(Portland, OR)  --  Multnomah County health officials say two cases of E. coli at a preschool in Portland have been linked to I.M. Healthy SoyNut Butter.  The product is being recalled nationwide after 16 people in nine states, including Oregon, became sickened.  Officials say four people at Montessori of Alameda school have been infected with E. coli, and two other people have shiga-toxin that's producing E. coli.  Health officials are urging parents to keep children home who are vomiting or have diarrhea, and are advising parents to contact their child's doctor with any questions.