title: Partial characterization of the leukotoxin of Pasteurella haemolytica-like bacteria isolated from swine enteritis.
abstract: Pasteurella haemolytica-like (PHL) strains isolated from diarrheic pigs are known to produce a leukotoxin that is lethal to ruminant leukocytes. In the present study, 12 PHL strains were screened for leukotoxin production using a tetrazolium dye-reduction assay. Sterile culture supernatant from strain 6213A, the maximum leukotoxin producer, was used as the crude leukotoxin for characterization studies. The leukotoxin was inactivated by heat at 60 degrees C and by trypsin, protease, and amylase. Toxicity was retained over a pH range of 3.0-11.0. The leukotoxin was lethal to polymorphoneutrophils (PMNs) of cattle, sheep, goat, and swine. Chromosomal DNA of all 12 PHL strains hybridized with a 3.9 kb Pasteurella haemolytica A1 leukotoxin probe, indicating similarities between the leukotoxin genes of P. haemolytica and PHL strains.
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis* / Q000633:toxicity; D002417:Cattle; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary; D004751:Enteritis / Q000382:microbiology / Q000662:veterinary*; D005098:Exotoxins / Q000032:analysis* / Q000633:toxicity; D066298:In Vitro Techniques; D007700:Kinetics; D016978:Mannheimia haemolytica / Q000235:genetics / Q000302:isolation & purification*; D009504:Neutrophils / Q000187:drug effects / Q000473:pathology; D010326:Pasteurella Infections / Q000382:microbiology / Q000662:veterinary*; D013045:Species Specificity; D013552:Swine; D013553:Swine Diseases
chemical_list: D001427:Bacterial Toxins; D004269:DNA, Bacterial; D005098:Exotoxins; C018579:leukotoxin