Supplementary Material for: The Propensity to Form Biofilm in vitro by Staphylococcus aureus Strains Isolated from the Anterior Nares of Patients with Atopic Dermatitis: Clinical Associations

Background: Atopic dermatitis is a chronic inflammatory dermatosis with complex pathogenesis. The skin microbiome in atopic dermatitis is dominated by Staphylococcus aureus which shows the ability to produce biofilm. Objectives: The aim of this work was to assess the influence of S. aureus biofilm on the course of atopic dermatitis. Methods: 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 S. aureus strains isolated from the anterior nares, lesional skin, and nonlesional skin. Microbiological results were correlated to the clinical parameters and total IgE concentration. Results: Biofilm-producing strains of S. aureus were identified in 76.3% (29/38) and 79.1% (34/43) of samples from the anterior nares and lesional skin, respectively (p > 0.05), and in 48.5% (16/33) of samples from nonlesional skin (p S. aureus 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 S. aureus on lesional skin was associated with higher mean values of the extent of skin lesions during stable periods of the disease. Conclusions: The results of this study may suggest a relationship between the production of biofilm by S. aureus 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 S. aureus biofilm could positively affect the course of atopic dermatitis.

背景：特应性皮炎（Atopic dermatitis）是一种发病机制复杂的慢性炎症性皮肤病，其皮肤微生物组以金黄色葡萄球菌（Staphylococcus aureus）为优势菌群，该菌具备形成生物膜（biofilm）的能力。
目的：本研究旨在评估金黄色葡萄球菌生物膜对特应性皮炎病程的影响。
方法：本研究纳入56名成人特应性皮炎患者，以SCORAD指数（SCORAD）评估疾病严重程度。从患者前鼻孔、皮损皮肤及非皮损皮肤中分离得到金黄色葡萄球菌菌株，采用微量板法检测其形成生物膜的倾向。将微生物学检测结果与临床参数及总IgE浓度进行相关性分析。
结果：在前鼻孔与皮损皮肤样本中，生物膜形成阳性的金黄色葡萄球菌菌株检出率分别为76.3%（29/38）与79.1%（34/43）（p > 0.05）；非皮损皮肤样本中检出率为48.5%（16/33）（p > 0.05）。与定植非生物膜形成型菌株的患者相比，定植前鼻孔金黄色葡萄球菌的患者，其总SCORAD评分、客观SCORAD评分及其各项构成指标（皮损范围、皮肤干燥程度）的平均分值均显著更高，且近一年内急性发作期的最大皮损范围也更大。皮损部位定植生物膜形成型金黄色葡萄球菌与疾病稳定期的皮损范围平均分值升高存在关联。
结论：本研究结果提示，定植于前鼻孔的金黄色葡萄球菌菌株形成生物膜的能力与特应性皮炎的病程存在相关性。生物膜似乎在该病原体实现皮肤大面积扩散与持续定植的过程中发挥关键作用。破坏金黄色葡萄球菌生物膜或可对特应性皮炎的病程产生积极影响。