Skin colonization with staphylococcus aureus (S.aureus) is a characteristic
feature of atopic dermatitis (AD). Bacterial superantigenes represent one important
startegy by which infectious agents can stimulate the immuneresponse and may have
apotential role in triggering IgE respons. The objective of our work was to study the
prevalence of S.aureus colonization in atopic skin and to examine whether the
presence of superantigen-producing S.aureus straims correlated with increased
severity of skin inflammation. We aimed also at studying the possible additive effect
of bacterial superantigen on allergen induced cutaneous inflammation . (30) Al)
patients and (10) normal control subjects \ '‘ ere included. The items studied xerc:
prevalence of bacterial colonization of cc/ ematous and non inNokvd snc..
staphylococcal cnterotoxin production %%Inch included staphylococcal enterotoxin A
(SEA) ' staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin-I
(TSST-I) by western blot technique. and determination of specific IgE antibody
responses to a number of food and aero allergens by immunoblot test.
S.aureus colonization was found in 2% of normal subjects contrasting sharply
to the high colonization rate in AD patients that ranging from 50% in non involved
skin and up to 80% in involved sites. Superanticenic S.aureus producing strains Were
detected in 50% of bacterial colonies in intlammed sites and 30% in non irdlammed
sites. Dermatitis severity scores correlated shmificantiv to the presence of
superantigen producing isolates. Specific IgE antibodies to food allergens (cow milk.
egg white. soyabeans) and aero allergens (House dust mite, grass pollens. cat. dog)
were significantly higher in AD patients than normal. Cases with severe inflammtion
and highest clincal score were -repersented by patients colonized by S.aurcus
producing toxins and highly reactive to specific allergens. It was concluded that
S.aureus superantigens have a possible role in exacerbation of atopic dermatitis. |
