Electrophoretic plasmid profiles of representative strains of the Typhimurium ST213 genotype. The diversity of plasmid sizes exhibited by strains carrying or lacking blaCMY-2 is shown. Lanes 1 and 9 show the E. coli reference plasmid pAR060302 , which was used as a 160-kb-size marker and as a positive control in the hybridization experiments. Lane 5 shows the plasmid profile of E. coli strain E2348/69 used as other size marker (100 and 6 kb) and as a negative control in the hybridization experiments. Lanes 2 to 4 display the plasmid profiles of blaCMY-2-positive strains belonging to the IncA/C plasmid type I (see Results): YURES 03-7, YUHS 05-78 and YUHS 03-19, respectively. Lanes 6 and 7 show the plasmid profiles of blaCMY-2-negative strains of plasmid type I: SLRES 02-108 and MIPUS 03-27, respectively, and lane 8 shows the plasmid profile of a representative strain of plasmid type II: SORAPUS 04-29. The IncA/C plasmids are indicated by an asterisk at the right side of the bands.