Dematiaceous molds: Difference between revisions

Latest revision as of 21:11, 17 April 2022

Phenotypic grouping of fungi based on the presence of melanin

Background

Melanin is a virulence factor which protects again proteolytic enzymes, oxydation, and phagocytosis
Includes so-called "black yeast", which appear yeast-like early in culture
Colonies may grow slowly or quickly (e.g. within a week)
Pigment may take time to develop, but most will become olive, brown, or black

Microscopy

Genus identification is made based on a number of microscopic features
- Annelides are rings that appear following release of conidia at the apex
- Phialides are cylindrical or flask-shaped cells from which conidia are formed
- Geniculate pattern is a zig-zag caused by bending at the point of connection for each conidiophore
- Blastoconidia
- Arthroconidia
- Chlamydoconidia
- Large conidia
  - Single large muriform conifia suggests Epicoccum, Alternaria, and Ulocladium
  - Single large conidia with transverse septum, suggests Curvularia or Exserohilum
- Small conidia
  - Geniculate conidiophores suggests Fonsecaea
  - Conidia in chains suggests Cladosporium or Cladophialophora
  - Conidia on denticles (stems) suggests Madurella or Neoscytalidium
  - Conidia by phialides suggests Phaeoacremonium
- Unique reproductive bodies
  - Perithecia covered with hairs suggests Chaetomium
  - Pycnidia with ostioles (holes) suggests Phoma
Special tests, including thermal tolerance and germ tube test, can help to distinguish species within a genus
However, species identification is difficult without molecular assays

Clinical Manifestationss

Phaeohyphomycosis typically refers to cutaneous, subcutaneous, and disseminated disease, and is often acquired by traumatic innoculation
- Superficial cutaneous infection
- Subcutaneous phaeohyphomycosis
- Disseminated disease, more common in immunocompromised patients
Chromoblastomycosis
Mycetoma

Disease	Organisms	Notes
Localized cutaneous infection or abscess	Alternaria, Exophiala, Phialophora	Traumatic inoculation. Can become disseminated if immunocompromised.
Mycetoma	Madurella, Exophiala jeanselmei, Leptosphaeria	Spectrum from cutaneous to deep bone. Chronic draining, including granules.
Chromoblastomycosis	Cladophialophora carrionii, Fonsecaea, Phialophora	Chronic subcutaneous infection with sclerotic or muriform bodies
Keratitis		Most common in India. Usually from traumatic inoculation
Black piedra	Piedraia hortae	Present in the tropics. Involves only the hair.
Allergic sinusitis	Bipolaris, Curvularia, Exserohilum	More common in an atopic or asthmatic patient.
Allergic bronchopulmonary disease	Bipolaris, Curvularia	Rare.
Pulmonary disease	Scedosporium prolificans, Cladophialophora bantiana	Mostly in immunocompromised patients.
Cerebral disease	Cladophialophora bantiana, Verruonis gallopava, Exserohilum rostratum, Rhinocladiella, Exophiala dermatitidis	Occurs in immunocompetent people. Species involved varies geographically.
Disseminated disease	Curvularia, Exophiala, Bipolaris, Alternaria, Verruconis	Mostly in immunocompromised patients.

@@ Line 1: / Line 1: @@
-* Phenotypic grouping of fungi based on the presence of '''melanin'''
+*Phenotypic grouping of fungi based on the presence of '''melanin'''
-== Background ==
+==Background==
-* Melanin is a virulence factor which protects again proteolytic enzymes, oxydation, and phagocytosis
-* Includes so-called "black yeast", which appear yeast-like early in culture
-* Colonies may grow slowly or quickly (e.g. within a week)
-* Pigment may take time to develop, but most will become olive, brown, or black
+*Melanin is a virulence factor which protects again proteolytic enzymes, oxydation, and phagocytosis
-=== Microscopy ===
+*Includes so-called "black yeast", which appear yeast-like early in culture
-* Genus identification is made based on a number of microscopic features
+*Colonies may grow slowly or quickly (e.g. within a week)
-** '''Annelides''' are rings that appear following release of conidia at the apex
+*Pigment may take time to develop, but most will become olive, brown, or black
-** '''Phialides''' are cylindrical or flask-shaped cells from which conidia are formed
-** '''Geniculate pattern''' is a zig-zag caused by bending at the point of connection for each conidiophore
-** '''Blastoconidia'''
-** '''Arthroconidia'''
-** '''Chlamydoconidia'''
-** '''Large conidia'''
-*** Single large muriform conifia suggests [[Epicoccum speices]], [[Alternaria species]], and [[Ulocladium species]]
-*** Single large conidia with transverse septum, suggests [[Curvularia species]] or [[Exserohilum species]]
-** '''Small conidia'''
-*** Geniculate conidiophores suggests [[Fonsecaea species]]
-*** Conidia in chains suggests [[Cladosporium species]] or [[Cladophialophora species]]
-*** Conidia on '''denticles''' (stems) suggests [[Madurella species]] or [[Neoscytalidium species]]
-*** Conidia by phialides suggests [[Phaeoacremonium]]
-** Unique reproductive bodies
-*** '''Perithecia''' covered with hairs suggests [[Chaetomium species]]
-*** '''Pycnidia''' with '''ostioles''' (holes) suggests [[Phoma species]]
-* Special tests, including thermal tolerance and germ tube test, can help to distinguish species within a genus
-* However, species identification is difficult without molecular assays
+===Microscopy===
-== Clinical Presentations ==
-* Phaeohyphomycosis typically refers to cutaneous, subcutaneous, and disseminated disease, and is often acquired by traumatic innoculation
+*Genus identification is made based on a number of microscopic features
-** Superficial cutaneous infection
+**'''Annelides''' are rings that appear following release of conidia at the apex
-** Subcutaneous phaeohyphomycosis
+**'''Phialides''' are cylindrical or flask-shaped cells from which conidia are formed
-** Disseminated disease, more common in immunocompromised patients
+**'''Geniculate pattern''' is a zig-zag caused by bending at the point of connection for each conidiophore
-* [[Chromoblastomycosis]]
+**'''Blastoconidia'''
-* [[Mycetoma]]
+**'''Arthroconidia'''
+**'''Chlamydoconidia'''
+**'''Large conidia'''
+***Single large muriform conifia suggests [[Epicoccum]], [[Alternaria]], and [[Ulocladium]]
+***Single large conidia with transverse septum, suggests [[Curvularia]] or [[Exserohilum]]
+**'''Small conidia'''
+***Geniculate conidiophores suggests [[Fonsecaea]]
+***Conidia in chains suggests [[Cladosporium]] or [[Cladophialophora]]
+***Conidia on '''denticles''' (stems) suggests [[Madurella]] or [[Neoscytalidium]]
+***Conidia by phialides suggests [[Phaeoacremonium]]
+**Unique reproductive bodies
+***'''Perithecia''' covered with hairs suggests [[Chaetomium]]
+***'''Pycnidia''' with '''ostioles''' (holes) suggests [[Phoma]]
+*Special tests, including thermal tolerance and [[germ tube test]], can help to distinguish species within a genus
+*However, species identification is difficult without molecular assays
+==Clinical Manifestationss==
+*Phaeohyphomycosis typically refers to cutaneous, subcutaneous, and disseminated disease, and is often acquired by traumatic innoculation
+**Superficial cutaneous infection
+**Subcutaneous phaeohyphomycosis
+**Disseminated disease, more common in immunocompromised patients
+*[[Chromoblastomycosis]]
+*[[Mycetoma]]
 {| class="wikitable"
-! Disease !! Organisms !! Notes
+!Disease!!Organisms!!Notes
 |-
-| Localized cutaneous infection or abscess
+|Localized cutaneous infection or abscess
-| [[Alternaria species]], [[Exophiala species]], [[Phialophora species]]
+|[[Alternaria]], [[Exophiala]], [[Phialophora]]
-| Traumatic inoculation. Can become disseminated if immunocompromised.
+|Traumatic inoculation. Can become disseminated if immunocompromised.
 |-
-| [[Mycetoma]]
+|[[Mycetoma]]
-| [[Madurella species]], [[Exophiala jeanselmei]], [[Leptosphaeria species]]
+|[[Madurella]], [[Exophiala jeanselmei]], [[Leptosphaeria]]
-| Spectrum from cutaneous to deep bone. Chronic draining, including granules.
+|Spectrum from cutaneous to deep bone. Chronic draining, including granules.
 |-
-| [[Chromoblastomycosis]]
+|[[Chromoblastomycosis]]
-| [[Cladophialophora carrionii]], [[Fonsecaea species]], [[Phialophora species]]
+|[[Cladophialophora carrionii]], [[Fonsecaea]], [[Phialophora]]
-| Chronic subcutaneous infection with sclerotic or muriform bodies
+|Chronic subcutaneous infection with sclerotic or muriform bodies
 |-
-| Keratitis
+|Keratitis
 |
-| Most common in India. Usually from traumatic inoculation
+|Most common in India. Usually from traumatic inoculation
 |-
-| [[Piedraia hortae|Black piedra]]
+|[[Piedraia hortae|Black piedra]]
-| [[Piedraia hortae]]
+|[[Piedraia hortae]]
-| Present in the tropics. Involves only the hair.
+|Present in the tropics. Involves only the hair.
 |-
-| Allergic sinusitis
+|Allergic sinusitis
-| [[Bipolaris species]], [[Curvularia species]], [[Exserohilum species]]
+|[[Bipolaris]], [[Curvularia]], [[Exserohilum]]
-| More common in an atopic or asthmatic patient.
+|More common in an atopic or asthmatic patient.
 |-
-| Allergic bronchopulmonary disease
+|Allergic bronchopulmonary disease
-| [[Bipolaris species]], [[Curvularia species]]
+|[[Bipolaris]], [[Curvularia]]
-| Rare.
+|Rare.
 |-
-| Pulmonary disease
+|Pulmonary disease
-| [[Scedosporium prolificans]], [[Cladophialophora bantiana]]
+|[[Scedosporium prolificans]], [[Cladophialophora bantiana]]
-| Mostly in immunocompromised patients.
+|Mostly in immunocompromised patients.
 |-
-| Cerebral disease
+|Cerebral disease
-| [[Cladophialophora bantiana]], [[Verruonis gallopava]], [[Exserohilum rostratum]], [[Rhinocladiella species]], [[Exophiala dermatitidis]]
+|[[Cladophialophora bantiana]], [[Verruonis gallopava]], [[Exserohilum rostratum]], [[Rhinocladiella]], [[Exophiala dermatitidis]]
-| Occurs in immunocompetent people. Species involved varies geographically.
+|Occurs in immunocompetent people. Species involved varies geographically.
 |-
-| Disseminated disease
+|Disseminated disease
-| [[Curvularia species]], [[Exophiala species]], [[Bipolaris species]], [[Alternaria species]], [[Verruconis species]]
+|[[Curvularia]], [[Exophiala]], [[Bipolaris]], [[Alternaria]], [[Verruconis]]
-| Mostly in immunocompromised patients.
+|Mostly in immunocompromised patients.
 |}
+==Further Reading==
-[[Category:Fungi]]
+*ESCMID and ECMM joint clinical guidelines for the diagnosis and management of systemic phaeohyphomycosis: diseases caused by black fungi. ''Clin Micro Infection''. 2014 20(Suppl. 3):47-75. doi: [https://doi.org/10.1111/1469-0691.12515 10.1111/1469-0691.12515]
+[[Category:Filamentous fungi]]