Granulomatous amebic encephalitis in a patient with AIDS: Isolation of Acanthamoeba sp group II from brain tissue and successful treatment with sulfadiazine and fluconazole

A patient with AIDS, treated with highly active antiretroviral therapy and trimethoprim-sulfamethoxazole, presented with confusion, a hemifield defect , and a mass lesion in the right occipital lobe, A brain biopsy confirmed g ranulomatous amebic encephalitis (GAE) due to Acanthamoeba castellanii. The patient,vas treated with fluconazole and sulfadiazine, and the lesion was surgically excised. This is the first case of AIDS-associated GAE respondin g favorably to therapy. The existence of a solitary brain lesion, absence o f other sites of infection, and intense cellular response in spite of a ver y low CD4 count conditioned the favorable outcome. We review and discuss th e diagnostic microbiologic options for the laboratory diagnosis of infectio ns due to free-living amebae.