PCR amplification of the floR gene (upper panel). Lane M, 100-bp DNA marker (iNtRON Biotechnology, South Korea); lanes 1 to 4, E. coli (03/16; MIC, 16 mg/liter), E. coli (04/18; MIC, 32 mg/liter), Salmonella serovar Enteritidis (03/22; MIC, 32 mg/liter), and K. pneumoniae (04/22; MIC, 32 mg/liter); lane N, negative control; lanes 5 to 10, E. coli (04/1; MIC, 16 mg/liter), Salmonella serovar Typhimurium (04/13; MIC, 16 mg/liter), Salmonella serovar Enteritidis (04/8; MIC, 32 mg/liter), E. coli (03/17; MIC, 16 mg/liter), E. coli (04/19; MIC, 32 mg/liter), and K. pneumoniae (04/21; MIC, 64 mg/liter). Identity confirmation of floR gene in these isolates was performed based on the size and Southern blot hybridization of PCR products (lower panel).