Antibiotics in acne: time for a rethink

Topical methylene blue nanoformulation for the photodynamic therapy of acne vulgaris

Acne vulgaris is a common skin disease caused by multifactorial reasons involving excessive sebum secretion and inflammation by Cutibacterium acnes (C. acnes). Various conventional therapies are available for the treatment of acne vulgaris; however, topical photodynamic therapy (PDT) has attracted much attention because of its great potential for sebum-reducing, anti-inflammatory, and antimicrobial activities. Although 5-aminolevulinic acid (ALA) has been broadly used as a photosensitizer for topical PDT, it has several limitations such as long incubation time, pain, and post-inflammatory hyperpigmentation. Here, we report a biocompatible nanoformulation consisting of methylene blue and salicylic acid (MBSD), as a potent PDT and acne therapeutics, enclosed within oleic acid. Photoactivated MBSD showed antimicrobial activity against C. acnes along with long-term stability. When 24 patients with acne were treated with MBSD and light irradiation 5 times at 1-week intervals, MBSD-based PDT exhibited a remarkable reduction in acne lesions and sebum production. In addition, the therapeutic procedure was painless and safe, without any adverse events. Therefore, MBSD is a promising topical PDT agent for biocompatible, safe, and effective acne treatment.

Pulsed 450 nm blue light suppresses MRSA and Propionibacterium acnes in planktonic cultures and bacterial biofilms

In our recent study, we showed that pulsed blue light (PBL) suppresses the growth of Propionibacterium acnes more than continuous wave (CW) blue light in vitro, but it is not known that other bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), respond similarly to PBL. The high potency of PBL relative to CW blue light makes it a suitable antimicrobial for suppressing bacterial growth in biofilms as well. Therefore, we determined if MRSA-a deadly bacterium of global concern-is susceptible to 450 nm PBL irradiation in vitro, and ascertained whether the bactericidal effect of PBL on planktonic P. acnes culture can be replicated in biofilms of P. acnes and MRSA. In three series of experiments, we irradiated P. acnes and MRSA respectively, either in planktonic cultures, forming biofilms or formed biofilms. Compared to controls, the results showed 100% bacterial suppression in planktonic cultures of MRSA irradiated with 3 mW/cm² irradiance and 7.6 J/cm² radiant exposure three times at 30-minute intervals, and also in P. acnes cultures irradiated with 2 mW/cm² irradiance 5 J/cm² radiant exposure thrice daily during each of 3 days. Irradiation of biofilms with the same irradiances and radiant exposures that gave 100% bacterial suppression in planktonic cultures resulted in disruption and disassembly of the architecture of MRSA and P. acnes biofilms, more so in forming biofilms than formed biofilms. The antimicrobial effect on each bacterium was minimal in forming biofilms, and even less in formed biofilms. Increasing radiant exposure slightly from 7.6 J/cm² to 10.8 J/cm² without changing any other parameter, yielded more disruption of the biofilm and fewer live MRSA and P. acnes, suggesting that 100% bacterial suppression is possible with further refinement of the protocol. In both planktonic cultures and biofilms, PBL suppressed MRSA more than P. acnes.

Non-antibiotic Isotretinoin Treatment Differentially Controls Propionibacterium acnes on Skin of Acne Patients

Emergence and potential transfer of antibiotic resistance in skin microorganisms is of current concern in medicine especially in dermatology contexts where long term treatment with antibiotics is common. Remarkably, non-antibiotic therapy in the form of isotretinoin – a non-antimicrobial retinoid is effective at reducing or eradicating the anaerobe Propionibacterium acnes which is causally involved in the complex pathogenesis of Acne vulgaris. This study measured the extent of colonization of P. acnes in patients with primary cystic or severe acne from three defined skin sites in ‘non-lesion’ areas before, during and after treatment with isotretinoin. Patients attending acne clinics were investigated using standardized skin sampling techniques and the recovery of anaerobic P. acnes from 56 patients comprising 24 females and 32 males (mean age 22 years, age range 15–46 years) who were given a standard course of isotretinoin (1 mg/kg/day) are reported. P. acnes cultured from the external cheek surface of patients following treatment showed a significant reduction (1–2 orders of magnitude) compared with their pre-treatment status. Interestingly, other distinct sites (nares and toe web) failed to show this reduction. In addition, high levels of antibiotic-resistant P. acnes were recorded in each patients’ skin microbiota before, during and after treatment. In this study, microbial composition of the skin appears substantially altered by isotretinoin treatment, which clearly has differential antimicrobial effects on each anatomically distinct site. Our study confirmed that orally administered isotretinoin shows good efficacy in the resolution of moderate to severe acne that correlates with reductions in the number of P. acnes on the skin, including resistant isolates potentially acquired from previous treatments with antibiotics. Our study suggests that the role of tetracycline’s and macrolides, which are currently first line treatments in dermatology, might be reserved for severe or life-threatening infections since current antibiotic stewardship guidelines from medical departments no longer prescribe these antibiotics for routine use.

The effect of photodynamic therapy using indole-3-acetic Acid and green light on acne vulgaris

Background

Photodynamic therapy (PDT) using topical aminolevulinic acid (ALA) has increasingly been used for the treatment of acne vulgaris and several studies have shown its clinical efficacy. However, ALA-PDT needs a relatively long incubation period and is frequently associated with adverse effects. Indole-3-acetic acid (IAA) has been introduced as a new photosensitizer for the treatment of acne in recent study. IAA-PDT requires only a short incubation period and the procedure is relatively painless in contrast to ALA-PDT.

Objective

To investigate the efficacy and safety of IAA- PDT in the treatment of acne.

Methods

Twenty-five patients with facial acne lesions were enrolled in this study. IAA-PDT was performed for five sessions at 1-week intervals (week 0~4). IAA was treated with 15 minute occlusion, and green light was given for 15 minutes. Clinical efficacy was determined by evaluating acne lesion counts, severity grading, and the Dermatology Life Quality Index (DLQI) at week 0, 2, 4, and 5. Sebum secretion and erythema index was measured by Sebumeter and Mexameter, respectively, at baseline and one week after each treatment session (week 1~5). Histopathological examination was performed at baseline and week 5. Adverse effects were recorded throughout the study.

Results

All the patients completed the study. Numbers of both inflammatory and non-inflammatory acne lesions were significantly decreased. Acne severity grade and the DLQI showed significant reduction. Sebum secretion and erythema were also reduced. Histopathological examination showed a reduction in inflammatory reactions. No adverse effects were observed except for transient pruritus in one patient.

Conclusion

PDT using IAA and green light was an effective, simple and safe treatment for acne.

About local administration of antibacterial drugs for acne therapy

The review summarizes and systematizes data accumulated in the world research literature, which are related to the role of P. acnes in the pathogenesis of acne, its microbiology and antibacterial resistance; it also examines antibacterial drugs for the external therapy of acne and recommendations for their use.

Optimizing use of oral antibiotics in acne vulgaris

Oral antibiotics are commonly used to treat acne vulgaris, primarily in patients presenting with moderate to severe facial or truncal disease severity. These agents are most appropriately used in combination with a topical regimen containing benzoyl peroxide and a topical retinoid. The most common oral antibiotics for treating acne vulgaris are the tetracycline derivatives, although macrolide agents such as erythromycin have also been used extensively. Over the past 4 decades, as the sensitivity of Propionibacterium acnes to several oral and topical antibiotics has decreased, the efficacy of oral tetracycline and erythromycin has markedly diminished, leading to increased use of doxycycline, minocycline, and other agents, such as trimethoprim/sulfamethoxazole.

Acne: more than skin deep

Acne is one of the most prevalent skin conditions affecting teenagers. It is a disease of the pilosebaceous unit. Blockage of sebaceous glands and colonisation with Proionobacterium acnes leads to acne. Grading the severity of acne helps to determine the appropriate treatment. Treatment of acne should be started as early as possible to minimise the risk of scarring and adverse psychological effects. It should be tailored to the individual patient, the type of acne, its severity, the patient's ability to use the treatment, and the psychological state. Topical agents are the mainstay for treatment of mild acne. Moderate acne is treated with oral antibiotics. Resistance to antibiotics may be reduced by subsequent use of non-antibiotic topical medications. Severe acne is treated with isotretinoin, and this can lead to permanent remission. With better education and care given by medical profession, acne treatment could be significantly improved.

Acne vulgaris: a review of antibiotic therapy

Antibiotic therapy has been integral to the management of inflammatory acne vulgaris for many years. Systemic antibiotics work via antibacterial, anti-inflammatory and immunomodulatory modes of action, and have been found to be useful in managing moderate-to-severe acne. Commonly prescribed antibiotics include tetracyclines, erythromycin and trimethoprim, with or without sulfamethoxazole. In selecting the appropriate antibiotic for patients needing to receive topical or systemic antibiotic therapy, the clinician should take into account the severity of the acne, cost-effectiveness, the safety profile of the drug and the potential for development of resistance. The widespread and long-term use of antibiotics over the years has unfortunately led to the emergence of resistant bacteria. The global increase in the antibiotic resistance of Propionibacterium acnes may be a significant contributing factor in treatment failures. It is therefore essential that clinicians prescribing antibiotics for the treatment of acne adopt strategies to minimise further development of bacterial resistance. This includes addressing compliance issues, using combination therapies, avoiding prolonged antibiotic treatment, and avoiding concomitant topical and oral antibiotics with chemically dissimilar antibiotics.

The new age of acne therapy: light, lasers, and radiofrequency

BACKGROUND

Current treatments for acne vulgaris include topical and oral medications that counteract microcomedone formation, sebum production, Propionibacterium acnes, and inflammation. Concerns about the short- and long-term consequences of these medications, along with technological advancements, have to significant progress in the management of acne. These developments include light, laser, and radio frequency, which may offer faster onset of action, equal or greater efficacy, and greater convenience than traditional approaches.

CONCLUSION

Research emphasizing long-term follow-up and comparative, randomized trials is necessary to determine whether these emerging technologies will become a viable alternative to standard therapies such as antibiotics.

Treatment of acne with topical antibiotics: lessons from clinical studies

BACKGROUND

Over the past 20 years, major concerns have been repeatedly expressed over antibiotic-resistant acne in Europe and in the U.S.A. However, the clinical significance of these resistance patterns is poorly defined so that topical antibiotics remain one of the cornerstones of acne management.

OBJECTIVES

To determine whether we are facing decreased efficacy of topical formulations of erythromycin and clindamycin in clinical trials of therapeutic interventions for acne.

METHODS

To review systematically the results of the clinical trials investigating topical formulations of erythromycin and clindamycin for the treatment of inflammatory acne and to establish whether or not there is a decrease in the efficacy of these topical antibiotic formulations since their widespread introduction in the mid 1970s.

RESULTS

Of the 50 eligible controlled trials identified using a systematic electronic database search strategy, 45 (90%) incorporated a lesion count, making comparison across trials possible. Analysis of clinical studies investigating the effect of topical erythromycin in acne patients indicates a significant decrease in the effect of this antibiotic on inflammatory and noninflammatory lesion count over time (r = -2.140, P = 0.001 and r = -2.032, P = 0.001, respectively). Efficacy of topical clindamycin remained stable during the study period.

CONCLUSIONS

There is a gradual decrease in the efficacy of topical erythromycin in clinical trials of therapeutic intervention for acne, which is probably related to the development of antibiotic-resistant propionibacteria.

The pustular skin lesions in Behcet's syndrome are not sterile

BACKGROUND

The pustular skin lesions of Behcet's syndrome (BS) are clinically and histopathologically similar to ordinary acne, but BS patients get lesions at sites not commonly involved in acne, such as the legs and arms. The microbiology of these lesions has not been studied adequately.

OBJECTIVE

To make a detailed study of the microbiology of BS lesions.

METHODS

Subjects were patients with BS and acne vulgaris. Material was extracted from pustular lesions and directly plated to aerobic and anaerobic media by sterile swab. Anaerobic bacteria were identified using a commercial kit (API 20A). Aerobic bacteria were defined by standard procedures.

RESULTS

58 BS patients and 37 acne patients were studied. Pustules were cultured from the following sites: BS patients (70 pustules): face (17), back (30), chest (2), arm (4), leg (17); acne patients (37 pustules): face (27), back (6), chest (1), arm (2), leg (1). At least one type of microorganism was grown from each pustule. Staphylococcus aureus (41/70, 58.6%, p = 0.008) and Prevotella spp (17/70, 24.3%, p = 0.002) were significantly more common in pustules from BS patients, and coagulase negative staphylococci (17/37, 45.9%, p = 0.007) in pustules from acne patients.

CONCLUSIONS

The pustular lesions of BS are not usually sterile. The microbiology of these lesions is different from ordinary acne. It remains to be determined whether the infection is secondary or has any pathogenic implications.

Eradication of Propionibacterium acnes by its endogenic porphyrins after illumination with high intensity blue light

Propionibacterium acnes is a Gram-positive, microaerophilic bacterium that causes skin wounds. It is known to naturally produce high amounts of intracellular porphyrins. The results of the present study confirm that the investigated strain of P. acnes is capable of producing endogenic porphyrins with no need for any trigger molecules. Extracts from growing cultures have demonstrated emission peaks around 612 nm when excited at 405 nm, which are characteristic for porphyrins. Endogenic porphyrins were determined and quantified after their extraction from the bacterial cells by fluorescence intensity and by elution retention time on high-performance liquid chromatography (HPLC). The porphyrins produced by P. acnes are mostly coproporphyrin, as shown by the HPLC elution patterns. Addition of delta-aminolevulinic acid (ALA) enhanced intracellular porphyrin synthesis and higher amounts of coproporphyrin have been found. Eradication of P. acnes by its endogenic porphyrins was examined after illumination with intense blue light at 407-420 nm. The viability of 24 h cultures grown anaerobically in liquid medium was reduced by less than two orders of magnitude when illuminated once with a light dose of 75 J cm(-2). Better photodynamic effects were obtained when cultures were illuminated twice or three times consecutively with a light dose of 75 J cm(-2) and an interval of 24 h between illuminations. The viability of the culture under these conditions decreased by four orders of magnitude after two illuminations and by five orders of magnitude after three illuminations. When ALA-triggered cultures were illuminated with intense blue light at a light dose of 75 J cm(-2) the viability of the treated cultures decreased by seven orders of magnitude. This decrease in viability can occur even after a single exposure of illumination for the indicated light intensity. X-ray microanalysis and transmission electron microscopy revealed structural damages to membranes in the illuminated P. acnes. Illumination of the endogenous coproporphyrin with blue light (407-420 nm) apparently plays a major role in P. acnes photoinactivation. A treatment protocol with a series of several illuminations or illumination after application of ALA may be suitable for curing acne. Treatment by both pathways may overcome the resistance of P. acnes to antibiotic treatment.