Exoantigen test for differentiation of Exophiala jeanselmei and Wangiella dermatitidis isolates from other dematiaceous fungi

Abstract

Concentrated (25x) exoantigens of 105 isolates of pathogenic and saprophytic dematiaceous fungi and 3 isolates of Sporothrix schenckii were analyzed by the microimmunodiffusion method. The reagents used were nonadsorbed and adsorbed sera produced in New Zealand rabbits. One set of rabbits was immunized with soluble antigens of a 1-month-old culture of Exophiala jeanselmei (ATCC 34123), and the other set was immunized with soluble antigens from a culture of Wangiella demattidis (ATCC 28869). The reference antigens were 25 x-concentrated exoantigens of the above cultures. This exoantigen test permitted the differentiation of E. jeanselmei and W. dermatitidis from one another as well as from other Exophiala species, Fonsecaea species, Phialophora species, Cladosporium species, Rhinocladiella species, and Sporothrix schenckii by presence or absence of lines of identity or of partial identity, or lines of nonidentity. Using adsorbed serum eliminated the problems with cross-reactivity seen with nonadsorbed serum. Thus, with an adsorbed serum as the reagent, it was possible to presumptively differentiate E. jeanselmei and W. dermatidis from one another and from other dematiaceous fungi.

Developments in Fungal Taxonomy

“…These studies should be complemented by physiological tests, the most important of which measure assimilation of lactose, D-glucuronate, D-galacturonate, nitrite, creatine, and creatinine, tolerance to cycloheximide, and growth to different temperatures (117,118). Some species have been distinguished by approaches based on coenzyme Q analysis (516,596), karyology (530), sequence analysis of the chitin synthase gene (59), serology (157,332), and flow cytometry (528). Recently, Uijthof and de Hoog (546) used type strains to perform RFLP analysis on all the described taxa of the genus and showed that most of them are bona fide species.…”

Physiological Characteristics of Environmental Isolates of Pathogenic Dematiaceous Fungi

“…However, all of the procedures are limited by the lack of sufficient physiological and biochemical data. The use of serological methods (2,5) to aid identification has also been limited by lack of commercially available specific antisera (13). The present study was, therefore, carried out to investigate some physiological characteristics of pathogenic dematiaceous fungi that could supplement the morphological characteristics in the identification of these these fungi.…”

Evaluation of proteolytic activity to differentiate some dematiaceous fungi

“…The same results were reported by Conti-Difaz et al (5) between isolates from the environment of either E. jeanselmei or W. dermatitidis and isolates from human sources. We have previously demonstrated (8,9) by use of the exoantigen test that environmental and clinical isolates of the same species could not be differentiated. Serological studies (19) have shown that there are no differences between isolates of C. carrionii from the environment and those causing human disease.…”