Diversity of Staphylococcus aureus clonal complex in Atopic Dermatitis

Background: Atopic dermatitis (AD) is a prevalent disease with significant impact on physical health and quality of life. S. aureus has been directly correlated to disease severity, and may also be a contributing causal factor in the pathogenesis of AD. In the present study associations between genetic lineages of S. aureus, demographic factors, presence of other atopic diseases, disease severity, and filaggrin gene (FLG) mutations are examined in AD patients. Methods: 101 adult AD patients were included in the study. Bacterial swabs were taken from lesional skin, non-lesional skin and nose. Swabs positive for S. aureus were characterized by spa and the respective clonal complex (CC) type assigned. Patients were characterized with respect to disease severity (SCORAD) and FLG mutations. Results: 73% of the patients were colonized with S. aureus. No specific bacterial lineage was linked to disease severity. More than 90% of the patients carried only one CC type in the three different sampling sites. S. aureus CC1 clonal lineage was more prevalent in patients with FLG mutations than in wild-type patients. Distribution of S. aureus clonal lineages differed from lineages associated with nasal carriage or bacteraemia, with an increased prevalence of CC1 and decreased prevalence of CC30. Conclusion: Differences in prevalence of certain CC types in AD patients as compared to healthy nasal carriers or to other patient groups, and the increased prevalence of CC1 in patients with FLG mutations suggest that clonal differences in S. aureus are important for colonization of AD skin.