Temporal Variation in Staphylococcus aureus Protein A Genotypes from Nose and Skin in Atopic Dermatitis Patients

Abstract

<b><i>Background:</i></b> <i>Staphylococcus aureus</i> colonization is associated with disease severity in patients with atopic dermatitis (AD). <b><i>Objective:</i></b> To investigate temporal variation in <i>S. aureus</i> protein A gene (<i>spa)</i>-types isolated from the nose and lesional skin and the correlation of <i>spa</i>-types with disease severity. <b><i>Results:</i></b> This study included 96 adult AD patients who were assessed at baseline (T0) and after a strict 2-week follow-up period (T1) in which treatment was standardized with a topical corticosteroid. Fifty-five different <i>spa</i>-types were detected in the nose and skin cultures. Seventy-three patients were colonized with <i>S. aureus</i> in the nasal cavity at both time points (persistent carriership), 59 of whom (81%) had identical <i>spa</i>-types over time. For skin samples, 42 (75%) of the 56 persistent skin carriers had identical <i>spa</i>-types over time. The same <i>spa</i>-type was carried in the nose and skin in 79 and 77% of the patients at T0 and T1, respectively. More severe disease was not associated with specific <i>spa</i>-types or with temporal variation in <i>spa</i>-type. <b><i>Conclusion:</i></b> <i>S. aureus</i> strains in AD are highly heterogeneous between patients. The majority of patients carry the same <i>spa</i>-type in the nose and skin without temporal variation, suggesting clonal colonization within individual patients. No predominant <i>spa</i>-type or temporal variation is associated with increased disease severity.