腹部外科手术后肠道细菌移位及肠道屏障的研究

Clinical study on bacterial translocation and gut barrier dysfunction in postoperative patients

目的 应用聚合酶链反应 (PCR)方法及血浆D 乳酸检测 ,来探讨腹部外科手术后肠黏膜屏障损伤与肠道细菌移位 (BT)及BT与感染并发症之间的联系。方法 6 3例择期腹部外科手术患者 ,术前和术后 2、 2 4、 4 8h采集外周血 ,进行全血细菌DNA检测、血D 乳酸、内毒素 (LPS)浓度检测及血细菌培养。患者观察 30d以监测感染并发症。结果 术前PCR均为阴性 ,术后PCR阳性 12例。术后出现全身炎症反应综合征 (SIRS)的患者PCR阳性率为 4 1 7% (10 / 2 4 ) ,明显高于无SIRS组的 5 1% (2 / 39) (P <0 0 1)。PCR阳性组SIRS发生率为 83 3% (10 / 12 ) ,阴性组为 2 7 5 % (14 / 5 1) ,差异有显著性意义 (P <0 0 1)。PCR阳性者 6 6 6 7% (8/ 12 )发生感染并发症 ,阴性者无一发生 (P <0 0 1)。术后血细菌培养阳性率 4 8% (3/ 6 3) ,显著低于PCR的 19 0 % (12 / 6 3) (P <0 0 1) ;血细菌培养阳性者 ,PCR均呈阳性。PCR阳性结果中大肠杆菌DNA阳性率占 6 6 7%。PCR阳性的患者外周血浆D 乳酸及LPS浓度较PCR阴性者明显升高 (P <0 0 1) ,二者呈显著正相关 (r=0 91,P <0 0 1)。结论 腹部外科术后肠黏膜屏障损伤与BT关系密切 ,术后早期 (2h)即可发生BT ,以大肠杆菌为主。

Objective To investigate bacterial translocation and gut barrier dysfunction in postoperative patients using PCR and plasma D-lactate measurement. Methods Sixty-three patients undergoing selective laparotomy were studied. Blood samples were collected before surgery and 2, 24, 48 h after surgery for bacterial culture.Microbial DNA was detected by PCR, plasma D-lactate and LPS measurement. PCR was performed after DNA extraction, with target β-lactosidase gene of E. coli and 16S rRNA gene of most pathogenic bacteria. All patients were observed 30d for infectious complications.Results No bacterial DNA was detected before surgery, but it was positive in 12 patients (19.0%) postoperatively. Bacterial DNA was discovered in 41.7% (10/24) of SIRS patients and 5.1% (2/39) of non-SIRS patients (P<0.01). Eighty-three point three percent(10/12) of PCR-positive patients manifested SIRS, but only 27.5%(14/51) of PCR-negative patients did so (P<0.01). Two thirds(8/12) 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. Among the PCR positive patients, E.coli DNA was found in 66.7%(8/12). The plasma levels of D-lactate and endotoxin elevated significantly at 2, 24 and 48h postoperatively in PCR-positive patients, with a significant correlation between them(r=0.91,P<0.01).Conclusion Gut barrier dysfunction,postoperative SIRS,and infection have a close relationship with bacterial translocation. Intestinal bacterial translocation (most commonly E.coli) might occur in the early stage (2 h) after abdominal surgery.