Alterations in co-abundant bacteriome in colorectal cancer and its persistence after surgery: a pilot studyOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This pilot study investigated the gut bacteriome in colorectal cancer (CRC) using 16S rRNA gene sequencing of fecal samples. The researchers aimed to identify microbial markers characteristic of CRC and to determine whether CRC-associated changes in bacterial composition persist after surgical treatment. They also examined functional pathway predictions derived from the 16S rRNA gene data to compare CRC and non-cancer samples.
Who was studied?
The study included 49 fecal samples collected from 25 non-cancer (NC) individuals and 12 CRC patients. The CRC patients were sampled both before surgery and again six months after surgery, allowing pre-op and post-op comparisons within the same patients.
What were the most important findings?
CRC patients showed reduced bacterial richness and diversity compared to the non-cancer group, along with increased abundance of pro-carcinogenic bacteria such as Bacteroides fragilis and Odoribacter splanchnicus. These differences between CRC and non-cancer groups were no longer observed after surgery. However, comparing pre-op to post-op CRC samples revealed that while probiotic bacteria increased after surgery, bacteria associated with CRC progression also increased, suggesting persistent dysbiosis. Functional pathway predictions further showed differential enrichment of various pathways between CRC and non-cancer samples.
What are the greatest implications of this study?
The findings suggest that CRC is associated with a distinct microbiome signature, including elevated Bacteroides fragilis, that is not fully resolved by surgical removal of the tumor. The persistence of dysbiotic elements after surgery implies a possible field-change effect in the remnant colon, meaning surgery alone may not restore a healthy microbial community. This raises the possibility that residual dysbiosis could contribute to disease recurrence and that post-surgical microbiome monitoring or intervention may warrant further investigation.