Can we Manipulate the Bowel Microbiota and Prevent Anastomotic Leakage in Colorectal Laparoscopic Surgery? Preliminary Results of the MIRACLe Study.

Anastomotic leaks and dehiscences are still the most frequent complication of colorectal surgery and have a multifactorial etiology.

Microbiota refers to the totality of microorganisms in a defined environment. The Microbiome represents the set of genomes of all microorganisms and its environmental relationships. The microbiome performs various and important functions, but above all it contributes to maintaining the integrity of the mucous barrier of the intestinal epithelium.

The composition, biodiversity and functions of the intestinal microbiota vary both longitudinally along the entire intestinal tract from the mouth to the anus, and radially from the muco-epithelial layer to the intestinal lumen. This biodiversity fluctuates with daily variations following various conditions such as diet, physical activity, interactions with people and animals, etc., but remains stable in healthy subjects.

Particular conditions can determine a phenotypic shift of some bacterial families with the development of species with different characteristics, potentially pathogenic which can favor the onset of fistulas and anastomotic dehiscences in experimental setting.

It is known experimentally that the surgical act alone causes a greater change in the composition of the intestinal microbiota. The way in which surgical stress alters the microbiome lies in the mechanisms which the host and the microorganisms communicate. It has recently been shown that mechanical bowel preparation and the administration of antibiotics have an influence on the microbiome. In particular, the mechanical preparation with polyethylene glycol (PEG) and oral antibiotics (OA) can constitute a positive element for surgical outcomes, while intravenous antibiotics very often affect microbiota negatively.