Studies on the cytotoxic effects of Propionibacterium acnes strains isolated from cornea

Cutibacterium (Formerly Propionibacterium ) acnes Keratitis: A Review

ABSTRACT

Infectious keratitis is a devastating cause of vision loss worldwide. Cutibacterium acnes ( C. acnes ), a commensal bacterium of the skin and ocular surface, is an underrecognized but important cause of bacterial keratitis. This review presents the most comprehensive and up-to-date information for clinicians regarding the risk factors, incidence, diagnosis, management, and prognosis of C. acnes keratitis (CAK). Risk factors are similar to those of general bacterial keratitis and include contact lens use, past ocular surgery, and trauma. The incidence of CAK may be approximately 10%, ranging from 5% to 25% in growth-positive cultures. Accurate diagnosis requires anaerobic blood agar and a long incubation period (≥7 days). Typical clinical presentation includes small (<2 mm) ulcerations with deep stromal infiltrate causing an anterior chamber cell reaction. Small, peripheral lesions are usually resolved, and patients recover a high visual acuity. Severe infections causing VA of 20/200 or worse are common and often do not significantly improve even after treatment. Vancomycin is considered the most potent antibiotic against CAK, although other antibiotics such as moxifloxacin and ceftazidime are more commonly used as first-line treatment.

In Vitro Antibacterial and Anti-Inflammatory Activity of Arctostaphylos uva-ursi Leaf Extract against Cutibacterium acnes

Cutibacterium acnes (C. acnes) is the main causative agent of acne vulgaris. The study aims to evaluate the antimicrobial activity of a natural product, Arctostaphylos uva-ursi leaf extract, against C. acnes. Preliminary chemical–physical characterization of the extract was carried out by means of FT-IR, TGA and XPS analyses. Skin permeation kinetics of the extract conveyed by a toning lotion was studied in vitro by Franz diffusion cell, monitoring the permeated arbutin (as the target component of the extract) and the total phenols by HPLC and UV-visible spectrophotometry, respectively. Antimicrobial activity and time-killing assays were performed to evaluate the effects of Arctostaphylos uva-ursi leaf extract against planktonic C. acnes. The influence of different Arctostaphylos uva-ursi leaf extract concentrations on the biofilm biomass inhibition and degradation was evaluated by the crystal violet (CV) method. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test was used to determine the viability of immortalized human keratinocytes (HaCaT) after exposure to Arctostaphylos uva-ursi leaf extract for 24 and 48 h. Levels of interleukin (IL)-1β, IL-6, IL-8 and tumour necrosis factor (TNF)-α were quantified after HaCaT cells cotreatment with Arctostaphylos uva-ursi leaf extract and heat-killed C. acnes. The minimum inhibitory concentration (MIC) which exerted a bacteriostatic action on 90% of planktonic C. acnes (MIC₉₀) was 0.6 mg/mL. Furthermore, MIC and sub-MIC concentrations influenced the biofilm formation phases, recording a percentage of inhibition that exceeded 50 and 40% at 0.6 and 0.3 mg/mL. Arctostaphylos uva-ursi leaf extract disrupted biofilm biomass of 57 and 45% at the same concentrations mentioned above. Active Arctostaphylos uva-ursi leaf extract doses did not affect the viability of HaCaT cells. On the other hand, at 1.25 and 0.6 mg/mL, complete inhibition of the secretion of pro-inflammatory cytokines was recorded. Taken together, these results indicate that Arctostaphylos uva-ursi leaf extract could represent a natural product to counter the virulence of C. acnes, representing a new alternative therapeutic option for the treatment of acne vulgaris.

Vertebral osteomyelitis caused by the novel pathogen Cutibacterium modestum: a case report

Background

Cutibacterium modestum is one of the five species of the genus Cutibacterium. While C. acnes has been reported as an important pathogen in bone and joint infections, the clinical characteristics of C. modestum infections remain unclear. Moreover, thus far, there has been no clinical case report regarding C. modestum infections.

Case presentation

An 82-year-old man with a history of repeated trigger point injections for lumbago at the L4 level presented with fever and an exacerbation of lumbago. Physical examination indicated knocking pain at the L4–L5 levels; magnetic resonance imaging showed irregular bone destruction of the L4 vertebral body, and low T1 and high T2 intensity lesions at the L4–L5 intervertebral disc. Two sets of blood cultures (two aerobic and two anaerobic) were performed. Intravenous cefazolin was administered, considering the common pathogens of vertebral osteomyelitis, such as Staphylococcus aureus. The patient’s condition did not improve; thereafter, anaerobic culture bottles revealed Gram-positive rods on day 11 of incubation. There was no evidence of infective endocarditis upon transthoracic echocardiography. Needle aspiration from the L4–L5 intervertebral disc was performed on day 13 that also showed the presence of Gram-positive rods. The patient was diagnosed with vertebral osteomyelitis caused by C. modestum using a combination of characteristic peak analysis with matrix-assisted laser desorption ionization (MALDI), microbial biochemistry examinations, and 16S rRNA gene sequencing from the blood and pus cultures. He was successfully treated with alternative intravenous ampicillin, followed by oral amoxicillin for 10 weeks, according to the tests for ampicillin susceptibility, with a minimum inhibitory concentration of 0.016 μg/mL using E-test® under aerobic conditions.

Conclusions

Cutibacterium modestum is a microorganism that is difficult to identify. A combination of characteristic peaks with MALDI, appropriate microbial biochemical examinations, and 16S rRNA gene sequencing may serve as an efficient guide for the identification of C. modestum.

Propionibacterium acnes Infection in Disc Material and Different Antibiotic Susceptibility in Patients With Lumbar Disc Herniation

Background

Low back pain is an important, worldwide clinical problem from which human populations are suffering. It has been suggested that Propionibacterium acnes is associated with low back pain. The objective of this clinical study is to evaluate the P. acnes infection in the disc material and antibiotic susceptibility in patients with disc herniation.

Methods

A total of 120 patients with disc herniation surgery were enrolled in the study. The samples were excited during discectomy and then cultured in both anaerobic and aerobic incubations. Minimum inhibitory concentration (MIC) was performed for determination of antibiotic susceptibility.

Results

Of 120 samples, 60 (50%) samples were positive for microorganisms. Disc herniation was at the level of L4-L5 in 63 cases and L5-S1 in 57 cases.

Conclusions

According to the results and presence of P. acnes in more than 35% of the cultured samples, the presence of P. acnes in lumbar disc herniation is a suspected element leading to this condition. After analysis of the antibiotics, the lowest MIC value was identified for amoxicillin, ciprofloxacin, erythromycin, rifampicin, tetracycline, vancomycin; the moderate MIC value was for fusidic acid; and the highest MIC value was for gentamicin and trimethoprim.

Development of Rifampicin-Indocyanine Green-Loaded Perfluorocarbon Nanodroplets for Photo-Chemo-Probiotic Antimicrobial Therapy

Acne vulgaris, generally resulted from overgrowth of Propionibacterium acnes (P. acnes), is one of the most difficult-to-treat facial dermatoses and more than 90% of adolescents experienced the disease worldwide. Because the innate non-lymphoid immune system cannot effectively eliminate excessive P. acnes from the skin surface, so far the therapy of acne vulgaris is still mainly dependent on antibiotic treatment. However, long-term or overdose of antibiotics may initiate microbial drug resistance and/or generate unexpected side effects that seriously hamper the use of antibiotics in the clinic. To overcome the aforementioned challenges, the novel rifampicin (RIF)-indocyanine green (ICG)-loaded perfluorocarbon (PFC) nanodroplets (RIPNDs) that may offer combined photo-, chemo-, and probiotic efficacies to P. acnes eradication were developed in this study. The RIPND was first characterized as a sphere-like nanoparticle with surface charge of -20.9 ± 2.40 mV and size of 240.7 ± 6.73 nm, in which the encapsulation efficiencies of RIF and ICG were 54.0 ± 10.5% and 95.0 ± 4.84%, respectively. In comparison to the freely dissolved ICG, the RIPNDs conferred an enhanced thermal stability to the entrapped ICG, and were able to provide a comparable hyperthermia effect and markedly increased production of singlet oxygen under near infrared (NIR; 808 nm, 6 W/cm²) exposure. Furthermore, the RIPNDs were able to induce fermentation of S. epidermidis but not P. acnes, indicating that the RIPNDs may serve as a selective fermentation initiator for the target probiotics. Based on the microbial population index analyses, P. acnes with 1 × 10⁶ cells/mL can be completely eradicated by 12-h co-culture with S. epidermidis fermentation products followed by treatment of RIPNDs (≥20-μM ICG/3.8-μM RIF) + NIR for 5 min, whereby the resulted microbial mortality was even higher than that caused by using 16-fold enhanced amount of loaded RIF alone. Overall these efforts show that the RIPNDs were able to provide improved ICG stability, selective fermentability to S. epidermidis, and enhanced antimicrobial efficacy compared to equal dosage of free RIF and/or ICG, indicating that the developed nanodroplets are highly potential for use in the clinical anti-P. acne treatment with reduced chemotoxicity.

The influence of prostatic Cutibacterium acnes infection on serum levels of IL6 and CXCL8 in prostate cancer patients

Background

Chronic prostatic inflammation, caused by Cutibacterium acnes (C. acnes), has been proposed to influence the risk of prostate cancer development. In vitro studies have demonstrated the capacity of C. acnes to induce secretion of Interleukin 6 (IL6) and C-X-C motif chemokine ligand 8 (CXCL8) by prostate epithelial cells. Both these inflammatory mediators have been implicated in prostate cancer pathophysiology. In this cohort study, we aimed to investigate the influence of prostatic C. acnes on serum levels of IL6 and CXCL8.

Methods

We recruited 99 prostate cancer patients who underwent radical prostatectomy at Örebro University Hospital. The cultivation of pre-operatively obtained prostate biopsies identified C. acnes in 60 of the 99 patients. Levels of IL6 and CXCL8 in pre-operative serum samples were analyzed using ELISA, and concentrations were compared between prostate cancer patients with and without prostatic C. acnes infection using standard statistical methods.

Results

No statistical differences were observed in serum levels of IL6 and CXCL8 between subjects with and without prostatic C. acnes infection.

Conclusions

Our results indicate that prostatic C. acnes infection may give rise to low-grade inflammation with little effect on systemic levels of IL6 and CXCL8.

Clinical Features of Infectious Keratitis Caused by Propionibacterium Acnes

PURPOSE

Propionibacterium acnes is a commensal bacteria whose pathogenicity in infectious keratitis is unclear. In this study, we report infectious keratitis cultured with P. acnes and evaluate its clinical characteristics.

METHODS

All cases of infectious keratitis submitted to the microbiology laboratory of St. Mary's Hospital of Seoul between January 2013 and April 2014 were reviewed. Nonpretreated cases that were positive for P. acnes were identified, and clinical characteristics and treatment outcomes were studied.

RESULTS

Of 132 cultures submitted to the microbiology laboratory, 89 (67.4%) were positive for growth, and a total of 16 (17.9%) of the 89 cases yielded P. acnes in culture medium. Infectious keratitis that was positive for P. acnes was generally small (62.5%) with deep stromal infiltration (81.25%) and a peripheral location (56.25%). The average incubation period was 11.06±5.76 days, and the average time to reepithelialization was 23.50+13.52 days. All the cases of P. acnes evaluated in this report responded well to medical treatment.

CONCLUSIONS

Infectious keratitis with P. acnes is not uncommon and can be confused with other Gram-positive cocci. Thus, P. acnes should be suspected in small-sized keratitis with an unusually long incubation period.

The distribution of infection with Propionibacterium acnes is equal in patients with cervical and lumbar disc herniation

BACKGROUND

Cervical and back pains are important clinical problems affecting human populations globally. It is suggested that Propionibacterium acnes (P. acnes) is associated with disc herniation. The aim of this study is to evaluate the distribution of P. acnes infection in the cervical and lumbar disc material obtained from patients with disc herniation.

METHODS AND MATERIAL

A total of 145 patients with mean age of 45.21 ± 11.24 years who underwent micro-discectomy in cervical and lumbar regions were enrolled into the study. The samples were excited during the operation and then cultured in the anaerobic incubations. The cultured P. acnes were detected by 16S rRNA-based polymerase chain reaction.

RESULTS

In this study, 145 patients including 25 cases with cervical and 120 cases with lumbar disc herniation were enrolled to the study. There was no significant difference in the age of male and female patients (p = 0.123). P. acnes infection was detected in nine patients (36%) with cervical disc herniation and 46 patients (38.3%) with lumbar disc herniation and no significant differences were reported in P. acnes presence according to the disc regions (p = 0.508.). Moreover, there was a significant difference in the presence of P. acnes infection according to the level of lumbar disc herniation (p = 0.028).

CONCLUSION

According to the results, the presence of P. acnes is equal in patients with cervical and lumbar disc herniation. There was a significant difference in the distribution of P. acnes infection according to level of lumbar disc herniation.

LEVEL OF EVIDENCE

II.

Modic changes in the adjacent vertebrae due to disc material infection with Propionibacterium acnes in patients with lumbar disc herniation

INTRODUCTION

Modic changes (MCs) in vertebral bones are induced by two mechanisms of mechanical factors and infection. As Propionibacterium acnes (P. acnes) have been reported to be associated with LBP. The aim of this study is to evaluate the MCs in patients with disc herniation and positive for P. acnes.

METHODS AND MATERIAL

A total of 120 patients with disc herniation surgery were enrolled into the study. The samples were excised during discectomy and then cultured in both anaerobic and aerobic incubations. Gram staining was employed for investigation of all colonies. The cultured P. acnes were detected by 16S rRNA-based polymerase chain reaction (PCR). MCs of baseline MRI were evaluated.

RESULTS

In this study, 120 subjects (69 male and 51 female) with mean age of 43.15 ± 12.62 years were investigated. Sixty disc samples and eight muscle samples were positive for microorganisms. Moreover, 16S rDNA gene was identified in 46 (38.3%) disc samples. Moreover, 36/46 patients with P. acnes in their sample had MCs.

CONCLUSION

According to the results and presence of 36/46 MCs in patients with lumbar disc herniation, positive for P. acnes suggests that P. acnes can lead to edema on the vertebrae endplates near to infected area.

Prosthetic valve endocarditis due to Propionibacterium acnes

OBJECTIVES

To study the characteristics of patients with Propionibacterium acnes prosthetic valve endocarditis (PVE) who required surgery.

METHODS

A single-centre retrospective cohort study was conducted during a 7-year period. Patients with definite infective P. acnes endocarditis, according to the modified Duke criteria, were included. An extended culture protocol was applied. Information on medical health status, surgery, antibiotic treatment and mortality was obtained.

RESULTS

Thirteen patients fulfilled the criteria for P. acnes endocarditis (0.53% of 2466 patients with valve replacement in a 7-year period). All patients were male and had a previous valve replacement. The health status of patients was poor at diagnosis of P. acnes PVE. Most patients (11 of 13, 85%) were admitted with signs of heart failure due to a significant paravalvular leak; 2 of 13 (15%) patients presented with septic emboli. Twelve patients needed redo surgery, whereas one could be treated with antibiotic therapy only. The time between the index surgery and presentation with P. acnes PVE varied between 5 and 135 months (median 26.5 months). Replacement and reconstruction of the dysfunctional valve and affected anatomical structures was mainly performed with a mechanical valve (n = 5, 42%) or a (bio-) Bentall prosthesis (n = 6, 50%). Antibiotic therapy consisted of penicillin with or without rifampicin for 6 weeks after surgery. The mortality in this series was low (n = 1, 8%) and no recurrent endocarditis was found during a median follow-up of 38 months.

CONCLUSIONS

Propionibacterium acnes PVE is a rare complication after valve surgery. Redo surgery is often required. Treatment of the dysfunctional prosthetic aortic valve most often consists of root replacement, in combination with antibiotic therapy.

Taxonomy, Physiology, and Natural Products of Actinobacteria

Actinobacteria are Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla, and they are ubiquitously distributed in both aquatic and terrestrial ecosystems. Many Actinobacteria have a mycelial lifestyle and undergo complex morphological differentiation. They also have an extensive secondary metabolism and produce about two-thirds of all naturally derived antibiotics in current clinical use, as well as many anticancer, anthelmintic, and antifungal compounds. Consequently, these bacteria are of major importance for biotechnology, medicine, and agriculture. Actinobacteria play diverse roles in their associations with various higher organisms, since their members have adopted different lifestyles, and the phylum includes pathogens (notably, species of Corynebacterium, Mycobacterium, Nocardia, Propionibacterium, and Tropheryma), soil inhabitants (e.g., Micromonospora and Streptomyces species), plant commensals (e.g., Frankia spp.), and gastrointestinal commensals (Bifidobacterium spp.). Actinobacteria also play an important role as symbionts and as pathogens in plant-associated microbial communities. This review presents an update on the biology of this important bacterial phylum.

Overview: the role of Propionibacterium acnes in nonpyogenic intervertebral discs

Propionibacterium acnes (P. acnes), an important opportunistic anaerobic Gram-positive bacterium, causes bone and joint infections, discitis and spondylodiscitis. Accumulated evidence suggested that this microbe can colonise inside intervertebral discs without causing symptoms of discitis. Epidemiological investigation shows that the prevalence ranges from 13 % to 44 %. Furthermore, colonisation by P. acnes inside nonpyogenic intervertebral discs is thought to be one pathogen causing sciatica, Modic changes and nonspecific low back pain. Specially, patients can attain significant relief of low back pain, amelioration of Modic changes and alleviation of sciatica after antibiotic therapy, indicating the role of P. acnes in these pathological changes. However, until now, there were hypotheses only to explain problems such as how P. acnes access intervertebral discs and what the exact pathological mechanism it employs during its latent infection period. In addition, research regarding diagnostic procedures and treatment strategies were also rare. Overall, the prevalence and possible pathological role that P. acnes plays inside nonpyogenic intervertebral discs is summarised in this paper.

Management of Propionibacterium acnes infection after shoulder surgery

Propionibacterium acnes (P. acnes) is a gram-positive anaerobic bacillus commonly isolated from the flora of the face, chest, and axilla region. It has emerged as a major pathogen responsible for postoperative shoulder infections after both arthroscopy and arthroplasty procedures. Patients with P. acnes shoulder infection typically present with normal laboratory values (white blood cells (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP)) making diagnosis difficult. Several intraoperative tissue cultures should be obtained and cultured in both agar plate and broth in aerobic and anaerobic conditions for a minimum of 13 days to optimize the sensitivity and specificity to detect P. acnes. The utilization of intraoperative frozen sections to detect P. acnes infection is not reliable. Risk factors include male, cloudy synovial fluid, lucencies around the implant, and periprosthetic membrane formation. Managements include irrigation and debridement, single or two-staged revision, and intravenous antibiotics. Open biopsy prior to the final implantation (two-staged revision) may help detect persistent P. acnes infection. Penicillin and cephalosporins are effective against clinical P. acnes infection and biofilm in vitro. Combination antibiotic therapy with rifampin and daptomycin may further increase the clinical efficacy of treatment.

Propionibacterium acnes: from commensal to opportunistic biofilm-associated implant pathogen

Propionibacterium acnes is known primarily as a skin commensal. However, it can present as an opportunistic pathogen via bacterial seeding to cause invasive infections such as implant-associated infections. These infections have gained more attention due to improved diagnostic procedures, such as sonication of explanted foreign materials and prolonged cultivation time of up to 14 days for periprosthetic biopsy specimens, and improved molecular methods, such as broad-range 16S rRNA gene PCR. Implant-associated infections caused by P. acnes are most often described for shoulder prosthetic joint infections as well as cerebrovascular shunt infections, fibrosis of breast implants, and infections of cardiovascular devices. P. acnes causes disease through a number of virulence factors, such as biofilm formation. P. acnes is highly susceptible to a wide range of antibiotics, including beta-lactams, quinolones, clindamycin, and rifampin, although resistance to clindamycin is increasing. Treatment requires a combination of surgery and a prolonged antibiotic treatment regimen to successfully eliminate the remaining bacteria. Most authors suggest a course of 3 to 6 months of antibiotic treatment, including 2 to 6 weeks of intravenous treatment with a beta-lactam. While recently reported data showed a good efficacy of rifampin against P. acnes biofilms, prospective, randomized, controlled studies are needed to confirm evidence for combination treatment with rifampin, as has been performed for staphylococcal implant-associated infections.

Immunoproteomic Identification of In Vivo-Produced Propionibacterium acnes Proteins in a Rabbit Biofilm Infection Model

Propionibacterium acnes is well-known as a human skin commensal but can also act as an invasive pathogen causing implant-associated infections. In order to resolve these types of P. acnes infections, the implants must be removed, due to the presence of an established biofilm that is recalcitrant to antibiotic therapy. In order to identify those P. acnes proteins produced in vivo during a biofilm infection, we established a rabbit model of implant-associated infection with this pathogen. P. acnes biofilms were anaerobically grown on dextran beads that were then inoculated into the left tibias of rabbits. At 4 weeks postinoculation, P. acnes infection was confirmed by radiograph, histology, culture, and PCR. In vivo-produced and immunogenic P. acnes proteins were detected on Western blot using serum samples from rabbits infected with P. acnes after these bacterial proteins were separated by two-dimensional gel electrophoresis. Those proteins that bound host antibodies were then isolated and identified by tandem mass spectrometry. Radiographs and histology demonstrated a disruption in the normal bone architecture and adherent biofilm communities in those animals with confirmed infections. A total of 24 immunogenic proteins were identified; 13 of these proteins were upregulated in both planktonic and biofilm modes, including an ABC transporter protein. We successfully adapted a rabbit model of implant-associated infection for P. acnes to identify P. acnes proteins produced during a chronic biofilm-mediated infection. Further studies are needed to evaluate the potential of these proteins for either a diagnostic test or a vaccine to prevent biofilm infections caused by P. acnes.

Propionibacterium acnes: an underestimated pathogen in implant-associated infections

The role of Propionibacterium acnes in acne and in a wide range of inflammatory diseases is well established. However, P. acnes is also responsible for infections involving implants. Prolonged aerobic and anaerobic agar cultures for 14 days and broth cultures increase the detection rate. In this paper, we review the pathogenic role of P. acnes in implant-associated infections such as prosthetic joints, cardiac devices, breast implants, intraocular lenses, neurosurgical devices, and spine implants. The management of severe infections caused by P. acnes involves a combination of antimicrobial and surgical treatment (often removal of the device). Intravenous penicillin G and ceftriaxone are the first choice for serious infections, with vancomycin and daptomycin as alternatives, and amoxicillin, rifampicin, clindamycin, tetracycline, and levofloxacin for oral treatment. Sonication of explanted prosthetic material improves the diagnosis of implant-associated infections. Molecular methods may further increase the sensitivity of P. acnes detection. Coating of implants with antimicrobial substances could avoid or limit colonization of the surface and thereby reduce the risk of biofilm formation during severe infections. Our understanding of the role of P. acnes in human diseases will likely continue to increase as new associations and pathogenic mechanisms are discovered.

Comprehensive Analysis of Bacterial Flora in Postoperative Maxillary Cyst Fluid by 16S rRNA Gene and Culture Methods

Intracystic fluid was aseptically collected from 11 patients with postoperative maxillary cyst (POMC), and DNA was extracted from the POMC fluid. Bacterial species were identified by sequencing after cloning of approximately 580 bp of the 16S rRNA gene. Identification of pathogenic bacteria was also performed by culture methods. The phylogenetic identity was determined by sequencing 517–596 bp in each of the 1139 16S rRNA gene clones. A total of 1114 clones were classified while the remaining 25 clones were unclassified. A total of 103 bacterial species belonging to 42 genera were identified in POMC fluid samples by 16S rRNA gene analysis. Species of Prevotella (91%), Neisseria (73%), Fusobacterium (73%), Porphyromonas (73%), and Propionibacterium (73%) were found to be highly prevalent in all patients. Streptococcus mitis (64%), Fusobacterium nucleatum (55%), Propionibacterium acnes (55%), Staphylococcus capitis (55%), and Streptococcus salivarius (55%) were detected in more than 6 of the 11 patients. The results obtained by the culture method were different from those obtained by 16S rRNA gene analysis, but both approaches may be necessary for the identification of pathogens, especially of bacteria that are difficult to detect by culture methods, and the development of rational treatments for patients with POMC.

Propionibacterium acnes: infection beyond the skin

Propionibacterium acnes is a Gram-positive bacterium that forms part of the normal flora of the skin, oral cavity, large intestine, the conjunctiva and the external ear canal. Although primarily recognized for its role in acne, P. acnes is an opportunistic pathogen, causing a range of postoperative and device-related infections. These include infections of the bones and joints, mouth, eye and brain. Device-related infections include those of joint prostheses, shunts and prosthetic heart valves. P. acnes may play a role in other conditions, including inflammation of the prostate leading to cancer, SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome, sarcoidosis and sciatica. If an active role in these conditions is established there are major implications for diagnosis, treatment and protection. Genome sequencing of the organism has provided an insight into the pathogenic potential and virulence of P. acnes.

Granulomatous Propionibacterium acnes infection after trauma surgery

We report here a rare case of infection caused by Propionibacterium acnes following trauma surgery: a 36-year-old male, accident victim was admitted to the hospital because of polytrauma. He underwent a long-drawn-out surgical intervention and after a free-muscle transfer using the rectus femoris muscle, signs of inflammation were detected in the affected area. Microbiological examination of the wound revealed the presence of P. acnes as the only etiological agent of this infection. Adequate antibiotic treatment with penicillin had been started right after the positive microbiological result. Our data confirm the pathogenic potential of P. acnes in late post-surgical infections, and suggest a proper therapeutic approach with intravenous antibiotics and surgical removal of the infected tissue.

Proteomic identification of secreted proteins of Propionibacterium acnes

Background

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.

Results

Culture supernatant proteins of P. acnes were separated by two-dimensional electrophoresis (2-DE) and all Coomassie-stained spots were subsequently identified by MALDI mass spectrometry (MALDI-MS). A set of 20 proteins was secreted in the mid-exponential growth phase by the majority of strains tested. Functional annotation revealed that many of these common proteins possess degrading activities, including glycoside hydrolases with similarities to endoglycoceramidase, β-N-acetylglucosaminidase and muramidase; esterases such as lysophospholipase and triacylglycerol lipase; and several proteases. Other secreted factors included Christie-Atkins-Munch-Petersen (CAMP) factors, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and several hypothetical proteins, a few of which are unique to P. acnes. Strain-specific differences were apparent, mostly in the secretion of putative adhesins, whose genes exhibit variable phase variation-like sequence signatures.

Conclusions

Our proteomic investigations have revealed that the P. acnes secretome harbors several proteins likely to play a role in host-tissue degradation and inflammation. Despite a large overlap between the secretomes of all four P. acnes phylotypes, distinct differences between predicted host-tissue interacting proteins were identified, providing potential insight into the differential virulence properties of P. acnes isolates. Thus, our data presents a rich resource for guiding much-needed investigations on P. acnes virulence factors and host interacting properties.

Optimization of electrotransformation conditions for Propionibacterium acnes

Propionibacterium acnes has been known to be involved in the pathology of acne. However, the definite mechanism in the development of acne and the inflammation are unknown. For P. acnes, a transformation method has not been established, although it is believed to be a basic tool for gene manipulation. This study attempted to develop a P. acnes transformation method by using electroporation. Various parameters were used to develop and optimize the transformation of P. acnes. Among them two factors were crucial in the transformation for P. acnes: one was the E. coli strain from which the plasmid DNA had been isolated and the other the growth temperature of P. acnes-competent cells. It was essential to prepare plasmid DNA from a dam(-) E. coli strain, ET12567. When plasmid DNAs isolated from the other E. coli strains such as JM109 and HB101 were tested, transformation efficiency was extremely low. When P. acnes cells were cultivated at 24 degrees C for competent cell preparation, transformation efficiency increased considerably. When plasmid DNA isolated from a dam(-) mutant strain of E. coli was used for transformation of P. acnes which had been grown at 24 degrees C, maximum transformation efficiency of 1.5 x 10(4) transformants per mug of plasmid DNA was obtained at a field strength of 15 kV/cm with a pulse time of 3.2 ms. This is believed to be the first report on the transformation of P. acnes which can be employed for gene manipulations including knock-out of specific genes.

Genomics of Actinobacteria: tracing the evolutionary history of an ancient phylum

Actinobacteria constitute one of the largest phyla among bacteria and represent gram-positive bacteria with a high G+C content in their DNA. This bacterial group includes microorganisms exhibiting a wide spectrum of morphologies, from coccoid to fragmenting hyphal forms, as well as possessing highly variable physiological and metabolic properties. Furthermore, Actinobacteria members have adopted different lifestyles, and can be pathogens (e.g., Corynebacterium, Mycobacterium, Nocardia, Tropheryma, and Propionibacterium), soil inhabitants (Streptomyces), plant commensals (Leifsonia), or gastrointestinal commensals (Bifidobacterium). The divergence of Actinobacteria from other bacteria is ancient, making it impossible to identify the phylogenetically closest bacterial group to Actinobacteria. Genome sequence analysis has revolutionized every aspect of bacterial biology by enhancing the understanding of the genetics, physiology, and evolutionary development of bacteria. Various actinobacterial genomes have been sequenced, revealing a wide genomic heterogeneity probably as a reflection of their biodiversity. This review provides an account of the recent explosion of actinobacterial genomics data and an attempt to place this in a biological and evolutionary context.

Propionibacterium acnes

Propionibacterium acnes, a common skin organism, is most notably recognized for its role in acne vulgaris. It also causes postoperative and device-related infections and has been associated with a number of other conditions such as sarcoidosis and synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO), although its precise role as a causative agent remains to be determined. Propionibacterium acnes produces a number of virulence factors and is well known for its inflammatory and immunomodulatory properties. Recent publication of the P. acnes genome should provide further insights into the pathogenic capabilities of the organism and potentially lead to the development of new therapies.

Quantification and detection of bacteria from postoperative maxillary cyst by polymerase chain reaction

BACKGROUND/AIMS

Postoperative maxillary cyst (POMC) is known to occur as a delayed complication of radical maxillary sinus surgery, such as Caldwell-Luc surgery. The cyst gradually expands with no symptoms over a period of years, and then occasionally causes swelling and pain in the buccal region and/or the mucogingival fold. It is probable that bacterial infection affects the progression of POMC symptoms. The aims of this study were to determine the bacterial density and to examine the presence of 20 oral bacteria in POMC fluids.

METHODS

POMC fluids (4 purulent, 2 mucous and 4 serous) were sampled from 10 subjects (aged 43-77 years). Bacterial quantification and detection were performed by real-time polymerase chain reaction (PCR) and nested PCR based on bacterial 16S rRNA genes, respectively.

RESULTS

Bacterial DNA was detected in all samples and the average concentrations of bacterial DNA were 5.9 (purulent), 0.5 (mucous), and 0.7 (serous) ng/mg of sample. Twelve bacterial species, including anginosus streptococci, known to be associated with abscess formation, were detected in the purulent fluids, while two and five species were detected in the mucous and serous fluids, respectively.

CONCLUSION

Purulent fluids contained numerous bacteria of various types, thus suggesting that oral bacteria may cause symptoms such as pain in POMC with purulent fluids. Mucous and serous fluids also contained bacteria, although their numbers were small, thus suggesting an association between bacteria and progression of POMC.

Insights in the Pathogenic Potential of Propionibacterium acnes From Its Complete Genome

One of the long-lasting open questions in understanding acne is the role of the skin bacterium Propionibacterium acnes. Opinions within the scientific community diverge regarding the importance of this Gram-positive bacterium not only in acne but also in other P. acnes-associated diseases. The recently decoded genome gives us some clues with respect to its pathogenic potential and its strategies to survive in the harsh environment of human skin. This review focuses on the major findings of the genome sequence. Special attention has been drawn to the cell surface composition of P. acnes, its antigenic potential, and to enzymes that are potentially involved in degrading skin-derived substances.

The Complete Genome Sequence of Propionibacterium Acnes, a Commensal of Human Skin

Propionibacterium acnes is a major inhabitant of adult human skin, where it resides within sebaceous follicles, usually as a harmless commensal although it has been implicated in acne vulgaris formation. The entire genome sequence of this Gram-positive bacterium encodes 2333 putative genes and revealed numerous gene products involved in degrading host molecules, including sialidases, neuraminidases, endoglycoceramidases, lipases, and pore-forming factors. Surface-associated and other immunogenic factors have been identified, which might be involved in triggering acne inflammation and other P. acnes-associated diseases.