Simultaneous cytomegalovirus and Mycobacterium tuberculosis infection presenting as hemorrhagic colitis 3 years after a kidney transplant

Cytomegalovirus is an important cause of colonic disease in solid organ transplant recipients. Although several reports have shown that simultaneous infection with other pathogens may aggravate the course of cytomegalovirus colitis, to our knowledge, no case of colitis caused by simultaneous cytomegalovirus and Mycobacterium tuberculosis has been previously reported. We describe a case of hemorrhagic colitis associated with simultaneous cytomegalovirus/ Mycobacterium tuberculosis infection in a 26-year-old woman, 38 months after a kidney transplant. Initial results of histopathologic analyses of gastrointestinal biopsies showed that tuberculosis was the only cause of colitis, as no morphologic alteration suggestive of cytomegalovirus infection was observed on hematoxylin-eosin staining. However, further analysis with immunoperoxidase staining confirmed the clinical suspicion of cytomegalovirus infection. This report shows that cytomegalovirus/tuberculosis coinfection may be a cause of late-onset colitis among solid organ transplant recipients. It also illustrates that coinfection with other pathogens may pose an additional challenge for diagnosing gastrointestinal cytomegalovirus disease.