Skin colonization by Staphylococcus aureus in patients with eczema and atopic dermatitis and relevant combined topical therapy: a double-blind multicentre randomized controlled trial

BACKGROUND: Staphylococcus aureus has a peculiar ability to colonize the skin of patients with eczema and atopic dermatitis (AD), and is consistently found in eczematous skin lesions in these patients. A correlation between the severity of the eczema and colonization with S. aureus has been demonstrated, and it has been determined that bacterial colonization is an important factor aggravating skin lesions. Patients colonized with S. aureus have been treated with antibiotics in several open and double-blind placebo-controlled studies, with conflicting results. OBJECTIVES: To investigate the colonizing features of S. aureus in the lesional and nonlesional skin of patients with eczema and AD in China and to compare the therapeutic effect of mupirocin plus hydrocortisone butyrate with vehicle ointment plus hydrocortisone butyrate. METHODS: A multicentre, double-blind randomized trial was conducted. Eczema Area and Severity Index (EASI) scores were evaluated before the start of the trial and on the 7th, 14th and 28th day of treatment. Swabs for bacterial isolation were taken from lesional skin before the start of the trial and on the 7th, 14th and 28th day of treatment, and from nonlesional skin only before the start of the trial. A combination topical therapy with mupirocin plus hydrocortisone butyrate ointment was used in the experimental group, with vehicle ointment plus hydrocortisone butyrate ointment as a control. RESULTS: Of 327 patients enrolled in the study, 208 had eczema and 119 had AD. Bacteria were isolated from 70.2% of lesional and 32.7% of nonlesional skin samples from patients with eczema, of which S. aureus accounted for 47.3% and 27.9%, respectively. Bacteria were isolated from 74.8% of lesional and 34.5% of nonlesional skin samples from patients with AD, of which S. aureus accounted for 79.8% and 80.5%, respectively. The colonization density of S. aureus was markedly higher in lesional than in nonlesional skin, both in patients with eczema and with AD (P < 0.01, P < 0.05), and was positively correlated with lesion severity. Considering the EASI scores before and after treatment and the final effective rate, good therapeutic effects were obtained in both the combination experimental groups and the control groups (P < 0.01), and there were no differences in the global therapeutic effect between the two groups in patients with eczema and with AD (P > 0.05). However, in patients with eczema with a clinical score of > 8 or in patients with AD with a clinical score of > 7, the therapeutic effect in the experimental groups was superior to that in the control groups (P < 0.05) on the 7th day of treatment. There were no differences between the two groups on the 14th and 28th days of treatment (P > 0.05). Following the improvement of symptoms and signs of eczema and AD, the positive rates of bacteria and S. aureus were reduced on the 7th day of treatment. CONCLUSIONS: This study confirmed that lesional skin of patients with eczema and AD was more frequently colonized with S. aureus than was nonlesional skin. The more severe the eczema, the higher the colonization rate of S. aureus, and S. aureus was also more often present in lesional and nonlesional skin in patients with AD than in those with eczema. Staphylococcus aureus infection is related to the pathogenesis of eczema and AD. An antibiotic-corticosteroid combination and corticosteroid alone both gave good therapeutic effect in eczema and in AD, and both reduced colonization by S. aureus. Early combined topical therapy is beneficial to patients with moderate to severe eczema and AD, and it is unnecessary to use antibiotics at later stages of disease or in mild eczema or AD.     

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.     

Microanalysis of an antimicrobial peptide, beta-defensin-2, in the stratum corneum from patients with atopic dermatitis

Background  Antimicrobial peptides, such as defensin and cathelicidin, have recently been reported to play important roles in host defence and in cutaneous innate immunity. Although β-defensin-2 has been reported to be downregulated in the skin of patients with atopic dermatitis (AD), little is known about its role in the colonization of Staphylococcus aureus in the stratum corneum of patients with AD. A precise evaluation of these peptides in the stratum corneum as an antimicrobial barrier against S. aureus colonization has not yet been performed.
Objectives  To compare β-defensin-2 levels in the skin of patients with AD and healthy controls.
Methods  We developed a microanalytical technique to measure β-defensin-2 in the stratum corneum using a combination of immunoprecipitation and Western blotting.
Results  β-Defensin-2 in the stratum corneum was significantly higher in AD lesional skin compared with healthy control skin. The β-defensin-2 content in AD lesional skin also increased in proportion to the severity of the disease. Counting bacterial colonies revealed higher populations of S. aureus on lesional and nonlesional skin surfaces of patients with AD compared with healthy controls. Comparison of S. aureus colony numbers and β-defensin-2 levels demonstrated a positive correlation ( r  =   0·342, P  =   0·004, n  =   67) between both factors.
Conclusions  Collectively, these findings suggest that β-defensin-2 is induced in response to bacteria, injury or inflammatory stimuli and is not associated with vulnerability to S. aureus colonization in the skin of patients with AD.     

特应性皮炎皮损金黄色葡萄球菌检出情况的研究

目的 :　探讨特应性皮炎 (AD)皮损微生物定植情况 ,为临床合理选用抗菌药物有效控制该病提供依据。方法 :　无菌生理盐水浸湿的棉拭子于 4 3例AD患者皮损处取标本 ,同时对 39例患者非皮损处及 10例健康人取标本作对照 ,进行细菌培养及菌落计数 ,金葡菌予常规药敏试验。结果 :　AD患者皮损细菌阳性率为 74 .4 2 % ,金葡菌为主要的致病菌 ,占 6 5 .6 3% ;非皮损处也可分离出细菌 ,但金葡菌阳性率及密度均明显低于皮损处 (P <0 .0 0 1)。结论 :　微生物感染因素 ,尤其金葡菌感染或定植 ,在AD的发病中起着重要的作用     

Staphylococcus aureus in Atopic Dermatitis and in Nonatopic Dermatitis

Skin colonization with Staphylococcus aureus (S. aureus) was examined in 30 patients with atopic dermatitis (AD), in 25 patients with nonatopic eczema (NAE) and in 30 individuals as healthy controls (HC). Bacteria growth was examined in aerobic cultures and the population densities per dish were estimated; S. aureus colonization was found in the eczematous skin of 24 of 30 (80%) AD patients and in 13 of 25 (52%) NAE patients (NS, p greater than 0.1). In nonaffected skin S. aureus colonization was found in 19 of 30 (63%) of all AD patients compared with 6 of 25 (24%) in NAE patients and 1 of 30 (3%) in HC, respectively (p less than 0.05). In nonaffected skin, coagulase negative strains of staphylococcus were found in 25 of 30 (84%) controls and in 18 of 25 (72%) NAE patients compared with 12 of 30 (40%) patients with AD. It seems that colonization with S. aureus is not a characteristic feature for atopic dermatitis but is a frequent event in damaged skin; significantly elevated values were also observed in nonatopic eczema. The degree of colonization may depend on the severity and duration of the eczematous lesions.     

Staphylococcus aureus skin colonization in atopic dermatitis patients

A study was conducted to compare the Staphylococcus aureus skin colonization of 21 patients with atopic dermatitis (AD) and 22 healthy controls. It was found that the total aerobe count (total CFU/cm2), the S. aureus fraction thereof and the S. aureus carrier frequency were significantly higher in apparently normal skin of AD patients than in healthy individuals. In addition, compared to normal skin of patients S. aureus density was 100 to 1,000 times higher in the 3 different kinds of lesional skin (dermatitic, lichenified and impetiginized sites). 190 S. aureus strains isolated from the skin of AD patients were tested for sensitivity to 5 topically used antibiotics and the results reported. Besides the biological consequences for the person affected by AD this severe colonization with S. aureus is of epidemiological importance. Several outbreaks of S. aureus infections by dispersal from dermatitic skin have been described. Therefore some preventive and therapeutic aspects are discussed.     

Immune response to Staphylococcus aureus in atopic dermatitis

The skin of patients with atopic dermatitis (AD) is severely colonized with Staphylococcus aureus. Therefore, a study was conducted to assess some basic features of the S. aureus-specific immune response in patients with AD and healthy nonatopic individuals. Some particular features were found: a selective hyporesponsiveness to purified S. aureus cell walls (PCW) in delayed skin reactivity; half of our AD patients showed serum IgE to PCW and soluble S. aureus protoplast antigens; elevated PCW-IgE did not correlate with positive immediate skin reactions to whole S. aureus and their cell walls; regional lymphadenopathy but not impetiginization was associated with increased PCW-IgE and high total IgE. It is suggested that these changes in the immune response to S. aureus are related to the chronic S. aureus colonization of the skin.     

Isolation of α-toxin-producing Staphylococcus aureus from the skin of highly sensitized adult patients with severe atopic dermatitis

Background  Staphylococcus aureus (S. aureus) is a well-known trigger factor of atopic dermatitis (AD). Besides staphylococcal superantigens, α-toxin may influence cutaneous inflammation via induction of T-cell proliferation and cytokine secretion.
Objectives  To investigate the association between sensitization to inhalant allergens and skin colonization with α-toxin-producing S. aureus in AD.
Patients and methods  We investigated 127 patients with AD, aged 14–65 years, who were on standard anti-inflammatory and antiseptic treatment before investigation. We evaluated skin colonization, medical history, severity of AD and sensitization to inhalant allergens.
Results  Forty-eight of 127 patients were colonized with S. aureus , suffered from more severe AD, had asthma more often and showed higher sensitization levels to inhalant allergens. Thirty of 48 patients with S. aureus skin-colonizing strains produced α-toxin and had higher total IgE and specific IgE to birch pollen and timothy grass pollen.
Conclusions  Under topical treatment with antiseptic and anti-inflammatory agents the colonization of lesional skin with S. aureus was clearly lower than commonly found in untreated patients with AD. Colonization with S. aureus was associated with a higher severity of AD, higher degree of sensitization, and a higher frequency of asthma. The proportion of patients whose skin was colonized with α-toxin-producing S. aureus was higher than expected from a former study. Cutaneous colonization with α-toxin-producing S. aureus was associated with a higher sensitization level to birch pollen allergen in AD. This may point to a higher susceptibility of patients with higher T-helper 2 polarization towards α-toxin-producing S. aureus .     

Decreased levels of sphingosine,a natural antimicrobial agent,may be associated with vulnerability of the stratum corneum from patients with atopic dermatitis to colonization by Staphylococcus aureus

The stratum corneum of the skin of patients with atopic dermatitis is highly susceptible to colonization by various bacteria, including Staphylococcus aureus. The defense system of the skin against bacterial invasion appears to be significantly disrupted in atopic dermatitis skin, but little is known about the defense mechanism(s) involved. As one sphingolipid metabolite, sphingosine is known to exert a potent antimicrobial effect on S. aureus at physiologic levels, and it may play a significant role in bacterial defense mechanisms of healthy normal skin. Because of the altered ceramide metabolism in atopic dermatitis, the possible alteration of sphingosine metabolism might be associated with the acquired vulnerability to colonization by S. aureus in patients with atopic dermatitis. In this study, we measured the levels of sphingosine in the upper stratum corneum from patients with atopic dermatitis, and then compared that with the colonization levels of bacteria in the same subjects. Levels of sphingosine were significantly downregulated in uninvolved and in involved stratum corneum of patients with atopic dermatitis compared with healthy controls. This decreased level of sphingosine was relevant to the increased numbers of bacteria including S. aureus present in the upper stratum corneum from the same subjects. This suggests the possibility that the increased colonization of bacteria found in patients with atopic dermatitis may result from a deficiency of sphingosine as a natural antimicrobial agent. As for the mechanism involved in the decreased production of sphingosine in atopic dermatitis, analysis of the activities of ceramidases, major sphingosine-producing enzymes, revealed that, whereas the activity of alkaline ceramidase did not differ between patients with atopic dermatitis and healthy controls, the activity of acid ceramidase was significantly reduced in patients with atopic dermatitis and this had obvious relevance to the increased colonization of bacteria in those subjects. Further, there was a close correlation between the level of sphingosines and acid ceramidase (r = 0.65, p < 0.01) or ceramides (r = 0.70, p < 0.01) in the upper stratum corneum from the same patients with atopic dermatitis. Collectively, our results suggest the possibility that vulnerability to bacterial colonization in the skin of patients with atopic dermatitis is associated with reduced levels of a natural antimicrobial agent, sphingosine, which results from decreased levels of ceramides as a substrate and from diminished activities of its metabolic enzyme, acid ceramidase.     

Persistence of Staphylococcus aureus colonization on the skin of NC/Nga mice

BACKGROUND: Colonization of Staphylococcus aureus (S. aureus) on skin is one factor which can worsen atopic dermatitis (AD). The reduction of bacterial colonization in these lesions was reported to be effective for the treatment of subjects with AD. NC/Nga mice are recognized to be a model of AD. OBJECTIVE: We examined the susceptibility of S. aureus colonization on the skin in NC/Nga mice, as compared with findings in BALB/c mice. METHODS: The number of S. aureus on the skin was counted and serum corticosterone, serum interferon-gamma (IFN-gamma) and interleukin (IL)-12 levels were measured. The effects of dexamethasone on number of S. aureus on the skin and serum IFN-gamma and interleukin IL-12 levels were also examined. RESULTS: The number of S. aureus increased in parallel with the severity of the dermatitis in these mice, and the remaining number of S. aureus on the skin after topical treatment of S. aureus suspension was higher than that in BALB/c mice. Serum IFN-gamma and IL-12 concentrations in NC/Nga mice were lower than in BALB/c mice, and the circadian variations of serum corticosterone concentrations in NC/Nga mice tended to reveal higher levels compared with the circadian variations in BALB/c mice. Continuous administration of dexamethasone inhibited the elimination of S. aureus from skin surfaces of BALB/c mice. Serum IFN-gamma and IL-12 concentrations in dexamethasone-treated BALB/c mice were lower than those in vehicle-treated BALB/c mice. CONCLUSION: Our data support the notion that high levels of circadian variations of endogenous glucocorticoid lead to a lack of protection against bacteria and a persistence of S. aureus colonization on the skin in NC/Nga mice.     

特应性皮炎患儿皮损局部金黄色葡萄球菌外毒素检测

目的 了解特应性皮炎(AD)患儿皮损局部金黄色葡萄球菌(金葡菌)的带菌率及其分泌外毒素的情况,探讨金葡菌及其分泌的外毒素在AD发病中的作用.方法 AD皮损局部分离金葡菌,反向被动乳胶试验方法检测其外毒素表达,并与对照组进行统计学比较.结果 与对照组相比,AD患儿无论是皮损局部还是非皮损区金葡菌带菌率明显升高(P值均<0.01),且与疾病严重性呈正相关性(P<0.01).但AD皮损局部的金葡菌与对照组金葡菌相比,两者分泌外毒素的情况差异无显著性(P>0.05),并且皮损局部的金葡菌是否分泌外毒素与疾病严重性无直接相关性(P>0.05),但伴有血清总IgE水平升高的AD患儿,疾病相对较重(P<0.01).结论 AD患儿皮损区金葡菌带菌率为43.24%,其中47.46%分泌外毒素,以金葡菌肠毒素B(SEB)最常见.     

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.     

Seemingly healthy skin in atopic dermatitis: observations with the use of high‐frequency ultrasonography,preliminary study

Background: Atopic dermatitis (AD) is a chronic, relapsing skin disorder which is strictly determined by the epidermal barrier function. In previous studies, there is conclusive evidence that normal‐looking, nonlesional skin presents meaningful barrier function defect and a sub‐clinical eczematous skin reaction. Aim: The authors intended to visualize nonlesional AD skin with the use of high frequency ultrasonography to show that the normal‐looking, nonlesional skin may present significant abnormalities in USG examination. Methods: We have performed analysis with the use of high‐frequency 20 MHz skin sonography in the cases of 15 AD patients of the Department of Dermatology, Medical University, Poznań, Poland. The clinical score has been evaluated on the basis of W‐AZS index and EASI. The results were presented in the form of ultrasonographic images. Results: High frequency ultrasonography revealed an echopoor band within nonlesional skin of six (40%) examined AD patients and in all cases within skin lesions. Conclusion: Our results indicate the significant role of skin ultrasonography in the complete clinical evaluation of patients with AD, which may serve as an element in selection of the most appropriate topical treatment. An echopoor band beneath the echo entry within nonlesional skin of some AD patients may reflect subclinical eczematous reaction and the readiness for the development of typical skin lesions. For this purpose, we suggest to name an intact skin in AD as seemingly healthy skin.     

早婴儿特应性皮炎发病因素探讨

目的观察纯母乳喂养特应性皮炎(atop ic derm atitis,AD)患儿皮损金黄色葡萄球菌(金葡菌)带菌率,与黄疸的相关性及乳母饮食对AD的影响,探讨以上因素在AD发病中的作用。方法AD皮损局部、非皮损局部分离金葡菌、经皮测定黄疸指数、乳母饮食随机分组,并与对照组进行统计学比较。结果与对照组相比,AD患儿皮损局部金葡菌与对照组金葡菌相比明显升高,黄疸与AD的发病无统计学意义,乳母饮食与AD有关。结论AD患儿皮损区带菌率45.00%,黄疸与AD的发病无相关性,乳母饮食情况参与AD发病。     

Repetitive scratching and noxious heat do not inhibit histamine-induced itch in atopic dermatitis

BACKGROUND: Repetitive scratching is the most common behavioural response to itch in atopic dermatitis (AD). Patients with chronic itch often report that very hot showers inhibit itch. We recently reported that scratching and noxious heat stimuli inhibit histamine-induced itch in healthy subjects. However, no psychophysical studies have been performed in AD to assess the effects of repetitive heat pain stimuli and scratching on histamine-induced itch. OBJECTIVES: To examine the effects of repetitive noxious heat and scratching on itch intensity in patients with AD using quantitative sensory testing devices. METHODS: Itch was induced with histamine iontophoresis in 16 patients with AD in both lesional and nonlesional skin as well as in 10 healthy subjects. Repetitive noxious heat and scratching were applied 3 cm distal to the area of histamine iontophoresis. Subjects rated their perceived intensity of histamine-induced itch with a computerized visual analogue scale. RESULTS: Our results demonstrate that repetitive noxious heat and scratching do not inhibit itch intensity in lesional and nonlesional AD skin but do so in healthy skin. Of note, both these stimuli increase itch intensity in lesional AD skin. CONCLUSIONS: Our results strongly suggest that scratching and noxious thermal stimuli have a different effect upon histamine-induced itch perception in patients with AD when compared with healthy controls. This difference may be associated with both peripheral and central sensitization of nerve fibres in AD.     

Staphylococcus aureus: colonizing features and influence of an antibacterial treatment in adults with atopic dermatitis

BACKGROUND: The skin of up to 100% of patients with atopic dermatitis (AD) is colonized with Staphylococcus aureus. Of all S. aureus strains isolated from lesional skin, up to 65% have been shown to produce exotoxins with superantigenic properties. Patients colonized with S. aureus have been treated with antibiotics in several open and double-blind placebo-controlled studies, with conflicting results. These studies did not consider the anterior nares as a reservoir of S. aureus, or the possibility of transmission between patients and their contacts. Moreover, adult patients have not so far been investigated. OBJECTIVES: To investigate the colonizing features of S. aureus in adults with AD and in their contacts, and the effect of an antimicrobial treatment of the patients and their partners. METHODS: Swabs were taken from the skin and anterior nares of 66 adults with AD. S. aureus strains were screened for the production of exotoxins in 32 patients. Ten patients (two with toxigenic strains, eight with non-toxigenic strains) were treated orally with cefalexin, chlorhexidine ointment was applied to the skin, and the anterior nares were treated with mupirocin ointment. A bath containing potassium permanganate was taken daily. In addition, their partners were treated topically. RESULTS: Sixty-two of 66 patients (94%) were carriers of S. aureus, and mostly harboured the bacteria on both skin and anterior nares. Ten of 32 (31%) patients were colonized with toxigenic strains. The Severity Scoring in AD (SCORAD) score decreased in nine of 10 patients who received antimicrobial treatment (P < 0.001), and this effect was more pronounced in patients with a baseline SCORAD > 50. CONCLUSIONS: S. aureus may play an important role as an aggravating factor in adults with AD, as antimicrobial treatment leads to a significant improvement of AD in patients who are colonized with the bacterium.     

High-expression of sphingomyelin deacylase is an important determinant of ceramide deficiency leading to barrier disruption in atopic dermatitis

We have previously demonstrated that there is abnormal expression of sphingomyelin (SM) deacylase-like enzyme in the epidermis of patients with atopic dermatitis (AD), which results in decreased levels of ceramides in their involved and uninvolved stratum corneum. For quantitation of the expression of SM deacylase in AD, we synthesized 16-(9-anthroyloxy) hexadecanoylsphingosylphosphorylcholine or [palmitic acid-14C] SM and used them as substrates to directly measure the activity of SM deacylase by detecting the release of labeled free fatty acid. Direct enzymatic measurements demonstrated that stratum corneum from lesional forearm skin (volar side) of AD patients has an extremely high SM deacylase activity that is at least five times higher than in the stratum corneum from healthy controls. In stratum corneum from nonlesional skin of AD patients, SM deacylase activity is still at least three times higher than in healthy controls. In contrast, stratum corneum from contact dermatitis patients shows levels of SM deacylase similar to healthy controls. In extracts of whole epidermis biopsies from AD patients, SM deacylase activities are significantly (3-fold) increased over healthy controls in the particulate fraction, whereas there is no significant difference in the activity of sphingomyelinase between AD and healthy control. In peripheral blood lymphocytes of AD patients, there is no increase in activity compared with healthy controls, indicating a possibility that the high expression of SM deacylase is highly associated with the skin of AD patients. These findings suggest that, in contrast to changes in sphingolipid metabolism due to aging, the hitherto undiscovered enzyme SM deacylase, is highly expressed in the epidermis of AD patients, and competes with sphingomyelinase or beta-glucocerebrosidase for the common substrate SM or glucosylceramide, which leads to the ceramide deficiency of the stratum corneum in AD.     

T cells and mast cells as a major source of interleukin-13 in atopic dermatitis

BACKGROUND: Interleukin (IL)-13 is a T-cell-derived cytokine that shares several functions with IL-4, including the induction of immunoglobulin E synthesis. Recent studies suggest that cytokines expressed locally in the skin play several critical roles in atopic dermatitis (AD), however, little is known about the role of IL-13 in AD lesions. OBJECTIVES: The present study was designed to characterize the involvement of IL-13 in AD in the skin and peripheral blood mononuclear cells (PBMC). METHODS: Using lesional and nonlesional skin from adult AD patients and normal skin from healthy volunteers, we performed RT-PCR, in situ RT and immunostaining to determine the IL-13 expression at the mRNA and protein levels. The actual numbers of IL-13 expressing cells in biopsy specimens were counted under the microscope. IL-13 mRNA expression in PBMC from AD patients and healthy volunteers was examined by RT-PCR analysis. RESULTS: IL-13 mRNA expression was detected by RT-PCR in lesional and nonlesional skin and in PBMC from AD patients, but not in normal skin or PBMC from healthy volunteers. In AD lesional skin, numerous IL-13 mRNA-positive cells were demonstrated by in situ RT, and similar numbers of IL-13-positive cells were also detected immunohistochemically. Smaller numbers of IL-13-positive cells were observed in AD nonlesional skin and in normal skin. The differences in the numbers of IL-13-expressing cells between lesional and nonlesional skin were statistically significant. Double immunostaining revealed that IL-13 was produced in approximately 40% of T cells and 20% of mast cells in AD lesional skin, suggesting that T cells and mast cells are major sources of IL-13 in AD lesions. CONCLUSION: IL-13 may play a local as well as a systemic role in the development of AD lesions.     

Staphylococcus aureus re-colonization in atopic dermatitis: beyond the skin

Patients with atopic dermatitis (AD) are often heavily colonized by Staphylococcus aureus, which adversely affects eczema severity. Strategies to control S. aureus in AD include antibiotic and or antiseptics. However long-term efficacy is unclear. In this study we consider extra-cutaneous factors that may cause S. aureus re-colonization in adult AD. Twenty-one patients with AD were recruited and were assessed for: duration of AD, use of topical or oral antibiotic within the preceding 3 months, the number of hospital admissions during the preceding year and current treatment. The types of topical treatments used, vehicle, container and the expiry dates were also recorded. The severity of AD was assessed by SCORAD index. Microbiological assessment for S. aureus carriage from affected skin, anterior nares, emollient and topical steroid was undertaken using culture, Staphaurex test and antibiotic resistance. Of the patients 86% had S. aureus colonization. The median SCORAD score were greater in those colonized with S. aureus (P = 0.02) and those with contaminated treatments (P = 0.05). Prior antibiotic treatment, prior hospital admission and nasal carriage did not influence the median SCORAD. Three extra-cutaneous mechanisms by which S. aureus can re-colonize the skin were identified: antibiotic resistance, nasal carriage and treatment contamination.     

湿疹与特应性皮炎皮损处细菌学研究

目的 探讨湿疹和特应性皮炎(AD)皮损处的细菌学特点及金黄色葡萄球菌(金葡菌)在湿疹及AD发病中的作用。方法 多中心随机双盲对207例湿疹患者和119例AD患者皮损及非皮损处取材做细菌培养,并对所分离到的金葡菌进行常规药敏试验和噬菌体分型。结果 207例湿疹患者皮损处的细菌检出阳性率、金葡菌的比例及定植均明显高于非皮损处,差异有显著性(P<0.01)。119例AD患者皮损处的细菌检出阳性率及金葡菌的定植明显高于非皮损处,差异有显著性。对分离到的141株金葡菌进行噬菌体分型。Ⅰ组占6.3%,Ⅱ组占7.0%,Ⅲ组占3.5%,Ⅴ组占0.7%,杂组占1.4%,不能分型占56%,MRSA分型噬菌体26株混合组占6.3%。药敏试验结果表明在常用的6种外用抗菌药物中莫匹罗星对金葡菌和表皮葡萄球菌的抗菌活性最强,其MIC范围、MIC₉₀和MIC₅₀是6种抗菌药物中最低的。且莫匹罗星对金葡菌及其中的各噬菌体分型和表皮葡萄球菌中的耐甲氧西林和耐甲氧西林凝固酶阴性菌株也有较好的抑菌能力。结论 湿疹和AD的发病与细菌感染密切相关,其中金葡菌是最重要的细菌,对湿疹和AD患者外用药治疗合并使用外用抗菌药物是必要的,根据对金葡菌抗菌活性的测定,莫匹罗星的效果较好。