Characterization of the genetic diversity and antimicrobial resistance in Mannheimia haemolytica from feedlot cattle

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Klima, Cassidy L.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2009
Mannheimia haemolytica is an opportunistic pathogen in cattle and the main bacterial agent in bovine respiratory disease. Despite its economic importance, few studies have characterized the genetic diversity of M. haemolytica, particularly from feedlots. Three genotyping techniques (BOX-PCR, (GTG)5-PCR and PFGE) were compared to discriminate M. haemolytica and strains from the family Pasteurellaceae. PFGE was the most discriminating and repeatable, although BOX-PCR was most accurate in clustering isolates together according to species. Mannheimia haemolytica was isolated from nasal swab samples collected from cattle upon entry and exit from two feedlots in southern Alberta. These were characterized by PFGE and antimicrobial susceptibility using a disk-diffusion assay. Select gene determinants were screened for using PCR. PFGE analysis revealed the isolates to be highly diverse. Ten percent of the isolates exhibited resistance. At present, the development and spread of antimicrobial resistance in M. haemolytica observed within the feedlots examined appears to be low.
xi, 116 leaves : ill. ; 29 cm
Bovine pneumonic pasteurellosis , Pathogenic bacteria , Cattle -- Pathogens -- Research , Cattle -- Diseases -- Research , Feedlots , Dissertations, Academic