Comparison of Haemophilus parasuis reference strains and field isolates by using random amplified polymorphic DNA and protein profiles.
BACKGROUND
Haemophilus parasuis is the causative agent of Glässer's disease and is a pathogen of swine in high-health status herds. Reports on serotyping of field strains from outbreaks describe that approximately 30% of them are nontypeable and therefore cannot be traced. Molecular typing methods have been used as alternatives to serotyping. This study was done to compare random amplified polymorphic DNA (RAPD) profiles and whole cell protein (WCP) lysate profiles as methods for distinguishing H. parasuis reference strains and field isolates.


RESULTS
The DNA and WCP lysate profiles of 15 reference strains and 31 field isolates of H. parasuis were analyzed using the Dice and neighbor joining algorithms. The results revealed unique and reproducible DNA and protein profiles among the reference strains and field isolates studied. Simpson's index of diversity showed significant discrimination between isolates when three 10 mer primers were combined for the RAPD method and also when both the RAPD and WCP lysate typing methods were combined.


CONCLUSIONS
The RAPD profiles seen among the reference strains and field isolates did not appear to change over time which may reflect a lack of DNA mutations in the genes of the samples. The recent field isolates had different WCP lysate profiles than the reference strains, possibly because the number of passages of the type strains may affect their protein expression.
Ruminant Diseases and Immunology, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA. emilie.zehr@ars.usda.gov
Emilie S
ES
Zehr
Dennis V
DV
Lavrov
Louisa B
LB
Tabatabai
D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis*; D001431:Bacteriological Techniques / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics*; D044137:Haemophilus parasuis / Q000737:chemistry* / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods*; D015203:Reproducibility of Results; D013552:Swine
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D020543:Proteome