PEG-8 Laurate Fermentation of Staphylococcus epidermidis Reduces the Required Dose of Clindamycin Against Cutibacterium acnes

The probiotic activity of skin Staphylococcus epidermidis (S. epidermidis) bacteria can elicit diverse biological functions via the fermentation of various carbon sources. Here, we found that polyethylene glycol (PEG)-8 Laurate, a carbon-rich molecule, can selectively induce the fermentation of S. epidermidis, not Cutibacterium acnes (C. acnes), a bacterium associated with acne vulgaris. The PEG-8 Laurate fermentation of S. epidermidis remarkably diminished the growth of C. acnes and the C. acnes-induced production of pro-inflammatory macrophage-inflammatory protein 2 (MIP-2) cytokines in mice. Fermentation media enhanced the anti-C. acnes activity of a low dose (0.1%) clindamycin, a prescription antibiotic commonly used to treat acne vulgaris, in terms of the suppression of C. acnes colonization and MIP-2 production. Furthermore, PEG-8 Laurate fermentation of S. epidermidis boosted the activity of 0.1% clindamycin to reduce the sizes of C. acnes colonies. Our results demonstrated, for the first time, that the PEG-8 Laurate fermentation of S. epidermidis displayed the adjuvant effect on promoting the efficacy of low-dose clindamycin against C. acnes. Targeting C. acnes by lowering the required doses of antibiotics may avoid the risk of creating drug-resistant C. acnes and maintain the bacterial homeostasis in the skin microbiome, leading to a novel modality for the antibiotic treatment of acne vulgaris.

Suppression of Propionibacterium acnes-Induced Skin Inflammation by Laurus nobilis Extract and Its Major Constituent Eucalyptol

Acne is an inflammatory skin disorder in puberty with symptoms including papules, folliculitis, and nodules. Propionibacterium acnes (P. acnes) is the main anaerobic bacteria that cause acne. It is known to proliferate within sebum-blocked skin hair follicles. P. acnes activates monocytic cell immune responses to induce the expression of proinflammatory cytokines. Although the anti-inflammatory function of the Laurus nobilis (L. nobilis) extract (LNE) on several immunological disorders have been reported, the effect of LNE in P. acnes-mediated skin inflammation has not yet been explored. In the present study, we examined the ability of the LNE to modulate the P. acnes-induced inflammatory signaling pathway, and evaluated its mechanism. LNE significantly suppressed the expression of P. acnes-mediated proinflammatory cytokines, such as IL-1β, IL-6, and NLRP3. We also found that LNE inhibited the inflammatory transcription factor NF-κB in response to P. acnes. In addition, eucalyptol, which is the main constituent of LNE, consistently inhibited P. acnes-induced inflammatory signaling pathways. Moreover, LNE significantly ameliorated P. acnes-induced inflammation in a mouse model of acne. We suggest for the first time that LNE hold therapeutic value for the improvement of P. acnes-induced skin inflammation.

Kaempferia parviflora Extract as a Potential Anti-Acne Agent with Anti-Inflammatory, Sebostatic and Anti-Propionibacterium acnes Activity

Kaempferia parviflora, referred to as black ginger, has traditionally been used as a health-promoting alternative medicine. In this study, we examined the anti-inflammatory, sebostatic, and anti-Propionibacterium acnes activities of K. parviflora extract. The extract significantly down-regulated the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), and pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) level. Moreover, the phosphorylation of IĸBα and nuclear factor-kappa B (NF-κB), and the enhanced nuclear translocation of NF-κB p65 in lipopolysaccharide-stimulated murine macrophage-like cell line (RAW 264.7) cells were markedly decreased by the extract. Notably, the main component of K. parviflora, 5,7-dimethoxyflavone, also modulated the expression of iNOS and NF-κB signal molecules in P. acnes-stimulated human keratinocyte (HaCaT) cells. Additionally, K. parviflora extract inhibited the lipogenesis of sebocytes, as evidenced by a reduced level of triglyceride and lipid accumulation in the sebocytes. The sebostatic effect was also confirmed by a reduced expression of peroxisome proliferation-activating receptors (PPAR-γ) and oil-red O staining in sebocytes. Taken together, this study suggests for the first time that K. parviflora extract could be developed as a potential natural anti-acne agent with anti-inflammatory, sebostatic, and anti-P. acnes activity.

pH and Acne

Acne is based on a complex, multifactorial pathophysiology beginning with a microcomedo. Comedogenesis involves follicular hyperproliferation and disturbed keratinization, hyperseborrhea and hyperplasia of sebaceous glands as well as disturbances in skin microbiome. Acne is treated with antibiotics, retinoids, keratolytics, hormonal and anti-inflammatory agents. Efficacy and side effects of given medications are well known. The uppermost layer of the stratum corneum is acidic. The low pH provides protection by slowing down the growth of some bacteria. Increase of skin surface pH leads to impaired barrier function, disturbances in skin microbiome and inflammation. Acne-predisposed skin is in a constant state of subclinical inflammation. Subclinical inflammation may be linked to changes in skin surface pH and disturbances of the stratum corneum, allowing microorganisms to stimulate the production of pro-inflammatory cytokines. Here, based on the current literature, the possible link between the skin surface pH, epidermal barrier function and acne is reviewed.

Propionibacterium acnes Abundance Correlates Inversely with Staphylococcus aureus: Data from Atopic Dermatitis Skin Microbiome

The microbiome may influence disease severity in atopic dermatitis. The skin of atopic dermatitis patients and healthy individuals was sampled in a standardized manner and the microbial composition analysed using next-generation sequencing. Optical density measurements were used to investigate bacterial growth under defined conditions in vitro. Lesional skin from patients with atopic dermatitis had a higher abundance of Staphylococcus aureus and reduced quantities of Propionibacterium acnes and Lawsonella clevelandensis compared with non-lesional skin. The abundance of P. acnes correlated negatively with that of S. aureus (ρ= -0.6501, p < 0.0001). Fermentation products of P. acnes inhibited the growth of S. aureus and S. epidermidis. Serum from patients with atopic dermatitis inhibited the growth of S. aureus to a greater extent than did serum from healthy individuals. These results suggest that selective modification of the skin microbiome could potentially be used as a therapeutic strategy in atopic dermatitis.

Characterization of a Propionibacterium acnes Surface Protein as a Fibrinogen-Binding Protein

Propionibacterium acnes (P. acnes) is a major skin-associated bacterium that was long considered commensal, until several studies revealed it to be an opportunistic pathogen. We investigated the ability of P. acnes surface proteins to recognize ECM proteins and showed that a 58 kDa P. acnes surface protein was specifically recognized by human fibrinogen (hFg). The 58 kDa protein was further characterized by two-dimensional (2-D) electrophoresis and MALDI-ToF as a P. acnes host cell-surface attachment protein, PA25957, recognizing dermatan sulfate (DsA1). This protein sequence contains 432 amino acids with the presence of three structurally different domains: an N-terminal signal peptide, a C-terminal LPXTG motif, and a PT repeat region. DsA1 is mostly produced during stationary phase. It appears to be highly glycosylated, containing GalNAc residues. Purified DsA1 strongly recognizes the Aα and Bβ subunits of hFg, and specific enzymatic deglycosylation of hFg demonstrated the involvement of the protein backbone in the recognition process. The Bβ subunit of hFg was cloned in four peptide fractions (Fg1-Fg4). The N-terminal Fg1 peptide of hFg was recognized by DsA1, and priming DsA1 with Fg1 inhibited DsA1/hFg recognition. We describe here for the first time, the characterization of a P. acnes surface glycoprotein recognizing human fibrinogen.

Multiple Activities of Punica granatum Linne against Acne Vulgaris

Acne is a common skin condition with sebum overproduction, hyperkeratosis, Propionibacterium acnes (P. acnes) and Staphylococcus aureus, and inflammation. Punica granatum (pomegranate) is well-known for its anti-inflammatory effects; however, few studies have discussed the anti-acne effects of pomegranate. In this study, we found that pomegranate extract (PG-E) significantly reduced P. acnes-induced edema in Wistar rat ears. Therefore, an evaluation platform using multiple pathogenic mechanisms of acne was established to explore the anti-acne effects of pomegranate. Results showed that PG-E inhibited bacterial growth and lipase activity. Through a bioguided-fractionation-isolation system, four hydrolysable tannins, punicalagin (1), punicalin (2), strictinin A (3), and granatin B (4), were isolated. Compounds 1 and 2 had greater anti-bacterial activities and anti-testosterone-induced HaCaT proliferative effects than the others. Compounds 1, 3, and 4 displayed lipase inhibitory effects. Compound 4 decreased cyclooxygenase-2 expression and downregulated prostaglandin E₂ production in heat-killed P. acnes-treated RAW 246.7 cells. In conclusion, PG-E is abundant in hydrolysable tannins that display multiple anti-acne capacities, including anti-bacterial, anti-lipase, anti-keratinocyte proliferation, and anti-inflammatory actions. Hence, PG-E has great potential in the application of anti-acne and skin-care products, and punicalagin (1), the most effective component in PG-E, can be employed as a quality control marker.

A Precision Microbiome Approach Using Sucrose for Selective Augmentation of Staphylococcus epidermidis Fermentation against Propionibacterium acnes

Acne dysbiosis happens when there is a microbial imbalance of the over-growth of Propionibacterium acnes (P. acnes) in the acne microbiome. In our previous study, we demonstrated that Staphylococcus epidermidis (S. epidermidis, a probiotic skin bacterium) can exploit glycerol fermentation to produce short-chain fatty acids (SCFAs) which have antimicrobial activities to suppress the growth of P. acnes. Unlike glycerol, sucrose is chosen here as a selective fermentation initiator (SFI) that can specifically intensify the fermentation activity of S. epidermidis, but not P. acnes. A co-culture of P. acnes and fermenting S. epidermidis in the presence of sucrose significantly led to a reduction in the growth of P. acnes. The reduction was abolished when P. acnes was co-cultured with non-fermenting S. epidermidis. Results from nuclear magnetic resonance (NMR) analysis revealed four SCFAs (acetic acid, butyric acid, lactic acid, and succinic acid) were detectable in the media of S. epidermidis sucrose fermentation. To validate the interference of S. epidermidis sucrose fermentation with P. acnes, mouse ears were injected with both P. acnes and S. epidermidis plus sucrose or phosphate buffered saline (PBS). The level of macrophage-inflammatory protein-2 (MIP-2) and the number of P. acnes in ears injected with two bacteria plus sucrose were considerably lower than those in ears injected with two bacteria plus PBS. Our results demonstrate a precision microbiome approach by using sucrose as a SFI for S. epidermidis, holding future potential as a novel modality to equilibrate dysbiotic acne.

An In vitro Model for Bacterial Growth on Human Stratum Corneum

The diversity and dynamics of the skin microbiome in health and disease have been studied recently, but adequate model systems to study skin microbiotas in vitro are largely lacking. We developed an in vitro system that mimics human stratum corneum, using human callus as substrate and nutrient source for bacterial growth. The growth of several commensal and pathogenic bacterial strains was measured for up to one week by counting colony-forming units or by quantitative PCR with strain-specific primers. Human skin pathogens were found to survive amidst a minimal microbiome consisting of 2 major skin commensals: Staphylococcus epidermidis and Propionibacterium acnes. In addition, complete microbiomes, taken from the backs of healthy volunteers, were inoculated and maintained using this system. This model may enable the modulation of skin microbiomes in vitro and allow testing of pathogens, biological agents and antibiotics in a medium-throughput format.

Incidence of Propionibacterium acnes in initially culture-negative thioglycollate broths-a prospective cohort study at a Danish University Hospital

The aim of this study was to prospectively investigate the incidence of Propionibacterium acnes in thioglycollate broths reported as culture-negative at the Department of Clinical Microbiology, Rigshospitalet, to evaluate whether 5 days of incubation was enough to find all relevant cases. Five hundred thioglycollate broths reported as culture-negative after 5 days were consecutively collected and incubated for at least a further 9 days (at least 14 days of incubation in total). Only tissue samples from sterile sites of the body (n = 298), bone tissue (n = 197) and foreign material (n = 5) were included in this study. Samples were divided into two groups: infected group and control group. This made it possible to compare findings between groups, thereby making it possible to estimate the level of true-positive findings and contamination. Samples from 296 participants were included in this study. After exclusion criteria were met, P. acnes was cultured from ten out of 151 patients (6.6%) in the infected group and from one out of 138 participants (0.7%) in the control group. This resulted in more findings of P. acnes in the infected group on day 14 than on day 5 (p 0.002). Furthermore, P. acnes was cultured more often from bone tissue and tissue surrounding foreign materials on day 14 than on day 5 (p 0.04). Clinical microbiology laboratories should consider incubating thioglycollate broths for at least 14 days to find all relevant cases of P. acnes, especially when it comes to bone tissue and tissue surrounding foreign materials.

The Formulation of Bacteriophage in a Semi Solid Preparation for Control of Propionibacterium acnes Growth

AIMS

To isolate and characterise phage which could lyse P. acnes and to formulate the phage into a delivery form for potential application in topical treatment of acne infection.

METHODS AND RESULTS

Using standard phage isolation techniques, ten phage capable of lysing P. acnes were isolated from human skin microflora. Their genomes showed high homology to previously reported P. acnes phage. These phage were formulated into cetomacrogol cream aqueous at a concentration of 2.5x108 PFU per gram, and shown to lyse underlying P. acnes cells grown as lawn cultures. These phage formulations remained active for at least 90 days when stored at four degrees Celsius in a light protected container.

CONCLUSIONS

P. acnes phage formulated into cetomacrogol cream aqueous will lyse surrounding and underlying P. acnes bacteria, and are effective for at least 90 days if stored appropriately.

SIGNIFICANCE AND IMPACT OF THE STUDY

There are few reports of phage formulation into semi solid preparations for application as phage therapy. The formulation method described here could potentially be applied topically to treat human acne infections. The potential exists for this model to be extended to other phage applied to treat other bacterial skin infections.

Propionic Acid Produced by Propionibacterium acnes Strains Contri-butes to Their Pathogenicity

Propionibacterium acnes is an important member of the skin microbiome. The bacterium can initiate signalling events and changes in cellular properties in keratinocytes. The aim of this study was to analyse the effect of the bacterium on an immortalized human keratinocyte cell line. The results show that various P. acnes strains affect the cell-growth properties of these cells differentially, inducing cytotoxicity in a strain-specific and dose-dependent manner. We propose that bacterially secreted propionic acid may contribute to the cytotoxic effect. This acid has a role in maintaining skin pH and exhibits antimicrobial properties, but may also have deleterious effects when the local concentration rises due to excessive bacterial growth and metabolism. These results, together with available data from the literature, may provide insight into the dual role of P. acnes in healthy skin and during pathogenic conditions, as well as the key molecules involved in these functions.

Reduced expression of dermcidin, a peptide active against propionibacterium acnes, in sweat of patients with acne vulgaris

Dermcidin (DCD), an antimicrobial peptide with a broad spectrum of activity against bacteria such as Propionibacterum acnes, is expressed constitutively in sweat in the absence of stimulation due to injury or inflammation. The aim of this study was to determine the relationship between DCD expression and acne vulgaris associated with P. acnes. The antimicrobial activity of recombinant full-length DCD (50 μg/ml) was 97% against Escherichia coli and 100% against Staphylococcus aureus. Antimicrobial activity against P. acnes ranged from 68% at 50 μg/ml DCD to 83% at 270 μg/ml DCD. DCD concentration in sweat from patients with acne vulgaris (median 9.8 μg/ml, range 6.9-95.3 μg/ml) was significantly lower than in healthy subjects (median 136.7 μg/ml, range 45.4-201.6 μg/ml) (p = 0.001). DCD demonstrated concentration-dependent, but partial, microbicidal activity against P. acnes. These results suggest that reduced DCD concentration in sweat in patients with inflammatory acne may permit proliferation of P. acnes in pilosebaceous units, resulting in progression of inflammatory acne.

Viable bacteria associated with red blood cells and plasma in freshly drawn blood donations

Objectives

Infection remains a leading cause of post-transfusion mortality and morbidity. Bacterial contamination is, however, detected in less than 0.1% of blood units tested. The aim of the study was to identify viable bacteria in standard blood-pack units, with particular focus on bacteria from the oral cavity, and to determine the distribution of bacteria revealed in plasma and in the red blood cell (RBC)-fraction.

Design

Cross-sectional study. Blood were separated into plasma and RBC-suspensions, which were incubated anaerobically or aerobically for 7 days on trypticase soy blood agar (TSA) or blue lactose plates. For identification colony PCR was performed using primers targeting 16S rDNA.

Setting

Blood donors attending Capital Region Blood Bank, Copenhagen University Hospital, Rigshospitalet, Hvidovre, Denmark, October 29^th to December 10^th 2013.

Participants

60 donors (≥50 years old), self-reported medically healthy.

Results

Bacterial growth was observed on plates inoculated with plasma or RBCs from 62% of the blood donations. Growth was evident in 21 (35%) of 60 RBC-fractions and in 32 (53%) of 60 plasma-fractions versus 8 of 60 negative controls (p = 0.005 and p = 2.6x10^-6, respectively). Propionibacterium acnes was found in 23% of the donations, and Staphylococcus epidermidis in 38%. The majority of bacteria identified in the present study were either facultative anaerobic (59.5%) or anaerobic (27.8%) species, which are not likely to be detected during current routine screening.

Conclusions

Viable bacteria are present in blood from donors self-reported as medically healthy, indicating that conventional test systems employed by blood banks insufficiently detect bacteria in plasma. Further investigation is needed to determine whether routine testing for anaerobic bacteria and testing of RBC-fractions for adherent bacteria should be recommended.

[The use of real time PCR for quantitative determination of some propionic bacteria residing on human skin]

A test system has been developed for determination of propionic bacterial species residing on human skin. This system developed in the real time PCR format is applicable for quantitative determination and also detection of genomes of the following Propionibacterium species: P. acnes, P. granulosum and P. avidum. This system was used for analysis of wash samples from the skin of 17 pentathlon sportsmen and 16 students. All three species of propionic bacteria were found in all skin wash samples. However, contamination with P. acnes was two times higher in control group than in the group of pentathlon sportsmen.

Deciphering the intracellular fate of Propionibacterium acnes in macrophages

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.

A mouse model of chronic prostatic inflammation using a human prostate cancer-derived isolate of Propionibacterium acnes

BACKGROUND

Prostatic inflammation has been linked to a number of prostatic diseases such as benign prostatic hyperplasia (BPH), prostatitis syndromes, and prostate cancer. Major unanswered questions include what pathogenic mechanisms, such as bacterial infections, may drive the accumulation of inflammatory infiltrates in the human prostate, and how inflammation might contribute to disease. To study this potential link in an in vivo system, we developed a mouse model of long-term bacteria-induced chronic inflammation of the prostate using a human prostatectomy-derived strain of Propionibacterium acnes.

METHODS

C57BL/6J mice were inoculated, via urethral catheterization, with vehicle control or a prostatectomy-derived strain of P. acnes (PA2). Animals were assessed at 2 days, 1, 2, or 8 weeks post-inoculation via histology and immunohistochemistry (IHC).

RESULTS

PA2 inoculation resulted in severe acute and chronic inflammation confined to the dorsal lobe of the prostate. Chronic inflammation persisted for at least 8 weeks post-inoculation. Inflammatory lesions were associated with an increase in the Ki-67 proliferative index, and diminished Nkx3.1 and androgen receptor (AR) production. Interestingly, the observed response required live bacteria and both IHC and in situ hybridization assays for P. acnes indicated a potential intracellular presence of P. acnes in prostate epithelial cells.

CONCLUSIONS

To our knowledge, this is the first mouse model of long-term prostatic inflammation induced by P. acnes, and more generally, any prostatectomy-derived bacterial isolate. This model may serve as a valuable preclinical model of chronic prostatic inflammation that can be used to mechanistically study the link between inflammation and prostatic disease.

Eradication of Propionibacterium acnes biofilms by plant extracts and putative identification of icariin, resveratrol and salidroside as active compounds

Propionibacterium acnes is a Gram-positive bacterium that plays an important role in the pathogenesis of acne vulgaris. This organism is capable of biofilm formation and the decreased antimicrobial susceptibility of biofilm-associated cells may hamper efficient treatment. In addition, the prolonged use of systemic antibiotic therapy is likely to lead to the development and spread of antimicrobial resistance. In the present study we investigated whether P. acnes biofilms could be eradicated by plant extracts or their active compounds, and whether other mechanisms besides killing of biofilm cells could be involved. Out of 119 plant extracts investigated, we identified five with potent antibiofilm activity against P. acnes (extracts from Epimedium brevicornum, Malus pumila, Polygonum cuspidatum, Rhodiola crenulata and Dolichos lablab). We subsequently identified icariin, resveratrol and salidroside as active compounds in three of these extracts. Extracts from E. brevicornum and P. cuspidatum, as well as their active compounds (icariin and resveratrol, respectively) showed marked antibiofilm activity when used in subinhibitory concentrations, indicating that killing of microbial cells is not their only mode of action.

Pharmacological properties of Myrtacine® and its potential value in acne treatment

This study aimed at evaluating the antiproliferative, antibacterial, and anti-inflammatory properties of an ethanolic myrtle extract (Myrtacine®) in vitro, characterising its potential active compounds (myrtucommulones A and B') by structural analysis, and evaluating their biological activity. Antiproliferative activity was assessed by the BrdU incorporation assay in HaCat keratinocytes and inhibitory and bactericidal activities against P. ACNES strains by measuring the minimal inhibitory concentration (MIC) and D value. Anti-inflammatory effect was evaluated by measuring 6-keto-prostaglandin F1 α and [³H]-arachidonic acid metabolite production in keratinocytes stimulated for inflammation. Myrtacine® inhibited keratinocyte proliferation by 27 % and 76 % at 1 and 3 µg/mL, respectively (p < 0.001). A comparable effect, though less marked, was observed with 5 µg/mL myrtucommulones A and B' (-36 % and -28 %, respectively). Myrtacine® inhibited erythromycin-sensible and -resistant P. ACNES strains growth with MICs of 4.9 µg/mL and 2.4 µg/mL, respectively. Myrtucommulone B' and myrtucommulone A displayed a similar inhibitory activity against both strains (for both strains, MIC = 1.2 µg/mL and about 0.5 µg/mL, respectively). At 3 and 10 µg/mL, Myrtacine® significantly decreased all metabolite production from cyclooxygenase (81 % and 107 %, p < 0.0001) and lipoxygenase (52 % and 95 %, p < 0.001) pathways. Finally, Myrtacine® exhibited a concentration-dependent anti-lipase activity at 100 µg/mL and 1 mg/mL, as it decreased lipase activity by respectively 53 % and 100 % (p < 0.01 for both). In conclusion, in vitro, Myrtacine® demonstrated antiproliferative, antibacterial, and anti-inflammatory properties that may be of value to exert a global action in the treatment of acne lesions.

Antibacterial properties of a glycolipid-rich extract and active principle from Nunavik collections of the macroalgae Fucus evanescens C. Agardh (Fucaceae)

This study investigated the antibacterial activity of glycolipid-rich extracts of the brown macroalga Fucus evanescens in cell culture. Accessions were collected on the Arctic coast of Ungava Bay, Nunavik, Quebec. The crude ethyl acetate extract of these accessions showed strong antibacterial activity (≥4 log(10) cfu) against Hemophilus influenzae , Legionella pneumophila , Propionibacterium acnes (ATCC and clinical isolate), and Streptococcus pyogenes at 100 µg/mL. This algal extract inhibited by 3 log(10) Clostridium difficile and methicillin-resistant Staphylococcus aureus , whereas Bacillus cereus , Escherichia coli , Klebsiella pneumoniae , and Pseudomonas aeruginosa were not significantly affected. Further investigations of the activity of a glycolipid-rich fraction, extracted with dichloromethane, against Propionibacterium acnes showed an MIC(100) of 50 µg/mL, with an inhibition of more than 99% at only 7.8 µg/mL. The main active compound, a β-d-galactosyl O-linked glycolipid, was synthesized for the bioassay and showed an MIC(100) of 50 µg/mL but lost its activity more quickly with only 50% of inhibition at 12.5 µg/mL. Therefore, the semipurified F. evanescens extract could be a good choice for future research into the development of alternative treatments for acne therapy.

Cathelicidin-BF, a snake cathelicidin-derived antimicrobial peptide, could be an excellent therapeutic agent for acne vulgaris

Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O₂^.− production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O₂^.− production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris.

Production of superoxide anions by keratinocytes initiates P. acnes-induced inflammation of the skin

Acne vulgaris is a chronic inflammatory disorder of the sebaceous follicles. Propionibacterium acnes (P. acnes), a gram-positive anareobic bacterium, plays a critical role in the development of these inflammatory lesions. This study aimed at determining whether reactive oxygen species (ROS) are produced by keratinocytes upon P. acnes infection, dissecting the mechanism of this production, and investigating how this phenomenon integrates in the general inflammatory response induced by P. acnes. In our hands, ROS, and especially superoxide anions (O₂^•−), were rapidly produced by keratinocytes upon stimulation by P. acnes surface proteins. In P. acnes-stimulated keratinocytes, O₂^•− was produced by NAD(P)H oxidase through activation of the scavenger receptor CD36. O₂^•− was dismuted by superoxide dismutase to form hydrogen peroxide which was further detoxified into water by the GSH/GPx system. In addition, P. acnes-induced O₂^•− abrogated P. acnes growth and was involved in keratinocyte lysis through the combination of O₂^•− with nitric oxide to form peroxynitrites. Finally, retinoic acid derivates, the most efficient anti-acneic drugs, prevent O₂^•− production, IL-8 release and keratinocyte apoptosis, suggesting the relevance of this pathway in humans.

Acne vulgaris is a chronic inflammatory disorder of the sebaceous follicles. It is the most common skin disease, affecting up to 80% of individuals at some point between the ages of 11 and 30 years. Propionibacterium acnes (P. acnes) plays a role in the development of inflammatory acne lesions, but whether it causes inflammation by itself or through indirect mechanisms is not clear yet. Therefore, by exposing epidermal cells to P. acnes in vitro, we tested whether reactive oxygen species (ROS) production (oxidative burst) was involved in the inflammatory process. We found that one particular ROS, superoxide anion, was generated by epidermal cells following P. acnes stimulation. This phenomenon is associated with the production of a soluble pro inflammatory molecule, IL-8, and epidermal cell death. The abrogation of P. acnes-induced oxidative burst by the most commonly used and most efficient treatments of acne suggests that superoxide anions produced by epidermal cells are critical in the development of acne inflammatory lesions.

Sonication is superior to scraping for retrieval of bacteria in biofilm on titanium and steel surfaces in vitro

BACKGROUND AND PURPOSE

Low-virulence implant infections are characterized by bacterial colonization of the implant with subsequent biofilm formation. In these cases, soft tissue biopsies often prove to be culture negative. Consequently, detachment of the causative adherent bacteria is crucial for correct microbiological diagnosis. Using an in vitro model, we compared 4 methods of biofilm sampling from metal surfaces.

METHODS

Discs of titanium and steel were incubated in the presence of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Propionibacterium acnes in Mueller Hinton broth. Non-adherent bacteria were removed by repeated rinsing of the discs. 10 parallels of each disc were subjected to 1 of 4 methods for bacterial recovery: (A) sonication of the discs, (B) scraping of the discs using surgical blades followed by streaking of the blades onto agar plates, (C) scraping of the discs followed by vortex mixing of the surgical blades, and (D) scraping of the discs followed by sonication of the surgical blades. Quantitative bacterial cultures were performed for each sampling method.

RESULTS

With the exception of S. epidermidis on steel, sonication efficiently and reliably dislodged biofilm bacteria. The scraping methods employed did not detach bacteria embedded in biofilm.

INTERPRETATION

Scraping of metal surfaces is not an adequate method for sampling of biofilm bacteria in vitro.

Cryptomeria japonica essential oil inhibits the growth of drug-resistant skin pathogens and LPS-induced nitric oxide and pro-inflammatory cytokine production

In this study, the chemical composition of Cryptomeria japonica essential oil (CJE) was analyzed and its biological activities were tested. CJE was obtained by steam distillation from leaves collected from Jeju Island and analyzed by gas chromatography (GC)-flame ionization detection (FID) and GC-MS. Kaurene (17.20%), elemol (10.88%), gamma-eudesmol (9.41%), and sabinene (8.86%) were the major components in CJE. The antibacterial and anti-inflammatory activities of CJE against drug-susceptible and -resistant skin pathogens have been not reported previously. Thus, we determined the anti-bacterial activities of CJE using the disk diffusion method and minimum inhibitory concentration (MIC) values. CJE showed excellent antibacterial activities against Propionibacterium acnes and Staphylococcus epidermidis, which are acne-causing bacteria. The MIC of CJE against drug-susceptible and -resistant P. acens and S. epidermidis ranged from 0.16 to 10.0 microl/ml. In addition, the effects of CJE on nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages were also examined. Pro-inflammatory cytokine and mediator tests indicated that CJE has excellent dose-dependent inhibitory activities. Therefore, based on these results, we propose that CJE is an attractive acne-mitigating candidate for skin health.

Solid Lipid Microparticles (SLM) Containing Juniper Oil as Anti-Acne Topical Carriers: Preliminary Studies

Solid lipid microparticles (SLM) were used as carriers of juniper oil and proposed for the topical treatment of acne vulgare. The formulations were obtained by the o/w emulsification method. Compritol and Precirol were employed as lipidic materials. Emulsions containing 1.5% (w/w) of lipophilic phase (lipid and oil) and two different lipid to oil ratios (1:1 and 2:1) were prepared. Blank particles were also prepared, as a comparison. The SLM were characterized in terms of encapsulation efficiency, size, and morphology. The particle size stability in aqueous dispersions was monitored over one month. Evaporation of volatile compounds of oil from microparticles by weight loss was investigated. The qualitative composition of Juniper oil before and after the encapsulation process was determined by gas chromatography (GC) and gas chromatography/mass spectrum (GC/MS) analyses. The antimicrobial activity of the oil encapsulated into the lipid microparticles against P. acnes was studied as contact time assay and compared to the activity of the oil not encapsulated. The emulsification method here described was a good technique for the encapsulation of essential oils. Percentage yields of production and encapsulation efficiencies were higher for Compritol preparations than for these prepared using Precirol. All preparations were characterized by similar particle size distributions (dvs about 3-4 microm) regardless of lipid type and lipid to oil ratios. Microscopy observations showed that the microparticles in aqueous dispersions had almost spherical shape, independently from their composition. The scanning electron microscopy (SEM) analyses showed that when the particles were dried, they had an irregular shape and a rough surface. The SLM dispersions based on Compritol revealed particle size stability over the investigated period of 30 days. In contrast, an increase of the mean dimensions in the preparations containing Precirol was observed. A low loss of volatile oil compounds owing to evaporation from dry particles was found in all preparations. This indicated that the microparticles were able to substantially maintain the oil loaded inside their lipidic structure, reducing its volatility. Some modifications of composition were found in the oil encapsulated in SLM with respect to the juniper oil raw material, but these modifications did not decrease the antibacterial activity of the oil. The SLM here described are promising carriers for the development of anti-acne topical formulations containing Juniper oil.

[Acne. Current pathophysiologic considerations]

Seborrhea, follicular hyperkeratosis, propionibacteria, and inflammatory reactions are the most important factors leading to acne. The combination of increased sebum producation and follicular hyperkeratosis facilitates an increased growth of Propionibacterium acnes. Its metabolic products lead to follicular inflammation and, in extreme cases, even to perifollicular abscesses. Sebum production is influenced by androgens, so that abnormalities in androgen levels can produce seborrhea and acne. Follicular hyperkeratosis may be triggered by a relative deficiency in linoleic acid, peroxides from sebum components, and especially by inflammatory mediators such as interleukin-1. Bacterial metabolic products such as lipases, proteases, or chemotactic factors lead to the perifollicular inflammation. This inflammation is not only a response to other pathogenetic factors, but also a cause of acne. An initial mild perifollicular inflammation can induce comedogenesis via a variety of mediators. The influence of dietary factors on the initiation and course of acne has recently received increased recognition. A connection has been postulated between acne and a high nutrients with glycemic index, as well as with milk products.

Propionibacterium acnes lacks the capability to proliferate in platelet concentrates

BACKGROUND AND OBJECTIVES

Propionibacterium acnes is considered to be one of the most frequent contaminants of platelet concentrates (PCs) when anaerobic culture-based detection methods are used. But Propionibacteria are often detected too late when blood products have already been transfused. Therefore, its transfusion relevance is still demanding clarification because studies of the outcome of patients transfused with P. acnes-contaminated PCs are still uncommon. In this study, we monitored clinical effects in patients after transfusion of PCs, which were detected too late in sterility testing. Furthermore, we assessed the bacterial proliferation of Propionibacterium species seeded into PCs to clarify their significance for platelet bacteria screening.

MATERIALS AND METHODS

In the look-back process, we followed the route of the putative contaminated PC units from storage to transfusion. In the in vitro study, PCs were inoculated with 1-100 colony-forming unit (CFU)/ml of clinical isolates of Propionibacteria (n = 10). Sampling was performed during 10-day aerobic storage at 22 degrees C. The presence of bacteria was assessed by plating culture and automated BacT/Alert culture system.

RESULTS

Propionibacterium acnes shows slow or no growth under PC storage conditions. Clinical signs of adverse events after transfusion of potentially contaminated PC units were not reported.

CONCLUSION

Propionibacteria do not proliferate under PC storage conditions and therefore may be missed or detected too late when blood products have already been transfused.

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.

In vitro activity of kaempferol isolated from the Impatiens balsamina alone and in combination with erythromycin or clindamycin against Propionibacterium acnes

The in vitro antibacterial activity against antibiotic-resistant Propionibacterium acnes of kaempferol isolated from the Impatiens balsamina alone and in combination with erythromycin or clindamycin antibiotics was investigated. The antibiotic combination effect against antibiotic-resistant P. acnes was studied by checkerboard test. Kaempferol and quercetin demonstrated antibacterial activities against P. acnes. Minimum inhibitory concentrations (MICs) for both compounds were < or =32 ug/ml and < or =64 ug/ml for clindamycin-sensitive and-resistant P. acnes, respectively. The four combination formulations (kaempferol and either erythromycin or clindamycin; quercetin and either erythromycin or clindamycin) exhibited a synergic inhibition of P. acnes growth. The combination of kaempferol with quercetin showed an indifferent effect. The combination of clindamycin with kaempferol or quercetin showed a greater synergic effect than that of erythromycin with kaempferol or quercetin. Thus, these combinations demonstrated the potential to treat acne.

Biofilm formation of the pathogens of fatal bacterial granuloma after trauma: potential mechanism underlying the failure of traditional antibiotic treatments

The pathogen of a new type of disease - fatal bacterial granuloma after trauma (FBGT) - was found to be Propionibacterium acnes (P. acnes). Although in vitro studies showed that the pathogenic P. acnes are sensitive to conventional antibiotics, treatments of FBGT patients with these antibiotics were ineffective. The underlying mechanisms were not clear. Since P. acnes are able to form biofilm on orthopaedic biomaterials in vitro, and pathogenic P. acnes of acnes vulgaris was known to form biofilm in vivo, we hypothesize that the pathogens of FBGT are also able to form biofilm during the pathogenesis, which may be 1 of the reasons for antibiotics tolerance of FBGT. Biofilm forming capacity of the pathogens of FBGT were examined with XTT reduction method, as well as with scanning electron microscope. The effect of long-term subminimal inhibitory concentration (MIC) lincomycin on the biofilm forming ability of the pathogens was also tested. Our results show that both the type strain (NCTC737) and the pathogenic P. acnes of FBGT can form biofilm in vitro. These data demonstrated the biofilm formation of the FBGT pathogens in vitro, and its acceleration by lincomycin, which may be 1 of the major mechanisms for the failure of antibiotic treatment.

Effect of adjunctive treatment with intravenously administeredPropionibacterium acneson reproductive performance in mares with persistent endometritis

OBJECTIVE

To determine whether treatment with a preparation of Propionibacterium acnes would improve pregnancy and live foal rates in mares with persistent endometritis.

DESIGN

Randomized placebo-controlled clinical trial.

ANIMALS

95 mares with a cytologic diagnosis of persistent endometritis.

PROCEDURES

Mares were treated with P acnes or placebo (both administered IV) on days 0, 2, and 6. No attempt was made to alter additional treatments administered by attending veterinarians. Information on breeding history, physical examination findings, results of cytologic examination and microbial culture of uterine samples, additional treatments administered, breeding dates, results of pregnancy examinations, whether a live foal was produced, and reactions to treatment was recorded.

RESULTS

In multivariate logistic regression models, mare age, year of entry into the study, and first breeding within 8 days after first treatment with P acnes or placebo were significantly associated with pregnancy. Fewer number of cycles bred and younger age were significantly associated with delivery of a live foal in a separate multivariate analysis. Results of multivariate logistic regression modeling indicated that mares treated with P acnes were more likely to become pregnant and to deliver a live foal, compared with placebo-treated controls.

CONCLUSIONS AND CLINICAL RELEVANCE

IV administration of P acnes as an adjunct to conventional treatments in mares with a cytologic diagnosis of persistent endometritis improved pregnancy and live foal rates. The optimal effect was detected in mares bred during the interval extending from 2 days before to 8 days after first treatment with P acnes.

The Propionibacterium acnes genome: from the laboratory to the clinic

The genome of Propionibacterium acnes, the microbe presumed to be at least partially etiologic for the development of acne, has recently been decoded. The genome supports long-standing concepts regarding acne pathogenesis, but also demonstrates heretofore unknown and/or unsuspected bacterial properties, which might play a role in disease occurrence. In turn, understanding the genome may lead to new therapeutic avenues, as summarized in this manuscript.

Resveratrol inhibition of Propionibacterium acnes

OBJECTIVES

To evaluate the effects of the anti-inflammatory hydroxystilbene, resveratrol, on Propionibacterium acnes growth.

METHODS

Three different strains of P. acnes were tested against resveratrol at concentrations between 0 and 200 mg/L. Piceatannol was included as a second hydroxystilbene to compare with resveratrol, and erythromycin and benzoyl peroxide were used as positive controls.

RESULTS

After 24 h of treatment with resveratrol, the average 50% inhibitory concentration (IC(50)) was 73 mg/L and the average 100% inhibitory concentration (IC(100)) was 187 mg/L for the three strains of P. acnes tested. The IC(50) and IC(100) of piceatannol were 123 and 234 mg/L, respectively. The highest concentration of resveratrol tested (200 mg/L) was bactericidal, whereas lower concentrations were bacteriostatic.

CONCLUSIONS

Resveratrol, an anti-inflammatory hydroxystilbene, is capable of inhibiting P. acnes growth.

Biofilm formation by Propionibacterium acnes is associated with increased resistance to antimicrobial agents and increased production of putative virulence factors

Propionibacterium acnes plays an important role in the pathogenesis of acne vulgaris, a common disorder of the pilosebaceous follicles. Recently, it was suggested that P. acnes cells residing within the follicles grow as a biofilm. In the present study, we tested the biofilm-forming ability of several P. acnes strains in a microtiter plate model. We also evaluated the resistance of biofilm-grown P. acnes towards antimicrobial agents commonly used in the treatment of acne and the production of putative virulence factors. Our results indicate that P. acnes can form biofilms in vitro. The results also show that sessile P. acnes cells are more resistant to various commonly used antimicrobial agents than planktonic cells. In addition, sessile cells produce more extracellular lipases as well as significant amounts of the quorum-sensing molecule autoinducer-2.

Infections associated with orthopedic implants

PURPOSE OF REVIEW

We review recent advances in the prevention, diagnosis and treatment of infections associated with joint prostheses and internal fixation devices.

RECENT FINDINGS

The perioperative antimicrobial prophylaxis should be administered 60-30 min before incision or before inflation of the tourniquet. New diagnostic approaches include sonication of removed implants to dislodge adherent microorganisms growing in biofilms and the use of molecular techniques to improve diagnostic yield. Treatment of implant-associated infections without removal of the device is an established option for selected patients. Treatment with rifampin combinations in staphylococcal infections is crucial for success. As demonstrated in vitro, in animal studies and in clinical trials, quinolones are suitable combination agents with rifampin against susceptible staphylococci, but increasing antimicrobial resistance requires evaluation of alternative combination agents, such as quinpristin-dalfopristin, linezolid, and daptomycin, although clinical experience is limited. New antimicrobial agents, such as dalbavancin, tigecycline, iclaprim, and novel rifamycin derivatives are studied.

SUMMARY

Better understanding of the interaction between microorganisms, the implant and the host may improve our current approach to the diagnosis and treatment of implant-associated infections. The treatment modality depends on duration of infection, stability of the implant, antimicrobial susceptibility of the pathogen and condition of the surrounding soft tissue.

In vivo and in vitro effect of killed Propionibacterium acnes and its purified soluble polysaccharide on mouse bone marrow stem cells and dendritic cell differentiation

Among the effects exerted by Propionibacterium acnes, a most relevant one is its capacity to modulate the Th1/Th2 cellular immune response. This effect depends on the induction and activation of antigen presenting cells, mainly dendritic cells (DCs), whose number is increased in the peripheral blood of animals treated with this bacterium. A soluble P. acnes polysaccharide (PS) extract also acts on DCs, modulating a Th1 immune response. These data led us to investigate the role of P. acnes and its soluble PS on murine bone marrow (BM) DCs. Bone marrow cells were analyzed by flow cytometry, showing an increase of stem cells and DCs in P. acnes- or PS-treated animals. Culturing in the presence of granulocyte monocyte colony stimulating factor (GM-CSF) increased the in vitro differentiation and maturation of these cells into BM-derived DCs (CD11c+ and MHC class II+). Maturation of DCs was determined by increased CD80 and CD86 expression, IL-4 and IL-12 production, reduction in phagocytic capacity and increase in the antigen presenting ability to primed or naïve T lymphocytes. These data indicate that P. acnes as well as its PS can modulate BM stem cells, originating mature DCs, which are important mainly at the initial antigen contact.

Propionibacterium acnes wound contamination at the time of spinal surgery

Bacteria of the normal skin microbiota such as Propionibacterium acnes and coagulase-negative staphylococci often are dismissed as contaminants when detected in clinical samples. Propionibacterium acnes is described as a cause of spinal infection and more recently has been linked to sciatica. To date no researchers formally have examined the incidence of bacterial wound contamination during spinal surgery. Surgical specimens were removed from 79 patients having spinal surgery for analysis using agar culture detection, broth enrichment, and immunofluorescence microscopy. Bacteria were identified in 29.1% of skin samples, 21.5% of tissue samples and 16.5% of washings retrieved from operative wounds. Propionibacterium acnes was identified more frequently than Staphylococcus spp in each of the three sample types. Bacteria were detected using enrichment in 9 (11%) patients and using fluorescence microscopy in 15 (19%). The results of immunofluorescence microscopy suggest that Propionibacterium acnes detected in wounds originates from patient skin. Bacteria from contaminated wounds appeared as single cells using fluorescence microscopy; however previous work shows that bacteria from infected hip prosthesis are observed as large aggregates. Therefore, it is suggested that immunofluorescence microscopy is a useful tool to help discriminate between surgical contamination and infection.

LEVEL OF EVIDENCE

Diagnostic study, Level I (prospective study). See the Guidelines for Authors for a complete description of levels of evidence.

CAMP factor homologues in Propionibacterium acnes: a new protein family differentially expressed by types I and II

Analysis of the draft genome sequence of the opportunistic pathogenPropionibacterium acnestype strain NCTC 737 (=ATCC 6919) revealed five genes with sequence identity to the co-haemolytic Christie–Atkins–Munch-Peterson (CAMP) factor ofStreptococcus agalactiae. The predicted molecular masses for the expressed proteins ranged from 28 to 30 kDa. The genes were present in each of the three recently identifiedrecA-based phylogenetic groupings ofP. acnes(IA, IB and II), as assessed by PCR amplification. Conserved differences in CAMP factor gene sequences between these three groups were also consistent with their previous phylogenetic designations. All type IA, IB and II isolates were positive for the co-haemolytic reaction on sheep blood agar. Immunoblotting and silver staining of SDS-PAGE gels, however, revealed differential protein expression of CAMP factors amongst the different groups. Type IB and II isolates produced an abundance of CAMP factor 1, detectable by specific antibody labelling and silver staining of SDS-PAGE gels. In contrast, abundant CAMP factor production was lacking in type IA isolates, although larger amounts of CAMP factor 2 were detectable by immunoblotting compared with type II isolates. While the potential role of the abundant CAMP factor 1 in host colonization or virulence remains to be determined, it should be noted that the type strain ofP. acnesused in much of the published literature is a type IA isolate and is, therefore, lacking in this attribute.

Evaluation of the antibacterial efficacy of diesters of azelaic acid

A number of diesters of the topical dermatosis treatment azelaic (nonanedioic) acid were prepared and tested for antibacterial effect. Two esters, bis-[(hexanoyloxy)methyl] nonanedioate and especially bis-[(butanoyloxy)methyl] nonanedioate showed promising activity against acne related bacteria in vitro. No activity of azelaic acid was detected in Mueller Hinton II agar at pH 7.3 when using the agar diffusion method, whereas both esters gave zones of growth inhibition. At pH 5.6, activity of azelaic acid was detected. At this pH, the zones of inhibition and MIC values obtained with azelaic acid were smaller than those of bis-[(butanoyloxy)methyl] nonanedioate for all test organisms. A preparation for topical use containing 20% (w/w) bis-[(butanoyloxy)methyl] nonanedioate, and the commercially available Skinoren (20% (w/w) azelaic acid), were compared for antibacterial effect against cutaneous bacteria using contact plate analyses of the skin. Though Skinoren was usually most effective, the differences were not statistically significant. Furthermore, bacteria surviving contact with the topical preparations were invariably more sensitive to the ester than to azelaic acid upon subculturing onto agar (pH 5.6) containing either preparation at 0.2-0.7 mg/ml. This might indicate that other factors, such as the composition of the cream base, mitigate the antibacterial activity of the ester. It is proposed that the pharmacological and microbiological properties of bis-[(butanoyloxy)methyl] nonanedioate are worthy of further study based on an extended screening of acne sufferers.

[The study of the pro-nucleating activity of bacteria identified in cholesterol gallstones in model bile systems]

OBJECTIVE

To explore the relationship of bacteria identified in cholesterol gallstones and gallstone formation.

METHODS

Observe the bacteria activity in model bile and the influence of bacteria on the cholesterol nucleation time (NT).

RESULTS

(1) Model bile were suitable for the growth of E. coli, Pseudomonas aeruginosa, staphylococcus aureus, enterococcus faecalis, clostridium difficile and Clostridium. Propionibacterium acne grew weakly and the growth of Bacteroides fragilis was restrained in model bile. (2) Only pseudomonas aeruginosa and enTerococcus faecalis could ly shorten the cholesterol nucleation time. (3) With pseudomonas aeruginosa or enTerococcus faecalis added in model bile, the formation of cholesterol crystals presented a progressive course of evolution.

CONCLUSIONS

Pseudomonas aeruginosa and enterococcus faecalis, not propionibacterium acne, have pro-nucleating ability in model bile.

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

Eukaryotic tissue culture appears to be a suitable model for measuring the bacterial cytotoxic effect. Propionibacterium acnes strains were isolated from corneal tissue removed by keratoplastic surgery from patients with corneal dystrophy or bullous keratopathy. The cytotoxic effect of the filtrates of 10 P. acnes strains were studied by means of measuring the decrease of the mitochondrial dehydrogenase activities of viable epithelial (HeLa) and fibroblastic (BHK-21) cell cultures. A time and concentration dependent, reversible cytotoxic effect was detected in both tissue types. The results also showed that strains of P. acnes are capable of surviving anaerobic conditions for as long as 8 months and suggest that production cytotoxic effects during the long persistence it may harm human tissue.

Molecular diagnosis of a vascular prosthesis infection, due to Propionibacterium acnes, by amplification and sequencing of 16S rDNA

We describe a case of indolent vascular prosthesis infection due to Propionibacterium acnes. The microorganism was identified only by amplification and sequencing of 16S rDNA, while standard cultures remained negative. This observation underscores the usefulness of molecular techniques for the diagnosis of infection caused by fastidious microorganisms.

Effekt einer neuen Oberfl�chenbehandlung von Intraokularlinsen aus Silikon durch ein Fluoralkylsilan auf das Adh�renzverhalten Endophthalmitis-relevanter Bakterien in vitro

INTRODUCTION

Dynasilan is a fluoroalkylsilan which is able to bind to surface active molecules of intraocular lenses (IOLs), thereby offering a new option for surface modification of silicone lenses. The purpose of this in vitro study was to investigate the influence of this new surface treatment on the adherence of two typical endophthalmitis-inducing bacteria ( Staphylococcus epidermidis, Propionibacterium acnes).

MATERIALS AND METHODS

A total of 14 Dynasilan-treated and 14 untreated silicone lenses were incubated at 37 degrees C for 24 h in brain heart infusion broth (10(8) CFU/ml) either with Staphylococcus epidermidis or with Propionibacterium acnes for 1 h. Subsequently, the adherent bacteria were resuspended using ultrasonification at 35 kHz for 3 x 45 s. After a dilution series and incubation at 37 degrees C for 24 h or 3 days the colonies were counted.

RESULTS

On untreated IOLs incubated with Staphylococcus epidermidis the average number of bacteria was 3.6 x 10(7)/ml, and on treated IOLs the number of counted colonies was reduced to 1.09 x 10(7)/ml. Incubated with Propionibacterium acnes the average number of adherent bacteria on untreated IOLs was 4.75 x 10(4)/ml and on modified IOLs the number was reduced to 2.94 x 10(4)/ml.

CONCLUSION

Dynasilan surface treatment may reduce the adherence of Staphylococcus epidermidis and Propionibacterium acnes on silicone intraocular lenses. Further studies regarding the stability of this treatment, its biocompatibility and influence on lens epithelial cell adhesion are in progress.

Proton magic angle spinning NMR reveals new features in photodynamically treated bacteria

The bacterium Propionibacterium acnes is light-sensitive due to porphyrin-induced photosensitization. The light sensitivity increases with incubation of 5-aminolevulinic acid, ALA. For the first time, 1H magic angle spinning NMR spectroscopy is used to describe the photoinduced changes in the bacterium after ALA incubation. Successful photosensitization was performed with light-emitting diodes in the blue and red regions (430 and 654 nm, respectively). The irradiation setup, suitable for irradiation of bacterium suspensions in petri dishes is described. For NMR studies blue light diodes with about 90 micromol/m2s were chosen. After blue light irradiation, the endogenous glycine betaine, proline, glutamate and choline levels in P. acnes decreased with increasing irradiation time. For sublethal light doses (50% survival fraction), the endogenous glycine betaine level decreased 80% on average. The corresponding percentages for proline, choline and glutamate were about 40, 25 and 10, respectively. It is hypothesized that the irradiation, inducing porphyrin photosensitization amplified by ALA incubation, leads to elimination of the osmolyte glycine betaine and possibly also proline by so-called regulatory volume decrease (RVD) mechanisms. These mechanisms are known to be active in several prokaryotic and eukaryotic cells when exposed to hypotonic stress. They are also known to be present in several eukaryotic cells during photodynamic therapy (PDT) exposure leading to hypotonoc stress. The findings contribute to the knowledge of the inactivation mechanisms of P. acnes in photosensitization, and could therefore be of interest in the efforts to use PDT as treatment of the acne disease.

Comparative efficacy of clindamycin and benzoyl peroxide for in vivo suppression of Propionibacterium acnes

BACKGROUND

Benzoyl peroxide and clindamycin are the two most widely prescribed topical antimicrobials in the treatment of acne.

AIM

To compare the antimicrobial efficacy, in vivo, of benzoyl peroxide and clindamycin against Propionibacterium acnes.

METHODS

Two groups of 10 subjects each, with comparable mean P. acnes baseline counts of log 5.75 to 5.85, underwent twice daily application of benzoyl peroxide or clindamycin for 14 days.

RESULTS

The results of quantitatively sampling P. acnes after 3, 7 and 14 days of treatment showed that Triaz 6% benzoyl peroxide special gel produced faster and significantly greater reductions in P. acnes than did the 1% clindamycin phosphate in Cleocin-T lotion (p < 0.01). These results were paralleled by the greater reductions produced by Triaz versus Cleocin (p < 0.05) in P. acnes fluorescence.

CONCLUSION

Benzoyl peroxide formulations suppress the follicular population of P. acnes more rapidly and to a greater degree than topical antibiotics such as clindamycin.

Evaluation of a new generation of culture bottle using an automated bacterial culture system for detecting nine common contaminating organisms found in platelet components

BACKGROUND

An automated bacterial culture system (BacT/ALERT 3D, bioMérieux) has been previously validated with a variety of bacteria in platelets. The recovery of bacteria in platelets using a new generation of culture bottles that do not require venting and that use a liquid emulsion sensor was studied.

STUDY DESIGN AND METHODS

Bacillus cereus, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Streptococcus viridans, and Propionibacterium acnes isolates were inoculated into Day 2 platelets to concentrations of 10 and 100 CFU per mL. Samples were then studied with current and new aerobic, anaerobic, and pediatric bottles.

RESULTS

All organisms, except P. acnes, were detected in a mean time of 9.2 to 20.4 (10 CFU/mL) or 8.7 to 18.6 (100 CFU/mL) hours. P. acnes was detected in a mean time of 69.2 (10 CFU/mL) or 66.0 (100 CFU/mL) hours. The 10-fold increase in inoculum was associated with a mean 9.2 percent difference in detection time. The aerobic, anaerobic, and pediatric bottles had a mean difference in detection time (hours) between the current and new bottles of 0.10 (p=0.61), 0.4 (p=0.38), and 1.0 (p < 0.001), respectively.

CONCLUSION

No difference in detection time between the current and new aerobic and anaerobic bottles was demonstrated. The new pediatric bottles had a small but significant delay in detection.

Lymecycline and minocycline in inflammatory acne: a randomized, double-blind intent-to-treat study on clinical and in vivo antibacterial efficacy

BACKGROUND

Some antibiotics represent a mainstay in acne treatment. However, studies comparing their efficacies are rare.

AIM

To evaluate the clinical and in vivo antibacterial effect of lymecycline and minocycline at different dosages.

METHOD

Eighty-six patients with moderate to severe acne were enrolled in a randomized, double-blind, intent-to-treat study comparing in three parallel groups the effect of (1) lymecycline 300 mg daily for 12 weeks, (2) minocycline 50 mg daily for 12 weeks and (3) minocycline 100 mg daily for 4 weeks followed by 50 mg daily for 8 weeks. Evaluations were made at the screening visit and at five on-treatment visits. They consisted of clinical counts of acne lesions and evaluations of bacterial viability using dual flow cytometry performed on microorganisms collected from sebaceous infundibula by cyanoacrylate strippings.

RESULTS

Patients receiving minocycline 100/50 mg had the best clinical outcome, particularly in the reduction of the number of papules. By the end of the trial, the microbial response to minocycline 100/ 50 mg was also superior to either of the other two treatments. There were less live and more dead bacteria.

CONCLUSION

In this trial, minocycline 100/50 mg was superior for the treatment of inflammatory acne when compared to lymecycline 300 mg and minocycline 50 mg.

Effects of instrumentation, irrigation and dressing with calcium hydroxide on infection in pulpless teeth with periapical bone lesions

AIM

The aim of this study was to evaluate the fate of microorganisms in root canals of teeth with infected pulps and periapical bone lesions with and without the use of calcium hydroxide medication.

METHODOLOGY

Endodontic samples were cultured and microorganisms were counted and identified in 43 teeth before (sample 1) and after (sample 2) treatment during the first visit and before (sample 3) and after (sample 4) treatment during the second visit. In the first visit teeth were instrumented and half of the teeth were filled with a thick slurry of calcium hydroxide in sterile saline. The other teeth were obturated with gutta-percha and AH-2 6 sealer. After 4 weeks the teeth with calcium-hydroxide were accessed again and after microbiological sampling they were obturated with gutta-percha and AH-26 sealer.

RESULTS

The mean total colony forming unit (CFU) counts of positive samples dropped significantly as a result of canal preparation during the first visit from 1.0 x 10(6) to 1.8 x 10(3) (between samples 1 and 2) but increased to 9.3 x 10(3) in the period between the two visits (sample 2 and 3). There was no difference in mean total CFU counts of positive samples between the end of the first (sample 2) and the end of the second visit (sample 4). The most frequently isolated species were Prevotella intermedia, Capnocytophaga spp.. Actinomyces odontolyticus. Propionibacterium acnes and Peptostreptococcus micros.

CONCLUSIONS

Although a calcium hydroxide paste was placed in the prepared canals, the number of positive canals had increased in the period between visits. However, the number of microorganisms had only increased to 0.93% of the original number of CFU (sample 1). It is concluded that a calcium hydroxide and sterile saline slurry limits but does not totally prevent regrowth of endodontic bacteria.