Necrotising enterocolitis: is there a relationship to specific pathogens?

Outbreaks of necrotising enterocolitis (NEC) have often been related to spe cific pathogens such as Enterobacteriaceae. This relationship, however, rem ains uncertain because of the retrospective nature of the studies addressin g this issue. We performed a prospective study to investigate whether there is indeed an association between NEC and specific pathogens. Between April 1993 and March 1997, stools of neonates of < 36 weeks admitted to our neon atal unit were investigated for bacteria in weekly intervals. Clinical and bacteriological data from each infant who developed NEC were compared with those from two control infants matched for gestational age and date of admi ssion. Eighteen infants developed 19 episodes of NEC (clinical signs + air in portal vein); 8 of these had laparotomy; two died. Occurences of NEC wer e homogeneously distributed over the 4-year study period. The only signific ant differences in the clinical course prior to NEC were a more severe stag e of respiratory distress syndrome [median 2 (0-4) vs, 0 (0-3), P < 0.05] a nd a higher proportion of infants who had only been formula fed (63 vs. 32% , P < 0.05) in the cases. Within the last week prior to NEC, potentially pa thogenic bacteria were identified in stools of all cases and 79% of control s (P < 0.05). However, there was no significant difference in the occurrenc e of specific pathogens or groups of pathogens in cases compared with contr ols. Conclusion Although gut colonisation with potential pathogens appeared to b e a prerequisite for the development of NEC, there were no specific bacteri a associated with this disease if data from infants with NEC were compared with those from time- and gestational age-matched controls.