The anaerobic gram-positive bacterium Propionibacterium acnes is a human skin commensal that is occasionally associated with inflammatory diseases. Recent work has indicated that evolutionary distinct lineages of P. acnes play etiologic roles in disease while others are associated with maintenance of skin homeostasis. To shed light on the molecular basis for differential strain properties, we carried out genomic and transcriptomic analysis of distinct P. acnes strains. We sequenced the genome of the P. acnes strain 266, a type I-1a strain. Comparative genome analysis of strain 266 and four other P. acnes strains revealed that overall genome plasticity is relatively low; however, a number of island-like genomic regions, encoding a variety of putative virulence-associated and fitness traits differ between phylotypes, as judged from PCR analysis of a collection of P. acnes strains. Comparative transcriptome analysis of strains KPA171202 (type I-2) and 266 during exponential growth revealed inter-strain differences in gene expression of transport systems and metabolic pathways. In addition, transcript levels of genes encoding possible virulence factors such as dermatan-sulphate adhesin, polyunsaturated fatty acid isomerase, iron acquisition protein HtaA and lipase GehA were upregulated in strain 266. We investigated differential gene expression during exponential and stationary growth phases. Genes encoding components of the energy-conserving respiratory chain as well as secreted and virulence-associated factors were transcribed during the exponential phase, while the stationary growth phase was characterized by upregulation of genes involved in stress responses and amino acid metabolism. Our data highlight the genomic basis for strain diversity and identify, for the first time, the actively transcribed part of the genome, underlining the important role growth status plays in the inflammation-inducing activity of P. acnes. We argue that the disease-causing potential of different P. acnes strains is not only determined by the phylotype-specific genome content but also by variable gene expression.

Objectives. We sought to describe the prevalence of a hyaluronidase gene and hyaluronidase production in 197 clinical isolates of P. acnes; we assessed kinetics of hyaluronidase production in a subset of three isolates. Methods. The hyaluronidase gene was detected using polymerase chain reaction. Hyaluronidase production was detected by growing isolates on BHI agar containing 400 μg/mL hyaluronic acid and 1% albumin and flooding plates with 2 N glacial acetic acid to precipitate unbound hyaluronic acid, with a zone of clearing representing a positive phenotype. Hyaluronidase production kinetics were measured as a function of hyaluronic acid digestion over time in a liquid medium. Results. A hyaluronidase gene and hyaluronidase production were detected in 100 and 97% of P. acnes isolates, respectively. Hyaluronidase production in liquid medium was detectable after 96 hours of growth. Conclusions. Hyaluronidase production is nearly universal among P. acnes isolates. Three days appear to be required for significant hyaluronidase production in a liquid medium. Detection of hyaluronidase in tissue specimens may be a strategy to differentiate P. acnes infection from colonization when P. acnes is isolated from a clinical specimen.

The effect of oxygen on the in vitro propagation of Propionibacterium acnes was investigated under defined culture conditions. This micro-organism is the predominant bacterial resident within the pilosebaceous follicles of sebum-rich areas of human skin. The organism was grown in continuous culture in defined synthetic medium with glucose as the main carbon-energy source at various air saturation concentrations and in the presence and absence of light. Steady state continuous cultures were achieved at very low oxygen tensions in the presence of light, and at higher levels of oxygen when non-illuminated. Culture biomass yields were higher than those of anaerobic cultures. Bacterial cells were inactivated in the presence of light at high oxygen concentrations because of photosensitization reactions involving excess oxygen and microbial porphyrin species.

Many studies have noted an increase in the number of recognized cases of invasive infections due to Propionibacterium acnes, especially after shoulder replacement surgery. The increase in the number of recognized cases of P. acnes, a nonspore-forming, anaerobic, Gram-positive organism, appears due to both an increase in the number of shoulder operations being performed and more specimens being sent for anaerobic cultures. Nevertheless, the optimal surgical and antibiotic management of P. acnes remains controversial.

Sarcoidosis is caused by Th1-type immune responses to unknown agents, and is linked to the infectious agent Propionibacterium acnes. Many strains of P. acnes isolated from sarcoid lesions cause intracellular infection and autophagy may contribute to the pathogenesis of sarcoidosis. We examined whether P. acnes induces autophagy.

Propionibacterium acnes is a Gram-positive bacterium that colonizes various niches of the human body, particularly the sebaceous follicles of the skin. Over the last years a role of this common skin bacterium as an opportunistic pathogen has been explored. Persistence of P. acnes in host tissue has been associated with chronic inflammation and disease development, for example, in prostate pathologies. This study investigated the intracellular fate of P. acnes in macrophages after phagocytosis. In a mouse model of P. acnes-induced chronic prostatic inflammation, the bacterium could be detected in prostate-infiltrating macrophages at 2 weeks postinfection. Further studies performed in the human macrophage cell line THP-1 revealed intracellular survival and persistence of P. acnes but no intracellular replication or escape from the host cell. Confocal analyses of phagosome acidification and maturation were performed. Acidification of P. acnes-containing phagosomes was observed at 6 h postinfection but then lost again, indicative of cytosolic escape of P. acnes or intraphagosomal pH neutralization. No colocalization with the lysosomal markers LAMP1 and cathepsin D was observed, implying that the P. acnes-containing phagosome does not fuse with lysosomes. Our findings give first insights into the intracellular fate of P. acnes; its persistency is likely to be important for the development of P. acnes-associated inflammatory diseases.

Propionibacterium acnes (P. acnes) has been implicated in the progression of acne inflammation. Because current acne medications have various side effects, it is necessary to explore alternative medications possessing anti-inflammatory activity against P. acnes. We investigated the inhibitory effects of polyphyllin I (PPI) on P. acnes-induced inflammation in vitro. In this study, we examined the effects of PPI on the production of inflammatory cytokines in HaCaT keratinocytes treated with heat-killed P. acnes. These treated HaCaT keratinocytes showed increased expression of Toll-like receptor 2 (TLR2) and production of inflammatory cytokines. PPI significantly suppressed the secretion of inflammatory cytokines, including interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α, and the expression of TLR2 in P. acnes-treated cells. Moreover, we studied the influence of PPI on the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in P. acnes-treated keratinocytes. PPI diminished the activation of NF-κB. Phosphorylated p38 levels were markedly increased after treatment with heat-killed P. acnes but were decreased after treatment with PPI, while the effect of PPI on ERK phosphorylation was not significant. Heat-killed P. acnes and PPI did not have any effect on JNK phosphorylation. Furthermore, we confirmed that NF-κB p65 inhibitor (BAY11-7082), p38 MAPK inhibitor (SB203580), and PPI blocked the expression of IL-8 in heat-killed P. acnes-treated cells. These results demonstrated that PPI has potential for development as a treatment for acne inflammation.

The anaerobic Gram-positive bacterium Propionibacterium acnes is a human skin commensal that resides preferentially within sebaceous follicles; however, it also exhibits many traits of an opportunistic pathogen, playing roles in a variety of inflammatory diseases such as acne vulgaris. To date, the underlying disease-causing mechanisms remain ill-defined and knowledge of P. acnes virulence factors remains scarce. Here, we identified proteins secreted during anaerobic cultivation of a range of skin and clinical P. acnes isolates, spanning the four known phylogenetic groups.

Resveratrol (3,5,4'-trihydroxystilbene) is an antioxidant that has multiple biologic effects including antimicrobial properties. Acne vulgaris is a disease of the pilosebaceous unit, characterized by an inflammatory host immune response to the bacteria Propionibacterium acnes (P. acnes). This study sought to determine whether resveratrol may be a potential treatment for acne vulgaris.

Propionibacterium acnes (P. acnes) and Propionibacterium granulosum (P. granulosum) are common skin colonizers that are implicated as possible contributing factors in acne vulgaris development. We have established direct visualization tools for the simultaneous detection of these closely related species with immunofluorescence assay and fluorescence in situ hybridization (FISH). As proof of principle, we were able to distinguish P. acnes and P. granulosum bacteria in multi-species populations in vitro as well as in a mock skin infection model upon labelling with 16S rRNA probes in combinatorial FISH as well as with antibodies. Furthermore, we report the co-localization of P. acnes and P. granulosum in the stratum corneum and hair follicles from patients with acne vulgaris as well as in healthy individuals. Further studies on the spatial distribution of these bacteria in skin structures in various skin disorders are needed.

Bacteriophages have been introduced as living drugs for infectious diseases; thus, they may provide an alternative to conventional acne therapeutics in patients with non-responsive acne.

The human skin surface harbors huge numbers of microbes. The skin microbiota interacts with its host and forms a skin microbiome profile that is specific for each individual. It has been reported that the skin microbiota that is left on an individual's possessions can act as a sort of "fingerprint" and be used for owner identification. However, this approach needs to be improved to take into account any long-term instability of skin microbiota and contamination from nonspecific bacteria. Here, we took advantage of single-nucleotide polymorphisms (SNPs) in the 16S-encoding rRNA gene of Cutibacterium acnes, the most common and abundant bacterium on human skin, to perform owner identification. We first developed a high-throughput genotyping method based on next-generation sequencing to characterize the SNPs of the C. acnes 16S rRNA gene and found that the genotype composition of C. acnes 16S rRNA is individual specific. Owner identification accuracy of around 90% based on random forest machine learning was achieved by using a combination of C. acnes 16S rRNA genotype and skin microbiome profile data. Furthermore, our study showed that the C. acnes 16S rRNA genotype remained more stable over time than the skin microbiome profile. This characteristic of C. acnes was further confirmed by the analysis of publicly available human skin metagenome data. Our approach, with its high precision, good reproducibility, and low costs, thus provides new possibilities in the field of microbiome-based owner identification and forensics in general.IMPORTANCE Cutibacterium acnes is the most common and abundant bacterial species on human skin, and the gene that encodes its 16S rRNA has multiple single-nucleotide polymorphisms. In this study, we developed a method to efficiently determine the C. acnes 16S rRNA genotype composition from microbial samples taken from the hands of participants and from their possessions. Using the C. acnes 16S rRNA genotype composition, we could predict the owner of a possession with around 90% accuracy when the 16S rRNA gene-based microbiome profile was included. We also showed that the C. acnes 16S rRNA genotype composition was more stable over time than the skin microbiome profile and thus is more suitable for owner identification.

Purpose. Low-virulence anaerobic bacteria, especially the Propionibacterium acnes (P. acnes), have been thought to be a new pathogeny for a series of disc diseases. However, until now, there has been no histological evidence to confirm this link. The purpose of this study was to confirm the presence of P. acnes in nonpyogenic intervertebral discs via histological observation. Method. Degenerated intervertebral discs were harvested from 76 patients with low back pain and/or sciatica but without any symptoms of discitis or spondylodiscitis. The samples were cultured under anaerobic conditions and then examined using 16S rDNA PCR to screen for P. acnes. Samples found to be positive for P. acnes were stained with hematoxylin-eosin (HE) and modified Brown-Brenn staining and observed under a microscope. Results. Here, 16 intervertebral discs were found to be positive for P. acnes via 16S rDNA PCR and the prevalence was 21.05% (16/76). Among them, 7 samples had visible microbes stained with HE and modified Brown-Brenn staining. Morphological examination showed the bacteria to be Gram-positive and rod-shaped, so they were considered P. acnes. Conclusion. P. acnes is capable of colonizing some degenerated intervertebral discs without causing discitis, and its presence could be further confirmed by histological evidence. Targeting these bacteria may be a promising therapy method for some disc diseases.

Acne vulgaris is a disease of the pilosebaceous unit characterized by increased sebum production, hyperkeratinization, and immune responses to Propionibacterium acnes (PA). Here, we explore a possible mechanism by which a lipid receptor, G2A, regulates immune responses to a commensal bacterium.

Propionibacterium acnes is a Gram positive rod inhabiting the human skin that also infects orthopaedic implants and is associated with acne vulgaris. Previously, one lytic bacteriophage, PA6, from P. acnes has been sequenced and partially characterized. We recently isolated several inducible phages from P. acnes classified as Siphoviruses based on morphology and partial genome sequencing.

Prosthetic joint infections (PJIs) caused by Propionibacterium acnes account for a larger proportion of the total number of PJIs than previously assumed and thus knowledge of the antimicrobial susceptibility patterns of P. acnes is of great value in everyday clinical practice.

Progressive macular hypomelanosis (PMH) is a skin disorder that is characterized by hypopigmented macules and usually seen in young adults. The skin microbiota, in particular the bacterium Propionibacterium acnes, is suggested to play a role. Here, we compared the P. acnes population of 24 PMH lesions from eight patients with corresponding nonlesional skin of the patients and matching control samples from eight healthy individuals using an unbiased, culture-independent next-generation sequencing approach. We also compared the P. acnes population before and after treatment with a combination of lymecycline and benzoylperoxide. We found an association of one subtype of P. acnes, type III, with PMH. This type was predominant in all PMH lesions (73.9% of reads in average) but only detected as a minor proportion in matching control samples of healthy individuals (14.2% of reads in average). Strikingly, successful PMH treatment is able to alter the composition of the P. acnes population by substantially diminishing the proportion of P. acnes type III. Our study suggests that P. acnes type III may play a role in the formation of PMH. Furthermore, it sheds light on substantial differences in the P. acnes phylotype distribution between the upper and lower back and abdomen in healthy individuals.

Propionibacterium acnes is a commensal of human skin but is also known to be involved in certain diseases, such as acne vulgaris and infections of orthopaedic implants. Treatment of these conditions is complicated by increased resistance to antibiotics and/or biofilm formation of P. acnes bacteria. P. acnes can be infected by bacteriophages, but until recently little has been known about these viruses. The aim of this study was to identify and characterize inducible phages from P. acnes on a genetic and morphological basis.

Propionibacterium acnes (P. acnes) is an anaerobic, Gram-positive bacteria encountered in inflammatory acne lesions, particularly in the pilosebaceous follicle. P. acnes triggers a strong immune response involving keratinocytes, sebocytes and monocytes, the target cells during acne development. Lipoteicoic acid and peptidoglycan induce the inflammatory reaction, but no P. acnes surface protein interacting with Toll-like receptors has been identified. P. acnes surface proteins have been extracted by lithium stripping and shown to induce CXCL8 production by keratinocytes.

Propionibacterium acnes and Staphylococcus epidermidis live in close proximity on human skin, and both bacterial species can be isolated from normal and acne vulgaris-affected skin sites. The antagonistic interactions between the two species are poorly understood, as well as the potential significance of bacterial interferences for the skin microbiota. Here, we performed simultaneous antagonism assays to detect inhibitory activities between multiple isolates of the two species. Selected strains were sequenced to identify the genomic basis of their antimicrobial phenotypes.