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Characterizing avian Escherichia coli isolates with multiplex polymerase chain reaction
Jerod A Skyberg1, Shelley M Horne, Catherine W Giddings
1Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58105, USA.
Avian Diseases
|January 8, 2004
Summary
A new multiplex PCR method rapidly identifies virulence genes in avian Escherichia coli, aiding in poultry disease diagnosis. This technique helps differentiate disease-causing strains from harmless ones, improving poultry health management.
Area of Science:
- Veterinary Microbiology
- Molecular Diagnostics
- Poultry Science
Background:
- Colibacillosis, caused by Escherichia coli, leads to significant economic losses in the poultry industry.
- Avian E. coli virulence mechanisms are not fully understood, hindering effective disease control.
- Several virulence genes, often located on transmissible plasmids, are associated with avian E. coli pathogenicity.
Purpose of the Study:
- To develop and describe a multiplex polymerase chain reaction (PCR) protocol for detecting key avian E. coli virulence genes.
- To provide a rapid diagnostic tool for characterizing E. coli isolates from poultry.
- To assess the correlation between the presence of specific virulence genes and disease severity in poultry.
Main Methods:
- Developed a multiplex PCR assay targeting four avian E. coli virulence genes: iss, tsh, cvi, and iucC.
- Utilized known E. coli strains with and without these genes as DNA templates for protocol optimization.
- Confirmed amplicon identity through size analysis, DNA:DNA hybridization, and DNA sequencing.
- Applied the multiplex PCR protocol to characterize E. coli isolates from diseased and healthy poultry.
Main Results:
- Isolates from diseased birds predominantly contained three or more virulence genes (8/10 isolates), while isolates from healthy birds generally had fewer (9/10 isolates had ≤1 gene).
- One isolate from a healthy bird possessed all four genes and caused the highest embryo mortality in its group.
- Isolates from sick birds with only two target genes exhibited the lowest embryo lethality.
- The PCR protocol demonstrated specificity for E. coli, as the target genes were absent in non-E. coli isolates.
Conclusions:
- The developed multiplex PCR protocol offers a rapid and specific method for characterizing avian E. coli virulence.
- The presence and number of the targeted virulence genes correlate with the pathogenicity of E. coli in poultry.
- This protocol can supplement existing diagnostic methods, aiding in the identification and study of disease-causing E. coli strains in poultry.