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Category: Clinical Microbiology
Fusarium and Other Opportunistic Hyaline Fungi, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap118-1.gif /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap118-2.gifAbstract:
The opportunistic hyaline or lightly colored moulds constitute a phylogenetically diverse group of common to rare anamorphic and teleomorphic fungi that typically occur as saprobes in soil, in air, or on plant litter or as facultative plant pathogens. Some may be recovered from specimens without having any clinical significance. While several of the genera treated in this chapter include species having either lightly colored or dark (melanized) conidia, the emphasis is on those fungi that grow in tissue in the form of hyaline or lightly colored, septate hyphal elements. The term fusariosis is used to define infections caused by species of Fusarium, but the practice of coining disease names based on the genus of fungus involved is disadvantageous for infections caused by uncommon or rare fungal pathogens. In the chapter, the name of the teleomorph is used for species that are identified mainly by their sexual structures. Most of the pathogenic moulds considered in the chapter are classified in the form-class Hyphomycetes (genera which bear their conidia free). The conidiogenous cell produces a single conidium or multiple conidia. The number of hyaline fungal species that have been reported to cause opportunistic infection in humans and animals is increasing. The chapter also describes the salient colonial and microscopic features of the medically important species in the genus Fusarium and other selected currently recognized hyaline opportunists.
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(A) A member of the FSSC. Microconidia are borne from long monophialides. Macroconidia borne in the aerial mycelium are also present. (B) Fusarium oxysporum in the FOSC. Microconidia are borne from short monophialides. A few macroconidia are also present. (C) Chains of microconidia produced by Fusarium verticillioides (formerly Fusarium moniliforme) in the GFSC. (D) Fusarium proliferatum in the GFSC. Note polyphialides (arrows) with more than one opening not delimited by a septum. Truncate conidia that have been borne in chains as well as false heads are also present. (E) Macroconidia of Fusarium dimerum in the FDSC. Note that conidia are two celled and that the septum is in the middle. (F) Macroconidia of Fusarium delphinoides in the FDSC. Note that the septum in two-celled conidia is off-center, and three-celled conidia are also present. (G) Colony of Achaetomium strumarium showing yellowish surface mycelium and pink pigment on cornmeal agar after 5 weeks. (H) An isolate of Gymnascella hyalinospora described in reference 106 was glabrous and sterile when grown on potato dextrose agar for 15 days at 30°C.
(A) A member of the FSSC. Microconidia are borne from long monophialides. Macroconidia borne in the aerial mycelium are also present. (B) Fusarium oxysporum in the FOSC. Microconidia are borne from short monophialides. A few macroconidia are also present. (C) Chains of microconidia produced by Fusarium verticillioides (formerly Fusarium moniliforme) in the GFSC. (D) Fusarium proliferatum in the GFSC. Note polyphialides (arrows) with more than one opening not delimited by a septum. Truncate conidia that have been borne in chains as well as false heads are also present. (E) Macroconidia of Fusarium dimerum in the FDSC. Note that conidia are two celled and that the septum is in the middle. (F) Macroconidia of Fusarium delphinoides in the FDSC. Note that the septum in two-celled conidia is off-center, and three-celled conidia are also present. (G) Colony of Achaetomium strumarium showing yellowish surface mycelium and pink pigment on cornmeal agar after 5 weeks. (H) An isolate of Gymnascella hyalinospora described in reference 106 was glabrous and sterile when grown on potato dextrose agar for 15 days at 30°C.
(A) The same isolate of Gymnascella hyalinospora as in Fig. 1H turned yellow on oatmeal agar, with development of ascospores after 15 days at 30°C. (B) Ascospores of Gymnascella hyalinospora observed by scanning electron microscopy. Magnification, ×6,000. (C) Perithecium of a Microascus species. (D) Brown ascospores of Cephalotheca foveolata that formed after 8 weeks on carnation leaf agar at 25°C. (E) Phialemonium-like anamorph of Cephalotheca foveolata showing adelophialides (reduced phialides without a septum) and ellipsoidal conidia. (F) Tissue section stained with Gomori methenamine silver stain showing monokaryotic (clampless) hyphae of Schizophyllum commune in a pulmonary fungus ball. (G) Schizophyllum commune in slide culture preparation showing clamp connections and narrow pegs or spicules (arrows). Magnification, ×580. (H) Dikaryotic culture of Schizophyllum commune showing development of gilled fruiting bodies on potato dextrose agar after 7 weeks in the light.
(A) The same isolate of Gymnascella hyalinospora as in Fig. 1H turned yellow on oatmeal agar, with development of ascospores after 15 days at 30°C. (B) Ascospores of Gymnascella hyalinospora observed by scanning electron microscopy. Magnification, ×6,000. (C) Perithecium of a Microascus species. (D) Brown ascospores of Cephalotheca foveolata that formed after 8 weeks on carnation leaf agar at 25°C. (E) Phialemonium-like anamorph of Cephalotheca foveolata showing adelophialides (reduced phialides without a septum) and ellipsoidal conidia. (F) Tissue section stained with Gomori methenamine silver stain showing monokaryotic (clampless) hyphae of Schizophyllum commune in a pulmonary fungus ball. (G) Schizophyllum commune in slide culture preparation showing clamp connections and narrow pegs or spicules (arrows). Magnification, ×580. (H) Dikaryotic culture of Schizophyllum commune showing development of gilled fruiting bodies on potato dextrose agar after 7 weeks in the light.
(A) Setal hyphae of Inonotus tropicalis, slide culture preparation on potato flake agar, 10 days, 25°C. Bar, 20 μm. (B) Colony of Chrysosporium zonatum on potato dextrose agar after 14 days at 37°C. (C) Conidia of Chrysosporium zonatum formed on short curved stalks. (D) Rough stipe, metulae, and phialides of Geosmithia argillacea. Note also that conidia are initially cuneiform (wedge shaped). Bar, 10 μm. (E) Conidia of Myceliophthora thermophila in various stages of maturity. Mature conidia are dark and rough. Bar, 10 μm. (F) Culture of three different isolates of Onychocola canadensis after 5 weeks on Mycosel agar. (G) Setae ( appendages) of Onychocola canadensis. (H) Colony of Paecilomyces variotii on potato dextrose agar after 7 days.
(A) Setal hyphae of Inonotus tropicalis, slide culture preparation on potato flake agar, 10 days, 25°C. Bar, 20 μm. (B) Colony of Chrysosporium zonatum on potato dextrose agar after 14 days at 37°C. (C) Conidia of Chrysosporium zonatum formed on short curved stalks. (D) Rough stipe, metulae, and phialides of Geosmithia argillacea. Note also that conidia are initially cuneiform (wedge shaped). Bar, 10 μm. (E) Conidia of Myceliophthora thermophila in various stages of maturity. Mature conidia are dark and rough. Bar, 10 μm. (F) Culture of three different isolates of Onychocola canadensis after 5 weeks on Mycosel agar. (G) Setae ( appendages) of Onychocola canadensis. (H) Colony of Paecilomyces variotii on potato dextrose agar after 7 days.
(A) Colony of Paecilomyces lilacinus on potato dextrose agar after 14 days. (B) Verticillate conidiophores of Paecilomyces lilacinus bearing whorls of phialides. Bar, 10 μm. (C) Yellowish colony of Phialemonium curvatum on potato flake agar after 14 days at 25°C. (D) Colony of Phialosimplex caninus with yellow diffusible pigment on potato dextrose agar after 21 days at 30°C. (E) Conidia of Phialosimplex caninus borne in long chains or heads from simple basally inflated phialides. Bar, 2 μm. (F) Roughwalled conidia in chains formed on annellides in Scopulariopsis brevicaulis. Note branched conidiogenous apparatus. Magnification, ×580. (G) Colony of Trichoderma longibrachiatum on potato dextrose agar after 4 days at 37°C. Note that the plate has been inoculated on one side. (H) Green, oval conidia of Trichoderma longibrachiatum. Bar, 10 μm.
(A) Colony of Paecilomyces lilacinus on potato dextrose agar after 14 days. (B) Verticillate conidiophores of Paecilomyces lilacinus bearing whorls of phialides. Bar, 10 μm. (C) Yellowish colony of Phialemonium curvatum on potato flake agar after 14 days at 25°C. (D) Colony of Phialosimplex caninus with yellow diffusible pigment on potato dextrose agar after 21 days at 30°C. (E) Conidia of Phialosimplex caninus borne in long chains or heads from simple basally inflated phialides. Bar, 2 μm. (F) Roughwalled conidia in chains formed on annellides in Scopulariopsis brevicaulis. Note branched conidiogenous apparatus. Magnification, ×580. (G) Colony of Trichoderma longibrachiatum on potato dextrose agar after 4 days at 37°C. Note that the plate has been inoculated on one side. (H) Green, oval conidia of Trichoderma longibrachiatum. Bar, 10 μm.