Identification of Plasmid-Mediated Quinolone Resistance in Salmonella Isolated from Swine Ceca and Retail Pork Chops in the United States

Abstract

Fluoroquinolones are important antimicrobial drugs used to treat human <i>Salmonella</i> infections, and resistance is rare in the United States for isolates from human and animal sources. Recently, a number of <i>Salmonella</i> isolates from swine cecal contents and retail pork products from National Antimicrobial Resistance Monitoring System (NARMS) surveillance exhibited decreased susceptibility to ciprofloxacin. We identified two <i>qnrB19</i> quinolone resistance plasmids that are predominantly responsible for this phenomenon and found them distributed among several <i>Salmonella</i> serotypes isolated throughout the United States.