Genetic diversity of porcine strains from the respiratory tract of healthy and diseased swine

Astrid Bethe , Lothar H. Wieler , Hans-J. Selbitz , Christa Ewers

A total of 382 porcine strains, isolated from cases of pneumonia and progressive atrophic rhinitis (PAR) as well as from clinically healthy pigs of more than 150 German husbandries were characterized by detection of virulence associated genes (VAGs) and ribotyping to understand the relationships between “commensal” and “pathogenic” strains, enabling a rational choice of vaccine strains. The diversity of the strains according to VAGs was low and mainly limited to capsular type genes (: 53.4%; : 45.8%; : 0.3%; -negative: 0.5%; : 95.3%), dermonecrotoxin gene (3.4%), as well as adhesion-related genes (20.9%) and (84.3%). Ribotyping identified 13 patterns, but the vast majority of strains (95.8%) clustered in only three of these, namely IA-1 (45.5%), IA-7 (30.1%), and IIA-1 (20.2%). Pattern IA-1 was associated with strains (93.6%) and harboured the majority of strains (84.6%). Pattern IA-7 mostly contained , strains (93.9%), while pattern IIA-1 was predominantly composed of , strains (87.0%). Clinical strains associated with pneumonia or PAR shared the above mentioned major ribotypes in comparable proportions with strains derived from healthy pigs, suggesting to act more as an opportunistic than as an obligate pathogen in pigs.

Mots clés: Pasteurella multocida; Porcine respiratory tract; VAG; PCR; Ribotyping

Astrid Bethe, Lothar H. Wieler, Hans-J. Selbitz, Christa Ewers. Genetic diversity of porcine strains from the respiratory tract of healthy and diseased swine. Veterinary Microbiology, 2009, 139 (1-2), pp.97. ⟨10.1016/j.vetmic.2009.04.027⟩. ⟨hal-00520654⟩