In vitro antimicrobial susceptibility of Propionibacterium acnes isolated from acne patients in northern Mexico

Nitrocellulose for Prolonged Permeation of Levofloxacin HCl-Salicylic Acid In Situ Gel

Currently, the application of solvent exchange-induced in situ gel is underway for drug delivery to the body target site. Nitrocellulose was attempted in this research as the matrix-forming agent in solvent exchange-induced in situ gel for acne and periodontitis treatments. The gel incorporated a combination of 1% w/w levofloxacin HCl and 2% w/w salicylic acid as the active compounds. In order to facilitate formulation development, the study explored the matrix-forming behavior of different concentrations of nitrocellulose in N-methyl pyrrolidone (NMP). Consequently, their physicochemical properties and matrix-forming behavior, as well as antimicrobial and anti-inflammatory activities, were evaluated using the agar cup diffusion method and thermal inhibition of protein denaturation in the egg albumin technique, respectively. All prepared formulations presented as clear solutions with Newtonian flow. Their contact angles on agarose gel were higher than on a glass slide due to matrix formation upon exposure to the aqueous phase of agarose, with an angle of less than 60° indicating good spreadability. Nitrocellulose concentrations exceeding 20% initiated stable opaque matrix formation upon contact with phosphate buffer pH 6.8. The high hardness and remaining force of the transformed gel indicated their robustness after solvent exchange. Fluorescence tracking using sodium fluorescein and Nile red confirmed the retardation of NMP and water diffusion by the nitrocellulose matrix. From the Franz cell permeation study, these drugs could permeate through neonate porcine skin and tissue of porcine buccal from the nitrocellulose in situ forming gel. Their accumulation in these tissues might enable the inhibition of the invading bacterial pathogens. The developed in situ gels effectively inhibited Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes, and Porphyromonas gingivalis. Furthermore, the formulations demonstrated an anti-inflammatory effect. The low viscosity of LvSa25Nc makes it appropriate for injectable treatments targeting periodontitis, while the higher viscosity of LvSa40Nc renders it appropriate for topical applications in acne treatment. Therefore, the nitrocellulose in situ gel loaded with combined levofloxacin HCl and salicylic acid emerges as a promising dosage form for treating acne and periodontitis.

A cross-sectional study examining the prevalence of antibiotic-resistant Cutibacterium acnes isolated from patients with acne in Bangkok, Thailand

Cutibacterium acnes is associated with the pathogenesis of acne vulgaris (AV). The relationship between antibiotic-resistant C. acnes and AV remains unclear. The authors aimed to determine the prevalence of antibiotic-resistant C. acnes and investigate the association of acne severity with topical and systemic treatments in patients with acne. Samples were collected of inflammatory and noninflammatory acne, including closed and open comedones and erythematous papules/pustules from the face of patients with mild to severe acne. The samples were cultured under anaerobic conditions for the isolation of C. acnes. Antibiotic susceptibility tests for erythromycin, tetracycline, doxycycline, clindamycin, and trimethoprim/sulfamethoxazole were performed using the agar dilution method. From 153 patients, 143 viable C. acnes samples were isolated (93.5%). They were found resistant to trimethoprim/sulfamethoxazole (143/143, 100%), clindamycin (108/143, 75.5%), erythromycin (105/143, 73.4%), tetracycline (74/143, 51.7%), and doxycycline (73/143, 51.1%). There was no significant correlation between the prevalence of antibiotic resistance and acne severity. High-level resistant C. acnes correlated with higher clinical severity of acne in patients taking doxycycline (τ_b  = 0.3). The present prevalence of antibiotic-resistant C. acnes was high in Thailand. Antibiotic stewardship in AV treatment should be encouraged to prevent further antibiotic resistance crises.

Microbiomes in Acne Vulgaris and Their Susceptibility to Antibiotics in Indonesia: A Systematic Review and Meta-Analysis

Hot and humid countries such as Indonesia have a higher prevalence of acne vulgaris (AV). The activity of skin microbes, not only Cutibacterium acnes, contribute to the formation of AV. Topical and oral antibiotics are routinely prescribed to treat AV. As antimicrobial resistance rates increase globally, there are concerns about decreased efficacy. This study intends to systematically evaluate the microbiomes isolated from AV lesions and their antibiotics susceptibility in Indonesia. The data were retrieved through PubMed, EMBASE, Google Scholar, and ScienceDirect searches for articles published until July 2022 using three multiword searches. Sixteen studies published between 2001 and 2022 were identified from which the data were pooled using a random effects model. The pooled prevalence estimates demonstrated that C. acnes, Staphylococcus epidermidis, and Staphylococcus aureus were the three common microbes associated with AV in Indonesia. Tetracyclines had lower resistance rates compared to those of macrolides and clindamycin, with C. acnes showing a resistance rate that is as high as 60.1% against macrolides. C. acnes resistance against minocycline showed an increasing trend, whereas the resistances to doxycycline, clindamycin, and macrolides stagnated. The high resistance prevalence and trends signify a public health concern. The results of this study call for the development of antibiotic stewardship programs in Indonesia, which may lead to improved acne outcomes.

Cutibacterium Acnes Tetracycline Resistance Profile in Patients with Acne Vulgaris, in a Colombian Dermatologic Center

INTRODUCTION

Acne is a chronic inflammatory disease, in which different events intervene in its pathogenesis, one of which is Cutibacterium acnes (C. acnes). Resistance of this bacteria to different antimicrobials used in treatment has been described in different regions of the world. The purpose of the study is to estimate the resistance of C. acnes to cyclins in patients with moderate and severe acne over 18 years of age.

MATERIALS AND METHODS

An analytical cross-sectional study was carried out. Samples were taken from inflammatory lesions with a comedone extractor. The content of the samples was incubated in an anaerobic atmosphere to grow C. acnes. Finally, the susceptibility of C. acnes to tetracycline, minocycline and doxycycline was determined.

RESULTS

Samples were taken from 147 patients, of which 129 showed growth of C. acnes, finding that 5.43% of the strains were resistant to tetracycline, 5.43% to doxycycline, 0.78% to minocycline and cross resistance between doxycycline and tetracycline in all the cases. An association was found between resistance and being 25 years of age or older. No association was found with the prior use of antibiotics, a history of misuse of oral or topical antibiotics, and other demographic and clinical characteristics evaluated.

CONCLUSIONS

The resistance found of C. acnes to cyclines was lower than that reported in other studies. Although no relationship was found with the previous use of antibiotics, it is a factor described in previous studies, which is why the proper use of antibiotics is imperative to avoid the appearance of resistance.

Association of Antimicrobial Susceptibility and Treatment Outcome in Acne Vulgaris Patients: A Pilot Study

Purpose   Cutibacterium acnes ( C. acnes ) is an emerging pathogen that is highly resistant to antibiotics and is capable of causing persistent infections that are difficult to treat.

Methods & Materials  Acne vulgaris patients visiting dermatology OPD of our tertiary care hospital during the study period of 2 months were recruited. Skin swabs were collected, and the sample was processed on 5% sheep-blood agar for anaerobic culture by the GasPak method. Isolates were identified by the standard biochemical test. Antimicrobial susceptibility testing was performed for clinically relevant antibiotics by the E-strip method. The clinical response was evaluated after 1-month follow-up to the prescribed antibiotics.

Results  Minocycline, doxycycline, ceftriaxone, and tetracycline were the most effective antibiotics. Nonsusceptibility to clindamycin and erythromycin were observed in 11.9% and 31% isolates, respectively, with 9.5% isolates being nonsusceptible to both. For none of the antibiotics we found significant difference in the proportion of susceptible and nonsusceptible isolates between mild, moderate, and severe grades of acne vulgaris. For none of the antibiotic regimens, significant difference was observed between nonresponders and responders. Twenty-seven patients received clindamycin and among them 16 of 19 responders and 6 of 8 nonresponders yielded growth of clindamycin-susceptible isolates ( p = 0.57).

Conclusion  We observed significant prevalence of resistant strains of C. acnes among patients with acne vulgaris. No association was observed between in vitro susceptibility results and treatment outcome.

Reviewing the global burden of acne: how could we improve care to reduce the burden?

Acne (also known as acne vulgaris) remains the most common inflammatory dermatosis treated worldwide, as estimated by global skin disease prevalence studies. Latest reports suggest that the prevalence may be increasing in adolescents and adults, particularly female adults. The concept of 'burden of skin disease' is multidimensional and can be difficult to quantify in light of different healthcare systems across the globe. In acne, the resulting burden may vary according to patient demographics, access to treatments and duration of the disease. The visible nature of acne, symptoms and sequelae all contribute physically and psychosocially to the overall burden of disease, as do the costs required for management. Acne typically presents in adolescence at a time of significant transition. Profound effects on functional status have been demonstrated, along with a strong impact on interpersonal relationships, social functioning and mental health. The high prevalence of acne also presents an economic burden for society. The widespread and prolonged use of antibiotics introduces a potential added burden through resulting antimicrobial resistance. A James Lind Alliance Acne Priority Setting Partnership has identified numerous areas to inform future research, which would help to improve acne management and reduce the burden. The lack of standardized assessments is a major issue in acne trials and challenges the ability to compare treatments and perform meta-analyses. This paper reviews the current literature on burden of acne, identifies areas of treatment uncertainties and summarizes the work of the Acne Core Outcome Research Network as a means of supporting a reduction in the burden of disease.

Antibiotic resistance in acne: changes, consequences and concerns

Antibiotic resistance in acne was first observed in the 1970s and has been a major concern in dermatology since the 1980s. The resistance rates and types of antimicrobials have subsequently shown great variations in regions and countries. Illustrative of this is the resistance to topical erythromycin and clindamycin which continues to be a problem worldwide, while resistance to systemic treatment with tetracyclines has remained low during the past decade. The resistance for the newer macrolides like azithromycin and clarithromycin has been increasing. The results of antibiotic resistance may include treatment failure of acne, disturbance of skin microbiota, induction of opportunistic pathogens locally and systemically, and dissemination of resistant strains to both healthcare personnel and the general population. The ensuing complications, such as aggravated opportunistic infections caused by Propionibacterium acnes and the emergence of multiresistant superbugs, have not yet been confirmed.

Minocycline, focus on mechanisms of resistance, antibacterial activity, and clinical effectiveness: Back to the future

OBJECTIVES

The increasing crisis regarding multidrug-resistant (MDR) and extensively drug-resistant microorganisms leads to appealing therapeutic options.

METHODS

During the last 30 years, minocycline, a wide-spectrum antimicrobial agent, has been effective against MDR Gram-positive and Gram-negative bacterial infections. As with other tetracyclines, the mechanism of action of minocycline involves attaching to the bacterial 30S ribosomal subunit and preventing protein synthesis.

RESULTS

This antimicrobial agent has been approved for the treatment of acne vulgaris, some sexually transmitted diseases and rheumatoid arthritis. Although many reports have been published, there remains limited information regarding the prevalence, mechanism of resistance and clinical effectiveness of minocycline.

CONCLUSION

Thus, we summarize here the currently available data concerning pharmacokinetics and pharmacodynamics, mechanism of action and resistance, antibacterial activity and clinical effectiveness of minocycline.

Potential Role of the Microbiome in Acne: A Comprehensive Review

Acne is a highly prevalent inflammatory skin condition involving sebaceous sties. Although it clearly develops from an interplay of multiple factors, the exact cause of acne remains elusive. It is increasingly believed that the interaction between skin microbes and host immunity plays an important role in this disease, with perturbed microbial composition and activity found in acne patients. Cutibacterium acnes (C. acnes; formerly called Propionibacterium acnes) is commonly found in sebum-rich areas and its over-proliferation has long been thought to contribute to the disease. However, information provided by advanced metagenomic sequencing has indicated that the cutaneous microbiota in acne patients and acne-free individuals differ at the virulent-specific lineage level. Acne also has close connections with the gastrointestinal tract, and many argue that the gut microbiota could be involved in the pathogenic process of acne. The emotions of stress (e.g., depression and anxiety), for instance, have been hypothesized to aggravate acne by altering the gut microbiota and increasing intestinal permeability, potentially contributing to skin inflammation. Over the years, an expanding body of research has highlighted the presence of a gut–brain–skin axis that connects gut microbes, oral probiotics, and diet, currently an area of intense scrutiny, to acne severity. This review concentrates on the skin and gut microbes in acne, the role that the gut–brain–skin axis plays in the immunobiology of acne, and newly emerging microbiome-based therapies that can be applied to treat acne.

Acne, the Skin Microbiome, and Antibiotic Treatment

Acne vulgaris is a chronic skin disorder involving hair follicles and sebaceous glands. Multiple factors contribute to the disease, including skin microbes. The skin microbiome in the follicle is composed of a diverse group of microorganisms. Among them, Propionibacterium acnes and Malassezia spp. have been linked to acne development through their influence on sebum secretion, comedone formation, and inflammatory response. Antibiotics targeting P. acnes have been the mainstay in acne treatment for the past four decades. Among them, macrolides, clindamycin, and tetracyclines are the most widely prescribed. As antibiotic resistance becomes an increasing concern in clinical practice, understanding the skin microbiome associated with acne and the effects of antibiotic use on the skin commensals is highly relevant and critical to clinicians. In this review, we summarize recent studies of the composition and dynamics of the skin microbiome in acne and the effects of antibiotic treatment on skin microbes.

The susceptibility of pathogens associated with acne vulgaris to antibiotics

BACKGROUND Acne vulgaris is a pilosebaceous disorder. Bacterial activity and inflammation both influence acne formation. Antibiotics suppress the bacterial activities and elicit anti-inflammatory effects. The overuse of antibiotics may lead to resistance in bacteria. This study was aimed to provide an overview of bacteria that may cause acne and determine their susceptibility to antibiotics.METHODS This was a cross-sectional study sampling from 93 patients with acne in Ciptomangunkusumo Hospital. Comedones were extracted and cultured on Brucella blood agar, under aerobic and anaerobic conditions at 35oC for 24–48 hours. Bacterial identification was performed using Vitek®, and susceptibility test using E-test. Data interpretation was based on the Clinical and Laboratory Standards Institute 2015.RESULTS Staphylococcus epidermidis (50.5%), Propionibacterium acnes (11.0%), and Staphylococcus aureus (7.7%) were identified. Bacteria were not found in 69.2% and 1.1% of samples in anaerobic and aerobic cultures, respectively. P. acnes was susceptible to doxycycline (100%) and minocycline (100%), while 10% was resistant to erythromycin, clindamycin, and tetracycline. S. epidermidis was susceptible to minocycline (100%); but resistant to erythromycin (65.2%), clindamycin (52.2%) and tetracycline (32.6%). The susceptibility of S. epidermidis to doxycycline was 89.1%, which was lower than that of P. acnes (100%). S. aureus was found to be sensitive to minocycline (100%), doxycycline (71.4%), clindamycin (71.4%), and tetracycline (71.4%); but it was resistant to erythromycin (42.9%).CONCLUSIONS Doxycycline and minocycline showed 100% effectiveness for P. acnes. The isolated bacteria were more susceptible to doxycycline compared to tetracycline. The use of clindamycin and erythromycin needs to be limited as most S. epidermidis isolates were resistant to both.

Acne antibiotic prescription pattern in Colombia

BACKGROUND

Bacterial resistance to antibiotics has been growing exponentially. Acne is the most common outpatient complains in dermatology, and involve the use of antibiotics for treatment.

METHODS

We conducted a drug utilization study, with a retrospective and descriptive design, in order to evaluated the antibiotic prescription pattern for acne vulgaris patients who were cared for the first time in 2015, and were prescribed with an antibiotic, no matter if it was topical, oral or both, and compared it against the Colombian clinical practice guidelines valid for that year in our country.

RESULTS

Three hundred sixty-nine patients were randomly collected, 221 women and 148 men. There were a correct adherence to guidelines in election of an antibiotic, its dosage, and time of use in 51.7%, 94.85%, and 76.1%, respectively. 37.1% of patients has being correctly prescribe globally, taking into consideration the three previously describe variables.

CONCLUSIONS

A no adherent antibiotic prescription was documented for less than half of the patients. In almost a quarter of the patients it was not prescribed for the right time and in most patients the correct dose was chosen. It is important to know the prescription pattern as it allows decisions to be made that lead to an adequate use of antibiotics, and thus prevent the development of antimicrobial resistance.

Antibiotic susceptibility of Propionibacterium acnes isolated from patients with acne in a public hospital in Southwest China: prospective cross-sectional study

OBJECTIVE

Antibiotics have been routinely used for several decades against Propionibacterium acnes (P. acnes), but antibiotic resistance of P. acnes is becoming a global problem. Only one related Chinese study is available. The aim of this study was to assess the antibiotic susceptibility of P. acnes obtained from patients with acne in Southwest China.

DESIGN

This was a prospective cross-sectional study. Cutaneous samples were obtained from acne lesions on the face of 375 patients. Samples were cultured in anaerobic medium to identify the presence of P. acnes. Susceptibility tests of isolated P. acnes were performed for tetracycline, doxycycline, clindamycin, erythromycin, azithromycin and clarithromycin using the Epsilometer test.

RESULTS

P. acnes was isolated from 227 patients; 224 isolates (98.7%) were susceptible to doxycycline and 220 (96.9%) were susceptible to tetracycline, followed by clindamycin and clarithromycin in 101 (44.5%) and 102 (44.93%) isolates, respectively. Susceptibility of P. acnes was detected for erythromycin in 96 (42.3%) patients, followed by azithromycin in 94 (41.4%). Subjects who received antibiotics (topical and oral) had higher frequencies of antibiotic-resistant P. acnes as well as increased antibiotic minimum inhibitory concentrations compared with patients without antibiotic treatment.

CONCLUSIONS

P. acnes was highly sensitive to cyclines (doxycycline and tetracycline). P. acnes showed higher resistance rates to macrolides-lincosamides-streptogramins antibiotics (such as erythromycin, azithromycin, clarithromycin and clindamycin). The irrational use of antibiotics for acne treatment is probably a problem in China and elsewhere. These results suggest that dermatologists should be more prudent in prescribing antibiotics for acne.

Recent advances in understanding Propionibacterium acnes ( Cutibacterium acnes) in acne

The skin commensal Propionibacterium acnes, recently renamed Cutibacterium acnes, along with the other major pathophysiological factors of increased seborrhea, hyperkeratinization of the pilosebaceous unit, and inflammation, has long been implicated in the pathogenesis of acne. Recent advances have contributed to our understanding of the role of P. acnes in acne. Although there are no quantitative differences in P. acnes of the skin of patients with acne compared with controls, the P. acnes phylogenic groups display distinct genetic and phenotypic characteristics, P. acnes biofilms are more frequent in acne, and different phylotypes may induce distinct immune responses in acne. P. acnes plays a further important role in the homeostasis of the skin’s microbiome, interacting with other cutaneous commensal or pathogenic microorganisms such as Staphylococcus epidermidis, Streptococcus pyogenes, and Pseudomonas species. In the era of increasing antimicrobial resistance, the selection of acne treatment targeting P. acnes and the prevention of antibiotic resistance play a key role in improving outcomes in acne patients and public health.

In vitro emergence of fluoroquinolone resistance in Cutibacterium (formerly Propionibacterium) acnes and molecular characterization of mutations in the gyrA gene

In vitro occurrence of levofloxacin (LVX) resistance in C. acnes and characterization of its molecular background were investigated. The mutation frequency was determined by inoculation of 10⁸ cfu of C. acnes ATCC 11827 (LVX MIC = 0.25 mg/L) on LVX-containing agar plates. The progressive emergence of resistance was studied by a second exposure to increasing LVX concentrations. For mutants, the QRDR regions including the gyrA and parC genes were sequenced and compared to both C. acnes ATCC 11827 and C. acnes KPA171202 reference sequences (NC006085). The importance of the efflux pump system in resistance was investigated by using inhibitors on selected resistant mutants with no mutation in the QRDR. C. acnes growth was observed on LVX-containing plates with mutation frequencies of 3. 8 cfu × 10^-8 (8 × MIC) and 1.6 cfu × 10^-7 (4 × MIC). LVX resistance emerged progressively after one-step or two-step assays. In LVX-resistant isolates, the MIC ranged from 0.75 to >32 mg/L. Mutations were detected exclusively in the gyrA gene. Ten genotypes were identified: G99 C, G99 D, D100N, D100 H, D100 G, S101L, S101W, A102 P, D105 H and A105 G. Mutants S101L and S101W were always associated with a high level of resistance. Mutants with no mutation in the QRDR were more susceptible when incubated with an efflux pump inhibitor (phenyl-arginine β-naphthylamide) only, suggesting, for the first time, the expression of such a system in C. acnes LVX-resistant mutants.

Propionibacterium acnes Susceptibility and Correlation with Hemolytic Phenotype

BACKGROUND

Many studies have noted an increase in the number of recognized cases of invasive infections due to Propionibacterium acnes, especially after shoulder replacement surgery. The increase in the number of recognized cases of P. acnes, a nonspore-forming, anaerobic, Gram-positive organism, appears due to both an increase in the number of shoulder operations being performed and more specimens being sent for anaerobic cultures. Nevertheless, the optimal surgical and antibiotic management of P. acnes remains controversial.

METHODS

We tested the susceptibility of 106 P. acnes strains from sterile body sites collected at the Erie County Medical Center between 2012 and 2015, using Etest gradient antibiotic strips.

RESULTS

P. acnes is very susceptible to the penicillins and the first-generation cephalosporins. We noted an association between hemolytic phenotype on Brucella Blood Agar and clindamycin resistance.

CONCLUSIONS

Antimicrobial susceptibility testing of P. acnes should no longer just be confined to the research laboratory but expanded and incorporated into routine microbiological evaluation of P. acnes. This would improve patient care as well as help clarify the relationship between hemolysis and clindamycin resistance.

Comparison effect of azithromycin gel 2% with clindamycin gel 1% in patients with acne

Background:

Acne vulgaris is the most common skin disease. Local and systemic antimicrobial drugs are used for its treatment. But increasing resistance of Propionibacterium acnes to antibiotics has been reported.

Materials and Methods:

In a double-blind clinical trial, 40 patients with mild to moderate acne vulgaris were recruited. one side of the face was treated with Clindamycin Gel 1% and the other side with Azithromycin Topical Gel 2% BID for 8 weeks and then they were assessed.

Results:

Average age was 21. 8 ± 7 years. 82.5% of them were female. Average number of papules, pustules and comedones was similarly reduced in both groups and, no significant difference was observed between the two groups (P > 0.05, repeated measurs ANOVA). The mean indexes of ASI and TLC also significantly decreased during treatment in both groups, no significant difference was observed between the two groups. (P > 0.05, repeated measurs ANOVA). Also, impact of both drugs on papules and pustules was 2-3 times greater than the effect on comedones. Average satisfaction score was not significant between the two groups (P = 0.6, repeated measurs ANOVA). finally, frequency distribution of complications was not significant between the two groups (P > 0.05, Fisher Exact test).

Conclusion:

Azithromycin gel has medical impact at least similar to Clindamycin Gel in treatment of mild to moderate acne vulgaris, and it may be consider as suitable drug for resistant acne to conventional topical therapy.

Cross-sectional Pilot Study of Antibiotic Resistance in Propionibacterium Acnes Strains in Indian Acne Patients Using 16S-RNA Polymerase Chain Reaction: A Comparison Among Treatment Modalities Including Antibiotics, Benzoyl Peroxide, and Isotretinoin

BACKGROUND

Antibiotic resistance is a worldwide problem in acne patients due to regional prescription practices, patient compliance, and genomic variability in Propionibacterium acnes, though the effect of treatment on the resistance has not been comprehensively analyzed.

AIMS

Our primary objective was to assess the level of antibiotic resistance in the Indian patients and to assess whether there was a difference in the resistance across common treatment groups.

SUBJECTS AND METHODS

A cross-sectional, institutional based study was undertaken and three groups of patients were analyzed, treatment naïve, those on antibiotics and patients on benzoyl peroxide (BPO) and/isotretinoin. The follicular content was sampled and the culture was verified with 16S rRNA polymerase chain reaction, genomic sequencing, and pulsed-field gel electrophoresis. Minimum inhibitory concentration (MIC) assessment was done for erythromycin (ERY), azithromycin (AZI), clindamycin (CL), tetracycline (TET), doxycycline (DOX), minocycline (MINO), and levofloxacin (LEVO). The four groups of patients were compared for any difference in the resistant strains.

RESULTS

Of the 52 P. acnes strains isolated (80 patients), high resistance was observed to AZI (100%), ERY (98%), CL (90.4%), DOX (44.2%), and TETs (30.8%). Low resistance was observed to MINO (1.9%) and LEVO (9.6%). Statistical difference was seen in the resistance between CL and TETs; DOX/LEVO and DOX/MINO (P < 0.001). High MIC90 (≥256 μg/ml) was seen with CL, macrolides, and TETs; moreover, low MIC90 was observed to DOX (16 μg/ml), MINO (8 μg/ml), and LEVO (4 μg/ml). Though the treatment group with isotretinoin/BPO had the least number of resistant strains there was no statistical difference in the antibiotic resistance among the various groups of patients.

CONCLUSIONS

High resistance was seen among the P. acnes strains to macrolides-lincosamides (AZI and CL) while MINO and LEVO resistance was low.

Systematic review of antibiotic resistance in acne: an increasing topical and oral threat

Topical and oral antibiotics are routinely used to treat acne. However, antibiotic resistance is increasing, with many countries reporting that more than 50% of Propionibacterium acnes strains are resistant to topical macrolides, making them less effective. We reviewed the current scientific literature to enable proposal of recommendations for antibiotic use in acne treatment. References were identified through PubMed searches for articles published from January, 1954, to March 7, 2015, using four multiword searches. Ideally, benzoyl peroxide in combination with a topical retinoid should be used instead of a topical antibiotic to minimise the impact of resistance. Oral antibiotics still have a role in the treatment of moderate-to-severe acne, but only with a topical retinoid, benzoyl peroxide, or their combination, and ideally for no longer than 3 months. To limit resistance, it is recommended that benzoyl peroxide should always be added when long-term oral antibiotic use is deemed necessary. The benefit-to-risk ratio of long-term antibiotic use should be carefully considered and, in particular, use alone avoided where possible. There is a need to treat acne with effective alternatives to antibiotics to reduce the likelihood of resistance.

[Bacterial resistance in acne? A meta-analysis of the controversy]

BACKGROUND

Acne is one of the dermatological pathologies with the highest incidence around the world. It is a multifactorial disease and its treatment can be complex. Propionibacterium acnes play a key role in the inflammation of this dermatosis. Topical antibiotics, including mainly erythromycin and clindamycin, have been used, but there is controversy over their use due to the widely documented bacterial resistance. For this reason a meta-analysis of the publications over the past 10 years is presented in order to confirm this hypothesis.

MATERIAL AND METHODS

A search was made of the publications over the past 10 years that included the results of antibiogams of patients with acne. MeSH type searches were performed with the terms "acne vulgaris", "Propionibacterium acnes", "topical administration", "treatment", "erythromycin", "clindamycin", "nadifloxacin", "antibacterial agent", "bacterial drug resistance" in PubMed, Ovid, EBSCO, Cochrane, ScienceDirect and ClinicalKey meta-searches.

RESULTS

A total of 13 articles were found that met the inclusion criteria. The mean odds ratio (OR 1.24, 95% CI) of the articles showed a slight tendency toward resistance of Propionibacterium acnes.

CONCLUSIONS

An increase in bacterial resistance to topical erythromycin and clindamycin can be confirmed, thus the use of these antibiotics is recommended in selective cases for short periods, and in combination with benzoyl peroxide for the best clinical outcome in patients with acne vulgaris.

Propionibacterium acnes: from commensal to opportunistic biofilm-associated implant pathogen

Propionibacterium acnes is known primarily as a skin commensal. However, it can present as an opportunistic pathogen via bacterial seeding to cause invasive infections such as implant-associated infections. These infections have gained more attention due to improved diagnostic procedures, such as sonication of explanted foreign materials and prolonged cultivation time of up to 14 days for periprosthetic biopsy specimens, and improved molecular methods, such as broad-range 16S rRNA gene PCR. Implant-associated infections caused by P. acnes are most often described for shoulder prosthetic joint infections as well as cerebrovascular shunt infections, fibrosis of breast implants, and infections of cardiovascular devices. P. acnes causes disease through a number of virulence factors, such as biofilm formation. P. acnes is highly susceptible to a wide range of antibiotics, including beta-lactams, quinolones, clindamycin, and rifampin, although resistance to clindamycin is increasing. Treatment requires a combination of surgery and a prolonged antibiotic treatment regimen to successfully eliminate the remaining bacteria. Most authors suggest a course of 3 to 6 months of antibiotic treatment, including 2 to 6 weeks of intravenous treatment with a beta-lactam. While recently reported data showed a good efficacy of rifampin against P. acnes biofilms, prospective, randomized, controlled studies are needed to confirm evidence for combination treatment with rifampin, as has been performed for staphylococcal implant-associated infections.

Antimicrobial susceptibility of Propionibacterium acnes isolates from acne patients in Colombia

BACKGROUND

The increasing prevalence of antimicrobial resistance in Propionibacterium acnes poses a significant challenge to successful treatment outcomes in acne patients. Although P. acnes resistance has been demonstrated throughout the world, no previous data regarding the antimicrobial susceptibility of P. acnes in Colombia are available.

OBJECTIVES

The aim of this study was to determine the antimicrobial susceptibility of P. acnes to common antibiotics used in the treatment of acne in a Colombian population.

METHODS

Samples were collected from facial acne lesions of 100 dermatology patients. All samples were cultured in anaerobic conditions, and final identification of isolates was performed. Isolates of P. acnes were then subjected to antimicrobial susceptibility tests using erythromycin, clindamycin, tetracycline, doxycycline, and minocycline.

RESULTS

Propionibacterium acnes isolates resistant to erythromycin (35%), clindamycin (15%), doxycycline (9%), tetracycline (8%), and minocycline (1%) were observed. Isolates with cross-resistance were also observed (to erythromycin and clindamycin [12%] and to doxycycline and tetracycline [6%]). Overall, 46% of isolates taken from patients with a history of antibiotic use demonstrated resistance, whereas 29% of isolates taken from patients who had never used antibiotics demonstrated resistance.

CONCLUSIONS

Antimicrobial resistance in P. acnes in this Colombian population has a lower prevalence than those reported in Europe and follows a similar pattern to findings elsewhere in Latin America. Resistance is demonstrated even in isolates from patients with no previous history of antibiotic use. Resistance to erythromycin is most commonly observed. Minocycline emerges as the most effective antibiotic.

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.

New antibiotic therapies for acne and rosacea

Acne and rosacea compromise a substantial portion of the dermatology clinical practice. Over the past century, many treatment modalities have been introduced with antibiotics playing a major role. Today, both oral and topical antibiotics are used in the management of acne and rosacea, with several novel formulations and/or combination regimens recently introduced. The latest studies suggest anti-inflammatory actions to be the most likely mechanism of antibiotics in acne and rosacea, shifting the focus to subantimicrobial-dose oral antibiotics and/or topical antibiotic regimens as the preferred first-line agents. Here we will discuss the most recent oral and topical antibiotic therapies available for treatment of acne and rosacea, with special focus on efficacy data, indication, dosing, and mechanism of action.

Antibiofilm effects of azithromycin and erythromycin on Porphyromonas gingivalis

Antibiotic resistance of biofilm-grown bacteria contributes to chronic infections, such as marginal and periapical periodontitis, which are strongly associated with Porphyromonas gingivalis. Concurrent azithromycin (AZM) administration and mechanical debridement improve the clinical parameters of periodontal tissue in situ. We examined the in vitro efficacy of AZM against P. gingivalis biofilms. The susceptibilities of adherent P. gingivalis strains 381, HW24D1, 6/26, and W83 to AZM, erythromycin (ERY), ampicillin (AMP), ofloxacin (OFX), and gentamicin (GEN) were investigated using a static model. The optical densities of adherent P. gingivalis cells were significantly decreased by using AZM and ERY at sub-MIC levels compared with those of the controls in all the strains tested, except for the effect of ERY on strain W83. AMP and OFX inhibited P. gingivalis adherent cells at levels over their MICs, and GEN showed no inhibition in the static model. The effects of AZM and ERY against biofilm cells were investigated using a flow cell model. The ATP levels of P. gingivalis biofilms were significantly decreased by AZM at concentrations below the sub-MICs; however, ERY was not effective for inhibition of P. gingivalis biofilm cells at their sub-MICs. Furthermore, decreased density of P. gingivalis biofilms was observed three-dimensionally with sub-MIC AZM, using confocal laser scanning microscopy. These findings suggest that AZM is effective against P. gingivalis biofilms at sub-MIC levels and could have future clinical application for oral biofilm infections, such as chronic marginal and periapical periodontitis.