title: Detection of genetic diversity by pulsed-field gel electrophoresis among Escherichia coli O157 isolated from bovine faecal samples by immunomagnetic separation technique.
abstract: OBJECTIVE
  Escherichia coli O157 is considered to be one of most important human pathogens of animal origin which causes serious clinical complications. One of the most common methods to isolate E. coli O157 is the immunomagnetic separation (IMS) technique which employs specific antibodies coupled to magnetic beads to bind and extract cells from enrichment broths followed by plating onto sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (CT-SMAC) plates. The aim of this study was to determine strain variation by pulsed-field gel electrophoresis (PFGE) among E. coli O157 on IMS/CT-SMAC plates.
  
  
  RESULTS
  Every suspect colony of E. coli O157 was tested following isolation by the IMS/CT-SMAC technique. From 124 colonies detected; six XbaI-PFGE profiles were identified.
  
  
  CONCLUSIONS
  Our results demonstrate that mixed populations of E. coli O157 with distinguishable PFGE profiles that are simultaneously present in bovine faeces can be isolated with IMS/CT-SMAC technique.
  
  
  CONCLUSIONS
  If the aim of the study was to analyse diversity of PFGE profiles of E. coli O157 in a faecal sample following isolation by the IMS/CT-SMAC technique, at least five colonies per sample should be analysed to detect different PFGE subtypes if present.
authors.affiliation: Molecular Chemotherapy, Centre for Infectious Diseases, University of Edinburgh, Edinburgh, UK.
authors.forename: L
authors.initials: L
authors.lastname: Vali
authors.forename: A
authors.initials: A
authors.lastname: Hamouda
authors.forename: M C
authors.initials: MC
authors.lastname: Pearce
authors.forename: H I
authors.initials: HI
authors.lastname: Knight
authors.forename: J
authors.initials: J
authors.lastname: Evans
authors.forename: S G B
authors.initials: SG
authors.lastname: Amyes
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D014644:Genetic Variation; D018189:Immunomagnetic Separation; D010802:Phylogeny