Translocation of coagulase-negative bacterial staphylococci in rats following intestinal ischemia-reperfusion injury.
Many patients with sepsis have bacteremia for which no septic focus is identified either clinically or by autopsy. This study was designed to determine the relationship between the ischemia-reperfusion injury (IRI) and bacterial translocation that might be involved in the pathogenesis of necrotizing enterocolitis. In the first experiment, a total of 32 Sprague-Dawley rats weighing 150-200 g were divided into four groups. The mesentery to isolated loop was occluded for 30, 60, and 90 min following 30-min reperfusion in the three groups of experimental animals with a micro-bulldog clamp. A control group involved the same technique and exposure, without occlusion of the mesentery. Two sets of blood culture were taken through a catheter in the portal vein immediately and 15 min after the reperfusion, respectively. In another experiment, bacteria isolated were fed in different doses to control rats and those after 30- or 60-min ischemia and 30-min reperfusion. Two sets of blood culture were taken following the procedure. Invasion and transcytosis of the bacteria through epithelial cells were studied in vitro using a Madin-Derby canine kidney (MDCK) cell monolayer model. PCR for delta toxin gene was performed on all bacteria isolated, using Staphylococcus epidermidis as the control. Coagulase-negative staphylococci (CoNS) were invariably isolated from mice with prolonged ischemia (90 min) and reperfusion. When bacteria were fed into mice with only 30-min ischemia, an inoculum as low as 5 x 10(5) CFU/ml could induce bacteremia. No bacterial translocation was found in control mice even fed with a higher dose of bacteria (5 x 10(8) CFU/ml). In vitro experiments showed that CoNS failed to transcytose MDCK monolayer. These isolates were not cytotoxic to MDCK cells and contained no delta toxin gene. Bacterial translocation of CoNS occurred following severe bowel ischemia and reperfusion injury. Intact mucosa integrity readily prevented bacterial translocation; however, bacterial translocation could occur in rats following mild IRI in the presence of a higher number of CoNS in the gut.
Luo
Chih-Cheng
CC
Departments of Pediatric Surgery and Pediatrics, Chang Gung Children's Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan. lifen@adm.cgmh.org.tw
Shih
Hsiang-Hung
HH
Chiu
Cheng-Hsun
CH
Lin
Jer-Nan
JN
D000818:Animals; D018988:Bacterial Translocation / Q000502:physiology*; D003030:Coagulase / Q000172:deficiency; D015169:Colony Count, Microbial; D004285:Dogs; D007410:Intestinal Diseases / Q000382:microbiology* / Q000473:pathology; D007413:Intestinal Mucosa / Q000382:microbiology / Q000473:pathology; D007422:Intestines / Q000098:blood supply; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051379:Mice; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000382:microbiology* / Q000473:pathology; D018805:Sepsis / Q000382:microbiology / Q000473:pathology; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000473:pathology; D013210:Staphylococcus / Q000201:enzymology / Q000502:physiology*
D003030:Coagulase; D007770:L-Lactate Dehydrogenase