Liljebjelke, KarenBhatt, Krishna2016-10-042016-10-0420162016http://hdl.handle.net/11023/3377This study was conducted to determine antimicrobial and metal resistance, associated resistant genes, and mobile genetic elements in contemporary (2012-2016, n=63) and historical (1980’s, n=31) clinical isolates of Histophilus somni from feedlot cattle in Alberta. A significant increase in antimicrobial resistance was observed in the contemporary isolates compared to the historical (P<0.001). Sixty-two percent of the contemporary isolates exhibited multidrug resistance (resistance to 3 drug classes). Sixty-eight percent and 52% of the contemporary isolates showed tolerance to copper and zinc concentrations above one millimolar, respectively. Multicopper oxidase and cation efflux pump genes associated with copper and zinc tolerance and tet(H) gene associated with oxytetracycline resistance were identified. We identified integrative conjugative element carrying antimicrobial, copper, and zinc resistance genes, which indicates the possibility of co-selection of antimicrobial resistance due to copper and zinc selection pressure, and the dissemination of resistance by horizontal gene transfer.engUniversity 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.MicrobiologyBiology--MolecularVeterinary Scienceantimicrobial resistanceHistophilus somnifeedlot cattlecopperzincmetal tolerancemaster thesis10.11575/PRISM/25268