Gastrointestinal surgery and the gut microbiome: a systematic literature review.

Abstract

The impact of gastrointestinal surgery on the profile of the human gut microbiome is not fully understood. This review aimed to identify whether there is a change to the profile of the gut microbiome as a result of gastrointestinal surgery. In August 2018, a systematic literature search was conducted in Medline, PreMedline, Embase, CINAHL and The Cochrane Register of Clinical Trials, identifying and critically appraising studies which investigated changes to gut microbiome pre- and post-gastrointestinal surgery. Of 2512 results, 14 studies were included for analysis. All studies reported post-surgical change to the microbiome. In 9 of the 14 studies, prevalence of specific bacteria had significantly changed after surgery. Improved outcome was associated with higher levels of beneficial bacteria and greater microbiome diversity post-surgery. There were methodological limitations in the included studies leading to uncertainty regarding the impact of gastrointestinal surgery alone on the microbiome profile. An ideal future model for research should encompass case-controlled or cohort design with longer term follow-up in a homogeneous patient group. Future research should seek to clarify the gold standard testing method and standardised timing for post-surgical microbiome sample collection. It is imperative that controls for confounders be put in place to attempt to identify the true association between gastrointestinal surgery and changes to gut microbiome.