Salient features of selected clinically significant dematiaceous fungia

Genus typeOrderGenus or speciesSalient phenotypic and/or diagnostic featuresb
Anamorphic (asexual) hyphomycete (conidia Capnodiales Hortaea werneckii Colonies olivaceous to black, mucoid to yeast-like, restricted; broad hyphae, wide annellated zones produce pale brown 1- to multicelled annelloconidia
    borne free) Cladosporium spp.Colonies olivaceous to black, velvety; conidiophores simple or branched, with or without nodes or swellings; ramoconidia (“shield cells”) give rise to branching chains of fragile, dark, mostly 1- or 2-celled conidia with prominent attachment scares (hila)
Dothideales Aureobasidium pullulans Colonies of A. pullulans var. pullulans mucoid, cream to pink initially and later brown to black, while those of A. pullulans var. melanigenum black at the outset; hyaline blastoconidia borne synchronously from hyaline hyphae; dark, thick-walled chlamydospores; DNA sequencing necessary for reliable differentiation of A. pullulans and H. dematioides
Hormonema dematioides Colonies similar to those seen in A. pullulans; hyaline blastoconidia produced asynchronously by percurrent proliferation from hyaline and dark hyphae
Pleosporales Alternaria spp.Colonies woolly, pale to olivaceous to black, with rapid growth; large, dark, euseptatec, muriform conidia in chains; A. infectoria conidia may be sparse and have long apical beaks serving as secondary conidiogenous cells
Bipolaris spp.Colonies woolly, gray to black, with rapid growth, bipolar germination, geniculate conidiophores, flattened hilum; B. spicifera has 3 distoseptad and 4 cells, while B. hawaiiensis has predominately 5 distosepta and 6 cells
Curvularia spp.Colonies woolly, gray to black, with rapid growth; geniculate conidiophores; conidia euseptate and curved (pronounced to subtle) due to swollen middle cell which is darker in C. lunata; C. lunata var. aeria produces large stroma visible with the naked eye
Exserohilum spp.Colonies woolly, gray to black, with rapid growth; geniculate conidiophores, truncate protruding hilum; E. rostratum has 7-9 distosepta; 8-10 cells; prominent dark basal and distal septa; E. longirostratum has longer conidia with central curvature; E. mcginnisii has subtle warty projections on conidia
Chaetothyriales Exophiala spp.Colonies mucoid initially, later more filamentous; conidiogenous cells predominately annellidic; phialides sometimes present; annellated black yeast synanamorph often present; many species very similar microscopically; nitrate positive; DNA sequencing of ITS region facilitates species identification; maximum temp varies; most frequently seen clinical species include E. xenobiotica, E. oligosperma, E. lecanii-corni, and E. phaeomuriformis
Exophiala dermatitidis Colonies black, mucoid; nitrate negative; growth at 40°C; black yeast E. exophialae synanamorph present; most common clinical Exophiala species; accurately identified by phenotypic features; obsolete name Wangiella dermatitidis
Cladophialophora spp.Colonies black, velvety; growth rates and temperatures vary for individual species; microscopically similar to Cladosporium spp. but lack conidiophores, “shield cells,” and prominent hila; conidia are nonfragile (remain intact in chains); neurotropic species include C. bantiana and C. modesta; other human pathogenic species include C. arxii, C. boppii, C. carrionii, C. devriesii, C. emmonsii, C. mycetomatis, C. samoënsis, andC. saturnica
Fonsecaea spp.Colonies olivaceous to black, velvety; conidia formed from swollen denticles giving rise to secondary and tertiary conidia in chains of up to four conidia; conidia also formed on sympodial conidiophores like in Rhinocladiella and occasionally from discrete phialides like in Phialophora; F. pedrosoi an agent of chromoblastomycosis, F. monophora an agent of both chromoblastomycosis and cerebral phaeohyphomycosis
Ochroconis gallopava Colonies are brownish, velvety, with a maroon diffusing pigment; 2-celled, clavate conidia borne from denticles; growth at 45°C; no growth on media containing cycloheximide; neurotropic; obsolete names Dactylaria gallopava, D. constricta var. gallopava
Phialophora spp.Colonies olivaceous to black, velvety; three species are clinically significant; P. verrucosa has dark, funnel-shaped collarettes; P. americana has deep, vase-shaped collarettes; the slow-growing P. europaea has very short collarettes
Rhinocladiella spp.Colonies olivaceous to black, velvety; long, erect, brown, unbranched sympodial conidiophores; 1-celled pale ellipsoidal conidia borne on crowded denticles; an Exophiala yeast synanamorph may be present; R. mackenziei is a neurotropic species in the genus with relatively few conidia per fertile part of the geniculate conidiophore; conidia 1-celled, pale brown, ellipsoidal with a prominent truncate hilum; poor growth at 25°C, good growth at 40°C; obsolete name Ramichloridium mackenziei; other pathogenic species include R. aquaspersa and R. similis
Veronaea botryosa Colonies gray to blackish-brown, woolly; long, brown conidiophores; pale brown, 2-celled conidia with a rounded apex and truncate base borne from closely spaced intercalary conidiogenous cells
Microascales Scedosporium spp.Colonies pale to yellowish-gray to darker gray, some with orange reverse, woolly; conidiogenous cells annellidic; some species produce a Pseudallescheria teleomorph and a Graphium synanamorph; similar human pathogenic species in the Pseudallescheria boydii species complex as defined by recent molecular studies include S. apiospermum, S. boydii, S. aurantiacum, and S. dehoogii; S. prolificans (obsolete name S. inflatum) possessing inflated annellidic conidiogenous cells, is unrelated to members of the P. boydii species complex
Scopulariopsis spp.Colonies gray to olivaceous-brown, woolly; conidiogenous cells annellidic; several very similar dark species are anamorphs of various Microascus spp.
Sordariales Madurella mycetomatis Colonies very slow growing and often heaped; dark brown to black; diffusible brown pigment; unlike M. grisea, M. mycetomatis grows at 40°C and fails to assimilate sucrose; precise identification facilitated by ITS sequencing
Myceliophthora thermophila Colonies light brown, powdery; ill-defined margin; conidia borne from ampulliform swellings are hyaline and smooth initially becoming rough and brown at maturity; growth at 48°C
Acrophialophora fusispora Colonies centrally dark front and reverse; unbranched, erect, brown, echinulate conidiophores are anchored by a foot cell; chains of conidia with fine or coarse spirals produced from apex of brown conidiophores and inflated phialides on hyaline hyphae; growth at 40°C
Calosphaeriales Phialemonium spp.Colonies buff to gray to yellow; conidiogenous cells phialides and adelophialides (reduced phialides lacking a basal septum); P. obovatum has obovate conidia and a green diffusing pigment; sporodochia-producing isolates of P. curvatum have been reported
Phaeoacremonium spp.Colonies range from buff to pale yellow to pale or dark pink to various shades of brown; hyphae brown; conidiophores often have small warts (exudates); three distinct types of phialides may be present (types I, II, and III); polyphialides may also be present; 1-celled conidia aggregate at apices of phialides and are commonly reniform (kidney shaped) to allantoid (sausage shaped); human pathogenic species that grow at 40°C include P. parasiticum (obsolete name Phialophora parasitica), P. rubrigenum, P. alvesii, P. amstelodamense, P. krajedenii, P. tardicrescens, and P. venezuelense
Pleurostomophora spp.Colonies of P. richardsiae (obsolete name Phialophora richardsiae) dark brown, velvety; phialides with prominent flaring collarettes bear globose, brown conidia while phialides with indistinct collarettes bear pale allantoid to cylindrical conidia; colonies of P. repens (obsolete name Phialophora repens) pale brown, phialides lack flaring collarettes, and conidia are pale, allantoid to cylindrical
Coniochaetales Lecythophora spp.Colonies moist, salmon to orange; conidiogenous cells primarily adelophialides; conidia aggregate at apices of conidiogenous cells; L. mutabilis distinguished from L. hoffmannii by dark chlamydoconidia
Ophiostomatales Sporothrix spp.Colonies initially cream-colored, moist, with a finely wrinkled surface, becoming brownish-grayish with the production of dark sessile conidia; hyaline, budding cigar-shaped yeast cells present in host and at 35°C; S. schenckii is a species complex as determined by calmodulin sequencing; human pathogenic species include S. schenckii (sessile conidia triangular to oval); S. globosa (sessile conidia globose, no growth at 37°C); S. brasiliensis (sessile conidia subglobose, geographically restricted to Brazil); S.luriei (dark sessile conidia absent)
Anamorphic (asexual) coelomycete (conidia borne within enclosed or semienclosed structures; organisms treated here have pycnidial conidiomata; frequently acquired by traumatic implantation) Pleosporales Phoma, Pleurophoma, Pleurophomopsis spp.Colonies pale to light brownish-gray to darker gray, woolly; pycnidia brown to black; conidia small (4-6 μm), oblong, sometimes slightly curved, hyaline, often guttulate (containing small droplets); species are very similar and best differentiated by ITS sequencing
Coniothyrium, Paraconiothyrium, Microsphaeropsis spp.Colonies pale gray to grayish-brown to brownish-black, some producing dark diffusible pigments into the agar, woolly; pycnidia brown to black; conidia mostly oblong of various sizes, pale brown to dark; species are very similar and best differentiated by ITS sequencing
Pyrenochaeta spp.Colonies olivaceous to gray-black, restricted, velvety; pycnidia brown to black with setae surrounding the ostiole; conidia 1-celled, hyaline
Botryosphaeriales Lasiodiplodia theobromae Colonies grayish-black, woolly; pycnidia ostiolate, sometimes with setae; conidiogenous cells annellidic; large conidia 20-30 by 10-15μm, initially aseptate and hyaline; 1 septate, dark, longitudinally striate at maturity; obsolete name Botryodiplodia theobromae
Neoscytalidium dimidiatum Colonies woolly, black, with rapid growth, filling plate within a few days; an otherwise similar hyaline variant is also referred to as N. dimidiatum; 1- and 2-celled, dark or hyaline arthroconidia not separated by disjunctor cells; thin hyaline and wide (10-12 μm) dark or hyaline hyphae; multilocular pycnidial coelomycetous synanamorph requires several weeks to mature on plant-based media and produces versicolored conidia (middle cell darker); no longer referred to as Nattrassia mangiferae as this organism is an unrelated fruit pathogen now known as Neofusicoccum mangiferae
Macrophomina phaseolina Colonies gray, woolly, with a dark diffusing pigment and small black dots representing immature/mature sclerotia; pycnidia and conidia usually not formed in culture; identification by sequencing
Sordariales Phomopsis spp.Colonies pale to light brown or gray, woolly; pycnidia brown to black, may be multilocular; conidia of two types, alpha conidia ellipsoidal while beta conidia long, filamentous, curved
Teleomorphic (sexual) (produce ascomata, asci, and ascospores in culture) Sordariales Chaetomium spp.Colonies olivaceous to grayish-brown, woolly; ascomata perithecial (opening at top) and covered with setae (hairs); large, reddish-brown elliptical ascospores; C. globosum, setae coiled, ascospores subglobose, growth at 35°C, no growth at 42°; C. atrobrunneum, neurotropic, setae mostly straight, ascospores narrowly fusoidal, growth at 42°C; C. perlucidum, neurotropic, very similar to C. atrobrunneum in colony morphology setae, and ascospore size; growth at 42°C
Achaetomium strumarium Colonies pale to light brown with reddish-brown diffusing pigment after 2 weeks, woolly; ascomata perithecial with long, slightly curved setae; ascospores hyaline to dark, 13-17.5 by 8.5-11 μm, fusoidal; neurotropic species with growth at 40°C
Pleosporales Leptosphaeria spp.Colonies dark, velvety to slightly woolly, slow-growing; ascomata cleistothecial (no opening); ascospores hyaline, mostly with 4-6 septa; L. senegalensis and L. thompkinsii distinguished by ascospore features
Microascales Microascus spp.Colonies initially white to gray to brownish; ascomata perithecial, developing as black dots in concentric rings on the agar, and may exude a cirrhus of red ascospores at maturity; species treated here have very similar, dark Scopulariopsis anamorphs; M. cinereus, short perithecial necks and orange-segment-shaped ascospores; M. cirrosus, longer perithecial necks with heart-shaped ascospores; M. trigonosporus, longer perithecial necks with triangular ascospores
Pseudallescheria spp.Colonies pale to yellowish gray to gray to brownish, woolly; ascomata cleistothecial; Scedosporium and Graphium anamorphs present; human pathogenic species as defined by recent molecular studies are Pseudallescheria boydii (anamorph Scedosporium boydii), Pseudallescheria apiosperma (anamorph Scedosporium apiospermum, heterothallic, does not form a teleomorph in culture, d-ribose negative), P. ellipsoidea
  • a Adapted from Table 14-1 from reference 724 with permission. This list is not all inclusive. Pictures of all organisms are available at or on the CD-ROM of the Atlas of Clinical Fungi, pilot version of 3rd ed. (174).

  • b On potato flake agar at 25°C.

  • c True septa continuous with outer wall.

  • d Pseudosepta where only inner walls are involved.