Colonic adenoma-associated Escherichia coli express specific phenotypes

Cecilia Ambrosi, Meysam Sarshar, Maria Rita Aprea, Arianna Pompilio, Giovanni Di Bonaventura, Francesco Strati, Annamaria Pronio, Mauro Nicoletti, Carlo Zagaglia, Anna Teresa Palamara, Daniela Scribano

Research output: Contribution to journalArticlepeer-review


Specific Escherichia coli strains have been associated to colorectal cancer, while no data are available on genotypic and phenotypic features of E. coli colonizing premalignant adenomatous polyps and their pathogenic potential. This study was aimed at characterizing isolates collected from polyps and adjacent tissue in comparison with those from normal mucosa. From colonoscopy biopsies, 1500 E. coli isolates were retrieved and genotyped; 272 were characterized for phylogroup and major phenotypic traits (i.e., biofilm formation, motility, hemolysins, and proteases). Selected isolates were analyzed for extraintestinal pathogenic E. coli (ExPEC)-associated virulence genes and in vivo pathogenicity using Galleria mellonella. The majority of isolates collected from polyps were strong biofilm and poor protease producers, whereas those isolates from normal mucosa were highly motile, proteolytic and weak biofilm formers. Isolates from adjacent tissues shared features with those from both polyps and normal mucosa. Among selected E. coli isolates, ExPEC gene content/profile was variable and uncorrelated with the tissue of collection and larval mortality. Despite the heterogeneous virulence-gene carriage of the E. coli intestinal population, E. coli colonizing colonic adenomatous polyps express specific phenotypic traits that could represent an initial pathoadaptation to local environmental changes characterizing these lesions.

Original languageEnglish
Pages (from-to)305-312
Number of pages8
JournalMicrobes and Infection
Issue number7
Publication statusPublished - Aug 1 2019


  • Biofilm
  • Colonic adenomatous polyp
  • Escherichia coli
  • ExPEC
  • Galleria mellonella
  • Virulence factors

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Infectious Diseases


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