Colonic adenoma-associated Escherichia coli express specific phenotypes

Area of Science:

• Microbiology
• Gastroenterology
• Oncology

Background:

• Specific Escherichia coli strains are linked to colorectal cancer.
• Limited data exists on the genotypic and phenotypic features of E. coli in adenomatous polyps.

Purpose of the Study:

• To characterize E. coli isolates from polyps, adjacent tissues, and normal mucosa.
• To compare their genotypic and phenotypic traits, including pathogenic potential.

Main Methods:

• 1500 E. coli isolates from colonoscopy biopsies were genotyped.
• 272 isolates were analyzed for phylogroup, biofilm formation, motility, hemolysins, and proteases.
• Selected isolates were assessed for extraintestinal pathogenic E. coli (ExPEC) virulence genes and in vivo pathogenicity in Galleria mellonella.

Main Results:

• E. coli from polyps were strong biofilm producers and poor protease producers.
• E. coli from normal mucosa were highly motile, proteolytic, and weak biofilm formers.
• ExPEC gene content varied and did not correlate with tissue source or larval mortality.

Conclusions:

• E. coli colonizing colonic adenomatous polyps exhibit specific phenotypic traits.
• These traits may indicate initial pathoadaptation to the altered microenvironment of polyps.
• E. coli's role in colorectal cancer may involve specific adaptations within polyps.