Microbial Changes in Opioid-Induced Colonic Anastomotic Leak
Author(s):
Baddr Shakhsheer, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; James Luo, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Scott Christley, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Jennifer DeFazio, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Robin Klabbers, Radboud University Nijimegen Medical Centre, Department Of Surgery, Nijimegen, Gelderland, Netherlands; Kristina Guyton, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Monika Krezalek, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Natalia Belogortseva, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Alexander Zaborin, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; Olga Zaborina, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA; John Alverdy, Pritzker School Of Medicine, University Of Chicago, Department Of Surgery, Chicago, IL, USA
Background: Opioid analgesics are ubiquitously used following gastrointestinal surgery and have many undesirable effects such as delayed intestinal transit, intestinal bacterial overgrowth, and increased incidence of surgical site infections. Previous work from our lab demonstrated that opioids can induce intestinal bacteria to express enhanced virulence against the intestinal epithelium.
Hypothesis: Opioids alter anastomotic healing leading to leakage via their effect on the intestinal microbiota - agents we have recently shown play a key and causative role in anastomotic leak.
Methods: Rats underwent distal colectomy with anastomosis and were implanted with a slow-release morphine pellet or placebo pellet in the subcutaneous neck. Rats were sacrificed on post-operative day six and autopsied for gross signs of anastomotic leak. Local anastomotic tissues were examined by high magnification microscopy. Composition and function of microbial populations in anastomotic tissues was determined by 16S rRNA and PICRUST analyses. Recovered bacterial species were tested for collagenolytic activity.
Results: Morphine treated rats developed a ~50% leak rate compared with a 3% leak rate in the placebo group. High powered imaging of the anastomotic site showed visible disruption of the anastomoses with mucosal ulceration in the morphine group but not in placebo group. 16S rRNA analysis revealed a bloom in abundance of Escherichia/Shigella (avg 0.56% at POD0 vs 32% at POD6) and Bacteroides (avg 3.9% at POD0 vs 24% at POD6) in both placebo and morphine post-operative groups. PICRUST analysis predicted a shift of microbial population metabolism at POD6 to biosynthesis of lipopolysaccharides, sphingolipid and lipoic acid metabolism leading to production of bioactive signaling lipid molecules involved in the apoptosis and adhesion regulation. There were no significant differences in microbial composition and function in post-operative tissues between groups. Only Enterococcus faecalis and Proteus mirabilis were able to produce high collagenase activity in in vitro assays. In all cases where both collagenase producing E. faecalis and P. mirabilis were not recovered, there was no leak, suggesting them as critical players when in combination.
Conclusions: Anastomotic leak in rats under morphine treatment is associated with the colonization of anastomotic tissues by a pair of high collagenase producing strains of E. faecalis and P. mirabilis at the background of a profound distortion of microbial composition and function.