Molecular characterization of pathogenic members of the genus Fonsecaea using multilocus analysis

Antifungal Susceptibility of Melanized Fungi Isolated from CARD9 Deficient Patients: Implications for Treatment of Refractory Infections

BACKGROUND

Inherited genetic deficiencies in the Caspase-associated recruitment domain-containing protein 9 (CARD9) lead to increased susceptibility of patients to opportunistic melanized fungi. Such infections are recalcitrant, and the fungus possibly acquires resistance under therapy.

OBJECTIVE

To evaluate differences of in vitro antifungal susceptibility of strains of melanized fungi originating from patients with CARD9 deficiency versus strains from chronic patients with unclear genetic background.

METHODS

We analyzed a total of 118 isolates, including 33 from patients with CARD9 deficiency, 80 from chronic patients with other undefined immunological features, and 5 environmental strains, all collected between 1997 and 2021. All isolates were identified by sequencing the ITS spacer of the rDNA operon. Broth microdilution susceptibility tests were performed according to CLSI guidelines (M38-A3document).

RESULTS

MIC ranges of strains from infected patients having CARD9 deficiency and other individuals were mostly similar. However, comparing these two groups, the GM MICs of posaconazole, amphotericin B and fluconazole in the CARD9 group were statistically higher and the GM MICs of terbinafine lower than those of undefined genetic background group. The FICI of the CARD9 group were higher than those of the undefined group in the combination of caspofungin plus amphotericin B and amphotericin B plus fluconazole, but lower than the undefined group in the combination of itraconazole plus terbinafine.

CONCLUSIONS

The GM MICs for posaconazole, amphotericin B, and fluconazole were significantly elevated in the CARD9 group compared to the group with undefined chronic infections. For patients with refractory infections, conducting susceptibility testing before treatment can optimize the selection of the most effective therapeutic agent, and the combination therapy of caspofungin with amphotericin B or itraconazole may be considered the preferred treatment option.

Rapid classification of chromoblastomycosis agents genera by infrared spectroscopy and chemometrics supervised by sequencing of rDNA regions

Chromoblastomycosis (CBM) is a skin and subcutaneous infection caused by species of seven fungal genera. Identification of CBM species is performed by DNA sequencing of one or more genes, which becomes a time-consuming work. Fourier Transform Infrared Spectroscopy (FTIR) has been used for the identification of other microorganisms, however, only one CBM genus was evaluated by FTIR analysis to date. Therefore, the study is aimed to differentiate the CBM agents for identification at genera level using FTIR supervised by Internal Transcribed Spacer (ITS) rDNA region. Seventy-seven isolates of the main five CBM genera were prepared for Attenuated Total Reflection FTIR (ATR-FTIR) with a new methodology using slices of dry fungus in glass fixing-modeling proposed in this study. The algorithm Hierarchical Cluster Analysis (HCA) was used to analyze the differences and similarities between species through the spectra. Orthogonal Partial Least Square Discriminant Analysis (OPLS-DA) allowed to correctly classify all samples of five CBM genera. The ATR-FTIR/OPLS-DA models highlighted important contributions of regions attributed to NH and OH stretching, amide I of proteins, polysaccharides bands and fingerprint region for the complete differentiation of the genera investigated. Thus, FTIR can be a fast and inexpensive alternative for identification of CBM agents.

[Chromoblastomycosis]

The paper describes a case of chromoblastomycosis, a rare implantation mycosis in the Russian Federation. It gives data on the prevalence, etiology, and clinical presentations of the disease, and the diagnostic possibilities. Emphasis is laid on the leading role of a pathomorphological study in the diagnosis of chromoblastomycosis in non-endemic countries, including Russia. The clinical and pathomorphological presentations are described in detail. Histological examination detected 5-12-µm spherical or polygonal pigmented cells that are fungal elements, which allows chromoblastomycosis to be diagnosed in the cytoplasm of macrophages and extracellularly. A refusal to conduct a pathomorphological study leads to diagnostic errors and an irrational treatment policy.

Chromoblastomycosis in an Endemic Area of Brazil: A Clinical-Epidemiological Analysis and a Worldwide Haplotype Network

Chromoblastomycosis (CBM) is a neglected implantation mycosis prevalent in tropical climate zones, considered an occupational disease that affects impoverished rural populations. This retrospective study described clinical aspects of CBM in a hyperendemic area in Brazil and constructed a worldwide haplotype network of Fonsecaea spp. strains. The variables were collected from medical records using a standard report form, reporting 191 patients with CBM from Maranhão, Brazil. The mean age was 56.1 years, 168 (88%) patients were male and predominantly farmers (85.8%). The mean time of evolution of the disease until diagnosis was 9.4 years. Lower limbs (81.2%) and upper limbs (14.2%) were the main sites affected. Most patients exhibited verrucous (55%) and infiltrative plaque (48.2%). Fonsecaea spp. were identified in 136 cases and a haplotype network constructed with ITS sequences of 185 global strains revealed a total of 59 haplotypes exhibiting high haplotypic and low nucleotide diversities. No correlation was observed between the different haplotypes of Fonsecaea species and dermatological patterns, severity of disease or geographic distribution inside Maranhão. Data from this area contributed to better understanding the epidemiology of CBM. For the first time, a robust haplotype network with Fonsecaea strains reveals an evolutionary history with a recent population expansion.

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.

New Molecular Markers Distinguishing Fonsecaea Agents of Chromoblastomycosis

The species belonging to the genus Fonsecaea are the main causative agents of chromoblastomycosis. The invasive potential of Fonsecaea differs significantly among its various sibling species. Moreover, the lack of clarity on the virulence and availability of precise markers to distinguish and detect Fonsecaea species is attributed to the different ways of dissemination and pathogenicity. Therefore, the present study aimed to propose new molecular tools to differentiate between sibling species causing chromoblastomycosis. We used an infection model of chromoblastomycosis in BALB/c to study species-specific molecular markers for the in vivo detection of Fonsecaea species in biological samples. Specific primers based on the CBF5 gene were developed for Fonsecaea pedrosoi, Fonsecaea monophora, Fonsecaea nubica, and Fonsecaea pugnacius. In addition, a padlock probe was designed for F. pugnacius based on ITS sequences. We also assessed the specificity of Fonsecaea species using in silico, in vitro, and in vivo assays. The results showed that markers and probes could effectively discriminate the species in both clinical and environmental samples, enabling bioprospecting of agents of chromoblastomycosis, thereby elucidating the infection route of the disease.

Chromoblastomycosis Caused by Fonsecaea nubica: First Report in Northern China and Literature Review

Chromoblastomycosis is found worldwide with higher incidence in tropical and subtropical regions. Fonsecaea spp. is one of the major causative agents of this disease. First case of chromoblastomycosis due to Fonsecaea nubica in Northern China is reported in a 75-year-old Chinese male. We firstly summarized molecular identification methods of Fonsecaea spp. and all the strains of F. nubica reported in the literature. Sequencing of internal transcribed spacer alone and/or combined with actin (ACT1), partial cell division cycle (CDC42) and partial beta-tubulin (BT2) were most commonly used to identify species, while lactase (Lac), homogentisate (HmgA) and polyketide synthase (PKS1) were also used in some cases. Most strains were isolated from South America and Eastern China. Five clinical cases of chromoblastomycosis due to F. nubica from Asia and Europe were also reviewed. All the five patients were male, over 30 years old, and their lesions occurred after trauma.

Molecular identification of chromoblastomycosis clinical isolates in Guangdong

Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissue. The most common etiologic agent encountered in Southern China is from the genus Fonsecaea. Fonsecaea species are often misidentified due to indistinct morphology features; furthermore, recent taxonomy revision was done on the fungi genus. Herein, a comprehensive evaluation with molecular sequencing data based on internal transcribed spacer (ITS) ribosomal DNA regions as molecular targets were implemented to 37 clinical isolates from chromoblastomycosis patients. Twenty strains that were formerly identified as Fonsecaea pedrosoi through morphological characteristic were verified to be either Fonsecaea nubica or Fonsecaea monophora, while 17 strains were appropriately identified as F. monophora. A phylogenetic method was further performed to establish the species delimitation. Our investigations validate that the clinical isolates from Guangdong consist of F. monophora and the recently found new species, F. nubica. In this study, F. pedrosoi has not been isolated from chromoblastomycosis patients in Guangdong, Southern China. Reevaluation of previous reports regarding F. pedrosoi as chromoblastomycosis etiologic agent in China is necessary for a comprehensive assessment of geographic distribution pattern of Fonsecaea species. This study is the first reported study presenting large samples of F. nubica domestic or abroad.

Indoor wet cells as a habitat for melanized fungi, opportunistic pathogens on humans and other vertebrates

Indoor wet cells serve as an environmental reservoir for a wide diversity of melanized fungi. A total of 313 melanized fungi were isolated at five locations in Guangzhou, China. Internal transcribed spacer (rDNA ITS) sequencing showed a preponderance of 27 species belonging to 10 genera; 64.22% (n = 201) were known as human opportunists in the orders Chaetothyriales and Venturiales, potentially causing cutaneous and sometimes deep infections. Knufia epidermidis was the most frequently encountered species in bathrooms (n = 26), while in kitchens Ochroconis musae (n = 14), Phialophora oxyspora (n = 12) and P. europaea (n = 10) were prevalent. Since the majority of species isolated are common agents of cutaneous infections and are rarely encountered in the natural environment, it is hypothesized that indoor facilities explain the previously enigmatic sources of infection by these organisms.

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

Chromoblastomycosis is a mutilating infection of the skin and subcutaneous tissues caused by melanized fungi belonging to the order Chaetothyriales. Proven cases of the main agent, Fonsecaea pedrosoi are mainly limited to (sub)tropical, humid climates of Latin and Central America and the Caribbean. Fonsecaea monophora has a global distribution along the equator. Cases outside the (sub)tropics have thus far mostly been considered to have been imported, but here we report the first endemic case by F. monophora from Argentina. Patient was a 82-year-old rural female worker from Corrientes, a province with a dry continental climate.

Successful treatment of chromoblastomycosis of 10-year duration due to Fonsecaea nubica

We report a case of chromoblastomycosis due to the presence of large plaque and verrucous hyperplasia lesions on the left upper limb, with elbow abnormal activities, in a 56-year-old male. The diagnosis of chromoblastomycosis was based on gross and microscopic morphologies, histopathological examination and clinical manifestation. Molecular tools were applied to identifying the causative agent Fonsecaea nubica, which is rarely reported to be associated with chromoblastomycosis. The patient was initially treated orally with terbinafine (250 mg/day) and itraconazole (200 mg/day), subsequently patient received thermotherapy (45-50°C, 3 h/day) for 1 month. The patient was successfully cured. A literature review was performed to assess general features, treatment and outcome of chromoblastomycosis due to F.  nubica. All the 5 reviewed patients were male, over 30 years old and their lesions occurred after traumatic inoculation.

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.

Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota)

The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sex-related genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi.

Molecular Epidemiology of Agents of Human Chromoblastomycosis in Brazil with the Description of Two Novel Species

The human mutilating disease chromoblastomycosis is caused by melanized members of the order Chaetothyriales. To assess population diversity among 123 clinical strains of agents of the disease in Brazil we applied sequencing of the rDNA internal transcribed spacer region, and partial cell division cycle and β-tubulin genes. Strains studied were limited to three clusters divided over the single family Herpotrichiellaceae known to comprise agents of the disease. A Fonsecaea cluster contained the most important agents, among which F. pedrosoi was prevalent with 80% of the total set of strains, followed by 13% for F. monophora, 3% for F. nubica, and a single isolate of F. pugnacius. Additional agents, among which two novel species, were located among members of the genus Rhinocladiella and Cyphellophora, with frequencies of 3% and 1%, respectively.

Chromoblastomycosis, a skin disease found among rural populations in tropical and subtropical regions, is caused by melanized fungi related to the black yeasts. The present study evaluates the species distribution among 123 clinical strains from endemic areas in Brazil based on multilocus sequence data, and describes two new agents of the disease which proved to be affiliated to Rhinocladiella and Cyphellophora.

Cerebral phaeohyphomycosis by Fonsecaea monophora: Report in a patient with AIDS and a ring enhancing lesion

Fungal infections are infrequent causes of brain abscesses. Fonsecaea monophora is a dematiaceous fungus that appears to be neurotropic. We report a case of Fonsecaea monophora infection in a patient with acquired immunodeficiency syndrome, and review previous reports of brain abscesses by this organism.

Shared Physiological Traits of Exophiala Species in Cold-Blooded Vertebrates, as Opportunistic Black Yeasts

Several species of the genus Exophiala are found as opportunistic pathogens on humans, while others cause infections in cold-blooded waterborne vertebrates. Opportunism of these fungi thus is likely to be multifactorial. Ecological traits [thermotolerance and pH tolerance, laccase activity, assimilation of mineral oil, and decolorization of Remazol Brilliant Blue R (RBBR)] were studied in a set of 40 strains of mesophilic Exophiala species focused on the salmonis-clade mainly containing waterborne species. Thermophilic species and waterborne species outside the salmonis-clade were included for comparison. Strains were able to tolerate a wide range of pHs, although optimal growth was observed between pH 4.0 and 5.5. All strains tested were laccase positive. Strains were able to grow in the presence of the compounds (mineral oil and RBBR) with some differences in assimilation patterns between strains tested and also were capable of degrading the main chromophore of RBBR. The study revealed that distantly related mesophilic species behave similarly, and no particular trend in evolutionary adaptation was observed.

The role of melanin pathways in extremotolerance and virulence of Fonsecaea revealed by de novo assembly transcriptomics using illumina paired-end sequencing

Melanisation has been considered to be an important virulence factor of Fonsecaea monophora. However, the biosynthetic mechanisms of melanisation remain unknown. We therefore used next generation sequencing technology to investigate the transcriptome and digital gene expression data, which are valuable resources to better understand the molecular and biological mechanisms regulating melanisation in F. monophora. We performed de novo transcriptome assembly and digital gene expression (DGE) profiling analyses of parent (CBS 122845) and albino (CBS 125194) strains using the Illumina RNA-seq system. A total of 17 352 annotated unigenes were found by BLAST search of NR, Swiss-Prot, Gene Ontology, Clusters of Orthologous Groups and Kyoto Encyclopedia of Genes and Genomes (KEGG) (E-value <1e‒5). A total of 2 283 unigenes were judged to be the differentially expressed between the two genotypes. We identified most of the genes coding for key enzymes involved in melanin biosynthesis pathways, including polyketide synthase (pks), multicopper oxidase (mco), laccase, tyrosinase and homogentisate 1,2-dioxygenase (hmgA). DEG analysis showed extensive down-regulation of key genes in the DHN pathway, while up-regulation was noted in the DOPA pathway of the albino mutant. The transcript levels of partial genes were confirmed by real time RT-PCR, while the crucial role of key enzymes was confirmed by either inhibitor or substrate tests in vitro. Meanwhile, numbers of genes involved in light sensing, cell wall synthesis, morphology and environmental stress were identified in the transcriptome of F. monophora. In addition, 3 353 SSRs (Simple Sequence Repeats) markers were identified from 21 600 consensus sequences. Blocking of the DNH pathway is the most likely reason of melanin deficiency in the albino strain, while the production of pheomelanin and pyomelanin were probably regulated by unknown transcription factors on upstream of both pathways. Most of genes involved in environmental tolerance to oxidants, irradiation and extreme temperatures were also assembled and annotated in transcriptomes of F. monophora. In addition, thousands of identified cSSR (combined SSR) markers will favour further genetic linkage studies. In conclusion, these data will contribute to understanding the regulation of melanin biosynthesis and help to improve the studies of pathogenicity of F. monophora.

Global Spread of Human Chromoblastomycosis Is Driven by Recombinant Cladophialophora carrionii and Predominantly Clonal Fonsecaea Species

Global distribution patterns of Cladophialophora carrionii, agent of human chromoblastomycosis in arid climates of Africa, Asia, Australia, Central-and South-America, were compared with similar data of the vicarious Fonsecaea spp., agents of the disease in tropical rain forests. Population diversities among 73 C. carrionii strains and 60 strains of three Fonsecaea species were analyzed for rDNA ITS, partial β-tubulin, and amplified fragment-length polymorphism (AFLP) fingerprints. Populations differed significantly between continents. Lowest haplotype diversity was found in South American populations, while African strains were the most diverse. Gene flow was noted between the African population and all other continents. The general pattern of Fonsecaea agents of chromoblastomycosis differed significantly from that of C. carrionii and revealed deeper divergence among three differentiated species with smaller numbers of haplotypes, indicating a longer evolutionary history.

First case of chromoblastomycosis from Bangladesh

Chromoblastomycosis is a rare and chronic cutaneous and subcutaneous infection caused by black fungi and mostly reported in tropical and subtropical areas. Here we report the first case of chromoblastomycosis from Bangladesh. Molecular biology permitted to identify Fonsecaea nubica, and the patient responded well to antifungal treatment alone.

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Difficulty of clinical diagnosis of chromoblastomycosis in European countries.

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Histology and mycological cultures for skin lesions in patients presenting a small erythematous nodule or plaque after an injury in a tropical country.

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Molecular biology needed for identification of the species involved in chromoblastomycosis.

Fonsecaea pugnacius, a Novel Agent of Disseminated Chromoblastomycosis

We report a fatal case of a chromoblastomycosis-like infection caused by a novel species of Fonsecaea in a 52-year-old immunocompetent Caucasian male from an area of chromoblastomycosis endemicity in Brazil. The patient had a 30-year history of slowly evolving, verrucous lesions on the right upper arm which gradually affected the entire arm, the left hemifacial area, and the nose. Subsequent dissemination to the brain was observed, which led to death of the patient. The internal transcribed spacer (ITS) and partial large subunit (LSU), BT2, and CDC42 genes of the isolates recovered from skin and brain were sequenced, confirming the novelty of the species. The species is clinically unique in causing brain abscesses secondary to chromoblastomycosis lesions despite the apparent intact immunity of the patient. Histopathologic appearances were very different, showing muriform cells in skin and hyphae in brain.

Chromoblastomycosis due to Fonsecaea monophora in a man with nephritic syndrome

Chromoblastomycosis is a chronic subcutaneous mycosis caused by dematiaceous fungi. Fonsecaea monophora, a new species segregated from F. pedrosoi, may be the most prevalent pathogen of chromoblastomycosis in southern China. Herein, we report a rare case of chromoblastomycosis in a man with nephritic syndrome. He presented with an asymptomatic red plaque on the back of his left wrist that had appeared and enlarged over a period of 1.5 years, without any prior trauma. He was initially diagnosed with sporotrichosis. However, he did not respond to a 6-month course of potassium iodide treatment. The lesion slowly enlarged and became verrucous instead. Concurrently, a similar maculopapule appeared on his left forearm. Histopathological examination of a biopsy specimen indicated the presence of sclerotic bodies in the dermis. The fungus was identified as Fonsecaea spp. based on the results of a slide culture; in addition, the agent was confirmed to be F. monophora by using molecular methods. The patient demonstrated marked improvement after receiving appropriate antifungal therapy for 3 months. To our knowledge, this is the first case of chromoblastomycosis caused by F. monophora in an immunosuppressed patient. The identification of the agent by molecular techniques is important for epidemiological purposes. Thus, we believe that combination therapy with itraconazole and terbinafine would be a suitable option for infections caused by F. monophora.

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.