A Case of Relapsed Chromoblastomycosis Due to Fonsecaea monophora: Antifungal Susceptibility and Phylogenetic Analysis

Abstract

Chromoblastomycosis is a chronic cutaneous and subcutaneous mycosis. The management of this infection continues to be challenging because there is no consensus on the therapeutic regimen. We report here a case of a 69-year-old male patient with cauliflower-like lesions on his left leg and foot. He had already been treated with itraconazole at a dose of 200 mg/day for 5 months, with mycological cure for all the affected areas. However, the lesions relapsed at both sites, and treatment with itraconazole was resumed at the dose previously used. Initially, direct mycological examination, cultural, and microculture slide observation were performed. Afterward, sequencing of the ITS1-5.8S rDNA-ITS2 region of the fungal DNA and evaluation of its susceptibility to antifungal agents alone and in combination were performed. In direct mycological examination, the presence of sclerotic cells was verified, and the fungus was identified as Fonsecaea based on cultural and microscopic examinations. Identification as Fonsecaea monophora was confirmed after sequencing of the ITS region and phylogenetic analysis. The isolate was susceptible to itraconazole and terbinafine. The combinations of amphotericin B and terbinafine and terbinafine and voriconazole were synergistic. The use of drugs for which the causative agent is susceptible to singly or in combination may be an alternative for the treatment of mycosis. Furthermore, the identification of the agent by molecular techniques is important for epidemiological purposes. To the best of our knowledge, this is the first case of relapsed chromoblastomycosis caused by F. monophora in Brazil.

In vitro susceptibility of chromoblastomycosis agents to five antifungal drugs and to the combination of terbinafine and amphotericin B

“…To date, the drugs presenting better results in the treatment are ITZ and TRB . The in vitro results obtained in this study confirms this information, where TRB and ITZ showed the lowest MICs for the majority of the isolates tested.…”

“…In this sense, the combined use of drugs can be an effective alternative, potentiating the action of the drugs and allowing the utilisation of reduced doses, minimising adverse effects . The combination of TRB and ITZ, often used in the clinic, was not synergic in in vitro assays, whereas TRB and AMB combination was synergistic for all genera, with the exception of E. spinifera , reinforcing results found in the literature …”

Chromoblastomycosis in a Diabetic Patient Without a History of Trauma

“…2,11 Chemotherapy options for CBM include various drugs such as ITZ, terbinafine (TBF), posaconazole, voriconazole, amphotericin B, 5-flucytosine, and ketoconazole. 12 Systemic antifungal therapy is validated for all patients whose initial lesions were not diagnosed at early stages nor surgically removed such as in our patient. The different treatment modalities available have not been compared in clinical settings and are mostly based on the successful therapies in reported cases.…”

Differential distribution patterns of Fonsecaea agents of chromoblastomycosis, exemplified by the first case due to F. monophora from Argentina

“…Different antifungal susceptibility profiles may be observed among the different agents. F. monophora was reported to have a better response to treatment compared to F. pedrosoi , although recently resistance was verified in a case of chromoblastomycosis caused by F. monophora [13] , [14] . Therapy may depend on the etiological agent, size of the lesions, and on the patient’s health status and socio-economic parameters.…”