Cultural and Nutritional Studies of Trichophyton Gallinae and Trichophyton Megnini

SUMMARY

1.	A review of the history and classification of Trichophyton megnini and Trichophyton gallinae is given.
2.	Nutritional and morphological studies of strains available further emphasize the differences between these two species which have so often been confused in the past.
3.	All of the T. megnini strains were shown to require the addition of the amino acid l-histidine in order to grow on an ammonium nitrate-dextrose medium. L-histidine could not be replaced by any other amino acid or combination of amino acids. In the presence of histidine, the amino acids which provided greatest stimulation were: asparagine, glutamine, and arginine. All strains were somewhat inhibited by hydroxyproline. The minimum effective concentration of histidine was determined in NH4NO3 broth, and also in an amino acid mixture complete except for hydroxyproline and histidine.
4.	No stimulation of the growth of the T. megnini strains was observed upon the addition of water-soluble or fat-soluble vitamins to a histidine medium. Vitamin K3 had an inhibitory effect.
5.	Spore production of most of the T. megnini strains was stimulated by growth on media rich in amino acids, such as trypticase-dextrose agar. Further addition of histidine to this medium did not increase growth or spore production. The microconidia and macroconidia of T. megnini are described.
6.	Five strains studied showed morphological characteristics suggestive of T. gallinae. These strains grew well on inorganic nitrogen medium and were not stimulated by the addition of casein or amino acids.
7.	No stimulation of the T. gallinae strains was observed upon addition of water-soluble or fat-soluble vitamins.
8.	One recently isolated strain showed microconidia and macroconidia characteristic of T. gallinae.
9.	The physiologic and morphologic characteristics of T. megnini and T. gallinae are summarized.