Alternate week and combination itraconazole and terbinafine therapy for chromoblastomycosis caused by Fonsecaea pedrosoi in Brazil

Effectiveness and safety of oral terbinafine for dermatophyte distal subungual onychomycosis

INTRODUCTION

Terbinafine has been a cornerstone in dermatophyte infection treatment. Despite its global efficacy, the emergence of terbinafine resistance raises concerns, requiring ongoing vigilance.

AREAS COVERED

This paper focuses on evaluating the efficacy and safety of terbinafine in treating dermatophyte toenail infections. Continuous and pulse therapies, with a 24-week continuous regimen and a higher dosage of 500 mg/day have demonstrated superior efficacy to the FDA approved regimen of 250 mg/day x 12 weeks. Pulse therapies, though showing comparable effectiveness, present debates with regards to their efficacy as conflicting findings have been reported. Safety concerns encompass hepatotoxicity, gastrointestinal, cutaneous, neurologic, hematologic and immune adverse-effects, and possible drug interactions, suggesting the need for ongoing monitoring.

EXPERT OPINION

Terbinafine efficacy depends on dosage, duration, and resistance patterns. Continuous therapy for 24 weeks and a dosage of 500 mg/day may enhance outcomes, but safety considerations and resistance necessitate individualized approaches. Alternatives, including topical agents and alternative antifungals, are to be considered for resistant cases. Understanding the interplay between treatment parameters, adverse effects, and resistance mechanisms is critical for optimizing therapeutic efficacy while mitigating resistance risks. Patient education and adherence are vital for early detection and management of adverse effects and resistance, contributing to tailored and effective treatments.

Combatting antifungal resistance: Paradigm shift in the diagnosis and management of onychomycosis and dermatomycosis

Antifungal resistance has become prevalent worldwide. Understanding the factors involved in spread of resistance allows the formulation of strategies to slow resistance development and likewise identify solutions for the treatment of highly recalcitrant fungal infections. To investigate the recent explosion of resistant strains, a literature review was performed focusing on four main areas: mechanisms of resistance to antifungal agents, diagnosis of superficial fungal infections, management, and stewardship. The use of traditional diagnostic tools such as culture, KOH analysis and minimum inhibitory concentration values on treatment were investigated and compared to the newer techniques such as molecular methods including whole genome sequencing, and polymerase chain reaction. The management of terbinafine-resistant strains is discussed. We have emphasized the need for antifungal stewardship including increasing surveillance for resistant infection.

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.

Inhibition of Melanization by Kojic Acid Promotes Cell Wall Disruption of the Human Pathogenic Fungus Fonsecaea sp

Chromoblastomycosis (CBM) is a chronic human subcutaneous mycosis caused by various aetiologic agents. CBM does not have an established treatment but may be managed using antifungal agents, surgical removal of the lesions, or cryotherapy. Kojic acid (KA), a known tyrosinase inhibitor with a variety of biological actions, including fungistatic action against the fungus Cryptococcus neoformans, mediated by inhibiting melanin production, seems to be an alternative to improve the treatment of CBM. The aim of the present study was to analyze the action of KA against the pathogenic fungus Fonsecaea sp., an aetiological agent of CBM. The fungal culture was incubated with KA, and the amount of melanin was assessed, followed by cytochemical detection. Subsequently, the samples were analyzed by light microscopy, transmission and scanning electron microscopy. Culture analysis revealed that 100 g/mL KA significantly decreased the melanization of the fungus and the exocytosis of melanin into the culture supernatant. Additionally, KA induced less growth of biofilm formation and intense disruption of the cell wall, and decreased the number of melanin-containing vesicles in the culture supernatant. Finally, KA inhibited fungal filamentation in culture and the subsequent phagocytosis process. Thus, KA may be a promising substance to help in the treatment of CBM.

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.

Reviewing the Etiologic Agents, Microbe-Host Relationship, Immune Response, Diagnosis, and Treatment in Chromoblastomycosis

Chromoblastomycosis (CBM) is a neglected human disease, caused by different species of pigmented dematiaceous fungi that cause subcutaneous infections. This disease has been considered an occupational disease, occurring among people working in the field of agriculture, particularly in low-income countries. In 1914, the first case of CBM was described in Brazil, and although efforts have been made, few scientific and technological advances have been made in this area. In the field of fungi and host cell relationship, a very reduced number of antigens were characterized, but available data suggest that ectoantigens bind to the cell membrane of host cells and modulate the phagocytic, immunological, and microbicidal responses of immune cells. Furthermore, antigens cleave extracellular proteins in tissues, allowing fungi to spread. On the contrary, if phagocytic cells are able to present antigens in MHC molecules to T lymphocytes in the presence of costimulation and IL-12, a Th1 immune response will develop and a relative control of the disease will be observed. Despite knowledge of the resistance and susceptibility in CBM, up to now, no effective vaccines have been developed. In the field of chemotherapy, most patients are treated with conventional antifungal drugs, such as itraconazole and terbinafine, but these drugs exhibit limitations, considering that not all patients heal cutaneous lesions. Few advances in treatment have been made so far, but one of the most promising ones is based on the use of immunomodulators, such as imiquimod. Data about a standard treatment are missing in the medical literature; part of it is caused by the existence of a diversity of etiologic agents and clinical forms. The present review summarizes the advances made in the field of CBM related to the diversity of pathogenic species, fungi and host cell relationship, antigens, innate and acquired immunity, clinical forms of CBM, chemotherapy, and diagnosis.

Drug Sensitivity Profile of Fungi Isolated from Onychomycosis Patients and Evaluation of Squalene Epoxidase Mutation in One Terbinafine-Resistant Trichophyton mentagrophytes Species

Background: The resistance to treatment of onychomycosis is increasingly reported. The present study aimed to assess the antifungal activity of itraconazole, terbinafine, luliconazole, and efinaconazole against dermatophytes, molds, and also yeast isolated from patients with onychomycosis. Furthermore, the mechanism of resistance to terbinafine in resistant Trichophyton mentagrophytes species was evaluated using the squalene epoxidase (SQLE) gene sequence. Methods: A total of 71 fungal isolates were collected from 97 patients with suspected onychomycosis. The identification of fungal species was performed using conventional and molecular approaches. In vitro drug susceptibility for itraconazole, terbinafine, luliconazole, and efinaconazole was carried out using the broth microdilution method according to the CLSI-M60 and CLSI-M38 3rd ed., respectively. The SQLE gene of one terbinafine-resistant T. mentagrophytes was amplified using the specific primers. Results: Efinaconazole and luliconazole demonstrated higher effectiveness against all isolates in the study. One mismatch was detected at position 1177, which showed A → C change associated with Phe397Leu amino acid substitution of the SQLE protein in terbinafine-resistant T. mentagrophytes. Conclusion: The occurrence of resistant strains of organisms causing onychomycosis should be considered and evaluated. Furthermore, the identification of amino acid changes responsible for resistance to antifungals is a useful consideration in drug-target interaction.

Combining derivative and synchronous approaches for simultaneous spectrofluorimetric determination of terbinafine and itraconazole

In this study, determination of terbinafine and itraconazole down to biological concentration level has been carried out. The determination is based on increasing the selectivity of the spectrofluorimetric technique by combining both derivative and synchronous spectrofluorometric approaches, which permits successful estimation of terbinafine at 257 nm and itraconazole at 319 nm in the presence of each other at Δλ of 60 nm. International Conference on Harmonization validation guidelines were followed to fully validate the method, and linearity was obtained for the two drugs over the range of 0.1-0.7 µg ml-1 for terbinafine and 0.5-4.0 µg ml-1 for itraconazole. Application of the method was successfully carried out in the commercial tablets with good agreement with the comparison spectrofluorometric methods. As the detection limits were down to 0.013 and 0.1 µg ml-1 and quantitation limits were 0.04 and 0.032 µg ml-1 for terbinafine and itraconazole, respectively; the in vitro determination of terbinafine and itraconazole in spiked plasma samples was applicable. The percentage recoveries in biological samples were 97.17 ± 4.54 and 98.75 ± 2.25 for terbinafine and itraconazole, respectively. Water was used as the optimum diluting solvent in the proposed methodology which adds an eco-friendly merit.

[Management of chromoblastomycosis, a challenge for limited-resource countries such as Madagascar]

INTRODUCTION

Chromoblastomycosis (CBM) is a chronic fungal infection of the skin and subcutaneous tissue caused by dematiaceous fungi. CBM lesions are recalcitrant and extremely difficult to eradicate. We report three cases of CBM with difficulties in therapeutic management.

OBSERVATION

Three men aged 36, 50 and 67 years, all farmers, presented for between three and ten years with hyperkeratotic, scaly plaques with black dots on the right thigh and left leg, respectively. For all patients, mycological examination showed fumagoid cells, all of which were pathognomonic for CBM. PCR identified Fonsecaeanubica in one patient and Cladophialophoracarrionii in two patients. All patients received itraconazole 200mg/day for over 18 months. Two patients required combined therapy with terbinafine for seven months, which improved lesions; however, relapse occurred in one patient during the 5th month of this combined therapy and five months after the end of this treatment in the other. The patient on monotherapy (itraconazole) also presented recurrence of lesions five months after the end of treatment.

DISCUSSION

Itraconazole is the standard therapy for CBM, with cure rates ranging from 15 to 80%. Success with itraconazole after eight to twelve months was reported by several authors. Fonsecaea and Cladophialophora are the most common species found in Madagascar, and while these organisms are susceptible to triazoles in vitro, clinical response is not so clear-cut.

CONCLUSION

Although unavailable in Madagascar, posaconazole and isavoconazole appear to be effective in treating chromoblastomycosis.

Synergistic effect of terbinafine and amphotericin B in killing Fonsecaea nubica in vitro and in vivo

Chromoblastomycosis is a chronic fungal infection. Itraconazole and terbinafine are the most recommended antifungal drugs for chromoblastomycosis, while amphotericin B is not usually recommended. A patient with chromoblastomycosis in our hospital showed poor clinical responses to itraconazole and terbinafine. The fungus isolated from the lesions of this patient was identified as Fonsecaea nubica and numbered zssy0803. In vitro antifungal susceptibilities of F. nubica zssy0803 to terbinafine, amphotericin B, itraconazole, voriconazole and caspofungin were evaluated, as well as the combinations of terbinafine with the other four antifungals. The combined effect of terbinafine and amphotericin B on other 20 clinical F. nubica strains was also evaluated. The minimal inhibitory concentrations of terbinafine, amphotericin B, itraconazole, voriconazole and caspofungin on F. nubica zssy0803 were 0.25 μg/mL, 2 μg/mL, 1 μg/mL, 4 μg/mL and 8 μg/mL, respectively. The combination of terbinafine and amphotericin B showed the lowest fractional inhibitory concentration index of 0.28 to F. nubica zssy0803 in comparison with combinations of terbinafine and the other four antifungal drugs. The combination of terbinafine and amphotericin B was also synergistic for all the other 20 F. nubica strains. Then, the combination of oral terbinafine (500 mg/day) and intralesional injections of amphotericin B (1 mg/mL) was used to treat this patient. After this combined therapy for 25 weeks and terbinafine monotherapy for additional 12 weeks, the patient was cured. These findings indicate for the first time that terbinafine and amphotericin B are synergistic in killing F. nubica both in vitro and in vivo.

Chromoblastomycosis in Taiwan: A report of 30 cases and a review of the literature

Chromoblastomycosis (CBM) is an implantation mycosis characterized by the presence of pigmented muriform cells in tissue. CBM is endemic in Taiwan, but only three formal cases have been reported to date because of underreporting. To describe and update its epidemiologic features, we report a series of 30 cases between 2003 and 2016 at a single medical center. Patients were predominately male (2.75:1). The mean age of onset was 65.9 years, and disease duration ranged from 2 months to 20 years. Diabetes was the most common comorbidity, and extremities were the most frequent sites of involvement. The lesions presented as papuloplaque, verrucous, cicatricial, targetoid, or mixed types. The dermoscopic features were variable, including red dots, white vague areas, black globules, and sand-like patterns. Among 10 Fonsecaea isolates further identified by sequencing the ITS regions of ribosomal DNA, nine were F. monophora and one was F. nubica. All but one patient received either systemic antifungal agents, surgical excision, or both. Surgical excision achieved a higher complete remission rate than the other forms of treatment did.

Evaluation of efficacy and safety of oral terbinafine and itraconazole combination therapy in the management of dermatophytosis

Background: There has been an alarming increase in recalcitrant dermatophytosis in recent years. The standard treatment guidelines no longer seem effective in achieving clearance and results in high failure rates.Objective: To evaluate the efficacy and safety of oral terbinafine and itraconazole combination therapy in the management of dermatophytosis.Methods: Clinically diagnosed and KOH positive patients of tinea corporis/cruris/faciei were randomly divided into three groups and given terbinafine 250 mg, itraconazole 200 mg and a combination of both once daily taken on the same day respectively for 3 weeks. Partial responders at the end of the therapy were given same treatment for additional 3 weeks. Clinical parameters namely itching, erythema, and scaling were evaluated at baseline, 3, 6, and 9 weeks. Adverse effects were noted at the end of therapy.Results: Maximum clinical and mycological cure was achieved in group III (receiving combination therapy) (90%) followed by group II (receiving itraconazole) (50%) and group I (receiving terbinafine) (35%). The combination therapy of oral terbinafine and itraconazole was found to be as safe as monotherapy without any significant adverse effects.Conclusions: The combination of systemic terbinafine and itraconazole therapy may be an effective and safe therapeutic strategy in the management of dermatophytosis.

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: an etiological, epidemiological, clinical, diagnostic, and treatment update

Chromoblastomycosis is a chronic, granulomatous, suppurative mycosis of the skin and subcutaneous tissue caused by traumatic inoculation of dematiaceous fungi of the family Herpotrichiellaceae. The species Fonsecaea pedrosoi and Cladophialophora carrionii are prevalent in regions where the disease is endemic. Chromoblastomycosis lesions are polymorphous: verrucous, nodular, tumoral, plaque-like, and atrophic. It is an occupational disease that predominates in tropical and subtropical regions, but there have been several reports of cases in temperate regions. The disease mainly affects current or former farm workers, mostly males, and often leaving disabling sequelae. This mycosis is still a therapeutic challenge due to frequent recurrence of lesions. Patients with extensive lesions require a combination of pharmacological and physical therapies. The article provides an update of epidemiological, clinical, diagnostic, and therapeutic features.

Combination of Amphotericin B and Terbinafine against Melanized Fungi Associated with Chromoblastomycosis

Our in vitro studies showed that a combination of amphotericin B and terbinafine had synergistic effects against the majority of melanized fungi associated with chromoblastomycosis (CBM) and similar infections, including those with Cladophialophora carrionii, Cladophialophora arxii, Exophialadermatitidis, Exophialaspinifera, Fonsecaea monophora, Fonsecaea nubica, Fonsecaea pedrosoi, and Phialophora verrucosa. This drug combination could provide an option for the treatment of severe or unresponsive cases of CBM, particularly in cases due to species of Fonsecaea and Cladophialophora.

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.

Combining two antifungal agents does not enhance survival of Galleria mellonella larvae infected with Madurella mycetomatis

OBJECTIVE

To determine whether combination therapy would improve therapeutic outcome in eumycetoma caused by Madurella mycetomatis.

METHODS

Survival, colony-forming units (CFU), melanisation and histopathology in M. mycetomatis-infected Galleria mellonella larvae treated with amphotericin B, itraconazole, terbinafine or combinations thereof were determined.

RESULTS

Compared to larvae treated with 5% glucose, enhanced survival was obtained when M. mycetomatis-infected larvae were treated with amphotericin B, but not when they were treated with itraconazole or terbinafine. Combination therapy did not increase survival compared to 5% glucose-treated larvae, itraconazole-treated larvae or terbinafine-treated larvae. Compared to amphotericin B monotreatment, a significant decrease in survival was noted when this therapy was combined with either itraconazole or terbinafine. CFU, melanisation and histopathology did not differ between monotherapy, combination therapy or 5% glucose-treated larvae.

CONCLUSIONS

Combining different classes of antifungal agents did not enhance the survival of M. mycetomatis-infected G. mellonella larvae. Instead of improving the therapeutic outcome, combining either itraconazole or terbinafine with amphotericin B resulted in significantly lower survival rates of infected larvae than amphotericin B monotherapy. This experimental study does not provide support for the use of combined amphotericin B and itraconazole, combined itraconazole and terbinafine or combined terbinafine and amphotericin B and should be confirmed in other animal models.

[Chromomycosis acquired in a non-tropical area: A case report]

BACKGROUND

Chromomycosis, or chromoblastomycosis, is caused by cutaneous inoculation of dematiaceous fungi of telluric or plant origin. It is generally seen in tropical or subtropical zones. Treatment of the condition is known to be complex. Herein we report a case of chromomycosis contracted in a temperate region of Eastern Europe/Central Asia that was effectively treated with oral itraconazole and terbinafine in combination with cryotherapy.

PATIENTS AND METHODS

A 44-year-old immunocompetent male subject consulted for a lesion on the buttocks that he had sustained 16 years earlier, and which, although never previously treated, had only become troublesome within the last few months. The examination revealed a large erythemato-squamous plaque containing a heterogeneous infiltrate. The diagnosis was based upon biopsy, with histological examination revealing sooty mould ; culture of a second sample showed the causative agent to be Fonsecaea pedrosoi. After 30 months of treatment combining oral terbinafine at a very high dose (1000mg/day), topical terbinafine and adjuvant cryotherapy, considerable, though incomplete, improvement was obtained. Finally, combined use of terbinafine (500mg/day) and itraconazole (200mg/day) led to clinical and histological cure.

DISCUSSION

The possibility of acquiring chromomycosis other than in a tropical zone is slight but has nevertheless been described, particularly in Eastern Europe. In our patient, the exact source of contamination is unknown, although it may have been acquired through frequent horse-riding or use of saunas. This case confirms the efficacy of combined itraconazole and terbinafine against this condition, which is usually difficult to treat.

Treatment of Refractory Chromomycosis by Isolated Limb Infusion with Melphalan and Actinomycin D

Background:

Chromomycosis is frequently resistant to systemic and local therapies, and advanced bulky disease can compromise limb function.

Methods:

A man developed extensive chromomycosis of the left arm, refractory to multiple systemic and local treatments. Regional chemotherapy with the isolated limb infusion (ILI) technique using melphalan and actinomycin D markedly reduced disease bulk and greatly improved function of the arm over the next 2 months. Repeat ILI was performed 10 months later, again with good improvement in mobility of the elbow and significant debulking of disease. At the present time, there is some persistent but stable disease, which is controlled by heat therapy with disposable pocket warmers. The patient declined any further systemic therapy.

Conclusion:

ILI rapidly reduced disease bulk, restoring the limb to normal function within a few weeks. Although not curative, ILI could be an effective adjunctive treatment for severe chromomycosis in patients resistant to or intolerant of other therapies.

Black yeasts and their filamentous relatives: principles of pathogenesis and host defense

Among the melanized fungi, the so-called "black yeasts" and their filamentous relatives are particularly significant as agents of severe phaeohyphomycosis, chromoblastomycosis, and mycetoma in humans and animals. The pathogenicity and virulence of these fungi may differ significantly between closely related species. The factors which probably are of significance for pathogenicity include the presence of melanin and carotene, formation of thick cell walls and meristematic growth, presence of yeast-like phases, thermo- and perhaps also osmotolerance, adhesion, hydrophobicity, assimilation of aromatic hydrocarbons, and production of siderophores. Host defense has been shown to rely mainly on the ingestion and elimination of fungal cells by cells of the innate immune system, especially neutrophils and macrophages. However, there is increasing evidence supporting a role of T-cell-mediated immune responses, with increased interleukin-10 (IL-10) and low levels of gamma interferon (IFN-γ) being deleterious during the infection. There are no standardized therapies for treatment. It is therefore important to obtain in vitro susceptibilities of individual patients' fungal isolates in order to provide useful information for selection of appropriate treatment protocols. This article discusses the pathogenesis and host defense factors for these fungi and their severity, chronicity, and subsequent impact on treatment and prevention of diseases in human or animal hosts.

Case of Fonsecaea nubica chromoblastomycosis from the French territory of Mayotte

INTRODUCTION

Fonsecaea nubica is a newly described species in the genus Fonsecaea.

CASE PRESENTATION

We describe here a clinical case of chromoblastomycosis in a 66-year-old man who presented a 3-year history of leg lesions. F. nubica was identified by morphological and molecular methods. Four months of treatment with itraconazole (300 mg daily) significantly improved the lesions.

CONCLUSION

To the best of our knowledge, this case represents the first clinical case of F. nubica described in France. Particular attention should be paid to microscopic examination for fungal cultures in order to avoid confusion with a contaminating fungus. Moreover, recurrent, wide and deep biopsies should be performed to monitor the evolution of the lesions.

Photodynamic therapy combined with terbinafine against chromoblastomycosis and the effect of PDT on Fonsecaea monophora in vitro

Chromoblastomycosis, a chronic fungal infection of skin and subcutaneous tissue caused by dematiaceous fungi, is associated with low cure and high relapse rates. Among all factors affecting clinical outcome, etiological agents have an important position. In southern China, Fonsecaea pedrosoi and Fonsecaea monophora are main causative agents causing Chromoblastomycosis. We treated one case of chromoblastomycosis by photodynamic therapy (PDT) of 5-aminolevulinic acid (ALA) irradiation combined with terbinafine 250 mg a day. The lesions were improved after two sessions of ALA-PDT treatment, each including nine times, at an interval of 1 week, combined with terbinafine 250 mg/day oral, and clinical improvement could be observed. In the following study, based on the clinical treatment, the effect of PDT and antifungal drugs on this isolate was detected in vitro. It showed sensitivity to terbinafine, itraconazole or voriconazole, and PDT inhibited the growth. Both the clinic and experiments in vitro confirm the good outcome of ALA-PDT applied in the inhibition of F. monophora. It demonstrated that combination of antifungal drugs with ALA-PDT arises as a promising alternative method for the treatment of these refractory cases of chromoblastomycosis.

Therapy of infections caused by dematiaceous fungi

Dematiaceous fungi are responsible for a wide variety of clinical syndromes, from local infections due to trauma, to disseminated infection in immunocompromised patients. These fungi are unique owing to the presence of melanin in their cell walls, which imparts the characteristic dark color to their spores and hyphae. Melanin may also be a virulence factor in these fungi. Therapy depends upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Azoles such as itraconazole and voriconazole have the most consistent in vitro activity, although newer agents may also play a role in therapy in the future.

Epidemiology, Clinical Manifestations, and Therapy of Infections Caused by Dematiaceous Fungi

The dematiaceous (brown-pigmented) fungi are a large and heterogenous group of moulds that cause a wide range of diseases including phaeohyphomycosis, chromoblastomycosis, and eumycotic mycetoma. Among the more important human pathogens are Alternaria species, Bipolaris species, Cladophialophora bantiana, Curvularia species, Exophiala species, Fonsecaea pedrosoi, Madurella species, Phialophora species, Scedosporium prolificans, Scytalidium dimidiatum, and Wangiella dermatitidis. These organisms are widespread in the environment, being found in soil, wood, and decomposing plant debris. Cutaneous, subcutaneous, and corneal infections with dematiaceous fungi occur worldwide, but are more common in tropical and subtropical climates. Infection results from traumatic implantation. Most cases occur in immunocompetent individuals. Dematiaceous moulds are also important causes of invasive sinusitis and allergic fungal sinusitis. Infection is thought to follow inhalation. Although cerebral infection is the commonest form of systemic phaeohyphomycosis, other localized deep forms of the disease, such as arthritis, and endocarditis, have been reported. Disseminated infection is uncommon, but its incidence is increasing, particularly among immunocompromised individuals. Scedosporium prolificans is the most frequent cause. A number of dematiaceous fungi are neurotropic, including Cladophialophora bantiana, Ramichloridium mackenziei, and Wangiella dermatitidis. Although cases have occurred in immunocompromised persons, cerebral phaeohyphomycosis is most common in immunocompetent individuals with no obvious risk factors. Most forms of disease caused by dematiaceous fungi require both surgical and medical treatment. Itraconazole is currently the most effective antifungal agent for chromoblastomycosis and subcutaneous phaeohyphomycosis, while ketoconazole remains useful for mycetoma. Extensive surgical debridement combined with amphotericin B treatment is recommended for chronic invasive sinusitis. Long-term treatment with itraconazole has led to improvement or remission in some patients that had failed to respond to amphotericin B. Allergic fungal sinusitis requires surgical removal of impacted mucin combined with postoperative oral corticosteroids. Antifungal treatment is not usually of benefit, but post-operative itraconazole may reduce the need for reoperation. The clinical outcome of cerebral and other deep-seated forms of phaeohyphomycosis is dismal, with long-term survival being reported only when complete surgical resection of discrete lesions is possible. The development of new antifungal agents and combination treatment may help to improve the management of these infections.

Chromoblastomycosis - A clinical mimic of squamous carcinoma

Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissue caused by dematiaceous fungi. We report a case of chromoblastomycosis caused by Fonsecaea pedrosoi from a subtropical region of India that developed over the left foot of a 45-year-old male farmer and was provisionally diagnosed as squamous cell carcinoma. The patient presented with irregular warty growths over the left foot, which had started one year previously, and has gradually progressed over a year to involve the lateral aspect of left leg. The diagnosis of chromoblastomycosis was confirmed by histopathology and fungal culture.

Challenges in the therapy of chromoblastomycosis

Chromoblastomycosis (CBM) is an implantation mycosis mainly occurring in tropical and subtropical zones worldwide. If not diagnosed at early stages, patients with CBM require long-term therapy with systemic antifungals flanked by various physical treatment regimens. As in other neglected endemic mycoses, comparative clinical trials have not been performed for this disease; nowadays, therapy is mainly based on a few open trials and on expert opinions. Itraconazole, either as monotherapy or associated with other drugs, or with physical methods, is widely used. Recently, photodynamic therapy has been employed successfully in combination with antifungals in patients presenting with CBM. In the present paper, the most used therapeutic options against CBM are reviewed as well as the several factors that may have impact on the patient's outcome.

Subcutaneous fungal infections

Subcutaneous mycoses are common in tropical and subtropical regions of the world. These infections have multiple features in common, including similar epidemiology, mode of transmission, indolent chronic presentation with low potential for dissemination in immunocompetent hosts, and pyogranulomatous lesions on histopathology. Herein, we provide up-to-date epidemiologic, clinical, diagnostic, and therapeutic data for three important subcutaneous mycoses: chromoblastomycosis, mycetoma, and sporotrichosis.

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.

Melanized fungi in human disease

Melanized or dematiaceous fungi are associated with a wide variety of infectious syndromes, including chromoblastomycosis, mycetoma, and phaeohyphomycosis. [corrected]. Many are soil organisms and are generally distributed worldwide, though certain species appear to have restricted geographic ranges. Though they are uncommon causes of disease, melanized fungi have been increasingly recognized as important pathogens, with most reports occurring in the past 20 years. The spectrum of diseases with which they are associated has also broadened and includes allergic disease, superficial and deep local infections, pneumonia, brain abscess, and disseminated infection. For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common etiologic fungi. Melanin is a likely virulence factor for these fungi. Diagnosis relies on careful microscopic and pathological examination, as well as clinical assessment of the patient, as these fungi are often considered contaminants. Therapy varies depending upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Triazoles such as voriconazole, posaconazole, and itraconazole have the most consistent in vitro activity. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.

Extensive long-standing chromomycosis due to Fonsecaea pedrosoi: three cases with relevant improvement under voriconazole therapy

OBJECTIVE

To evaluate voriconazole in the treatment of extensive cases of chromomycosis. Chromomycosis is a chronic infection, which is extremely difficult to eradicate, and is caused by dematiaceous (dark-colored) fungi which affect the skin and subcutaneous tissues, with Fonsecaea pedrosoi being the major etiologic agent. Drugs such as itraconazole, terbinafine, posaconazole and amphotericin B have been employed with variable results.

METHODS

We treated three Caucasian male patients (ages 44, 57 and 77 years), two were farmers and one a trash collector, with long-standing (20, 10 and 21 years of disease, respectively) and extensive chromomycosis (one lower limb affected, at least) due to Fonsecaea pedrosoi. All patients had received previous therapy with the formerly indicated drugs itraconazole and terbinafine for several months either without or with incomplete response. After that, we started treatment with voriconazole per os 200 mg twice a day.

RESULTS

The patients were treated with voriconazole for 12 months until there was clinical and mycological improvement. Clinical response was evident after 30-50 days. One patient developed visual abnormalities and tremors, and the voriconazole was reduced to 200 mg/day without impairment of the clinical and mycological response. The same patient presented photosensitive dermatitis after 12 months of therapy and the voriconazole was stopped. All patients showed elevations of serum gamma-glutamyl transpeptidase (GGT) during the treatment without clinical relevance. Moreover, our three patients obtained partial response with this therapy.

CONCLUSIONS

This is the first report with a case series of chromomycosis treated with voriconazole. Despite its high cost, voriconazole is a safe and possibly promising drug for use on extensive chromomycosis refractory to conventional treatment.

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.

Managing chromoblastomycosis

Chromoblastomycosis is a subcutaneous fungal infection caused by the traumatic inoculation of the skin with pigmented saprophytic moulds. Although infection is rarely fatal, it is characteristically chronic and can be complicated by lymphatic damage and malignant transformation. Despite a variety of treatment modalities, which are often combined and include long courses of antifungals, surgical excision and destructive physical therapies, it remains one of the most difficult deep mycotic infections to eradicate.

Treatment of chromoblastomycosis with terbinafine: Experience with four cases

BACKGROUND

Chromoblastomycosis is a chronic subcutaneous mycosis that occurs more frequently in tropical and subtropical areas and is caused by a group of dematiaceous fungi. It is a difficult-to-treat mycosis with low cure rates and a high rate of relapses.

OBJECTIVE

The objective of this trial is to prove the efficacy and tolerance of oral terbinafine in four cases of chromoblastomycosis.

METHODS AND RESULTS

We included four cases of chromoblastomycosis, proved clinically and mycologically, that are presented herein; three of them caused by Fonsecaea pedrosoi and one by Phialophora verrucosa. Two had a small extension and the other two were of medium and large extension. Oral terbinafine was administered at a dose of 500 mg/day, which was reduced to half in two of the cases once an 80% improvement had been reached; in the third case the initial dose was maintained, and in the fourth case the dose was increased to 750 mg/day. Three cases reached clinical and mycological cure in a mean treatment period of 7 months, the fourth case reached a significant improvement only after 1.2 years of treatment. The medication was well tolerated; no liver alterations occurred; only one patient suffered mild dyspepsia.

CONCLUSION

Terbinafine at 500 mg/day doses represents one of the best treatments for chromoblastomycosis due to its efficacy and excellent tolerability.

Cladophialophora carrionii: a rare agent of chromoblastomycosis in Rio de Janeiro State, Brazil

A 73 year-old male farm laborer from a rural area presented a 15 year history of extensive tumoral lesions over his left leg. Histological studies of skin biopsy showed pseudoepitheliomatous hyperplasia and granulomatous chronic inflammatory process with muriform cells, confirming chromoblastomycosis (CBM). Cladophialophora carrionii was isolated in culture. Treatment with itraconazole 400 mg/day for 12 months resulted in complete remission of lesions. As far we aware, this is the first case report of CBM caused by Cladophialophora carrionii in Rio de Janeiro State, Brazil.

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.

Successful treatment for chromoblastomycosis caused by Fonsecaea monophora: a report of three cases in Guangdong, China

Fonsecaea pedrosoi is the most prevalent aetiological agent of chromoblastomycosis. Fonsecaea monophora is a new species segregated from Fonsecaea pedrosoi. Herein, we report on three cases of chromoblastomycosis caused by F. monophora that were successfully treated with terbinafine and/or itraconazole. Clinical characteristics and mycological parameters are described. Two of the three patients underwent combination therapy with itraconazole and terbinafine during early stages of treatment and were completely healed in a relatively short course of treatment.

Use of terbinafine in rare and refractory mycoses

Terbinafine is the only systemic allylamine antifungal currently available. Its mechanism of action is unique and sets it apart from other agents. Although it is primarily used for dermatophyte infections, such as onychomycosis and tinea pedis, terbinafine has broad in vitro activity against a variety of non-dermatophyte fungal pathogens, including Candida spp. and many molds. In addition, synergistic activity is noted with other antifungals, notably triazoles. Multiple case reports exist of its use for unusual and refractory fungal infections, but no systematic review is available. We review the current literature with regard to in vitro data and clinical experience with terbinafine in the treatment of rare and refractory mycoses.

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.

Dematiaceous fungi

Dematiaceous fungi are responsible for a wide variety of infectious syndromes. They are often found in soil and generally distributed worldwide. This suggests that most if not all individuals are exposed to them, presumably from inhalation or trauma. In recent years, these fungi have been increasingly recognised as important pathogens. The spectrum of diseases they are associated with has also broadened and includes superficial and deep local infections, allergic disease, pneumonia, brain abscess and disseminated infection. For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common aetiological agents. These fungi may have unique pathogenic mechanisms owing to the presence of melanin in their cell walls, which imparts the characteristic dark colour to their spores and hyphae. Diagnosis rests on careful microscopical and pathological examination, as there are no simple laboratory tests to reliably identify these fungi. Therapy depends upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Azoles such as itraconazole and voriconazole have the most consistent in vitro activity, though there is more clinical experience with itraconazole. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.

Severe osteomyelitis caused by Myceliophthora thermophila after a pitchfork injury

BACKGROUND

Traumatic injuries occurring in agricultural settings are often associated with infections caused by unusual organisms. Such agents may be difficult to isolate, identify, and treat effectively.

CASE REPORT

A 4-year-old boy developed an extensive infection of his knee and distal femur following a barnyard pitchfork injury. Ultimately the primary infecting agent was determined to be Myceliophthora thermophila, a thermophilic melanized hyphomycete, rarely associated with human infection, found in animal excreta. Because of resistance to standard antifungal agents including amphotericin B and caspofungin, therapy was instituted with a prolonged course of terbinafine and voriconazole. Voriconazole blood levels demonstrated that the patient required a drug dosage (13.4 mg/kg) several fold greater than that recommended for adults in order to attain therapeutic blood levels.

CONCLUSION

Unusual pathogens should be sought following traumatic farm injuries. Pharmacokinetic studies may be of critical importance when utilizing antifungal therapy with agents for which little information exists regarding drug metabolism in children.