Related Experiment Videos
Temporal changes in the population genetics of Salmonella pullorum
S V Dodson1, J J Maurer, P S Holt
1Department of Avian Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602, USA.
Avian Diseases
|December 28, 1999
Summary
Recent genetic changes in Salmonella pullorum may explain failures in pullorum disease testing. This study used random amplified polymorphic DNA (RAPD) to analyze S. pullorum strains, revealing distinct genetic patterns in recent isolates.
Area of Science:
- Veterinary Microbiology
- Poultry Health
- Bacterial Genetics
Background:
- Pullorum disease, caused by Salmonella pullorum, leads to high poultry mortality and white diarrhea.
- Serologic pullorum testing has shown reduced efficacy in detecting early-stage infections in recent decades.
- Potential genetic alterations in S. pullorum may underlie the observed diagnostic challenges.
Purpose of the Study:
- To investigate genetic variations in Salmonella pullorum strains from different eras.
- To correlate genetic profiles with diagnostic test performance.
- To examine the distribution of key virulence genes in S. pullorum isolates.
Main Methods:
- Random Amplified Polymorphic DNA (RAPD) typing was employed to analyze S. pullorum isolates from the 1990s and pre-1980s.
- Three RAPD polymerase chain reaction primers were used to generate DNA profiles.
- Virulence genes (spvB, invA) and fimbrial genes (sef) were assessed in avian Salmonella isolates.
Main Results:
- Eight distinct DNA patterns were identified among 40 S. pullorum isolates using RAPD.
- A shared RAPD pattern was found in 62% of isolates, predominantly from recent infections.
- While most S. pullorum possessed virulence and invasion genes, significant variability in invasion capability was noted.
Conclusions:
- Distinct genetic profiles in recent Salmonella pullorum strains may contribute to diagnostic test limitations.
- The presence of virulence genes does not fully predict the invasive potential of S. pullorum.
- Further research into S. pullorum genetics is crucial for improving disease control strategies in poultry.