THE ROLE OF EXTRACELLULAR POLYSACCHARIDE SUBSTANCE PRODUCED BY STAPHYLOCOCCUS-EPIDERMIDIS IN MILIARIA

Background: Previous studies have indicated that cutaneous bacteria, p articularly coagulase-negative staphylococci, play a role in the patho genesis of miliaria. An accumulation of periodic acid-Schiff (PAS)-pos itive material has been described as blocking the sweat duct in miliar ia. Furthermore, a PAS-positive extracellular polysaccharide substance (EPS) has been identified as a product of some strains of Staphylococ cus epidermidis. Objective: We evaluated the relative ability of vario us species of coagulase-negative staphylococci to induce miliaria with particular reference to the potential role of EPS. Methods: We inocul ated various strains of coagulase-negative staphylococci on the volar forearms of subjects under an occlusive dressing coupled with thermal stimulation. Ability to induce miliaria as well as microbiologic, hist ologic, and immunostaining features were evaluated. Results: Miliaria was induced only with strains of S. epidermidis; other species includi ng S. haemolyticus, S. hominis, S. cohnii, S. saprophyticus, and S. si mulans were not capable of inducing miliaria. Moreover, only S. epider midis strains capable of producing EPS were capable of inducing miliar ia. Conclusion: Our data indicate that EPS is the PAS-positive materia l that obstructs the delivery of sweat to the skin surface in miliaria and therefore demonstrate that the EPS produced by S. epidermidis pla ys a central role in the pathogenesis of miliaria. Furthermore, in a s urvey of staphylococcal flora isolated from 68 subjects, EPS-producing strains were found to be common.