Characterization and comparison of Pasteurella multocida strains associated with porcine pneumonia and atrophic rhinitis.
One hundred and fifty-eight porcine strains of Pasteurella multocida, recovered primarily from cases of pneumonic pasteurellosis or progressive atrophic rhinitis (PAR) in England and Wales, were characterized by determination of their capsular types, presence or absence of the toxA gene and molecular mass heterogeneity of the heat-modifiable (OmpA) and porin (OmpH) proteins. Eighteen groups (clones) of strains were identified on the basis of specific combinations of capsular type, toxA status and outer-membrane protein (OMP)-type. The data provided evidence that different subpopulations of P. multocida are responsible for pneumonia and PAR in pigs. The majority (88 %) of cases of pneumonia were associated exclusively with non-toxigenic capsular type A strains of OMP-types 1.1, 2.1, 3.1 and 5.1 and capsular type D isolates of OMP-type 6.1. These strains were recovered from widespread geographical locations within England and Wales over a 12-year period and represented mostly single sporadic cases. The association of a small number of P. multocida variants with the majority of cases of porcine pneumonia suggests that these strains are not opportunistic pathogens of low virulence but represent primary pathogens with a relatively high degree of virulence. In contrast, the majority (76 %) of cases of PAR were associated with toxA-containing capsular type D strains of OMP-type 4.1 and capsular type A and D strains of OMP-type 6.1. Toxigenic capsular type A strains associated with PAR and non-toxigenic capsular type A strains associated with pneumonia represent distinct subpopulations of P. multocida that can be differentiated by their OMP-types. The association of capsular types A and D with strains of the same OMP-types, and the absence and presence of the toxA gene in strains of the same OMP-types, suggest that horizontal transfer of capsular biosynthesis and toxA genes has occurred between strains representing certain subpopulations of P. multocida.
Davies
Robert L
RL
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
MacCorquodale
Roslyn
R
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
Baillie
Susan
S
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
Caffrey
Bridget
B
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
D000818:Animals; D016667:Bacterial Capsules / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques; D005798:Genes, Bacterial / Q000235:genetics; D016979:Pasteurella multocida / Q000235:genetics* / Q000302:isolation & purification*; D011014:Pneumonia / Q000382:microbiology* / Q000503:physiopathology / Q000662:veterinary*; D016133:Polymerase Chain Reaction; D012222:Rhinitis, Atrophic / Q000382:microbiology* / Q000503:physiopathology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000503:physiopathology
D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins