Propionibacterium acnes in Human Health and Disease

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. While the association of the Gram-positive anaerobic bac-terium Propionibacterium acnes with the inflammatory skin condition acne vulgaris has been known for over a century, its potential role in other human infections and clinical conditions has undoubtedly been underestimated. This is likely to reflect inadequate anaerobic processingmethods and culture of clinical specimens (>7d incubation), combined with the traditionally held view that P. acnes in a biological sample simply reflects contamination from the resident skin microflora or is clinically irrelevant due to a low level of viru-lence [1]. On such basis, it is likely that an unknown number of P. acnes infections go undiagnosed and unrecognised. In addition, subtle clinical signs and symptoms that are ofte