Enterohemorrhagic Escherichia coli Excretion by Child and Her Cat

To the Editor: Enterohemorrhagic Escherichia coli (EHEC) can cause severe hemorrhagic colitis characterized by gastrointestinal symptoms and bloody diarrhea as well as hemolytic uremic syndrome (1). Cattle and small ruminants are the major natural reservoir of these foodborne pathogens (1,2). Human infections may also develop after direct contact with cows, goats, sheep, and deer (1). Although domestic dogs and cats are known as rare EHEC carriers (3,4), no human EHEC infections associated with pet contact have been reported. Here we report the first case of an EHEC strain infecting both a child and her domestic cat. A 2-year-old girl with bloody diarrhea and vomiting subsequently tested positive for EHEC serotype O145:H–. The isolated strain harbored the path-ogenicity-associated genes stx1, stx2, eae, and hly, as tested by PCR. An enterohemolytic phenotype was also present. After notification of the local health authority, a rigorous search for the possible source of the girl's infection was started. When asked for instances of animal contact, her parents mentioned the family cat, which the girl often handled. The cat is restricted to the house, has no contact with other animals, and is fed only canned catfood. The animal strictly uses a litter box, which is cleaned regularly by the parents. No gastrointesti-nal symptoms in the cat were recorded. Repeated stool samples from the cat grew a strain of EHEC O145:H– that showed the identical pathogenici-ty gene pattern as the girl's isolate. Moreover, a restriction fragment length polymorphism analysis proved the clonal identity of both strains. Because both the girl and the cat continuously excreted the EHEC strain, the cat was assumed to be a possible source of the girl's infection or rein-fection. The cat's infection was treated with probiotics, but the child's EHEC positivity did not change. After 3 months, the girl spontaneously stopped excreting EHEC, while the cat's stool samples remained EHEC positive. The cat was then treated by peroral autovaccination with the heat-inactivated EHEC strain for 10 consecutive days and subsequently stopped shedding EHEC. In the Table, the clinical course and laboratory findings of both girl and cat are summarized. To our knowledge, this case is the first documented of an EHEC strain's affecting both a human and a domestic cat. Both excreted EHEC for ≈3 months. Although the girl had vomiting and diarrhea, the cat was asympto-matic. Several possibilities regarding the infectious process can be noted. First, the girl might have contracted the …