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.
Keywords: E COLI; INFECTIOUS INTESTINAL DISEASE; MICROBIAL PATHOGENIC; MICROBIOLOGY; PCR.
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