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''Propionibacterium acnes'' is the relatively slow-growing, typically aerotolerant anaerobic, Gram-positive bacterium (rod) linked to the skin condition of acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery. The genome of the bacterium has been sequenced and a study has shown several genes can generate enzymes for degrading skin and proteins that may be immunogenic (activating the immune system).〔 〕 This bacterium is largely commensal and part of the skin flora present on most healthy adult humans' skin. It is usually just barely detectable on the skin of healthy preadolescents. It lives primarily on, among other things, fatty acids in sebum secreted by sebaceous glands in the follicles. It may also be found throughout the gastrointestinal tract in humans and many other animals. It is named after its ability to generate propionic acid. ==Role in disease== ''P. acnes'' bacteria live deep within follicles and pores, away from the surface of the skin. In these follicles, ''P. acnes'' bacteria use sebum, cellular debris and metabolic byproducts from the surrounding skin tissue as their primary sources of energy and nutrients. Elevated production of sebum by hyperactive sebaceous glands (sebaceous hyperplasia) or blockage of the follicle can cause ''P. acnes'' bacteria to grow and multiply. ''P. acnes'' bacteria secrete many proteins, including several digestive enzymes. These enzymes are involved in the digestion of sebum and the acquisition of other nutrients. They can also destabilize the layers of cells that form the walls of the follicle. The cellular damage, metabolic byproducts and bacterial debris produced by the rapid growth of ''P. acnes'' in follicles can trigger inflammation. This inflammation can lead to the symptoms associated with some common skin disorders, such as folliculitis and acne vulgaris. The damage caused by ''P. acnes'' and the associated inflammation make the affected tissue more susceptible to colonization by opportunistic bacteria, such as ''Staphylococcus aureus''. Preliminary research shows healthy pores are only colonized by ''P. acnes'', while unhealthy ones universally include the nonpore-resident ''Staphylococcus epidermidis'', amongst other bacterial contaminants. Whether this is a root causality, just opportunistic and a side effect, or a more complex pathological duality between ''P. acnes'' and this particular ''Staphylococcus'' species is not known. ''P. acnes'' has also been found in corneal ulcers, and is a common cause of chronic endophthalmitis following cataract surgery. Rarely, it infects heart valves leading to endocarditis, and infections of joints (septic arthritis) have been reported.〔 Furthermore, ''Propionibacterium'' species have been found in ventriculostomy insertion sites, and areas subcutaneous to suture sites in patients who have undergone craniotomy. It is a common contaminant in blood and cerebrospinal fluid cultures. ''P. acnes'' has been found in herniated discs. The propionic acid which it secretes creates micro-fractures of the surrounding bone. These micro-fractures are sensitive and it has been found that antibiotics have been helpful in resolving this type of low back pain. ''P. acnes'' can be found in bronchoalveolar lavage of approximately 70% of patients with sarcoidosis and is associated with disease activity, but it can be also found in 23% of controls. The subspecies of ''P. acnes'' that cause these infections of otherwise sterile tissues (prior to medical procedures), however, are the same subspecies found on the skin of individuals who do not have acne-prone skin, so are likely local contaminants. Moderate to severe acne vulgaris appears to be more often associated with virulent strains. ''P. acnes'' is an opportunistic pathogen, causing a range of postoperative and device-related infections e.g.,surgery,〔Haidar R., Najjar M., Boghossian A.D., Tabbarah Z., "Propionibacterium acnes causing delayed postoperative spine infection: Review." Scandinavian Journal of Infectious Diseases. 42 (6-7) (pp 405-411), 2010〕 post-neurosurgical infection,〔Nisbet, M. Briggs, S. Ellis-Pegler, R. Thomas, M. Holland, D. "Propionibacterium acnes: an under-appreciated cause of post-neurosurgical infection" Journal of Antimicrobial Chemotherapy. 60(5). NOV 2007. 1097-1103.1103..〕 joint prostheses, shunts and prosthetic heart valves. ''P. acnes'' may play a role in other conditions, including inflammation of the prostate leading to cancer,〔Fassi Fehri L. Mak TN. Laube B. Brinkmann V. Ogilvie LA. Mollenkopf H. Lein M. Schmidt T. Meyer TF. Bruggemann H. Ijmm.,"Prevalence of Propionibacterium acnes in diseased prostates and its inflammatory and transforming activity on prostate epithelial cells." International Journal of Medical Microbiology. 301(1) 69-78, 2011 Jan.〕 SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis) syndrome, sarcoidosis and sciatica.〔Perry A., Lambert P. " Propionibacterium acnes: Infection beyond the skin." Expert Review of Anti-Infective Therapy. 9 (12) (pp 1149-1156), 2011〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Propionibacterium acnes」の詳細全文を読む スポンサード リンク
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