinfected with Grampositive isolates from the homologous child. Our data suggest that patterns of intestinal adherence, as inf luenced by the underlying intestinal microbial ecology, play a role in the pathophysiology of NEC.