Six years' experience in treatment of chromomycosis with 5-fluorocytosine,

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.

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

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

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

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

DNA-hsp65 vaccine as therapeutic strategy to treat experimental chromoblastomycosis caused by Fonsecaea pedrosoi

Chromoblastomycosis (CBM) is a chronic subcutaneous mycosis, caused by several dimorphic, pigmented dematiaceous fungi. Patients with the disease are still considered a therapeutic challenge, mainly due to its recalcitrant nature. There is no "gold standard" treatment for this neglected mycosis, but rather there are several treatment options. Chemotherapy alternatives include 5-flucytosine, itraconazole, terbinafine, fluconazole, thiabendazole, ketoconazole and amphotericin B, although the healing of severe cases is still uncommon. However, several studies have reported the DNA vaccine to be promising in the treatment for fungal infections; this vaccine allows the host to restore depressed cellular immunity, minimizing the toxic effects from conventional antifungal therapies. This work was therefore carried out aiming to establish a suitable model for experimental CBM, suggesting also new therapies, including DNA-hsp65 vaccine. By analyzing the morphometrical and histopathological aspects and by quantifying the fungal burden, the results showed the establishment of a chronic, although transitory, experimental CBM model with lesions similar to those presented in humans. A treatment regimen using intralesional itraconazole or amphotericin B was effective in treating experimental CBM, as was a therapy using naked DNA-hsp65 vaccine. It has also been shown that chemotherapy associated with DNA-hsp65 vaccine is promising in the treatment for CBM.

Managing chromoblastomycosis

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

Chromoblastomycosis

Chromoblastomycosis is a chronic subcutaneous mycotic infection caused by pigmented or dematiaceous saprophytic moulds ubiquitous in the environment. The most common etiologic agents are Fonsecaea pedrosoi and Cladophialophora carrionii, both of which can be isolated from plant debris. The infection usually follows traumatic inoculation through penetrating thorn or splinter wounds. The fungal agents develop as small clusters of cells known as muriform bodies. Several months after the injury, painless papules or nodules appear in the affected area progressing to scaly and verrucose plaques. Direct examinations of skin scrapings or histopathologic study demonstrates the typical muriform bodies. Microbiologic culture is necessary for the correct determination of the etiologic agent. Itraconazole is the treatment of choice, often in combination with surgery. Even so, results are often unsatisfactory as patients present late to medical services because of lack of funds and the fact that the disease usually affects the main family earner.

Subcutaneous mycoses

Subcutaneous mycoses include a heterogeneous group of fungal infections that develop at the site of transcutaneous trauma. Infection slowly evolves as the etiologic agent survives and adapts to the adverse host tissue environment. Diagnosis rests on clinical presentation, histopathology, and culture of the etiologic agents. This article considers sporotrichosis, chromoblastomycosis, and mycetoma.

Chromoblastomycosis: report of two cases from Nepal

Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissue caused by dematiaceous fungi. The first case, a 67-year-old male farmer, presented with itchy hyperkeratotic, scaly plaques with scarring and black dots on the lateral aspects of his left arm and dorsum of his left hand of 28 years duration. The case was clinically diagnosed as chromoblastomycosis. The second case, a 75-year-old farmer, presented with erythematous, crusted, scaly plaques on the dorsum of the left foot of 30 years duration. Initially, a clinical diagnosis of lupus vulgaris was made, but treatment with anti tuberculosis therapy showed no improvement. On the basis of histopathological examinations of skin biopsies and isolation of fungus on culture, both cases were diagnosed as chromoblastomycosis. To the best of our knowledge, these two cases are the first case reports of chromoblastomycosis from Nepal and are presented for their academic interest.

Successful treatment of chromomycosis using carbon dioxide laser associated with topical heat applications

A 59-year-old Japanese man presented with a slightly elevated, pruritic, erythematous plaque on his left buttock measuring 5 x 5 cm in diameter. The man had a history of chromomycosis, dating 6 years prior to the current consultation, for which he had been treated with oral terbinafine. Diagnosis of a recurrence of chromomycosis of the skin due to infection by Foncecaea pedrosoi was made after careful analysis of the clinical features, skin biopsy, KOH mounts, and fungal culture results. We administered topical heat therapy followed by treatment with CO2 laser to eradicate the unresponsive remnants of the lesion. The operative site re-epithelized within 10 weeks, and 1 year after the treatment there was no evidence of recurrence. For a recalcitrant case of chromomycosis, as in this case, the use of CO2 laser combined with topical heat therapy may be a new therapeutic modality.

Chromoblastomycosis: clinical and mycologic experience of 51 cases

This is a study of 51 cases of chromoblastomycosis detected in a 17-year period, all of which were clinically and mycologically proven by direct examinations, cultures and biopsies. The therapeutic results of the various treatments used are reported. Most cases were males (36 of 51; 70%), the mean age was 35 years and farmers predominated (74%); the most frequent lesions were in the lower limbs (54%). Major clinical presentations were nodular (41%) and verrucous (26%). The principal aetiologic agent isolated was Fonsecaea pedrosoi (90%). Overall results of the various treatments were as follows: 31% were cured, 57% improved and 12% failed. The best results were obtained with cryosurgery for small lesions, with itraconazole for large ones, and in some cases the combination of both treatments.

Agents for treatment of invasive fungal infections

The incidence of fungal infections continues to rise as the population of immunocompromised individuals increases. Despite the enlarging numbers of infections, there are only a few antifungal agents for treatment of deep-seated, invasive infections. These agents include amphotericin B, flucytosine, terbinafine, and several azoles. Progress has been made in understanding the role of these agents in a variety of infections and this article examines in detail these agents and their prophylactic, empiric, and therapeutic uses in invasive mycoses. This article focuses on general concepts of antifungal therapies and provides a detailed review of each antifungal agent available for treatment of deep-seated mycoses.

Antifungal agents. Part I. Amphotericin B preparations and flucytosine

Traditionally, amphotericin B has been the cornerstone of antifungal treatment. Toxicity, however, is a major dose-limiting factor of amphotericin B deoxycholate. Nevertheless, it continues to have a major role in the treatment of deep-seated mycotic infections. Recently, less nephrotic lipid formulations, including amphotericin B lipid complex, amphotericin B cholesteryl sulfate, and liposomal amphotericin B, have been introduced. The pharmacologic properties, main indications, recommended dosages, related costs, and adverse effects of these various preparations are summarized in this review. Orally administered flucytosine is useful in certain infections, particularly cryptococcal meningitis, but it should be used with caution in patients with renal insufficiency.

Phaeohyphomycosis of the paranasal sinuses masquerading as a neoplasm: a case report

A case of fungal infection of the paranasal sinuses simulating a neoplasm is reported. Fonsecaea pedrosoi, a dematiacious fungus, which has not been previously reported, was responsible for this unusual infection. Fungal infection may mimic malignant lesions of the paranasal sinuses; however, coexisting malignancy must be ruled out.

Itraconazole in the treatment of chromoblastomycosis due to Fonsecaea pedrosoi

The efficacy and tolerability of itraconazole in chromoblastomycosis due to Fonsecaea pedrosoi were evaluated in a non-comparative open clinical trial in 19 Brazilian patients with histopathologically and mycologically proven active chromoblastomycosis. Patients were classified in terms of severity and received itraconazole at the dosage of 200 to 400 mg per day until previously described criteria of cure have been reached. Clinical, mycologic, histopathologic, and laboratory evaluations were performed before, during, and after therapy. The plasma levels of itraconazole and the in vitro susceptibility of the isolates were determined in 15 cases. Clinical and biologic cure were achieved by eight patients (42%) having mild to moderate disease, after a mean duration of therapy of 7.2 months (3.2-29.6 months). Sterile scarred lesions were observed in a post-therapy follow-up lasting on average 9.6 months that was carried out in this subgroup. Clinical cure alone occurred after a mean period of 25.1 months of treatment (16-30.5 months) in seven patients (36%) with moderate to severe disease. Finally, clinical improvement was obtained in four patients (21%) with severe lesions after a mean treatment time of 17.6 months (10.7-22.5 months). All patients responded favorably to itraconazole therapy. No significant side effects nor biochemical alteration during this trial were important enough to interrupt the treatment. Our results support those of previous trials, suggesting that itraconazole is an effective compound against chromoblastomycosis due to Fonsecaea pedrosoi.

Cromoblastomicose produzida por Fonsecaea pedrosoi no Estado do Maranhão. I - aspectos clínicos, epidemiológicos e evolutivos

Com o objetivo de verificar o comportamento clínico-epidemiológico da cromoblastomicose no Estado do Maranhão, foi feito um estudo retrospectivo e prospectivo de 13 casos, no serviço de Doenças Infecciosas e Parasitárias do Hospital dos Servidores do Estado do Maranhão no período de nov/88 a julho/91. Para a investigação, foi utilizada uma ficha protocolo com todos os dados necessários para uma análise posterior. Nos casos analisados observou-se maior prevalência na faixa etária entre 50 e 60 anos (46,1%) e do sexo masculino (84,6%). Doze pacientes eram procedentes do Estado do Maranhão, dentre os quais 10 da microrregião da baixada ocidental maranhense. Quanto à profissão, 12 (92,3%) eram lavradores. Na sua maioria apresentavam as lesões nos membros inferiores deforma verrugo- confluentes, cor acastanhada, com prurido. O tempo de evolução variou de 0 a 15 anos em 12 casos (92,3%). Quanto aos aspectos laboratoriais, o exame histológico feito em 12 pacientes, diagnosticando cromoblastomicose em 100% deles e a cultura isolou Fonsecaea pedrosoi em 9 casos (70%). O tratamento realizado em todos os pacientes, com algumas variações foi feito com 5 - fluorocitosina apresentando bons resultados evolutivamente. Constatou-se neste trabalho uma provável zona endêmica de cromoblastomicose na microrregião da baixada ocidental maranhense, até agora desconhecida.

Treatment of chromoblastomycosis

Treatment of chromoblastomycosis is frequently difficult and unsatisfactory. A representative case is presented of this chronic subcutaneous fungal infection, characterized by warty, cauliflower-like lesions usually on the extremities. Chromoblastomycosis and its treatment are reviewed, with attention to itraconazole, a new triazole compound, as the possible drug of choice.

Treatment of chromomycosis by cryosurgery with liquid nitrogen: a report on eleven cases

Cryosurgery with liquid nitrogen was used to treat 11 cases of chromomycosis, 5 with localized lesions and 6 with generalized ones. Freezing time varied from 30 seconds to 4 minutes and the number of cycles from 1 to more than 40. All 5 cases with localized lesions responded extremely well to treatment, with no relapse for up to 53 months. Three patients with generalized lesions attained clinical and mycologic remission for up to 26 months, while 3 had significant improvement without cure. Cryosurgery with liquid nitrogen is therefore an effective treatment for chromomycosis, especially for cases presenting with localized lesions.

Treatment of chromoblastomycosis with itraconazole

The results of long-term itraconazole therapy in 10 patients with active chromoblastomycosis due to F. pedrosoi were reported. Therapy consisted of 100 or 200 mg/day of itraconazole, the length of therapy depending on the patient's response (12 to 24 months). This new triazole proved effective in reducing the number, size, and severity of the lesions in nine of the patients. Those patients with minor involvement profited more from therapy and were cured; patients with moderate involvement achieved either minor or major improvement. In most cases, signs and symptoms began to improve after 6 months of therapy. Mycological tests (in which tissue samples were treated with potassium hydroxide and cultured) became negative in six patients, but the fungus was eradicated in only three patients. Itraconazole produced no side effects. In spite of the need for long-term therapy, this new azole derivative effectively controls the disease.

In vitro sensitivity of environmental isolates of pathogenic dematiaceous fungi to azole compounds and a phenylpropyl-morpholine derivative

The in vitro sensitivity (minimum inhibitory concentrations; MICs) of 42 environmental isolates of pathogenic dematiaceous fungi to 7 azole compounds, viz. thiabendazole, ketoconazole, miconazole, econazole bifonazole, Bay n 7133, Bay 1 9139 and phenylpropyl-morpholine derivative, Ro14-4767/002 was studied by an agar dilution method using Emmon's Sabouraud dextrose agar (ESDA) as the culture medium. The isolates of Fonsecaea pedrosoi, Cladosporium carrionii, Exophiala jeanselmei and Ramichloridium subulatum were most sensitive to bifonazole with mean MICs of 0.06 microgram/ml or less; Phialophora verrucosa had an MIC of 0.05 microgram/ml to ketoconazole and Ro14-4767/002, respectively. Ochroconis sp had an MIC of 0.025 microgram/ml to Ro14-4767/002 and Cladosporium tennuisimum 0.39 microgram/ml to ketoconazole. Econazole and thiabendazole also showed good antifungal activity. The fungi were relatively resistant to the more recently developed azoles, viz. Bay n 7133 and Bay 1 9139, the later failing to inhibit C. tennuisimum at a concentration of 100 micrograms/ml. The minimum fungicidal concentrations (MFC) of the drugs were mostly within 2 to 8 fold of the MICs.

Treatment of chromomycosis with a CO2 laser

The successful employment of a carbon dioxide (CO2) laser in the eradication of localized chromomycosis is described. A review of alternative medical and surgical modalities used in treating this disorder is presented. The potential benefits of CO2 laser vs. cold steel surgery are discussed.

Mode of action of 5-fluorocytosine and 5-fluorouracil in dematiaceous fungi

The mode of action of 5-fluorocytosine (5FC) and 5-fluorouracil (5FU) in dematiaceous fungi was studied and compared with results of experiments in yeasts and Aspergillus species. In dematiaceous fungi 5FU is more potent than 5FC. The high activity of 5FU is related to a good and rapid uptake of this compound into the fungus cell. Both compounds exert fungistatic and fungicidal activity. A correlation exists between the amount of 5FU incorporated into RNA and its antifungal activity. The resistance frequency to 5FC varies from 2 x 10(-3) to 1 x 10(-7); resistance frequency to 5FU is generally lower. Addition of 5FC and 5FU to logarithmically multiplying cells inhibits increases of cell numbers and cell constituents after a delay period. The effects on the increase of protein and carbohydrate are more delayed than on the increase of DNA and RNA, indicating unbalanced growth. The concept of a dual biochemical mechanism, i.e. incorporation of 5FU into RNA and formation of 5-fluorodeoxy UMP leading to inhibition of DNA synthesis, previously proposed for the antifungal action of 5FC is also applicable to the action of 5FC and 5FU on the dematiaceous fungi.

Chromoblastomycosis and phaeohyphomycosis: new concepts, diagnosis, and mycology

The nomenclature for the mycoses caused by dematiaceous fungi should represent the combined clinical, pathologic, and mycologic relationships exhibited in the diseases. Chromoblastomycosis encompasses chronic, localized infections of the cutaneous and subcutaneous tissues that contain sclerotic bodies and histologically show hyperkeratotic pseudoepitheliomatous hyperplasia with keratolytic microabscess formation in the epidermis. In contrast, phaeohyphomycosis is a collective term for a heterogeneous group of mycotic infections that contain dematiaceous yeastlike cells, pseudohyphae-like elements, hyphae, or any combination of these forms in tissue. The terms superficial, cutaneous and corneal, subcutaneous, and systemic phaeohyphomycosis are proposed for the major categories of phaeohyphomycosis. The term chromomycosis is rejected for mycoses caused by the dematiaceous fungi.

Susceptibility of dermatiaceous fungi to amphotericin B, miconazole, ketoconazole, flucytosine and rifampin alone and in combination

The dematiaceous fungi comprise a group of organisms that are deeply pigmented and found in soil or on decaying organic material, such as wood. The majority of infections with these fungi presumably results from traumatic inoculation. Although various forms of infection have been appreciated for some time, none of the presently available antifungal drugs have been shown to have predictable activity against these organisms. We report on the activity in vitro of various antifungal agents alone and in combination against various dematiaceous fungi.

Chromomycosis. Successful treatment with 5-fluorocytosine

A case of chromomycosis, caused by Fonsecaea pedrosoi, was treated with 5-fluorocytosine. After 18 weeks of treatment the initial lesions had largely resolved, and no evidence of active disease was observed clinically, histologically or from fungal cultures of the biopsy material. Further resolution of the remaining hypertrophic scar was achieved by intralesional injections of triamcinolone acetonide. Minimal side-effects were encountered during the therapy, and no recurrence during an 18-month follow-up period was observed. The results of this study indicate that 5-fluorocytosine is an effective and relatively safe mode of therapy in chromomycosis.