The microflora of the face and acne lesions

In vitro acne disease model from inertial focusing effect for studying the interactions between sebocyte glands and macrophages

Acne is one of the most widespread skin diseases. The acne mechanism is intricate, involving interactions between different types of cells (i.e., sebocytes and macrophages). One of the challenges in studying the mechanism of acne is that current in vitro culture methods cannot reflect the 3D cellular environment in the tissue, including inflammatory stimuli and cellular interactions especially the interactions between sebocytes and immune cells. To solve this issue, we generated an in vitro acne disease model consisting of 3D artificial sebocyte glands and macrophages through the inertial focusing effect method. Using this model, we produced a controllable inflammatory environment similar to the acne pathogenetic process in the skin. The 3D artificial sebocyte glands and macrophages can be separated for analyzing each cell type, assisting the in-depth understanding of the acne mechanism. This study indicates that proinflammatory macrophages promote lipid accumulation and induce oxidative stress in sebocyte glands. Additionally, in an inflammatory environment, sebocyte glands induce macrophage polarization into the M1 phenotype. Employing this model for drug screening, we also demonstrated that, cannabidiol (CBD), a clinically investigated drug, is effective in restoring lipid accumulation, oxidative stress, inflammatory cytokines and macrophage polarization in the acne disease.

Adipose-derived stem cells attenuate acne-related inflammation via suppression of NLRP3 inflammasome

Background

Acne is a chronic facial disease caused by Propionibacterium acnes, which proliferates within sebum-blocked skin follicles and increases inflammatory cytokine production. Several therapeutic drugs and products have been proposed to treat acne, yet no single treatment that ensures long-term treatment efficacy for all patients is available. Here, we explored the use of facial autologous fat transplant of adipose-derived stem cells (ADSCs) to dramatically reduce acne lesions.

Methods

THP-1 cells were treated with active P. acnes for 24 h at different multiplicities of infection, and alterations in inflammatory factors were detected. To study the effect of THP-1 on inflammasome-related proteins, we first co-cultured ADSCs with THP-1 cells treated with P. acnes and evaluated the levels of these proteins in the supernatant. Further, an acne mouse model injected with ADSCs was used to assess inflammatory changes.

Results

Propionibacterium acnes-mediated stimulation of THP-1 cells had a direct correlation with the expression of active caspase-1 and interleukin (IL)-1β in an infection-dependent manner. ADSCs significantly reduced the production of IL-1β induced by P. acnes stimulation through the reactive oxygen species (ROS)/Nod-like receptor family pyrin domain-containing 3 (NLRP3)/caspase-1 pathway. The results showed that ADSCs inhibit the skin inflammation induced by P. acnes by blocking the NLRP3 inflammasome via reducing the secretion of IL-1β in vivo.

Conclusions

Our findings suggest that ADSCs can alter IL-1β secretion by restricting the production of mitochondria ROS, thereby inhibiting the NLRP3/caspase-1 pathway in P. acnes-induced inflammatory responses. This study indicates that anti‐acne therapy can potentially be developed by targeting the NLRP3 inflammasome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03007-7.

T Cell Extracellular Traps: Tipping the Balance Between Skin Health and Disease

The role of extracellular traps (ETs) in the innate immune response against pathogens is well established. ETs were first identified in neutrophils and have since been identified in several other immune cells. Although the mechanistic details are not yet fully understood, recent reports have described antigen-specific T cells producing T cell extracellular traps (TETs). Depending on their location within the cutaneous environment, TETs may be beneficial to the host by their ability to limit the spread of pathogens and provide protection against damage to body tissues, and promote early wound healing and degradation of inflammatory mediators, leading to the resolution of inflammatory responses within the skin. However, ETs have also been associated with worse disease outcomes. Here, we consider host-microbe ET interactions by highlighting how cutaneous T cell-derived ETs aid in orchestrating host immune responses against Cutibacterium acnes (C. acnes), a commensal skin bacterium that contributes to skin health, but is also associated with acne vulgaris and surgical infections following joint-replacement procedures. Insights on the role of the skin microbes in regulating T cell ET formation have broad implications not only in novel probiotic design for acne treatment, but also in the treatment for other chronic inflammatory skin disorders and autoimmune diseases.

Inhibitory Effect of Quercetin on Propionibacterium acnes-induced Skin Inflammation

Quercetin is a well-known antioxidant and a plant polyphenolic of flavonoid group found in many fruits, leaves, and vegetables. Propionibacterium acnes is a key skin pathogen involved in the progression of acne inflammation. Although quercetin has been applied to treat various inflammatory diseases, the effects of quercetin on P. acnes-induced skin inflammation have not been explored. This study investigated the effects of quercetin on P. acnes-induced inflammatory skin disease in vitro and in vivo. The results showed that quercetin suppressed the production of pro-inflammatory cytokines in P. acnes-stimulated HaCaT, THP-1 and RAW 264.7 cells. Additionally, quercetin reduced the production of TLR-2 and the phosphorylation of p38, ERK and JNK MAPKs in P. acnes-stimulated HaCaT and THP-1 cells. It also suppressed MMP-9 mRNA levels in two cell lines exposed to P. acnes in vitro. In the case of in vivo, P. acnes was intradermally injected into the ears of mice and it resulted in cutaneous erythema, swelling, and a granulomatous response. Treatment with quercetin markedly reduced ear thickness and swelling. These results suggested that quercetin can be a potential therapeutic agent against P. acnes-induced skin inflammation and may have diverse pharmaceutical and cosmetics applications.

Phages and their potential to modulate the microbiome and immunity

Bacteriophages (hence termed phages) are viruses that target bacteria and have long been considered as potential future treatments against antibiotic-resistant bacterial infection. However, the molecular nature of phage interactions with bacteria and the human host has remained elusive for decades, limiting their therapeutic application. While many phages and their functional repertoires remain unknown, the advent of next-generation sequencing has increasingly enabled researchers to decode new lytic and lysogenic mechanisms by which they attack and destroy bacteria. Furthermore, the last decade has witnessed a renewed interest in the utilization of phages as therapeutic vectors and as a means of targeting pathogenic or commensal bacteria or inducing immunomodulation. Importantly, the narrow host range, immense antibacterial repertoire, and ease of manipulating phages may potentially allow for their use as targeted modulators of pathogenic, commensal and pathobiont members of the microbiome, thereby impacting mammalian physiology and immunity along mucosal surfaces in health and in microbiome-associated diseases. In this review, we aim to highlight recent advances in phage biology and how a mechanistic understanding of phage-bacteria-host interactions may facilitate the development of novel phage-based therapeutics. We provide an overview of the challenges of the therapeutic use of phages and how these could be addressed for future use of phages as specific modulators of the human microbiome in a variety of infectious and noncommunicable human diseases.

The Skin and Gut Microbiome and Its Role in Common Dermatologic Conditions

Microorganisms inhabit various areas of the body, including the gut and skin, and are important in maintaining homeostasis. Changes to the normal microflora due to genetic or environmental factors can contribute to the development of various disease states. In this review, we will discuss the relationship between the gut and skin microbiome and various dermatological diseases including acne, psoriasis, rosacea, and atopic dermatitis. In addition, we will discuss the impact of treatment on the microbiome and the role of probiotics.

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.

Efficacy of Bacteriophages in Propionibacterium acnes-Induced Inflammation in Mice

Background

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

Objective

We investigated the effect of bacteriophages using an acne mouse model with Propionibacterium acnes-induced inflammatory nodules by clinical examination, pathology, and immunohistochemical analysis.

Methods

A human-isolated P. acnes suspension (10⁹ colony forming units/µl) was injected into the backs of HR-1 mice. Group A was used as a control, Group B was injected on the back with P. acnes 4 weeks following the initial P. acnes suspension injection, and group C was injected on the back with P. acnes and bacteriophages 4 weeks following the initial P. acnes suspension injection. Clinical and histopathological evaluations were performed.

Results

Inflammatory nodule size decreased with time in all groups. Group C showed the greatest decrease in size, followed by group B and group A. The histopathological findings showed a decrease in epidermal thickness and the number and size of microcomedone-like cysts in groups B and C compared to group A. Immunohistochemistry revealed similar expression of integrin α6, the epidermal proliferation marker, infiltration of CD4/CD8 T cells and neutrophils, and expression of myeloperoxidase, interleukin-1β, toll-like receptor-2, LL-37, and matrix metalloproteinase-2/3/9 in all three groups.

Conclusion

Using an acne mouse model with P. acnes-induced inflammatory nodules, we demonstrate that bacteriophages may constitute an alternative to conventional acne therapies. However, additional studies are needed for human applications.

Inhibitory effects of Schisandra chinensis extract on acne-related inflammation and UVB-induced photoageing

CONTEXT

Schisandra chinensis (Turcz.) Baill. (Schisandraceae) fruit extract (SFE) has been reported to induce non-specific tissue protection against inflammation in vivo. However, the effects of SFE on Propionibacterium acnes-stimulated acne and UVB-irradiated photoageing have yet to be investigated.

OBJECTIVE

To systematically investigate the effects of SFE against P. acnes and photoageing in vitro.

MATERIALS AND METHODS

Qualitative and quantitative analyses of SFE were performed by HPLC. SFE concentrations from 2.5 to 50 μg/mL were tested. Specifically, ELISA was used to examine the levels of pro-inflammatory cytokines in THP-1 cells as well as of collagen I and matrix metalloproteinases-1 in HDF cells. The anti-bacterial effect of SFE was determined using the microdilution broth method. Glutathione and malondialdehyde levels were examined using the colorimetric and TBA methods, respectively. The degree of ageing was determined by cytochemical staining.

RESULTS

SFE significantly inhibited P. acnes growth (MIC 0.5 mg/mL) and 50 μg/mL of SFE suppressed the production of interleukin-1β, interleukin-8 and tumour necrosis factor α, by 59.67%, 62.69% and 68.30%, respectively, in P. acnes-stimulated THP-1 cells. Additionally, 10 μg/mL of SFE suppressed photoageing in UVB-exposed fibroblasts by decreasing metalloproteinase levels by 88.4%, inducing collagen by 58.4% and activating the anti-oxidant defence system, by limiting lipid peroxidation by 51.1% and increasing glutathione production by 34.1% (2.5 μg/mL SFE).

DISCUSSION AND CONCLUSION

These results indicated that SFE could significantly ameliorate the inflammatory state in P. acnes-stimulated THP-1 and UVB-irradiated HDF cells, suggesting its potential as a novel agent for acne therapy and photoageing prevention.

The protective effects of melittin on Propionibacterium acnes-induced inflammatory responses in vitro and in vivo

Melittin is the main component in the venom of the honey bee (Apis mellifera). It has multiple effects including antibacterial, antiviral, and anti-inflammatory activities in various cell types. However, the anti-inflammatory mechanisms of melittin have not been elucidated in Propionibactierium acnes (P. acnes)-induced keratinocyte or inflammatory skin disease animal models. In this study, we examined the effects of melittin on the production of inflammatory cytokines in heat-killed P. acnes-induced HaCaT cells. Heat-killed P. acnes-treated keratinocytes increased the expression of pro-inflammatory cytokines and Toll-like receptor 2. However, melittin treatment significantly suppressed the expression of these cytokines through regulation of the NF-κB and MAPK signaling pathways. Subsequently, the living P. acnes (1 × 10(7) CFU) were intradermally injected into the ear of mice. Living P. acnes-injected ears showed cutaneous erythema, swelling, and granulomatous response at 24 hours after injection. However, melittin-treated ears showed markedly reduced swelling and granulomatous responses compared with ears injected with only living P. acnes. These results demonstrate the feasibility of applying melittin for the prevention of inflammatory skin diseases induced by P. acnes.

Bacteriophages infecting Propionibacterium acnes

Viruses specifically infecting bacteria, or bacteriophages, are the most common biological entity in the biosphere. As such, they greatly influence bacteria, both in terms of enhancing their virulence and in terms of killing them. Since the first identification of bacteriophages in the beginning of the 20th century, researchers have been fascinated by these microorganisms and their ability to eradicate bacteria. In this review, we will cover the history of the Propionibacterium acnes bacteriophage research and point out how bacteriophage research has been an important part of the research on P. acnes itself. We will further discuss recent findings from phage genome sequencing and the identification of phage sequence signatures in clustered regularly interspaced short palindromic repeats (CRISPRs). Finally, the potential to use P. acnes bacteriophages as a therapeutic strategy to combat P. acnes-associated diseases will be discussed.

In vitro antibiotic susceptibility patterns of Propionibacterium acnes isolated from acne patients: an Egyptian university hospital-based study

BACKGROUND

Antibiotics have been used for more than 40 years against Propionibacterium acnes (P. acnes), the most common agent of acne. Antibiotic resistance to this bacterium becomes a worldwide problem in recent years. No studies are available on antibiotic susceptibility patterns of P. acnes among Egyptian acne patients.

OBJECTIVE

To determine antibiotic susceptibility patterns of P. acnes isolated from acne patients attending the Dermatology outpatient clinic of an Egyptian university hospital to the most commonly prescribed antibiotics and to determine the difference in relation to age of patients, disease duration and previous antibiotic therapy for acne.

METHODS

Cutaneous samples were obtained from pustular acne lesions on the face of 115 patients, which were cultured in anaerobic media to demonstrate the presence of P. acnes. Antibiotic susceptibility tests of isolated P. acnes were then performed to clindamycin, erythromycin, azithromycin, oxytetracycline and doxycycline by disk diffusion method.

RESULTS

Propionibacterium acnes was isolated from 98 patients. Eighty-nine isolates were susceptible to azithromycin, followed by doxycycline and oxytetracycline isolated from 82 and 72 patients respectively. Resistance of P. acnes to clindamycin was detected in 65 patients, followed by erythromycin in 48 patients. Comparing the antibiotic susceptibility patterns of P. acnes isolated from patients with and without previous antibiotic therapy for acne revealed statistically non-significant differences as regards any of the antibiotics tested except for clindamycin and erythromycin. Statistically non-significant differences existed between antibiotic susceptibility patterns of P. acnes to all tested antibiotics regarding age of patients (< or ≥ 20 years) and disease duration (< or ≥ 2 years).

CONCLUSION

Propionibacterium acnes in vitro susceptibility patterns differed among Egyptian patients to the commonly prescribed antibiotics with the highest to lowest resistance to clindamycin, erythromycin, oxytetracycline, doxycycline and azithromycin.

The Antimicrobial Activities of Psidium guajava and Juglans regia Leaf Extracts to Acne-Developing Organisms

This study aims to present the in vitro inhibitory effect of Psidium guajava and Juglans regia leaf extracts on the main developer of acne lesions, Propionibacterium acnes (P. acnes), and other organisms that are isolated from acne lesions. Thirty-eight subjects (males and females) who had various types of acne were enrolled in the study. The contents of the acne lesions were cultured and the frequency of P. acnes (alone and with Staphylococci spp.) was 47%, whereas the frequencies for Staphylococcus aureus and Staphylococcus epidermidis were 13% and 24%, respectively. The antimicrobial activities of Psidium guajava and Juglans regia leaf extracts, determined by disk diffusion method (zone of inhibition), were compared to tea tree oil (TTO), doxycycline and clindamycin antibiotics. The zones of inhibition due to the Psidium guajava and Juglans regia leaf extracts ranged from 15.8–17.6 mm against P. acnes, 11.3–15.7 mm against S. aureus and 12.9–15.5 mm against S. epidermidis, respectively. These zones of inhibition were significantly higher than those of TTO and equivalent in case of Staphylococci spp., but less in case of P. acnes, to those obtained from doxycycline or clindamycin. It can be concluded that Psidium guajava and Juglans regia leaf extracts may be beneficial in treating acne especially when they are known to have anti-inflammatory activities.

Acne is not associated with yet-uncultured bacteria

Current clinical and microbiological information on acne fails to demonstrate a clear association between particular species, including Propionibacterium acnes, and disease, and the disease continues to be a considerable problem. To test if acne is associated with hitherto uncultured bacteria residing in diseased skin follicles, sequencing and phylogenetic analysis of approximately 5,700 amplified and cloned 16S rRNA genes were used to determine the microbial diversity in follicles from acne patients and healthy individuals and from the superficial skin of acne patients. Follicles from healthy skin were exclusively colonized by P. acnes, whereas the follicular microbiota of acne patients included, in addition, Staphylococcus epidermidis and minor proportions of other species. In comparison, samples from superficial skin showed a complex microbiota represented by 12 to 16 bacterial species. The findings of the study exclude the possibility that acne is associated with yet-uncultured bacteria and shows that healthy skin follicles constitute a remarkably exclusive habitat allowing colonization only by P. acnes.

In vitro antibacterial and anti-inflammatory effects of honokiol and magnolol against Propionibacterium sp

Honokiol and magnolol, two major phenolic constituents of Magnolia sp., have been known to exhibit antibacterial activities. However, until now, their antibacterial activity against Propionibacterium sp. has not been reported. To this end, the antibacterial activities of honokiol and magnolol were detected using the disk diffusion method and a two-fold serial dilution assay. Honokiol and magnolol showed strong antibacterial activities against both Propionibacterium acnes and Propionibacterium granulosum, which are acne-causing bacteria. The minimum inhibitory concentrations (MIC) of honokiol and magnolol was 3-4 microg/ml (11.3-15 microM) and 9 microg/ml (33.8 microM), respectively. In addition, the killing curve analysis showed that magnolol and honokiol killed P. acnes rapidly, with 10(5) organisms/ml eliminated within 10 min of treatment with either 45 microg (169.2 microM) of magnolol or 20 microg (75.2 microM) of honokiol per ml. The cytotoxic effect of honokiol and magnolol was determined by a colorimetric (3-(4,5-dimetyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) (MTT) assay using two animal cell lines, human normal fibroblasts and HaCaT. In this experiment, magnolol exhibited lower cytotoxic effects than honokiol at the same concentration, but they showed similar cytotoxicity when triclosan was employed as an acne-mitigating agent. In addition, they reduced secretion of interleukin-8 and tumor necrosis factor alpha (TNF-alpha) induced by P. acnes in THP-1 cells indicating the anti-inflammatory effects of them. When applied topically, neither phenolic compound induced any adverse reactions in a human skin primary irritation test. Therefore, based on these results, we suggest the possibility that magnolol and honokiol may be considered as attractive acne-mitigating candidates for topical application.

Microbiology's principle of biofilms as a major factor in the pathogenesis of acne vulgaris

Propionibacterium acnes reside within the pilosebaceous unit in a biofilm. As such, they live in a community of bacteria that encase themselves within an extracellular polysaccharide lining, which the organisms secrete after adherence to the surface. This gylcocalyx polymer acts as a protective exoskeleton and serves as a physical barrier, limiting effective antimicrobial concentrations within the biofilm microenvironment. The gylcocalyx polymer secreted by P. acnes as a biofilm may explain the immunogenicity of the organism as well as the clinical course of the disease. The P. acnes' biofilm model explains many aspects of acne pathogenesis and therapy, including why prolonged antibiotic treatment is needed, why antibiotic resistance is not a reliable assessment of treatment outcome, why accutane offers long-lasting effectiveness, and why benzoyl peroxide radicals are beneficial. This microbiologic principle of biofilms as applied to acne leads to numerous new pathways of assessment and exploration.

Propionibacterium acnes-induced IL-8 production may be mediated by NF-kappaB activation in human monocytes

Propionibacterium acnes (P. acnes) causes an inflammatory acne that is characterized by massive neutrophilic infiltration. IL-8 is thought to play an important role in the pathophysiology of P. acnes, although the mechanisms by which P. acnes up-regulates the release of IL-8, a neutrophilic chemokine, from target cells is not well understood. In this study, we investigated the mechanisms through which heat-killed P. acnes induces IL-8 production in THP-1 cells (a human monocytic cell line). We found that P. acnes is able to directly induce IL-8 production and IL-8 mRNA expression in human monocytic cells in a dose- and time-dependent manner through a mechanism requiring transcription factor NF-kappaB activation. Additionally, P. acnes-induced IL-8 secretion was inhibited by roxithromycin, a macrolide antibiotic, and its inhibitory effect seemed to be partially associated with the inhibition of P. acnes-induced NF-kappaB activation. This is the first study to show that NF-kappaB activation is involved in the IL-8 production of monocytic cells stimulated by P. acnes.

The comedo skin reaction to radiotherapy

A 50-year-old man had a maxillectomy and post-operative radiotherapy for squamous carcinoma of the maxilla. The acute skin reaction merged at 2 months into a chronic comedo-type acneiform skin reaction in the irradiated area. Previous literature on this reaction to radiation is reviewed. The reaction is rare and occurs mostly in the head and neck area, more commonly in patients who have received acneigenic drugs, and with a latent period of between 2 weeks and 6 months from completion of radiotherapy. The pathogenesis of acne is discussed and a mechanism of post-irradiation acne is suggested.

The vellus hair follicle in acne: hair growth and sebum excretion

In this study we investigated the activity of the vellus hair follicle in acne. Hair growth and sebum excretion in vellus hair follicles were measured on the forehead and back of men, and on the forehead, cheek, and back of women with acne. Hair growth was assessed by computerized image analysis (phototrichogram), and sebum excretion by computer analysis using Sebutape. In patients with acne, marked differences were revealed when results were compared with recent data from healthy persons. In particular, the mean growth rate of vellus hairs was higher, whereas the percentage of anagen hairs was lower, and the duration of the anagen phase shorter in patients with acne than in healthy individuals. Hair growth and sebum excretion depended significantly (P < 0.01) on the anatomical site (forehead 414 hairs/cm2, 0.053 mm/day, 34%; back 93 hairs/cm2, 0.16 mm/day, 21%). In addition, analysis of hair growth revealed significantly higher values in females than in males for (i) percentage of anagen hairs (P > 0.01), (ii) for vellus hair length (P < 0.05), and (iii) for the duration of the anagen phase (P < 0.01). The present study demonstrates that the activity of the vellus hair follicle is influenced by acne, and vice versa, and therefore its role in the aetiopathogenesis of acne should be reconsidered.

A comparative study of gluconolactone versus benzoyl peroxide in the treatment of acne

Alpha hydroxy acids (AHA's) or "fruit acids" are a special group of organic acids found in many natural foods. They have been described in the literature for the treatment of a number of conditions in which abnormal keratinization consistently contributes to pathogenesis. These include the icthyoses, warts, psoriasis, eczema and acne. We have performed a double-blind clinical trial on 150 patients to evaluate the efficacy and skin tolerance of the alpha hydroxy acid gluconolactone 14% in solution (Nuvoderm lotion) in the treatment of mild to moderate acne when compared with its vehicle (placebo) and 5% benzoyl peroxide lotion. The results of this study showed that both gluconolactone and benzoyl peroxide had a significant effect in improving patients' acne by reducing the number of lesions (inflamed and non-inflamed). Furthermore, fewer side-effects were experienced by patients treated with gluconolactone when compared with benzoyl peroxide.

A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne

Tea-tree oil (an essential oil of the Australian native tree Melaleuca alternifolia) has long been regarded as a useful topical antiseptic agent in Australia and has been shown to have a variety of antimicrobial activities; however, only anecdotal evidence exists for its efficacy in the treatment of various skin conditions. We have performed a single-blind, randomised clinical trial on 124 patients to evaluate the efficacy and skin tolerance of 5% tea-tree oil gel in the treatment of mild to moderate acne when compared with 5% benzoyl peroxide lotion. The results of this study showed that both 5% tea-tree oil and 5% benzoyl peroxide had a significant effect in ameliorating the patients' acne by reducing the number of inflamed and non-inflamed lesions (open and closed comedones), although the onset of action in the case of tea-tree oil was slower. Encouragingly, fewer side effects were experienced by patients treated with tea-tree oil.

Tetracycline and 13-cis-retinoic acid inhibit production and activity of granulocyte activating factor (GAF) from Propionibacterium acnes

The aim of this study was to evaluate different treatment schedules on release or activity of a granulocyte activating factor (GAF) from Propionibacterium acnes. Incubation of P. acnes in physiological saline (30 min, 37 degrees C) resulted in release of a soluble factor that elicited considerable chemiluminescence response and chemotactic stimulus on human granulocytes. Pretreatment of the microorganisms with subinhibitory concentrations of tetracycline or incubation of granulocytes with 13-cis-retinoic acid significantly reduced the activating potency of GAF on these phagocytic cells. Since GAF was considered to be one of the stimuli for inflammation in acne vulgaris, administration of tetracycline and 13-cis-retinoic acid appears to be an adequate therapy.

Acne vulgaris associated with a latissimus dorsi musculocutaneous island flap

A case is presented of the development of acne vulgaris in the skin island of a latissimus dorsi musculocutaneous flap used for breast reconstruction. The patient had acne scarring of the back but had had no active acne for twenty-five years. The latissimus dorsi musculocutaneous island flap is commonly used in breast reconstruction. The development of acne in association with skin flaps has not been described before and we speculate as to its cause.

Pyoderma faciale: a clinical study of twenty-nine patients

Pyoderma faciale is a distinctive entity. Twenty-nine patients with this process were seen in the Mayo Clinic from 1969 to 1980. Twenty-seven patients had follow-up that ranged from 1 month to 11 years, and twenty-two had follow-up of 3 years or more. Clinical features that characterize the patients were (1) female predominance, (2) onset later than teenage acne vulgaris, generally at 19 to 40 years of age, (3) rapid onset and progression, (4) facial involvement with sparing of the back and chest, (5) cysts, swelling, and purulent drainage with a lack of comedones, and (6) paucity of systemic complaints. Patients were treated with multiple forms of therapy simultaneously, often including Vleminckx packs, oral antibiotics, incision and drainage, ultraviolet B, and intralesional steroids. Of twenty-five patients available for follow-up at 1 year, twenty-three had achieved remission, though fifteen patients required ongoing treatment to maintain optimal control. Twenty-three patients had scarring as a sequela. Patients with pyoderma faciale represent a subset of patients with acne in whom the outlook is favorable with appropriate therapy.

Sex, constancy, and skin bacteria

Quantitative studies of the aerobic flora of seven skin sites in 16 volunteers were repeated after 3 months. The total aerobic densities of the sites differed, male carried more organisms than females and also more biotypes. Qualitative differences in the flora could be detected.

The effect of antimicrobial agents on leukocyte chemotaxis

The effects of several chemotherapeutic agents on the chemotaxis of human leukocytes were studied in an in vitro system using a Sykes-Moore chamber and a double-filter technique. Chemotactic factor was generated by the interaction of normal human serum and zymosan. At concentrations comparable to and below therapeutic blood levels, tetracycline HCl, erythromycin base and clindamycin HCl were all inhibitory, causing marked suppression of leukocyte chemotaxis and slight reduction of random migration. Penicillin G-Na, dapsone, and sulfapyridine did not alter white cell motility at the concentrations of drug tested. It is postulated that the capacity of some of these agents to inhibit leukocyte chemotaxis may account, in part, for their efficacy in inflammatory skin diseases such as acne vulgaris.

Use of bacteriophage typing to distinguish Propionibacterium acne types I and II

Strains of serotypes I and II of Propionibacterium were compared for phage sensitivity. The two serotypes could be distinguished by using a typing set consisting of 16 bacteriophages at concentrations that demonstrated selective lysis of serotype I or II bacterial strains. Seven phage types were found; three were composed exclusively of serotype I, and four were exclusively composed of serotype II organisms. Generally, serotype I strains were more sensitive to phage lysis than were serotype II strains. No correlation was found between phage type and site of isolation.

Use of litmus milk agar for presumptive identification of cutaneous propionibacteria

Presumptive identification of cutaneous propionibacteria can be achieved with litmus milk agar as medium.

Comedo formation in acne

Comedones contain a considerable quantity of water. In some cases a water content of more than 40% can be detected. The comedo consists of two parts, an inner nucleus built up to unorganized materials and a capsule with concentrically arranged shells. The material of the nucleus contains small scales produced by normal keratinization. The materials of the capsule consists of larger scales, which result from hyperkeratosis. The nucleus of the comedo seems to be identical with the early comedo. A similar structure can be formed in vitro by adding water to sebum. Microorganisms have optimal growth conditions in the early comedo.

The localization and distribution of gram-positive cocci in normal skin and in lesions of acne vulgaris

The localization of gram-positive cocci in the normal skin and in the lesions of acne vulgaris was investigated using fluorescein-labeled antiserum raised to gram-positive, coagulase-negative cocci. The cocci were found in 10 of 19 specimens from normal facial skin and in 3 of 11 specimens from the normal skin of the rest of the body. The bacteria were found mostly in the openings of follicles, but in 6 of 10 facial skin specimens, they were also present deeply in the lumina of the dilated sebaceous follicles near the sebaceous glands. Cocci were found in 5 of 6 noninflammatory acne comedones. In inflammatory acne they were demonstrated not only in the follicular canals but also sparsely in the infiltrate surrounding the follicles.