Inhibition of erythromycin-resistant propionibacteria on the skin of acne patients by topical erythromycin with and without zinc

Comparative Efficacy of Pharmacological and Nonpharmacological Interventions for Acne Vulgaris: A Network Meta-Analysis

Acne has several effects on physical symptoms, but the main impacts are on the quality of life, which can be improved by treatment. There are several acne treatments but less evidence comparing their relative efficacy. Thus, we assessed the comparative efficacy of pharmacological and nonpharmacological interventions for acne. We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception to April 2019, to include randomized controlled trials for acne that compared topical antibiotics (TA), benzoyl peroxide (BPO), topical retinoids (TR), oral antibiotics (OA), lasers, light devices including LED device (LED), photodynamic therapy (PDT), and intense pulsed light, chemical peels (CP), miscellaneous therapies or complementary and alternative medicine (MTCAM), or their combinations. We performed Bayesian network meta-analysis with random effects for all treatments compared with placebo and each other. Mean differences (MDs) of lesions count and risk ratios of adverse events with their 95% credible intervals (CrIs) were calculated, and all interventions were ranked by the Surface Under the Cumulative Ranking (SUCRA) values. Additional frequentist additive network meta-analysis was performed to detect the robustness of results and potential interaction effects. Sensitivity analyses were carried out with different priors, and metaregression was to adjust for nine potential effect modifiers. In the result, seventy-three randomized controlled trials (27,745 patients with mild to moderate acne), comparing 30 grouped intervention categories, were included with low to moderate risk of bias. For adverse effects, OA had more risk in combination treatment with others. For noninflammatory lesions reduction, seventeen interventions had significant differences comparing with placebo and three interventions (TR+BPO: MD = −21.89, 95%CrI [−28.97, −14.76]; TR+BPO+MTCAM: −22.48 [−34.13, −10.70]; TA+BPO+CP: −20.63 [−33.97, −7.13]) were superior to others with 94, 94, and 91% SUCRA values, respectively. For inflammatory lesions reduction, nineteen interventions were significantly better than placebo, and three interventions (TR+BPO: MD = −12.13, 95%CrI [−18.41, −5.80]; TR+BPO+MTCAM: −13.21 [−.39, −3.04]; LED: −11.30 [−18.34, −4.42]) were superior to others (SUCRA: 81, 81, and 77%, respectively). In summary of noninflammatory and inflammatory lesions results, TR+BPO and TA+BPO were the best options compared to others. The frequentist model showed similar results as above. In summary, current evidence supports the suggestion that TR+BPO and TA+BPO are the best options for mild to moderate acne. LED is another option for inflammatory lesions when drug resistance occurs. All the combinations involved with OA showed more risk of adverse events than others. However, the evidence of this study should be cautiously used due to the limitations.

Evidence-based topical treatments (azelaic acid, salicylic acid, nicotinamide, sulfur, zinc, and fruit acid) for acne: an abridged version of a Cochrane systematic review

OBJECTIVE

The effects of topical azelaic acid, salicylic acid, nicotinamide, sulfur, zinc, and fruit acid (alpha-hydroxy acid) for acne are unclear. We aimed to assess the effects of these topical treatments by collecting randomized controlled trials.

METHODS

We searched The Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS up to May 2019. We also searched five trials registers. Two review authors independently extracted data and assessed risk of bias. Meta analyses were performed by using Review Manager 5 software.

RESULTS

We included a total of 49 trials involving 3880 participants. In terms of treatment response (measured using participants' global self-assessment of acne improvement, PGA), azelaic acid was probably less effective than benzoyl peroxide (RR = 0.82, 95% CI 0.72-0.95). However, there was probably little or no difference in PGA when comparing azelaic acid to tretinoin (RR = 0.94, 95% CI 0.78-1.14). There may be little or no difference when comparing salicylic acid to tretinoin (RR = 1.00, 95% CI 0.92-1.09). There were no studies measured PGA when evaluating nicotinamide. With respect to alpha-hydroxy acid, there may be no difference in PGA when comparing glycolic acid to salicylic-mandelic acid (RR = 1.06, 95% CI 0.88-1.26). We were uncertain about the effects of sulfur and zinc. Adverse events associated with these topical treatments were always mild and transient.

CONCLUSIONS

Moderate-quality evidence was available for azelaic acid and low- to very-low-quality evidence for other topical treatments. Risk of bias and imprecision limit our confidence in the evidence.

Topical azelaic acid, salicylic acid, nicotinamide, sulphur, zinc and fruit acid (alpha-hydroxy acid) for acne

BACKGROUND

Acne is an inflammatory disorder with a high global burden. It is common in adolescents and primarily affects sebaceous gland-rich areas. The clinical benefit of the topical acne treatments azelaic acid, salicylic acid, nicotinamide, sulphur, zinc, and alpha-hydroxy acid is unclear.

OBJECTIVES

To assess the effects of topical treatments (azelaic acid, salicylic acid, nicotinamide, zinc, alpha-hydroxy acid, and sulphur) for acne.

SEARCH METHODS

We searched the following databases up to May 2019: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers.

SELECTION CRITERIA

Clinical randomised controlled trials of the six topical treatments compared with other topical treatments, placebo, or no treatment in people with acne.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Key outcomes included participants' global self-assessment of acne improvement (PGA), withdrawal for any reason, minor adverse events (assessed as total number of participants who experienced at least one minor adverse event), and quality of life.

MAIN RESULTS

We included 49 trials (3880 reported participants) set in clinics, hospitals, research centres, and university settings in Europe, Asia, and the USA. The vast majority of participants had mild to moderate acne, were aged between 12 to 30 years (range: 10 to 45 years), and were female. Treatment lasted over eight weeks in 59% of the studies. Study duration ranged from three months to three years. We assessed 26 studies as being at high risk of bias in at least one domain, but most domains were at low or unclear risk of bias. We grouped outcome assessment into short-term (less than or equal to 4 weeks), medium-term (from 5 to 8 weeks), and long-term treatment (more than 8 weeks). The following results were measured at the end of treatment, which was mainly long-term for the PGA outcome and mixed length (medium-term mainly) for minor adverse events. Azelaic acid In terms of treatment response (PGA), azelaic acid is probably less effective than benzoyl peroxide (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.72 to 0.95; 1 study, 351 participants), but there is probably little or no difference when comparing azelaic acid to tretinoin (RR 0.94, 95% CI 0.78 to 1.14; 1 study, 289 participants) (both moderate-quality evidence). There may be little or no difference in PGA when comparing azelaic acid to clindamycin (RR 1.13, 95% CI 0.92 to 1.38; 1 study, 229 participants; low-quality evidence), but we are uncertain whether there is a difference between azelaic acid and adapalene (1 study, 55 participants; very low-quality evidence). Low-quality evidence indicates there may be no differences in rates of withdrawal for any reason when comparing azelaic acid with benzoyl peroxide (RR 0.88, 95% CI 0.60 to 1.29; 1 study, 351 participants), clindamycin (RR 1.30, 95% CI 0.48 to 3.56; 2 studies, 329 participants), or tretinoin (RR 0.66, 95% CI 0.29 to 1.47; 2 studies, 309 participants), but we are uncertain whether there is a difference between azelaic acid and adapalene (1 study, 55 participants; very low-quality evidence). In terms of total minor adverse events, we are uncertain if there is a difference between azelaic acid compared to adapalene (1 study; 55 participants) or benzoyl peroxide (1 study, 30 participants) (both very low-quality evidence). There may be no difference when comparing azelaic acid to clindamycin (RR 1.50, 95% CI 0.67 to 3.35; 1 study, 100 participants; low-quality evidence). Total minor adverse events were not reported in the comparison of azelaic acid versus tretinoin, but individual application site reactions were reported, such as scaling. Salicylic acid For PGA, there may be little or no difference between salicylic acid and tretinoin (RR 1.00, 95% CI 0.92 to 1.09; 1 study, 46 participants; low-quality evidence); we are not certain whether there is a difference between salicylic acid and pyruvic acid (1 study, 86 participants; very low-quality evidence); and PGA was not measured in the comparison of salicylic acid versus benzoyl peroxide. There may be no difference between groups in withdrawals when comparing salicylic acid and pyruvic acid (RR 0.89, 95% CI 0.53 to 1.50; 1 study, 86 participants); when salicylic acid was compared to tretinoin, neither group had withdrawals (both based on low-quality evidence (2 studies, 74 participants)). We are uncertain whether there is a difference in withdrawals between salicylic acid and benzoyl peroxide (1 study, 41 participants; very low-quality evidence). For total minor adverse events, we are uncertain if there is any difference between salicylic acid and benzoyl peroxide (1 study, 41 participants) or tretinoin (2 studies, 74 participants) (both very low-quality evidence). This outcome was not reported for salicylic acid versus pyruvic acid, but individual application site reactions were reported, such as scaling and redness. Nicotinamide Four studies evaluated nicotinamide against clindamycin or erythromycin, but none measured PGA. Low-quality evidence showed there may be no difference in withdrawals between nicotinamide and clindamycin (RR 1.12, 95% CI 0.49 to 2.60; 3 studies, 216 participants) or erythromycin (RR 1.40, 95% CI 0.46 to 4.22; 1 study, 158 participants), or in total minor adverse events between nicotinamide and clindamycin (RR 1.20, 95% CI 0.73 to 1.99; 3 studies, 216 participants; low-quality evidence). Total minor adverse events were not reported in the nicotinamide versus erythromycin comparison. Alpha-hydroxy (fruit) acid There may be no difference in PGA when comparing glycolic acid peel to salicylic-mandelic acid peel (RR 1.06, 95% CI 0.88 to 1.26; 1 study, 40 participants; low-quality evidence), and we are uncertain if there is a difference in total minor adverse events due to very low-quality evidence (1 study, 44 participants). Neither group had withdrawals (2 studies, 84 participants; low-quality evidence).

AUTHORS' CONCLUSIONS

Compared to benzoyl peroxide, azelaic acid probably leads to a worse treatment response, measured using PGA. When compared to tretinoin, azelaic acid probably makes little or no difference to treatment response. For other comparisons and outcomes the quality of evidence was low or very low. Risk of bias and imprecision limit our confidence in the evidence. We encourage the comparison of more methodologically robust head-to-head trials against commonly used active drugs.

Efficacy and Safety of VB-1953 Topical Gel in Non-Responder Acne Patients with Clindamycin-Resistant Cutibacterium acnes

BACKGROUND AND OBJECTIVES

The emergence of resistant strains of Cutibacterium acnes can limit the efficacy of currently approved antibiotics for acne. VB-1953 is a next-generation antibiotic that exerts a bactericidal effect on resistant C. acnes. In this study, we investigated the safety, tolerability, and efficacy of VB-1953 topical gel in patients with moderate to severe acne having clindamycin-resistant C. acnes.

METHODS

An investigator-initiated, open label, single-arm clinical study was conducted in patients with moderate to severe facial acne vulgaris showing poor or no response to previous clindamycin treatment. Nineteen subjects were enrolled in the study based on laboratory screening for the presence of clindamycin-resistant C. acnes in acne swab samples collected from patients. VB-1953 2% gel was applied on the entire face twice daily over 12 weeks. The primary efficacy endpoints were absolute changes in inflammatory and noninflammatory lesion counts from baseline at week 12, while the secondary efficacy endpoint was the proportion of subjects achieving Investigator Global Assessment success (score of 0 or 1) or a grade 2 or higher improvement from baseline at week 12. The presence and severity of local skin reactions (erythema, edema, scaling/dryness, burning/stinging, pruritus) were evaluated for safety. Additionally, the detection and quantification of drug-resistant C. acnes strains were performed in the laboratory using acne swab samples collected from patients.

RESULTS

The occurrence of treatment-emergent adverse events or changes in vital signs, physical examinations, and urinalysis for any of the patients during the course of the entire study were clinically insignificant. Topical application of 2% VB-1953 topical gel resulted in a significant reduction of mean absolute inflammatory and noninflammatory lesion counts by 53.1% and 52.2%, respectively (p < 0.0001 for both), with an Investigator Global Assessment success of 26.3% at week 12 compared with baseline. Resistant bacteria were reduced by (94.3 ± 1%; p < 0.05) within 12 weeks of treatment with VB-1953.

CONCLUSION

These results indicate that VB-1953 topical gel can be a safe and effective therapy for moderate to severe acne with underlying resistant C. acnes in subjects who had not responded to previous antibiotic treatments.

Topical benzoyl peroxide for acne

BACKGROUND

Acne is a common, economically burdensome condition that can cause psychological harm and, potentially, scarring. Topical benzoyl peroxide (BPO) is a widely used acne treatment; however, its efficacy and safety have not been clearly evaluated.

OBJECTIVES

To assess the effects of BPO for acne.

SEARCH METHODS

We searched the following databases up to February 2019: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of relevant randomised controlled trials (RCTs) and systematic reviews.

SELECTION CRITERIA

We included RCTs that compared topical BPO used alone (including different formulations and concentrations of BPO) or as part of combination treatment against placebo, no treatment, or other active topical medications for clinically diagnosed acne (used alone or in combination with other topical drugs not containing BPO) on the face or trunk.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane. Primary outcome measures were 'participant global self-assessment of acne improvement' and 'withdrawal due to adverse events in the whole course of a trial'. 'Percentage of participants experiencing any adverse event in the whole course of a trial' was a key secondary outcome.

MAIN RESULTS

We included 120 trials (29,592 participants randomised in 116 trials; in four trials the number of randomised participants was unclear). Ninety-one studies included males and females. When reported, 72 trials included participants with mild to moderate acne, 26 included participants with severe acne, and the mean age of participants ranged from 18 to 30 years. Our included trials assessed BPO as monotherapy, as add-on treatment, or combined with other active treatments, as well as BPO of different concentrations and BPO delivered through different vehicles. Comparators included different concentrations or formulations of BPO, placebo, no treatment, or other active treatments given alone or combined. Treatment duration in 80 trials was longer than eight weeks and was only up to 12 weeks in 108 trials. Industry funded 50 trials; 63 trials did not report funding. We commonly found high or unclear risk of performance, detection, or attrition bias. Trial setting was under-reported but included hospitals, medical centres/departments, clinics, general practices, and student health centres. We reported on outcomes assessed at the end of treatment, and we classified treatment periods as short-term (two to four weeks), medium-term (five to eight weeks), or long-term (longer than eight weeks). For 'participant-reported acne improvement', BPO may be more effective than placebo or no treatment (risk ratio (RR) 1.27, 95% confidence interval (CI) 1.12 to 1.45; 3 RCTs; 2234 participants; treatment for 10 to 12 weeks; low-certainty evidence). Based on low-certainty evidence, there may be little to no difference between BPO and adapalene (RR 0.99, 95% CI 0.90 to 1.10; 5 RCTs; 1472 participants; treatment for 11 to 12 weeks) or between BPO and clindamycin (RR 0.95, 95% CI 0.68 to 1.34; 1 RCT; 240 participants; treatment for 10 weeks) (outcome not reported for BPO versus erythromycin or salicylic acid). For 'withdrawal due to adverse effects', risk of treatment discontinuation may be higher with BPO compared with placebo or no treatment (RR 2.13, 95% CI 1.55 to 2.93; 24 RCTs; 13,744 participants; treatment for 10 to 12 weeks; low-certainty evidence); the most common causes of withdrawal were erythema, pruritus, and skin burning. Only very low-certainty evidence was available for the following comparisons: BPO versus adapalene (RR 1.85, 95% CI 0.94 to 3.64; 11 RCTs; 3295 participants; treatment for 11 to 24 weeks; causes of withdrawal not clear), BPO versus clindamycin (RR 1.93, 95% CI 0.90 to 4.11; 8 RCTs; 3330 participants; treatment for 10 to 12 weeks; causes of withdrawal included local hypersensitivity, pruritus, erythema, face oedema, rash, and skin burning), erythromycin (RR 1.00, 95% CI 0.07 to 15.26; 1 RCT; 60 participants; treatment for 8 weeks; withdrawal due to dermatitis), and salicylic acid (no participants had adverse event-related withdrawal; 1 RCT; 59 participants; treatment for 12 weeks). There may be little to no difference between these groups in terms of withdrawal; however, we are unsure of the results because the evidence is of very low certainty. For 'proportion of participants experiencing any adverse event', very low-certainty evidence leaves us uncertain about whether BPO increased adverse events when compared with placebo or no treatment (RR 1.40, 95% CI 1.15 to 1.70; 21 RCTs; 11,028 participants; treatment for 10 to 12 weeks), with adapalene (RR 0.71, 95% CI 0.50 to 1.00; 7 RCTs; 2120 participants; treatment for 11 to 24 weeks), with erythromycin (no participants reported any adverse events; 1 RCT; 89 participants; treatment for 10 weeks), or with salicylic acid (RR 4.77, 95% CI 0.24 to 93.67; 1 RCT; 41 participants; treatment for 6 weeks). Moderate-certainty evidence shows that the risk of adverse events may be increased for BPO versus clindamycin (RR 1.24, 95% CI 0.97 to 1.58; 6 RCTs; 3018 participants; treatment for 10 to 12 weeks); however, the 95% CI indicates that BPO might make little to no difference. Most reported adverse events were mild to moderate, and local dryness, irritation, dermatitis, erythema, application site pain, and pruritus were the most common.

AUTHORS' CONCLUSIONS

Current evidence suggests that BPO as monotherapy or add-on treatment may be more effective than placebo or no treatment for improving acne, and there may be little to no difference between BPO and either adapalene or clindamycin. Our key efficacy evidence is based on participant self-assessment; trials of BPO versus erythromycin or salicylic acid did not report this outcome. For adverse effects, the evidence is very uncertain regarding BPO compared with adapalene, erythromycin, or salicylic acid. However, risk of treatment discontinuation may be higher with BPO compared with placebo or no treatment. Withdrawal may be linked to tolerability rather than to safety. Risk of mild to moderate adverse events may be higher with BPO compared with clindamycin. Further trials should assess the comparative effects of different preparations or concentrations of BPO and combination BPO versus monotherapy. These trials should fully assess and report adverse effects and patient-reported outcomes measured on a standardised scale.

Clinical assessment of topical erythromycin gel with and without zinc acetate for treating mild-to-moderate acne vulgaris

Purpose: Erythromycin is an effective topical antibiotic for treating mild-to-moderate inflammatory acne vulgaris, especially papules acne during puberty as well as papules - pustular acne in adult women. Erythromycin is a macrolide antibiotic that has long been used as a topical dosage form to treat acne. It has favorable effects in resolving inflammatory acne lesions not only by reducing Propioni bacterium acnes density, but also by directly inhibiting neutrophil chemotactic factors and reactive oxygen species (ROS) production. Zinc, a metallic element has bacteriostatic activity against Propioni bacterium acnes. Combining zinc with antibiotic (erythromycin) can reduce antibiotic resistance and increase antibiotic absorption in-to the skin.Material and methods: In the present study, erythromycin (2% w/v) with zinc acetate (1.2% w/v) as 'topical gel' and erythromycin (2% w/v) gel alone were evaluated for treating mild to moderate inflammatory acne vulgaris. This double-blind study was carried out on 102 patients 13-25 years of age, divided into two groups. The group A received erythromycin and group B received erythromycin with zinc acetate topical gels during 3 weeks. Acne grading and lesion counts for comedones, papules and pustules were performed during each visit zero, first, second and third weeks.Results: Erythromycin treatment (with zinc acetate) gel showed to be more effective than erythromycin (alone) gel with respect to reducing the number of acne lesions and severity grade of acne.Number of lesions and severity of acne were significantly reduced at the end of 3rd week in both groups (p < .001). Conclusions: In conclusion, it can be stated that erythromycin with and without zinc acetate was clinically effective, and both formulations produced a significant reductions in acne grading as well as inflamed and noninflamed lesion counts (p < .000). Statistically, there was no significant difference between formulation A and B.

A review of diagnosis and treatment of acne in adult female patients

This review focuses on the treatment options for adult female patients with acne. Acne in adult female patients may start during adolescence and persist or have an onset in adulthood. Acne has various psychosocial effects that impact patients’ quality of life. Treatment of acne in adult women specifically has its challenges due to the considerations of patient preferences, pregnancy, and lactation. Treatments vary widely and treatment should be tailored specifically for each individual woman. We review conventional therapies with high levels of evidence, additional treatments with support from cohort studies and case reports, complementary and/or alternative therapies, and new agents under development for the treatment of patients with acne.

The role of zinc in the treatment of acne: A review of the literature

Acne vulgaris is a chronic disease of the pilosebaceous units presenting as inflammatory or noninflammatory lesions in individuals of all ages. The current standard of treatment includes topical formulations in the forms of washes, gels, lotions, and creams such as antibiotics, antibacterial agents, retinoids, and comedolytics. Additionally, systemic treatments are available for more severe or resistant forms of acne. Nevertheless, these treatments have shown to induce a wide array of adverse effects, including dryness, peeling, erythema, and even fetal defects and embolic events. Zinc is a promising alternative to other acne treatments owing to its low cost, efficacy, and lack of systemic side effects. In this literature review, we evaluate the effectiveness and side-effect profiles of various formulations of zinc used to treat acne.

Guidelines of care for the management of acne vulgaris

Acne is one of the most common disorders treated by dermatologists and other health care providers. While it most often affects adolescents, it is not uncommon in adults and can also be seen in children. This evidence-based guideline addresses important clinical questions that arise in its management. Issues from grading of acne to the topical and systemic management of the disease are reviewed. Suggestions on use are provided based on available evidence.

Topical acne treatments in Europe and the issue of antimicrobial resistance

Acne vulgaris (acne) is a chronic inflammatory disease of the sebaceous gland, characterized by follicular hyperkeratinization, excessive colonization by Propionibacterium acnes (P. acnes) as well as immune reactions and inflammation. Despite an armamentarium of topical treatments available including benzoyl peroxide, retinoids and azelaic acid, topical antibiotics in monotherapies, especially erythromycin and clindamycin, are still used in Europe to treat acne. This intensive use led to antimicrobial-resistant P. acnes and staphylococci strains becoming one of the main health issues worldwide. This is an update on the current topical acne treatments available in Europe, their mechanism of action, their potential to induce antimicrobial resistance and their clinical efficacy and safety.

Zineryt: external therapy of acne

Acne is a socially significant disease affecting an overwhelming majority of teenagers, which often results in serious social disadaptation. The problem of acne treatment remains urgent especially taking into consideration the fact that the respective pathogen, P. acnes, demonstrates a growth in its resistance. The problem can be solved by using a combination therapy comprising resistance inhibiting drugs along with antibiotics. The erythromycin and zinc solution is one of the most promising combinations.

Zinc, its biological role and use in dermatology

This literature review detines the biological role ot zinc in the human body, immune homeostasis and skin physiology as well as pathophysiology ot skin diseases. It describes the current range ot systemic and topical zinc preparations and their pharmacological characteristics. The review also describes skin diseases that may be treated with the use ot zinc preparations on a grounded basis, and discloses the clinical experience ot the use ot these drugs described in the world literature. It sets out certain recommendations tor using zinc preparations in clinical practice.

The skin microbiome: current perspectives and future challenges

Complex communities of bacteria, fungi, and viruses thrive on our skin. The composition of these communities depends on skin characteristics, such as sebaceous gland concentration, moisture content, and temperature, as well as on host genetics and exogenous environmental factors. Recent metagenomic studies have uncovered a surprising diversity within these ecosystems and have fostered a new view of commensal organisms as playing a much larger role in immune modulation and epithelial health than previously expected. Understanding microbe-host interactions and discovering the factors that drive microbial colonization will help us understand the pathogenesis of skin diseases and develop new promicrobial and antimicrobial therapeutics.

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.

Topical antimicrobial treatment of acne vulgaris: an evidence-based review

Topical antimicrobial treatment is indicated for mild to moderate acne vulgaris. Our literature review includes searches of Ovid, MEDLINE, EMBASE, and the databases of the Cochrane Library. A detailed search strategy is included. All searches were limited to controlled trials and systematic reviews. No year limits were applied to the searches, but we focused on trials, guidelines, and reviews published since 2004, the year that the last review of topical antimicrobials was published in this journal. Several controlled trials demonstrate that benzoyl peroxide, topical antibiotics, and topical retinoids used in combination provide the greatest efficacy and safety profile for the treatment of mild to moderate acne, but there are few trials directly comparing different combinations of these topical therapies with one another. Additionally, robust studies comparing cost and efficacy of generic combinations of the above agents with proprietary fixed-dose combination therapies that may increase compliance are also lacking. Although they have not been extensively studied, alternative agents including dapsone, salicylic acid, azelaic acid, and zinc are safe and efficacious when combined with traditional therapies.

Treating acne with antibiotic-resistant bacterial colonization

INTRODUCTION

Acne is a chronic skin disorder of the pilosebaceous unit; it has a multifactorial pathogenesis. Propionibacterium acnes within the follicle is considered to be a triggering factor of inflammation in acne. Antibiotics have been the primary treatment against P. acnes for more than 40 years. However, a gradual increase in the prevalence of antibiotic-resistant strains of P. acnes has been observed.

AREAS COVERED

This review discusses the pathophysiology of antibiotic-resistant acne development. It focuses on strategies to minimize the development of resistance and, most importantly, confront the development of antibiotic-resistant acne. The literature search was conducted up to August 2010, using the search terms 'acne', 'antibiotic-resistant acne' and 'bacterial resistance'.

EXPERT OPINION

Antibiotic-resistant acne is a real phenomenon. Strategies to prevent and confront it should include not only the use of certain treatment regimens but also rational prescribing policies, combination therapies, use of antibacterial non-antibiotic agents and treatment options targeting all the pathogenetic components of acne. Benzoyl-peroxide-based treatment is the most evidence-based approach. Oral isotretinoin remains the most efficacious option for severe acne.

Acne vulgaris treatment : the current scenario

Acne Vulgaris is one of the most common skin disorders which dermatologists have to treat. It mainly affect adolescent, though may present at any age. In recent years, due to better understanding of the pathogenesis of acne, new therapeutic modalities and various permutation and combinations have been designed. In topical agents; benzoyl peroxide, antibiotics, retinoids, etc are the mainstay of treatment; can be given in combinations. While systemic therapy includes oral antibiotics, hormonal therapy, and isotretinoin, depending upon the need of patients it has to be selected. Physical treatment in the form of lesion removal, photo-therapy is also helpful in few of them. Since various old and new topical and systemic agents are available to treat acne, it sometime confuse treating dermatologist. To overcome this, panel of physicians and researchers worked together as a global alliance and task force to improve outcomes in acne treatment. They have tried to give consensus recommendation for the treatment of acne. Successful management of acne needs careful selection of anti-acne agents according to clinical presentation and individual patient needs.

Innovative uses for zinc in dermatology

Severe zinc deficiency states, such as acrodermatitis enteropathica, are associated with a variety of skin manifestations, such as perioral, acral, and perineal dermatitis. These syndromes can be reversed with systemic zinc repletion. In addition to skin pathologies that are clearly zinc-dependent, many dermatologic conditions (eg, dandruff, acne, and diaper rash) have been associated and treated with zinc. Success rates for treatment with zinc vary greatly depending on the disease, mode of administration, and precise zinc preparation used. With the exception of systemic zinc deficiency states, there is little evidence that convincingly demonstrates the efficacy of zinc as a reliable first-line treatment for most dermatologic conditions. However, zinc may be considered as an adjunctive treatment modality. Further research is needed to establish the indications for zinc treatment in dermatology, optimal mode of zinc delivery, and best type of zinc compound to be used.

A randomized, single-blind comparison of topical clindamycin + benzoyl peroxide (Duac) and erythromycin + zinc acetate (Zineryt) in the treatment of mild to moderate facial acne vulgaris

BACKGROUND

Antibiotics are often combined with other agents to provide topical acne treatments that are effective against both inflammatory and non-inflammatory lesions and minimize the development of antibiotic resistance.

OBJECTIVES

To compare the clinical effectiveness of two combination treatments for facial acne: a ready mixed, once daily gel containing clindamycin phosphate (1%) plus benzoyl peroxide (5%) (CDP + BPO) and a twice daily solution of erythromycin (4%) plus zinc acetate (1.2%) (ERY + Zn).

METHODS/PATIENTS

In this assessor-blind, randomized study, 73 patients were treated with CDP + BPO once daily and 75 patients with ERY + Zn twice daily. The treatment period was 12 weeks and lesion counts and global improvement were assessed at weeks 1, 2, 4, 8 and 12.

RESULTS

CDP + BPO showed an earlier onset of action with a faster significant reduction in total lesion counts than ERY + Zn. The proportion of patients with at least a 30% improvement in non-inflammatory lesions at week 1 was 31.5% for CDP + BPO and 17.3% for ERY + Zn; the corresponding percentages for inflammatory lesions were 39.7% and 29.3%. A difference was also observed at week 2 (53.4% vs. 36.0% for non-inflammatory lesions and 72.6% vs. 53.3% for inflammatory lesions). The trend in favour of CDP + BPO, although less marked, continued to the end of the study, with reductions in the total lesion count at endpoint of 69.8% for CDP + BPO group and 64.5% for ERY + Zn group. Both treatments were well tolerated.

CONCLUSIONS

CDP + BPO and ERY + Zn are effective treatments for acne but CDP + BPO has an earlier onset of action that should improve patient compliance.

Guidelines of care for acne vulgaris management

DISCLAIMER

Adherence to these guidelines will not ensure successful treatment in every situation. Furthermore, these guidelines should not be deemed inclusive of all proper methods of care or exclusive of other methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific therapy must be made by the physician and the patient in light of all the circumstances presented by the individual patient.

Zinc in skin pathology and care

OBJECTIVES

To assess the significance of zinc in the etiology of various dermatological conditions and examine the role of zinc as a mode of treatment for a wide range of dermatoses.

METHODS

Review of existing literature through searches using the PubMed site with zinc and the dermatosis in question as search words.

RESULTS

Severe zinc deficiency states such as acrodermatitis enteropathica are associated with a variety of skin manifestations, such as perioral, acral and perineal dermatitis. These syndromes can be reversed with systemic zinc repletion. In addition to skin pathologies which are clearly zinc-dependent, many dermatological conditions (e.g. dandruff, acne and diaper rash) have been associated and treated with zinc. Success rates for treatment with zinc vary depending on the disease, mode of application and zinc salt used. Usually, alternative modes of treatment are superior to zinc.

CONCLUSIONS

Generally, it seems that with the exception of systemic deficiency states, there is very little evidence to convincingly demonstrate the efficacy of zinc as a first-line treatment for any dermatological conditions. Further research is needed in order to establish the indications for zinc treatment in dermatology, optimal mode of delivery, type of compound and therapeutic indexes.

A guide to antibiotic resistance in bacterial skin infections

The emergence of bacterial resistance to commonly used antibiotics is not new. In this review we have tried to cover the ever increasing problems facing the treatment and containment of bacterial skin infections. We have tried to give an overview of the varied mechanisms by which bacteria gain and spread antimicrobial resistance, whilst dealing with the patterns of resistance exhibited by some of the commonly encountered organisms. Where there is evidence, we have formulated an approach on how to tackle antibiotic resistance. Where there is a lack of evidence we have formulated what we perceive to be appropriate guidelines.

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.

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.

Topical antibacterial therapy for acne vulgaris

Topical antibiotics and benzoyl peroxide, are the two main topical antibacterial treatments indicated for mild-to-moderate acne vulgaris. Topical antibiotics act both as antibacterial agents suppressing Propionibacterium acnes in the sebaceous follicle and as anti-inflammatory agents. Benzoyl peroxide is a powerful antimicrobial agent that rapidly destroys both bacterial organisms and yeasts. Topical clindamycin and erythromycin have been proven to be effective against inflammatory acne vulgaris in concentrations of 1-4% with or without the addition of zinc. However, none of the antibacterials tested was more effective than benzoyl peroxide, which also has the advantage of not being associated with antimicrobial resistance. Topical antibacterial therapy should be discontinued once improvement is observed. If no improvement is observed within 6-8 weeks, the agent should be discontinued and a therapeutic switch considered. The primary limitation of benzoyl peroxide for some acne vulgaris patients is cutaneous irritation or dryness.Antibacterial therapy can be used in combination with other agents. Combining topical antibiotics and topical retinoids may enhance the efficacy, since the retinoid will improve the penetration of the antibiotic. Combining a topical antibiotic with benzoyl peroxide may increase the bactericidal effect of the antibiotic and reduce the potential for bacterial resistance. Topical and oral antibacterials should not be used in combination for the treatment of acne vulgaris, since this association may increase the risk of bacterial resistance.

Erganzende Verfahren in der Aknetherapie. Adjunctive acne therapies

The mainstays of modern acne therapy include comedolytic, antimicrobial, and anti-inflammatory substances, as well as antiandrogens. Additionally, traditional or newly developed therapeutic approaches may be considered, including pharmacologic (dapsone, zinc) and physical measures (phototherapy, photodynamic therapy, comedone extraction, abrasives). This article reviews such adjunctive therapies with regard to efficacy and their roles in acne therapy.

Acne: Topical treatment

Acne vulgaris is a common skin disease, affecting about 70-80% of adolescents and young adults. It is a multifactorial disease of the pilosebaceous unit.(1) The influence of androgens at the onset of adolescence leads to an enlargement of the sebaceous gland and a rise in sebum production. Additional increased proliferation and altered differentiation of the follicular epithelium eventually blocks the pilosebaceous duct, leading to development of the microcomedo as the primary acne lesion. Concomitantly and subsequently, colonization with Propionibacterium acnes increases, followed by induction of inflammatory reactions from bacteria, ductal corneocytes, and sebaceous proinflammatory agents (Fig 1).(2-5)

Topical antibacterial treatments for acne vulgaris : comparative review and guide to selection

Topical antibacterial agents are an essential part of the armamentarium for treating acne vulgaris. They are indicated for mild-to-moderate acne, and are a useful alternative for patients who cannot take systemic antibacterials. Topical antibacterials such as clindamycin, erythromycin, and tetracycline are bacteriostatic for Propionibacterium acnes, and have also been demonstrated to have anti-inflammatory activities through inhibition of lipase production by P. acnes, as well as inhibition of leukocyte chemotaxis. Benzoyl peroxide is a non-antibiotic antibacterial agent that is bactericidal against P. acnes and has the distinct advantage that thus far, no resistance has been detected against it. Combined agents such as erythromycin/zinc, erythromycin/tretinoin, erythromycin/isotretinoin, erythromycin/benzoyl peroxide, and clindamycin/benzoyl peroxide are increasingly being used and have been proven to be effective. They generally demonstrate good overall tolerability and are useful in reducing the development of antibacterial resistance in P. acnes. The selection of a topical antibacterial agent should be tailored for specific patients by choosing an agent that matches the patient's skin characteristics and acne type. Topical antibacterial agents should generally not be used for extended periods beyond 3 months, and topical antibacterials should ideally not be combined with systemic antibacterial therapy for acne; in particular, the use of topical and systemic antibacterials is to be avoided as far as possible.

Defensins and acne

Acne a disease of the pilosebaceous unit is characterised by hypercornification and hyperkeratosis of outer root sheath (ORS) and sebaceous duct and perilesional infiltrate. Lesions may be characterised as "non"-inflammatory versus inflammatory. Hypercornification of the distal ORS and the pilosebaceous duct in concert with increased sebum production and abnormalities of the microbial flora are considered to be major factors in the pathogenesis of acne vulgaris. However, the basic mechanisms involved in the development of inflammation during acne vulgaris remain unclear. We have investigated the expression patterns of two antimicrobial peptides, human beta-defensin 1 (hBD1) and human beta-defensin 2 (hBD2) in healthy human hair follicles as well as in peri- and intralesional skin of acne vulgaris lesions such as comedones, papules and pustules. Strong hBD1 and hBD2 immunoreactivity was found in all suprabasal layers of the epidermis, and all permanent compartments of the hair follicle including the distal ORS of the hair follicle and the pilosebaceous duct. Moreover, marked hBD1 and hBD2 expression was also detected in the hair follicle stem cell compartment. In contrast, the proximal follicle bulb which undergoes apoptotic regression and is also able to regenerate following injury did not express hBD1 or hBD2. The majority of acne biopsies displayed a marked upregulation of hBD2 IR in the lesional and perilesional epithelium; in particular in pustules, and a less marked upregulation of hBD1 IR. The upregulation of beta-defensins expression in acne vulgaris lesions when compared to controls suggests that beta-defensins may be involved in the pathogenesis of acne vulgaris.

Short-term effects of topical fusidic acid or mupirocin on the prevalence of fusidic acid resistant (FusR) Staphylococcus aureus in atopic eczema

BACKGROUND

Staphylococcus aureus has a role in the pathophysiology of atopic eczema. Topical fusidic acid is widely used in its treatment. There is concern that topical use of fusidic acid may be driving the selection and dissemination of fusidic acid-resistant (FusR) S. aureus.

OBJECTIVES

To test the hypothesis that treatment of atopic eczema for 2 weeks with topical fusidic acid/steroid combination can increase carriage of FusRS. aureus.

METHODS

Forty-six patients with atopic eczema were allocated randomly to one of two treatment groups. Group 1 (28 patients) were treated with topical 2% fusidic acid plus 0.1% betamethasone cream, and group 2 (18 patients) with topical 2% mupirocin and 0.1% betamethasone cream. The clinical response and nasal and skin colonization with S. aureus were recorded before treatment and after 1 and 2 weeks of therapy.

RESULTS

Baseline samples from the site of worst eczema showed S. aureus (sensitive and resistant) in 76% of patients, and FusRS. aureus in 26%, with no significant difference between treatment groups. After 1 and 2 weeks, both groups showed similar significant clinical improvement. The overall median clinical improvement was paralleled by a reduction in prevalence and population density of S. aureus (sensitive and resistant) at the worst eczema site (P < 0.0001). However, for FusRS. aureus there was no significant change in the prevalence of carriage, or population density in either group compared to baseline. Over 50% of patients carried S. aureus in the nerves and over 20% carried FusRS. aureus. Neither regimen affected either the prevalence or population density of S. aureus or FusRS. aureus in the nerves.

CONCLUSIONS

In this small study there is no evidence to support the hypothesis that short-term treatment of atopic eczema with fusidic acid/steroid combination increases fusidic acid resistant S. aureus during a 2-week period.

Is antibiotic resistance in cutaneous propionibacteria clinically relevant? : implications of resistance for acne patients and prescribers

It is well recognized that some patients with acne do not respond adequately to antibiotic therapy. It is important to distinguish antibiotic recalcitrant acne which we would suggest represents acne that shows a diminished response to treatment irrespective of the cause as opposed to 'antibiotic-resistant acne' which is acne that is less responsive to treatment as a direct consequence of skin colonization with resistant propionibacteria. Here we show that antibiotic-resistant acne is not just a theoretical possibility but a real phenomenon that could have important consequences for patients and prescribers. The relationship between skin colonization by antibiotic-resistant propionibacteria and treatment outcomes is a complex one that is explained at the follicular level by physiological differences affecting local drug concentrations. A systematic review of the literature on antibiotic-resistant propionibacteria revealed methodological shortcomings in studies of their prevalence and a paucity of evidence on their clinical significance. Despite the elucidation of resistance mechanisms in cutaneous propionibacteria, our continuing inability to distinguish between strains of Propionibacterium acnes means that we still do not fully understand how resistance spreads, although person-to-person transfer is most likely. Finally, we present a decision tree for acne management in an era of prudent antimicrobial prescribing that provides an alternative to existing treatment algorithms by placing topical retinoids and not antibiotics at the cornerstone of acne management.

Optimal management of acne to prevent scarring and psychological sequelae

Acne vulgaris is one of the most common inflammatory dermatoses and is seen in both the hospital setting and in general practice. Multiple factors are involved in the pathophysiology of acne, including: an alteration in the pattern of keratinization within the pilosebaceous follicles resulting in comedone formation; an increase in sebum production which is influenced by androgens; the proliferation of Propionibacterium acnes; and the production of perifollicular inflammation. Genetic and hormonal factors may also contribute to acne. Better understanding of the pathophysiology of the disease has led to the development of novel therapies which are directed at one or more of the implicated etiologic factors. Systemic antibiotics for acne have been the mainstay of treatment for many years. The main cause for concern following the use of systemic antibiotics is the emergence of antibiotic-resistant strains of P. acnes. Concomitant use of non-antibiotic therapies such as benzoyl peroxide helps to decrease the occurrence of resistance and can be effective in the treatment of resistant and nonresistant propionibacterial strains. However, no one agent is able to eradicate resistant strains completely and as resistant strains correlate to poor clinical response to therapy, prescribing strategies are required to minimize the occurrence of resistance to P. acnes. When assessing acne it is important to take an all embracing approach and to examine carefully for both the clinical and psychologic effects of the disease process. There are numerous forms of acne scarring and it is important to be aware of these as patients who are developing scarring merit early effective therapy. Some patients with acne will develop psychologic problems as a consequence of their condition. Even mild to moderate disease can be associated with significant depression and suicidal ideation and psychologic change does not necessarily correlate with disease severity. Acne scars themselves have been shown to produce significant psychopathology. When initiating treatment it is important to consider the aims of therapy. Treatment should be aimed at achieving clearance of acne, prevention of scarring and, where necessary, relief from any psychologic stress resulting from the acne. Therapy should be commenced early in the disease process in order to prevent scarring and it is important to select appropriate therapies according to the clinical signs and psychologic disability. It is also important to ensure that the patient is able to comply with therapy and clear guidelines regarding treatment, possible adverse effects and realistic expectations should be provided.

Human beta defensin-1 and -2 expression in human pilosebaceous units: upregulation in acne vulgaris lesions

A rich residential microflora is harboured by the distal outer root sheath of the hair follicle and the hair canal - normally without causing skin diseases. Although the basic mechanisms involved in the development of inflammation during acne vulgaris remain unclear, microbial agents might play an important role in this process. In this study we have analyzed by in situ hybridization and immunohistochemistry the expression patterns of two antimicrobial peptides, human beta defensin-1 and human beta defensin-2, in healthy human hair follicles as well as in perilesional and intralesional skin of acne vulgaris lesions such as comedones, papules, and pustules. Strong defensin-1 and defensin-2 immunoreactivity was found in all suprabasal layers of the epidermis, the distal outer root sheath of the hair follicle, and the pilosebaceous duct. Marked defensin-1 and defensin-2 immunoreactivity was also found in the sebaceous gland and in the basal layer of the central outer root sheath including the bulge region. The majority of acne biopsies displayed a marked upregulation of defensin-2 immunoreactivity in the lesional and perilesional epithelium - in particular in pustules - and a less marked upregulation of defensin-1 immunoreactivity. The upregulation of beta-defensin expression in acne vulgaris lesions compared to controls suggests that beta-defensins may be involved in the pathogenesis of acne vulgaris.

Is acne an infection of blocked pilosebaceous follicles? Implications for antimicrobial treatment

A model is proposed which is based on the assumption that acne is due to infection of functionally blocked pilosebaceous follicles by propionibacteria. Noninflamed lesions, which are first visible during the adrenarche in acne-prone individuals, do not contain propionibacteria. Comedogenesis appears to be independent of bacterial infection and may be driven by high levels of bioactive interleukin-1 alpha derived from ductal hyperkeratinocytes. The stimulus which triggers interleukin-1 alpha production is unknown. Formalin killed Propionibacterium acnes failed to stimulate production of the cytokine by cultured human keratinocytes in vitro. Inflamed lesions are thought to arise from microcomedones, but the initiating events are unknown. Evidence that propionibacteria are involved in the generation of inflammatory lesions is inconclusive. The cellular infiltrate is consistent with a type IV hypersensitivity response to one or more persistent lesional antigens, not necessarily bacterial. The potent adjuvant activity of P. acnes would up-regulate the immune response to any antigen which came into contact with the mononuclear cell infiltrate. Antibiotics are widely used in the treatment of acne, and their effects in selecting a predominantly resistant commensal population are well recognized. Although they reduce numbers of propionibacteria on the skin, other modes of action may contribute to or explain their therapeutic efficacy. At a time when there is global concern that antibiotic resistance rates in common bacterial pathogens may threaten our future ability to control bacterial infections, practices which promote the spread of antibiotic-resistant bacteria must be fully justified. A thorough reappraisal of the role of propionibacteria in acne is overdue. It is likely that further experimental work is needed to confirm or refute that P. acnes is aptly named.

In-vitro and in-vivo efficacy of zinc acetate against propionibacteria alone and in combination with erythromycin

Some studies have been published about the in vitro activity of zinc acetate (ZA), erythromycin (E) and their combination (ZA/E) against Propionibacterium spp., especially erythromycin resistant strains. The efficacy of topical ZA/E combination has been reported as well, but a comparison to ZA monotherapy is missing. Therefore, the MIC values of ZA, E and the ZA/E combination were determined for 15 erythromycin-resistant and 12 erythromycin-sensitive Propionibacterium strains using the agar dilution method and the checkerboard technique. Furthermore, the antimicrobial efficacy of ZA (1.2%) vs. the ZA/E (1.2%/4%) combination in an alcoholic solution was tested in a 7-day treatment administered to 32 acne patients. The MIC 100 for ZA was 1024 micrograms ZA/ml for both, erythromycin resistant and erythromycin sensitive Propionibacterium strains. The ZA, as well as the ZA/E solution showed efficacy reducing both the Propionibacterium spp., and the Micrococcaceae in the sebaceous gland infundibula of acne patients. There was no significant difference between the two treatments. As the MIC 100 of ZA/E was equal to the MIC 100 of ZA, the decrease of the erythromycin MIC of the ZA/E combination in erythromycin-resistant strains may be partly attributed to the addition of ZA to E. The in vivo antibacterial efficacy on 32 acne patients supports the hypothesis that the antibacterial effect of ZA/E in short-term treatment can be mostly attributed to ZA.

Acne. An overview of clinical research findings

Although acne represents the most common chronic skin condition seen by dermatologists, there are still many unanswered questions regarding its pathophysiology, and patients are still in need of more effective therapies, particularly those aimed at the hormonal aspects of acne. Recent clinical research has led to advances in our understanding of factors such as cytokines in follicular hyperkeratinization and the role of androgens in acne, the emergence and significance of antibiotic resistance of P. acnes, the long-term safety and efficacy of isotretinoin, and the safety and efficacy of new topical retinoids, such as tazarotene and adapalene. Fruitful interactions between basic scientists and clinical researchers within medicine and the pharmaceutical industry will, it is hoped, provide for future advances in this area.