DOI: 10.1177/03000605261497554 ISSN: 0300-0605
Nasal methicillin-resistant
Staphylococcus aureus
in adult atopic dermatitis: Severity and virulence associations—A cross-sectional study
Athoob A Jomah, Yasmine Alshammari, Amani H Al-Fadhli, Shehab Ahmad Al-Dhafiri, Khalifa Al Benwan, Atlal Allafi, Mohammad Alenezi, Anwar Al Banaw
Objectives
To investigate the prevalence of nasal methicillin-resistant
Staphylococcus aureus
(MRSA) colonization among adults with atopic dermatitis and explore its association with disease severity.
Methods
This cross-sectional study included 100 adults (≥18 years) with dermatologist-confirmed atopic dermatitis who attended dermatology outpatient clinics in Kuwait. Patients with nonatopic eczema, major systemic illnesses, or skin malignancy were excluded. Disease severity was assessed using the validated Investigator’s Global Assessment for Atopic Dermatitis. Nasal swabs were collected, and
S. aureus
isolates were identified using culture, Gram staining, and catalase and coagulase tests, followed by confirmation using the VITEK® 2 system. Methicillin resistance (mecA) and selected staphylococcal virulence genes, including the classical (
sea
,
seb
,
sec
,
sed,
and
see
) and nonclassical staphylococcal enterotoxins (
seg
,
seh,
and
sei
), Panton–Valentine leukocidin (
pvl
), and toxic shock syndrome toxin-1 (
tsst-1
) were determined using polymerase chain reaction. Antimicrobial susceptibility profiles were assessed using the Clinical and Laboratory Standards Institute disk diffusion method.
Results
S. aureus
colonization is a key feature of atopic dermatitis and is closely associated with disease activity. This study investigated the prevalence of nasal MRSA colonization among adults with atopic dermatitis and examined its association with disease severity and virulence gene carriage. Overall, 53% of patients were colonized with
S. aureus
, of whom 71.7% carried MRSA. MRSA colonization was significantly associated with older age and greater disease severity. Virulence gene analysis in MRSA isolates revealed higher frequency of
seg
and
sei
, whereas the presence of
sea
and
tsst-1
were significantly associated with more severe atopic dermatitis.
Conclusions
Adults with atopic dermatitis showed a high prevalence of nasal MRSA colonization. The predominance of enterotoxin gene cluster genes and the association of
sea
and
tsst-1
with greater disease severity highlight the potential clinical importance of nasal MRSA as a reservoir of virulent strains in atopic dermatitis.