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[Relationship between serotype, virulence and SDS-PAGE protein patterns of Haemophilus parasuis]
H Rosner1, P Kielstein, W Müller
1Institut für bakterielle Tierseuchenforschung Jena.
Abstract:
141 Haemophilus (H.) parasuis and 8 H. parasuis-like strains from different farms were serotyped according to Morozumi and Nicolet (1986 b) as well as to Bakos et al. (1952). It was possible to classify 72.8% of the investigated strains. 7 out of 12 serotypes have been described for the first time. The high specificity in the agar gel precipitation test was not reproducible in the more sensitive dot-blot procedure. The dot-blot results point to a participation of non-immunogenic polysaccharides in the detection reaction. The serotypes SV 1, SV 5, SV Jena 6 and SV Jena 10 proved to be highly virulent in SPF pigs, SV 2 and SV 4 were of medium virulence. The other serotypes were found to be nonvirulent. Unencapsulated strains and isolates of serotype SV 5 prevailed in animals with Glasser's disease. 23 H. parasuis and 3 H. parasuis-like strains were examined in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). On the basis of protein profiles of whole-cell lysates, 23 of them could be assigned to 5 groups. Apart from the highly virulent strains of serovar 1, which belonged to PAGE type III, all other highly virulent strains of the serovars SV 5, SV Jena 6 and SV Jena 10 were grouped into PAGE type I. No correlation could be found between PAGE type on the one hand and virulence or origin of isolates on the other hand.
Insights
This study serotyped Haemophilus parasuis strains, identifying new serotypes and finding that some are highly virulent in pigs. Virulent strains, particularly serotype SV 5, were linked to Glasser
Area of Science:
- Veterinary Microbiology
- Bacteriology
- Swine Diseases
Context:
- Haemophilus parasuis is a significant swine pathogen causing Glasser's disease.
- Accurate identification and characterization of H. parasuis strains are crucial for disease control.
- Existing serotyping methods have limitations in specificity and reproducibility.
Purpose:
- To serotype Haemophilus parasuis and H. parasuis-like strains using established methods.
- To evaluate the virulence of different serotypes in specific pathogen-free (SPF) pigs.
- To correlate serotype and virulence with protein profiles obtained via SDS-PAGE.
Summary:
- Serotyping classified 72.8% of 141 H. parasuis and 8 H. parasuis-like strains, with 7 new serotypes identified.
- Highly virulent serotypes (SV 1, SV 5, SV Jena 6, SV Jena 10) were identified in SPF pigs; serotype SV 5 and unencapsulated strains were prevalent in Glasser's disease cases.
- SDS-PAGE grouped strains into 5 types, with virulent strains predominantly in PAGE type I or III, but no direct correlation was found between PAGE type and virulence or origin.
Impact:
- Identifies novel H. parasuis serotypes and characterizes their virulence, aiding in vaccine development and strain differentiation.
- Highlights potential issues with dot-blot assays due to non-immunogenic polysaccharides, suggesting refinement of diagnostic methods.
- Provides insights into the genetic diversity and virulence factors of H. parasuis, contributing to better understanding and management of swine respiratory diseases.