title: Prevalence of Shiga toxin-producing and enteropathogenic Escherichia coli marker genes in diarrhoeic stools in a New Zealand catchment area.
abstract: BACKGROUND
  Shiga toxin-producing (STEC) and enteropathogenic (EPEC) Escherichia coli are gastrointestinal pathogens causing diarrhoeal and extraintestinal disease. Due to lack of EPEC screening and use of Sorbitol-MacConkey (SMAC) agar in faecal screening, the true prevalence of EPEC and non-O157 STEC in New Zealand diarrhoeal cases is unknown.
  
  
  METHODS
  Diarrhoeic stools sourced from Dunedin hospital were pre-enriched, DNA extracted with Chelex-100 resin and screened using a multiplex TaqMan quantitative PCR assay amplifying stx1, sxt2 and EPEC (eae) gene markers.
  
  
  RESULTS
  Of the 522 diarrhoeic samples surveyed, 8 (1.53%) were PCR positive for stx1/stx2 and 23 (4.41%) were positive for eae. Six (75%) of the stx+samples were uncommon non-O157 serotypes, and the remainder were found to be positive for both O103 and O157 STEC somatic antigens.
  
  
  CONCLUSIONS
  Results revealed shortcomings in current screening protocols for pathogenic E. coli; SMAC is not sufficiently discriminatory to detect emergent STEC serotypes and EPEC likely has an unappreciated role in cases of diarrhoea in New Zealand.
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Rowan R
authors.initials: RR
authors.lastname: Thomas
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Heather J L
authors.initials: HJ
authors.lastname: Brooks
authors.affiliation: Disease Research Laboratory, Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Rory
authors.initials: R
authors.lastname: O'Brien
mesh_terms: D003967:Diarrhea / Q000382:microbiology*; D054308:Enteropathogenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D005243:Feces / Q000382:microbiology*; D006801:Humans; D009520:New Zealand; D016133:Polymerase Chain Reaction; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D029968:Escherichia coli Proteins
keywords: E COLI; INFECTIOUS INTESTINAL DISEASE; MICROBIAL PATHOGENIC; MICROBIOLOGY; PCR