Proteolytic bacteria in the lower digestive tract of poultry may affect avian influenza virus pathogenicity

M. D. King, M. N. Guentzel, B. P. Arulanandam, B. Lupiani, J. P. Chambers

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Proteolytic cleavage of hemagglutinin is required for cell entry by receptor-mediated endocytosis and plays a key role in pathogenicity of the influenza virus. Despite several studies describing relationships between bacterial proteases and influenza A viral activation in mammals, very little is known about the role of the normal bacterial flora of birds on hemagglutinin activation. We examined the indigenous intestinal microflora of 100 mixed-sex, 27-d-old Ross chickens from a commercial poultry facility for protease-secreting bacteria. Protease-secreting bacteria were isolated from 82 of 100 chickens with 50 birds exhibiting 2 or more protease-secreting bacterial species. A total of 20 protease-secreting bacterial species were identified: 17 gram-positive cocci, 2 gram-positive rods, and 1 gram-negative rod. Enterococcus faecalis, Enterococcus galli-narum, and Proteus mirabilis were the most frequently observed protease-secreting bacterial species. The presence of proteolytic bacteria in the intestinal tract of poultry in this study suggests the possibility of yet-to-be-described role(s) in cleavage of hemagglutinin that may alter the pathogenicity of avian influenza viruses.

Original languageEnglish (US)
Pages (from-to)1388-1393
Number of pages6
JournalPoultry science
Issue number7
StatePublished - 2009


  • Bacteria
  • Cleavage
  • Hemagglutinin
  • Influenza
  • Protease

ASJC Scopus subject areas

  • Animal Science and Zoology


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