#01-147

Complete

Date Full Report Received

11/24/2003

Date Abstract Report Received

12/19/2006

Investigation

Institution:
Primary Investigator:

Antimicrobial resistance expression at the farm level is proposed to adversely impact human health, though this relationship is poorly understood. This work suggests that prevalence of antimicrobial resistance within farms is determined to varying degrees by factors other than antimicrobic use and is at least partially a function of a particular clone’s ability to survive in a given farm environment. Antimicrobic use may, however, contribute to resistance prevalence as a selective pressure should the particular clone possess resistance traits (genes). Withdrawing antimicrobics from a farm, even over a prolonged time, does not completely eliminate resistance expression, particularly in cases such as Campylobacter where resistance is plasmid mediated. If the objective is to eliminate resistance transfer through the food supply, then this work suggests that strategies are needed to eliminate resistant carrier clones from farms. Further, there is need to determine what other factors drive susceptible clone selection on farms.