Identification of bacterial invasion in necrotizing enterocolitis specimens using fluorescent in situ hybridization.

Abstract

Investigation of bacterial invasion into the intestinal wall in necrotizing enterocolitis (NEC) specimens. We compared 43 surgical NEC specimens with 43 age-matched controls. We used fluorescent in situ hybridization (FISH), a universal bacterial probe together with species-specific probes for Clostridium spp., Enterobacteriaceae, bacteroides and enterococci/lactobacilli. We used a FISH scoring system to reveal invasion of the intestinal wall, in which 1 represented no colonies and 4 invasion of the intestinal wall. We observed invasion of the intestinal wall in 22/43 of the most affected NEC tissue samples as compared with 16/43 in the least affected NEC tissue samples (P=0.03). A FISH score of 4 was reached in 7/43 control cases. Enterobacteriaceae dominated the NEC specimens. Clostridium spp. were detected occasionally in NEC samples. Bacterial invasion of the intestinal wall is more present in most affected NEC tissue samples compared with least affected NEC tissue samples or controls. Enterobacteriaceae are prevalent in advanced NEC.