Spatial Heterogeneity of Escherichia coli DNA Fingerprints Isolated from Cellulitis Lesions in Chickens

• Published in: Avian diseases 1999-10, Vol.43 (4), p.756-762
• Main Authors: Singer, Randall S., Jeffrey, Joan S., Carpenter, Tim E., Cooke, Cara L., Chin, Richard P., Atwill, E. Rob, Hirsh, Dwight C.
• Format: Article
• Language: English
• Subjects: Albs; Animals; Birds; Broiler chickens; Cellulitis; Cellulitis - microbiology; Cellulitis - veterinary; Chickens; DNA; DNA Fingerprinting; DNA, Viral - genetics; Electrophoresis, Gel, Pulsed-Field; Escherichia coli; Escherichia coli - classification; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; Escherichia coli Infections - veterinary; Gels; Genetic heterogeneity; Genetic Variation; Lesions; Phylogeny; Poultry Diseases - microbiology; Poultry Diseases - pathology; Ranches
• ISSN: 0005-2086; 1938-4351
• DOI: 10.2307/1592744

Avian cellulitis in broiler chickens is characterized by subcutaneous lesions that result in economic losses because of the partial or complete condemnation of the carcasses at processing. Escherichia coli is the primary causative agent of this condition. Previous research with a biotyping system found that the E. coli of cellulitis origin were unique to each ranch, suggesting that these E. coli were endemic within the ranch environment. The objective of our study was to analyze the genetic variability of E. coli isolates associated with cellulitis. We analyzed the genetic relatedness of the isolates in relation to the houses, ranches, and complexes in which the broilers were grown. This analysis enabled us to assess the spatial heterogeneity, or genetic diversity on a spatial scale, of the isolates. Forty-nine broilers with cellulitis lesions were necropsied. These broilers came from six houses on four ranches on three complexes that had been placed with chicks from the same hatchery within a 2-wk period. Isolates of E. coli from the lesions were DNA fingerprinted by pulsed-field gel electrophoresis. Relatedness among isolates was determined with the Dice coefficient and an unweighted pair group method with average linkages cluster analysis. The complexes possessed isolates with a variety of DNA fingerprints, yet each complex appeared to have isolates with a unique set of DNA fingerprints. Isolates from the same complex tended to form clusters with similarity coefficients greater than 90%. Isolates from different complexes were genetically distinct. This heterogeneity at the level of the complex suggests that isolates were not disseminated from a source common to the complexes. The spatial heterogeneity of the E. coli isolates in this study implies an endemic population of cellulitis-associated E. coli exists in the broiler house environment. /// La celulitis aviar en pollos de engorde se caracteriza por lesiones subcutáneas que producen pérdidas económicas debido a los decomisos parciales o completos de las canales en la planta de procesamiento. El agente causal primario de esta condición es Escherichia coli. Algunas investigaciones anteriores que han utilizado un sistema de tipificación biológica encontraron que las cepas de E. coli aislada de los casos de celulitis eran únicas para cada granja sugiriendo que estas cepas de E. coli son endémicas dentro del medio ambiente de cada granja. El objetivo de este estudio fue el de analizar la variabilidad gené