Comparison of Strains of Sporotrichum Schenckii Isolated from Nature.

Howard, Dexter H. (University of California, Los Angeles) and G. F. Orr. Comparison of strains of Sporotrichum schenckii isolated from nature. J. Bacteriol. 85:816-821. 1963.-Several strains of fungi, tentatively considered to be members of the genus Sporotrichum, have been isolated from soil and from other sources in nature. The striking morphological similarity of these isolates to strains of S. schenckii led to a comparative study of their biological properties. Nine strains of Sporotrichum from nature were compared with twelve strains of S. schenckii isolated from cases of clinical sporotrichosis. The nine saprophytic isolates were indistinguishable microscopically and macroscopically from strains of pathogenic S. schenckii when cultures were prepared on a variety of media incubated at 28 C. Only two of the nine saprophytic isolates were able to grow at 37 C. These two strains partially converted, at this temperature, to a yeast-cell phase of growth. The blastospores comprising this phase of growth were similar to those produced by S. schenckii under the same circumstances. Six of the nine saprophytes were essentially avirulent for mice. The remaining three strains had a very limited capacity to produce disease in experimental animals. The isolates are currently regarded as variants of S. schenckii.