Extraintestinal pathogenic Escherichia coli (ExPEC) strains are important pathogens that cause diverse diseases in humans and poultry. Some E. coli isolates from chicken feces contain ExPEC-associated virulence genes, so appear potentially pathogenic; they conceivably could be transmitted to humans through handling and/or consumption of contaminated meat. However, the actual extraintestinal virulence potential of chicken-source fecal E. coli is poorly understood. Here, we assessed whether fecal E. coli isolates from healthy production chickens could cause diseases in a chicken model of avian colibacillosis and three rodent models of ExPEC-associated human infections. From 304 E. coli isolates from chicken fecal samples, 175 E. coli isolates were screened by PCR for virulence genes associated with human-source ExPEC or avian pathogenic E. coli (APEC), an ExPEC subset that causes extraintestinal infections in poultry. Selected isolates genetically identified as ExPEC and non-ExPEC isolates were assessed in vitro for virulence-associated phenotypes, and in vivo for disease-causing ability in animal models of colibacillosis, sepsis, meningitis, and urinary tract infection. Among the study isolates, 13% (40/304) were identified as ExPEC; the majority of these were classified as APEC and uropathogenic E. coli, but none as neonatal meningitis E. coli. Multiple chicken-source fecal ExPEC isolates resembled avian and human clinical ExPEC isolates in causing one or more ExPEC-associated illnesses in experimental animal infection models. Additionally, some isolates that were classified as non-ExPEC were able to cause ExPEC-associated illnesses in animal models, and thus future studies are needed to elucidate their mechanisms of virulence. These findings show that E. coli isolates from chicken feces contain ExPEC-associated genes, exhibit ExPEC-associated in vitro phenotypes, and can cause ExPEC-associated infections in animal models, and thus may pose a health threat to poultry and consumers.
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- Evaluation of Escherichia Coli Isolates From Healthy Chickens to Determine Their Potential Risk to Poultry and Human Health
- Stromberg, Zachary R. (Author)
- Johnson, James R. (Author)
- Fairbrother, John M. (Author)
- Kilbourne, Jacquelyn (Author)
- Van Goor, Angelica (Author)
- Curtiss, Roy (Author)
- Mellata, Melha (Author)
- ASU Biodesign Center Immunotherapy, Vaccines and Virotherapy (Contributor)
- Biodesign Institute (Contributor)
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Digital object identifier: 10.1371/journal.pone.0180599
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Identifier TypeInternational standard serial numberIdentifier Value1045-3830
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Identifier TypeInternational standard serial numberIdentifier Value1939-1560
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The article is published at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180599
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Stromberg, Z. R., Johnson, J. R., Fairbrother, J. M., Kilbourne, J., Goor, A. V., Curtiss, R., & Mellata, M. (2017). Evaluation of Escherichia coli isolates from healthy chickens to determine their potential risk to poultry and human health. Plos One, 12(7). doi:10.1371/journal.pone.0180599