Figure 1. Agarose (1.5%) gel electrophoresis in 1x TAE buffer containing 0.5 µg/ml ethidium bromide. Purified genomic DNA was used as the template in a PCR reaction with the primers Int 1 F 5'-GGC ATC CAA GCA CGA AG-3' and Int 1 B 5'-AAG CAG ACT TGA CCT GA-3' (12). Lane M contains an equal mixture of molecular weight markers grades III and V (Boehringer Mannheim, Germany), Lane N is the negative containing all reaction components with the exception of template DNA, Lane 1, Campylobacter coli CIT-H 6 (IP-I); Lane 2, Salmonella Typhimurium DT104 CIT-F 100 (IP-C). As in A above except that the primers used were qacEΔ1 F 5'-AT GCA ATA GTT GGC GAA GT-3'and qacEΔ1 B 5'-CAA GCT TTT GCC CAT GAA GC-3' (13). As in A above using primers sul1 F 5'-CTT CGA TGA GAG CCG GCG GC-3' and sul1 B 5'-GCA AGG CGG AAA CCC GCG CC-3' (13).