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Published on: March 9, 2016
Application of ERIC-PCR for the comparison of isolates of Haemophilus parasuis
M Rafiee1, M Bara, C P Stephens
1Australasian Pig Institute, Queensland Department of Primary Industries, Animal Research Institute, Yeerongpilly, Queensland 4105.
Objective:
To validate a polymerase chain reaction (PCR) based method. Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR), for the fingerprinting of Haemophilus parasuis strains and to use that method to differentiate isolates from apparently related outbreaks of Glässer's disease on three pig farms.
Design:
ERIC-PCR was evaluated by comparing 15 different strains that represented all 15 recognised serovars in the Kielstein-Rapp-Gabrielson (KRG) scheme for serotyping H parasuis. Next, ERIC-PCR was used to examine 14 Australian field isolates of H parasuis; 12 collected from three farms suffering apparently related outbreaks of Glässer's disease and two from two other farms with no known connection.
Results:
The 15 serovar reference strains all gave unique, reproducible ERIC-PCR fingerprints. The 12 isolates from the three apparently related outbreaks all gave a single fingerprint, which was distinct from any seen in the 15 serovar reference strains and the two other Australian field isolates in the studied farms. The confirmation that all 12 isolates were the same strain allowed the development of a prevention and control program that has prevented the emergence of any further outbreaks of Glässer's disease on the three farms.
Conclusion:
ERIC-PCR is a suitable technique for the differentiation of unrelated strains of H parasuis. The finding that the 12 field isolates of H parasuis all shared the same fingerprint is strong evidence that there was a common source of infection on all three farms. This study has shown, for the first time, that ERIC-PCR is a suitable technique for the sub-typing of H parasuis and useful for studying the epidemiology of outbreaks of Glässer's disease.
Insights
Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) effectively differentiates Haemophilus parasuis strains. This method confirmed a common infection source in Glässer
Area of Science:
- Veterinary Microbiology
- Molecular Diagnostics
- Epidemiology
Background:
- Haemophilus parasuis causes Glässer's disease in pigs, leading to significant economic losses in the swine industry.
- Accurate strain differentiation is crucial for understanding disease transmission and implementing effective control strategies.
- Existing serotyping methods for H. parasuis can be laborious and may not always provide sufficient discriminatory power.
Purpose of the Study:
- To validate Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) as a molecular typing tool for Haemophilus parasuis.
- To assess the utility of ERIC-PCR in differentiating H. parasuis isolates from outbreaks of Glässer's disease.
- To investigate the epidemiological links between Glässer's disease outbreaks on multiple pig farms.
Main Methods:
- ERIC-PCR was employed to generate fingerprints for 15 reference strains representing all known serovars of H. parasuis.
- The method was further applied to 14 Australian field isolates, including 12 from three farms experiencing related Glässer's disease outbreaks.
- Fingerprint reproducibility and discriminatory power were evaluated against established serotyping schemes.
Main Results:
- All 15 H. parasuis serovar reference strains produced unique and reproducible ERIC-PCR fingerprints.
- The 12 isolates from the three implicated farms yielded a single, identical ERIC-PCR fingerprint.
- This common fingerprint was distinct from reference strains and other field isolates, indicating a single source of infection.
Conclusions:
- ERIC-PCR is a reliable and suitable technique for differentiating Haemophilus parasuis strains.
- The study provides strong evidence for a common source of infection in the investigated Glässer's disease outbreaks.
- ERIC-PCR is valuable for sub-typing H. parasuis and elucidating the epidemiology of Glässer's disease outbreaks.
