Figure 2: Phylogroup distribution of P. acnes isolates recovered from excised disc tissue ( ). A total of one or more biopsy specimens recovered from 24/64 patients were positive for growth of P. acnes. Phylogroups were identified using a combination of recA and mAb typing. Five separate nucleus disc tissue samples were surgically removed from each patient as recommended by the IDSA [23]. P = patient number.