Microbiome

Benjamin D. Shogan, MD, FACS, FASCRS

Over the last few decades a new frontier has been discovered: the human microbiome. Completed in 2012, the National Institutes of Health Human Microbiome Project used the newly developed 16S ribosomal ribonucleic acid sequencing technology to give us our first insight into this newly appreciated ecosystem. These initial investigations led us to discover that the variety of organisms inhabiting the human host is wider than ever imagined, and include not just bacteria, but fungi, archaea, viruses, and protozoa. Since, there has been an explosion of interest into the role of the microbiome, catalyzing the generation of newer technologies and microbiome-focused institutes to deeply investigate how the composition and function of the microbiota precisely define the importance of the host–microbe interaction.

Of all the various ecosystems that colonize the human, the gut microbiome has emerged as potentially the vastest. It is now estimated that the gastrointestinal tract contains over 100 trillion microbial cells, with the highest concentration of microbes residing within the colon. These microbes contribute an estimated 50-fold more genes compared with the host, significantly expanding the functionality of the genome. This collaborative relationship between host and microbe are vital for normal homeostasis within the gut such as metabolism, barrier function, and regulation of the local immune system. Further, it has become apparent that the importance of intestinal microbes is not only isolated to maintaining gut health, but rather, gut bacteria has been shown to influence homeostasis in such distant sites such as the gut-brain axis, gut-liver axis, and more recently the gut-eye axis.

Given the density and functional role of the microbes that colonize the colon, it is therefore not surprising that perturbations of the gut microbiome have been found to influence the pathogenesis and severity of colorectal diseases. Further, owing to tissue trauma, creation of an anaerobic environment aerobic, and the influx of inflammatory and healing mediators, colorectal surgery can be considered an ecological earthquake; it would therefore stand to reason that resultant microbial changes can influence postoperative outcomes. As the science matures and microbial-based interventions are developed, it will be critical that surgeons who care for patients with colorectal diseases are knowledgeable about the current state of this exciting field.

In this current issue of Clinics in Colon and Rectal Surgery, we review the emerging role of the gut microbiome pertinent to colon and rectal surgery. Our guest authors represent an international panel of experts that are leading the cutting edge of microbial sciences. We provide introductory articles on the techniques used to study the microbiome, aimed to give a foundation for those interested in the development of their own microbial research program or to critically evaluate the existing microbial-based literature. Further articles provide a rationale for the role of microbes in the development of common surgical diseases such as inflammatory bowel disease, colorectal cancer, and diverticulitis. Finally, we explore how the gut microbiome may influence outcomes such as surgical site infections and anastomotic leak, and discuss strategies to preoperatively optimize the gut.

We hope that you enjoy this special edition of Clinics in Colon and Rectal Surgery. Completion of this edition will give the interested reader a broad view on the current field of microbial science related to colon and rectal surgery and inspire excitement for the future.

Publication History

Article published online:
25 January 2023