Peptostreptococcus

Role in Gut Ecosystem#

Low-abundance member of the normal gut microbiota that expands dramatically under dysbiotic conditions, particularly in the CRC tumor microenvironment.^{[1]Reproducible and opposing gut microbiome signatures distinguish autoimmune diseases and cancers: a systematic review and meta-analysisMd Zohorul Islam, Melissa Tran, Tao Xu et al. · 2022Open reference 1 ↓}

Iron-dependent organism; its expansion in CRC may be facilitated by the iron-rich environment of bleeding tumors and the disrupted Nutritional Immunity (Metal Sequestration) landscape of the tumor microenvironment.^{[2]Beyond Taxonomic Analysis of Microbiomes: A Functional Approach for Revisiting Microbiome Changes in Colorectal CancerNorouzi-Beirami MH, Marashi SA, Banaei-Moghaddam AM et al. · 2020Open reference 2 ↓}

Part of the oral-gut translocation pathway—normally abundant in the oral cavity, Peptostreptococcus can colonize the colon when oral barrier function is compromised or gastric acid is suppressed.^{[3]Bacterial Variation in the Oral Microbiota in Multiple Sclerosis PatientsZangeneh Z, Abdi-Ali A, Khamooshian K et al. · 2021Open reference 3 ↓}

Colorectal Cancer#

Among the top 3 most consistently enriched genera in CRC across the Islam 2022 meta-analysis of 27 CRC studies, alongside Fusobacterium and Porphyromonas.^{[1]Reproducible and opposing gut microbiome signatures distinguish autoimmune diseases and cancers: a systematic review and meta-analysisMd Zohorul Islam, Melissa Tran, Tao Xu et al. · 2022Open reference 1 ↓}

Enriched in both old-onset and young-onset CRC, demonstrating a consistent CRC-microbiome signature.^{[6]Consistent signatures in the human gut microbiome of old- and young-onset colorectal cancerYouwen Qin, Xin Tong, Wei-Jian Mei et al. · 2024Open reference 6 ↓}

Listed in the Hanus 2021 comprehensive catalog of bacteria involved in colorectal carcinogenesis alongside F. nucleatum, enterotoxigenic B. fragilis, and pks+ Escherichia coli.^{[4]Immune System, Microbiota, and Microbial Metabolites: The Unresolved Triad in Colorectal Cancer MicroenvironmentHanus M, Parada-Venegas D, Landskron G et al. · 2021Open reference 4 ↓}

Periodontal Disease#

Core member of the subgingival pathogenic consortium in periodontitis. Oral Peptostreptococcus may translocate to the gut, contributing to the oral-gut-axis in CRC development.

Key Metabolites#

Indoleacrylic acid—tryptophan derivative; increases IL-10 (anti-inflammatory) in oral context. ROS-inducing factors—promote oxidative DNA damage in colonic epithelium. Cholesterol pathway activators—drive epithelial proliferation in CRC.