Abstract
Coinfections by cytomegalovirus and Clostridioides difficile are rare and can be life-threatening, especially in immunosuppressed patients. Their symptoms often overlap, thus generating a great diagnostic challenge, with the need for multiple diagnostic aids. Under certain conditions, combined antiviral treatment, requiring the addition of foscarnet, is necessary to control cytomegalovirus. The latter drug is relatively safe; however, adverse reactions should always be considered for proper management. We present a case of a patient with a history of Burkitt's lymphoma in complete remission, who received chemotherapy in the past, and currently is living with HIV with undetectable viral load and CD4+ count of 141 cells/mm3, who presented with cytomegalovirus coinfection with suspected resistance to ganciclovir and Clostridioides difficile colitis. The patient required treatment with foscarnet and developed a genital ulcer, secondary to this drug, and therefore it was necessary to suspend it.