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dc.contributor.advisorBrooks, Heather
dc.contributor.advisorO'Brien, Rory
dc.contributor.authorThomas, Rowan Ryland
dc.date.available2016-04-07T03:50:03Z
dc.date.copyright2016
dc.identifier.citationThomas, R. R. (2016). Detection of Shiga-toxigenic and enteropathogenic Escherichia coli in diarrhoeic stools (Thesis, Master of Medical Laboratory Science). University of Otago. Retrieved from http://hdl.handle.net/10523/6354en
dc.identifier.urihttp://hdl.handle.net/10523/6354
dc.description.abstractShiga-toxigenic Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) are recognised to be significant contributors to intestinal and extra-intestinal disease and infantile diarrhoea worldwide. In New Zealand, STEC serotype O157:H7 is a notifiable pathogen. The routine use of sorbitol MacConkey (SMAC)-based agar to detect O157:H7 fails to detect many potentially pathogenic non-O157 E. coli serogroups and EPEC is not currently under surveillance. As a result, the contribution of these pathogens to diarrhoeal disease is likely to be underrepresented in governmental surveillance reports. The intent of this project was to develop a multiplex qRT-PCR TaqMan assay suitable for the detection of STEC (stx1 and stx2) and EPEC (eaeA/intimin) marker genes, and to use this assay to survey diarrhoeic stool samples sourced from Dunedin Hospital. Prevalences of 1.53% and 4.41% (95% CI) were found for STEC and EPEC respectively, with 75% of stx+ samples possessing STEC belonging to serogroups other than O157. A trend towards an increased rate of STEC infection amongst samples also tested for Helicobacter pylori was also noted, indicating possible confusion of symptoms by clinicians. The project also tested a number of DNA extraction methods and pre-enrichments to further adapt the assay to high-throughput diagnostic practice. The inexpensive Chelex-100 resin performed satisfactorily when compared with phenol-chloroform and PrepMan Ultra methods. Trypticase soy broth was found to offer the most consistent pre-enrichment for STEC compared to other commonly used non-selective liquid culture media. A 3 hour pre-enrichment of spiked faecal samples was found to boost the sensitivity of the qRT-PCR method to detect 2 x 10^2 CFU per g of faeces.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectShiga
dc.subjectEscherichia
dc.subjectcoli
dc.subjectSTEC
dc.subjectEPEC
dc.titleDetection of Shiga-toxigenic and enteropathogenic Escherichia coli in diarrhoeic stools
dc.typeThesis
dc.date.updated2016-04-07T01:50:53Z
dc.language.rfc3066en
thesis.degree.disciplineDepartment of Microbiology and Immunology
thesis.degree.nameMaster of Medical Laboratory Science
thesis.degree.grantorUniversity of Otago
thesis.degree.levelMasters
otago.openaccessOpen
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