Growth, Colonial Size and Sporulation of Lyophilized Cultures of the Genus Trichophyton on Agar Media

Abstract

RybnikH A.: Growth, Colonial Size and Sporulation of Lyophilized Cultures of the Genus Trichophyton on Agar Media. Acta vet., Brno, 55, 1986: 73 -80. Lyophilized cultures of 4 species of the genus Trichophyton Malmsten 1845 were diluted with saline after one year of storage and inoculated onto agar media. Trichophyton equinum grew best on malt media, T. mentagrophyfes on Mycological Agar, T. terrestre on Trichophyton Agars 1, 4 and 5, and T. verrucosum on Sabou­ raud's agar. The rate of colonial size increase of all the four cultures was highest on Sabouraud's agar, malt media and Mycological Agar. The formation of micro­ conidia showed the highest values on malt media with all the cultures except T. terrestre which sporulated best on Sabouraud's agar. It is concluded that malt agar media and Sabouraud's agar are suitable culture media for recultivation of lyophilized dermatophyte cultures. Dermatophyte lyophilizate, recultivation, colonial size, formation of microconidia. Cultures of microscopic fungi deposited in culture collections as well as those used for pro­ duction purposes undergo gradual loss of viability on long-term storage. In recultivating frozen­ lyophilized or otherwise preserved fungal strains it is therefore necessary to choose optimum procedures and conditions that would allow one to obtain viable, well-growing and sporulating cultures. One of the major factors involved is the choice of a suitable culture medium. Its choice may also considerably affect the results of testing fungal cultures for their growth and sporulation capacity and may lead to changes in the characteristics of the strains on passage. These aspects are particularly important in dermatophytic fungi, causative agents of mycoses in numerous animal species and man. The present study is concerned with the choice of agar culture media for recultivation, growth and sporulation of four species of the genus Trichophyton maintained in the lyophilized state for one year. These were three zoophilic dermatophytes, namely T. equinum, T. mentagrophytes and T. verrucosum, and one geophilic species, T. terrestre, which lives as a saprophyte on keratin structures in soil and very rarely attacks man and animals.