The effect of high concentrations of NaCl, KCl and MgCl2 in the culture media on the growth and conidiogenesis of three dermatophyte species.

Abstract

The influence of high concentrations of NaCl, KCl and MgCl2 on the growth and conidiogenesis was examined on some strains of dermatophytes, namely Microsporum audouinii, M. langeronii and Arthroderma vanbreuseghemii. The salts examined were incorporated by serial concentrations ranging from 0.5 to 8.0% or more into the basal medium composed of peptone, dextrose and agar. The effects of high concentrations of all these salts on the growth, micro- and macroconidia production were similar with slight differences among the salts. Microconidia were produced within a relatively wide range of salt concentrations whereas macroconidia were produced within a range of salt concentrations narrower than those for microconidia. At about 8% or more, the production of micro- and macroconidia tended to decrease in number and was replaced by arthroconidia. The results indicate that the utilization of high concentrations of salts is applicable not only for the identification of dermatophytes which lack characteristic conidia production but for the further clarification of the biological roles of each conidial form.