Difference between revisions of "Yeast-like fungi"

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#REDIRECT[[:Category:Yeast-like Fungi]]
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|linkpage =Fungi
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|linktext =FUNGI
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|pagetype=Bugs
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<br>
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==Candidosis==
 +
[[Image:Sour Crop.jpg|thumb|right|200px|Sour Crop - Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath]]
 +
*''Candidia albicans'' is the most important species
 +
**''C. tropicalis'' and ''C. pelliculosa'' are other important species
 +
 
 +
*World wide distribution
 +
 
 +
*Usually an endogenous mycoses
 +
 
 +
*Noramlly present on [[Skin - Anatomy & Physiology|skin]], [[Female Reproductive Tract -The Vagina/Vestibule - Anatomy & Physiology|vagina]] and in the [[Alimentary - Anatomy & Physiology|GI tract]]
 +
 
 +
*Immunocompromised animals may show symptoms
 +
 
 +
*Usually lesions on mucous membranes and at mucocutaneous junctions
 +
 
 +
*Many species have been implicated in bovine [[Mastitis|mastitis]]
 +
 
 +
*''C. albicans'' has been isolated in porcine stomach ulcers
 +
 
 +
*''C. rugosa'' has been implicated in pyometra in mares
 +
 
 +
*Infection of the [[Crop- Anatomy and Physiology|crop]], [[Crop- Anatomy and Physiology|oesophagus]] and [[The Avian Oral Cavity - Anatomy & Physiology|mouth]] occur in poultry and other birds leading to '''sour crop'''
 +
**White-grey lesions in mouth which adhere loosly to the mucous membrane
 +
**[[Crop- Anatomy and Physiology|Crop]] wall may be thickened
 +
**[[Crop- Anatomy and Physiology|Crop]] wall may be covered by a yellow-white necrotic material
 +
**Underlying tissue is inflammed
 +
 
 +
*Causes thrush in humans
 +
 
 +
*''C. albicans'' causes metritis and vaginitis in mares and genital candidiosis in stallions (and bulls)
 +
 
 +
*Skin scrapings in 20% KOH for microscopy
 +
 
 +
*Diphtheritic membranes, pus and fluids can be examined by Lactophenol Cotton Blue and stained by Gram or Methylene Blue stain
 +
 
 +
*Gram positive, oval, thin-walled budding cells with hyphal fragments
 +
 
 +
*Grow on Blood agar and Sabouraud's Dextrose agar producing soft, creamy colonies in 24-48 hours
 +
 
 +
*Grossly:
 +
**Exudative, papular, pustular to ulcerative dermatitis
 +
**Stomatitis and otitis externa may develop
 +
 
 +
*Microscopically:
 +
**Spongiotic neutrophilic pustular inflammation
 +
**Parakeratosis
 +
**Ulcerations
 +
**Superficial exudate containing organisms
 +
 
 +
*''Candida'' spp. in [[Mycotic skin infections - Pathology#Candidiasis|candidiasis]]
 +
 
 +
==Cryptococcosis==
 +
 
 +
*Over 19 species
 +
**''C. neoformans'' only major pathogen
 +
 
 +
*Worldwide
 +
 
 +
*Occurs in high concentrations in pigeon droppings (high creatinine concentration)
 +
**The pigeon is not infected
 +
**''C. neoformis'' colonise the droppings after they have been excreted
 +
**Also found in fruit, milk and soil
 +
 
 +
*Exogenous, inhaled infection which is generally sporadic (non-contageous)
 +
**Can also be absorbed via skin penetration and ingestion
 +
 
 +
*May be a primary pathogen or opportunistic
 +
 
 +
*Targets the [[Cardiorespiratory System - Anatomy & Physiology|respiratory system]]
 +
**Including the [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]]
 +
**Also can be systemic, cutaneous, visceral, skeletal or ocular
 +
 
 +
*Causes sporadic mastitis in cattle
 +
**Can spread within the herd
 +
 
 +
*Affects the [[Nervous System - CNS - Anatomy & Physiology|CNS]] of dogs and cats
 +
**[[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]] and [[Pharynx - Anatomy & Physiology|pharynx]] can be infected with dissemination to the [[Nervous System - CNS - Anatomy & Physiology|CNS]] and other tissues
 +
***E.g. [[Lungs - Anatomy & Physiology|Lungs]], [[Urinary System - Anatomy & Physiology#The Kidney|kidneys]] and [[Joints - Anatomy & Physiology|joints]]
 +
**Also causes subcutaneous granulomas
 +
**The tip of the nose is a common site of infection in cats
 +
***See [[Respiratory Fungal Infections - Pathology#In Cats|here]]
 +
 
 +
*Causes myxoma-like lesions of the [[Lungs - Anatomy & Physiology|lung]] and [[Lips - Anatomy & Physiology|lip]] in horses
 +
 
 +
*Causes cryptococcal meningitis in humans
 +
 
 +
*Also affects dolphins, foxes, ferrets, monkeys, birds, cheetahs and guinea-pigs
 +
 
 +
*Large yeast with capsule seen using India ink stain
 +
 
 +
*Stains with PAS (Periodic acis Schiff)
 +
 
 +
*Gram positive
 +
 
 +
*Grows on blood agar and Sabouraud's Dextrose agar forming white, granular colonies which become slimy, mucoid and turn creamy/brown within a week
 +
 
 +
*Species identified by carbohydrate assimilation tests
 +
 
 +
*Antigen and antibody should be tested for as [[Immunoglobulins - WikiBlood|antibody]] formed by the body is soon overwhelmed and neutralised by abundent polysaccharide antigen from the capsule in active, systemic infections
 +
**Latex agglutination for [[Adaptive Immune System - WikiBlood#Actions of the Adaptive Immune System|antigen]], complement fixation, ELISA and IFAT can be used
 +
 
 +
==Geotrichosis==
 +
 
 +
*''G. candidum''
 +
 
 +
*Rare
 +
 
 +
*Two forms: the yeast-like (glaborous) and fluffy
 +
 
 +
*Affects a wide range of species
 +
 
 +
*Usually diagnosed post-mortem
 +
 
 +
*Affects the mucous membranes, udder, [[Bronchi and bronchioles - Anatomy & Physiology|bronchi]] and [[Lungs - Anatomy & Physiology|lungs]]
 +
 
 +
*Usually mild, causing suppurative granulomas
 +
 
 +
*Can be recovered from otitis externa infections in dogs
 +
 
 +
*Organisms appear as rectangular or spherical arthrospores on wet mounts
 +
**Thick walled, non-budding, gram positive
 +
 
 +
*Grow on Sabouraud's Dextrose agar
 +
**Membranous colonies
 +
**Do not grow well on blood agar
 +
 
 +
==''Malassezia pachydermidis''==
 +
[[Image:Malassezia pachydermidis.jpg|thumb|right|150px|''Malassezia pachydermidis'' - Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath]]
 +
*Normally present in oily areas on the external [[The Ear - Anatomy & Physiology|ear]] canal and [[Skin - Anatomy & Physiology|skin]] in dogs
 +
**Some strains have been recovered from the [[The Ear - Anatomy & Physiology|ear]] canal of cats
 +
 
 +
*Bottle-shaped, small budding cells, non-mycelial
 +
 
 +
*Gram stain shows purple yeast cells with a very wide base
 +
 
 +
*Grows on Sabouraud's Dextrose agar in 2 weeks of incubation at room temperature
 +
 
 +
*Greenish discolouration on blood agar
 +
 
 +
*Clinical disease may cause yeast to proliferate and cause infection
 +
 
 +
*Grossly:
 +
**Regional lesions: muzzle, [[The Ear - Anatomy & Physiology|ears]], interdigital, perianal
 +
**Or generalised disease
 +
**Erythematous, hyperpigmented, [[Skin Glossary - Pathology|lichenified]] and scaly lesions with alopecia
 +
 
 +
*Microscopically:
 +
**[[Skin Glossary - Pathology|hyperkeratosis, parakeratosis]]
 +
**Spongiotic pustular dermatitis
 +
**[[Skin Glossary - Pathology|Acanthosis]]
 +
**Organisms are usually present- minimum 3-5 yeasts per high-power field must be found to imply cause of disease
 +
 
 +
*''Malassezia pachydermis'' in [[Mycotic skin infections - Pathology#Malassezia dermatitis|malassezia dermatitis]]
 +
 
 +
==''Rhodotorula''==
 +
 
 +
*''Rhodotorula minuta'' and ''R. rubra''
 +
 
 +
*Canine [[The Ear - Anatomy & Physiology|ear]] infections
 +
 
 +
*Equine [[Female Reproductive Tract -The Uterus - Anatomy & Physiology|uterus]]
 +
 
 +
*Seldom seen in animal infections
 +
 
 +
==''Torulopsis glabrata''==
 +
 
 +
*Commensal in animals and is found in the soil
 +
 
 +
*Implicated in cases of:
 +
**Pyelonephritis, pneumonia, septicaemia and meningitis (humans)
 +
**Mastitis and abortion in cattle
 +
**Systemic infection of monkeys and dogs
 +
 
 +
==Trichosporonosis==
 +
 
 +
*Found in soil
 +
 
 +
*Deuteromycetes yeast
 +
 
 +
*''Trichosporonosis beigelii''
 +
**Implicated in feline nasal granuloma, [[Mycotic skin infections - Pathology#Superficial mycoses|skin infections]] in horses and monkeys, mastitis in cattle and sheep and in feline bladder infections
 +
 
 +
*''T. capitum'' implicated in bovine mastitis
 +
 
 +
==Further Links==
 +
 
 +
*[[Mycotic skin infections - Pathology]]
 +
 
 +
*[[Antifungal Drugs]]

Revision as of 20:24, 28 April 2009



Infectious agents and parasitesWikiBugs Banner.png
FUNGI



Candidosis

Sour Crop - Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath
  • Candidia albicans is the most important species
    • C. tropicalis and C. pelliculosa are other important species
  • World wide distribution
  • Usually an endogenous mycoses
  • Immunocompromised animals may show symptoms
  • Usually lesions on mucous membranes and at mucocutaneous junctions
  • Many species have been implicated in bovine mastitis
  • C. albicans has been isolated in porcine stomach ulcers
  • C. rugosa has been implicated in pyometra in mares
  • Infection of the crop, oesophagus and mouth occur in poultry and other birds leading to sour crop
    • White-grey lesions in mouth which adhere loosly to the mucous membrane
    • Crop wall may be thickened
    • Crop wall may be covered by a yellow-white necrotic material
    • Underlying tissue is inflammed
  • Causes thrush in humans
  • C. albicans causes metritis and vaginitis in mares and genital candidiosis in stallions (and bulls)
  • Skin scrapings in 20% KOH for microscopy
  • Diphtheritic membranes, pus and fluids can be examined by Lactophenol Cotton Blue and stained by Gram or Methylene Blue stain
  • Gram positive, oval, thin-walled budding cells with hyphal fragments
  • Grow on Blood agar and Sabouraud's Dextrose agar producing soft, creamy colonies in 24-48 hours
  • Grossly:
    • Exudative, papular, pustular to ulcerative dermatitis
    • Stomatitis and otitis externa may develop
  • Microscopically:
    • Spongiotic neutrophilic pustular inflammation
    • Parakeratosis
    • Ulcerations
    • Superficial exudate containing organisms

Cryptococcosis

  • Over 19 species
    • C. neoformans only major pathogen
  • Worldwide
  • Occurs in high concentrations in pigeon droppings (high creatinine concentration)
    • The pigeon is not infected
    • C. neoformis colonise the droppings after they have been excreted
    • Also found in fruit, milk and soil
  • Exogenous, inhaled infection which is generally sporadic (non-contageous)
    • Can also be absorbed via skin penetration and ingestion
  • May be a primary pathogen or opportunistic
  • Causes sporadic mastitis in cattle
    • Can spread within the herd
  • Affects the CNS of dogs and cats
  • Causes myxoma-like lesions of the lung and lip in horses
  • Causes cryptococcal meningitis in humans
  • Also affects dolphins, foxes, ferrets, monkeys, birds, cheetahs and guinea-pigs
  • Large yeast with capsule seen using India ink stain
  • Stains with PAS (Periodic acis Schiff)
  • Gram positive
  • Grows on blood agar and Sabouraud's Dextrose agar forming white, granular colonies which become slimy, mucoid and turn creamy/brown within a week
  • Species identified by carbohydrate assimilation tests
  • Antigen and antibody should be tested for as antibody formed by the body is soon overwhelmed and neutralised by abundent polysaccharide antigen from the capsule in active, systemic infections
    • Latex agglutination for antigen, complement fixation, ELISA and IFAT can be used

Geotrichosis

  • G. candidum
  • Rare
  • Two forms: the yeast-like (glaborous) and fluffy
  • Affects a wide range of species
  • Usually diagnosed post-mortem
  • Usually mild, causing suppurative granulomas
  • Can be recovered from otitis externa infections in dogs
  • Organisms appear as rectangular or spherical arthrospores on wet mounts
    • Thick walled, non-budding, gram positive
  • Grow on Sabouraud's Dextrose agar
    • Membranous colonies
    • Do not grow well on blood agar

Malassezia pachydermidis

Malassezia pachydermidis - Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath
  • Normally present in oily areas on the external ear canal and skin in dogs
    • Some strains have been recovered from the ear canal of cats
  • Bottle-shaped, small budding cells, non-mycelial
  • Gram stain shows purple yeast cells with a very wide base
  • Grows on Sabouraud's Dextrose agar in 2 weeks of incubation at room temperature
  • Greenish discolouration on blood agar
  • Clinical disease may cause yeast to proliferate and cause infection
  • Grossly:
    • Regional lesions: muzzle, ears, interdigital, perianal
    • Or generalised disease
    • Erythematous, hyperpigmented, lichenified and scaly lesions with alopecia
  • Microscopically:

Rhodotorula

  • Rhodotorula minuta and R. rubra
  • Canine ear infections
  • Seldom seen in animal infections

Torulopsis glabrata

  • Commensal in animals and is found in the soil
  • Implicated in cases of:
    • Pyelonephritis, pneumonia, septicaemia and meningitis (humans)
    • Mastitis and abortion in cattle
    • Systemic infection of monkeys and dogs

Trichosporonosis

  • Found in soil
  • Deuteromycetes yeast
  • Trichosporonosis beigelii
    • Implicated in feline nasal granuloma, skin infections in horses and monkeys, mastitis in cattle and sheep and in feline bladder infections
  • T. capitum implicated in bovine mastitis

Further Links