Human microbiome analysis of anastomotic tissue in patients with anastomotic leaks: a potential role for Enterococcus

OBJECTIVE: To develop a microbiome analytical pathway for anastomotic tissue and to profile the human microbiome in colorectal anastomotic tissue. METHODS:  Patients at a single-institution undergoing distal colorectal... [ view full abstract ]

OBJECTIVE: To develop a microbiome analytical pathway for anastomotic tissue and to profile the human microbiome in colorectal anastomotic tissue.

METHODS:  Patients at a single-institution undergoing distal colorectal operations with a planned primary anastomosis were prospectively enrolled. All patients underwent preoperative oral antibiotic and mechanical bowel preparation. The proximal and distal tissue “donuts” from an end-to-end anastomotic stapling device were collected. The microbial DNA was isolated from the wash using a Fecal DNA isolation kit (Zymo). 16S DNA sequences were processed, integrated, analyzed using the QIIME program and reported using in house software. Taxonomy was assigned to 16S sequences using ribosomal database program classifier against the Greengenes 16S rRNA database.

RESULTS:  Twelve patients were included which yielded 24 total anastomotic donuts. 11 of the 12 patients underwent a sigmoidectomy; the majority were performed laparoscopically (75%). Indications included diverticular disease (58%), colorectal cancer (33%), and inflammatory bowel disease (8.3%). 2 of the 12 patients were diagnosed with an anastomotic leak. 43 microbes were identified to be significantly different between the leak and no leak patients. Compared to the no leak group, genus Enterococcus in the leak group was found to be significantly 10-fold more abundant (3.6 vs 0.27%, p<0.05).  

CONCLUSIONS:  Enterococcus was observed to be significantly more abundant in patients with a postoperative anastomotic leak compared with no leak. These findings support studies in rodent models that show higher amounts of enterococcus in anastomotic leaks. Further investigation into the potential role of Enterococcus in anastomotic leaks needs to be evaluated.