Molecular characterization of avian pathogenic Escherichia coli associated with egg peritonitis in commercial layer chickens
Open Access
- Author:
- Gruenewald, Analise L
- Area of Honors:
- Veterinary and Biomedical Sciences
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Subhashinie Kariyawasam, Thesis Supervisor
Robert John Vansaun, Thesis Honors Advisor - Keywords:
- egg peritonitis
avian pathogenic E coli - Abstract:
- Escherichia coli is a bacterium commonly found as part of the intestinal microflora of many animals. These commensal strains of E. coli are harmless and part of the natural environment of the gut. Other more virulent strains of E. coli exist; however, with various pathologies in many species. In the poultry industry, one type of E. coli is of particular interest; avian pathogenic E. coli (APEC). APEC causes extraintestinal infections in poultry including airsacculitis, septicemia, cellulitis, ompholitis/yolk sac infection in young birds, and peritonitis and salpingitis (when combined referred to as salpingoperitonitis) in laying birds. These combined pathologies are known as colibacillosis. Of all these conditions, salpingoperitonitis particularly afflicts the commercial egg laying industry through death and decreased production in layer hens. Furthermore, only few studies have been done to characterize the subpathotype of APEC associated with layer peritonitis. Thus, it is important to add to the knowledge base regarding these pathogenic strains to improve strategies to eliminate the disease. The objective of this study was to characterize a collection of APEC (n=40) isolated from the ovaries, oviducts, and peritoneum of commercial layer hens diagnosed with E. coli salpingoperitonitis in comparison to a collection (n=10) of commensal E. coli isolated from the ceca of apparently healthy hens. Methods of characterization included virulence genotyping using PCR, phylogenetic grouping, and pulsed-field gel electrophoresis. The results of the study revealed a diverse group of isolates, with a few clusters of apparently identical isolates. Pathogenic isolates were more virulent than commensal isolates, as expected. Atypical results regarding phylogenetic grouping reinforce the need to continue studying different outbreaks of APEC in laying hens.