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Tubular branching structure
Mass of intertwining hyphae
Cross wall with central pore to produce continuous mass of cytoplasm (coenocytic)
Tubular branching structure
Mycelium (2 types)
- Mass of entertwining hyphae
- 1) Vegetative: Grow into/ penetrate medium
- 2) Aerial: Project above the sruface of the medium
Cross wall with central pore to produce continuous mass of cytoplasm (coenocytic)
2 Cell membrane components of fungi
3 Cell wall components of fungi
- Chitin (N-acetylglucosamine in B-1,4 glycosidic bonds)
- Glucan (B-1,6 D-glucose)
- Mannan (a-1,6 D-mannose)
Anamorphs produce by
Organisms that produce by asexual reproduction are also known as
Anamorphs are imperfect fungi that reproduce by 3 mechanisms.
- 1) Sporulation (and subsequently germination)
- 2) Blastospore formation (budding)
- 3) Fragmentation of hyphae
5 Types of asexual spores
- (The asexual with CHLAMYDia took the CAB SPORting event.)
Asexual single spores developing at tip of specialized hyphae.
Conidia, hyphae are known as conidiophores
Asexual spores that develop within the hyphae and released by fragmentation of hyphae.
Asexual buds that develop from yeast-like cells.
1) Develop single spores at tip of specialized hyphae
2) Develop within hyphae --> fragmentation
3) Develop from yeast-like cells
4) Develop from intercalated hyphal cells
5) Sac-like structures that develop at end of specialized hyphae
- 1) Conidia
- 2) Arthrospores
- 3) Blastospores
- 4) Chlamydospores
- 5) Sporangiospores
Asexual thick walled spores that develop from terminal or intercalated hyphal cells (resistant to drying, heat)
Asexual sac-like structures (______) that develop at the end of specialized hyphae (_______).
Sporangiospores (sporangia, sporangiospores)
Organisms that reproduce via sexual reproduction are known as _______ or _______
Cells from a single colony that can engage in sexual reproduction
Two different colonies of opposite mating types that can reproduce via sexual reproduction.
2 Types of fungi species that reproduce sexually
- Homothallic: cells from a single colony
- Heterothallic: 2 different colonies of opposite mating types
Name 3 areas of the body from which fungi can be collected.
- 1) Hair, skin, nails
- 2) Eye specimens
- 3) Body fluids
Name 2 types of agar used to grow fungi.
- SAB: Sabouraud's Agar
- PDA: Potato Dextrose Agar
- (High carb content, pH= 4- 6.5)
Name 2 antigens which can confirm diagnosis of fungi if present.
- Cryptococcal antigen
- Histoplasma antigen
What is used to dissolve cellular elements of fungi?
Name 3 clinical syndromes caused by fungi.
- Hypersensitivity Diseases
- Colonization of the host and resultant disease
Mycotoxicoses can be caused by
- Ergot Alkaloids (St. Anthony's fire, alpha adrenergic blockers, oxytocic agents)
- Psychotrophic Agents
- Accidental ingestion of non-edible mushrooms
Hypersensitivity due to fungi (mold):
1) Measure the degree of air pollution in "______"
2) Stimulates production of ______, leading to sensitized lymphocytes
3) Hypersensitivity pneumonitis including rhinitis, bronchial asthma, alveolitis, various forms of atopy
- 1) Fungal spore count
- 2) antibodies
Name 5 Types of Mycoses
- Superficial mycoses
- Cutaneous mycoses
- Subcutaneous mycoses
- Systemic mycoses
- Opportunistic infections
This type of mycoses infection is limited to the outermost layers of the skin and hair. It is usually a cosmetic response (no physical discomfort) that does NOT elicit a cellular response from the host and responds well clinically.
2 Superficial Mycoses that infect the stratum corneum.
- Pityriases versicolor
- Tinea nigra
Pityriasis versicolor and Tinea nigra affect the ____
stratum corneum (superficial mycoses)
Superficial mycoses hair infections involve which portion of the hair? What are 2 examples?
- Cuticle of hair
- Black piedra, white piedra
Causative agent of Pityriasis versicolor
Malassezia furfur (Pityrosporum orbiculare); part of normal flora, found in areas of the body rich in sebaceous glands
Malassezia furfur causes _____ and grows as _______
Pityriasis versicolor, budding yeast (hyphal forms occassionally seen)
Spaghetti & meatballs appearance when treated with KOH is diagnostic of ______
Name 2 symptoms of Pityriasis versicolor
- 1) Discrete hyper- or hypo-pigmented macular lesions, usually on trunk or arms
- 2) Dry, scaly, chlaky appearance
*Lesions fluoresce yellow-green under Wood's light
How do you distinguish the lesions of Pityriasis versicolor vs. other macular lesions?
They flouresce yellow-green under Wood's light.
What must be present in the medium to culture Pityriasis versicolor?
Name 4 things used to treat Pityriasis versicolor
- Topical azole cream
- 2% selenium sulfide lotion
- 20% Na thiosulfate lotion
- Oral ketoconazole or itraconozole (in extreme cases)
Type of mycoses that affects the skin, hair, and nails. It is generally restricted to keratinized layers.
Cutaneous mycoses (also known as dermatophytoses)
Which type of mycoses causes a cellular immune response, superficial or cutaneous?
3 Classifications of Dematophytes
- Anthrophilic: exclusively infect humans
- Geophilic: Soil inhabiting, infect both humans and animals
- Zoophlic: essentially pathogens of lower animals but animal-to-human transmission is not uncommon
Class of dermatophyte that almost exclusively infects humans
Anthropophilic (anthro = humans)
Class of dematophyte that inhabits the soil and infects both humans and animals
Class of dermatophyte that is essentially a pathogen of lower animals but anima-to-human transmission is not uncommon
3 Genera of Dermatophytes
- Trichophyton species (19)- infect skin, hair and nails
- Microsporum species (13)- infect skin and hair, rarely nails; easily identified because hairs fluoresce a bright green color when illuminated with a UV-emitting wood's light
- Epidermophyton floccosum- infect skin and nails, rarely hair
The dermatophyte trichophyton infects
skin, hair, and nails
The dermatophyte microsporum infects
skin and hair, rarely nails; hair fluoresces a bright green color when illuminated with a UV emitting wood's light
Dermatophyte epidermophyton floccosum infects
Skin and nails, rarely hair
Ringworm/ tinea is a _____ and thus infects what portion of the skin?
dermatophyte; keratinized layers
Dermatophyte infection that grows on outside of hair shaft
Dermatophyte infection that invades hair shaft
Anatomical sites of dermatophytes:
- ¢Tinea capitis: hair and scalp
- Exothrix: grows on outside of hair shaft
- Endothrix: invades hair shaft
- ¢Tinea barbae: infections of beard area
- ¢Tinea corporis: infections on the trunk
- ¢Tinea cruris: infections of inguinal area
- ¢Tinea pedis: infections of the foot
- ¢Tinea mannum: infections of the hand
- ¢Tinea unguium: involvement of the nails
Tinea pedis is what type of mycoses?
Cutaneous mycoses/ dermatophyte
Describe Tinea pedis. Where does it start, what are its symptoms?
Athlete's foot. Starts in lateral interdigital spades and may spread to dorsum of foot. Symptoms include itching, cracking, and maceration (softening of skin due to autolysis) between the toes
Describe Tinea cruris. Where does it start and what are its symptoms?
Usually involves anterior thighs and begins with scaling and irritation in the groin. (primarily seen in young men and may also effect women)
Describe Tinea corporis. What do the lesions look like?
Prominent edge with less inflamed center; scaly; can be single or multiple and may be hyperpigmented or itch.
Differential diagnosis includes eczema, psoriasis or annula erythema.
Symptoms of Tinea capitis.
Scaling with variable degree of erythema, inflammation, alopecia, and itching
Tinea Unguium causative agent.
Usually associated with nail thickening and discoloration.
Common in older individuals and involves fingernails or toenails.
3 Agents of Otomycosis
- Aspergillus niger
- A. fumigatus
- Mucor spp.
Superficial, chronic or subacute infection of outer ear canal
Otomycosis is an infection of what portion of the ear canal? Symptoms?
- Inflammation, scaling, itching and pain
3 Agents of Mycotic Keratitis
- Aspergillus spp.
- Fusarium spp.
- Candida spp.
Mycotic Keratitis is an infection of what?
Surface of cornea
Infection on the surface of the cornea
- Superficial: Oral and vaginal
- Intertrigonous areas and nails
Disease of superficial oral and vaginal surface as well as intertrigonous areas and nails.
5 Subacute Mycoses
Sporotrichosis, Chromomycosis, Phaeohyphomycosis, Mycetoma, Rhinosporidiosis are examples of?
1) How do you get infected?
2) Produces ulcerated nodule, sometimes associated w/ ____
3) May also disseminate Hematogenously to ___ and ___ in normal individuals
4) Found most often on _____
- Innoculation into skin
- Lymphatic spread
- Bone & CNS
Itraconazole, amphtericin B
Itraconazole and amphotericin B are used to treat
3 Causative agents of Chromomycosis
- Phialophora (Fonsecea) pedrosoi
- P. compacta
- P. verrucosa
- Cladosporium carrionii
What is produced in exudate?
- Chronic fungal infection that remains localized. Characterized by warty nodules, usually on the lower legs.
- Lesions usually enlarge and group with small ulcerations (black dots).
- Sclerotic bodies produced in tissue and exudate ("copper pennies")
Characterized by warty nodules, usually on the lower legs
What disease produces sclerotic bodies "copper pennies" in tissue and exudate, and black dot lesions?
Localized, chronic, noncontagious infection involving cutaneous and subcutaneous tissues
Mycetoma caused by filamentous fungi
Mycetoma due to filamentous fungi
Develops weeks to months after traumatic injury, tissue becomes indurated, abscesses develop and drain to sinuses
Mycetoma: Granulomatous tissue may invade as deep as?
Why is it important to distinguish between eumycetoma and mycetoma?
Different bacterial agents involved
What is tx for Mycetoma
- Ketoconazole, itraconazole, amphetricin B
- Continue for 10 months
Infections caused by the dematiaceous, or black mold containing melanin in its cell wall; dark.
Associated with allergic fungal sinusitis and brain abscesses
Tx of Phaeohyphomycosis
- Surgical draining or excision
- Epidural or brain abscesses = Amphotericin B
- Long term sinusitis = Itraconazole
- Meningitis = Voriconazole
What fungus is isolated from cerebrospinal fluid?
Exserohilum rostratum is found in
CEREBROSPINAL FLUID, plant debris, soil, and water
Infection with Exserohilum rostratum is uncommon and usually is restricted to
allergic sinusitis, keratitis, and localized soft-tissue infection (in rare cases, can be invasive in immunocompromised patients)
Serveral outbreaks of what fungus have been associated with black mold contamination in the past decade?
What species of exserohilum rostratum has been associated with meningitis due to contaminated glucocorticoid injections?
What species of Exserohilum rostratum was identified as the causes of an outbreak associated with contaminated water?
What is the usual drug of choice for infection with dematiaceous fungi?
An azole is the usual drug of choice for infection with?
Which drug, when given in high doses, has toxic effects? Now what drug is given instead
- Amphotericin B
If there is 100 mg of Voriconazole in the serum, how much is in the CSF?
- 50 mg in CSF
- Levels of drug in CSF are approximately 50% of serum levels, and levels in both CSF and serum are above the MIC for dematiaceous molds
Which drug can achieve substantial levels in cerebrospinal fluid and thus is used to treat Exserohilum rostratum, Posaconazole, Itraconazole, or Voriconazole?
Voriconazole is the only one that achieves substantial levels in CSF.
Invasive fungal sinusitis is associated with (3 things)
Malignancies, neutropenia, diabetes
If a patient has chronic sinusitis and it fails to respond to repeated courses of antibiotics, then you should consider?
Forward displacement of eyeball
Calcification of sinus on CT, allergic rhinitis, nasal polyps, asthma, and proptosis (in children) are all symptoms of?
Noninvasive fungal sinusitis (occurs in immunocompetent patients)
Tx of invasive fungal sinusitis
- Emergency surgery to remove necrotic and devitalized tissue
- Treatment with Amphotericin B
- Discontinue immunosuppression (ie. corticosteroids)
2 things that fluoresce under Wood's UV light
- Pityriasis versicolor