Characterization of antibiotic resistance in ampicillin and tetracycline resistant escherichia coli from feedlot cattle fed subtherapeutic antimicrobials

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dc.contributor.advisorMcAllister, Tim
dc.contributor.advisorLouie, Marie
dc.contributor.authorMirzaagha, Parasto
dc.date.accessioned2017-12-18T21:44:48Z
dc.date.available2017-12-18T21:44:48Z
dc.date.issued2008
dc.descriptionBibliography: p. 118-131en
dc.descriptionsome pages are in colouren
dc.description.abstractThe study investigated tetracycline- and ampicillin-resistant Escherichia coli selected from feces of calves that were or were not administered in-feed subtherapeutic antimicrobials. Antimicrobial resistance (AMR) persisted throughout the experiment even in the absence of in-feed antibiotics. Transmission of E. coli isolates among cattle was evident, particularly among animals within a single pen. In addition, shedding of E. coli biotypes was observed to occur transiently throughout the feeding period. Administration of subtherapeutic levels of antimicrobials did not have a major impact on AMR E. coli as compared to control steers, except for the observation that administration of chlortetracycline and sulfamethazine increased the number of ampicillin-resistant isolates that also exhibited resistance to sulfamethoxazole and chloramphenicol. Molecular characterization of isolates found tet(B) to be the most prevalent determinant among the tetracycline-resistant isolates and teml-like determinant to be most prevalent among the ampicillin-resistant isolates. Results suggest that AMR inĀ£. coli is complex and is likely affected not only by the administration of antibiotics but also by numerous other presently undefined environmental and management factors.
dc.format.extentxii, 131 leaves : ill. ; 30 cm.en
dc.identifier.citationMirzaagha, P. (2008). Characterization of antibiotic resistance in ampicillin and tetracycline resistant escherichia coli from feedlot cattle fed subtherapeutic antimicrobials (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/2302en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/2302
dc.identifier.urihttp://hdl.handle.net/1880/103303
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.titleCharacterization of antibiotic resistance in ampicillin and tetracycline resistant escherichia coli from feedlot cattle fed subtherapeutic antimicrobials
dc.typemaster thesis
thesis.degree.disciplineMicrobiology & Infectious Diseases
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameMaster of Science (MSc)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 1810 520708973
ucalgary.thesis.notesUARCen
ucalgary.thesis.uarcreleaseyen
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