Bacteria: a major pathogenic factor for anastomotic insufficiency

Abstract

The aim of this study was to determine the influence of bacteria on the development of anastomotic insufficiency following gastrectomy in the rat. Fifty-seven male Wistar rats were randomly assigned to three groups and subjected to gastrectomy. Group I (n = 20) was orally inoculated with 109 Pseudomonas aeroginosa organisms on postoperative day 1. Group II (n = 20) served as the control group. Group III (n = 17) was decontaminated with 320 mg of tobramycin, 400 mg of polymyxin B, and 500 mg of vancomycin per liter of fluid administered from preoperative day 7 to postoperative day 10. Swabs from the oropharynx and rectum were cultured and analyzed daily for gram-positive and gram-negative bacteria. Surviving animals were sacrificed on postoperative day 10. All animals were autopsied immediately following death. Anastomotic insufficiency was defined as a histologically proven transmural defect at the suture line. Along with an effective reduction of pathogenic bacteria colonizing the oropharynx, the rate of anastomotic insufficiency could be reduced significantly, to 6% in decontaminated animals compared with 80% in controls (P < 0.001 by Fisher's exact test). Inoculation of group I animals with P. aeruginosa led to an increase of anastomotic insufficiency up to 95% and a significant increase in mortality (P < 0.05). We conclude that bacteria play a major role in the pathogenesis of anastomotic insufficiency following gastrectomy in the rat.Anastomotic insufficiency is one of the major causes of morbidity and mortality following total gastrectomy. The pathogenesis of esophago-intestinal anastomotic insufficiency, however, is not completely understood. Impaired blood supply or local microcirculatory disturbances leading to necrosis (13), as well as foreign bodies (6, 7), have been thought to be the cause of anastomotic insufficiency for more than 100 years. Anastomotic insufficiency, however, is a septic disease. Exogenous or endogenous potentially pathogenic microorganisms colonizing the digestive tract may play a causative role in the pathogenesis in addition to microcirculatory disturbances. This idea led us to examine the influence of bacterial colonization on the incidence of anastomotic insufficiency.By topical application of nonresorbable bactericidal antibiotics (16, 18), the colonizing microflora of the oropharynx and upper gastrointestinal tract can be easily manipulated. We therefore used deliberate colonization and topical decontamination with tobramycin, polymyxin and vancomycin to test the following hypotheses in an experimental study: (i) anastomotic insufficiency occurs as a result of bacterial infection, and (ii) anastomotic insufficiency can be prevented by preventing bacterial colonization. MATERUILS AND METHODSFifty-seven male Wistar rats were randomly assigned to three groups. In group I (bacterial inoculation), all animals received one oral dose of 109 Pseudomonas aeruginosa organisms on the first postoperative day. P. aeruginosa was chosen because it is commonly causes nosocomial infections i...

Are gut bacteria associated with the development of anastomotic leaks?

“…In the colons prepared with neomycin and erythromycin, which were continued into the postoperative period, no adverse effect of the in induced ischemia and no AL was found [4]. These results lend support to the results of Cohn [5] and Le Veen [11], and, We carried out the first animal experiments examining the protective effect of topical antibiotic prophylaxis following upper gastrointestinal surgery and were the first to suggest that P. aeruginosa might play a causative role in AL [20]. In the latter trial, rats undergoing total gastrectomy were orally inoculated with P. aeruginosa on postoperative day 1, in order to contaminate the anastomoses.…”

“…Germfree rats also had highly significantly lower AL rates than normal controls using topical antibiotics (p = 0.0002) [21]. We concluded that in addition to poor surgical technique and impaired blood supply to the intestinal anastomosis, bacteria play a major role in the pathogenesis of AL [20].…”

The occurrence of Enterococcus faecium and faecalis Is significantly associated With anastomotic leakage After pancreaticoduodenectomy

“…Almost 40 years later in 1994, a study group identified Pseudomonas aeruginosa as a possible microbial agent associated with leakage after a gastrectomy in rats (17). In this study, rats were allocated into three groups: the first group was inoculated with P. aeruginosa, the second was a control group, and the third was decontaminated with antibiotics.…”

Proceedings of the First International Summit on Intestinal Anastomotic Leak, Chicago, Illinois, October 4–5, 2012

“…In 1985, Steven Cohn performed a similar study in rats showing that oral antibiotics prevented anastomotic leaks completely in devascularized colon segments with complete healing and resolution of ischemia [18]. A seminal study reconfirming the role of microbes as causative agents was then performed in 1994 when Schardey et al demonstrated that introduction of pathogenic bacteria to a newly formed rat anastomosis directly causes anastomotic leak [19]. In a clinical followup, his group then performed a multi-center placebo-controlled, blinded prospective randomized clinical trial (RCT) in 1996 demonstrating that oral decontamination prevent anastomotic leak following gastro-esophageal surgery [20].…”