title: Potentially pathogenic bacteria and antimicrobial resistance in bioaerosols from cage-housed and floor-housed poultry operations.
abstract: BACKGROUND
  Antibiotics are used in animal confinement buildings, such as cage-housed (CH) and floor-housed (FH) poultry operations, to lower the likeliness of disease transmission. In FH facilities, antibiotics may also be used at sub-therapeutic levels for growth promotion. Low levels of antibiotic create a selective pressure toward antimicrobial resistance (AMR) in chicken fecal bacteria.
  
  
  OBJECTIVE
  The objective of this study was to compare bacteria and AMR genes in bioaerosols from CH and FH poultry facilities.
  
  
  METHODS
  Bioaerosols were collected from 15 CH and 15 FH poultry operations, using stationary area samplers as well as personal sampling devices. Bacteria concentrations were determined by genus- or species-specific quantitative polymerase chain reaction (PCR) and AMR genes were detected using endpoint PCR.
  
  
  RESULTS
  Enterococcus spp., Escherichia coli, and Staphylococcus spp. were significantly higher in bioaerosols of FH poultry operations than CH bioaerosols (P < 0.001) while Clostridium perfringens was significantly higher in area bioaerosols of CH operations than FH area bioaerosols (P < 0.05). Campylobacter spp. were detected only in bioaerosols of FH facilities. Zinc bacitracin resistance gene, bcrR, erythromycin resistance gene, ermA, and tetracycline resistance gene, tetA/C, were more prevalent in bioaerosols of FH facilities than CH bioaerosols (P < 0.01, P < 0.01, and P < 0.05, respectively).
  
  
  CONCLUSIONS
  Most bacteria are more concentrated and most AMR genes are more prevalent in bioaerosols of FH poultry operations, where growth-promoting antibiotics may be used.
authors.affiliation: Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Natasha A
authors.initials: NA
authors.lastname: Just
authors.forename: Valérie
authors.initials: V
authors.lastname: Létourneau
authors.forename: Shelley P
authors.initials: SP
authors.lastname: Kirychuk
authors.forename: Baljit
authors.initials: B
authors.lastname: Singh
authors.forename: Caroline
authors.initials: C
authors.lastname: Duchaine
mesh_terms: D000336:Aerosols; D000391:Air Microbiology; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D006799:Housing, Animal; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D011200:Poultry / Q000382:microbiology*
chemical_list: D000336:Aerosols; D000900:Anti-Bacterial Agents