[Postoperative recurrence of subdural empyema].

We present a case of recurrent subdural post-surgical empyema by Proprionibacterium acnes after a first drained empyema in which no microbiological diagnosis was reached. P. acnes is a gram-positive anaerobic organism which is part of the saprophytic flora of the skin and others parts of the body. However, it can cause infections, as in the central nervous system, especially post-surgical infections in which can be the second more frequent organism after Staphylococcus aureus. P. acnes grows slowly and shows better growth in liquid anaerobic media. It is usually resistant to metronidazol and sensitive to penicillin. In postoperative central nervous system infections we must take into account the possibility of this organism, process the sample properly and keep touch with the Microbiology Department.