title: Adherent Escherichia coli in colorectal mucosal biopsies: a histological and ultrastructural evaluation.
abstract: BACKGROUND
  Colorectal mucosal biopsies occasionally demonstrate the presence of bacteria adherent to the epithelium. This study evaluated the histological and ultrastructural correlates of such bacterial adherence.
  
  
  METHODS
  Rectal mucosal biopsies from eight patients in whom histopathological examination of biopsies had earlier demonstrated adherent bacteria were examined by electron microscopy and by bacterial culture. Colorectal biopsies of 69 patients with adherent bacteria detected histologically were retrospectively evaluated for histological changes at sites proximal and distant to adherent bacteria.
  
  
  RESULTS
  Escherichia coli of different serogroups were isolated from 7 of 8 rectal biopsies demonstrating bacterial adherence. All isolates showed diffuse or focal adherence to HEp-2 cell monolayers. Ultrastructural changes noted included microvillus damage, pedestal formation, actin web condensation, and protrusions of the apical cytoplasm of epithelial cells into the lumen towards the bacteria. Histological changes noted at light microscopy included reduction in epithelial cell height, focal epithelial cell degeneration, cryptitis and neutrophil infiltration at sites of bacterial adherence whereas these were usually absent at sites distant to adherent bacteria. Bacterial adherence was noted more often in biopsies from Crohn's disease patients than in patients without this diagnosis (P<0.001).
  
  
  CONCLUSIONS
  Adherent Escherichia coli in colorectal biopsies were associated with focal epithelial damage and showed an association with Crohn's disease.
authors: Global Hospitals, Chennai, Tamil Nadu, India.
authors: Susama
authors: S
authors: Patra
authors: Subash C
authors: SC
authors: Samal
authors: Gagandeep
authors: G
authors: Kang
authors: Anna
authors: A
authors: Pulimood
authors: Minnie
authors: M
authors: Mathan
authors: Balakrishnan S
authors: BS
authors: Ramakrishna
mesh_terms: D001422:Bacterial Adhesion; D001431:Bacteriological Techniques; D001706:Biopsy; D003106:Colon / Q000382:microbiology* / Q000473:pathology; D003424:Crohn Disease / Q000382:microbiology / Q000473:pathology; D004848:Epithelium / Q000382:microbiology / Q000473:pathology; D004926:Escherichia coli / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure*; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology; D008854:Microscopy, Electron; D012007:Rectum / Q000382:microbiology* / Q000473:pathology