Dermatophytosis

SUMMARY

The authors report the first case of dermatophytosis caused by Trichophyton raubitschekii in a patient from the State of Sdo Paulo with Tinea corporis lesions localized on the buttocks. Culture on Sabouraud-agar with cycloheximide permitted the isolation and identification of the fungus, and the diagnosis was confirmed by Dr. Lynne Sigler, University of Alberta, Canada. Systemic treatment with fluconazole, 150 mg/week for 4 weeks, in combination with topical treatment with isoconazole initially yielded favorable results, with recurrence of the lesions after the medication was discontinued. This is the fifth case of this dermatophytosis published in the Brazilian medical literature.

KEYWORDS: Trichophyton raubistschekii; Dermatophytosis; Tinea corporis

INTRODUCTION

In 1981, KANE et at.' reported anew species of Trichophyton isolated from epidermal scales of the skin of a patient from Toronto (Canada), which they called Trichophyton raubitschekii. This was a urease-positive dermatophyte similar to Trichophyton rubrum.

About 41 strains of this dermatophyte were then studied and compared to 10 strains of T rubrum and T mentagrophytes. According to KANE et al. (1981)1, this is an anthropophilic fungus

predominantly distributed in southeast and southwest Asia and in northeast India. In Brazil, CAIUBY et al. (1996)1, in Rio de Janeiro, identified 4 strains of this fungus isolated from Tinea corporis lesions.

The characteristics of this dermatophyte are as follows: colonies of moderately slow growth, elevated and reaching 25 to 30 mm, after 14 days at 25 IC in Mycosel agar. The colony surface is blood red or reddish brown, radially sulcated or granular and flat, covered with fine brown aerial mycelium. Some cultures may be red-purple in color and smooth, resembling T violaceum. The reverse may present yellowish bands in young cultures. Macroconidia and microconidia are abundant in primary isolations, and may decrease in subcultures. The macroconidia are cylindrical or cigar-shaped, measuring 46-51 pm in length by 4.8-6.3 pm in width. The microconidia are subspherical to spherical, piriform or club-shaped, measuring 4.8-6.4 x 3.2-4.8 gm

Dilated rounded cells can be produced in submersed filaments or occasionally by the disaggregation of macroconidia into I to 3 cell fragments. The fungus grows at 37 or- and is urease-positive- It does not perforate hair.

The species under study has been named after Prof F Raubitscheck, an American dermatologist and mycologist

The present paper reports the first case of dermatophytosis caused by Mchophyton mub#itschekii in a patient with dia corporis from the, State of SAo Paulo.

CASE REPORT

Patient T.A.A., registration number 599 at the Dermatology Clinic of Santa Casa (SP), a white female working as a fruit and vegetable seller, born and living in Sao Paulo, presented with Tinea corporis lesions localized on the buttocks. Mycologic examination was positive for dermatophyte arthroconidia. Culture on Sabouraud-agar with cycloheximide permitted the isolation of a fungus first identified as Trichophyton rubrum and then finally identified as Trichophyton raubitschekii Kane, Salkin, Weitzman et Smitka, 19811 (Fig.1). It is a urease-positive dermatophyte that does not perforate hair in vitro; its macroconidia are cylindrical or cigar-shaped and the microconidia are subspherical, piriform or club-shaped (Figs. 2 and 3).

The patient was treated systemically with fluconazole, 150 mg/week for 4 weeks, in combination with topical treatment with isoconazole. Favorable results were first obtained, followed by recurrence of lesions after the medication was discontinued.

DISCUSSION

According to KANE et al. (1997)', Trichophyton raubitschekii colonies may be confused with T violaceum or T rubrum because of the pigment they produce. The lesions they provoke are similar to those of Tinea corporis. Trichophyton raubitschekii has been considered by many mycologists to be a variant of T rubrum, as is also the case for T kanei and T fischeri.

T raubitschekii is quite similar to the velvety form of T rubrum and is distinguished from the latter by being urease-positive, also producing abundant macroconidia and microconidia in primary isolations. Some macroconidia are rounded, a characteristic rarely observed in T. rubrum. The teleomorph form of T raubitschekii has not been described. KANE et al. (1997)', in a chapter on the "Biological aspects in the identification of dermatophytes" elaborated a figure (Fig. 4) in which the species of the "T rubrum complex" are presented. T rubrum var. rubrum, T rubruni (hyaline variant), T rubrum (granular variant), T rubrum (velvety), T rubrum var. nigricans and T rubrum (golden form) were first considered. In turn, T. rubrum is related to T raubitschekii, T mentagrophytes (granular), M. persicolor, T kanei. T mentagropkytes (reddish), T mentagrophytes (velvety), T megnini, T krajdenii, T fischeri, and T mentagrophytes (cotton-like).

SUMMERBELL & KANE (1997)5, when describing T raubitschekii reported that in certain variants the colonies produce a red-purple pigment similar to T violaceum. They also pointed out that T raubitschekii is closely similar to the velvety variety of T rubrum, being differentiated from the latter by being urease-positive. Some microconidia are rounded, a fact that is not comnwn in T rubrum varieties.

RESUMO

Dermatofitose por Trichophyton raubitschekii. Registro do primero caso em Sao Paulo, Brasil

Os Autores registrar o primeiro caso de dermatofitose por Trichopkvion raubitschekii em paciente do Estado de Sao Paulo, com les6es de Tinea corporis localizada nas nAdegas. 0 cultivo em AgarSabouraud com cicloheximida perrnitiu o isolamento e identificaq5o do fungo, cujo diagn6stico foi confirmado pela Dr' Lynne Sigler, da Universidade de Alberta, Canadd. 0 tratamento sistemico com fluconazol, 150mg/semana por 4 semanas, associado ao, tratamento t6pico com isoconazol ofereccu inicialmente resultados favordveis, com recidiva clas lesbes, ap6s suspensdo do medicamento. Trata-se do quinto caso publicado na literatura medica nacional.

ACKNOWLEDGEMENT

We are grateful to Dr. Lynne Sigler, University of Alberta, Canada, for confirming the diagnosis and Creusa Paes Siqueira for typing the manuscript.

REFERENCES

1. CAJUBY, M.J.; MONTEIRO, P.C.F. & NISHIKAWA, M.M. - Isolation of Trichophyton raubitschekii in Rio de Janeiro (Brazil). J. med. vet. Mycol., 34: 361-363, 1996.

2. KANE, J. - The biological aspects of the Kane/Fischer system for identification of dermatophytes. In: KANE, J.; SUMMERBELL, R.; KRAJDEN, S.; SIGLER, L. & LAND, G. Laboratory handbook of dermatophytes. A clinical guide and laboratory handbook or dermatophytes and other filamentous fungi from skin, hair and nails. Belmont, Star Publishing Company, 1997. p. 81 - 129.

3. KANE, I.; SALKIN, I.F.; WEITZMAN, 1. & SMITKA, C.M. - Trichophyton raubitschekii sp. nov. Mycotaxon, 13: 259-266, 1981.

4. KANE, I.; SUMMERBELL, R.; KRAJDEN, S.@ SIGLER, L. & LAND, G. - Laboratory handbook of dermatophytes. A clinical guide and laboratory handbook of dermatophytes and other filamentous fungi from skin, hair and nails. Belmont, Star Publishing Company, 1997.

5. SUMMERBELL, R.C. & KANE, J. - The genera Trichophyton and Epidernopkyton. In: KANE, J.; SUMMERBELL, R.; KRAJDEN, S.; SIGLER, L. & LAND, G. Laboratory handbook of dermatophytes. A clinical guide and laboratory handbook of dermatophytes and other filamentous fungi from skin, hair and nails. Belmont, Star Publishing Company, 1997. p. 131-191.

Received: 18 June 1999 Accepted: 19 August 1999

Carlos da Silva LACAZ(1), Clarisse ZAITZ(2), Ligia Rangel B. RUIZ(2), Valifia Maria de SOUZA(2), Ana Regina Alencar SANTOS(2), Laura Hitomi MURAMATU(2), Natalina Takahashi de MELO(I), Elisabeth Maria HEINS-VACCARI(l), Giovana Leticia HERNANDEZ-ARRIAGADA(l) & Roseli Santos de FREITAS-LETE(1)

(1) Laborat6rio de Micologia M6dica, Instituto de Medicina Tropical de Sao Paulo and LUND do Hospital da Clinicas da Faculdade de Medicina da Universidade de SAo Paulo. (2) CMca Dermatol6gica, Faculdade de Ciencias M6dicas, Santa Casa de Miseric6rdia de Slo Paulo - Setor de Dermatologia Infecciosa e Tropical.

Correspondence to: Carlos da Silva Lacaz, Instiruto de Medicina Tropical de Sio Paulo, Laborat6rio de Micologia M6dica. Av. Dr. En6as de Carvalho Aguiar 50OT6rreo, 05403-000 SAo Paulo, SP, Brasil. Phone: 55 11 30667443; FAX 55 11 8523622; E-mail: valacaz@usp.br

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