• INTESTINAL MICROBIOLOGY
• COLORECTAL SURGERY
• GASTROINTESTINAL SURGERY
• IMMUNE RESPONSE

Surgery is the definitive treatment for colorectal cancer and anastomotic leak (AL) remains its most feared complication. Advances in enhanced recovery, surgical technique and intraoperative imaging have had a relatively modest impact in reducing the incidence of this life-threatening event.1 A major reason for this has been that the molecular mechanisms of anastomotic wound healing are incompletely understood.

The study by Hajjar et al provides further evidence that the microbiome represents a critical missing piece in this puzzle because it modulates the innate immune response to anastomotic wound healing.2 The more intriguing observation from this work is that it is possible to transfer a colonic healing phenotype through the transplantation of preoperative faecal samples and even individual bacterial strains. The implications of this finding for perioperative optimisation of the gut prior to surgery are significant.

The authors recruited patients undergoing elective colorectal surgery for colorectal cancer (n=77). Both faecal and mucosal colonic samples were taken before and after surgery (by rectal swab at postoperative day). In this single centre cohort, nine patients experienced an anastomotic leak, and they were matched to an age, sex and cancer stage cohort that did not leak (n=9). Faecal samples were then transplanted into antibiotic-conditioned female C57BL/6 mice which were in turn subjected to a colotomy wound healing model.

Fascinatingly, preoperative stool transplanted from those patients that leaked induced …