<b><i>Background:</i></b> Atopic dermatitis is a chronic inflammatory dermatosis with complex pathogenesis. The skin microbiome in atopic dermatitis is dominated by <i>Staphylococcus aureus</i> which shows the ability to produce biofilm. <b><i>Objectives:</i></b> The aim of this work was to assess the influence of <i>S. aureus</i> biofilm on the course of atopic dermatitis. <b><i>Methods:</i></b> Disease severity was evaluated based on the SCORAD index in 56 adult patients with atopic dermatitis. Microtiter plate assay of the propensity to form biofilm was performed on <i>S. aureus</i> strains isolated from the anterior nares, lesional skin, and nonlesional skin. Microbiological results were correlated to the clinical parameters and total IgE concentration. <b><i>Results:</i></b> Biofilm-producing strains of <i>S. aureus</i> were identified in 76.3% (29/38) and 79.1% (34/43) of samples from the anterior nares and lesional skin, respectively (<i>p</i> &#x3e; 0.05), and in 48.5% (16/33) of samples from nonlesional skin (<i>p</i> &#x3c; 0.03). Patients colonized by biofilm-producing strains of <i>S. aureus</i> within the anterior nares showed statistically higher mean values of total and objective SCORAD and its components (extent, dryness), and of the largest extent of skin lesions during the flares in the last year when compared to patients colonized by non-biofilm-producing strains. Carriage of biofilm-producing <i>S. aureus</i> on lesional skin was associated with higher mean values of the extent of skin lesions during stable periods of the disease. <b><i>Conclusions:</i></b> The results of this study may suggest a relationship between the production of biofilm by <i>S. aureus</i> strains colonizing the anterior nares and the course of atopic dermatitis. Biofilm seems crucial for dispersal and persistent colonization of large areas of the skin by this pathogen. Destruction of <i>S. aureus</i> biofilm could positively affect the course of atopic dermatitis.

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Staphylococcus aureus superantigens (SAgs) have been reported to aggravate atopic dermatitis. However, comprehensive analyses of these molecules in multiple microniches are lacking. The present study involved 50 adult patients with active atopic dermatitis. S. aureus was isolated from the lesional skin, nonlesional skin, and anterior nares. Multiplex-PCR was performed to identify genes encoding (1) selX (core genome); (2) seg, selI, selM, selN, selO, selU (enterotoxin gene cluster, EGC); and (3) sea, seb, sec, sed, see, tstH (classic SAgs encoded on other mobile genetic elements). The results were correlated to clinical parameters of the study group. selx and EGC were the most prevalent in all microniches. The number of SAg-encoding genes correlated between the anterior nares and nonlesional skin, and between the nonlesional and lesional skin. On lesional skin, the total number of SAg genes correlated with disease severity (total and objective SCORAD, intensity, erythema, edema/papulation, lichenification and dryness). Linear regression revealed that AD severity was predicted only by selx and EGC. This study revealed that selX and EGC are associated with atopic dermatitis severity. Anterior nares and nonlesional skin could be reservoirs of SAg-positive S. aureus. Restoring the physiological microbiome could reduce the SAg burden and alleviate syndromes of atopic dermatitis.

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IntroductionPositive skin prick tests (SPT) results with protein allergens are the minor Hanifin and Rajka’s atopic dermatitis (AD) criterion. In adults, they mainly concern aeroallergens. The inflammation of skin often prevents SPT, but does not exclude the assessment of serous specific immunoglobulin E (sIgE) concentrations.AimTo assess usefulness of testing AD patients to aeroallergens with SPT and sIgE concentrations, and the correlation of these results and the clinical AD course.Material and methodsIn 286 AD patients, total IgE and sIgE (14 aeroallergens) were measured. SPTs were performed with 17 aeroallergens. The AD severity was determined depending on the concurrent co-existence of asthma, allergic rhinitis, extensive skin flares and severe itching.Results59.1% and 66.1% of patients have had positive results of sIgE and SPT, respectively (p > 0.05). The concentration of total IgE has positively correlated with the number of positive sIgE results (rho = 0.588, p < 0.001) and their intensity (rho = 0.592, p < 0.001). Among the patients with at least one high positive sIgE score, severe AD patients have been dominant (59.8% vs. 40.2%, p < 0.04). Among the patients with positive results without any high scores, the percentages are 21.6 and 78.4, respectively (p < 0.001).ConclusionsThe compatibility of SPT results and IgE concentrations indicates that the two methods equally assess aeroallergy in AD patients. The assessment of sIgE concentrations is especially advisable in patients with an elevated total IgE level. The obtained results may suggest that presence of a high specific IgE level of antibodies to aeroallergens may be the factor predicting a severe clinical AD course.