FIG. 1.

PFGE fingerprints of 21 S. enterica serovar Muenchen isolates from swine and humans. ^a, two major clusters are shown. The vertical dotted line at 80% genetic similarity was considered an arbitrary threshold for grouping of the clusters into subgroups. Clusters 1 (with four subgroups, subgroups 1-A, 1-B, 1-C, and 1-D) and 2 (with one subgroup, subgroup 2-A) are shown. ^b, origin shows the different regions of North Carolina where the samples originated (NE, northeastern; SE, southeastern; NW, northwestern; SW, southwestern). All the swine isolates originated from the southeastern region of the state, the part of the state where pig production predominates.