Expanding the microcomedone theory and acne therapeutics: Propionibacterium acnes biofilm produces biological glue that holds corneocytes together to form plug

The Propionibacterium acnes biofilm has previously been shown to exist via genomic studies and to make a biological glue which allows for adherence to follicular walls. This gylcocalyx polymer secreted by P acnes also finds its way into sebum composition where it causes the adhesiveness of keratinocytes leading to comedones. An appreciation of P acnes biofilms and secretions has implications in immunogenicity of the organism, clinical course of acne, and therapy for comedonal and inflammatory acne.     

痤疮丙酸杆菌与痤疮

痤疮丙酸杆菌的结构、分布和生理特点决定其在痤疮发病中的重要作用,尤其与痤疮的炎症损害及严重程度密切有关.目前,针对痤疮丙酸杆菌的痤疮治疗方法众多,包括应用四环素类、克林霉素、红霉素等治疗和过氧苯甲酰或5-氨基酮戊酸光动力疗法等.由于耐药性痤疮丙酸杆菌的出现,抗生素与非抗生素类药物的联合疗法已被证明为最佳治疗手段.痤疮丙酸杆菌全部基因组序列的测定使针对痤疮的菌苗疗法成为可能.     

痤疮丙酸杆菌与痤疮

痤疮丙酸杆菌的结构、分布和生理特点决定其在痤疮发病中的重要作用,尤其与痤疮的炎症损害及严重程度密切有关.目前,针对痤疮丙酸杆菌的痤疮治疗方法众多,包括应用四环素类、克林霉素、红霉素等治疗和过氧苯甲酰或5-氨基酮戊酸光动力疗法等.由于耐药性痤疮丙酸杆菌的出现,抗生素与非抗生素类药物的联合疗法已被证明为最佳治疗手段.痤疮丙酸杆菌全部基因组序列的测定使针对痤疮的菌苗疗法成为可能.     

Antibiotic susceptibility of Propionibacterium acnes isolated from acne vulgaris in Korea

Propionibacterium acnes plays an important role in the development of acne, and inflammatory lesions are improved by antibiotics. Long-term use of antibiotics may result in development of resistant strains and treatment failure. The aim of the present study was to investigate the isolation rate of P. acnes and to evaluate its antibiotic susceptibility to widely used antibiotics in acne in Korea. Among 46 patients, 31 P. acnes strains were cultured. Isolated P. acnes was measured for minimum inhibitory concentration (MIC) of tetracycline, doxycycline, minocycline, erythromycin and clindamycin using an Epsilometer test. Age, disease duration and previous history of antibiotic therapy for acne were compared in relation to the MIC. The mean MIC of tetracycline, minocyclines, doxycycline, clindamycin and erythromycin were all below the breakpoint of antibiotic resistance. The patients with acne vulgaris with disease duration of more than 2 years documented higher MIC values in doxycycline, erythromycin, and clindamycin than those of less than 2 years. The patients who were previously treated with topical or systemic antibiotics showed higher MIC in doxycycline. Antibiotic resistance of P. acnes is still low in Korea, but at this point, there is an increasing trend of MIC. Caution and acknowledgement of increased risk of antibiotic resistant P. acnes should be advised in acne antibiotic treatment to minimize and avoid the emergence of the resistant strain.     

The evolving role of Propionibacterium acnes in acne

Propionibacterium acnes is a member of the resident cutaneous flora. Sebaceous follicles involved in acne are characterized by the accumulation of abnormally desquamated corneocytes and excess sebum-the microcomedo. This environment provides ideal growth conditions for P acnes. Several orders of magnitude level of P acnes are found in microcomedos. P acnes produces a variety of chemotactic factors and proinflammatory molecules that are responsible for the inflammatory phase of acne. Antibiotic therapy works by reducing the viable number of P acnes as well as by reducing the production of inflammatory stimuli. Antibiotic therapy has been a mainstay of treatment for more than 30 years. In the last decade, decreased sensitivity to antibiotics has developed and clinical resistance has been described. This development threatens the usefulness of antibiotic therapy in the future.     

Community-based study of acne vulgaris in adolescents in Singapore

BACKGROUND: There are few studies on the prevalence of acne vulgaris among Asian teenagers. OBJECTIVES: To determine the epidemiology of acne in teenagers in Singapore. METHODS: A community-based cross-sectional study in 1045 adolescents aged 13-19 years. RESULTS: Of these respondents, 88% identified themselves as having acne. Eight hundred and six of these respondents were examined by a dermatologist, and 51.4% were classified as having mild acne, 40% moderate acne and 8.6% severe acne. Isolation of Propionibacterium acnes was attempted in 262 subjects. Cultures were positive in 174 subjects, giving an isolation rate of 66.4%. Antibiotic-resistant strains of P. acnes were detected in 26 isolates (14.9%). Eleven of these 26 subjects (42%) had previously been treated or were presently on antibiotic treatment for acne, but the other 58% of students who had antibiotic-resistant strains of P. acnes did not give a history of prior antibiotic therapy. Teenagers expressed psychological distress over acne, and believed that hormonal factors, diet and hygiene were important factors in causing acne. CONCLUSIONS: There is a need for accessible, accurate education on acne and its appropriate treatment.     

Propionibacterium acnes resistance to antibiotics in acne patients

The minimal inhibitory concentration (MIC) of Propionibacterium acnes in seventy-five acne patients receiving long-term antibiotic therapy demonstrated the emergence of resistant strains. The mean MIC in thirty-three patients receiving long-term tetracycline was four to five times higher than that found in control groups of acne patients not receiving antibiotic therapy and controls free of acne. The average MIC for erythromycin was more than 100 times higher in those receiving long-term antibiotic therapy. In a second group of sixty-two patients, the clinical course and number of P. acnes were correlated with the presence of "resistant strains" defined as P. acnes with a tenfold increase in MIC to tetracycline or erythromycin. Patients with resistant strains had higher counts of P. acnes and clinically were not doing as well as those with sensitive strains.     

The bacteriology of acne vulgaris and antimicrobial susceptibility of Propionibacterium acnes and Staphylococcus epidermidis isolated from acne lesions

We examined the species of bacteria aerobically and anaerobically isolated from 30 acne lesions and determined antimicrobial susceptibilities of Propionibacterium acnes (P. acnes) and Staphylococcus epidermidis (S. epidermidis) using nine antimicrobial agents. Among the bacteria isolated, S. epidermidis was most dominant. Both P. acnes and S. epidermidis were isolated from half of the acne lesions. The MIC of seven antimicrobials (ampicillin, erythromycin, roxithromycin, clindamycin, tetracycline, minocycline, nadifloxacin) against P. acnes was under 3.13 micrograms/ml. There were very few resistant strains of P. acnes, but many of S. epidermidis. More than 30% of the S. epidermidis isolates were resistant to erythromycin, roxithromycin, and clindamycin. After long-term systemic antibiotic therapy, the resistant strains of S. epidermidis increased, but P. acnes resistance was still limited. When we use antimicrobial agents for the treatment of acne, it should be noticed that not only P. acnes but also S. epidermidis in the acne lesions may acquire resistance to antimicrobials.     

Lymphocyte transformation in subjects with nodulo-cystic acne

Patients with severe nodulo-cystic acne are known to have elevated serum antibody levels and increased immediate hypersensitivity reactions to Propionibacterium acnes. This organism is the predominant bacterium in normal pilosebaceous follicles of human skin, and can be consistently isolated from pustular lesions in acne. Previously it had been observed that delayed cutaneous hypersensitivity reactions to P. acnes were negative in patients with acne. The present study investigated the proliferative response of lymphocytes from patients with nodulo-cystic acne to phytohaemagglutinin (PHA) and P. acnes antigen stimulation. The response to PHA stimulation was within normal limits. The response to P. acnes antigen showed a significant increase over control values obtained by testing lymphocytes from acne-free subjects. Thus cell mediated immunity to P. acnes may be present in subjects with severe inflammatory acne. These findings raise the possibility that reactions to P. acnes may contribute to intensifying the inflammatory response in acne lesions.     

Benzoyl Peroxide-Based Combination Therapies for Acne Vulgaris

Benzoyl peroxide, with its broad-spectrum antimicrobial activity, is among the most widely used topical agents in the treatment of inflammatory acne vulgaris. Benzoyl peroxide is marketed either alone or in combination with other topical antibiotics; namely, erythromycin and clindamycin. The combination products confer specific advantages over benzoyl peroxide alone, particularly in decreasing the in vivo follicular counts of Propionibacterium acnes, the anaerobic bacterium implicated in the pathogenesis of acne. In addition, the topical treatment of inflammatory acne has been complicated by the development of P acnes resistance to topical erythromycin and clindamycin. Combination products containing benzoyl peroxide and the topical antibiotics have been shown to both: (i) prevent the development of antibiotic resistance in acne patients; and (ii) confer significant clinical improvement to patients who have already developed antibiotic resistance.     

我国痤疮患者皮损中痤疮丙酸杆菌对抗生素耐药性的Meta分析

目的：系统评价我国痤疮患者的皮损分离的痤疮丙酸杆菌(P.acnes)对抗生素的耐药情况，为痤疮抗生素合理治疗提供临床依据。方法：计算机网络检索中国知网(CNKI)、中文科技期刊文数据库(VIP)、万方数据库和PubMed中的相关研究，收集痤疮皮损分离痤疮丙酸杆菌对四环素类、大环内酯类等抗菌药物耐药率的相关研究，对符合纳入标准研究资料进行提取，采用R语言3.3.2 Meta程序包进行Meta分析。结果：共纳入文章13篇，合计1770例痤疮患者，共分离痤疮丙酸杆菌合计1259株。对我国P.acnes的抗生素耐药率进行单组率Meta分析，结果显示P.acnes对红霉素、克拉霉素、阿奇霉素耐药率分别为：45%（95% CI 0.35～0.58)，74%（95% CI 0.51～0.89)，59%（95% CI 0.33～0.84)；对米诺环素、多西环素、四环素耐药率分别为：2%（95% CI 0.00～0.07)，6%（95% CI 0.00～0.26)，8%（95% CI 0.00～0.24)；对甲硝唑耐药率为96%（95% CI 0.80～1.00）。不同抗生素之间存在交叉耐药。结论：我国痤疮患者皮损分离的P.acnes对大环内酯类及甲硝唑耐药率高，对四环素类、喹诺酮类抗生素较为敏感，其中以米诺环素敏感性最高。     

Topical aminolaevulinic acid-photodynamic therapy for the treatment of acne vulgaris: a study of clinical efficacy and mechanism of action

BACKGROUND: Acne affects 83-95% of 16-year-olds of both sexes, and many seek help from a clinician. Emerging problems with conventional acne treatments, specifically antibiotic resistance of Propionibacterium acnes and fears over the safety and tolerance of oral isotretinoin, create a demand for novel treatment modalities in acne. OBJECTIVES: To study the efficacy of aminolaevulinic acid-photodynamic therapy (ALA-PDT) in the treatment of acne and to identify the mode of action, looking specifically at the effects on surface numbers of P. acnes and on sebum excretion. METHODS: Ten patients (nine men and one woman, age range 16-40 years) with mild to moderate acne on their backs were recruited. Each patient's back was marked with four 30-cm2 areas of equal acne severity. Each site was then randomly allocated to either ALA-PDT treatment, light alone, ALA alone or an untreated control site. At baseline, numbers of inflammatory and noninflammatory acne lesions were counted, sebum excretion measured by Sebutapes (CuDerm, Dallas, TX, U.S.A.) and surface P. acnes swabs performed. ALA cream (20% in Unguentum Merck) was applied under occlusion to the ALA-PDT and ALA alone sites for 3 h. Red light from a diode laser was then delivered to the ALA-PDT and light alone sites (635 nm, 25 mW cm(-2), 15 J cm(-2)). Each patient was treated weekly for 3 weeks. At each visit acne lesion counts were performed and 3 weeks following the last treatment sebum excretion rates and P. acnes swabs were repeated. RESULTS: There was a statistically significant reduction in inflammatory acne lesion counts from baseline after the second treatment at the ALA-PDT site but not at any of the other sites. No statistically significant reduction in P. acnes numbers or sebum excretion was demonstrated at any sites including the ALA-PDT site. CONCLUSIONS: ALA-PDT is capable of clinically improving acne. An alternative mode of action for ALA-PDT other than direct damage to sebaceous glands or photodynamic killing of P. acnes is suggested from the results of this study.     

Photodynamic therapy for acne vulgaris: a pilot study of the dose-response and mechanism of action

Acne vulgaris does not always respond to conventional therapy. Photodynamic therapy (PDT) has been proposed as a treatment option. The aim of this study was to determine the optimal light dose for effective PDT treatment of acne and to investigate whether PDT reduces sebum excretion and the amount of Propionibacterium acnes. Fifteen patients (9 men, 6 women, age range 16-44 years, mean age 25 years) with mild to severe acne were enrolled in an open, unblinded study. Aminolaevulinic acid cream (20% in Unguentum Merck) was applied on two circular areas 3 h before PDT. The areas of investigation were irradiated with red light (635 nm) from a Waldman PDT 1200 lamp. Ten patients with facial acne were treated with a light dose of 50 J/cm(2) on the right cheek and 30 J/cm(2) on the left cheek. Five patients with acne on their back were treated either with 50 J/cm(2) or with 70 J/cm(2). Clinical follow-up was performed for at least 10 weeks. In the patients with facial acne, sebum excretion was determined before PDT and at every follow-up visit. The amount of P. acnes was measured in a skin surface biopsy using a cyano-acrylate polymer to extract the content of the sebaceous follicles. In 9 patients with facial acne the improvement of lesions was the same for the two light doses. According to the patients' own assessment, 8 improved after PDT (p=0.02). No difference was found between the two doses in patients with acne on the back. Hyperpigmentation was more common at higher doses of light, and pain was experienced more often by the patients when higher doses were used. No significant reduction in P. acnes or sebum excretion was found at any time after PDT. It is concluded that PDT could be an alternative treatment of acne lesions. The lowest possible light dose should be used for minimal side-effects. Other mechanisms of action for PDT than eradication of P. acnes and sebosuppression should be considered.     

痤疮的抗生素治疗及耐药现状

痤疮丙酸杆菌在痤疮发生、发展过程中起着重要作用,外用或口服抗生素对痤疮炎性皮损有肯定疗效。然而随着抗生素的广泛使用,耐药问题日益严峻,研究表明超过50%的痤疮丙酸杆菌出现了耐药,尤其是对大环内酯类抗生素。本文对抗生素治疗痤疮的作用机理与使用现状、耐药机制与耐药现状进行综述。     

Effects of Roxithromycin on the production of lipase and neutrophil chemotactic factor by Propionibacterium acnes

BACKGROUND: The macrolide antibiotic roxithromycin is effective against acne associated with inflammation, but the mechanism by which this is achieved has not been clarified. OBJECTIVE: We studied the effects of roxithromycin on the production of lipase and neutrophil chemotactic factor by Propionibacterium acnes in vitro. RESULTS: Roxithromycin significantly inhibited the production of lipase and neutrophil chemotactic factor by P. acnes at a concentration one eighth of the MIC, at which the growth curve of P. acnes is not affected. CONCLUSION: One mechanism of the effectiveness of roxithromycin in acne therapy is thought to be the inhibition of bacterial lipase and neutrophil chemotactic factor production by P. acnes.     

Granulysin-derived peptides demonstrate antimicrobial and anti-inflammatory effects against Propionibacterium acnes

Propionibacterium acnes is a key therapeutic target in acne, yet this bacterium has become resistant to standard antibiotic agents. We investigated whether the human antimicrobial protein granulysin is a potential candidate for the treatment of acne. Granulysin and synthetic granulysin-derived peptides possessing a helix-loop-helix motif killed P. acnes in vitro. Modification of a helix-loop-helix peptide, 31-50, by substitution of a tryptophan for the valine at amino acid 44 (peptide 31-50v44w) to increase its interaction with bacterial surfaces also increased its antimicrobial activity. Moreover, when synthesized with D- rather than L-type amino acids, this peptide (D-31-50v44w) became less susceptible to degradation by proteases and more effective in killing P. acnes. Granulysin peptides were bactericidal, demonstrating an advantage over standard bacteriostatic antibiotics in their control of P. acnes. Moreover, peptide D-31-50v44w killed P. acnes in isolated human microcomedone preparations. Importantly, peptides 31-50, 31-50v44w, and D-31-50v44w also have potential anti-inflammatory effects, as demonstrated by suppression of P. acnes-stimulated cytokine release. Taken together, these data suggest that granulysin peptides may be useful as topical therapeutic agents, providing alternatives to current acne therapies.     

Antibodies elicited by inactivated propionibacterium acnes-based vaccines exert protective immunity and attenuate the IL-8 production in human sebocytes: relevance to therapy for acne vulgaris

Propionibacterium acnes is a key pathogen involved in the progression of inflammation in acne vulgaris. We examined whether vaccination against P. acnes suppressed P. acnes-induced skin inflammation. Inactivation of P. acnes with heat was employed to create a P. acnes-based vaccine. Intranasal immunization in mice with this inactivated vaccine provoked specific antibodies against P. acnes. Most notably, immunization with inactivated vaccines generated in vivo protective immunity against P. acnes challenge and facilitated the resolution of ear inflammation in mice. In addition, antibodies elicited by inactivated vaccines effectively neutralized the cytotoxicity of P. acnes and attenuated the production of proinflammatory cytokine IL-8 in human sebocyte SZ95 cells. Intranasal immunization using heat-inactivated P. acnes-based vaccines provided a simple modality to develop acne vaccines. These observations highlight the concept that development of vaccines targeting microbial products may represent an alternative strategy to conventional antibiotic therapy.     

All-trans retinoic acid shifts Propionibacterium acnes-induced matrix degradation expression profile toward matrix preservation in human monocytes

Propionibacterium acnes is a critical component in the pathogenesis of acne vulgaris, stimulating the production of various inflammatory mediators, such as cytokines and chemokines, important in the local inflammatory response found in acne. This study explored the role of P. acnes and its ability to induce matrix metalloproteinases (MMPs) in primary human monocytes and how this induction is regulated by retinoids. MMP-1- and MMP-9-expressing cells were present in perifollicular and dermal inflammatory infiltrates within acne lesions, suggesting their role in acne pathogenesis. In vitro, we found that P. acnes induced MMP-9 and MMP-1 mRNA, and the expression of MMP-9, but not of MMP-1, was found to be Toll-like receptor 2-dependent. P. acnes induced the mRNA expression of tissue inhibitors of metalloproteinase (TIMP)-1, the main regulator of MMP-9 and MMP-1. Treatment of monocytes with all-trans retinoic acid (ATRA) significantly decreased baseline MMP-9 expression. Furthermore, co-treatment of monocytes with ATRA and P. acnes inhibited MMP-9 and MMP-1 induction, while augmenting TIMP-1 expression. These data indicate that P. acnes-induced MMPs and TIMPs may be involved in acne pathogenesis and that retinoic acid modulates MMP and TIMP expression, shifting from a matrix-degradative phenotype to a matrix-preserving phenotype.     

Acne and Propionibacterium acnes

The involvement of microorganisms in the development of acne has a long and checkered history. Just over 100 years ago, Propionibacterium acnes (then known as Bacillus acnes) was isolated from acne lesions, and it was suggested that P. acnes was involved in the pathology of the disease. The 1960s saw the use of antibiotics to treat acne, and the consequent clinical success combined with reductions in P. acnes gave new impetus to the debate. Over the past two decades, the inevitable emergence of antibiotic-resistant strains of P. acnes as a consequence of acne therapy not only has reopened the debate as to the role of P. acnes in acne, but also has created some serious health care implications.     

痤疮丙酸杆菌生物膜体外模型的成膜规律研究

目的：通过构建痤疮丙酸杆菌（P.acne）生物膜,探索其成膜规律。方法：体外构建痤疮丙酸杆菌生物膜模型,使用激光共聚焦显微镜、XTT细胞活力测定法动态检测生物膜在不同时间点（0、1、2、3、4、5、6、7、8、10、15和20 d）的结构、厚度及活力情况。结果：在20天时间内菌株经历了生物膜的形成、播散、再形成的过程。第8天生物膜的厚度和活力动态均达到最大值(29.8±2.167)μm和0.620±0.063。结论：痤疮丙酸杆菌生物膜体外培养8天达最佳成熟状态。