Multilocus-sequence typing reveals clonality of Staphylococcus aureus in atopic dermatitis

Area of Science:

• Microbiology
• Dermatology
• Genetics

Background:

• Atopic dermatitis (AD) severity is linked to Staphylococcus aureus colonization.
• S. aureus can displace normal skin microbiota and other S. aureus strains.
• Limited data exists on S. aureus strain relationships and molecular characteristics across different body sites in AD.

Purpose of the Study:

• To investigate the genetic relationships of S. aureus isolates from lesional skin, nonlesional skin, and anterior nares in AD patients using multilocus sequence typing (MLST).
• To characterize dominant S. aureus clones found in these microniches.

Main Methods:

• Sixty-three individuals with active atopic dermatitis were enrolled.
• Multilocus sequence typing (MLST) was performed on S. aureus isolates from ten moderate-to-severe AD patients colonized at all analyzed sites.

Main Results:

• Sequence types 7, 15, and 97 were most prevalent, associated with factors promoting dysbiosis, skin damage, and inflammation.
• 60% of patients carried clonal S. aureus strains across all sampled locations (skin and nares).
• Clonal carriage varied, with some patients showing strains on lesional/nonlesional skin or nonlesional skin/nares.

Conclusions:

• Identified S. aureus lineages appear adapted to colonize and dominate the AD microbiota.
• Targeting S. aureus reservoirs in anterior nares and nonlesional skin may be a strategy to mitigate AD severity.