Detailed Instructions: In this task, you are given a sentence. You are expected to write the name of the organism substances in the body mentioned in the input. Although there might be several correct answers, you need to write one of them.
Q:  The goal of this study was to determine whether immunosuppression plays a role in the level and duration of fecal shedding of Escherichia coli O157 .
A:
fecal