Endogenous fungal endophthalmitis caused by Cladophialophora devriesii: report of a case and literature review

PURPOSE

To report a case of endogenous endophthalmitis caused by the dematiaceous fungus Cladophialophora devriesii.

METHODS

Observational case report and literature review.

CASE PRESENTATION

A 73-year-old female with a history of chronic obstructive pulmonary disease presented with a red and painful left eye. Examination revealed anterior segment inflammation and vitritis, indicative of endophthalmitis. She underwent core vitrectomy and intravitreal injection of vancomycin and amphotericin B. The vitreous sample showed inflammatory cells and fungal hyphae, and systemic amphotericin B and itraconazole were commenced for fungal endophthalmitis. Targeted amplification of the sample for bacterial DNA (V2-V3 region of 16 S rDNA) was negative, but fungal DNA targets (ITS1 and ITS2) were present, and their sequences were consistent with Cladophialophora devriesii. Phenotypic characterisation and sequencing of ITS1 and ITS2, carried out on cultured fungus from the sample, also revealed Cladophialophora devriesii. She received repeated intravitreal injections of voriconazole, and based on the antifungal susceptibility results, her systemic medication was changed to posaconazole. After 12 months, the eye showed no signs of inflammation, and posaconazole therapy was discontinued. After 3 months without antifungal medication, the inflammation recurred, and she was restarted on antifungal therapy for an additional 20 months. Another recurrence occurred 3 months after discontinuation of treatment, and a repeat vitreous sample confirmed the presence of Cladophialophora devriesii. She was started on isavuconazole, but developed seclusio pupillae and painful secondary glaucoma. Due to the duration and severity of the infection, the eye was enucleated. Histopathology revealed persistent fungal elements at the ciliary processes and the posterior lens surface.

CONCLUSIONS

This second reported case of endogenous endophthalmitis caused by Cladophialophora devriesii illustrates the role of vitreous sampling and molecular methods in diagnosis and treatment of fungal endophthalmitis. Despite early diagnosis and prolonged local and systemic antifungal therapy, it was not possible to achieve long-term control of the fungal infection.

Chromoblastomycosis: A Case Series and Literature Review

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

Iron Starvation Induces Ferricrocin Production and the Reductive Iron Acquisition System in the Chromoblastomycosis Agent Cladophialophora carrionii

Iron is a micronutrient required by almost all living organisms. Despite being essential, the availability of this metal is low in aerobic environments. Additionally, mammalian hosts evolved strategies to restrict iron from invading microorganisms. In this scenario, the survival of pathogenic fungi depends on high-affinity iron uptake mechanisms. Here, we show that the production of siderophores and the reductive iron acquisition system (RIA) are employed by Cladophialophora carrionii under iron restriction. This black fungus is one of the causative agents of chromoblastomycosis, a neglected subcutaneous tropical disease. Siderophore biosynthesis genes are arranged in clusters and, interestingly, two RIA systems are present in the genome. Orthologs of putative siderophore transporters were identified as well. Iron starvation regulates the expression of genes related to both siderophore production and RIA systems, as well as of two transcription factors that regulate iron homeostasis in fungi. A chrome azurol S assay demonstrated the secretion of hydroxamate-type siderophores, which were further identified via RP-HPLC and mass spectrometry as ferricrocin. An analysis of cell extracts also revealed ferricrocin as an intracellular siderophore. The presence of active high-affinity iron acquisition systems may surely contribute to fungal survival during infection.

Dermatopathology and the Diagnosis of Fungal Infections

Diagnosis of superficial/cutaneous fungal infections from skin, hair and nail samples is generally achieved using microscopy and culture in a microbiology laboratory, however, any presentation that is unusual or subcutaneous is sampled by taking a biopsy. Using histological techniques a tissue biopsy enables a pathologist to perform a full examination of the skin structure, detect any inflammatory processes or the presence of an infectious agent or foreign body. Histopathological examination can give a presumptive diagnosis while a culture result is pending, and may provide valuable diagnostic information if culture fails. This review demonstrates how histopathology contributes to the diagnosis of fungal infections from the superficial to the life threatening.

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.

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.

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.

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.

A Rare Case of Chromoblastomycosis Resembling Keloid in an Indonesian Child

Chromoblastomycosis (CBM) is a rare chronic fungal infection caused by various dematiaceous fungi. This mycosis is mostly found in middle-aged males in tropical and subtropical countries. Only few cases of CBM in children have been reported. The diagnosis of CBM is often delayed due to the similarities with other dermatological diseases, such as cutaneous tuberculosis, mycetoma, leprosy, viral warts, psoriasis vulgaris, or malignancies. We report a case of an 11-year-old healthy boy having CBM. On his left knee, there were large erythematous plaques and tumors with scaly surfaces, some lesions appeared to be cauliflower-like. The patient denied pain and pruritus. The preliminary diagnosis was keloid; however, histopathological findings led to the final diagnosis, which was established as CBM. The patient was treated with oral itraconazole 100 mg daily. His lesions partially resolved within one month of treatment. Although uncommon in children, the differential diagnosis of CBM must be considered in any suspicious lesion(s). Itraconazole 100 mg daily gave a good response in children with CBM. Accurate diagnosis and early treatment are needed to achieve successful management of CBM in children.

Muriform Cells Can Reproduce by Dividing in an Athymic Murine Model of Chromoblastomycosis due to Fonsecaea pedrosoi

Transformation of Fonsecaea pedrosoi into muriform cells enhances the resistance against phagocytosis and elimination by host immune cells, and links to the chronicity of chromoblastomycosis. Here, we aim to determine whether the muriform cells can reproduce in tissue without reverse transformation into hyphal form by using an experimental nu/nu-BALB/c mouse model of chromoblastomycosis due to F. pedrosoi. During the whole 81-day observation period, most of the hyphal inocula had transformed into muriform cells at 75 days postinoculation and maintained as this parasitic morphology till 81 days postinoculation simultaneously with increased fungal loads in tissue and the worsening of footpad lesion. Scanning and transmitting electronic microscope examinations showed that the muriform cells obtained in tissue or induced in vitro can reproduce daughter cells by dividing, and, meanwhile, the daughter cells had the potential to produce buds and grow into hyphae reversely. Furthermore, exoenzyme examination suggested that the profile of exoenzymes constituted by muriform cells was quite different from that constituted by hyphae although the assay showed both of them had obvious metabolic activity. By contrast, most muriform cells in the footpad gradually transformed into the elongated hyphae without obvious infiltration of inflammatory cells during repeated intraperitoneal administration of cyclophosphamide (50 mg/kg, per every other day) from 50 to 80 days postinoculation. Therefore, we infer that F. pedrosoi can reproduce by dividing as muriform cells in mouse tissue, and the morphological transformation between hyphal form and muriform cells is possibly associated with the host immune status.

Early immune response against Fonsecaea pedrosoi requires Dectin-2-mediated Th17 activity, whereas Th1 response, aided by Treg cells, is crucial for fungal clearance in later stage of experimental chromoblastomycosis

Chromoblastomycosis (CBM) is a chronic worldwide subcutaneous mycosis, caused by several dimorphic, pigmented dematiaceous fungi. It is difficult to treat patients with the disease, mainly because of its recalcitrant nature. The correct activation of host immune response is critical to avoid fungal persistence in the tissue and disease chronification. CD4+ T cells are crucial for the development of protective immunity to F. pedrosoi infection. Here, we investigated T helper cell response dynamics during experimental CBM. Following footpad injection with F. pedrosoi hyphae and conidia, T cells were skewed towards a Th17 and Th1 phenotype. The Th17 population was the main Th cell subset found in the infected area during the early stages of experimental murine CBM, followed by Th1 predominance in the later stages, coinciding with the remission phase of the disease in this experimental model. Depletion of CD25+ cells, which leads to a reduction of Treg cells in the draining lymph node, resulted in decline in fungal burden after 14 days of infection. However, fungal cells were not cleared in the later stages of the disease, prolonging CBM clinical features in those animals. IL-17A and IFN-γ neutralization hindered fungal cell elimination in the course of the disease. Similarly, in dectin-2 KO animals, Th17 contraction in the course of experimental CBM was accompanied by fungal burden decrease in the first 14 days of infection, although it did not affect disease resolution. In this study, we gained insight into T helper subsets' dynamics following footpad injections of F. pedrosoi propagules and uncovered their contribution to disease resolution. The Th17 population proved to be important in eliminating fungal cells in the early stages of infection. The Th1 population, in turn, closely assisted by Treg cells, proved to be relevant not only in the elimination of fungal cells at the beginning of infection but also essential for their complete elimination in later stages of the disease in a mouse experimental model of CBM.

A case of mycetoma-like chromoblastomycosis in Qatar

Chromoblastomycosis is one of the neglected tropical mycoses associated with chronic infection of the skin and subcutaneous tissues. We report a case of 49-year-old patient originally from India presented with a mycetoma-like lesion in his right foot which was slowly progressing over three-year period. The diagnosis of chromoblastomycosis was confirmed following surgical excision and identification of the unique histological pathology of muriform bodies. The patient was subsequently treated with a prolonged course of oral itraconazole with a favorable outcome. The clinical presentations, assessment and management of the disease are outlined.

Effect of Fonsecaea monophora on the Polarization of THP-1 Cells to Macrophages

BACKGROUND

Chromoblastomycosis is a chronic, progressive fungal disease of the skin and subcutaneous tissue caused by a unique group of dematiaceous fungi. Fonsecaea monophora, a new species distinct from Fonsecaea pedrosoi strains, is the main pathogen responsible for chromoblastomycosis in south China. Macrophages can be polarized into two categories: classically activated and alternatively activated.

OBJECTIVES

Little is known about the relationship between F. monophora and macrophage polarization. This study aimed to study the effect of F. monophora on the polarization of THP-1 cells to macrophages.

METHODS

We established coculture systems of F. monophora and THP-1-derived macrophages in different activation states.

RESULTS

F. monophora enhanced the phagocytosis by macrophages in the initially activated state and weakened the phagocytosis by classically activated macrophages without affecting that by alternatively activated macrophages. Classically activated macrophages had the strongest killing effect on F. monophora, while the initially activated macrophages had the weakest. The pathogen could not be rapidly cleared by any type of macrophage. F. monophora promoted the expression of proinflammatory cytokines and inhibited that of anti-inflammatory cytokines.

CONCLUSIONS

F. monophora promoted the polarization of THP-1 cells to classically activated macrophages and inhibited that of THP-1 cells to alternatively activated macrophages.

Fonsecaea pedrosoi Conidia Induces Activation of Dendritic Cells and Increases CD11c+ Cells in Regional Lymph Nodes During Experimental Chromoblastomycosis

The chromoblastomycosis is a subcutaneous mycosis with a high morbidity rate, Fonsecaea pedrosoi being the largest etiologic agent of this mycosis, usually confined to the skin and subcutaneous tissues. Rarely people get the cure, because the therapies shown to be deficient and few studies report the host-parasite relationship. Dendritic cells (DCs) are specialized in presenting antigens to naïve T lymphocytes inducing primary immune responses. Therefore, we propose to study the migratory capacity of DCs after infection with conidia of F. pedrosoi. The phenotype of DCs was evaluated using cells obtained from footpad and lymph nodes of BALB/c mice after 12, 24 and 72 h of infection. After 24 and 72 h of infection, we found a significant decrease in DCs in footpad and a significant increase in the lymph nodes after 72 h. The expression of surface markers and co-stimulatory molecules were reduced in cells obtained from footpad. To better assess the migratory capacity of DCs migration from footpad, CFSE-stained conidia were injected subcutaneously. We found that after 12 and 72 h, CD11c⁺ cells were increased in regional lymph nodes, leading us to believe that DCs (CD11c⁺) were able to phagocytic conidia present in footpad and migrated to regional lymph nodes.

Successful treatment of chromoblastomycosis caused by Fonsecaea pedrosoi using imiquimod

Chromoblastomycosis (CBM) is a fungal infection caused by fungi belonging to the order Chaetothyriales, and caused mainly by Fonsecaea pedrosoi. The classic treatment, based on itraconazole and/or terbinafine as well as physical approaches, is considered complex and ineffective due to the high rate of relapses. Thus, new strategies are needed to manage CBM; in this regard, the present work reports the evolution of lesions in patients successfully treated with imiquimod. Of note, classic treatment was not effective in healing the lesions of two of them, but single topical treatment with imiquimod healed the lesions.

Chromoblastomycosis Caused by Phialophora verrucosa in a Costa Rican Child with Skin Sequelae due to Snake Bite

Chromoblastomycosis is an implantation mycosis occurring among adults working in farms or with soil in tropical and subtropical areas worldwide. Fonsecaea pedrosoi is the most important agent in the tropical areas, while Phialophora verrucosa, although not a predominant agent, is found in the lowlands under the same conditions as the Fonsecae species.

We present the case of a 10-year-old aboriginal boy, belonging to a soil worker family, with a history of extensive leg lesions and lymphedema secondary to a snake bite five years earlier. He was admitted to the National Children's Hospital (part of the Caja Costarricense del Seguro Social: the social security system in Costa Rica) with multiple verrucous confluent lesions on the ankle, some with dark coloration, and no other symptoms. Clinical suspicion of chromoblastomycosis was made and later confirmed by culture. Itraconazole was started showing clinical improvement.

Chromomycosis, especially in the population with skin lesions or chronic tissue compromise, associated with the location and macroscopic findings, must be a part of our differential diagnosis. The story of an exposed pediatric patient to soil work and the history of an important leg swelling and skin disruption as sequelae of snake bite envenomation made this case unique. To our knowledge, there are no pediatric reports of Chromoblastomycosis in Latin America.

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.

Transformation of Fonsecaea pedrosoi into sclerotic cells links to the refractoriness of experimental chromoblastomycosis in BALB/c mice via a mechanism involving a chitin-induced impairment of IFN-γ production

Fonsecaea pedrosoi (F. pedrosoi) is the most common agent of chromoblastomycosis. Transformation of this fungus from its saprophytic phase into pathogenic sclerotic cells in tissue is an essential link to the refractoriness of this infection. Experimental studies in murine models have shown that the absence of CD4+ T cells impairs host defense against F. pedrosoi infection. Clinical research has also suggested that a relatively low level of the Th1 cytokine INF-γ and inefficient T cell proliferation are simultaneously present in patients with severe chromoblastomycosis upon in vitro stimulation with ChromoAg, an antigen prepared from F. pedrosoi. In the present study, we show that in mice intraperitoneally infected with F. pedrosoi-spores, -hyphae or in vitro-induced sclerotic cells respectively, the transformation of this causative agent into sclerotic cells contributes to a compromised Th1 cytokine production in the earlier stage of infection with impaired generation of neutrophil reactive oxygen species (ROS) and pan-inhibition of Th1/Th2/Th17 cytokine production with disseminated infection in the later stage by using a CBA murine Th1/Th2/Th17 cytokine kit. In addition, we have further demonstrated that intraperitoneal administration of recombinant mouse IFN-γ (rmIFN-γ) effectively reduces the fungal load in the infected mouse spleen, and dampens the peritoneal dissemination of F. pedrosoi-sclerotic cells. Meanwhile, exogeneous rmIFN-γ contributes to the formation and maintenance of micro-abscess and restores the decrease in neutrophil ROS generation in the mouse spleen infected with F. pedrosoi-sclerotic cells. Of note, we have once again demonstrated that it is a chitin-like component, but not β-glucans or mannose moiety, that exclusively accumulates on the outer cell wall of F. pedrosoi-sclerotic cells which were induced in vitro or isolated from the spleens of intraperitoneally infected BALB/c mice. In addition, our results indicate that decreased accumulation of chitin on the surface of live F. pedrosoi-sclerotic cells after chitinase treatment can be self-compensated in a time-dependent manner. Importantly, we have for the first time demonstrated that exclusive accumulation of chitin on the transformed sclerotic cells of F. pedrosoi is involved in an impaired murine Th1 cytokine profile, therefore promoting the refractoriness of experimental murine chromoblastomycosis.

Chromoblastomycosis in India: Review of 169 cases

Chromoblastomycosis (CBM) is a chronic, progressive, cutaneous and subcutaneous fungal infection following the traumatic implantation of certain dematiaceous fungi. The disease has worldwide prevalence with predominant cases reported from humid tropical and subtropical regions of America, Asia, and Africa. Diagnosis is often delayed or misdirected either due to poor degree of clinical suspicions or clinical simulation of dermatological conditions. The infection is not uncommon in India and several case reports from the sub-Himalayan belt and western and eastern coasts of India have been published; however, very few have reviewed the cases. We reviewed 169 cases published in English literature from India during 1957 through May 2016, including 2 recent cases from our institute. A tremendous increase in the number of reported cases was noticed since 2012, since which, more than 50% of the cases had been published. A majority of the patients (74.1%) were involved in various agricultural activities directly or indirectly. The mean age at presentation was 43.3 years ± 16.0, with male to female ratio of 4.2:1. The duration of disease at the time of presentation varied from 20 days to 35 years. Any history of trauma was recalled only in 33.8% of the studied cases. The lower extremity was the most common site afflicted, followed by the upper extremity. The culture was positive in 80.3% of the cases with Fonsecaea pedrosoi, isolated as the most common fungal pathogen, followed by Cladophialophora carrionii. Although all the commercially available antifungals were prescribed in these cases, itraconazole and terbinafine were the most commonly used, either alone or in combination with other drugs/physical methods, with variable degrees of outcome. Combinations of different treatment modalities (chemotherapy and physical methods) yielded a cure rate of 86.3%. CBM is refractory to treatment and no single antifungal agent or regimen has demonstrated satisfactory results. Increased awareness with early clinical suspicion of the disease and adequate therapy are necessary to improve the outcome. However, depending upon the causative agent, disease severity, and the choice of antifungals, variable outcomes can be observed.

Modulation of the immune response by Fonsecaea pedrosoi morphotypes in the course of experimental chromoblastomycosis and their role on inflammatory response chronicity

A common theme across multiple fungal pathogens is their ability to impair the establishment of a protective immune response. Although early inflammation is beneficial in containing the infection, an uncontrolled inflammatory response is detrimental and may eventually oppose disease eradication. Chromoblastomycosis (CBM), a cutaneous and subcutaneous mycosis, caused by dematiaceous fungi, is capable of inducing a chronic inflammatory response. Muriform cells, the parasitic form of Fonsecaea pedrosoi, are highly prevalent in infected tissues, especially in long-standing lesions. In this study we show that hyphae and muriform cells are able to establish a murine CBM with skin lesions and histopathological aspects similar to that found in humans, with muriform cells being the most persistent fungal form, whereas mice infected with conidia do not reach the chronic phase of the disease. Moreover, in injured tissue the presence of hyphae and especially muriform cells, but not conidia, is correlated with intense production of pro-inflammatory cytokines in vivo. High-throughput RNA sequencing analysis (RNA-Seq) performed at early time points showed a strong up-regulation of genes related to fungal recognition, cell migration, inflammation, apoptosis and phagocytosis in macrophages exposed in vitro to muriform cells, but not conidia. We also demonstrate that only muriform cells required FcγR and Dectin-1 recognition to be internalized in vitro, and this is the main fungal form responsible for the intense inflammatory pattern observed in CBM, clarifying the chronic inflammatory reaction observed in most patients. Furthermore, our findings reveal two different fungal-host interaction strategies according to fungal morphotype, highlighting fungal dimorphism as an important key in understanding the bipolar nature of inflammatory response in fungal infections.

Fonsecaea pedrosoi-induced Th17-cell differentiation in mice is fostered by Dectin-2 and suppressed by Mincle recognition

Chromoblastomycosis is a chronic skin infection caused by the pigmented saprophytic mould Fonsecaea pedrosoi. Chronicity of infection can be broken by a coordinated innate recognition of the spores by pattern recognition receptors. While Mincle signaling via the Syk/Card9 pathway is required for fungal recognition by host cells, it is not sufficient for host control. Exogenously applied TLR agonists are necessary to promote the induction of proinflammatory cytokines and clearance of infection in vivo. Here, we investigated whether costimulation by TLR agonists fosters the development of adaptive immune responses, by examining the development of fungus‐specific T cells. Subcutaneous infection of mice with F. pedrosoi spores induced the activation, expansion, and differentiation of Ag‐specific CD4⁺ T cells but TLR costimulation did not further augment these T‐cell responses. The Dectin‐2/FcRγ/Card9 signaling pathway promoted the differentiation of fungus‐specific CD4⁺ T cells into Th17 cells, whereas Mincle inhibited the development of this T‐helper subset in infected mice. These results indicate differential roles for Dectin‐2 and Mincle in the generation of adaptive immune responses to F. pedrosoi infection.

Clinical and demographic profile of chromoblastomycosis in a referral service in the midwest of São Paulo state (Brazil)

Chromoblastomycosis is one of the most frequent deep mycoses found in rural populations. This cross-sectional, retrospective and descriptive study was conducted with cases of chromoblastomycosis diagnosed throughout 20 years. A higher prevalence was observed among White male rural workers, with an average age of 59.69 years. Median time between onset of symptoms and diagnosis was 156 months. Lesions were predominantly located on the lower limbs; 34% of cases reported previous trauma. The most common associated symptoms were itching, pain and burning sensation. Mycological examination was positive in 91% of cases and Fonsecaea pedrosoi was the most prevalent etiologic agent.

Chromoblastomycosis in a Diabetic Patient Without a History of Trauma

Chromoblastomycosis (CBM) is a slowly progressive cutaneous and subcutaneous mycosis mostly seen in tropical and subtropical areas and Fonsecaea pedrosoi is the most common cause. The authors describe the case of a diabetic Haitian woman, presenting with a chronic verrucous plaque without any history of trauma. Her histopathologic results showed epidermal hyperplasia and sclerotic bodies, which are diagnostic for CBM. Her therapy began with itraconazole 200 mg tablets twice a day. The unique feature of this patient is the coincidence of diabetes and CBM. However, to the best of our knowledge, this is the first documented case of human CBM in Miami, FL, which develops the awareness regarding this diagnosis among doctors in this area. There should be a close communication between dermatologists and pathologists to make an early diagnosis of CBM and also adequate therapy, which both are fundamental to improve patient's quality of life.

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.

A chitin-like component on sclerotic cells of Fonsecaea pedrosoi inhibits Dectin-1-mediated murine Th17 development by masking β-glucans

Fonsecaea pedrosoi (F. pedrosoi), a major agent of chromoblastomycosis, has been shown to be recognized primarily by C-type lectin receptors (CLRs) in a murine model of chromoblastomycosis. Specifically, the β-glucan receptor, Dectin-1, mediates Th17 development and consequent recruitment of neutrophils, and is evidenced to have the capacity to bind to saprophytic hyphae of F. pedrosoi in vitro. However, when embedded in tissue, most etiological agents of chromoblastomycosis including F. pedrosoi will transform into the sclerotic cells, which are linked to the greatest survival of melanized fungi in tissue. In this study, using immunocompetent and athymic (nu/nu) murine models infected subcutaneously or intraperitoneally with F. pedrosoi, we demonstrated that T lymphocytes play an active role in the resolution of localized footpad infection, and there existed a significantly decreased expression of Th17-defining transcription factor Rorγt and inefficient recruitment of neutrophils in chronically infected spleen where the inoculated mycelium of F. pedrosoi transformed into the sclerotic cells. We also found that Dectin-1-expressing histocytes and neutrophils participated in the enclosure of transformed sclerotic cells in the infectious foci. Furthermore, we induced the formation of sclerotic cells in vitro, and evidenced a significantly decreased binding capacity of human or murine-derived Dectin-1 to the induced sclerotic cells in comparison with the saprophytic mycelial forms. Our analysis of β-glucans-masking components revealed that it is a chitin-like component, but not the mannose moiety on the sclerotic cells, that interferes with the binding of β-glucans by human or murine Dectin-1. Notably, we demonstrated that although Dectin-1 contributed to the development of IL-17A-producing CD3+CD4+ murine splenocytes upon in vitro-stimulation by saprophytic F. pedrosoi, the masking effect of chitin components partly inhibited Dectin-1-mediated Th17 development upon in vitro-stimulation by induced sclerotic cells. Therefore, these findings extend our understanding of the chronicity of chromoblastomycosis.

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.

Pattern recognition receptors in antifungal immunity

Receptors of the innate immune system are the first line of defence against infection, being able to recognise and initiate an inflammatory response to invading microorganisms. The Toll-like (TLR), NOD-like (NLR), RIG-I-like (RLR) and C-type lectin-like receptors (CLR) are four receptor families that contribute to the recognition of a vast range of species, including fungi. Many of these pattern recognition receptors (PRRs) are able to initiate innate immunity and polarise adaptive responses upon the recognition of fungal cell wall components and other conserved molecular patterns, including fungal nucleic acids. These receptors induce effective mechanisms of fungal clearance in normal hosts, but medical interventions, immunosuppression or genetic predisposition can lead to susceptibility to fungal infections. In this review, we highlight the importance of PRRs in fungal infection, specifically CLRs, which are the major PRR involved. We will describe specific PRRs in detail, the importance of receptor collaboration in fungal recognition and clearance, and describe how genetic aberrations in PRRs can contribute to disease pathology.

Glycan analysis of Fonsecaea monophora from clinical and environmental origins reveals different structural profile and human antigenic response

Dematiaceous fungi constitute a large and heterogeneous group, characterized by having a dark pigment, the dihydroxynaftalen melanin—DHN, inside their cell walls. In nature they are found mainly as soil microbiota or decomposing organic matter, and are spread in tropical and subtropical regions. The fungus Fonsecaea monophora causes chromoblastomycosis in humans, and possesses essential mechanisms that may enhance pathogenicity, proliferation and dissemination inside the host. Glycoconjugates confer important properties to these pathogenic microorganisms. In this work, structural characterization of glycan structures present in two different strains of F. monophora MMHC82 and FE5p4, from clinical and environmental origins, respectively, was performed. Each one were grown on Minimal Medium (MM) and Czapeck-Dox (CD) medium, and the water soluble cell wall glycoconjugates and exopolysaccharides (EPS) were evaluated by NMR, methylation and principal component analysis (PCA). By combining the methylation and 2D NMR analyses, it was possible to visualize the glycosidic profiles of the complex carbohydrate mixtures. Significant differences were observed in β-D-Galf-(1→5) and (1→6) linkages, α- and β-D-Glcp-(1→3), (1→4), and (1→6) units, as well as in α-D-Manp. PCA from ¹H-NMR data showed that MMHC82 from CD medium showed a higher variation in the cell wall carbohydrates, mainly related to O-2 substituted β-D-Galf (δ 106.0/5.23 and δ 105.3/5.23) units. In order to investigate the antigenic response of the glycoconjugates, these were screened against serum from chromoblastomycosis patients. The antigen which contained the cell wall of MMHC82 grown in MM had β-D-Manp units that promoted higher antigenic response. The distribution of these fungal species in nature and the knowledge of how cell wall polysaccharides and glycoconjugates structure vary, may contribute to the better understanding and the elucidation of the pathology caused by this fungus.

Black Molds and Melanized Yeasts Pathogenic to Humans

A review is given of melanized fungi involved in human infection, including species forming budding cells and strictly filamentous representatives. Classically, they are known as "phaeoid" or "dematiaceous" fungi, and, today, agents are recognized to belong to seven orders of fungi, of which the Chaetothyriales and Pleosporales are the most important. Infections range from cutaneous or pulmonary colonization to systemic or disseminated invasion. Subcutaneous involvement, either primary or after dissemination, may lead to host tissue proliferation of dermis or epidermis. Particularly in the Chaetothyriales, subcutaneous and systemic infections may occur in otherwise apparently healthy individuals. Infections are mostly chronic and require extended antifungal therapy and/or surgery.

A case of nasal chromoblastomycosis causing epistaxis

BACKGROUND

Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissue that most commonly affects the feet and lower limbs. It is rare for this infection to occur on the face, and it is exceptionally rare for it to involve the nose and sinuses. This paper reports a rare case of nasal chromoblastomycosis in a 50-year-old Malaysian male.

CASE REPORT

The patient, who was a rubber plantation worker in the southern state of Johor, presented to the ENT clinic with a history of epistaxis. He did not recall any history of injury to the nose. Nasal endoscopy showed a pale yellowish lesion at the inferior edge of the left middle turbinate. Histology revealed that this was a case of chromoblastomycosis.

CONCLUSION

Chromoblastomycosis of the nasal cavity is very rare and can be mistaken for other granulomatous conditions in the nose. It progresses very slowly over many years. Our patient was managed conservatively, as he was not keen on undergoing surgical intervention. Lesion size remained the same at five months' follow up, with no recurrence of epistaxis.

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.

Chromoblastomycosis

Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissue. The infection usually results from a traumatic injury and inoculation of microorganism from a specific group of dematiaceous fungi (usually Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora carrionii). In the tissues fungi produce characteristic sclerotic cells or muriform cells. Dermal lesions can range from small nodules to large papillary-like eruptions. The disease has been described worldwide but the prevalence is higher in rural populations in countries with a tropical or subtropical climate, such as Madagascar in Africa and Brazil in South America. Diagnostic techniques are based on direct examination, culture and histopathology. Despite a variety of treatment modalities, which include long courses of antifungals, surgical excision and destructive physical therapies, the disease remains one of the most difficult deep mycotic infections to eradicate.

A case of extensive chromoblastomycosis from North India

A case of extensive chromoblastomycosis of the right leg and thigh with verruciform to nodular lesions evolving rapidly over five years duration is reported. The diagnosis was confirmed by visualizing pathognomonic pigmented muriform bodies with unique septate hyphae and mycological culture yielding Fonsecaea pedrosoi.

Case of chromoblastomycosis with pulmonary involvement

Chromoblastomycosis is a slowly growing chronic cutaneous mycosis associated with a variety of cutaneous lesions. Extra-dermal involvement is rare. A 58-year-old man was admitted to the hospital with nausea, vomiting, weakness and a history of weight loss. On inspection, he had a large verrucous mass in the sacral region, and two large subcutaneous nodules in the anterior thoracic wall. He claimed the lesions were several years old. Biopsy and histological studies were positive for chromoblastomycosis. Routine chest radiography showed hilar enlargement, and a chest computed tomography was ordered. Pulmonary nodules were evident, and endoscopically acquired samples were also positive for chromoblastomycosis. Extra-dermal and systemic involvement in chromoblastomycosis is exceedingly rare and often associated with immunosuppression. There is only one other case of pulmonary chromoblastomycosis reported in the published work.

Revisiting the clinical and histopathological aspects of patients with chromoblastomycosis from the Brazilian Amazon region

BACKGROUND AND AIMS

Chromoblastomycosis is a chronic fungal infection caused by species of the family Dematiaceae. Fonsecaea pedrosoi is the most common etiological agent. The objective of this study was to describe the epidemiological and mycological profile of patients with chromoblastomycosis from the Amazon region of Brazil and to correlate the clinical forms with the histopathological findings and severity criteria.

METHODS

Sixty-five patients were submitted to mycological (direct, culture, and microculture) and histopathological (hematoxylin-eosin staining) examination. Severity of the disease was classified according to the criteria proposed by Carrión in 1950.

RESULTS

Most patients were males (93.8%) and laborers (89.2%). There was a predominance of verrucous lesions (55.4%), which were mainly found on the lower limbs (81.5%). Two major types of tissue reaction were observed: a granulomatous reaction characterized by the formation of suppurative granulomas rich in fungal cells, which were almost always seen in verrucous lesions, and a reaction characterized by the formation of tuberculoid granulomas with few parasites, which were mainly found in well-delimited erythematous plaque-like and cicatricial lesions (p = 0.0001). A peculiar type of organized mycotic granuloma was observed in 20 subjects. Suppurative granulomas were more frequently detected in severe lesions (p = 0.0189) and in lesions with a duration of >10 years (p = 0.0408).

CONCLUSIONS

These results suggest that verrucous lesions present a less competent inflammatory tissue response than patients who develop a well-formed tuberculoid reaction. The latter is associated with a more effective immune response as observed in the limited clinical forms of chromoblastomycosis.

Generalized subcutaneous phaeohyphomycosis caused by Phialophora verrucosa: report of a case and review of literature

We report a case of subcutaneous phaeohyphomycosis due to Phialophora verrucosa in a 64-year-old Chinese farmer suffering from CD4+ lymphopenia. He presented with diffuse and infiltrated plaques involving the entire face including the eyes, neck, occiput, and extending to the dorsal regions of his torso. The patient is notable for the discrete multifocal nature of the illness in the absence of disseminated infection and rarity of P. verrucosa as a cause of subcutaneous phaeohyphomycosis.

Melanin in a meristematic mutant of Fonsecaea monophora inhibits the production of nitric oxide and Th1 cytokines of murine macrophages

Melanin is a complex polymer which is secreted outside or constitutes the structure of fungal cell wall. It is considered as an important virulence factor in opportunistic pathogenic fungi. In this study, one albino mutant (CBS 125149) was generated from a parent meristematic mutant (CBS 122845) of Fonsecaea monophora. Transmission electron microscopy profiles showed that melanin in the parent strains appeared as electron-dense granules which located on the cell wall surface. We extracted the cell wall fractions from the two different strains by an alkali-acid method. The different strains or its cell wall fractions were interacted with the activated RAW264.7. The pigmented strain and its cell wall fraction could reduce the expression of inducible nitric oxide synthase gene and inhibit the synthesis of nitric oxide in vitro (P < 0.05). Exacerbated Th2 and inhibited Th1 response occurred in the interaction between activated RAW264.7 and the pigmented strain or its cell wall fraction. Collectively, our results suggest that melanin plays an important role in escaping the killing of oxidative burst in vitro. The exacerbated Th2 response probably accelerates the persistence of the fungus.