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

Misleading subcutaneous mycosis: a case report of subsequent clinical mycetoma-like and histological chromoblastomycosis-like lesions

Hyalohyphomycosis and phaeohyphomycosis are groups of mycoses caused by several agents and show different clinical manifestations. We report a case of an immunocompromised patient who presented rare manifestations of opportunistic mycoses: mycetoma-like hyalohyphomycosis on his right foot caused by Colletotrichum gloeosporioides, followed by cutaneous phaeohyphomycosis on his right forearm caused by Exophiala oligosperma. Further to the rarity of this case, the patient's lesion on the foot shows that the clinical aspects of mycetomas could falsely appear in other fungal infections similar to hyalohyphomycosis. We also show that the muriform cells that were seen in the direct and anatomopathological examination of the skin are not pathognomonic of chromoblastomycosis, as observed in the lesion of the patient's forearm.

An unusual presentation of extragenital lichen sclerosus-An extensive keratotic variant

In this case report, we outline a case of a 71-year-old woman who presented to the dermatology clinic with a history of keratotic and atrophic warty-like plaques on her lower limbs, which limited the movements in her right lower extremity. A skin radial biopsy of one of the plaques was performed and the diagnosis of extragenital lichen sclerosus (ELS) was established. She underwent an anogenital exam and fortunately, lesions were not found. The patient in this case showed an unusual variant of ELS.

Resazurin to determine the minimum inhibitory concentration on antifungal susceptibility assays for Fonsecaea sp. using a modified EUCAST protocol

Chromoblastomycosis is a fungal chronic disease, which affects humans, especially in cutaneous and subcutaneous tissues. There is no standard treatment for Chromoblastomycosis, and it is a therapeutic challenge, due natural resistance of their causative agents, inadequate response of patients and common cases of relapse. Protocols for determination of antifungal drugs susceptibility are not standardized for chromoblastomycosis agents and endpoint definition is usually based on visual inspection, which depends on the analyst, making it sometimes inaccurate. We presented a colorimetric and quantitative methodology based on resazurin reduction to resofurin to determine the metabolic status of viable cells of Fonsecaea sp. Performing antifungal susceptibility assay by a modified EUCAST protocol allied to resazurin, we validated the method to identify the minimum inhibitory concentrations of itraconazole, fluconazole, amphotericin B, and terbinafine for eight Fonsecaea clinical isolates. According to our data, resazurin is a good indicator of metabolic status of viable cells, including those exposed to antifungal drugs. This work aimed to test resazurin as an indicator of the metabolic activity of Fonsecaea species in susceptibility assays to antifungal drugs. Species of this genus are the main causative agents of Chromoblastomycosis, which affects humans.

Prediction of melanin content of Fonsecaea pedrosoi using Fourier transform infrared spectroscopy (FTIR) and chemometrics

Fungal melanin contributes to the survival and virulence of pathogenic fungi, such as Fonsecaea pedrosoi, which is responsible for causing chromoblastomycosis. The objective of this study was to employ Fourier transform infrared spectroscopy (FTIR) to predict the melanin content of F. pedrosoi. The melanin content, in percentage, was previously determined using gravimetry for twenty-six clinical isolates. Quintuplicate spectra of each isolate were obtained using attenuated total reflection (ATR) within the range of 4000 to 650 cm-1. To predict the melanin content, modeling was performed using partial least squares regression (PLS) in the region 1800 - 750 cm-1. Two models were tested: PLS and successive projections algorithms for interval selection in partial least squares (iSPA-PLS). The best modeling results were achieved using iSPA-PLS with one factor. The calibration set exhibited a determination coefficient (R2) of 0.9745 and a root mean square error of cross-validation (RMSECV) of 0.0977. In the prediction set, the R2 value was 0.9711, and the root mean square error of prediction (RMSEP) was 0.0999. Modeling with FTIR and multivariate calibration provides a valuable means of predicting fungal melanin content, which is simpler and more robust, thereby contributing to the advancement of this field of study.

Comparison of the antifungal activity of the pyrimidine analogs flucytosine and carmofur against human-pathogenic dematiaceous fungi

Chromoblastomycosis (CBM) and pheohyphomycosis (PHM) are the most common implantation mycoses caused by dematiaceous fungi. In the past, flucytosine (5-FC) has been used to treat CBM, but development of resistance is common. Carmofur belongs to the same class as 5-FC and has in vitro inhibitory activity against the main agents of CBM and PHM. The aim of this study was to compare the action of these two pyrimidine analog drugs against CBM and PHM agents. The minimum inhibitory concentration (MIC) and the selectivity index based on cytotoxicity tests of these two drugs against some agents of these mycoses were determined, with carmofur presenting a higher selectivity index than 5-FC. Carmofur demonstrated here synergistic interactions with itraconazole and amphotericin B against Exophiala heteromorpha, Fonsecaea pedrosoi, Fonsecaea monophora, and Fonsecaea nubica strains. Additionally, carmofur plus itraconazole demonstrated here synergism against a Phialophora verrucosa strain. To evaluate the development of carmofur resistance, passages in culture medium containing subinhibitory concentrations of this pyrimidine analog were carried out, followed by in vitro susceptibility tests. Exophiala dermatitidis quickly developed resistance, whereas F. pedrosoi took seven passages in carmofur-supplemented medium to develop resistance. Moreover, resistance was permanent in E. dermatitidis but transient in F. pedrosoi. Hence, carmofur has exhibited certain advantages, albeit accompanied by limitations such as the development of resistance, which was expected as with 5-FC. This underscores its therapeutic potential in combination with other drugs, emphasizing the need for a meticulous evaluation of its application in the fight against dematiaceous fungi.

Identification of Chromoblastomycosis and Phaeohyphomycosis Agents through ITS-RFLP

Chromoblastomycosis (CBM) and phaeohyphomycosis (FEO) are infections caused by melanized filamentous fungal agents, primarily found in tropical and subtropical regions. Both infections pose significant challenges for the correct identification of the causative agent due to their morphological similarity, making conventional methods of morphological analysis highly subjective. Therefore, molecular techniques are necessary for the precise determination of these species. In this regard, this study aimed to contribute to a new methodology based on PCR-RFLP for the identification of agents causing CBM and FEO. Sequences from the Internal Transcribed Spacer (ITS) region were used to identify potential restriction enzyme sites in silico, followed by in vitro validation using the selected restriction enzymes. The obtained results were compared with species identification through morphological analyses and sequencing. The results demonstrated that the PCR-RFLP applied in this study accurately identified two major agents of chromoblastomycosis, Fonsecaea pedrosoi and Fonsecaea monophora, as well as Cladophialophora bantiana and Exophiala dermatitidis, both causative agents of phaeohyphomycosis. In this context, the proposed assay can complement current methods for identifying these species, aiding in diagnosis, and contributing to the proper management of these infections.

Chromoblastomycosis Caused by Fonsecaea monophora Mimicking Lichen Planus

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

From Child to Old Man: A Slowly Evolving Case of Chromoblastomycosis Caused by Cladosporium cladosporioides

Chromoblastomycosis is a chronic granulomatous mycosis of the skin and subcutaneous tissue caused by traumatic inoculation with dematiaceous fungi. This disease primarily affects agricultural workers, who are mostly men. We present a case of chromoblastomycosis in a 63-year-old male farmer patient with dermatosis over 50 years of evolution, with warty, erythematous, and scaly plaques that predominate on the left hemithorax. Direct examination with potassium hydroxide (KOH) revealed numerous fumagoid cells. Amplification and sequencing of the internal transcribed spacer (ITS) and translation elongation factor 1-alpha (TEF-1a) gene revealed that chromoblastomycosis was caused by Cladosporium cladosporioides. The chromoblastomycosis was treated with itraconazole and fluconazole without any improvement, and amphotericin B was administered with partial improvement.

Chromoblastomycosis: New Perspective on Adjuvant Treatment with Acitretin

Chromoblastomycosis (CBM) is a neglected human disease, caused by different species of pigmented dematiaceous fungi that cause granulomatous and suppurative dermatosis. This infection is difficult to treat and there are limited therapeutic options, including terbinafine, itraconazole, and tioconazole. Classic treatment is administered for a long period of time, but some patients do not respond properly, and therefore, such therapeutic approaches possess low cure rates. Therefore, it is vital to develop new strategies for the treatment of CBM. In this regard, it has been observed that the association of immunomodulatory molecules such as glucan with therapy carried out with antifungal drugs improves cutaneous lesions in comparison to treatment with antifungal drugs alone, suggesting that drug association may be an interesting and significant approach to incorporate into CBM therapy. Thus, the aim of this work was to associate classical antifungal therapy with the adjuvants imiquimod and acitretin. In the present case, we reported a patient with extensive CBM caused by Fonsaecae pedrosoi, that affected an extensive area of the right leg, that was left without treatment for 11 years. He was treated with a classical combination of itraconazole and terbinafine via the oral route plus topical imiquimod and oral acitretin, as an adjuvant therapy. After five months of treatment, a significant regression of verrucous plaques was observed, suggesting that the use of these adjuvants combined with the classical antifungal drugs, intraconazole plus terbinafine, can reduce treatment time and rapidly improve the patient's quality of life. This result confirms that the use of coadjuvant drugs may be effective in the treatment of this infectious disease.

Destructive Facial Plaque and Palatal Perforation in a Middle-Aged Woman

A woman in her 30s had asymptomatic erythematous scaly plaques over the face and proximal extremities. The lesions started as a erythematous papule on the face, which had progressed to larger plaques within 10 years. What is your diagnosis?

Role of Dectin-1 in immune response of macrophages induced by Fonsecaea monophora wild strain and melanin-deficient mutant strain

Chromoblastomycosis is a chronic granulomatous subcutaneous fungal disease caused mainly by Fonsecaea monophora in southern China. Melanin is an important virulence factor in wild strain (Mel+), and the strains lack of the polyketide synthase gene is a melanin-deficient mutant strain (Mel-). We investigated the effect of melanin in F. monophora on Dectin-1 receptor-mediated immune responses in macrophages. Conidia and tiny hyphae of Mel+ and Mel- were co-cultured with THP-1 macrophages expressing normal or low levels of Dectin-1. Compare the killing rate, phagocytosis rate, and expression levels of the inflammatory cytokines tumour necrosis factor-α, interleukin-1β, interleukin-6, and nitric oxide in each group. The results showed that the killing rate, phagocytosis rate, and pro-inflammatory factor levels of Mel+ infected macrophages with normal expression of Dectin-1 were lower than those of Mel-. And the knockdown of Dectin-1 inhibited the phagocytic rate, killing rate, and proinflammatory factor expression in macrophages infected with Mel+ and Mel-. And there was no significant difference in the above indexes between Mel+ and Mel- groups in Dectin-1 knockdown macrophages. In summary, the study reveals that melanin of F. monophora inhibits the immune response effect of the host by hindering its binding to Dectin-1 on the surface of macrophage, which may lead to persistent fungal infections.

Role of cytopathology in diagnosing phaeohyphomycosis masquerading as nerve abscess in a lepromatous leprosy patient: A case report

INTRODUCTION AND IMPORTANCE

Phaeohyphomycosis is a rare fungal infection primarily affecting immunocompromised individuals. Its clinical manifestations are diverse, and diagnosis can be challenging, particularly when lesions mimic other conditions.

CASE PRESENTATION

A 66-year-old male, with a history of irregular leprosy treatment and prolonged steroid use, presented with symptoms suggestive of a nerve abscess. On examination, cystic swellings were observed on the left thumb and leg. Histopathological examination and fine needle aspiration cytology (FNAC) revealed melanized hyphae, leading to a final diagnosis of phaeohyphomycosis. The patient was treated with oral itraconazole, leading to regression in lesion size.

CLINICAL DISCUSSION

Leprosy patients on long-term steroids are especially susceptible. The pathogenicity of these fungi in immunocompetent people is believed to be due to melanin in their cell walls, which defends against host defenses. Diagnosis involves histopathological examinations, staining, and fungal culture. Treatment involves surgical excision and antifungal drugs. If untreated, it can lead to severe complications including fatal brain infections.

CONCLUSION

This case highlights the unusual presentation of phaeohyphomycosis mimicking a nerve abscess in a leprosy patient. It underscores the importance of a high degree of clinical suspicion in diagnosing such rare infections, particularly in immunocompromised individuals. It also emphasizes the value of FNAC in reaching a definitive diagnosis. Prompt diagnosis and appropriate treatment are essential to prevent potentially serious outcomes.

Repurposing Benzimidazoles against Causative Agents of Chromoblastomycosis: Albendazole Has Superior In Vitro Activity Than Mebendazole and Thiabendazole

Chromoblastomycosis (CBM) is a neglected human implantation mycosis caused by several dematiaceous fungal species. Currently available therapy is usually associated with physical methods, especially surgery, and with high refractoriness. Therefore, drug discovery for CBM is essential. Drug repositioning is a strategy used to facilitate the discovery of new treatments for several diseases. The aim of this study was to discover substances with antifungal activity against CBM agents from a collection of drugs previously approved for use in human diseases. A screening was performed with the NIH Clinical Collection against Fonsecaea pedrosoi. Ten substances, with clinical applicability in CBM, inhibited fungal growth by at least 60%. The minimum inhibitory concentration (MIC) of these substances was determined against other CBM agents, and the benzimidazoles albendazole, mebendazole and thiabendazole presented the lowest MIC values. The selectivity index, based on MIC and cytotoxicity of these substances, revealed albendazole to be more selective. To investigate a possible synergism of this benzimidazole with itraconazole and terbinafine, the chequerboard method was used. All interactions were classified as indifferent. Our current results suggest that benzimidazoles have repositioning potential against CBM agents. Albendazole seems to be the most promising, since it presented the highest selectivity against all dematiaceous fungi tested.

Nine new species of black lichenicolous fungi from the genus Cladophialophora (Chaetothyriales) from two different climatic zones of China

Lichenicolous fungi are parasites of lichens. Many of these fungi are referred to as "black fungi". A diversity of these black fungi include species that are pathogenic to humans and plants. A majority of black fungi reside in the phylum Ascomycota within the sub-classes Chaetothyriomycetidae and Dothideomycetidae. To explore the diversity of lichenicolous "black fungi" associated with lichens in China, we conducted several field surveys in the Inner Mongolia Autonomous Region and Yunnan Province between 2019 and 2020. We recovered 1,587 fungal isolates from the lichens collected during these surveys. During the preliminary identification of these isolates using the complete internal transcribed spacer (ITS), partial large subunit of nuclear ribosomal RNA gene (LSU), and small subunit of nuclear ribosomal RNA gene (SSU), we identified 15 fungal isolates from the genus Cladophialophora. However, these isolates had low sequence similarities with all known species from the genus. Therefore, we amplified additional gene regions, such as, translation elongation factor (TEF) and partial β-tubulin gene (TUB), and constructed a multi-gene phylogeny using maximum likelihood, maximum parsimony, and Bayesian inference. In our datasets, we included type sequences where available for all Cladophialophora species. Phylogenetic analyses revealed that none of the 15 isolates belonged to any of the previously described species in the genus. Therefore, using both morphological and molecular data, we classified these 15 isolates as nine new species within the genus Cladophialophora: C. flavoparmeliae, C. guttulate, C. heterodermiae, C. holosericea, C. lichenis, C. moniliformis, C. mongoliae, C. olivacea, and C. yunnanensis. The outcome from this study shows that lichens are an important refugia for black lichenicolous fungi, such as those from Chaetothyriales.

Clinical Manifestations of Human Exposure to Fungi

Biological particles, along with inorganic gaseous and particulate pollutants, constitute an ever-present component of the atmosphere and surfaces. Among these particles are fungal species colonizing almost all ecosystems, including the human body. Although inoffensive to most people, fungi can be responsible for several health problems, such as allergic fungal diseases and fungal infections. Worldwide fungal disease incidence is increasing, with new emerging fungal diseases appearing yearly. Reasons for this increase are the expansion of life expectancy, the number of immunocompromised patients (immunosuppressive treatments for transplantation, autoimmune diseases, and immunodeficiency diseases), the number of uncontrolled underlying conditions (e.g., diabetes mellitus), and the misusage of medication (e.g., corticosteroids and broad-spectrum antibiotics). Managing fungal diseases is challenging; only four classes of antifungal drugs are available, resistance to these drugs is increasing, and no vaccines have been approved. The present work reviews the implications of fungal particles in human health from allergic diseases (i.e., allergic bronchopulmonary aspergillosis, severe asthma with fungal sensitization, thunderstorm asthma, allergic fungal rhinosinusitis, and occupational lung diseases) to infections (i.e., superficial, subcutaneous, and systemic infections). Topics such as the etiological agent, risk factors, clinical manifestations, diagnosis, and treatment will be revised to improve the knowledge of this growing health concern.

Silver(I) 1,10-Phenanthroline Complexes Are Active against Fonsecaea pedrosoi Viability and Negatively Modulate Its Potential Virulence Attributes

The genus Fonsecaea is one of the etiological agents of chromoblastomycosis (CBM), a chronic subcutaneous disease that is difficult to treat. This work aimed to evaluate the effects of copper(II), manganese(II) and silver(I) complexes coordinated with 1,10-phenanthroline (phen)/1,10-phenanthroline-5,6-dione (phendione) on Fonsecaea spp. Our results revealed that most of these complexes were able to inhibit F. pedrosoi, F. monophora and F. nubica conidial viability with minimum inhibitory concentration (MIC) values ranging from 0.6 to 100 µM. The most effective complexes against F. pedrosoi planktonic conidial cells, the main etiologic agent of CBM, were [Ag(phen)2]ClO4 and [Ag2(3,6,9-tdda)(phen)4].EtOH, (tdda: 3,6,9-trioxaundecanedioate), displaying MIC values equal to 1.2 and 0.6 µM, respectively. These complexes were effective in reducing the viability of F. pedrosoi biofilm formation and maturation. Silver(I)-tdda-phen, combined with itraconazole, reduced the viability and extracellular matrix during F. pedrosoi biofilm development. Moreover, both silver(I) complexes inhibited either metallo- or aspartic-type peptidase activities of F. pedrosoi as well as its conidia into mycelia transformation and melanin production. In addition, the complexes induced the production of intracellular reactive oxygen species in F. pedrosoi. Taken together, our data corroborate the antifungal action of metal-phen complexes, showing they represent a therapeutic option for fungal infections, including CBM.

Expanding the Toolbox for Functional Genomics in Fonsecaea pedrosoi: The Use of Split-Marker and Biolistic Transformation for Inactivation of Tryptophan Synthase (trpB) Gene

Chromoblastomycosis (CBM) is a disease caused by several dematiaceous fungi from different genera, and Fonsecaea is the most common which has been clinically isolated. Genetic transformation methods have recently been described; however, molecular tools for the functional study of genes have been scarcely reported for those fungi. In this work, we demonstrated that gene deletion and generation of the null mutant by homologous recombination are achievable for Fonsecaea pedrosoi by the use of two approaches: use of double-joint PCR for cassette construction, followed by delivery of the split-marker by biolistic transformation. Through in silico analyses, we identified that F. pedrosoi presents the complete enzymatic apparatus required for tryptophan (trp) biosynthesis. The gene encoding a tryptophan synthase trpB -which converts chorismate to trp-was disrupted. The ΔtrpB auxotrophic mutant can grow with external trp supply, but germination, viability of conidia, and radial growth are defective compared to the wild-type and reconstituted strains. The use of 5-FAA for selection of trp^- phenotypes and for counter-selection of strains carrying the trp gene was also demonstrated. The molecular tools for the functional study of genes, allied to the genetic information from genomic databases, significantly boost our understanding of the biology and pathogenicity of CBM causative agents.

Molecular epidemiology and clinical-laboratory aspects of chromoblastomycosis in Mato Grosso, Brazil

INTRODUCTION

Chromoblastomycosis is a disease caused by melanized fungi, primarily belonging to the genera Fonsecaea and Cladophialophora, mainly affecting individuals who are occupationally exposed to soil and plant products. This research aimed to determine the clinical, epidemiological and laboratory characteristics of chromoblastomycosis in the state of Mato Grosso, Brazil.

MATERIALS AND METHODS

Patients diagnosed with chromoblastomycosis treated at the Júlio Müller University Hospital, Cuiabá, Brazil, from January 2015 to December 2020, whose isolates were preserved in the Research Laboratory of the Faculty of Medicine of the Federal University of Mato Grosso. Isolates were identified by partly sequencing the Internal Transcribed Spacer (ITS) and β-tubulin (BT2) loci. AFLP fingerprinting was used to explore the genetic diversity. Susceptibility to itraconazole, voriconazole, 5-fluorocytosine, terbinafine and amphotericin B was determined by the broth microdilution technique.

RESULTS

Ten patients were included, nine were male (mean age = 64.1 years). Mean disease duration was 8.6 years. Lesions were mainly observed in the lower limbs. Predominant clinical forms were verrucous and scarring. Systemic arterial hypertension and type II diabetes mellitus were the predominant comorbidities. Leprosy was the main concomitant infectious disease. Fonsecaea pedrosoi was the unique aetiological agent identified with moderate genetic diversity (H = 0.3934-0.4527; PIC = 0.3160-0.3502). Antifungal agents with the highest activity were terbinafine, voriconazole and itraconazole.

CONCLUSION

Chromoblastomycosis is affecting the poor population in rural and urban areas, mainly related to agricultural activities, with F. pedrosoi being the dominant aetiologic agent. All isolates had low MICs for itraconazole, voriconazole and terbinafine, confirming their importance as therapeutic alternatives for chromoblastomycosis.

Inflammasome and Inflammatory Programmed Cell Death in Chromoblastomycosis

Chromoblastomycosis (CBM) is a chronic, progressive fungal disease of the skin and subcutaneous tissue caused by a group of dematiaceous fungi. Verrucous lesions present parasite-rich granulomas and predominance of a Th2 patterns of cytokines. The inflammasome constitutes a macromolecular protein complex that play a role in the activation of caspase 1 that cleaves pro-IL1β and pro-IL18, essential mediators of inflammation, and also activates pyroptosis. We intended to explore the presence and a possible role of inflammasome elements in cutaneous human lesions in CBM, considering the expression of IL1β, IL18, caspase 1, NLRP1, and also RIPK3, a key downstream component of necroptosis signaling. 35 skin biopsies of cutaneous lesions of verrucous form of CBM and 10 biopsies from normal skin were selected. The diagnosis was based on histological and clinical analysis. An immunohistochemical protocol was performed. The histopathological analysis evidenced epidermis with hyperkeratosis, irregular acanthosis, and micro abscesses. The dermis presented suppurative granulomas and inflammatory infiltrate composed by giant cells, macrophages, epithelioid cells, lymphocytes, and some eosinophils. Positive cells were distributed in the inflammatory infiltrate, with an increased number of cells expressing caspase 1, IL1β and IL18. Cells expressing RIPK3 and NLRP1 were less frequent. The intense presence of caspase 1, IL1β and IL18, allied to NLRP1 expression, suggest that inflammasome and pyroptosis could play a role in the immune response against fungal agents of CBM. Our results, allied to data from literature, could suggest that inflammasome-mediated response and pyroptosis could be a target to be explored to decrease CBM lesions.

Chromoblastomycosis: A case series from Eastern China

Chromoblastomycosis (CBM) is a chronic fungal infection of the cutaneous and subcutaneous tissues caused by brown pigmented fungi. Fonsecaea monophora is one of the most common pathogens of CBM in China. Most formal cases have been reported from Southern China, however, the infection is not uncommon in Eastern China where very few case series are available. To describe the clinical aspects of CBM, we report a series of 11 cases between 2018 and 2021 at a single medical center in Eastern China. The patients were predominately male (n = 9) and the disease duration ranged from 3 months to 20 years. Plaque type lesions were the most common clinical manifestations. There were 7 cases of mild forms and 3 cases of severe forms. Among the 3 severe cases, one case gave up treatment due to economic poverty; one case did not respond to a 1-year systemic treatmen; one case was cured by combination therapy of 10 months. Other cases were cured by treatment with antifungal agents. All cases of direct mycological examination were positive. All isolates were identified by morphology and sequencing of the the ITS regions of ribosomal DNA, Ten were F. monophora and 1 was Cladophialophora carrionii. All cases had been evaluated at other clinics, where 8 cases were misdiagnosed as other diseases. As a neglected tropical disease (NTD), CBM is still a major challenge in the field of dermatology, especially in its severe clinical forms. As an effective and simple diagnostic method of CBM, direct microscopic examination should be further promoted in rural hospitals.

Chromoblastomycosis is a neglected fungal disease that mainly affects low-income agricultural workers and rural population. The high misdiagnosis rate of chromoblastomycosis is a major challenge in dermatology, especially for rural hospitals. With the increase in the disease severity, infections may bring significant limitations to labor activities. Severe lesions tend to respond slowly or even become non-responding to antifungal drugs. A direct microscopic examination can find pathogens with typical characteristics; so, this technology must be promoted and mastered through short-term training in rural hospitals. The disease is an implantation mycosis, and therefore, wearing protective clothing and shoes are effective measures to prevent these diseases. The treatment choice and results depend on the patients’ lesion grade. Mild cases respond well to systemic agents, whereas high doses and a long treatment and combination therapy are the first treatment choices for severe forms. This study presents clinical features, mycological findings, pathogens, treatments, and outcomes of CBM from Zhejiang, Eastern China.

Annular infectious dermatoses

Annular configuration is conspicuous in the clinical manifestation of many skin diseases and can be helpful for the diagnosis and differential diagnosis. Variations may include arciform, ring-form, annular, circinate, serpiginous, gyrated, polycyclic, targeted or figurate forms, in different colors, sizes, and numbers, with various textures and surfaces. In infectious dermatoses, the annular reactions can be specific or nonspecific, while the underlying mechanisms remain largely unknown. In the specific reactions caused by direct invasion of the pathogens, the contest between the centrifugal outspread of the infectious agents and the centripetal impedance of the host immune response is supposed to determine the final conformation. Examples include erythema infectiosum, orf, erythema multiforme, and pityriasis rosea of viral origin. Bacterial infections that may display annular lesions include erythrasma, erythema (chronicum) migrans of Lyme borreliosis, secondary syphilis, cutaneous tuberculosis, and leprosy. Superficial mycosis, such as dermatophytosis, candida intertrigo, tinea imbricata, and subcutaneous mycosis, such as chromoblastomycosis, and algae infection protothecosis, are characterized by annular progression of the skin lesions. The creeping serpiginous extension is an alarming sign for the diagnosis of cutaneous larva migrans. A better understanding of the virulence and pathogenicity of the pathogens and the way and type of immune response will help to clarify the pathogenesis.

Diagnosis of Cutaneous Chromoblastomycosis and Its Response to Amphotericin B Therapy: A Case Report

Cutaneous chromoblastomycosis is a chronic subcutaneous fungal disease of the skin caused by Blastomyces dermatitidis, especially by Fonsecaea, Phialophora,and Cladophialophora species affecting the skin, lungs, intestines, stomach, and central nervous system. It is treated using itraconazole in mild cases and amphotericin B in severe cases. A six-year-old female child presented to the Dermatology Outpatient Department with pigmented brown to blackish tanned plaques and verrucous lesions on the face and extremities. These lesions were present for the past two and a half years and were slowly enlarging and involving other areas like the trunk. The lesions were proven on biopsy to be cutaneous blastomycosis. The patient was put on infusions of amphotericin B in a calculated pediatric dose. Her blood pressure and renal function tests were checked daily to avoid any electrolyte derangements, nephrotoxicity, and systemic infusion reactions caused by amphotericin B. Amphotericin B reduced the size of the cutaneous lesions, and treatment response was assessed on regular follow-ups. Chromoblastomycosis should be considered in the differential diagnosis to enable timely treatment and to prevent its lethal complications such as epidermoid carcinoma. Treatment should continue for two to three months until histopathology is negative to ensure complete eradication.

Pathogenicity and Growth Conditions Modulate Fonsecaea Extracellular Vesicles' Ability to Interact With Macrophages

Chromoblastomycosis (CBM) is a chronic cutaneous and subcutaneous mycosis caused by black, dimorphic, and filamentous fungi of the Herpothrichiellaceae family, such as species of the genus Fonsecaea. These fungi can switch between the saprophytic forms (conidia and hyphae) and the pathogenic form, the muriform cells (MCs), which is considered an essential mechanism for fungal virulence. Nearly all types of cells can produce membranous structures formed by a lipid bilayer that communicate extracellularly with other cells, known as “extracellular vesicles” (EVs), which may act as virulence factors, as observed for several species of pathogenic fungi. Our findings demonstrated for the first time that F. pedrosoi, F. nubica, and F. erecta produce EVs in response to nutritional conditions. The EVs varied in sterol and protein contents, size, and morphology. Moreover, the EVs induced different cytokine and nitric oxide release patterns by bone marrow-derived macrophages (BMDMs). The EVs activated IL-1β production, possibly acting as the first signal in inflammasome activation. Unlike the pathogenic species, the EVs isolated from F. erecta did not significantly stimulate TNF and IL-10 production in general. Overall, these results demonstrated that different species of Fonsecaea produce EVs capable of modulating pro- and anti-inflammatory cytokine and nitric oxide production by BMDMs and that growth conditions affected the immunomodulatory capacities of the EVs as well as their size, content, and morphology.

Photodynamic therapy, a promising treatment approach for cutaneous infectious granulomas

Cutaneous infectious granulomas are mainly caused by fungi and bacteria. Antibiotics are the primary therapeutic choices for the diseases, but the drug-resistant pathogens become increasingly prevalent. Thus, there is an urgent need to explore novel approaches to treating cutaneous infectious granulomas. Photodynamic therapy (PDT) is widely used as an alternative treatment for various kinds of skin diseases, and evidence has been accumulating that PDT is also effective for the treatment of cutaneous infectious granulomas. In this narrative review, we sought to summarize the recent literature concerning the applications and mechanisms of PDT in the treatment of cutaneous infectious granulomas. Clinical and basic research has demonstrated that PDT is an effective approach in treating fungal infections such as sporotrichosis and chromoblastomycosis. In addition, PDT is also used to treat atypical mycobacterial infections such as Mycobacterium marinum. PDT can significantly shorten the duration of antibiotics treatment, resulting in diminishment of adverse effects. The potential mechanisms of PDT are to kill the pathogens directly or elicit modulatory effects on the immune microenvironments. We conclude that PDT is a promising therapeutic choice for the treatment of cutaneous infectious granulomas.

Accuracy of direct examination and culture as compared to the anatomopathological examination for the diagnosis of chromoblastomycosis: a systematic review

Background

Chromoblastomycosis is a skin infection caused by dematiaceous fungi that take the form of muriform cells in the tissue. It mainly manifests as verrucous plaques on the lower limbs of rural workers in tropical countries.

Objectives

The primary objective of this review is to evaluate the accuracy of diagnostic methods for the identification of chromoblastomycosis, considering the histopathological examination as the reference test.

Methods

MEDLINE, LILACS and Scielo databases were consulted using the terms “chromoblastomycosis” AND “diagnosis”. The eligibility criteria were: studies that evaluated the accuracy of tests for the diagnosis of chromoblastomycosis. Eleven studies were selected. Statistical analysis included the calculation of sensitivity and specificity of the diagnostic methods.

Results

Considering the histopathological examination as the reference test, the culture showed a sensitivity (S) of 37.5% - 90.9% and a specificity (Sp) of 100%; while direct mycological examination showed S =  50% - 91.6% and Sp of 100% . Considering the culture as the reference test, the serology (precipitation techniques) showed S  of 36% - 99%; and Sp  of 80% - 100%; while the intradermal test showed S  of 83.3% - 100% and Sp  of 99.4% - 100%.

Study limitations

The small number of studies and very discrepant sensitivity results among them do not allow the calculation of summary measures through a meta-analysis.

Conclusions

Direct mycological examination, culture, intradermal test and serology show sensitivity and specificity values ​​for the diagnosis of chromoblastomycosis with no significant difference between the studies.

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.

Road map to the treatment of neglected tropical diseases: Nanocarriers interventions

Neglected tropical disease (NTD) is a set of 20 deadliest endemic diseases which shows its presence in most of the developing countries worldwide. Nearly 1 billion of the population are affected by it and suffered from poverty yearly. These diseases offer their own unique challenges and limitations towards effective prevention and treatment methods. Neglected tropical diseases are severe infections they may not kill the patient but debilitate the patient by causing severe skin deformities, disfigurement and horrible risks for several infections. Existing therapies for neglected diseases suffer from the loopholes like high degree of toxicity, side effects, low bioavailability, improper targeting and problematic application for affected populations. Progress in the field of nanotechnology in last decades suggested the intervention of nanocarriers to take over and drive the research and development to the next level by incorporating established drugs into the nanocarriers rather than discovering the newer drugs which is an expensive affair. These nanocarriers are believed to be a sure shot technique to fight infections at root level by virtue of its nanosize and ability to reach at cellular level. This article highlights the recent advances, rationale, targets and the challenges that are being faced to fight against NTDs and how the novel therapy tactics are able to contribute to its importance in prevention and treatment of NTDs.

Neutrophil-suppressive activity over T-cell proliferation and fungal clearance in a murine model of Fonsecaea pedrosoi infection

Neutrophils are essential to control several fungal infections. These cells are commonly known for their pro-inflammatory activities. However, some studies have demonstrated the anti-inflammatory properties of neutrophils during certain infectious diseases, culminating in the inhibition of T cell proliferation. Chromoblastomycosis (CBM) is a deep and progressive mycosis that affects thousands of people worldwide. Although neutrophil infiltrates are observed in the lesion histopathology, the fungus can overtake the immune system response and destroy the host-infected tissue. The present study demonstrated that neutropenic animals had an increase in the IL-6 production in the spleen and liver, followed by a lower fungal burden in these organs up to 14 days of infection. Neutropenic animals also showed a lower F. pedrosoi-specific antibody production 14-days post infection and higher T-cell proliferation in the in vitro experiments after stimulation with F. pedrosoi-purified proteins. Taken together, our results suggest that the presence of regulatory neutrophils in the mouse model of F. pedrosoi infection could act favoring the spread of the fungus and the chronicity of the infection. These findings shed light on the CBM treatment, which might target neutrophil polarization as a new therapy approach to treat CBM lesions.

Chromoblastomycosis in Latin America and the Caribbean: epidemiology over the past 50 years

Chromoblastomycosis is a chronic disease caused by melanized fungi that mainly affect individuals performing soil-related labour. The objective of this study was to analyse the epidemiological and clinical characteristics of chromoblastomycosis in Latin America and the Caribbean by an extensive literature review. An integrative review was performed of English, French, Portuguese, and Spanish publications in LILACS, SciELO, PubMed, SCOPUS and Web of Science databases covering the period 1969-2019. A total of 1,211 articles were identified, of which 132 were included in the review, covering 2,081 patients, 80.3% were male, the mean age was 56.1 years. The mean duration of the disease was 10.8 years. The lesions were mainly described in the lower limbs (60%). The most frequent clinical forms were verrucous (46.4%) and tumorous (21.7%). Major disease symptoms and signs consisted of itching and pain. Bacterial infection and functional limitation were important complications. Immunosuppression post-kidney transplantation was the most frequent comorbidity while leprosy was the main concomitant infectious disease. Fonsecaea pedrosoi and Cladophialophora carrionii were the predominant etiological agents. Majority of the cured cases were treated with itraconazole as monotherapy or in combination with other antifungals, surgery or cryosurgery. Chromoblastomycosis affects hundreds of rural workers in Latin America and the Caribbean, causing disability and personal, family and economic losses. It is important to prioritize epidemiological surveillance and early diagnosis of this disease in order to reveal its real prevalence and direct resources to preventive actions, diagnosis and early treatment.

LAY SUMMARY

Chromoblastomycosis is a slowly progressing chronic disease caused by melanized fungi. We collected data from South America and the Caribbean covering 1969-2019, the 132 articles included 2 081 patients, mean disease duration was 10.8 years. Fonsecaea pedrosoi and Cladophialophora carrionii predominated.

Managing chromoblastomycosis with acitretin plus imiquimod: A case report on the improvement of cutaneous lesions and reduction of the treatment time

Chromoblastomycosis (CBM) is an infectious disease caused by fungi that is prevalent in tropical and subtropical countries. Besides few therapeutic options, the classical treatment of CBM needs to be administrated for a long period of time, and unfortunately some patients do not show improvement of the lesions. Thus, it becomes urgent to develop new strategies for the treatment of CBM. This work reports a successful treatment, performed with the combination of oral acitretin (50 mg/kg, once a day) plus topical imiquimod (50 mg/g, five times per week) for 5 months in a patient with CBM. A significant improvement of the lesions was observed in the 1st month, and in the 5th a complete regression of lesions was recorded. Changes in the biochemical parameters were not observed. These data suggest that the combination of acitretin and imiquimod may be effective at treating CBM.

Retinoids in Fungal Infections: From Bench to Bedside

Retinoids-a class of chemical compounds derived from vitamin A or chemically related to it-are used especially in dermatology, oncohematology and infectious diseases. It has been shown that retinoids-from their first generation-exert a potent antimicrobial activity against a wide range of pathogens, including bacteria, fungi and viruses. In this review, we summarize current evidence on retinoids' efficacy as antifungal agents. Studies were identified by searching electronic databases (MEDLINE, EMBASE, PubMed, Cochrane, Trials.gov) and reference lists of respective articles from 1946 to today. Only articles published in the English language were included. A total of thirty-nine articles were found according to the criteria. In this regard, to date, In vitro and In vivo studies have demonstrated the efficacy of retinoids against a broad-spectrum of human opportunistic fungal pathogens, including yeast fungi that normally colonize the skin and mucosal surfaces of humans such as Candida spp., Rhodotorula mucilaginosa and Malassezia furfur, as well as environmental moulds such as Aspergillus spp., Fonsecae monofora and many species of dermatophytes associated with fungal infections both in humans and animals. Notwithstanding a lack of double-blind clinical trials, the efficacy, tolerability and safety profile of retinoids have been demonstrated against localized and systemic fungal infections.

Cyphellophora laciniata: A new etiological agent of chromoblastomycosis

Chromoblastomycosis is a chronic subcutaneous mycosis caused by traumatic inoculation of dematiaceous fungi especially in tropical and subtropical areas. Cyphellophora genus include melanized fungi reported as etiological agents of skin and nail infections. We report a 60-year-old male from the south of Mexico with a 40-year history of chromoblastomycosis caused by Cyphellophora laciniata. The isolated fungus was identified by sequencing of the internal transcribed spacer region of rDNA. The patient was treated with itraconazole and cryosurgery with unsatisfactory results.

Chromoblastomycosis evolving to sarcomatoid squamous cell carcinoma: A case report

Chromoblastomycosis (CMB) is a cutaneous fungal infection caused by dematiaceous fungi. According to the World Health Organization CMB has been elected as a tropical disease, and it is prevalent in tropical and subtropical regions. The lower extremities are the most affected areas, and the lesions progress with erythema, papules, nodules, verrucose plates and/or ulcerations. So far, few works have demonstrated neoplastic transformation in chronic CMB lesions, and it may be a consequence of prolonged inflammatory response. In the present case report, we described a neoplastic transformation from CMB lesion of a 55- year-old man, presenting lesions only in the left leg for 35 years. After treatment, a verrucous white plate with thick and irregular borders emerged in the ankle, which was identified as a sarcomatoid squamous cell carcinoma. The present case report highlights the importance of an early diagnosis and treatment.

A diffuse granulomatous inflammation secondary to a trauma of hand: a case report

Granulomatous inflammation is rare in the musculoskeletal system and difficult to diagnose. Here we describe a case of a 62-year-old woman with a history of being stabbed by a fishbone presented with a soreness, swelling, and limitation of movement of her right palm and wrist for 4 months. Surgery was done and the histopathology of specimens demonstrated granulomatous lesion, which was negative for acid-fast bacilli. This case demonstrates the diagnosis of granulomatous tenosynovitis on MRI, ultrasound, and surgical examination under anesthesia.

Presence of hyphae in chromoblastomycosis examinations: an enigma to be solved

The detection of muriform cells in direct mycological or anatomopathological examination is considered pathognomonic for chromoblastomycosis. The morphological aspect that these fungal structures acquire were called “Borelli spiders”, when associated with hyphae. Reports of this association have been described for decades, initially related to more pathogenic agents of this mycosis. More recent studies have shown aspects related to the host's immunity that participate in this process, as well as an association with a worse disease prognosis. The present study discloses the findings of complementary examinations with the presence of “Borelli’s spiders” in a patient diagnosed with chromoblastomycosis.

Silver(I) and Copper(II) Complexes of 1,10-Phenanthroline-5,6-Dione Against Phialophora verrucosa: A Focus on the Interaction With Human Macrophages and Galleria mellonella Larvae

Phialophora verrucosa is a dematiaceous fungus that causes mainly chromoblastomycosis, but also disseminated infections such as phaeohyphomycosis and mycetoma. These diseases are extremely hard to treat and often refractory to current antifungal therapies. In this work, we have evaluated the effect of 1,10-phenanthroline-5,6-dione (phendione) and its metal-based complexes, [Ag (phendione)2]ClO4 and [Cu(phendione)3](ClO4)2.4H2O, against P. verrucosa, focusing on (i) conidial viability when combined with amphotericin B (AmB); (ii) biofilm formation and disarticulation events; (iii) in vitro interaction with human macrophages; and (iv) in vivo infection of Galleria mellonella larvae. The combination of AmB with each of the test compounds promoted the additive inhibition of P. verrucosa growth, as judged by the checkerboard assay. During the biofilm formation process over polystyrene surface, sub-minimum inhibitory concentrations (MIC) of phendione and its silver(I) and copper(II) complexes were able to reduce biomass and extracellular matrix production. Moreover, a mature biofilm treated with high concentrations of the test compounds diminished biofilm viability in a concentration-dependent manner. Pre-treatment of conidial cells with the test compounds did not alter the percentage of infected THP-1 macrophages; however, [Ag(phendione)2]ClO4 caused a significant reduction in the number of intracellular fungal cells compared to the untreated system. In addition, the killing process was significantly enhanced by post-treatment of infected macrophages with the test compounds. P. verrucosa induced a typically cell density-dependent effect on G. mellonella larvae death after 7 days of infection. Interestingly, exposure to the silver(I) complex protected the larvae from P. verrucosa infection. Collectively, the results corroborate the promising therapeutic potential of phendione-based drugs against fungal infections, including those caused by P. verrucosa.

Deep mycoses and pseudomycoses of the foot: a single-center retrospective study of 160 cases, in a tertiary-care center in Mexico

BACKGROUND

Deep mycoses and pseudomycoses (DMP) may cause significant disability and even death; however, the reports regarding these diseases, mainly affecting the foot, are scarce.

OBJECTIVE

To describe the epidemiological, clinical, and diagnostic characteristics of DMP of the foot in 160 patients.

METHODS

A retrospective and observational study of DMP affecting the foot was carried out in a tertiary-care center in Mexico for 20 years (from January 2000 to December 2019). Cases with confirmatory microbiological studies were included; the identification of the isolated fungi was based on the forms of reproduction. For actinomycetes, morphological analysis in an automated system ATB Vitek® 1574 (Biomèrieux) was used. The fungi were identified by PCR, using several primers from the ITS regions and for actinomycetes in the 16S rRNA region. Data from histopathological studies were also collected.

RESULTS

One hundred and sixty proven cases of DMP of the foot were included. The cases were categorized into nine types of infections including mycetoma (actinomycetoma and eumycetoma) in 102 cases (63.7%); sporotrichosis in 21 cases (13.1%); chromoblastomycosis, 18 cases (11.2%); phaeohyphomycosis, 3 cases (1.8%); histoplasmosis, 12 cases (7.5%); coccidioidomycosis 2 cases (1.2%) and botryomycosis and nocardiosis with one case respectively (0.6%). Most cases developed after traumatic implantation (147 cases, 91.8%). One hundred fifteen cases (71.8%) were men. The evolution was chronic in 125 cases (78.2%); bone involvement was observed in 64 cases (40%). Parasitic forms were observed In 139 cases (86.8%). The isolation and identification of the etiological agents were confirmed in all cases.

CONCLUSION

The main DMP affecting the foot were infections due to traumatic implantation; most were endemic mycoses. The clinical characteristics and the evolution of the diseases are easily misdiagnosed, and thus, diagnostic tests are usually required.

Case Report: Treatment of Chromoblastomycosis with Combinations including Acitretin: A Report of Two Cases

Chromoblastomycosis is a cutaneous fungal infection caused by dematiaceous fungi that belong to the order Chaetothyriales and family Herpotrichiellaceae. This infection is prevalent in tropical and subtropical areas and has been designated as a neglected tropical disease according to the WHO. Chromoblastomycosis infection is difficult to treat, and there are limited therapeutic options, making urgent the characterization of new medicines or approaches to treat such infection. In the present case report, two patients with extensive chromoblastomycosis lesions were treated with the combination of itraconazole, acitretin, and imiquimod. In the fourth month of treatment, both patients showed improvement of verrucous plates, suggesting that acitretin combined with drugs already used in chromoblastomycosis therapy can decrease the time of treatment, improving patient's quality of life.