Antibiotic resistance of microbial strains isolated from Korean acne patients

Over several decades, topical and systemic antibiotics have been the mainstay of treatment for acne vulgaris. The widespread and long‐term use of antibiotics in the treatment of acne has resulted in the spread of resistant bacterial strains and treatment failure. We aimed to examine the bacteriology of acne vulgaris and to evaluate its susceptibility to the antibiotics widely used for acne in Korea. We examined the species of bacteria aerobically and anaerobically isolated from 100 Korean acne patients. Among the bacteria isolated, Staphylococcus epidermidis (36 patients) was the most common, followed by Propionibacterium acnes (30 patients). Eleven strains of P. acnes (36.7%) and 25 strains of S. epidermidis (69.4%) were resistant to one or other of the antibiotics tested. A higher proportion of P. acnes isolates were resistant to clindamycin (30%) and erythromycin (26.7%), than to any other antibiotics tested (P = 0.0003). Some S. epidermidis isolates were resistant to tetracycline and doxycycline in addition to clindamycin and erythromycin. In the previous studies, few strains of P. acnes were found to be resistant to any of the antibiotics, but this study shows that antibiotic‐resistant strains have been increasing in Korea acne patients.     

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

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

Relationship between quinolone use and resistance of Staphylococcus epidermidis in patients with acne vulgaris

Staphylococcus epidermidis is a bacterium known to inhabit the skin. In treatment of acne vulgaris, the cutaneous milieu is exposed to oral or topical antimicrobials. We previously reported that the antimicrobial resistance of Cutibacterium acnes isolated from acne patients is affected by antimicrobial use. The aim of this study was to investigate the relationship between quinolone use and resistance in skin bacteria, particularly S. epidermidis, from acne patients. A total of 92 and 87 S. epidermidis strains isolated from clinic patients and hospital outpatients with acne vulgaris, respectively, were tested. No significant difference was found between the prevalence of methicillin‐resistant S. epidermidis (MRSE) strains from clinic patients (37.0%) and hospital outpatients (39.1%). The MRSE strains (20.6%, 14/68 strains) showed a significantly higher ratio of high‐level levofloxacin resistance (minimum inhibitory concentrations were 64 to ≥256 μg/mL) compared with methicillin‐susceptible S. epidermidis strains (2.7%, 3/111 strains) (P < 0.01). The rate of levofloxacin resistance in C. acnes strains, which were isolated from the same samples of acne patients, showed a strong positive correlation with that in S. epidermidis strains (r = 0.93, P < 0.01). The high‐level levofloxacin‐resistant strains were frequently found in patients with history of quinolone use compared with those without (P < 0.01). Our data showed for the first time that antimicrobial administration for acne treatment affects the antimicrobial resistance in not only C. acnes but also S. epidermidis. Thus, caution should be exercised in antimicrobial use for acne treatment to prevent increasing antimicrobial resistance in these species.     

Multicenter cross‐sectional observational study of antibiotic resistance and the genotypes of Propionibacterium acnes isolated from Chinese patients with acne vulgaris

Antibiotics are widely applied in management of acne vulgaris, which raises the issue of antibiotic resistance. Due to improper application and supervision of antibiotics, antibiotic resistance has become a serious problem in China. So, the efficacy of antimicrobial therapy in acne is unclear without an objective monitor of antibiotic resistance of Propionibacterium acnes. This cross‐sectional, multicenter observational study is aimed at understanding the status of antibiotic resistance in P. acnes, investigating the measures of acne management in China and analyzing the genotypes of antibiotic‐resistant strains of P. acnes. Altogether, 312 strains of P. acnes were collected from patients in five medical centers across central China after reviewing the corresponding medical history in detail. The samples underwent antibiotic susceptibility assays by agar dilution method with a total of 11 classes of antibiotics being tested. The antibiotic‐resistant strains were screened and further analyzed by investigation of the genotypes regarding 23S rRNA, 16S rRNA and erm(X). The predominant resistance occurred in macrolides and lincomycin with an overall resistance rate of 47.8%. The resistance to tetracyclines was scarce with only two cases identified. The emergence of minimum inhibitory concentration elevation for tetracyclines is associated with its application history (P < 0.005). The genotypes of the reported macrolide–lincosamide–streptogramin B resistance strains were also spotted in Chinese subjects while other resistance determinants may also exist. The tetracyclines have been proved to be vastly susceptible while macrolides and lincomycin face a serious resistance status in China.     

Antimicrobial susceptibility and phylogenetic analysis of Propionibacterium acnes isolated from acne patients in Japan between 2013 and 2015

The prevalence of antimicrobial‐resistant Propionibacterium acnes strains isolated from acne patients has been increasing in Japan. Here, to estimate the current resistance rate, we tested antimicrobial susceptibility among P. acnes from acne patients having visited a specialized dermatology clinic between 2013 and 2015. Rates of resistance to macrolides and clindamycin were 44.3 (31/70) and 38.6% (27/70), respectively. erm(X), which confers high‐level clindamycin resistance (minimum inhibitory concentration ≥256 μg/mL), was detected in six isolates, whereas no resistance determinants were identified in eight strains showing high‐level resistance to clindamycin. Using single‐locus sequence typing, the P. acnes isolates were classified into five clades (A, E, F, H and K), with all high‐level clindamycin‐resistant strains lacking known clindamycin resistance determinants being grouped together (in clade F). P. acnes isolates from patients previously treated with macrolides and clindamycin showed a macrolide resistance rate (55.3%) significantly higher than that of those from patients not having received these treatments (21.7%, P < 0.05). Furthermore, strains of clade F, which were very rarely isolated from healthy individuals, were more frequently recovered from patients with severe acne (40.0%) than those with mild acne (23.3%). Our data showed an increase in macrolide‐resistant P. acnes prevalence in Japan due to the use of antimicrobial agents for acne treatment. Furthermore, we identified strains of specific phylogenetic groups frequently associated with severe acne patients.     

Propionibacterium acnes (P. acnes) resistance and antibiotic use in patients attending Australian general practice

Background/Objectives: Antibiotic resistance in the community, including transfer between bacteria, is a growing concern for clinicians. Acne is commonly treated in general practice, sometimes with antibiotics. The aim of this study is to measure the rate of carriage of antibiotic resistant Propionibacterium acnes 10 years apart in general practice and the relationship of resistance to type of treatment, as well potential effects on other flora. Methods: Patients (N = 215) with acne presenting to Australian Capital Territory and south‐eastern New South Wales general practices were swabbed for P. acnes in 1997–1998 and 2007. Clinical details were collected with questionnaires. In 2007 swabs were also taken for Staphylococcus aureus and Streptococcus pneumoniae. GP's diagnostic classification of acne was tested using a set of standard photographs. Results: Resistant P. acnes was isolated from 20 patients (9%) and the proportion that was resistant was the same in 1997–1998 and in 2007. Antibiotic use, particularly topical, was associated with P. acnes resistance. Resistance rates declined with the time elapsed since ceasing antibiotics. Use of retinoids was associated with a decreased chance of growing P. acnes (P = 0.008) but not with decreased resistance. Simultaneous resistance with S. aureus was not detected, but only in 30 patients was S. aureus isolated. Conclusions: P. acnes resistance was similar in 1997–1998 and in 2007.The chance of a patient carrying a resistant strain of P. acnes is significantly greater with recent exposure to antibiotics, and clinicians should limit prescribing where possible. Resistance disappears rapidly after ceasing antibiotics. Cross resistance with other organisms was not detected in this study.     

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.     

Effects of benzoyl peroxide and erythromycin alone and in combination against antibiotic-sensitive and -resistant skin bacteria from acne patients

Topical formulations of erythromycin and benzoyl peroxide are popular and effective treatments for mild to moderate acne vulgaris. Use of the former is associated with resistance gain in both skin propionibacteria and coagulase-negative staphylococci, whereas use of the latter is not. We evaluated the efficacy of a combination of erythromycin and benzoyl peroxide against a total of 40 erythromycin-sensitive and -resistant strains of Staphylococcus epidermidis and skin propioni- bacteria in vitro. Using the checkerboard technique, five erythromycin resistant strains of Propionibacterium acnes were inhibited synergistically or additively by the combination. Complete mutual indifference was exhibited between the drugs against the remaining 35 strains. However, erythromycin resistant staphylococci and propionibacteria were inhibited by the same concentration of benzoyl peroxide as erythromycin-sensitive strains. These results suggest that, although the combination of erythromycin and benzoyl peroxide is not synergistic against the majority of erythromycin-resistant staphylococci and propionibacteria, the concomitant therapeutic use of both drugs should counteract the selection of erythromycin-resistant variants and reduce the number of pre-existing resistant organisms on the skin of acne patients.     

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.     

The antibiotic susceptibility of Propionibacterium acnes: a 15-year bacteriological study and retrospective evaluation

Propionibacterium acnes strains were isolated from the comedones of 46 acne patients, and their susceptibilities to penicillin G, ampicillin, erythromycin, clindamycin, tetracycline, doxycycline, minocycline, cephalexin and gentamycin were studied by examining their minimum inhibitory concentrations. Two additional standard strains were included in the study. In the results, differing antibiotic susceptibilities were found, and P. acnes strains were the most sensitive to erythromycin and clindamycin, followed by ampicillin and minocycline. The highest levels of resistance were observed against clindamycin, erythromycin and tetracycline. Non-resistant strains were detected only against minocycline. A comparison of these results with others obtained by similar studies in our department during the last 15 years showed a progressive tendency toward antibiotic resistance for Propionibacterium acnes, probably related to the systemic administration of antibiotics for the treatment of bacterial infections other than acne.     

IgG subclasses specific to Staphylococcus epidermidis and Propionibacterium acnes in patients with acne vulgaris

IgG subclasses specific to Staphylococcus epidermidis and Propionibacterium acnes were determined in sera from patients with mild, moderate or severe acne and from a control group. Titres specific to S. epidermidis were all within the same range and did not differ between groups. The titres of IgG subclasses specific to P. acnes did vary between groups. IgG₁ and IgG₃ were significantly higher in severe acne patients compared with moderate acne patients, while IgG₂ was significantly higher in moderate and severe patients compared with controls. Titres of IgG₄ did not differ between groups. The pattern of titres observed suggests that, while the antibody response to S. epidermidis is relatively harmless, antibodies to P. acnes may be involved in the pathogenesis of acne vulgaris.     

Bacterial resistance in French acne patients

Background The percentage of strains of Propionibacterium acnes resistant to antibiotics in acne is increasing in many countries, raising the question of the risks associated with bacterial resistance. Numerous series of cases have been published on European populations of acne patients, but at the moment we still have very few data regarding France. Objectives The aim of this study was to evaluate the prevalence of P. acnes resistant strains to erythromycin, tetracycline, and doxycycline in a population of French acne patients. Methods Specimens were collected from 273 patients in 43 centers located throughout France (12 hospitals and 31 private office practices). Results 75.1% of the patients were carriers of P. acnes strains resistant to erythromycin and 9.5% to tetracycline. One hundred percent of strains resistant to tetracycline were also resistant to doxycycline. There was no significant difference among the regions and between patients followed in hospital or private office. Conclusions It clearly appears that the percentage of patients with P. acnes strains resistant to erythromycin is similar to that in other countries, but lower for tetracycline or doxycycline in comparison to other European countries.     

Antibiotic‐resistant Propionibacterium acnes among acne patients in a regional skin centre in Hong Kong

Background There has been no study on antibiotic‐resistant Propionibacterium acnes in Hong Kong. Objective We investigated the prevalence and pattern of antibiotic‐resistant P. acnes and to identify any associated factors for harbouring the resistant strains. Methods Culture and sensitivity testing of P. acnes to commonly used antibiotics were performed. Resistance to tetracycline was defined at a minimal inhibitory concentration (MIC) of 2 μg/mL or more; erythromycin at an MIC of 0.5 μg/mL or more; clindamycin at an MIC of 0.25 μg/mL or more according to EUCAST. For breakpoints of doxycycline and minocycline, those with an MIC of 1 μg/mL or more were defined as resistant strains. Results Among the 111 specimens collected from 111 patients, 86 strains of P. acnes were recovered, one from each specimen. Twenty‐five specimens had no growth. Forty‐seven (54.8%) strains were found to be resistant to one or more antibiotics. Forty‐six (53.5%), 18 (20.9%), 14 (16.3%), 14(16.3%) and 14 (16.3%) strains were resistant to clindamycin (CL), erythromycin (EM), tetracycline (TET), doxycycline (DOX) and minocycline (MR) respectively. Ten strains (11.6%) had cross resistance between the MLS antibiotics (erythromycin or clindamycin), one strain (1.2%) had cross resistance among the cyclines and 14 strains (16.4%) had cross resistance between the MLS and cycline antibiotics. Binary logistic regression showed an association between MLS antibiotic resistance with an increased age whereas cycline resistance was associated with the duration of treatment. Conclusions Antibiotic‐resistant P. acnes is prevalent in Hong Kong. Dermatologists should be more vigilant in prescribing antibiotics for acne patients.     

Characterization of acne patients carrying clindamycin-resistant Cutibacterium acnes: A Japanese multicenter study

Use of antimicrobials for acne treatment is correlated with an increased occurrence of antimicrobial-resistant Cutibacterium acnes. To clarify the role of antimicrobial use on the resistance and to investigate the characteristics of resistant strains, we conducted a multicenter study in dermatological clinics frequently visited by new patients with acne vulgaris. We collected specimens in 264 acne patients and tested 164 C. acnes strains isolated from 164 patients visiting 13 dermatological clinics. Antimicrobial susceptibility testing showed that the rates of resistance for tetracyclines, macrolides and clindamycin were significantly higher in C. acnes strains isolated from patients using antimicrobials for acne treatment than patients not using them. In particular, clindamycin-resistant strains were frequently isolated from patients with older median age (≥24 years) and severe/moderate acne. After investigating the resistance mechanism of 15 high-level clindamycin-resistant strains, the transposable clindamycin resistance genes, erm(X) or erm(50), were detected in 14 strains. Using single-locus sequence typing for C. acnes, the strains with erm(X) or multidrug resistance plasmid pTZC1 coding erm(50) and tetracycline resistance gene tet(W) were classified into clade F, which were specifically isolated from Japanese patients with acne, except for one strain. Our data showed that patients’ information, such as antimicrobial use, age and acne severity, are valuable in estimating whether a patient carries antimicrobial-resistant C. acnes. Additionally, our results suggest that the clade F strains have a high risk of acquiring multidrug resistance.     

Antimicrobial susceptibility and genetic characteristics of Propionibacterium acnes isolated from patients with acne

Background Propionibacterium acnes is an important target in acne management. Antibiotic resistance has increased, reducing its clinical efficiency. Objective To study the prevalence, antimicrobial susceptibility patterns, and resistance mechanisms of P. acnes isolated from patients with acne. Methods Skin swabs were collected from 83 patients. Agar dilution determined the minimum inhibitory concentrations of five antibiotics. Polymerase chain reaction and DNA sequencing were used to identify mutations. Results P. acnes was isolated in 80 of 83 patients (96%), and 27 patients had resistance to antibiotics (33.7%). The mean age was older in the antibiotic‐resistant group (20.8 ± 5.8 vs. 18.3 ± 3.7, P = 0.02). Resistance to trimethoprim–sulfamethoxazole was 26.3%, erythromycin 12.5%, and clindamycin 7.5%. All clindamycin‐resistant strains had cross‐resistance to erythromycin, and 40% erythromycin‐resistant strains had cross‐resistance to trimethoprim–sulfamethoxazole. All strains were sensitive to tetracycline and doxycycline. The use of topical erythromycin or clindamycin was a risk factor to carry resistant strains (P = 0.02, P = 0.04, respectively). Resistance to trimethoprim–sulfamethoxazole was associated with acne severity (P = 0.02). Six of the 10 erythromycin‐resistant strains had a mutation in the peptidyl transferase region of the 23S rRNA gene: one A2058G and five A2059G. No strain carrying mutation G2057A was found. Conclusions Resistance to trimethoprim–sulfamethoxazole was the most common pattern found, and further studies are required to clarify its resistance mechanism. A certain tetracycline resistance was expected, but interestingly all strains remained sensitive. Resistance to erythromycin and clindamycin were influenced using topical formulations. Mutation A2059G was related to high resistance to erythromycin. Antibiotic resistance is increasing, and new strategies are needed.     

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

Background Antimicrobials are essential in acne therapy. In the last decades, Propionibacterium acnes has become resistant to different antibiotics. Objective To determine antimicrobial susceptibility patterns of P. acnes to frequently used drugs. Materials and methods Cutaneous lesion samples were obtained from 50 patients with acne vulgaris, which were cultured in anaerobic media to demonstrate the presence of P. acnes. After that, antimicrobial susceptibility tests to tetracycline, minocycline, doxycycline, erythromycin, azithromycin, clindamycin, trimethoprim/sulfamethoxazole (SXT) and levofloxacin were performed. Results In the general study group, resistance to azithromycin was 82%, the most prevalent one (P < 0.05), followed by trimethoprim/sulfamethoxazole (68%) and erythromycin (46%). On the other hand, all strains isolated were susceptible to minocycline. Resistance bias were similar when subgroups with and without the previous antimicrobial therapy were performed, finding a low prevalence of resistance to tetracyclines and levofloxacin in both groups. Conclusions In our region, P. acnes is highly resistant to azithromycin, SXT, erythromycin and clindamycin; and being very susceptible to minocycline, levofloxacin and tetracycline, in vitro in both groups: with and without the previous antibiotic use. To our knowledge, high resistance prevalence to azithromycin and SXT has never been reported.     

Antibiotic susceptibility of Propionibacterium acnes isolated from acne vulgaris in Korea

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

Different strains of Propionibacterium acnes modulate differently the cutaneous innate immunity

Acne is a chronic inflammatory illness of the pilosebaceous follicle where innate immunity plays a central role. In acne, the density of Propionibacterium acnes is increased in the pilosebaceous unit. We hypothesized that the severity of acne is not only dependent on the proliferation of P. acnes but also dependent on the pro‐inflammatory potential of P. acnes strains and consequently constitutes potential triggering factor for acne scarring. We investigated pro‐inflammatory potential of five different strains of P. acnes and P. avidum in skin explants and the preventive effect of zinc gluconate. The expression of immune markers was studied by immunohistochemistry, RT‐qPCR and ELISA. P. acnes strains modulate differently the expression of immune markers both at gene and at protein levels. P. acnes type III had the highest pro‐inflammatory potential by up‐regulating the expression of PAR‐2, TNF‐alpha, MMP‐13 and TIMP‐2, whereas P. avidum had the weakest by up‐regulating only MMP‐13 and TIMP‐2. Preincubation of zinc gluconate, which is a modulator of innate immunity, down‐regulates the expression of most immune markers induced by P. acnes, PAR‐2, TIMP‐2, up‐regulates MMP‐1, TIMP‐1. Our results demonstrate that different P. acnes strains have different inflammatory potential targeting markers of cutaneous innate immunity, and that inflammatory potential can be down‐regulated by zinc gluconate. As such, the inflammatory potential of P. acnes strains on acne skin may influence the severity of inflammatory acne lesions and scars.     

Single nucleotide polymorphisms of toll‐like receptor‐4 protect against acne conglobata

Background Former studies have shown that Propionibacterium acnes may stimulate expression of toll‐like receptor 4 (TLR4) in keratinocytes of patients with acne vulgaris. Objective To investigate the impact of single nucleotide polumorphisms (SNPs) of the TLR4 gene in acne vulgaris. Methods Genomic DNA was isolated from 191 patients with acne vulgaris and 75 healthy controls. Asp299Gly and Thr399Ile SNPs were defined after cutting of the PCR products by restriction enzymes. Sebum of lesions was cultured for P. acnes. Results No differences in SNP allele frequencies were found between patients and healthy controls. 46.5% of carriers of wild‐type alleles were suffering from acne conglobata compared with 28.6% of carriers of SNP alleles (P = 0.040). After adjusting for gender, family history of acnes, intake of any therapy and skin isolation of P. acnes, carriage of TLR4 gene SNPs was the only independent variable linked with a protective role against acne conglobata (OR = 0.269, P = 0.014). No differences were found in the amount of pro‐inflammatory cytokines released by peripheral blood mononuclear cells isolated from patients with acne conglobata carrying only wild‐type alleles and SNP alleles. Conclusions Carriage of gene SNPs is protective against the development of acne conglobata even in the presence of P. acnes.     

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.