Prevalence and clinical distribution of the sbi immune-evasion gene among Staphylococcus aureus isolates from adults with atopic dermatitis

This study was conducted as part of a larger cross-sectional investigation of the microbiological profile of adults with atopic dermatitis (AD) in Kuwait . Staphylococcus aureus ( S. aureus ) second immunoglobulin-binding protein (Sbi) is an immune-evasion protein implicated in host immune modulation and inflammatory responses; however, its prevalence and clinical distribution in AD-associated S. aureus isolates remain poorly characterized. This study investigated the prevalence of the sbi gene among nasal and lesion-associated S. aureus isolates obtained from adults with AD and evaluated its association with disease severity using the sea and mecA genes as reference virulence and resistance markers. A total of 101 adults with AD were included. Nasal S. aureus positivity was recorded in 54/101 (53.5%) participants, while 13/21 (61.9%) lesion swabs yielded S. aureus . Among nasal isolates, sbi , mecA and sea genes were detected in 50/54 (92.6%), 38/54 (70.4%), and 10/54 (18.5%) isolates, respectively. Among lesion isolates, the corresponding prevalences were 11/13 (84.6%), 5/13 (38.5%), and 1/13 (7.7%). The sbi gene was frequently detected across all severity categories, and no association between nasal sbi detection and AD severity was detected in this cohort ( p = 1.000). Only four nasal isolates were sbi -negative, limiting the ability to assess this association. The sea and mecA genes were also examined as reference virulence and resistance markers. These findings describe frequent sbi detection but do not establish Sbi expression, functional activity or a causal contribution to AD severity.