Bacterial translocation and change in intestinal permeability in patients after abdominal surgery

The purpose of this study was to investigate bacterial translocation and change in intestinal permeability in patients after abdominal surgery. Sixty-three patients undergoing elective abdominal surgery were enrolled in the study. Blood samples were collected prior to operation and 2, 24, 48 h after surgery for bacterial culture, microbial DNA extraction, plasma D-lactate and endotoxin measurement. PCR analysis was performed after DNA extraction, with beta-lactosidase gene of E. coli and 16S rRNA gene as target genes. All patients were observed for a period of 30 days for infectious complications. Our results showed that no bacterial DNA was detected before surgery, but after operation it was found in 12 patients (19.0%). Bacterial DNA was detected in 41.7% (10/24) of SIRS patients and 5.1% (2/39) of non-SIRS patients (P < 0.01). About 83.3% of PCR-positive patients developed systemic inflammatory response syndrome (SIRS), but only 27.5% of PCR-negative patients did so (P < 0.01). Two thirds of PCR-positive patients developed infectious complications, while none of PCR-negative patients did (P < 0.01). The blood culture was positive only in 3 patients (4.8%), who were all PCR-positive. E. coli DNA was found in 66.7% of the PCR-positive patients. The plasma levels of D-lactate and endotoxin were elevated significantly 2, 24 and 48 h after operation in PCR-positive patients, with a significant positive correlation found between them (r=0.91, P < 0.01). It is concluded that increased intestinal permeability was closely related with bacterial translocation. Intestinal bacterial translocation (most commonly E. coli) might occur at early stage (2 h) after abdominal surgery. Postoperative SIRS and infection might bear a close relationship with bacterial translocation.