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The role of Staphylococcus aureus in atopic dermatitis

Abstract number: R2290

Prignano G., Capitanio B., Gallo M.T., Pascolini C., Cilli L., De Santis A., Anastasia F., Vespaziani M., Greco E., Ensoli F.

Objectives: Atopic dermatitis is a chronic inflammatory skin disease associated with colonisation of the skin with Staphylococcus aureus known to produce toxins with superantigen activity. A correlation between the severity of the eczema and colonisation with S. aureus has been demonstrated and it has been determined that bacterial colonisation is an important factor aggravating skin lesions. Recent studies revealed that nasal carriage of S. aureus (NCSA) could be an important risk factor for subsequent infection including MRSA (methicillin-resistant S. aureus). The aim of this study was to determine the prevalence of S. aureus and MRSA in the lesional and nonlesional skin, and in the anterior vestibule of the nose in patients affected by atopic dermatitis. In addition we also examined the relationship between S. aureus skin lesion and nasal colonisation, the production of toxins and the presence of nasal colonisation in patient's cohabitants.

Methods: Nasal and skin (lesional and nonlesional) swabs cultures for bacterial isolation were obtained from 94 children affected by atopic dermatitis. Nasal swabs were taken from 15 patients' cohabitants. S. aureus strains were tested for emo-agglutination passive reverse (Oxoid, UK) for detecting the toxins SEA, SEB, SEC, SED and TSST-1.

Results:S. aureus colonisation prevalence estimates were 36% in the lesional skin of atopic dermatitis patients, in the same group of patients the percentage of S. aureus in the anterior vestibule of the nose was 94.4%. In the group of study we found the presence of MRSA with a prevalence of 7.9% in the lesional skin and 3% in the nose. 65% of S. aureus strains isolated from patients releases staphylococcal enterotoxins type A, B, C, D (SEA-SEB-SEC-SED) and/or TSST-1. We observed that all positive patients to S. aureus had at least one positive cohabitant and that the presence and the kind of enterotoxins in strains isolated from cohabitants coincide to 100% with those of the patients.

Conclusion: This data focus the importance of the nasal carriage as risk factor for the development of skin lesions in atopic dermatitis patients. It's important to redefine the exact pathogenetic role of S. aureus for a better therapeutic strategy as S. aureus, in particular strains producing toxins, could be considered a trigger or aggravating atopic dermatitis. In the current diagnostic practice is appropriate to include the research of S. aureus in the patients' family cohabitants.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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