A case of chromomycosis treated by a combination of cryotherapy, shaving, oral 5-fluorocytosine, and oral amphotericin B

Chromoblastomycosis: A Case Series and Literature Review

Chromoblastomycosis is a subcutaneous mycosis caused by a variety of dematiaceous fungi. Fonsecaea (F.) pedrosoi is the most common causative agent. Majority of cases have been reported from tropical and subtropical regions with rural and agricultural background. It is a chronic disease with low incidence of complications but is very refractory to therapies. This is a case series of 22 cases of chromoblastomycosis from two health-care facilities in India. Information regarding the history, clinical presentations, diagnostic methods, therapy, and outcome of treatment were retrieved. Preponderance was seen among the males and in the age group of 41-60 years. Manual and agricultural laborers were commonly affected. Lower extremities were the most common sites affected. Morphological patterns like verrucous plaque, psoriasiform plaque, and verrucous nodules were seen. Direct microscopy with potassium hydroxide (KOH) mount was positive in all the cases. Histopathology in all cases displayed suppurative granulomatous inflammation with pigmented fungal cells. Fungal culture was positive in 10 cases with F. pedrosoi being the commonest agent. Antifungal treatment alone was instituted in 10 cases, cryotherapy along with antifungal therapy was given in 9 cases, and surgical excision was done in 3 cases. Complete clinical cure was achieved in seven cases. Chromoblastomycosis is characterized by chronicity, diverse clinical presentations, and therapeutic recalcitrance. Direct KOH mount of the black dots forms an important bedside tool in the diagnosis. Long-term antifungal therapy along with adjuvant cryotherapy may be the best option for the management.

New possibilities for chromoblastomycosis and phaeohyphomycosis treatment: identification of two compounds from the MMV Pathogen Box® that present synergism with itraconazole

BACKGROUND

Black fungi of the Herpotrichiellaceae family are agents of chromoblastomycosis and phaeohyphomycosis. There are few therapeutic options for these infections and it is common to associate antifungal drugs in their treatment.

OBJECTIVES

To investigate the Medicines for Malaria Venture (MMV) Pathogen Box^® for possible compounds presenting synergism with antifungal drugs used to treat black fungal infections.

METHODS

An initial screening of the Pathogen Box^® compounds was performed in combination with itraconazole or terbinafine at sub-inhibitory concentrations against Fonsecaea pedrosoi. Hits were further tested against eight Herpotrichiellaceae using the checkerboard method.

FINDINGS

No synergism was observed with terbinafine. MMV687273 (SQ109) and MMV688415 showed synergism with itraconazole against F. pedrosoi. Synergism of these compounds was confirmed with some black fungi by the checkerboard method. SQ109 and itraconazole presented synergism for Exophiala dermatitidis, F. pedrosoi, F. monophora and F. nubica, with fungicidal activity for F. pedrosoi and F. monophora. MMV688415 presented synergism with itraconazole only for F. pedrosoi, with fungicidal activity. The synergic compounds had high selectivity index values when combined with itraconazole.

MAIN CONCLUSIONS

These compounds in combination, particularly SQ109, are promising candidates to treat Fonsecaea spp. and E. dermatitidis infections, which account for most cases of chromoblastomycosis and phaeohyphomycosis.

Identifying novel drugs with new modes of action for neglected tropical fungal skin diseases (fungal skinNTDs) using an Open Source Drug discovery approach

INTRODUCTION

The three fungal skin neglected tropical diseases (NTD) mycetoma, chromoblastomycosis and sporotrichosis currently lack prioritization and support to establish drug discovery programs in search for novel treatment options. This has made the efforts to identify novel drugs for these skinNTDs fragmented.

AREAS COVERED

To help escalate the discovery of novel drugs to treat these fungal skinNTDs, the authors have prepared an overview of the compounds with activity against fungal skinNTDs by analyzing data from individual drug discovery studies including those performed on the Medicines for Malaria Venture (MMV) open access boxes.

EXPERT OPINION

The authors were unable to identify studies in which causative agents of all three skinNTDs were included, indicating that an integrated approach is currently lacking. From the currently available data, the azoles and iodoquinol were the only compounds with activity against causative agents from the three different fungal skinNTDs. Fungal melanin inhibition enhanced the activity of antifungal agents. For mycetoma, the fenarimols, aminothiazoles and benzimidazole carbamates are currently being investigated in the MycetOS initiative. To come to a more integrated approach to identify drugs active against all three fungal skinNTDs, compounds made in the MycetOS initiative could also be explored for chromoblastomycosis and sporotrichosis.

Molecular identification and antifungal susceptibility profiles of clinical strains of Fonsecaea spp. isolated from patients with chromoblastomycosis in Rio de Janeiro, Brazil

BACKGROUND

Chromoblastomycosis (CBM) is a difficult-to-treat chronic subcutaneous mycosis. In Brazil, the main agent of this disease is Fonsecaea pedrosoi, which is phenotypically very similar to other Fonsecaea species, differing only genetically. The correct species identification is relevant since different species may differ in their epidemiologic aspects, clinical presentation, and treatment response.

METHODOLOGY/PRINCIPAL FINDINGS

Partial sequencing of the internal transcribed spacer (ITS) was used to identify twenty clinical isolates of Fonsecaea spp. Their in vitro antifungal susceptibility was determined using the broth microdilution method, according to the M38-A2 protocol. Amphotericin B (AMB), flucytosine (5FC), terbinafine (TRB), fluconazole (FLC), itraconazole (ITC), ketoconazole (KTC), posaconazole (POS), voriconazole (VRC), ravuconazole (RVC), caspofungin (CAS), and micafungin (MFG) were tested. The association between ITC/TRB, AMB/5FC, and ITC/CAS was studied by the checkerboard method to check synergism. The available patients' data were correlated with the obtained laboratory results. Fonsecaea monophora (n = 10), F. pedrosoi (n = 5), and F. nubica (n = 5) were identified as CBM' agents in the study. TRB and VRC were the drugs with the best in vitro activity with minimal inhibitory concentrations (MIC) lower than 0.25 mg/L. On the other hand, FLC, 5FC, AMB, and MFG showed high MICs. The AMB/5FC combination was synergistic for three F. monophora strains while the others were indifferent. Patients had moderate or severe CBM, and ITC therapy was not sufficient for complete cure in most of the cases, requiring adjuvant surgical approaches.

CONCLUSIONS/SIGNIFICANCE

F. monophora, the second most frequent Fonsecaea species in South America, predominated in patients raised and born in Rio de Janeiro, Brazil, without cerebral involvement in these cases. TRB, VRC, and the AMB/5FC combination should be further investigated as a treatment option for CBM.

Chromoblastomycosis as an endemic disease in temperate Europe: first confirmed case and review of the literature

This study reports a case of a 56-year-old white male, retired coal-miner, diagnosed with chromoblastomycosis lasting 20 years. The infection site was the burnt skin of the back. For many years the patient had not undertaken any treatment believing that the lesion had been a burn scar. A gradual increase in lesion size prompted the patient to start therapy. The diagnosis was made by histopathological examination and mycological culture. Identification of the causative agent at the species level was achieved by sequence analysis of the internal transcribed spacer (ITS) region and D1/D2 domains of the 26S rDNA. To our knowledge, this is the first documented case of chromoblastomycosis caused by Fonsecaea monophora in temperate Europe, outside the endemic area for the disease. This finding is highly significant for understanding the routes of infection of chromoblastomycosis and radically revises the traditional view of the natural ecology of the etiological agents of the disease.

Putative role of an ABC transporter in Fonsecaea pedrosoi multidrug resistance

Fonsecaea pedrosoi, a dematiaceous fungus, is the main agent responsible for chromoblastomycosis, a chronic and progressive mycosis of the skin and subcutaneous tissues. This disease can cause different types of lesions depending on the immune status of the host. Its treatment is complicated by the toxicity of available antifungal agents as well as drug resistance. In this work, an ATP-binding cassette (ABC) transporter in this fungus was characterised, with the degree of expression related to the drug resistance of two strains (a patient isolated strain and a laboratory strain). A 150 kDa protein was detected by western blotting. The ATPase activity of membrane preparations was also evaluated. The F. pedrosoi transporter appears to behave like Pdr5p, a well-studied multidrug resistance transporter in Saccharomyces cerevisiae with the ability to hydrolyse different triphosphate nucleotides, as well as its response to classical inhibitors tested. Finally, a reverse transcription polymerase chain reaction (RT-PCR) approach was used and a 400 bp product was detected, corresponding to the highly conserved ATP-binding domain of ABC transporters. We suggest that an ABC transporter must be involved in F. pedrosoi multidrug resistance, and a complete understanding of this protein could bring an important contribution to antifungal treatment of this disease.

Antifungal therapy in an athymic murine model of chromoblastomycosis by Fonsecaea pedrosoi

We have compared the efficacy of terbinafine (TRB) and itraconazole (ITZ), the recommended drugs for the treatment of chromoblastomycosis, with that of posaconazole (PSC) and voriconazole (VRC) in athymic mice infected with the fungus Fonsecaea pedrosoi. Three weeks after challenge, mice were treated for 4 months with PSC at 10 or 20 mg/kg of body weight/day, with VRC at 10 or 20 mg/kg/day, with ITZ at 25 or 50 mg/kg/day, or with TRB at 150 or 250 mg/kg/day. The progress of the infection was evaluated by measuring the size of the lesions, by histopathological studies, and by cultures of the excised tissue. The two doses of PSC followed by the highest doses of ITZ and TRB showed the best results while VRC did not show efficacy. PSC could be an alternative in the treatment of chromoblastomycosis.

[Chromomycosis: report of a case with unusual topography]

BACKGROUND

Chromomycosis is a subcutaneous mycosis caused by dematiaceous fungi. It is characterized by the presence of nodules, verrucous and atrophic lesions, and is prevalent in tropical and subtropical areas. Mexico ranks third among the subcutaneous mycoses, mainly affecting the lower limbs. The verrucous lesions are the most common clinical presentation.

AIMS

We present a case of chromomycosis located in the helix and the left earlobe in a 29 year-old male, with unusual morphology and topography.

METHOD

Samples from the affected ear were taken for direct examination, and cultured in Sabouraud dextrose agar and mycobiotic agar.

RESULTS

Fumagoid cells were found when examining the lesion scrapings under direct microscopic examination. The Sabouraud dextrose agar and mycobiotic agar developed a colony of black fungus, which in the microscopic study was identified as Fonsecaea pedrosoi. The definitive diagnosis was chromomycosis, a pathology that was treated with itraconazole 200mg daily for 10 weeks, with a complete resolution of the dermatosis.

CONCLUSIONS

This is a case of chromomycosis with unusual clinical features, with an appropriate response to treatment with itraconazole.

TGF-beta plasma levels in chromoblastomycosis patients during itraconazole treatment

BACKGROUND

Chromoblastomycosis (CBM) is a dermal mycosis. The disease evolves to a chronic state, presenting a suppurative granulomatous dermatitis, combined with variable dermal fibrosis. Pathogenesis of the inflammation and tissue repair in CBM are poorly understood.

AIM

To quantify Transforming Growth Factor-beta (TGF-beta) plasma levels of CBM patients during itraconazole (ITZ) treatment.

METHODS

Blood plasma of 12 CBM patients was subjected to TGF-beta titration with ELISA at 0, 3, 6 and 12months of 200mg per day of ITZ therapy, and correlated with the clinical aspects. Plasma of 12 healthy individuals were used for control.

RESULTS

CBM patients present high plasma levels of TGF-beta (7.016+/-1988pg/ml), decreasing after 03months (4.625+/-645pg/ml) of ITZ treatment, which correlates with a rapid clinical improvement. However, after 6 (6.566+/-777pg/ml) and 12months (6.908+/-776) of treatment, TGF-beta levels increase to almost the same levels observed before treatment, which is related to a slow clinical improvement, fungal persistence on the lesion, and fibrotic scars.

CONCLUSION

TGF-beta plasma levels are high in CBM patients. Fungal destruction by ITZ correlates with TGF-beta downregulation, but tissue remodeling and fungal persistence probably raises its levels again, interfering with cellular immune responses.

Treatment of chromoblastomycosis with terbinafine: A report of four cases

This report is about four cases of chromoblastomycosis confirmed by direct examination, histopathology and cultures. The duration of disease infection varied from 5 to 12 years. By culture, Cladosporium carrionii was isolated in two cases and Fonsecaea pedrosoi in the other two cases. Terbinafine 0.25 g twice daily for 1 month and 0.25 g once daily for maintenance therapy were given to three patients. Terbinafine 0.25 g once daily was given to one patient. After 4-8 months of therapy, all cases were cured without relapse when followed up for 6 months. The total dosage of terbinafine was 37.5-60 g. No relevant side effects showed during treatment.

Beneficial effects of HIV peptidase inhibitors on Fonsecaea pedrosoi: promising compounds to arrest key fungal biological processes and virulence

BACKGROUND

Fonsecaea pedrosoi is the principal etiologic agent of chromoblastomycosis, a fungal disease whose pathogenic events are poorly understood. Current therapy for chromoblastomycosis is suboptimal due to toxicity of the available therapeutic agents and the emergence of drug resistance. Compounding these problems is the fact that endemic countries and regions are economically poor.

PURPOSE AND PRINCIPAL FINDINGS

In the present work, we have investigated the effect of human immunodeficiency virus (HIV) peptidase inhibitors (PIs) on the F. pedrosoi conidial secreted peptidase, growth, ultrastructure and interaction with different mammalian cells. All the PIs impaired the acidic conidial-derived peptidase activity in a dose-dependent fashion, in which nelfinavir produced the best inhibitory effect. F. pedrosoi growth was also significantly reduced upon exposure to PIs, especially nelfinavir and saquinavir. PIs treatment caused profound changes in the conidial ultrastructure as shown by transmission electron microscopy, including invaginations in the cytoplasmic membrane, disorder and detachment of the cell wall, enlargement of fungi cytoplasmic vacuoles, and abnormal cell division. The synergistic action on growth ability between nelfinavir and amphotericin B, when both were used at sub-inhibitory concentrations, was also observed. PIs reduced the adhesion and endocytic indexes during the interaction between conidia and epithelial cells (CHO), fibroblasts or macrophages, in a cell type-dependent manner. Moreover, PIs interfered with the conidia into mycelia transformation when in contact with CHO and with the susceptibility killing by macrophage cells.

CONCLUSIONS/SIGNIFICANCE

Overall, by providing the first evidence that HIV PIs directly affects F. pedrosoi development and virulence, these data add new insights on the wide-spectrum efficacy of HIV PIs, further arguing for the potential chemotherapeutic targets for aspartyl-type peptidase produced by this human pathogen.

Biology and pathogenesis of Fonsecaea pedrosoi, the major etiologic agent of chromoblastomycosis

Fonsecaea pedrosoi is the principal etiologic agent of chromoblastomycosis, a fungal disease whose pathogenic events are poorly understood. Treatment of the disease presents poor effectiveness and serious side effects. The disease is epidemiologically important in several regions, which has stimulated studies focused on the biology and pathogenic potential of its major causative agent. In this review, we summarize the current knowledge on the biological aspects of F. pedrosoi, including cell differentiation and pathogenic mechanisms during the interaction of fungi with different hosts' elements.

Tropical dermatology: fungal tropical diseases

Fungal infections are common in tropical countries and can have an important impact on public health. Lobomycosis is a common fungal infection in the tropical rain forest of South America, and paracoccidioidomycosis (South American blastomycosis) is a widespread and sometimes severe illness. Penicilliosis marneffei is an opportunistic infection of AIDS patients in southeast Asia. Chromoblastomycosis and mycetomas are causes of morbidity around the world. Sporotrichosis is a worldwide subcutaneous mycosis with a high incidence in tropical countries and is an important illness in immunocompromised patients. Rhinosporidiosis was classed as a fungal infection but is now considered a protistan parasite that belongs to the class Mesomycetozoea. It is included in this review because of its historical classification. In the past, most of these mycoses were restricted to specific geographic areas and natural reservoirs. There are, however, situations in which people from other regions come in contact with the pathogen. A common situation involves an accidental contamination of a traveler or worker who has contact with a tropical mycosis. Even minor trauma to the skin surface or inhalation of the fungal conidia can infect the patient. Thus recognition of the clinical symptoms and the dermatologic findings of the diseases, as well as the geographic distribution of the pathogens, can be critical in diagnosis of the tropical mycoses. This review discusses some of the more common tropical subcutaneous and systemic mycoses, as well as their signs, symptoms, methods of diagnosis, and therapies.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be able to recognize the clinical and histologic presentations of tropical fungal diseases with cutaneous manifestations and be familiar with the appropriate therapies.

Susceptibility of sequential Fonsecaea pedrosoi isolates from chromoblastomycosis patients to antifungal agents. Antimykotika-Empfindlichkeit von sequenziellen Fonsecaea pedrosoi-Isolaten von Chromoblastomykose-Patienten

Fourteen Fonsecaea pedrosoi isolates from six chromoblastomycosis patients were submitted to susceptibility testing. Some patients were undergoing treatment with itraconazole (ITZ) and/or cryosurgery with liquid nitrogen. The antifungal agents amphotericin B (AMB), ITZ, fluconazole (FCZ), ketoconazole (KCZ), 5-fluorocytosine (5-FC), and terbinafine (TBF) were tested. AMB and FCZ showed less activity for all isolates. The most active agents were KCZ and TBF. Sequentially isolates from four patients presented ITZ minimal inhibitory concentration (MIC) higher than the previous ones; for two of these patients, response to therapy with this agent was not observed. These results suggest development of microbiologic resistance to ITZ in four instances, two of them coinciding with lack of clinical response to this drug.

A monoclonal antibody to glucosylceramide inhibits the growth of Fonsecaea pedrosoi and enhances the antifungal action of mouse macrophages

Fungal glucosylceramides (GlcCer) are conserved lipid components in a large variety of pathogenic and non-pathogenic fungal species, but their biological functions are still unclear. Recent studies demonstrate that GlcCer are immunologically active components inducing the production of antifungal antibodies. In this work, a major GlcCer was purified and characterized from mycelial forms of Fonsecaea pedrosoi, the most frequent causative agent of chromoblastomycosis. As determined by fast atom bombardment mass spectrometry (FAB-MS) analysis, the purified molecule was identified as the conserved structure N-2'-hydroxyhexadecanoyl-1-beta-D-glucopyranosyl-9-methyl-4,8-sphingadienine. A monoclonal antibody (Mab) against this structure was used in indirect immunofluorescence with the different morphological stages of F. pedrosoi. Only the surface of young dividing cells was recognized by the antibody. Treatment of F. pedrosoi conidia with the Mab against GlcCer resulted in a clear reduction in fungal growth. In addition, the Mab also enhanced phagocytosis and killing of F. pedrosoi by murine cells. These results suggest that, in F. pedrosoi, GlcCer seem to be cell wall components targeted by antifungal antibodies that directly inhibit fungal development and also enhance macrophage function, supporting the use of monoclonal antibodies to GlcCer as potential tools in antifungal immunotherapy.

Phosphatase activity on the cell wall of Fonsecaea pedrosoi

The activity of a phosphatase was characterized in intact mycelial forms of Fonsecaea pedrosoi, a pathogenic fungus that causes chromoblastomycosis. At pH 5.5, this fungus hydrolyzed p-nitrophenylphosphate (p-NPP) to p-nitrophenol (p-NP) at a rate of 12.78 +/- 0.53 nmol p-NP per h per mg hyphal dry weight. The values of Vmax and apparent Km for p-NPP hydrolyses were measured as 17.89 +/- 0.92 nmol p-NP per h per mg hyphal dry weight and 1.57 +/- 0.26 mmol/l, respectively. This activity was inhibited at increased pH, a finding compatible with an acid phosphatase. The enzymatic activity was strongly inhibited by classical inhibitors of acid phosphatases such as sodium orthovanadate (Ki = 4.23 micromol/l), sodium molybdate (Ki = 7.53 micromol/l) and sodium fluoride (Ki = 126.78 micromol/l) in a dose-dependent manner. Levamizole (1 mmol/l) and sodium tartrate (10 mmol/l), had no effect on the enzyme activity. Cytochemical localization of the acid phosphatase showed electrondense cerium phosphate deposits on the cell wall, as visualized by transmission electron microscopy. Phosphatase activity in F. pedrosoi seems to be associated with parasitism, as sclerotic cells, which are the fungal forms mainly detected in chromoblastomycosis lesions, showed much higher activities than conidia and mycelia did. A strain of F. pedrosoi recently isolated from a human case of chromoblastomycosis also showed increased enzyme activity, suggesting that the expression of surface phosphatases may be stimulated by interaction with the host.

New and re-emerging cutaneous infectious diseases in Latin America and other geographic areas

Due to environmental factors and inadequate public health measures in many developing countries, new tropical infections, as well as infections that were previously isolated to remote locales, are becoming more prevalent in several areas of Latin America. This article discusses some tropical infections and infestations with predominantly cutaneous manifestations. Previously uncommon diseases such as gnathostomiasis, mycobacteria ulcerans infection, paederus dermatitis, Balamuthia mandrillaris infection, and human T-lymphotrophic virus 1 dermatitis are increasingly being reported. Well-known tropical infections such as bartonellosis, leishmaniasis, chromomycosis, larva migrans, and larva currens are also becoming more prevalent. On the other hand, the incidence of Hansen's disease, the quintessential tropical infection, is dwindling all over the globe thanks to a highly effective eradication campaign launched by the World Health Organization. Because of increased immigration and tourist travel, the number of cases of these diseases in the United States may escalate.