The effect of sodium chloride on the growth and morphology of dermatophytes and some other keratolytic fungi

Abstract

A study of the influence of various concentrations of NaCl on 21 species of dermatophytes and other keratolytic fungi was made. Based on the sensitivity of the species to various concentrations of NaCl, it was possible to divide them into five groups. Microsporum ferrugineum and Trichophyton concentricum and T. tonsurans were the most sensitive to NaCl and were inhibited by 5%. The greatest number of species were inhibited by 12% NaCl. The fungi most tolerant to NaCl were M. cookei and M. nanum, and T. mentagrophytes, T. schoenleinii, and T. terrestre. These species were inhibited by 15%. NaCl prevented any variant change in Epidermophyton floccosum, T. mentagrophytes, and M. gypseum, but promoted a change in phenotype in M. audouinii and M. cookei, and T. gallinae. It is suggested that the word "pleomorphism" be replaced by the term sterile albinism. This term refers to that kind of cultural change when there is no evidence of sporulation and the white fluffy mycelium consists of fine sterile hyphae.Sterile albino strains of E. floccosum were induced to form macroconidia on Sabouraud cycloheximide chloramphenicol gentamicin agar (SCCGA) containing 3–5% NaCl. Also, M. audouinii formed microconidia and macroconidia in velvety growth cultured on SCCGA containing NaCl.