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Abstract
Antibiotics are used in commercial agriculture not only for treatment of diseases, but also as animal growth promoters. While antibiotics are not used on every farm, resistance is occasionally found on farms that do not have a history of antibiotics use. While resistance can occur due to chromosomal point mutations, it is the acquisition of resistance through horizontal transfer that concerns many scientists. In the complex ecosystems that result from modern agricultural practices, there are many opportunities for food borne bacterial pathogens to acquire antibiotic resistance, and then enter the food chain. In the studies outlined here, we introduce the topic of horizontal antimicrobial transfer and acquisition through a novel gene transfer system: the integron. Next, we examine first the environment of a commercial broiler farm. We examine the various bacterial species that are harboring resistance, to which antibiotics they are resistant, and potential environmental reservoirs of resistance. Finally, we examine to what extent does antibiotic resistance occur in a free-ranging avian species that is not subjected to antibiotic selection pressure.