2012 Annual Report 1a.Objectives (from AD-416): Better understanding of the environmental and host factors that influence antibiotic resistance gene transfer and utilize this information to formulate more sustainable ways of using antibiotics in agriculture. 1b.Approach (from AD-416): A green fluorescent protein-tagged derivative of an IncA/C plasmid, developed by the ARS PI, will be utilized to assess the in vivo host range of this plasmid family. This tool will also used to quantitatively assess the effect of antibacterial treatment on the maintenance and spread of this family of plasmids within the fish gut and within fish culture systems. Bacteria which have acquired this plasmid will be identified by virtue of the GFP tag and identified to species by 16S rDNA analysis. 3.Progress Report: This project consists of collaborative research planned for 2012: however, attempts by the cooperator to secure funding for the studies have not been successful. Further planning and efforts to secure funding occurred this year with the goal of conducting the research in 2013.