BACTERIAL INVASION OF STRATUM CORNEUM IN ERYTHRASMA .I. ULTRASTRUCTURAL EVIDENCE FOR A KERATOLYTIC ACTION EXERTED BY CORYNEBACTERIUM MINUTISSIMUM

[摘要] The process of bacterial invasion of the stratum corneum in erythrasma was studied. Ten culturally proven, untreated patients with fluorescent crural and/or axillary lesions were used. Multiple biopsy specimens from each patient were fixed simultaneously using either a procedure for bacteria (Ryter-Kellen-berger) or a method for adequate preservation of the skin (Caulfield). Study of thin sections revealed large numbers of diphtheroids which were seen in different locations within the upper 1/3 of the stratum corneum: on the skin surface; in the intercellular spaces; within cells; penetrating the cells from the intercellular spaces or directly from the skin surface. Whereas most of the free organisms showed a homogeneous fine structure, intracellular bacterial were quite pleomorphic. Dividing organisms were numerous on the surface, and were abundant within cells. The stratum corneum was thicker than normal, with the cells disrupted at the sites of bacterial penetration. In the invaded keratinized cells, cytoplasmic areas of decreased electron density, observed regularly around intracellular bacteria, clearly showed a dissolution of the normal keratin fibrils. This change is probably the result of a keratolytic action exerted by C. minutissimum.