ISOLATION OF DERMATOPHYTES: A New Procedure for Use in the Presence of Saprophytic Fungi, Especially in Mixed Cultures and from Leather

V ARIOUS investigations in this laboratory have required the microbiologic examination of worn shoes, with the microflora present being large in number and varied in type and including many molds. Generally, the saprophytic molds far outnumber and outgrow the pathogenic types, so that isolation or determination of the numbers of pathogens is nearly impossible. Therefore a medium capable of a selective preference for the dermatophytes over the saprophytes would be beneficial. The mediums commonly used for the cultivation of pathogenic fungi have no inherent differential powers for the isolation of dermatophytes when saprophytes are present. Various investigators have reported difficulty in the isolation of dermatophytes from highly contaminated sources. Weidman 1 wrote that "several workers (personal communications) have failed in attempts to demonstrate dermatophytes in old shoes, etc.; in each case it was on account of the rank overgrowth of saprophytic molds. Even were the dermatophytes present and