Inhibitory effects of Fortunella japonica var. margarita and Citrus sunki essential oils on nitric oxide production and skin pathogens

A number of essential oils from citrus peels are claimed to have biological activities. Citrus peel, called 'Jin-Pi', is used in traditional medicine for digestion, severe cold, and fever. However, the antibacterial activities against skin pathogens and anti-inflammatory effects of the essential oils of Citrus sunki (JinGyul) and Fortunella japonica var. margarita (GumGyul) have not yet been described. Therefore, in this study, the essential oils of the citrus species C. sunki (CSE) and F. japonica var. margarita (FJE), both native to the island of Jeju, Korea, were examined for their anti-inflammatory and antimicrobial activities against skin pathogens. Four human skin pathogenic microorganisms, Staphylococcus epidermidis CCARM 3709, Propionibacterium acnes CCARM 0081, Malassezia furfur KCCM 12679, and Candida albicans KCCM 11282, were studied. CSE and FJE exhibited strong antimicrobial activity against most of the pathogenic bacteria and yeast strains that were tested. Interestingly, CSE and FJE even showed antimicrobial activity against antibiotic-resistant S. epidermidis CCARM 3710, S. epidermidis CCARM 3711, P. acnes CCARM9009, and P. acnes CCARM9010 strains. In addition, CSE and FJE reduced the lipopolysaccharide (LPS)-induced secretion of nitric oxide (NO) in RAW 264.7 cells, indicating that they have anti-inflammatory effects. We also analysed the chemical composition of the oils by gas chromatography-mass spectrometry (GC-MS) and identified several major components, including dl-limonene (68.18%) and beta-myrcene (4.36%) for CSE, and dl-limonene (61.58%) and carvone (6.36%) for FJE. Taken together, these findings indicate that CSE and FJE have great potential to be used in human skin health applications.

Free radical scavenging and anti-acne activities of mangosteen fruit rind extracts prepared by different extraction methods

The ethanol extracts of mangosteen fruit rinds prepared by several extraction methods were examined for their contents of bioactive compounds, DPPH-scavenging activity, and anti-acne producing bacteria against Propionibacterium acnes and Staphylococcus epidermidis. The dried powder of the fruit rind was extracted with 95% ethanol by maceration, percolation, Soxhlet extraction, ultrasonic extraction, and extraction using a magnetic stirrer. Soxhlet extraction promoted the maximum contents of crude extract (26.60% dry weight) and alpha-mangostin (13.51%, w/w of crude extract), and also gave the highest anti-acne activity with MIC 7.81 and 15.63 microg/mL and MBC 15.53 and 31.25 microg/mL against P. acnes and S. epidermidis, respectively. Ethanol 70% and 50% (v/v) were also compared in Soxhlet extraction. Ethanol 50% promoted the extract with maximum amounts of total phenolic compounds (26.96 g gallic acid equivalents/100 g extract) and total tannins (46.83 g tannic acid equivalents/100 g extract), and also exhibited the most effective DPPH-scavenging activity (EC(50) 12.84 microg/mL). Considering various factors involved in the process, Soxhlet extraction carried a low cost in terms of reagents and extraction time. It appears to be the recommended extraction method for mangosteen fruit rind. Ethanol 50% should be the appropriate solvent for extracting free radical-scavenging components, phenolic compounds, and tannins, while 95% ethanol is recommended for extraction of alpha-mangostin, a major anti-acne component from this plant.

Anti-acne-inducing bacterial activity of mangosteen fruit rind extracts

OBJECTIVE

The aims of this study were to determine the most effective solvent extract of mangosteen, anti-acne- inducing bacterial activity and the amount of alpha-mangostin, a major active component in each mangosteen fruit rind extract, using high-performance liquid chromatography (HPLC).

MATERIALS AND METHODS

The fruit rinds of mangosteen were extracted with hexane, dichloromethane, ethanol and water. The extracts were tested for antibacterial activity against bacteria that induce acne, including Propionibacterium acnes and Staphylococcus epidermidis. Thin-layer chromatographic autobiography against these bacteria was also performed for each extract, while the alpha-mangostin content was analyzed using a validated HPLC method.

RESULTS

The dichloromethane extract exhibited the strongest antibacterial effect with minimum inhibitory concentration values for both bacterial species at 3.91 microg/ml, while the minimum bactericidal concentration values against P. acnes and S. epidermidis were 3.91 and 15.63 microg/ml, respectively. Thin-layer chromatographic autobiography indicated that alpha-mangostin was present in all extracts, except the water extract, and is a major active component against both P. acnes and S. epidermidis. Using HPLC, the dichloromethane extract yielded the highest content (46.21% w/w) of alpha-mangostin followed by the ethanol extract (18.03% w/w), the hexane extract (17.21% w/w) and the water extract (0.54% w/w).

CONCLUSIONS

Dichloromethane extract exhibited the strongest anti-acne-inducing bacterial effect and this extract yielded the highest amount of alpha-mangostin.

Evaluation of the antibacterial activity of rhapontigenin produced from rhapontin by biotransformation against Propionibacterium acnes

Biotransformation is often used to improve chemical activity. We evaluated the antimicrobial activity of rhapontigenin, converted from rhapontin after treatment with Pectinex. Rhapontigenin showed 4-16 times higher antimicrobial activity than rhapontin. Activity was higher against Gram positive strains than Gram negative strains. Minimum inhibitory concentrations (MICs) of rhapontigenin, retinol, and five antibiotics were determined by microbroth dilution method for antibiotic-sensitive and -resistant Propionibacterium acnes. We also investigated the in vitro antibacterial activity of rhapontigenin in combination with antibiotic against antibiotic-resistant P. acnes. The antibiotic combination effect against resistant P. acnes was studied by checkerboard method. The combination formulations (rhapontigenin and clindamycin, retinol and clindamycin) showed synergic effects on the inhibition of the growth of clindamycin-resistant P. acnes. It is predictable that the combination of antibiotics with rhapontigenin is helpful to treat acne caused by antibiotic resistant P. acnes. The antibacterial activity of rhapontigenin was enhanced by biotransformation.

Comparative efficacy and safety results of two topical combination acne regimens

Combination therapy has become the standard for the management of acne, particularly for moderate-to-severe cases. Among these combinations, those regimens containing benzoyl peroxide (BPO), clindamycin and a retinoid have been used frequently as they address most aspects of acne pathogenesis. This study compares the efficacy and safety of two common topical treatment regimens in the treatment of a moderate to severe facial acne vulgaris: fixed-combination gel containing BPO 5% and clindamycin 1% (BPO/C) plus tretinoin microsphere gel 0.04% (RAM) versus a regimen of a fixed-combination gel containing clindamycin phosphate 1.2% and tretinoin 0.025% (CPT) plus a once-daily BPO 5% wash. While both regimens were safe and effective, regimen BPO/C+RAM yielded a more rapid onset of effect versus regimen CPT+BPO against both non-inflammatory and inflammatory lesions. Both treatment regimens were well-tolerated.

Advancement in benzoyl peroxide-based acne treatment: methods to increase both efficacy and tolerability

BACKGROUND

Antibiotic resistance of Propionibacterium acnes (P. acnes) is a growing phenomenon in the wake of widespread use of topical and systemic antibiotics for acne vulgaris. Benzoyl peroxide has a proven track record of safety and efficacy, and can decrease reliance on antibiotics in the treatment of acne.

PURPOSE

To review the literature for methods to increase the efficacy and tolerability of benzoyl peroxide (BPO).

METHODS

A PubMed literature search was done using the terms "benzoyl peroxide," "vehicle," "mechanism," and "delivery system." Relevant papers were reviewed for methods of increasing BPO efficacy and tolerability.

RESULTS

BPO in concentrations of 2.5%, 5% and 10% are equally effective at treating inflammatory acne. However, higher concentrations are associated with more adverse effects. The efficacy of BPO may be enhanced by the presence of Vitamin E and tertiary amines. BPO is also more efficacious if used in combination with topical retinoids than as a monotherapy. Novel vehicles including a microparticle delivery system and those with a hydrophase or urea base increase the tolerability of BPO without sacrificing efficacy.

CONCLUSION

Benzoyl peroxide has a proven track record of safety and efficacy for the treatment of acne. Recent discoveries have provided new methods of increasing the efficacy and tolerability of topical BPO, making it useful as monotherapy for mild acne or as an adjunct in the treatment of moderate to severe acne vulgaris.

In vitro activities of three synthetic peptides derived from epinecidin-1 and an anti-lipopolysaccharide factor against Propionibacterium acnes, Candida albicans, and Trichomonas vaginalis

The synthetic epinecidin-1(22-42) peptide was derived from positions 22-42 of Epinephelus coioides epinecidin-1. The synthetic SALF(55-76) cyclic peptide (csSALF(55-76)) and SALF(55-76) linear peptide (lsSALF(55-76)) contained sequences from positions 55 to 76 of the Penaeus monodon anti-lipopolysaccharide factor (ALF), respectively. We studied the in vitro activities of epinecidin-1(22-42), csSALF(55-76), and lsSALF(55-76) against Propionibacterium acnes, Candida albicans, and Trichomonas vaginalis. The minimum inhibitory concentrations (MICs) of epinecidin-1(22-42) for the test pathogen strains ranged 12.5-200 microg/ml, those of csSALF(55-76) ranged 100-200 microg/ml, and those of lsSALF(55-76) ranged 25-200 microg/ml. epinecidin-1(22-42) exhibited cytotoxicity towards P. acnes, C. albicans, and T. vaginalis (one strain of which was a metronidazole-resistant strain, while the other strain was not), suggesting that epinecidin-1 functions like a lytic peptide. Similar cytotoxicity was identified against T. vaginalis treated with the csSALF(55-76) and lsSALF(55-76) peptides. The antimicrobial activities of these peptides were confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), a viable cell count assay, and flow cytometric analysis. TEM and SEM examinations of T. vaginalis treated with these three peptides showed that severe swelling preceded cell death and breakage of the outer membrane, and the intracellular inclusion was found to have effluxed extracellularly. This phenomenon was also found with epinecidin-1(22-42) treatment of P. acnes and C. albicans. Our results suggest that the epinecidin-1(22-42), csSALF(55-76), and lsSALF(55-76) peptides may be good candidates for treating trichomoniasis, and epinecidin-1(22-42) may have potential as a drug supporting therapy for acne and candidiasis.

The novel anti-Propionibacterium acnes compound, Sargafuran, found in the marine brown alga Sargassum macrocarpum

We screened extracts of 342 species of marine algae collected from Japanese coastlines for antibacterial activity against Propionibacterium acnes, and found a novel antibacterial compound, which we named Sargafuran, from the MeOH extract of the marine brown alga, Sargassum macrocarpum. Sargafuran has low cytotoxicity, and the MIC against P. acnes was 15 microg ml(-1), showing a broad antibacterial activity against Gram-positive bacteria. A time-kill study showed that Sargafuran was bactericidal and completely killed P. acnes at 4 x MIC by lysing bacterial cells. These results suggest that Sargafuran might be useful as a lead compound to develop new types of anti-P. acnes substances and new skin care cosmetics to prevent or improve acne.

In vitro evaluation of antibacterial, anticollagenase, and antioxidant activities of hop components (Humulus lupulus) addressing acne vulgaris

Seven naturally derived components from hop plant (Humulus lupulus L.) extracts were tested for evaluation of biological activities affecting acne vulgaris. Five strains, Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, Kocuria rhizophila and, Staphylococcus pyogenes, were selected as the main acne-causing bacteria. Hop extracts xanthohumol and the lupulones showed strong inhibitory activities against all of the strains. Although hydrogenated derivatives did not show the same level of activity, naturally occurring xanthohumol, humulones, and lupulones all showed moderate to strong anticollagenase inhibitory activities. Antioxidant capacity was also evaluated with seven different methods based on different reactive oxygen species. Xanthohumol showed the highest activity in total oxygen radical absorbance capacity as well as singlet oxygen absorbance capacity.

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.

Antibiotic-resistant Propionibacterium acnes suppressed by a benzoyl peroxide cleanser 6%

Adding topical benzoyl peroxide (BPO) to antibiotics can reduce resistant Propionibacterium acnes in patients with acne receiving antibiotic therapy. Benzoyl peroxide often is formulated as a wash, but no published data exist regarding BPO wash formulation efficacy in reducing resistant strains of P acnes. This 3-week, open-label, single-center study evaluated the effects of BPO cleanser 6% on antibiotic-resistant P acnes populations. The study involved 30 healthy adults who were free of acne but had high facial P acnes populations (10,000 colonies/cm2 or more) resistant to erythromycin and tetracycline at 8 microg/mL or more and 2 microg/mL or more, respectively. Participants applied BPO cleanser 6% once daily. Quantitative P acnes cultures were obtained at baseline and weekly for 3 weeks. At baseline, resistance to erythromycin, tetracycline, doxycycline, minocycline, and clindamycin was present in 100% (30/30), 97% (29/30), 83% (25/30), 63% (19/30), and 100% (25/25) of participants, respectively, high-level resistance for erythromycin and tetracyclines and intermediate to high resistance for clindamycin was present in 100% (30/30), 50% (15/30), 33% (10/30), 27% (8/30), and 52% (13/25) of participants, respectively. Total P acnes counts and counts of each resistant strain decreased by approximately 1 log after 1 week of treatment, by at least 1.5 log after 2 weeks of treatment, and by at least 2 log after 3 weeks of treatment, with no differences between resistant and susceptible strains or between highly resistant and low-level resistant strains. Benzoyl peroxide cleanser 6% effectively reduced resistant P acnes populations and offers a useful therapy for controlling antibiotic resistance in patients receiving antibiotics.

Benzoyl peroxide cleansers for the treatment of acne vulgaris: status report on available data

Benzoyl peroxide (BPO) cleansers are commonly prescribed for treatment of acne vulgaris. In fact, they represent approximately half of all BPO prescriptions from dermatology practices. Data are limited on the ability of BPO cleansers to reduce counts of Propionibacterium acnes, impact on reduction and emergence of antibiotic-resistant P acnes strains, and efficacy for facial and truncal acne vulgaris. This article discusses available data on BPO cleanser formulations.

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.

CBT-SL5, a bacteriocin from Enterococcus faecalis, suppresses the expression of interleukin-8 induced by Propionibacterium acnes in cultured human keratinocytes

Propionibacterium acnes is known to play a pivotal role in the pathogenesis of acne vulgaris. CBT-SL5 is one of the antimicrobial peptides from Enterococcus faecalis SL5, and it has shown antimicrobial activity against P. acnes. The aim of this study was to investigate the anti-inflammatory effect of CBT-SL5 on the inflammation induced by P. acnes in cultured human keratinocyes. Cultured human keratinocytes derived from neonatal foreskin were treated with heatkilled P. acnes to induce inflammation, and then various concentrations of CBT-SL5 were added to the P. acnestreated keratinocytes. The mRNA expression and protein secretion of interleukin (IL)-8, an inflammation marker, was analyzed by real-time reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. We also analyzed the nuclear factor-kappa B (NF-kappaB) p65 translocation by performing immunofluorescent staining. P. acnes treatment upregulated the IL-8 mRNA expression in the keratinocytes, and this was brought about through both toll-like receptor (TLR)2 and TLR4. At the concentrations of 10, 50, and 100 ng/ml, CBT-SL5 significantly downregulated the P. acnes-induced IL-8 mRNA expression and protein production (p<0.05). At 6 h and 12 h of the treatment, CBT-SL5 significantly suppressed the P. acnesinduced IL-8 mRNA expression. Secretion of IL-8 protein was significantly reduced at 24 h. The functional inhibitory activity of CBT-SL5 was shown by CBT-SL5 suppressing the P. acnes-induced NF-kappaB translocation from the cytoplasm to the nucleus. These results demonstrated that CBT-SL5 suppressed the P. acnes-induced IL-8 expression in keratinocytes. Therefore, CBT-SL5 may be a novel anti-inflammatory treatment for acne.

Labdane-type diterpenes active against acne from pine cones (Pinus densiflora)

Bioassay-guided extraction and fractionation of the aqueous methanolic extract of the cones of Pinus densiflora (Pinaceae) afforded one new labdane-type diterpene aldehyde, 15-nor-14-oxolabda-8(17),12 E-diene-18-oic acid, along with eight known diterpenes. Their structures were elucidated using spectroscopic methods as well as by comparison with previously reported data. The isolates showed antibacterial (Propionibacterium acnes) and antifungal activities.

Overview of acne and its treatment

Acne affects more than 85% of teenagers in the United States and often continues into adulthood. The most deleterious form can result in permanent scarring on the face, chest, and back. Although the pathogenic features of acne are well known, the initiating factor remains unknown. Isotretinoin is effective against all of the pathogenic features of acne but is contraindicated in pregnant women and has been associated with elevations in triglyceride levels. Combination regimens appear to be effective, but physicians should avoid prescribing complicated treatment regimens. Hormone therapy has been found to improve acne in some women and should be considered in appropriate candidates. Although the list of available and effective agents appears to be extensive, several are contraindicated in pregnant women, and long-term use of antibiotics to target inflammation has been linked to agranulocytosis and Stevens-Johnson syndrome. Further investigation into agents that can reduce sebum production is warranted.

Chemical composition and biological activities of essential oils extracted from Korean endemic citrus species

The aim of this study was to analyze the chemical composition of 14 kinds of citrus oils and to test their biological activities. Citrus essential oils were obtained by steam distillation from immature fruits collected from Jeju Island and were analyzed using gas chromatograph (GC)- flame ionization detectors (FID) and GC-MS. Limonene (55.4% to 91.7%), myrcene (2.1% to 32.1%), alpha-pinene (0.6% to 1.6%) and linalool (0.4% to 6.9%) were the major components in most citrus species. To evaluate in vitro antibacterial activity, all essential oils were tested against Propionibacterium acnes and Staphylococcus epidermidis. Nine out of fourteen citrus oils exhibited antibacterial activity against P. acnes, but not against S. epidermidis. The effects of the citrus oils on DPPH radical scavenging, superoxide radical anion scavenging, nitric oxide radical, and cytotoxicity were also assessed. Three essential citrus oils, Joadeung, Dongjunggyul, and Bujiwha, exhibited potent inhibitory effects on nitric oxide production. Two essential oils, Dongjunggyul and Joadeung, showed potent free radical scavenging activities in the DPPH assay. For future applications in cosmetic products, we also performed MTT assays in a human dermal fibroblast cell line. The majority of the essential oils showed no cytotoxicity. The results indicate that citrus essential oils can be useful natural agents for cosmetic application.

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.

Investigation of antibacterial activity of rosemary essential oil against Propionibacterium acnes with atomic force microscopy

In the present study, the antibacterial activity of rosemary (Rosmarinus officinalis L. Labiatae) essential oil against Propionibacterium acnes (P. acnes) was observed with atomic force microscopy (AFM). The MIC (minimal inhibitory concentration) value of rosemary essential oil against P.acnes was 0.56 mg/mL. Significant changes in morphology and size of P. acnes were observed by atomic force microscopy (AFM) in response to essential oil treatment. The essential oil first attached to the surface of P. acnes at low concentration, the width and height of the bacterial body became larger, whereas the length did not change considerably. With increasing concentration of the essential oil, the bacterial bodies were severely damaged. The length, width and height were all reduced, when the concentration was increased up to 64xMIC, the length, width and height were reduced by 42.56%, 92.00% and 41.58%, respectively. Furthermore, treated bacteria lost their native shape, the cell wall desquamated, and the cytoplasm leaked out of the bacterial body, finally leading to bacterial death. With the increasing time at MIC, the bacteria length was reduced at 8 h, the width and height gradually became smaller, the shape of the cell became distorted, and finally led to cell wall damage and bacterial death at 8 h. In conclusion, the AFM investigation of morphology and size of P. ACNES treated with rosemary essential oil represents a powerful technique, which can generally be applied to reveal the biological changing mechanisms of bacteria induced by antibacterial agents at the nanometer level.

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.

Community-based trial results of combination clindamycin 1%--benzoyl peroxide 5% topical gel plus tretinoin microsphere gel 0.04% or 0.1% or adapalene gel 0.1% in the treatment of moderate to severe acne

Acne is characterized by different types of lesions at different stages of development. Therefore, combination therapy may offer numerous advantages, including enhanced efficacy and better tolerability. The addition of benzoyl peroxide (BPO) to all long-term antibiotic treatment is widely advocated to help suppress the emergence of antibiotic-resistant bacteria. Topical retinoids are recommended as early initiation treatment of most patients with acne because they target most mechanisms of acne pathogenesis. In the clinical setting, therapeutic regimens that include retinoids and topical antibiotic-BPO combination formulations frequently are prescribed. This study investigated the efficacy and safety of combination therapy with clindamycin 1%-BPO 5% topical gel plus tretinoin microsphere (RAM) gel 0.04% or 0.1% or adapalene (AP) gel 0.1% in moderate to severe acne.

The impact and importance of resistance

Bacterial resistance to antibiotics began to emerge soon after their introduction. Beginning in the 1970s, Propionibacterium acnes also began to show decreased sensitivity to the antibiotics typically used in acne management. Clinically, this trend has translated to decreased efficacy and even nonresponse to therapy. A variety of recommendations regarding optimum use of antibiotics in acne management have been developed to preserve the utility of these drugs. Most important is the use of combination therapy with benzoyl peroxide (BPO) to help minimize the development of resistance. Retinoids also are recommended in acne therapeutic regimens because these agents are active against most acne pathogenetic mechanisms, but they have no apparent activity preventing antibiotic resistance when used in combination with a topical antibiotic.

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.