title: Effect of growth in cell cultures and strain on virulence of Mycoplasma hyopneumoniae for swine.
abstract: In an attempt to develop better methods for consistent induction of pneumonia in naturally born swine, using cultures of Mycoplasma hyopneumoniae, fifty 6-week-old, naturally born pigs from a respiratory disease-free herd were used in 3 trials. Pigs inoculated with Mycoplasma hyopneumoniae strain 232 (passage 21) grown for 1 passage or 5 passages in Eagle minimal essential medium plus 20% porcine serum, with or without human lung fibroblasts, had a mean (+/- SD) value range between 5.4 +/- 3.6 and 9.2 +/- 2.1% of consolidated lung area. In the second trial, pigs inoculated 1, 2, or 3 days in succession with strain 232 grown in Eagle medium or Friis mycoplasmal medium with 20% porcine serum had between 5.1 +/- 7 and 8.7 +/- 4.3% of consolidated lung area. In the third trial, virulence of Mycoplasma hyopneumoniae strains 144L (p27), 11 (p26), J (p60), and 232 (p27) grown in Friis mycoplasmal medium was compared. Pigs inoculated with those strains had 5.1 +/- 4.1, 2.6 +/- 3.1, 0, and 4.3 +/- 4% of consolidated lung area, respectively. Significant differences were not found in consolidated lung area among groups in trials 1 and 2, and among groups of pigs inoculated with M hyopneumoniae strains 144L, 11, and 232 in trial 3. Pneumonia was not detected in pigs inoculated with strain J in trial 3.
authors.affiliation: Veterinary Medical Research Institute, College of Veterinary Medicine, Iowa State University, Ames 50011.
authors.forename: G C
authors.initials: GC
authors.lastname: Zielinski
authors.forename: R F
authors.initials: RF
authors.lastname: Ross
mesh_terms: D000818:Animals; D001431:Bacteriological Techniques / Q000662:veterinary*; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D006801:Humans; D008171:Lung Diseases / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D009174:Mycoplasma / Q000254:growth & development / Q000472:pathogenicity*; D011014:Pneumonia / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D013045:Species Specificity; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology; D014774:Virulence