Skip to main content
ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Egg and Poultry Production Safety Research Unit » Research » Publications at this Location » Publication #327715
Research Project: Reduction of Invasive Salmonella enterica in Poultry through Genomics, Phenomics and Field Investigations of Small Multi-Species Farm Environments

Location: Egg and Poultry Production Safety Research Unit

Title: ANTIMICROBIAL SENSITIVITY PATTERNS OF MAJOR ZOONOTIC PATHOGENS FROM A SEASON-LONG “FARM-TO-FORK” STUDY OF ALL NATURAL, ANTIBIOTIC-FREE, PASTURE-RAISED BROILER FLOCKS IN THE SOUTHEASTERN UNITED STATES

Author
item Rothrock, Michael
item Hiett, Kelli
item Guard, Jean
item Jackson, Charlene

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2016
Publication Date: 8/2/2016
Citation: Rothrock Jr, M.J., Hiett, K.L., Guard, J.Y., Jackson, C.R. 2016. ANTIMICROBIAL SENSITIVITY PATTERNS OF MAJOR ZOONOTIC PATHOGENS FROM A SEASON-LONG “FARM-TO-FORK” STUDY OF ALL NATURAL, ANTIBIOTIC-FREE, PASTURE-RAISED BROILER FLOCKS IN THE SOUTHEASTERN UNITED STATES. International Association for Food Protection. St. Louis, Mo, July 31-Aug 3, 2016. p. 3-168.

Interpretive Summary: Introduction: The prevalence of antibiotic resistance microorganisms has significant implications for environmental, animal, and human health. One focus is the use of antibiotics in animal agriculture and its effects on antibiotic resistant bacterial populations within those systems, but before this causal effect can be elucidated, a greater understanding of the background/reference levels of antibiotic resistance devoid of antibiotic use is needed. Purpose: What are the antibiotic resistance profiles of bacteria in agricultural production environments when antibiotics are not used for production purposes? All-natural, pasture-raised production systems where antibiotics are not used nor have been used historically should allow us to better determine background levels of antibiotic resistance in relevant bacteria associated with broiler chicken production. Methods: 15 all-natural, pasture-raised broiler flocks were sampled along the entire “farm-to-fork” continuum, including fecal and soil samples during grow-out, cecal content and carcass rinses during processing, and carcass rinses of the final products delivered to the consumer. Traditional culture methods were used to isolate 3 zoonotic bacterial pathogens (Salmonella, Campylobacter, and Listeria) and generic Escherichia coli and their resistance profiles were determined using the CDC’s NARMS protocol. Results: Sensitivities to a variety of antibiotics were found for not only generic E. coli isolates, but also for the three zoonotic bacterial pathogens, from various points along the “farm-to-fork” continuum. AST profiles did not appear to be dependent on species/serotype of each pathogen, nor where along the “farm-to-fork” continuum the pathogen was isolated. Significance: While not surprising, these results show that background levels for resistance in these production systems need to be considered when determining the causal effect of antibiotic use within the production animals to the proliferation of antibiotic resistance organisms.

Technical Abstract: Introduction: The prevalence of antibiotic resistance microorganisms has significant implications for environmental, animal, and human health. One focus is the use of antibiotics in animal agriculture and its effects on antibiotic resistant bacterial populations within those systems, but before this causal effect can be elucidated, a greater understanding of the background/reference levels of antibiotic resistance devoid of antibiotic use is needed. Purpose: What are the antibiotic resistance profiles of bacteria in agricultural production environments when antibiotics are not used for production purposes? All-natural, pasture-raised production systems where antibiotics are not used nor have been used historically should allow us to better determine background levels of antibiotic resistance in relevant bacteria associated with broiler chicken production. Methods: 15 all-natural, pasture-raised broiler flocks were sampled along the entire “farm-to-fork” continuum, including fecal and soil samples during grow-out, cecal content and carcass rinses during processing, and carcass rinses of the final products delivered to the consumer. Traditional culture methods were used to isolate 3 zoonotic bacterial pathogens (Salmonella, Campylobacter, and Listeria) and generic Escherichia coli and their resistance profiles were determined using the CDC’s NARMS protocol. Results: Sensitivities to a variety of antibiotics were found for not only generic E. coli isolates, but also for the three zoonotic bacterial pathogens, from various points along the “farm-to-fork” continuum. AST profiles did not appear to be dependent on species/serotype of each pathogen, nor where along the “farm-to-fork” continuum the pathogen was isolated. Significance: While not surprising, these results show that background levels for resistance in these production systems need to be considered when determining the causal effect of antibiotic use within the production animals to the proliferation of antibiotic resistance organisms.