1Zaghloul W, 2Abdel-Khabir A and 2El-Sohafy M
Departments of 1Microbiology & Immunology and 2Dermatology & Andrology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Forty two patients with atopic dermatitis (AD) and twenty age and sex matched healthy subjects were included in the present study. Swabs from lesional skin and anterior nares were taken and cultured for identification of bacteriological growth. S. aureus strains isolated from both skin and nose were investigated for superantigen production (Enterotoxins A-D) by reverse passive latex agglutination (RPLA) test. Results of bacteriological culture revealed that the incidence of S. aureus colonization in patients skin (71.4%) was significantly higher than in control group (30%) and the colonization was more significant in patients with wet lesions than those with dry lesions. There was no significant difference in the nasal carrier between patients (45.2%) and control group (40%). As regards the superantigen production, 53.3% of S. aureus strains (38.1% of the total cases) were found to secrete enterotoxins, mainly Staphylococcal enterotoxin B and C (SEB and SEC) while in the control group only 33.3% of isolated S aureus strains (10% of the total group) were enterotoxins producers. Treatment of 16 cases with topical steroids alone for one week resulted in reduction of S. aureus colonization by 62.5% and enterotoxins production by 60%. In conclusion, skin lesions of AD are frequently colonized with superantigens producing strains of S. aureus. These superantigens could act as a trigger or exacerbating factor in the pathogenesis of atopic dermatitis. Topical steroid therapy, significantly reduced colonization of superantigens producing S. aureus in skin lesions of atopic dermatitis and induced clinical improvement.