Cutibacterium (Propionibacterium) acnes is an anaerobic bacteria, a relatively slow growing Gram-positive (stem) bacteria, usually associated with acne skin conditions; it can also cause chronic blepharitis and endophthalmitis, the latter especially after intraocular surgery. The bacterial genome has been sequenced and a study has shown several genes can produce enzymes to reduce skin and proteins that may be immunogenic (activating the immune system).
These bacteria are largely commensal and part of the skin flora is present in the healthiest human adult skin. Usually just barely detectable on preteen skin is healthy. It lives mainly in, among other things, fatty acids in sebum secreted by the sebaceous glands within the follicle. It can also be found throughout the digestive tract in humans and many other animals.
It is named for its ability to produce propionic acid.
Video Propionibacterium acnes
Role in disease
P. acnes bacteria live deep inside the follicles and pores, away from the skin surface. In this follicle, bacteria use sebum, cell debris and metabolic byproducts of surrounding skin tissue as a major source of energy and nutrients. Increased production of sebum by hyperactive sebaceous glands (sebaceous hyperplasia) or follicle blockage can cause bacteria to grow and multiply.
P. acnes bacteria secrete many proteins, including some digestive enzymes. These enzymes are involved in the digestion of sebum and the acquisition of other nutrients. They can also destabilize the cell layers that form the follicle wall. Cellular damage, metabolic byproducts and bacterial remnants produced by rapid growth of P. acne in the follicle may trigger inflammation. This inflammation can cause symptoms associated with some common skin disorders, such as folliculitis and acne vulgaris.
Damage caused by P. acne and associated inflammation makes the affected tissue more susceptible to colonization by opportunistic bacteria, such as Staphylococcus aureus . Preliminary research shows healthy pores are only colonized by P. acne, while unhealthy ones are universally including nonpori-resident Staphylococcus epidermidis , among other bacterial contaminants. Whether this is the root cause, only opportunistic and side effects, or the more complex pathological duality between P. acnes and the Staphylococcus species is unknown.
P. acnes is also found in corneal ulcers, and is a common cause of chronic endophthalmitis after cataract surgery. Rarely, infecting the heart valves leading to endocarditis, and joint infections (septic arthritis) have been reported. Furthermore, Propionibacterium species have been found at the site of ventriculostomy insertion, and subcutaneous areas to the seam sites in patients who have undergone craniotomy. This is a common contaminant in the blood and culture of cerebrospinal fluid.
P. acnes has been found on herniated discs. The secreted propionic acid creates a bone-micro fracture around it. This microbone fracture is 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 can also be found in 23% of controls. The subspecies of P. acnes that cause this infection from sterile tissue (before medical procedures), however, are the same subspecies found on the skin of individuals who do not have acne prone skin, so the possibility of local contaminants. Moderate to severe acne vulgaris appears to be more commonly associated with virulent strains.
P. acne is an opportunistic pathogen, causing various postoperative infections and associated devices, eg, surgery, post-neurosurgical infections, joint prosthesis, shunt, and prosthetic heart valves. Acne can play a role in other conditions, including inflammation of the prostate that causes cancer, SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis), sarcoidosis, and sciatica. It is also thought to be the main source of bacteria from nerve inflammation in the brain of Alzheimer's disease.
Maps Propionibacterium acnes
Antimicrobial susceptibility
P. acnes bacteria are susceptible to various antimicrobial molecules, both from pharmaceutical sources and natural sources. Antibiotics are commonly used to treat infections caused by P. acnes . Acne vulgaris is the disease most often associated with P. acnes infection. The most common antibiotics used to treat acne vulgaris are erythromycin, clindamycin, doxycycline, and minocycline. Some other families of antibiotics are also active against bacteria P. acnes, including quinolones, cephalosporins, pleuromutilin, penicillins, and sulfonamides.
The emergence of bacteria-resistant antibiotics P. acnes is a growing problem worldwide. The problem is felt in North America and Europe. The antibiotic families that are most likely to acquire resistance are macrolides (eg, erythromycin and azithromycin), lincosamides (eg, clindamycin) and tetracyclines (eg, doxycycline and minocycline).
However, P. acnes bacteria are susceptible to many types of antimicrobial chemicals found in over-the-counter antibacterial products, including benzoyl peroxide, triclosan, chloroxylenol (PCMX), and chlorhexidine gluconate.
Some of the naturally occurring molecules and compounds are toxic to bacterial P. acnes. Some essential oils such as rosemary, tea tree oil, clove oil, and orange oil contain antibacterial chemicals.
Elements of silver, sulfur, and copper have also been shown to be toxic to many bacteria, including P. acnes . Natural honey has also been shown to have some antibacterial properties that may be active against P. acnes .
Photosensitivity
P. acnes shines orange when exposed to black light, possibly because of the presence of endogenous porphyrins. These bacteria are killed by ultraviolet light. P. acnes is also very sensitive to light at 405-420 nanometers (near ultraviolet) due to endogenous porphyrin-coporphyrin III. Total irradiance 320 J/cmÃ,² was found to inactivate this bacterium in vitro . This fact is used in phototherapy. The photosensitivity can be increased by pretreatment with aminolevulinic acid, which increases the production of these chemicals, although this causes significant side effects in humans, and in practice is not significantly better than light treatment alone.
Other habitats
Unexpectedly, P. Acnes is found as plant endophytes. In particular, the grapevine appears to host the endophytic population of P. acnes that is closely related to the associated human strains and lines that deviate about 7,000 years ago, at the same time when cropping may have been established. This P. Acnes subtype is dubbed Zappae in honor of Frank Zappa's eccentric composer, to highlight unexpected and unconventional habitats.
References
External links
- Propionibacterium acnes in the US National Library of Medicine Subject Medical Headings (MeSH)
- Propionibacterium (Kenyon College)
- BBC News - "Dangerous skin viruses' against acne"
- Type the strain Propionibacterium acnes in Bac Dive - Metadatabase Bacterial Diversity
Source of the article : Wikipedia
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