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

Objective:investigation of bacterial invasion into the intestinal wall in necrotizing enterocolitis (nec) specimens.study design: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.results: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.conclusion: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.