Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk
Thesis (PhD)--University of Pretoria, 2017.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2018
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613601114619904 |
|---|---|
| access_status_str | Open Access |
| author2 | Buys, E.M. (Elna Maria) |
| author_browse | Buys, E.M. (Elna Maria) |
| author_facet | Buys, E.M. (Elna Maria) |
| collection | Thesis |
| dc_rights_str_mv | © 2018 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2017. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/65932 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:43.836Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2018 |
| publishDateRange | 2018 |
| publishDateSort | 2018 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/65932 Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk Buys, E.M. (Elna Maria) u13183690@tuks.co.za Njage, Patrick Murigu Kamau Ntuli, Victor UCTD Thesis (PhD)--University of Pretoria, 2017. Several recent large outbreaks of gastrointestinal diseases have highlighted the threat posed by morbidity and mortality associated with shigatoxin-producing Escherichia coli (STEC). Furthermore, the treatment of STEC infections is now threatened by the emergence of antibiotic resistance which is an alarming health concern in the world of medicine. The most implicated STEC in foodborne disease outbreaks across the globe is O157 serotype, although some emerging STEC non-O157 serotypes are increasingly becoming recognised as foodborne pathogens of important public health concern. This study was undertaken to characterise bacterial species in raw and pasteurised producer-distributor bulk milk (PDBM) with specific emphasis on E. coli and other Enterobacteriaceae. E. coli was further investigated for the prevalence and distribution of virulence factors (stx 1, stx 2 and hlyA), serotypes and antibiotic resistance patterns, which also included extended-spectrum ?-lactamase (ESBL) producing capacity. Subsequently, the study further estimated the haemolytic uraemic syndrome (HUS) risk associated with the consumption of STEC contaminated PDBM and also estimated the resulting burden of illness that may be associated with the consumption of such milk in South Africa (SA). A total of 258 PDBM samples were collected, using convenience sampling, from outlets (purchase points) in eight different geographical provinces in SA. Isolation, detection and enumeration of total aerobic bacteria, coliforms and E. coli were carried out using 3M E. coli /coliform petrifilm plates. Matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) was used for the rapid identification of the bacterial isolates. The identification of E. coli was confirmed using PCR of the uidA gene. Further characterisation of E. coli into serogroups, identification of virulence factors and antibiotic resistance profiles were then performed. E. coli O157 was characterised using selective media and confirmed using mismatch amplification mutation assay (MAMA)-multiplex PCR. Identification of E. coli -serogroups was carried out by the restriction of amplified O-antigen gene cluster (rfb-RFLP), coupled with serum agglutination assay. Virulence factors (stx 1, stx 2 and hlyA) were determined using both phenotypic and genotypic characterisation. Antimicrobial agent susceptibility tests and detection of extended spectrum beta-lactamase (ESBL) producing capacity of the E. coli isolates were performed using phenotypic characterisation. Finally, a quantitative risk assessment for STEC in PDBM was also conducted. More than 60% of the PDBM samples were found not to be fit for human consumption on the basis of the minimum standards prescribed in the Foodstuffs, Cosmetics and Disinfectants Act (Act 54 of 1972). Raw and pasteurised PDBM was contaminated with a wide diversity of Enterobacteriaceae species, which included spoilage microbiota. Food Science PhD Unrestricted 2018-07-25T09:01:00Z 2018-07-25T09:01:00Z 2018/04/19 2017 Thesis Ntuli, V 2017, Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/65932> A2018 http://hdl.handle.net/2263/65932 en © 2018 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk |
| title | Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk |
| title_full | Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk |
| title_fullStr | Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk |
| title_full_unstemmed | Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk |
| title_short | Shigatoxin producing Escherichia coli O157 and non-O157 serotypes in producer-distributor bulk milk |
| title_sort | shigatoxin producing escherichia coli o157 and non o157 serotypes in producer distributor bulk milk |
| topic | UCTD |
| url | http://hdl.handle.net/2263/65932 |