Exploring Pig Finishing Buildings and Broiler Chicken Barns Contribution to Outdoor Airborne Microbiota and Antibiotic-Resistance Genes
JOANIE LEMIEUX, Marc Veillette, Cindy Dumais, Valérie Létourneau, Nathalie Turgeon, Caroline Duchaine, Université Laval
Abstract Number: 150
Working Group: Bioaerosols
Abstract
Introduction. Confined animal feeding operations (CAFOs) are significant emitters of bioaerosols. Indoor air studies are often conducted in CAFOs to quantify, measure exposure or characterize specific air quality markers, mostly from an occupational or an animal health perspective. Bioaerosols can contain microorganisms and antibiotic-resistance genes (ARGs). Through the ventilation systems, a proportion of indoor bioaerosols are disseminated outside the barns where their fate around the buildings vicinity is not well understood.
Objectives. 1) Characterize bacterial and ARGs diversity and 2) quantify specific microbial markers emitted from two conventional pig finishing buildings (PFB) and broiler chicken barns (BCB) within 1km radius from the buildings.
Methods. Bioaerosols were collected using the SASS® 3100 Dry Air Sampler and SASS® 4100 Two-Stage Aerosol Collector. Samples were taken indoor, at the fan exhaust and at four different outdoor locations depending on the prevailing winds: 10m, 100m, 1km downwind and 1km upwind. PFB and BCB were visited three times during the warm season. DNA was extracted from filters and used for performing amplicon-based sequencing to describe bacterial diversity and to quantify by PCR: ARGs, bacterial and archaeal 16S rRNA genes, Enterococcus spp., a phage of Aerococcus viridans and swine and poultry DNA.
Results. Total airborne bacterial biomass (16S rRNA gene) and the other microbial markers decrease with distance from the CAFOs. The same pattern is observed when looking at the sum of all (37) ARGs. At 1km downwind, some markers (Enterococcus spp. and ARGs (erm35)) are still detectable. Bacterial core is similar from indoor to 1km locations. However, relative bacterial abundances exhibit greater dissimilarity at 1km distances compared to the other locations.
Conclusion. Even at 1km downwind, it is possible to detect airborne microbial markers and ARGs likely emitted from CAFOs and recover a similar bacterial core indoors.