The role of Propionibacterium acnes in and Modic type 1 changes : A literature review

Propionibacterium acnes (P. acnes) is part of the normal flora of human skin, oral cavity, intestinal tract and external ear canal. However, breach in the mucosa as well as ruptured annulus fibrosus provide favorable pathway for P. acnes to nucleus pulposus where it can proliferate under anaerobic condition. In past two decades many authors have identified P. acnes in routine culture of discs. There studies showed that almost 50% of discs cultured were positive for various organism, and in vast majority of culture positive disc, P. acnes was the primary organism isolated. However, there are few studies that refute the hypothesis that P. acnes has a role in pathogenesis of Modic type 1 changes. Identification of P. acnes in culture indicates the infective patho-mechanism in the pathogenesis of Modic type 1 changes, which may be ameable to antibiotic treatment. However, it is still difficult to identify which subset of these patients (patients with low back pain with type 1 Modic change) are infective in nature. Further investigation and more clinical trails will be required for clear identification of the infective subgroup among low back patient in general.