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Mitigating transmission of antimicrobial resistance on large dairy farms by reducing behavioral pathways of exposure


Antibiotics are essential for treatment of bacterial diseases and their use has improved welfare of both humans and animals but benefits of using antibiotics on farms must be balanced against the potential for development and spread of resistance. Reported associations between administration of antimicrobials to dairy cattle and development of resistance are weak but farm workers have frequent contact with cattle and are at high risk of exposure to bacterial pathogens that may harbor resistnace genes. These workers may be an important "entry point" for resistant genes to move from dairy cattle into the human population. Unfortunately, critical control points associated with exposure to pathogens and resistance genes by farm workers are not well understood. Our overarching hypothesis is that risks of transmission of potentially resistant pathogens from dairy cattle to farm workers are dependent on human behavior, and these risks can be reduced by changing farm worker behavior through evidence-based interventions.Work system analysis is an innovative approach used to better understand worker behavior and critical control points associated with transmission of pathogens that may contain resistance genes. Thus, our strategy is to apply a systems engineering approach to identify critical control points for transmission of pathogens and resistance genes that can be modified to reduce risk of exposure. In this project we will use the following aims to identify potential routes of exposure to pathogens that may harbor resistance genes and develop and evaluate interventions that result in decreased risk:Aim 1. Identify farm worker behaviors associated with increased risk of carriage of selected pathogens and resistance genes on farms with varying exposures of cows to antimicrobials. We will define relationships between antimicrobial usage and carriage of selected resistance genes in farm workers and dairy cattle and determine if the risk of carriage varies among farms with different levels of usage.Aim 2. Measure carriage of pathogens and resistance genes in biological specimens collected from farm workers and animals on farms with high and low antimicrobial usage and conduct an epidemiological risk factor analysis of behavioral predictors of carriage of pathogens and resistances genes.Aim 3. Develop, perform & evaluate an intervention to change worker behaviors that are associated with exposure to pathogens and resistance genes. We will design this intervention to be efficient and evidence-based, given the results of Aim 1 and Aim 2.Aim 4. Transfer knowledge to end-users using extension networks and innovative multimedia interactive materials. In so doing, we hope to lower the risk of transmission of pathogens that may harbor resistance genes from dairy cattle to the human population industry-wide.

Ruegg, Pamela
University of Wisconsin - Madison
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