Hemorrhagic colitis due to a novel Escherichia coli serotype (O121 : H19) in a transplant patient

Infection due to enterohemorrhagic Escherichia coli (EHEC) has not been des cribed in immunosuppressed patients. We recently saw a case of EHEC infecti on caused by a novel Shiga toxin II-producing Escherichia coli serotype (O1 21:H19) that caused hemorrhagic colitis in a patient with renal and cardiac transplants. The patient's signs, symptoms, and colon pathology were simil ar to reports of EHEC infection in immunocompetent patients. This case sugg ests that the immunosuppressed state may not alter the clinical presentatio n or histopathologic findings of this disorder. Assays for EHEC are not rou tinely done at most hospitals. Therefore, clinicians caring for transplant patients should be aware of the typical clinical presentation of EHEC infec tion, so that they can initiate appropriate laboratory investigation in sus pected cases.