Antimicrobial resistance against critical antibiotics in the environment of intensive and organic Turkey farms

Purpose: The high levels of antimicrobial resistance (AMR) against critical antibiotics in poultry environment are a cause for public health concern for the impact on human health. Intensive rearing conditions for turkeys seem to be associated with increased need for antimicrobial use. As antimicrobial treatments are mostly administered to turkeys via drinking water, we aim to quantify and compare AMR levels in indicator bacteria from turkeys' litter/faeces and drinking water. Methods & Materials: AMR levels in indicator bacteria (E. coli) isolated from litter and from the drinking water pipeline were measured in 28 intensive turkey farms and in 4 organic turkey farms where antimicrobial use is restricted. Subsequently, a selection of 10 farms was categorized in 3 AMR groups: farms with 1) 60% (n = 2) resistance to antibiotics. In all farms, 20 animals were bled for quantification of natural immunity parameters like serum bactericidal activity and lysozyme. Result(s): AMR for a panel of 14 antibiotics was high both in turkey faeces and drinking water, particularly for critical antibiotics, e.g. 80% of isolates was resistant to Ampicillin, Ciprofloxacin and/or Streptomycin. Observed agreement between AMR in water and in litter ranged between 36% and 100% depending on the antibiotics in question. In organic farms, AMR prevalence was lower, but turkeys' immune response was significantly higher (P