title: Synergistic action of E. coli endotoxin and Pasteurella multocida type A for the induction of bronchopneumonia in pigs.
abstract: This study aimed to investigate whether Escherichia coli endotoxin (LPS) may predispose the lung to an infection with Pasteurella multocida type A (Pma) and to determine the LPS concentration needed to reproduce clinical signs of bronchopneumonia. Twenty-four hours before inoculating Pma or sterile growth medium, piglets were tracheally instilled with 10, 100 or 400 microg/kg LPS. Cough, body temperature, daily weight gain (DWG) bronchoalveolar lavage fluid (BALF) cells and volume of pneumonic lung were measured. Changes in breathing pattern (Penh) were assessed by whole body barometric plethysmography. No significant changes were observed in Pma-treated or in control animals. Each LPS doses induced DWG reduction while the higher generated a severe subacute interstitial pneumonia causing hyperthermia and an increase in Penh. The combination of the lower LPS doses with Pma produced an asymptomatic bronchopneumonia leading to DWG reduction, rise in Penh and an increase in BALF macrophages and neutrophils. With 400 microg/kg LPS, Pma worsened the inflammatory process as illustrated by cough, hyperthermia, major DWG reduction and by a greater Penh response. Lung lesions consisted of severe exudative bronchopneumonia. We concluded that LPS may negatively influence growth, predispose to persisting lung inflammatory process and promote Pma infection depending on the dose previously administered.
authors.affiliation: Department for Functional Sciences, Faculty of Veterinary Medicine, Unit of Pharmacology, Pharmacotherapy and Toxicology, University of Liège, Boulevard de Colonster B-41, 4000 Liège, Belgium.
authors.forename: David J
authors.initials: DJ
authors.lastname: Halloy
authors.forename: Nathalie A
authors.initials: NA
authors.lastname: Kirschvink
authors.forename: Jacques
authors.initials: J
authors.lastname: Mainil
authors.forename: Pascal G
authors.initials: PG
authors.lastname: Gustin
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001992:Bronchoalveolar Lavage Fluid; D001996:Bronchopneumonia / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D004269:DNA, Bacterial / Q000032:analysis; D004731:Endotoxins / Q000633:toxicity*; D004927:Escherichia coli Infections / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D008070:Lipopolysaccharides / Q000633:toxicity*; D010326:Pasteurella Infections / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D016979:Pasteurella multocida / Q000235:genetics / Q000472:pathogenicity*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012720:Severity of Illness Index; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D004269:DNA, Bacterial; D004731:Endotoxins; D008070:Lipopolysaccharides; C044101:endotoxin, Escherichia coli