AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Tracking the Movement of Antibiotic Resistant Genes in Dairy Farms using Computational Fluid Dynamics
HYOUNGMOOK PAK, Maria King, Texas A&M University
Abstract Number: 307 Working Group: Bioaerosols
Abstract The increased use of antibiotics in dairy farms is a major cause of the development and dissemination of antibiotic resistance genes (ARGs). The airborne genes can be transported by the wind and be introduced to various bacterial species via horizontal gene transfer. The spread of multidrug resistance in bacteria poses a serious threat to animal and human health. This is especially relevant to open dairy farms where environmental factors play a significant role. This study examines how computational fluid dynamics (CFD) modeling can be used to create the airflow patterns within the dairy farm and identify the movement of ARGs.
In a dairy farm, which had 36 axial fans for evaporative cooling, a Kirby-Bauer test on different bacterial isolates from twenty manure samples collected along the farm revealed that bacteria located under the first row of fans were more resistant to antibiotics, such as ampicillin, cephalothin, and tetracycline, than those in other areas of the farm. At this area, all the manure accumulated when the floor was flooded for cleaning four times a day. Additionally, this area was shaded at the time of sample collection. A three-dimensional computational fluid dynamics (CFD) simulation of air flow patterns revealed that the area with high antibiotic resistance was not disturbed by the fan-generated air movement. High humidity, low sunlight, and low air movement seem to promote the growth and spread of ARGs, which then can be reintroduced into the dairy farm.
Sequencing the bacterial DNA for each isolate will determine which species carry the antimicrobial resistance genes and experimental air velocity measurements will validate the CFD simulation results.