Cerebral cyst infection with Micrococcus sedentarius. Case report.

A 7-year-old boy with congenital hydrocephalus and a left septate cerebral cyst presented with a shunt infection due to Micrococcus sedentarius, resistant to all penicillins. The shunt infection was persistent despite several courses of parenteral, intraventricular, and intracyst antibiotics. Evaluation of the ventricular fluid revealed adequate "killing power" against the patient's microorganism. No extracranial focus of infection could be found. Computerized tomographic scanning, along with air ventriculography, identified a noncommunicating area of the cerebral cyst. Only when communication between this location and the rest of the cyst was established were the antibiotics efficacious. Undercirculated areas of cerebrospinal fluid should be sought when shunt infections and ventriculitis persist in spite of adequate parenteral and local therapy in patients with brain cysts.