Patients with Atopic Dermatitis Colonized with Staphylococcus aureus Have a Distinct Phenotype and Endotype

Abstract

Patients with atopic dermatitis (AD) are commonly colonized with Staphylococcus aureus (AD S. aureus), but what differentiates this group from noncolonized AD patients (AD S. aureus) has not been well studied. To evaluate whether these two groups have unique phenotypic or endotypic features, we performed a multicenter, cross-sectional study enrolling AD S. aureus (n = 51) and AD S. aureus (n = 45) participants defined by the presence or absence of S. aureus by routine culture techniques and nonatopic, noncolonized control individuals (NA S. aureus) (n = 46). Filaggrin (FLG) genotypes were determined, and disease severity (Eczema Area and Severity Index, Rajka-Langeland Severity Score, Investigator's Global Assessment score, Numerical Rating Scale, and Dermatology Life Quality Index) was captured. Skin physiology was assessed (transepidermal water loss [TEWL], stratum corneum integrity, hydration, and pH), and serum biomarkers were also measured. We found that AD S. aureus patients had more severe disease based on all scoring systems except itch (Numerical Rating Scale), and they had higher levels of type 2 biomarkers (eosinophil count, tIgE, CCL17, and periostin). Additionally, AD S. aureus patients had significantly greater allergen sensitization (Phadiatop and tIgE), barrier dysfunction (TEWL and stratum corneum integrity), and serum lactate dehydrogenase (LDH) than both the AD S. aureus and NA S. aureus groups. FLG mutations did not associate with S. aureus colonization. In conclusion, adult patients with AD who are colonized on their skin with S. aureus have more severe disease, greater type 2 immune deviation, allergen sensitization, barrier disruption, and LDH level elevation than noncolonized patients with AD.

Can antibiotics be harmful in atopic dermatitis?

“…Interestingly, a Cochrane review concluded that data was lacking for highly beneficial outcomes with exclusive use of antibiotics in the management of AD. This is consistent with studies dating back to the early 1970s by Leyden and Kligman that patients with AD primarily benefit from antibiotics when they are colonized with more than one million bacteria per cm of skin. Therefore, in the absence of an exudative or crusted skin lesion, the usefulness of antibiotics can be debated and their ability to completely eliminate S. aureus colonization is dubious.…”

“…Atopic dermatitis (AD) is a pruritic chronic inflammatory skin disease associated with Staphylococcus aureus colonization . This is a clinically significant finding because S. aureus colonization is associated with increased AD severity, a more allergic diathesis and skin‐barrier dysfunction . This propensity toward S. aureus colonization is complex but begins with attachment of S. aureus to bacterial adhesion sites within the skin.…”

Personalized medicine—concepts, technologies, and applications in inflammatory skin diseases

“…The cutaneous microbiome, on the other hand, is clearly associated with AD, as a vast majority (>90%) of AD patients have their skin colonized with Staphylococcus aureus, compared to only 5% of healthy controls . In addition, S. aureus positive AD patients seem to have more severe disease, higher levels of Type 2 biomarkers (CCL17, POSTN), allergen sensitization (IgE), and barrier dysfunction (higher TEWL) than non‐colonized AD controls . Also, in a prospective study on children with AD, an increase in the proportion of S. aureus and a concomitant decrease in bacterial diversity preceded worsening (flare) of AD .…”

Atopic Dermatitis: Collegium Internationale Allergologicum (CIA) Update 2019

“…Compared to the noncolonized, S. aureus -colonized AD patients have more severe AD, higher blood eosinophil numbers, and higher total and allergen-specific IgE levels, as well as a greater barrier dysfunction as assessed by a transepidermal water loss and stratum corneum (SC) integrity that are not associated with filaggrin mutations [9]. …”