Submitted to: BMC Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/31/2012
Publication Date: 6/15/2012
Publication URL: http://www.biomedcentral.com/1471-2180/12/108
Citation: Zehr, E.S., Lavrov, D.V., Tabatabai, L.B. 2012. Comparison of Haemophilus parasuis reference strains and field isolates by using random amplified polymorphic DNA and protein profiles. BMC Microbiology. doi:10.1186/1471-2180-12-108. Interpretive Summary: This report compares strains of Haemophilus parasuis, a bacterium which infects swine and causes major economic losses to producers. The DNA and proteins of 15 reference strains and 31 field isolates were analyzed by using molecular biology techniques. The results found that the DNA or protein profiles of the strains and isolates were unique and reproducible. The DNA of the strains and isolates did not change over time but the protein expression did. The length of time that a strain or an isolate is cultured in the lab may affect its protein expression.
Technical Abstract: 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 nontypable 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. 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. 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. Repeated passages of reference strains appeared to have altered WCP lysate profiles when they were compared to more recent field isolates’ profiles, which imply that the age or number of passages of an isolate may affect its protein expression.