Surgical bowel preparation, but not bowel resection, mediates dysbiosis after colon and rectal surgery
Author(s):
Julia Kohn; Harika Nalluri-Butz; Matthew Bobel; Julia Nugent; Sonja Boatman; Elizabeth Baker; Maria Martell; Cyrus Jahansouz; Christopher Staley; Wolfgang Gaertner
Background:
The intestinal microbiota has been associated with alterations in colorectal surgery outcomes, including surgical infections and anastomotic leak; however, perioperative changes in its composition are poorly understood. This study characterizes the perioperative gut microbiome across multiple colorectal interventions.
Hypothesis:
We anticipate the use of oral antibiotics prior to surgery will result in more substantial and persistent derangements in the intestinal microbiota composition compared to patients undergoing colonoscopy.
Methods:
We assessed three cohorts (n=29, 26, 28): (S) colonoscopy with mechanical bowel preparation (MBP), (R) colon resection with MBP + oral antibiotics (SBP), and (N) non-resection colorectal surgery with SBP. Those receiving SBP also received perioperative IV antibiotics. Fecal microbiota were analyzed at 5 points from baseline to 180 days after surgery.
Results:
The cohorts differed by age, sex, and comorbidity, expected due to differing procedural indications (Table 1). Microbiota alpha diversity in both surgical groups was significantly diminished at T0 and T10, while colonoscopy patients retained near-baseline diversity across timepoints (Figure 1). Beta diversity demonstrated clustering of colonoscopy samples with relative enrichment of beneficial Faecalibacterium and Alistipes; Streptococcus was more abundant in the surgical cohorts.
Table 1. Demographic data for cohorts S (colonoscopy), R (resection), and N (non-resection). Significance=p<0.05.
| Characteristic | Colonoscopy
N=29 |
Resection
N=27 |
Non-resection
N=26 |
P-value |
| Age at surgery, median (range) | 49 (21-82) | 59 (42-78) | 62 (35-77) | <0.01 |
| Sex | 0.05 | |||
| Male | 13 | 18 | 7 | |
| Female | 16 | 9 | 19 | |
| Race | 0.74 | |||
| White | 26 | 24 | 24 | |
| Other | 3 | 3 | 2 | |
| Charlson score | 0.01 | |||
| 0 | 15 | 5 | 3 | |
| 1 | 4 | 7 | 6 | |
| 2 | 10 | 15 | 17 | |
| BMI | 26.5 | 28.3 | 29.3 | 0.12 |
| Indication for procedure | ||||
| Screening colonoscopy | 23 | 1 | 1 | |
| Rectal prolapse | 2 | 0 | 12 | |
| Colon or rectal polyp | 3 | 4 | 14 | |
| Colon cancer | 0 | 13 | 0 | |
| Diverticulitis | 3 | 10 | 0 |
Figure 1. Mean relative abundance of fecal microbiota over study course from cohorts S (colonoscopy), R (resection), and N (non-resection). Predominant species are represented at the genus level.
Conclusions:
Our data support the significant impact of MBP+OA on colon microbiota composition regardless of type of colorectal intervention with or without colorectal resection. This suggests future research into the benefits of restoring beneficial intestinal bacteria in the early postoperative period.