Correlation Between Serum 25‐Hydroxyvitamin D and Virulence Genes of Staphylococcus aureus Isolates Colonizing Children with Atopic Dermatitis

The skin of children with atopic dermatitis (AD) is colonized with Staphylococcus aureus more frequently than that of their peers. We investigated the prevalence of skin and nares colonization by S. aureus in children with AD, the virulence genes of the isolates, and their association with allergy, AD severity, and serum vitamin D (25(OH)D). This was an observational, cross‐sectional study in a sample of children diagnosed with AD in two settings in Spain. The samples were collected in 2012. Swabs from affected skin and nares were taken for microbiologic culture. The prevalence of S. aureus and presence of 17 staphylococcal virulence genes were studied using polymerase chain reaction. A total of 114 patients with a mean age of 5.7 ± 4.1 (range 3 mos to 14 yrs) were included in the study. Swabs were taken from the skin of 113 individuals with AD and from the nares of 85; 28.3% had S. aureus on the skin, which was significantly associated with positive allergen‐specific immunoglobulin E antibodies and higher Scoring Atopic Dermatitis (SCORAD) scores in the multivariate analysis. The presence of virulence factors tsst‐1, eta, cna, aur, and sec in cutaneous S. aureus isolates was associated with lower serum levels of 25(OH)D. S. aureus on nasal swabs correlated with its presence on the skin and was associated with lower 25(OH)D levels. In conclusion, S. aureus colonization is associated with allergy and severity in AD, whereas certain virulence genes are associated with lower serum 25(OH)D levels.     

Bacteriological aspects of Darier’s disease

Background There are no established data on the prevalence of bacterial colonization of lesional skin, nares and perineum in Darier’s disease (DD), or its contribution to the clinical manifestations of the disease. Objective To determine the prevalence of bacterial colonization of lesional skin and Staphylococcus aureus (S. aureus) in nares and perineum in 75 patients with DD, the association of these parameters with disease and patient characteristics, and the features of the bacterial skin infection in this group. Methods Medical interviews and physical examinations were performed. Bacteria were isolated from swabs taken from lesional skin, nares and perineum. Results S. aureus was isolated in 68%, 47% and 22% of lesional skin, nares and perineum cultures respectively. Subjects with positive S. aureus culture from lesional skin and/or nares had a statistically significant higher percentage of skin area affected and a more severe disease than patients with negative culture. Thirty of the 75 patients (40%) recalled bacterial skin infection, most often on the chest. Conclusions Patients with DD have high prevalence of S. aureus colonization in lesional skin and nares, with a correlation between disease severity and extent of the colonization. Further studies examining the consequences of S. aureus eradication in those sites may establish the need for S. aureus lesional skin and nares colonization screening and eradication as part of the treatment of DD exacerbations.     

Characteristics of Staphylococcus aureus colonization in patients with atopic dermatitis in Sri Lanka

Background. Colonization of the skin of patients with atopic dermatitis (AD) by Staphylococcus aureus (SA) is associated with more severe disease. Aim. To determine the association of SA colonization patterns and densities in lesional and nonlesional skin in patients with varying severities of AD, and to determine the antibiotic sensitivity patterns of SA isolates from Sri Lanka. Methods. Skin and nasal swabs collected from 100 patients with AD and 120 controls were used to investigate the presence of SA. Severity of AD was graded using the Nottingham Eczema Severity Score. Colony counts were obtained for skin samples, and antibiotic sensitivity testing was performed in cases positive for SA. Results. Skin colonization was seen in 57 patients (57%) but in only 10 controls (8%). Lesional skin of most patients (52/57; 91%) had SA densities of > 300 colony‐forming units/cm². Colonization rates with SA significantly increased with increasing age (Spearman correlation coefficient R = 0.9, P < 0.05) and increasing duration of lesions in patients with AD (Spearman R = 0.87, P < 0.05). Isolates from eight patients (13.5%) were found to be methicillin‐resistant S. aureus (MRSA). Only 6 isolates (10%) were susceptible to penicillin and 22 (37%) to erythromycin, while 28 (47%) isolates had erythromycin‐induced resistance to clindamycin. Conclusions. SA colonization rates were significantly associated with increasing age and severity of AD, and particularly with duration of lesions. Patients with severe disease were also more likely to be colonized with SA strains resistant to conventional antibiotics.     

Interleukin-18 is elevated in the horny layer in patients with atopic dermatitis and is associated with Staphylococcus aureus colonization

Background An increase in interleukin (IL)‐18 production from epidermal cells has been reported in an atopic dermatitis (AD) mouse model, and subsequent topical application of Staphylococcus aureus results in severe dermatitis. Objectives To reveal the relationship between S. aureus colonization of skin lesions and keratinocyte IL‐18 production, particularly in AD with relatively low serum IgE levels. We also aimed to establish a simple and noninvasive method of assaying IL‐18 produced by epidermal keratinocytes to evaluate local skin inflammation and therapeutic effects in patients with AD. Methods IL‐18 in the horny layer of the skin was collected via a tape‐stripping method and measured in 95 patients with AD and 40 healthy controls by enzyme‐linked immunosorbent assay (ELISA). Clinical severity, blood data and S. aureus skin colonization were evaluated before and after treatment. Results IL‐18 levels in the horny layer were significantly higher in the skin lesions of patients with AD than in healthy controls and correlated with SCORAD, levels of serum IL‐18, IgE, lactate dehydrogenase, thymus and activation‐regulated chemokine, blood eosinophils and transepidermal water loss. In the AD group with serum IgE < 1500 IU mL^?1, significantly higher IL‐18 levels were observed in the horny layer of patients colonized with S. aureus compared with those who were not. Conclusions Epidermal IL‐18 production was associated with the severity of AD. Staphylococcus aureus colonization seems to contribute to this IL‐18 production, especially in the AD group with relatively low IgE production. Tape stripping provides an easy and noninvasive method to assess epidermal IL‐18 production by ELISA.     

S. Aureus Isolation from the Lesions,the Hands,and the Anterior Nares of Patients with Atopic Dermatitis

Abstract: Staphylococcus aureus colonization is common in atopic dermatitis (AD) and can exacerbate the disease. Additionally, some evidence shows that patients with AD may act as reservoirs for S. aureus transmission to others. This study compared S. aureus colonization in AD patients and their caregivers with control patients and their caregivers. Quantitative cultures were obtained from the lesions, clinically normal skin, hands, and anterior nares of 100 patients with AD, 100 controls with other cutaneous disorders, and 200 caregivers. AD patients had a significantly greater carriage of S. aureus from lesional and clinically normal skin as well as the hand. Significant increases in carriage of S. aureus were found in the anterior nares and hands of caregivers of AD patients compared with control caregivers. Topical corticosteroid use did not affect recovery of S. aureus. There was a significant correlation between recovery of S. aureus from lesional skin and recovery from the anterior nares (p = .002) and hands (p < .0001). These findings suggest that the anterior nares and the hands may be important reservoirs and vectors for transmission of S. aureus to lesional skin and to close contacts of these patients.     

Comparative molecular analysis of meticillin‐resistant Staphylococcus aureus isolates from children with atopic dermatitis and healthy subjects in Taiwan

Background Children with atopic dermatitis (AD) are more frequently colonized by Staphylococcus aureus than healthy children. Objectives To assess whether any relationship exists between nasal meticillin‐resistant S. aureus (MRSA) colonization and subsequent skin and soft‐tissue infections (SSTI). Patients and methods From 2005 through 2006, comparative molecular analyses of 23 MRSA‐colonizing isolates from 133 children with AD, 44 MRSA‐colonizing isolates from 490 healthy controls, and 12 MRSA‐infecting isolates from 20 children with AD and concurrent SSTI were conducted. Results Nasal MRSA colonization in children with AD was significantly higher compared with normal individuals (17·3% vs. 9·0%; P = 0·01). The molecular characteristics differed significantly between the MRSA isolates from children with AD and the MRSA‐colonizing isolates from healthy controls. The clone characterized as sequence type (ST)59 (338)/pulsotype B/staphylococcal cassette chromosome mec (SCCmec) V_T/Panton–Valentine leucocidin (PVL)‐positive/staphylococcal enterotoxin B (SEB)‐positive accounted for half of the MRSA isolates from children with AD, and another clone, characterized as ST59/pulsotype A/SCCmec IV/PVL‐negative/SEB‐positive accounted for 61% of the MRSA‐colonizing isolates from healthy controls. Conclusions We found MRSA colonizing the anterior nares of a large number of Taiwanese children, especially among those with AD. Analysis of our data provides evidence that links MRSA‐colonizing isolates to MRSA‐infecting isolates from concurrent SSTI in children with AD.     

High genetic diversity of Staphylococcus aureus strains colonizing patients with epidermolysis bullosa

Patients with the blistering disease, epidermolysis bullosa (EB), frequently suffer from chronic wounds that become colonized by pathogenic bacteria, such as Staphylococcus aureus. To determine S. aureus colonization rates in patients with EB, swabs were collected from the anterior nares, throats and wounds of 52 Dutch patients with EB. Swabs were also collected from nares and throats of 13 healthcare workers who occasionally meet the sampled patients with EB. All EB patients with chronic wounds and 75% of the patients without chronic wounds were colonized with S. aureus. In contrast, 39% of the sampled healthcare workers were colonized with S. aureus. Typing revealed a high degree of genetic diversity of 184 collected S. aureus isolates. Autoinoculation of S. aureus in individual patients with EB was shown to occur frequently, whereas transmission of S. aureus between patients with EB is apparently rare. There was no evidence for S. aureus transmission between patients with EB and healthcare workers.     

MRSA eradication in dermatologic outpatients - theory and practice

Background: The dissemination of methicillin resistant staphylococcus aureus (MRSA) is an increasing challenge in medical care. Apart from hospital acquired MRSA, there has also been an increase in community acquired and livestock associated MRSA. While the risks of MRSA (e. g. wound infections) and consequences (e. g. rejection of patients) are well known, there are little data on the effectiveness of eradication procedures. Patients and methods: 32 patients with proven MRSA colonization were monitored during eradication for the following aspects: (1) localization of MRSA (swabs from hairline, anterior nares, throat, axillae, groins, perineum, and wounds, if present), (2) presence of eradication‐impairing factors, (3) length of time needed for eradication, (4) cost of eradication, (5) molecular fingerprint and risk assessment (spa‐types). Results: We describe the successful eradication of MRSA in all 32 patients. Most positive nasal swabs were obtained from the anterior nares and the throat and only rarely from the hairline or axillae. The greater the number of positive swabs, the more time was needed for eradication. In most patients (37.5%), eradication with topical antiseptics was successful. The average time for eradication was 12.97 (± 7.6) days. Twelve patients required systemic antibiotic therapy. Treatment costs associated with the use of systemic antibiotics were significantly higher. The most frequent spa types were t032 and t003. Conclusions: We report successful MRSA eradication in outpatients. Systemic antibiotics are unnecessary in the majority of patients. A combined anti‐MRSA strategy for inpatients and outpatients is recommended.     

Susceptibility testing and resistance phenotype detection in Staphylococcus aureus strains isolated from patients with atopic dermatitis, with apparent and recurrent skin colonization

Background Staphylococcus aureus colonization is accepted to be an important triggering factor in patients with atopic dermatitis (AD) and antibiotic resistance has been recognized to be a serious problem as a consequence and for the management of AD treatment. Objectives To investigate the antibiotic resistance pattern of S. aureus strains isolated from patients with AD with apparent (lesional and nonlesional skin areas) and recurrent skin colonization and strains obtained from healthy nasal carriers. Methods Eighty‐seven patients (age 23 ± 11·5 years) with mild to severe AD (SCORAD 46·9 ± 16·6), 21 patients (age 19·8 ± 6·7 years) before antistaphylococcal treatment and 177 healthy nasal carriers (age 27·5 ± 8·4 years) were microbiologically assessed for carriage of S. aureus. Colonization of lesional and nonlesional skin areas was quantified by counting the number of colony forming units on the skin surface (log₁₀ CFU cm^?2). Antimicrobial susceptibility and resistance phenotypes of 179 S. aureus strains were assessed with the agar disc‐diffusion method. Results Staphylococcus aureus was isolated from 87% of lesional and 44% of nonlesional skin samples from patients with AD. The colonization density of S. aureus was markedly higher in lesional than in nonlesional skin (P < 0·001), and was positively correlated with AD severity (P < 0·001) and total serum IgE (P < 0·05). Patients with AD had a significantly higher prevalence of chloramphenicol‐resistant S. aureus than nasal carriers (P < 0·01). Similar rates of resistance were expressed to tetracycline, erythromycin, mupirocin, clindamycin and penicillin. Nearly 35% of S. aureus strains from the lesional skin demonstrated different antimicrobial sensitivity pattern compared with strains from nonlesional skin of the same patients with AD. The trend of increasing resistance to chloramphenicol, erythromycin and fusidic acid was observed among S. aureus strains recovered from patients after approximately 75 days of antibiotic treatment. Methicillin‐resistant S. aureus isolates were cultured from two patients, one during exacerbation and the other after subsequent bacterial recolonization. Conclusions Discrepancies in antibiotic sensitivity pattern were observed among S. aureus strains colonizing different sites of AD skin (lesional and nonlesional areas), and also in AD patients with prior antibiotic treatment. Therefore, clinicians should consider repeat microbial susceptibility testing on different body sites of patients with AD when clinically indicated.     

Analysis of Colonization and Genotyping of the Exotoxins of Staphylococcus aureus in Patients with Atopic Dermatitis

Background

The skin of atopic dermatitis (AD) patients has a high susceptibility to Staphylococcus aureus colonization, and the toxins produced by S. aureus may aggravate AD by acting as superantigens.

Objective

The purpose of this study was to evaluate the relationship of the skin barrier function, colonization of S. aureus, and the clinical severity of AD. We also examined the predominant toxin genes produced in Korean AD patients.

Methods

Thirty-nine patients with AD were evaluated for clinical severity and skin barrier function by using Severity Scoring of Atopic Dermatitis (SCORAD) index and transepidermal water loss (TEWL). S. aureus was isolated from the forearm, popliteal fossa, and anterior nares of AD patients (n=39) and age-matched controls (n=40); the toxin genes were analyzed by performing multiplex polymerase chain reaction.

Results

TEWL showed a statistically significant correlation with clinical severity in patients with AD (p<0.05). TEWL was correlated with the number of S. aureus colonization sites and the presence of nasal colonization, but these results were not statistically significant. S. aureus strains were isolated in 64.1% of the 39 AD patients. The SCORAD index and AD severity were strongly correlated with the number of colonization sites. The predominant toxin gene found in AD patients was staphylococcal enterotoxin a (sea) only, which was produced in 52.6% of patients. The toxin genes sea and toxic shock syndrome toxin-1 (tsst-1) were found together in 42.1%, while tsst-1 only was found in 5.3% of the patients.

Conclusion

S. aureus strains were isolated in 64.1% of the 39 AD patients. Skin barrier function, as measured by TEWL, revealed a statistically significant correlation with clinical severity in AD patients. The SCORAD index and severity of AD was strongly correlated with the number of colonization. The most common toxin gene was sea in the Korean AD patients and this gene might have an important role in the pathogenesis of AD.     

Are there predominant strains and toxins of Staphylococcus aureus in atopic dermatitis patients? Genotypic characterization and toxin determination of S. aureus isolated in adolescent and adult patients with atopic dermatitis

The colonization of Staphylococcus aureus is one of the most important aggravating factors of atopic dermatitis (AD). Until now, the importance of S. aureus in AD and a positive correlation between colonization with S. aureus and clinical severity/skin barrier function has been demonstrated. The aim of this study was to determine whether there are certain clones of S. aureus which colonize the skin of AD patients. For this purpose, the genotype of S. aureus isolated from AD patients was examined by newly-developed typing methods. With 36 strains of S. aureus isolated from 35 patients with AD, spa typing, multi-locus sequence typing (MLST), and staphylococcal toxin gene assay by multiplex polymerase chain reaction, were performed. Clinical severity and skin barrier function were evaluated with eczema area and severity index (EASI) and with transepidermal water loss (TEWL). Among 36 strains of S. aureus , 14 sequence types (ST) and 20 spa types were identified, suggesting a very heterogeneous genetic composition of S. aureus and the absence of a prevailing genotype in S. aureus colonized with AD patients. Furthermore, there was no specific genotype of S. aureus which was associated with the clinical severity of AD or skin barrier dysfunction. A toxin gene assay, however, showed the predominance of S. aureus strains carrying sea and/or tsst-1 . To the best of our knowledge, this is the first report to show the genetic composition of S. aureus strains isolated from AD patients determined by sequence-based typing methods.     

Antibiotic treatment of cutaneous infections with Staphylococcus aureus in patients with atopic dermatitis: current antimicrobial resistances and susceptibilities

Background/aims: Atopic dermatitis (AD) is a common chronic inflammatory skin disease. In many patients, the disease is complicated by enhanced susceptibility to skin infections, especially with Staphylococcus aureus. The aim of this study was to determine the antimicrobial susceptibility of skin‐colonizing S. aureus strains in patients with AD and consecutively to recommend the first‐line antibiotic therapy. Methods: We studied S. aureus‐positive skin swabs (n = 102) from lesional skin of children, adolescents and adults with AD presenting to our inpatient and outpatient departments from January 2005 to June 2006. Results: Antimicrobial susceptibility testing revealed resistance against oxacillin, amoxicillin/clavulanic acid, cephalexin and cefuroxim in 3%, against tetracycline in 17%, against gentamicin in 16%, against erythromycin and clindamycin in 21%, against trimethoprim/sulfamethoxazol in 23%, against levofloxacin in 23%, against fusidic acid in 25%, against fosfomycin in 12% and against rifampicin in 16%. All strains isolated were susceptible to vancomycin. Conclusion: Currently, the first generation cephalosporin cephalexin appears to be the preferential first‐line antibiotic for the treatment of bacterial superinfections with S. aureus in children and adults with AD due to its restricted antimicrobial spectrum to Gram‐positive bacteria and a limited number of Gram‐negative strains. Cefuroxim and amoxicillin/clavulanate, which also showed 3% resistances in our patients, cover a broader range of bacterial micro‐organisms. However, a broader coverage is not required in case of AD, as S. aureus is the most frequent bacterial micro‐organism causing skin infections.     

Staphylococcus aureus Isolated from Nostril Anteriors and Subungual Spaces of the Hand: Comparative Study of Medical Staff,Patients, and Normal Controls

An epidemiologic investigation of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus (S. aureus) colonization was conducted at Kansai Medical University Hospital between 1990 and 1991. The incidence of nasal and subungual positivity for S. aureus was examined in a total of 156 subjects including inpatients, physicians, and nurses at a ward for dermatology, plastic surgery, and emergency patients, outpatients with atopic dermatitis and other skin diseases, and normal controls. Inpatients were most heavily colonized with MRSA (40.8%), but S. aureus colonization was most frequent in outpatients with atopic dermatitis (95.5%). Not only nostrils, which have been much discussed as a reservoir of S. aureus, but also subungual spaces seemed to be havens of S. aureus. Twelve out of 22 atopic dermatitis patients were positive for S. aureus on skin regions, and coagulase and phage testing showed a correlation between the nasal and skin-colonizing S. aureus. Coagulase type II and phase type NT (not typable) were the predominant types of S. aureus, including MRSA.     

Emergence of Multiresistant Methicillin‐Resistant Staphylococcus aureus in Two Patients with Atopic Dermatitis Requiring Linezolid Treatment

We report two patients with atopic dermatitis who developed methicillin‐resistant Staphylococcus aureus (MRSA) skin infections resistant to clindamycin and trimethoprim‐sulfamethoxazole requiring repeated linezolid treatment. For one patient and family members who received an aggressive regimen of staphylococcal decolonization, including intranasal mupirocin, dilute bleach baths, and bleach cleansing of household items and surfaces, subsequent culture results demonstrated methicillin‐susceptible S. aureus colonization and infection. These findings underscore the challenges presented by multiresistant MRSA infections in children with atopic dermatitis.     

Risks for Staphylococcus aureus colonization in patients with psoriasis: a systematic review and meta‐analysis

Evidence on whether patients with psoriasis have a higher risk for staphylococcal colonization than healthy controls remains controversial. To synthesize the current literature, we performed a systematic review on the prevalence and relative risk (RR) of Staphylococcus aureus colonization in patients with psoriasis. We modified the QUADAS‐2 instrument to assess the reporting quality of individual studies and applied random‐effects models in meta‐analysis. Overall we identified 21 eligible studies, of which 15 enrolled one or more comparison groups. The pooled prevalence of staphylococcal colonization in patients with psoriasis was 35·3% [95% confidence interval (CI) 25·0–45·6] on lesional skin and 39·2% (95% CI 33·7–44·8) in the nares. Patients with psoriasis were 4·5 times more likely to be colonized by S. aureus than healthy controls were on the skin (RR 5·54, 95% CI 3·21–9·57) and 60% more in the nares (RR 1·60, 95% CI 1·11–2·32). Cutaneous and nasal colonization by meticillin‐resistant S. aureus also appeared higher in patients with psoriasis (pooled prevalence 8·6%) than in healthy controls (2·6%), yet the difference was not statistically significant (P = 0·74). In contrast, despite of a similar risk for nasal staphylococcal colonization (RR 0·67, 95% CI 0·38–1·18), patients with psoriasis were less likely to carry S. aureus on lesional skin than atopic patients (RR 0·64, 95% CI 0·40–1·02). In summarizing the current literature, we found that patients with psoriasis were at an increased risk for staphylococcal colonization compared with healthy individuals. Prospective studies on how bacterial loads correlate with disease activity can guide the clinical management of bacterial colonization while preventing the emergence of drug‐resistant strains.     

Prevalence and molecular characteristics of Staphylococcus aureus isolates colonizing patients with atopic dermatitis and their close contacts in Singapore

Background  Staphylococcus aureus colonization is an established pathogenic factor for disease flare in atopic dermatitis (AD).
Objectives  We conducted a study to investigate the colonization of S. aureus in patients with AD and their close contacts in order to evaluate the possibility of intrafamilial transmission. We sought to determine the distribution of the bacterial virulence factors and their correlation with disease severity.
Methods  Nasal swabs and skin swabs (patients with AD only) were taken from patients with AD aged 2–21 years and their close contacts, seen at the National Skin Centre from January to March 2007. All S. aureus isolates were typed using multilocus variable-number tandem-repeat fingerprinting (MLVF) and screened for virulence factors via polymerase chain reaction (PCR) analysis. AD severity was determined by the SCORAD index.
Results  A total of 34 patients with AD and 55 close contacts were recruited. Thirty-one (91%) patients were colonized with S. aureus . Twenty-five (45%) of their close contacts were also colonized, and MLVF showed a high concordance of S. aureus isolates in index patients and their close contacts. On multivariate analysis, patients with a moderate SCORAD were more likely to be colonized by enterotoxin B-positive S. aureus ( P  = 0·027). No virulence factor was significantly associated with a severe SCORAD.
Conclusions  The prevalence of S. aureus colonization was high among patients with AD and their close contacts. However, no predominant isolate of S. aureus was found to be associated with AD. The presence of superantigen B is possibly associated with moderate rather than severe disease in our population.     

Antibiotic Susceptibility of Staphylococcus aureus in Atopic Dermatitis: Current Prevalence of Methicillin-Resistant Staphylococcus aureus in Korea and Treatment Strategies

Background

Staphylococcus aureus is a well-known microbe that colonizes or infects the skin in atopic dermatitis (AD). The prevalence of methicillin-resistant S. aureus (MRSA) in AD has recently been increasing.

Objective

This study aimed to determine the antimicrobial susceptibility patterns in AD skin lesions and evaluate the prevalence of MRSA in Korea. We also recommend proper first-line topical antibiotics for Korean patients with AD.

Methods

We studied S. aureus-positive skin swabs (n=583) from the lesional skin of infants, children, and adults who presented to our outpatient clinic with AD from July 2009 to April 2012.

Results

S. aureus exhibited high susceptibility against most antimicrobial agents. However, it exhibited less susceptibility to benzylpenicillin, erythromycin, clindamycin, and fusidic acid. The prevalence of MRSA was 12.9% among 583 S. aureus isolates, and the susceptibility to oxacillin was significantly lower in infants in both acute and chronic AD lesions.

Conclusion

S. aureus from AD has a high prevalence of MRSA and multidrug resistance, especially in infants. In addition, the rate of fusidic acid resistance is high among all age groups, and mupirocin resistance increases with age group regardless of lesional status. This is the first study comparing the antimicrobial susceptibility rates of S. aureus isolates from AD cases with respect to age and lesion status in Korea.     

Neonatal colonization with Staphylococcus aureus is not associated with development of atopic dermatitis

Background  Staphylococcus aureus in atopic skin has been associated with exacerbation of eczema.
Objectives  To investigate a possible association between neonatal colonization with S. aureus and the risk of atopic dermatitis (AD) during the first 3 years of life.
Materials and methods  The study participants were 356 children born of mothers with asthma from the Copenhagen Prospective Study on Asthma in Childhood. Swabs from the vestibulum nasi and the perineum were cultured at 1 month and 1 year, from acute eczema, and from parents (vestibulum nasi and pharynx). AD development and severity were monitored prospectively.
Results  Of the neonates, 5·3% had positive swabs for S. aureus cultured from the vestibulum nasi (51·3%) and/or the perineum (11·3%). Forty-two per cent developed AD, but without association between colonization with S. aureus at 1 month of age and risk of developing AD at 3 years of age. There was a 70% concordance for S. aureus carriage between neonates and parents. At 1 year of age 11·3% children had swabs positive for S. aureus . Fourteen per cent of children tested at the 1-year visit developed AD after the visit but before 3 years of age, but again, there was no association between colonization with S. aureus and the risk of AD. In children seen at acute visits the severity of AD measured by scoring of atopic dermatitis (SCORAD) was significantly higher in children with a positive culture for S. aureus in lesions.
Conclusions  Colonization with S. aureus at 1 month of age is not associated with an increased risk of developing AD during the first 3 years of life.     

Intrinsic alterations of pro-inflammatory mediators in unstimulated and TLR-2 stimulated keratinocytes from atopic dermatitis patients

Abstract: In many patients with atopic dermatitis (AD), the disease is complicated by their enhanced susceptibility to bacterial skin infections, especially with Staphylococcus aureus (S. aureus). Resistance to bacterial skin infections, e.g. S. aureus, is based on the function of intact innate immune mechanisms in the epidermis, mainly provided by keratinocytes. Toll‐like receptor (TLR)‐2 recognizes components of S. aureus and is known to be expressed on keratinocytes. The aim of this study was to investigate intrinsic TLR‐2 expression and cytokine secretion upon TLR‐2 stimulation with peptidoglycan (PGN), lipoteichoic acid (LTA) and N‐palmitoyl‐S‐[2,3‐bis(palmitoyl)‐(2RS)‐propyl]‐(R)cysteinyl‐alanyl‐glycine (Pam3Cys) in keratinocytes from patients with AD compared to healthy controls. Human primary keratinocytes (HPKs) were cultivated from hair follicles of patients with AD and non‐atopic healthy controls and stimulated with Pam3Cys, LTA and PGN. TLR‐2, TLR‐1 and TLR‐6 expression were investigated at the mRNA level. IL‐6, IL‐8, chemokine C‐C motif ligand (CCL)‐20 and MMP‐9 production were studied at the protein level. TLR‐2, TLR‐1 and TLR‐6 were expressed on both HPKs from patients with AD as well as healthy controls without significant differences between these groups. HPKs from patients with AD had an intrinsically reduced capacity to produce IL‐6, IL‐8, CCL‐20 and MMP‐9 and responded less to TLR‐2 stimulation compared to HPKs from healthy controls. Our findings show evidence for intrinsic alterations in HPKs from patients with AD compared to healthy controls and diminished responses upon TLR‐2 stimulation that might contribute to the enhanced susceptibility to skin infections with S. aureus.     

The complex biology and contribution of Staphylococcus aureus in atopic dermatitis,current and future therapies

Atopic dermatitis (AD) is a complex, chronic inflammatory skin disorder affecting more than 10% of U.K. children and is a major cause of occupation‐related disability. A subset of patients, particularly those with severe AD, are persistently colonized with Staphylococcus aureus and exacerbation of disease is commonly associated with this bacterium by virtue of increased inflammation and allergic sensitization, aggravated by skin barrier defects. Understanding the complex biology of S. aureus is an important factor when developing new drugs to combat infection. Staphylococcus aureus generates exoproteins that enable invasion and dissemination within the host skin but can also damage the skin and activate the host immune system. Antibiotics are often used by dermatologists to aid clearance of S. aureus; however, these are becoming less effective and chronic usage is discouraged with the emergence of multiple antibiotic‐resistant strains. New ways to target S. aureus using monoclonal antibodies and vaccines are now being developed. This review will attempt to evaluate the key biology of S. aureus, current treatment of S. aureus infections in AD and recent advances in developing new anti‐S. aureus therapies that have potential in severe AD.