Chromoblastomycosis in the Clinical Practice

Chromoblastomycosis Caused by Fonsecaea monophora Mimicking Lichen Planus

Chromoblastomycosis is a rare fungal infection acquired by traumatic inoculation of pigmented fungi from an environmental source. The polymorphic presentation of chromoblastomycosis may mimic other dermatologic conditions, leading to delays in diagnosis. Thus, histopathology is critical in identifying the presence of fungi and confirming the diagnosis. We present a case of chromoblastomycosis caused by the organism Fonsecaea monophora mimicking a lesion of lichen planus to highlight the importance of histopathology in the diagnosis of this condition.

Chromoblastomycosis in the Amazon region, Brazil, caused by Fonsecaea pedrosoi, Fonsecaea nubica, and Rhinocladiella similis: Clinicopathology, susceptibility, and molecular identification

Chromoblastomycosis is a chronic subcutaneous disease caused by human contact with melanized fungi occurring mainly in tropical and subtropical zones worldwide. This study assessed 12 patients with chromoblastomycosis from Rondônia, Brazil, Amazon region. In sum, 83.3% were men, 41.6% were from Monte Negro city, median age was 52.9 years, and median time to disease progression was 12.2 years. Lesions were located on the lower limbs (75%), and verruciform was prevalent form (66.6%). After 3 years of treatment with itraconazole, two patients were considered cured. The etiological agents were identified by the molecular sequence of the ribosomal internal transcribed spacer ITS1, 5.8S, and ITS2 region and β-tubulin genes. Eight strains were identified as Fonsecaea pedrosoi, two were F. nubica, and two were Rhinocladiella similis. The antifungal activity of five drugs was evaluated, and the most active drug was terbinafine (range minimal inhibitory concentration [MIC] 0.015-0.12 μg/ml), itraconazole (range MIC 0.03-0.5 μg/ml) and voriconazole (range MIC 0.06-0.5 μg/ml). The highest MIC was 5-fluorocytosine (range MIC 2-32 μg/ml), and amphotericin B (range MIC 0.25-2 μg/ml). In conclusion, the present study expanded the epidemiological disease database and described for the first time F. nubica and R. similis as chromoblastomycosis agents in the Brazilian Amazon region. Our results confirmed the importance of using molecular methods to identify the melanized fungi and stimulate the recognition of the disease in other places where no cases have been reported.

Increased virulence of albino mutant of Fonsecaea monophora in Galleria mellonella

Fonsecaea monophora has been the predominant pathogen of chromoblastomycosis in Southern China, but its pathogenic mechanism remains unclear. New models are needed to study this infection. In the current study, we examined the role of melanin on the pathogenicity of F. monophora in Galleria mellonella model using melanin and albino strain. Interestingly, the albino mutant strain displayed higher pathogenicity compared to the melanin stain and restoration of melanin of albino mutant could reverse the pathogenicity. Histopathology showed that inflammatory nodules were bigger than that infected with albino cells, which suggested that melanized cells could trigger a robust cellular immune response of G. mellonella than albino cells. The activated immune response in G. mellonella induced by melanized cells might explain the decreased virulence of melanized cells in larvae model. While further study was needed to gain full insights into the molecular immunological mechanism in G. mellonella activated by melanin.

Exophiala psychrophila: A new agent of chromoblastomycosis

Chromoblastomycosis is a chronic cutaneous and subcutaneous mycosis, is caused by dematiaceous fungi, the most frequently implicated are Fonsecaea, Phialophora, Cladophialophora, Rhinocladiella and Exophiala.

We report a woman who was treated before with mycological cure, but she experience a relapse requiring treatment again. Direct microscopic examination and skin biopsy with culture were necessary to identify a Exophiala psychrophila, and for our knowledge this is the first case reported.

Chromoblastomycosis

Chromoblastomycosis (CBM), also known as chromomycosis, is one of the most prevalent implantation fungal infections, being the most common of the gamut of mycoses caused by melanized or brown-pigmented fungi. CBM is mainly a tropical or subtropical disease that may affect individuals with certain risk factors around the world. The following characteristics are associated with this disease: (i) traumatic inoculation by implantation from an environmental source, leading to an initial cutaneous lesion at the inoculation site; (ii) chronic and progressive cutaneous and subcutaneous tissular involvement associated with fibrotic and granulomatous reactions associated with microabscesses and often with tissue proliferation; (iii) a nonprotective T helper type 2 (Th2) immune response with ineffective humoral involvement; and (iv) the presence of muriform (sclerotic) cells embedded in the affected tissue. CBM lesions are clinically polymorphic and are commonly misdiagnosed as various other infectious and noninfectious diseases. In its more severe clinical forms, CBM may cause an incapacity for labor due to fibrotic sequelae and also due to a series of clinical complications, and if not recognized at an early stage, this disease can be refractory to antifungal therapy.

Neglected endemic mycoses

Fungi often infect mammalian hosts via the respiratory route, but traumatic transcutaneous implantation is also an important source of infections. Environmental exposure to spores of pathogenic fungi can result in subclinical and unrecognised syndromes, allergic manifestations, and even overt disease. After traumatic cutaneous inoculation, several fungi can cause neglected mycoses such as sporotrichosis, chromoblastomycosis, mycetoma, entomophthoramycosis, and lacaziosis. Most of these diseases have a subacute to chronic course and they can become recalcitrant to therapy and lead to physical disabilities, including inability to work, physical deformities, and amputations. For many years, paracoccidioidomycosis was considered the most prevalent endemic systemic mycosis in the Americas, but this situation might be changing with recognition of the worldwide presence of Histoplasma capsulatum. Both paracoccidioidomycosis and histoplasmosis can mimic several infectious and non-infectious medical conditions and lead to death if not recognised early and treated. Cutaneous implantation and systemic mycoses are neglected diseases that affect millions of individuals worldwide, especially in low-income countries where their management is suboptimum because challenges in diagnosis and therapeutic options are substantial issues.

1,10-Phenanthroline-5,6-Dione-Based Compounds Are Effective in Disturbing Crucial Physiological Events of Phialophora verrucosa

Phialophora verrucosa is a dematiaceous fungus able to cause chromoblastomycosis, phaeohyphomycosis and mycetoma. All these fungal diseases are extremely difficult to treat and often refractory to the current therapeutic approaches. Therefore, there is an urgent necessity to develop new antifungal agents to combat these mycoses. In this context, the aim of the present work was to investigate the effect of 1,10-phenanthroline-5,6-dione (phendione) and its metal-based derivatives [Ag(phendione)₂]ClO₄ = ([Ag(phendione)₂]⁺) and [Cu(phendione)₃](ClO₄)₂.4H₂O = ([Cu(phendione)₃]²⁺) on crucial physiological events of P. verrucosa conidial cells. Using the CLSI protocol, we have shown that phendione, [Ag(phendione)₂]⁺ and [Cu(phendione)₃]²⁺ were able to inhibit fungal proliferation, presenting MIC/IC₅₀ values of 12.0/7.0, 4.0/2.4, and 5.0/1.8 μM, respectively. [Cu(phendione)₃]²⁺ had fungicidal action and when combined with amphotericin B, both at sub-MIC (½ × MIC) concentrations, significantly reduced (~40%) the fungal growth. Cell morphology changes inflicted by phendione and its metal-based derivatives was corroborated by scanning electron microscopy, which revealed irreversible ultrastructural changes like surface invaginations, cell disruption and shrinkages. Furthermore, [Cu(phendione)₃]²⁺ and [Ag(phendione)₂]⁺ were able to inhibit metallopeptidase activity secreted by P. verrucosa conidia by approximately 85 and 40%, respectively. Ergosterol content was reduced (~50%) after the treatment of P. verrucosa conidial cells with both phendione and [Ag(phendione)₂]⁺. To different degrees, all of the test compounds were able to disturb the P. verrucosa conidia-into-mycelia transformation. Phendione and its Ag⁺ and Cu²⁺ complexes may represent a promising new group of antimicrobial agents effective at inhibiting P. verrucosa growth and morphogenesis.

CHROMOBLASTOMYCOSIS: A NEGLECTED TROPICAL DISEASE

Chromoblastomycosis (CMB) is a chronic fungal infection of the skin and the subcutaneous tissue caused by a transcutaneous traumatic inoculation of a specific group of dematiaceous fungi occurring mainly in tropical and subtropical zones worldwide. If not diagnosed at early stages, patients with CBM require long term therapy with systemic antifungals, sometimes associated with physical methods. Unlike other neglected endemic mycoses, comparative clinical trials have not been performed for this disease. Nowadays, therapy is based on a few open trials and on expert opinion. Itraconazole either as monotherapy or associated with other drugs, or with physical methods, is widely used. Recently, photodynamic therapy has been successfully employed in combination with antifungals in patients presenting with CBM. In the present revision the most used therapeutic options against CBM are reviewed as well as the several factors that may have impact on the patient's outcome.

Chromoblastomycosis: an exuberant case

Chromoblastomycosis is a chronic subcutaneous mycotic infection caused by dematiaceous saprophytic moulds. The most frequently isolated agent is Fonsecae pedrosoi. This article reports a case of a man from the Amazon region in Northern Brazil who presented with a lesion of 12 months' duration, which gradually increased in size until covering the majority of his right leg. A successful treatment with itraconazole was performed.