Ultrastructural studies on experimental hair infections in vitro caused by Trichophyton mentagrophytes and Trichophyton rubrum.

Experimental infections with Trichophyton mentagrophytes and Trichophyton rubrum were performed on human hair in vitro and studied by conventional light microscopy, scanning (SEM) and transmission (TEM) electron microscopy. The penetrations visible by light microscopy in hair infected with T. mentagrophytes appeared at SEM as disrupted surface areas with perforating holes. T. rubrum-infected hair displayed minute perforations and less conspicuous cuticular damages seen at SEM and TEM. In both organisms multiple tiny perforating holes were observed at SEM previously unnoticed in experimental hair infections. From a morphological point of view the differences between the fungi investigated in this experimental system seem to be more of a quantitative nature than involving different mechanisms of action.