Antibiotic resistant enterococci and staphylococci isolated from flies collected near confined poultry feeding operations

Jay P. Graham, Lance B. Price, Sean L. Evans, Thaddeus K. Graczyk, Ellen K. Silbergeld

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


Use of antibiotics as feed additives in poultry production has been linked to the presence of antibiotic resistant bacteria in farm workers, consumer poultry products and the environs of confined poultry operations. There are concerns that these resistant bacteria may be transferred to communities near these operations; however, environmental pathways of exposure are not well documented. We assessed the prevalence of antibiotic resistant enterococci and staphylococci in stored poultry litter and flies collected near broiler chicken houses. Drug resistant enterococci and staphylococci were isolated from flies caught near confined poultry feeding operations in the summer of 2006. Susceptibility testing was conducted on isolates using antibiotics selected on the basis of their importance to human medicine and use in poultry production. Resistant isolates were then screened for genetic determinants of antibiotic resistance. A total of 142 enterococcal isolates and 144 staphylococcal isolates from both fly and poultry litter samples were identified. Resistance genes erm(B), erm(A), msr(C), msr(A/B) and mobile genetic elements associated with the conjugative transposon Tn916, were found in isolates recovered from both poultry litter and flies. Erm(B) was the most common resistance gene in enterococci, while erm(A) was the most common in staphylococci. We report that flies collected near broiler poultry operations may be involved in the spread of drug resistant bacteria from these operations and may increase the potential for human exposure to drug resistant bacteria.

Original languageEnglish (US)
Pages (from-to)2701-2710
Number of pages10
JournalScience of the Total Environment
Issue number8
StatePublished - Apr 1 2009


  • Antibiotic resistance
  • Enterococci
  • Flies
  • Poultry litter
  • Staphylococci

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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