Prevalence of Staphylococcus aureus skin colonization and its correlation with serum interleukin-22 levels, disease severity, and body mass index in patients with psoriasis.

There is limited data regarding the correlation between interleukin-22 (IL-22) levels and psoriasis severity or body mass index (BMI). In addition, few studies have investigated the prevalence of different toxigenic strains of Staphylococcus aureus in psoriasis and their association with disease severity and BMI. This cross-sectional study examined the prevalence of S. aureus skin colonization in patients with psoriasis and its correlation with serum IL-22 levels, disease severity, and BMI. S. aureus isolates were identified, and their toxigenic strains were detected by polymerase chain reaction. Serum IL-22 levels were measured using an enzyme-linked immunosorbent assay. A majority of patients (60.2%) demonstrated S. aureus colonization in both lesional and nonlesional skin. In lesional skin, 45.2% of patients were colonized by toxigenic strains, with the SEB strain being the most prevalent (24.7% cases). In contrast, 47.3% of patients showed colonization by nontoxigenic strains in nonlesional skin. Colonization by toxigenic strains was significantly higher in lesional skin, whereas colonization by nontoxigenic strains was markedly higher in nonlesional skin (p = 0.001 for each). Both psoriasis severity and pruritus intensity were significantly greater among patients colonized with toxigenic strains (p = 0.001 each). Mean serum IL-22 levels were also significantly higher in patients with severe disease and pruritus (p = 0.001 each). Moreover, serum IL-22 levels showed strong positive correlations with BMI, psoriasis severity, and pruritus severity (p = 0.002, 0.0001, and 0.0001, respectively). This study highlights significant associations between S. aureus colonization, particularly the toxigenic strain SEB and psoriasis severity, serum IL-22 levels, and BMI. Further large-scale studies are warranted to validate these findings.