Focal intracranial infections due to Propionibacterium acnes: Report of three cases

Objective and importance: Except for its role in shunt infections, Propioni bacterium acnes has been of little interest to neurosurgeons. The rarity an d indolent nature of focal intracranial infections by P. acnes limit their recognition. Three cases of serious intracranial infection due to this orga nism are described. Clincal presentation: Three patients with histories of immunosuppression an d neurosurgical procedures developed nonspecific, delayed presentations (5 wk to 5 yr after surgery) of intracranial infections. in two patients, radi ological investigations showed enhancing lesions that were later found to b e brain abscesses. A subdural empyema was found in the third patient. Intervention: All three patients underwent surgical drainage of the purulen t collections. P. acnes was isolated in each case, and each patient was tre ated with a 6-week course of intravenous penicillin. All three patients mad e good recoveries, and subsequent imaging showed no recurrence of the infec tious collections. Conclusion: P. acnes is an indolent organism that may rarely cause severe i ntracranial infections. This organism should be suspected when an intracran ial purulent collection is discovered in a patient with a history of neuros urgical procedures. Immunosuppressed patients may be susceptible to this ot herwise benign organism. Surgical drainage and treatment with intravenous p enicillin should be considered standard therapy.