watershed, and one was observed in two different goose
samples. Animal and surface water S. Typhimurium PT/PFGE
combination overlap was observed among isolates obtained
from pig feces and water from both the Sumas and Bras
d’Henri rivers, and also among isolates obtained from duck
feces and water from the Grand River. There were also
certain PT/PFGE combinations (e.g., S. Enteritidis PT
13/XAI.0038/BNI.0016; S. Typhimurium PT 108/XAI.0312/
BNI.0022; S. Typhimurium PT 104/XAI.0001/BNI.0018; Table 4)
observed among multiple sampling sites/dates within the
same watershed (data not shown). In general, with the
exception of serovar Enteritidis, there were more unique
PT/PFGE combinations observed among watersheds than
there were overlapping combinations