A case of chromomycosis with tumor-like growth

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.

Thermotherapy in dermatologic infections

The use of local induced hyperthermia or thermotherapy for dermatologic infections has not been fully explored in the more recent medical literature. Herein, we discuss the rationale behind the use of thermotherapy and review reported clinical experience with its use in the management of cutaneous infections.

Fungi growing on aromatic hydrocarbons: biotechnology's unexpected encounter with biohazard?

The biodegradation of aromatic hydrocarbons by fungi has traditionally been considered to be of a cometabolic nature. Recently, however, an increasing number of fungi isolated from air biofilters exposed to hydrocarbon-polluted gas streams have been shown to assimilate volatile aromatic hydrocarbons as the sole source of carbon and energy. The biosystematics, ecology, and metabolism of such fungi are reviewed here, based in part on re-evaluation of a collection of published hydrocarbon-degrading isolates obtained from authors around the world. Incorrect or outdated identifications in original publications are corrected by ribosomal DNA sequence analysis. The data show that many volatile-hydrocarbon-degrading strains are closely related to, or in some cases clearly conspecific with, the very restricted number of human-pathogenic fungal species causing severe mycoses, especially neurological infections, in immunocompetent individuals. Neurochemistry features a distinctive array of phenolic and aliphatic compounds that are related to molecules involved in the metabolism of aromatic hydrocarbons. Hence, there may be physiological connections between hydrocarbon assimilation and certain patterns of mammalian infection.

A monoclonal antibody to glucosylceramide inhibits the growth of Fonsecaea pedrosoi and enhances the antifungal action of mouse macrophages

Fungal glucosylceramides (GlcCer) are conserved lipid components in a large variety of pathogenic and non-pathogenic fungal species, but their biological functions are still unclear. Recent studies demonstrate that GlcCer are immunologically active components inducing the production of antifungal antibodies. In this work, a major GlcCer was purified and characterized from mycelial forms of Fonsecaea pedrosoi, the most frequent causative agent of chromoblastomycosis. As determined by fast atom bombardment mass spectrometry (FAB-MS) analysis, the purified molecule was identified as the conserved structure N-2'-hydroxyhexadecanoyl-1-beta-D-glucopyranosyl-9-methyl-4,8-sphingadienine. A monoclonal antibody (Mab) against this structure was used in indirect immunofluorescence with the different morphological stages of F. pedrosoi. Only the surface of young dividing cells was recognized by the antibody. Treatment of F. pedrosoi conidia with the Mab against GlcCer resulted in a clear reduction in fungal growth. In addition, the Mab also enhanced phagocytosis and killing of F. pedrosoi by murine cells. These results suggest that, in F. pedrosoi, GlcCer seem to be cell wall components targeted by antifungal antibodies that directly inhibit fungal development and also enhance macrophage function, supporting the use of monoclonal antibodies to GlcCer as potential tools in antifungal immunotherapy.

Phosphatase activity on the cell wall of Fonsecaea pedrosoi

The activity of a phosphatase was characterized in intact mycelial forms of Fonsecaea pedrosoi, a pathogenic fungus that causes chromoblastomycosis. At pH 5.5, this fungus hydrolyzed p-nitrophenylphosphate (p-NPP) to p-nitrophenol (p-NP) at a rate of 12.78 +/- 0.53 nmol p-NP per h per mg hyphal dry weight. The values of Vmax and apparent Km for p-NPP hydrolyses were measured as 17.89 +/- 0.92 nmol p-NP per h per mg hyphal dry weight and 1.57 +/- 0.26 mmol/l, respectively. This activity was inhibited at increased pH, a finding compatible with an acid phosphatase. The enzymatic activity was strongly inhibited by classical inhibitors of acid phosphatases such as sodium orthovanadate (Ki = 4.23 micromol/l), sodium molybdate (Ki = 7.53 micromol/l) and sodium fluoride (Ki = 126.78 micromol/l) in a dose-dependent manner. Levamizole (1 mmol/l) and sodium tartrate (10 mmol/l), had no effect on the enzyme activity. Cytochemical localization of the acid phosphatase showed electrondense cerium phosphate deposits on the cell wall, as visualized by transmission electron microscopy. Phosphatase activity in F. pedrosoi seems to be associated with parasitism, as sclerotic cells, which are the fungal forms mainly detected in chromoblastomycosis lesions, showed much higher activities than conidia and mycelia did. A strain of F. pedrosoi recently isolated from a human case of chromoblastomycosis also showed increased enzyme activity, suggesting that the expression of surface phosphatases may be stimulated by interaction with the host.

An unusual dematiaceous fungal infection of the skin caused by Fonsecaea pedrosoi: a case report and review of the literature

BACKGROUND

A case of an unusual dematiaceous fungal infection of the skin in a 43-year-old man with diabetes mellitus treated with steroids for reactive airway disease is presented. He developed chromoblastomycosis in the left wrist and was treated with antifungals and multiple surgical excisions.

RESULTS

Histologic examination of the excised tissue revealed widespread suppurative granulomatous inflammation in the dermis and subcutaneous tissue. Thick-walled internally septated brown fungal cells were found both inside multinucleated giant cells and extracellularly. Non-to-lightly pigmented septate hyphal elements, however, were also identified with special stains and, in retrospect, on one of the routinely stained sections. In culture, the organism was reported to initially grow as soft white colonies that soon turned to black and velvety.

CONCLUSIONS

The two unusual features of this case include the controversial report of the organism's initial growth in culture as soft white colonies and the presence of hyphal elements in addition to the sclerotic bodies in the dermis and subcutaneous tissue. This has not been reported before in human cases of dermal infection by Fonsecaea pedrosoi.

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.

[Therapy of infections caused by dematiaceous fungi]

Since dematiaceous fungi belong to the group of rare infectious agents causing mycoses, therapeutic recommendations are mainly deduced from observations of single cases. In cases of eumycetoma or focal phaeohyphomycoses of the central nervous system (e.g. caused by Cladophialophora bantiana or Exophiala dermatitidis) and in certain cases of chromoblastomycoses, the resection in toto is the therapy of choice, which may be accompanied by antimycotic medication. As antimycotic therapy ex juvantibus in case of phaeohy-phomycoses, a simultaneous application of itraconazole and 5-fluorocytosine is presently most promising. The success depends on an adequate duration of therapy.