The Role of Staphylococcus Aureus Types and Toxin-Producing Ability in Pediatric Atopic Dermatitis and its Association with Disease Severity

Background: The skin of patients with atopic dermatitis has a high susceptibility to staphylococcus aureus (S. aureus) colonization known to produce toxins with super antigen (SAgs) activity which are a family of potent immune-stimulatory exotoxins and may aggravate AD. The aim of this research was to evaluate the role of staphylococcus aureus types and toxin-producing ability in pediatric atopic dermatitis and its association with disease severity. Materials and Methods: In this cross-sectional study, fifty-two patients with AD were evaluated for clinical severity of disease using severity scoring of atopic dermatitis (SCORAD) index. Swabs were taken from their skin and S. aureus was isolated, then the mecA, SCCmec types and agr genes besides exotoxins with super antigen properties, Hla and TSST genes were evaluated by performing polymerase chain reaction (PCR). Results: Staphylococcus aureus was isolated in 38 (73.07%) out of 52 AD patients. The SCORAD index and AD severity were strongly correlated with S. aureus colonization (P=0.00). The staphylococcal alpha-hemolysin (Hla) was the predominant toxin gene found in AD patients, Hla was produced in 22 patients (57.9%). The toxic shock syndrome toxin-1 (TSST-1) gene was found in 12 (31.6%) isolates and, in 11 patients both TSST-1 and Hla toxin gene were detected.  There was no significant relationship between the presence of TSST1 and Hla gene and the severity of the disease Hla (P=0.11 and P=0.08, respectively). Conclusion: AD severity based onthe SCORAD index was strongly correlated with S.aureus colonization, and the most frequent super antigen gene present in S. aureous isolates was that coding for (Hla).

Keywords:

Atopic dermatitis , Colonization , Staphylococcus aureus , Toxin gene