Isolation of Acanthamoeba from a cerebral abscess.

A 55-year-old diabetic aboriginal woman presented with a two-week history of fever, altered mental state and convulsions. On the basis of computed tomographic scanning a diagnosis of cerebral abscess was made. The pus that was drained produced no bacterial growth but, on microscopy, amoebic cysts were observed. Special cultures produced a growth of Acanthamoeba. The patient appeared to respond to drainage of the abscess and antiprotozoal therapy. Unfortunately, she developed necrotizing enteritis which led ultimately to her death. Antibiotic sensitivity and pathogenicity testing suggest that the Acanthamoeba were unusually virulent. The problems of diagnosis and management are discussed.