Link ex Gray, 1821, de Hoog (1995)
Taxonomic classification
Kingdom: Fungi
Phylum: Ascomycota
Subphylum: Ascomycotina
Genus: Cladosporium
Description and Natural Habitats
Cladosporium is a dematiaceous (pigmented) mould widely distributed in air and rotten organic material and frequently isolated as a contaminant on foods. Some species are predominant in tropical and subtropical regions [533, 602]. Also, some Cladosporium spp. were isolated from fish and were associated with findings of infection [265].
Species
The genus Cladosporium includes over 30 species. The most common ones include Cladosporium elatum, Cladosporium herbarum, Cladosporium sphaerospermum, and Cladosporium cladosporioides.
Synonyms
See the summary of synonyms and teleomorph-anamorph relations for the Cladosporium spp. Among Cladosporium spp., Cladosporium herbarum has a teleomorph, Mycosphaerella tassiana.
Pathogenicity and Clinical Significance
Cladosporium spp. are causative agents of skin lesions, keratitis, onychomycosis, sinusitis and pulmonary infections [462, 1847, 2202].
Macroscopic Features
The growth rate of Cladosporium colonies is moderate on potato dextrose agar at 25°C and the texture is velvety to powdery. Similar to the other dematiaceous fungi, the color is olivaceous green to black from the front and black from the reverse. Most of the Cladosporium spp. do not grow at temperatures above 35°C [462, 602, 2202].
Microscopic Features
Cladosporium spp. produce septate brown hyphae, erect and pigmented conidiophores, and conidia.
While the conidiophores of Cladosporium cladosporioides and Cladosporium sphaerospermum are not geniculate, those of Cladosporium herbarum have a geniculate appearance. In addition, conidiophores of Cladosporium herbarum bear terminal and intercalary swellings. Conidia of Cladosporium spp. in general are elliptical to cylindrical in shape, pale to dark brown in color and have dark hila. They occur in branching chains that readily disarticulate. Conidial wall is smooth or occasionally echinulate. Cladosporium cladosporioides produces unicellular conidia. On the other hand, those of Cladosporium herbarum are two- to four-celled. Cladosporium sphaerospermum produces elongate and septate shield cells which are also known as ramoconidia [462, 2202].
Histopathologic Features
Brown (phaeoid) hyphae may be observed in infected tissue samples.
Compare to
Cladosporium differs from Cladophialophora by having conidia with dark brown colored hila (scars). While Cladophialophora bantiana can grow at 42-43°C, Cladophialophora carrionii and many species of Cladosporium do not grow at temperatures above 35°C.
The monoclonal antibody, EB-A2 used in the commercially available latex agglutination kit to detect galactomannan antigen in sera of patients with aspergillosis may cross react with Cladosporium herbarum [1153].
Laboratory Precautions
Cladosporium spp. should be handled with care in a biological safety cabinet.
Susceptibility
Very limited data are available on susceptibility profiles of Cladosporium spp.