title: Comparative leukotoxicities of Pasteurella haemolytica isolates from domestic sheep and free-ranging bighorn sheep (Ovis canadensis).
abstract: Twenty-eight isolates of Pasteurella haemolytica from domestic sheep (n = 14 isolates) and bighorn sheep (n = 14 isolates) were evaluated for leucotoxicity against peripheral blood neutrophils of bighorn sheep by adding bacterial culture supernatants to bighorn sheep neutrophils in vitro. Leukotoxic isolates of P. haemolytica, defined as causing > 50% neutrophil death as measured by release of lactate dehydrogenase into culture supernatants, were identified from eight of 14 domestic sheep isolates and from 0 of 14 bighorn sheep isolates. The in vitro assay of isolates of P. haemolytica may provide a valid predictive measure of strain virulence of P. haemolytica, and of potential pneumonic episodes in bighorn sheep populations.
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040.
authors.forename: S J
authors.initials: SJ
authors.lastname: Sweeney
authors.forename: R M
authors.initials: RM
authors.lastname: Silflow
authors.forename: W J
authors.initials: WJ
authors.lastname: Foreyt
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000633:toxicity; D003603:Cytotoxins / Q000096:biosynthesis / Q000633:toxicity; D005098:Exotoxins / Q000096:biosynthesis / Q000633:toxicity*; D005260:Female; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D016978:Mannheimia haemolytica / Q000472:pathogenicity*; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology; D010326:Pasteurella Infections / Q000382:microbiology / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology*; D014774:Virulence
chemical_list: D001427:Bacterial Toxins; D003603:Cytotoxins; D005098:Exotoxins; C018579:leukotoxin; D007770:L-Lactate Dehydrogenase