E. coli diversity: low in colorectal cancer

Area of Science:

• Microbiology
• Genomics
• Human Health

Background:

• Escherichia coli (E. coli) exists as both commensal and pathogenic strains.
• The population structure (monophyletic vs. polyphyletic) of commensal E. coli, potential precursors to pathogenic strains, remains largely unknown.
• Understanding E. coli diversity is crucial for insights into its association with human health and diseases.

Purpose of the Study:

• To investigate the diversity of commensal E. coli populations in healthy individuals across different age groups and in colorectal cancer (CRC) patients.
• To explore the relationship between E. coli diversity and host health status.

Main Methods:

• Genomic sequencing and pulsed field gel electrophoresis (PFGE) were employed.
• E. coli isolates were analyzed from the intestinal microbiota of preschool children, university students, seniors, and CRC patients.
• 2280 E. coli isolates from 185 subjects were characterized into distinct genome types (genotypes).

Main Results:

• High genomic diversity of E. coli was observed, with individuals often harboring multiple genotypes.
• E. coli diversity increased with age in healthy individuals, from children to seniors.
• Colorectal cancer patients exhibited significantly lower E. coli diversity compared to healthy controls.
• E. coli isolates from CRC patients demonstrated the ability to suppress the growth of E. coli from healthy individuals under nutrient-limited conditions.

Conclusions:

• The coexistence of multiple E. coli lineages may contribute to a host-beneficial microbial environment.
• Reduced E. coli diversity in the gut may be linked to an unhealthy microenvironment, potentially facilitating diseases like colorectal cancer.