Stool for bacterial culture and enterohemorrhagic E coli Shiga toxin by EIA should be submitted in the C&S transport vial. Only a thumbnail-size portion of stool, about 1 g or 1 mL, should be added to the vial. Overfilling the vial will reduce recovery of stool pathogens. Specimens from sources, such as genital, stool, urine, and upper and