The Nutrition of Trichophyton Tonsurans

Abstract

Prichophyton tonsurans is an important agent of epidemic ringworm in many areas of the world, causing a disease which may involve the hair, skin, and nails. Infections occur in both children and adults and these are often extremely difficult to cure. During the past eight years, ring? worm due to T. tonsurans has become a health problem in the United States, and better methods of diagnosis, treatment, and control are needed (7). Accurate diagnosis of P. tonsurans ringworm cannot be made on a clinical basis alone, but is dependent upon microscopic examination of clinical materials, coupled with the isolation and identification of the causative agent. The final diagnosis rests, therefore, on laboratory studies of the fungus itself. The usual procedure is to identify the fungus on the basis of its gross and microscopic morphology as observed on a standard medium such as Sabouraud dextrose agar. Experience in this laboratory and others indicates, however, that this is often difficult. This is because P. tonsurans grossly presents a highly varied morphology, and microscopically reveals no distinctive spore form or spore arrange? ment which can be completely relied upon for identification purposes. Identification must depend, therefore, upon a group of rather variable characteristics. Furthermore, certain strains may be difficult to identify because other dermatophyte species, particularly Prichophyton menta? grophytes and Prichophyton rubrum, may at times present similar mor? phological characteristics. The present investigation was undertaken in order to learn the funda? mental nutritional requirements' of P. tonsurans. It was hoped that nutritional studies of P. tonsurans would reveal certain physiological characteristics of the organism which would be of value in the labora? tory identification of this fungus. Such studies perhaps would supply also some information concerning the general physiology of this fungus and of its ability to invade tissues. The nutrition of T. tonsurans has been studied previously. In 1943,