Comparison of a shiga toxin enzyme-linked immunosorbent assay and two types of PCR for detection of shiga toxin-producing Escherichia coli in human stool specimens.

Shiga toxin (Stx)-producing Escherichia coli (STEC) is a major cause of sporadic cases of disease as well as serious outbreaks worldwide. The spectrum of illnesses includes mild nonbloody diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. STEC produces one or more Stxs, which are subdivided into two major classes, Stx1 and Stx2. The ingestion of contaminated food or water, person-to-person spread, and contact with animals are the major transmission modes. The infective dose of STEC may be less than 100 organisms. Effective prevention of infection is dependent on rapid detection of the causative bacterial pathogen. In the present study, we examined 295 stool specimens for the presence of Stx-producing E. coli by three different methods: an Stx enzyme-linked immunosorbent assay, a conventional PCR assay, and a LightCycler PCR (LC-PCR) assay protocol recently developed by our laboratory at the Institute of Medical Microbiology at Hannover Medical School. Our intent was to compare these three methods and to examine the utility of the STEC LC-PCR protocol in a clinical laboratory. The addition of a control DNA to each sample to clearly discriminate inhibited specimens from negative ones enhanced the accuracy of the LC-PCR protocol. From our results, it can be concluded that LC-PCR is a very useful tool for the rapid and safe detection of STEC in clinical samples.

Influence of postoperative epidural analgesia with bupivacaine on intestinal motility, transit time, and anastomotic healing.

Epidural application of bupivacaine has been suggested to have a sympatholytic effect on spinal reflex mechanisms that shortens postoperative paralysis and leads to an improved transit time. The influence on anastomitic healing remains controversial. Laparotomy was performed in eight dogs. A short segment of the distal colon was resected and five electrodes were fixed on the serosa to measure the myoelectric activity (e.g., Migrating Myoelectric Complex--MMC). After operation a peridural catheter was placed between L7 and the sacral crest. One milliliter of bupivacaine 0.25% for each 3 kg of body weight was injected every 4 hours. Barium pellets coated in wax were placed into the stomach to allow radiographic representation of transit time. After 5 days the colon anastomosis was resected to measure the bursting pressure. In the peridural analgesia group (PDA) we found one small bowel intussusception and one covered anastomotic leakage. Postoperative PDA led to early and severe myoelectric activity but did not influence the time until the first MMC occurred (44 +/- 0.8 h, PDA; 44.6 +/- 1.5 h,control). Neither the transit time to the colon (50.2 +/- 1.9h, PDA; 51.7 +/- 5.5 h, control) nor the anastomotic healing was influenced (bursting pressure: 176 +/- 21.1 mmHg, PDA; 152 +/- 27.7 mmHg, control). Postoperative epidural analgesia with bupivacaine shortens intestinal paralysis. Early myoelectric activity with a lack of propulsive activity can cause complications like small bowel intussusception. Hence early postoperative enteral nutrition after epidural analgesia is risky. Because the influence of epidural analgesia on propulsive motility remains unclear, it seems reasonable to recommend its limited use in colon surgery.