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24 Cards in this Set
- Front
- Back
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Mycoplasms
Mycology |
study of fungi (eukaryotes)
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Mycoplasms
Cellular components of fungi |
-nucleus (membrane-bound)
-nucleolus -mitochondria -cell wall -cell membrane |
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Mycoplasms
Fungal cell wall components |
-glucan= rigidity
-mannan= antigenic diversity -chitin= diff. chemical composition than in bacteria |
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Mycoplasms
What is the significance of the sterols that are found in the fungal cell membrane? |
-most common sites for anti-fungal drugs
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Mycoplasms
Mycoses |
-diseases caused by fungi & yeasts
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Mycoplasms
Minimum size of fungi |
5 microns
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Mycoplasms
How many strains of fungi are there? |
-50,000-100,000 strains of fungi
-300 strains involved in medical problems -12-15 strains are major causes of disease |
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Mycoplasms
Reproductive Methods |
-mitosis or meiosis
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Myocplasms
Molds (= Mycelia) |
-multicellular fungi composed of many HYPHAE (= branched threads)
-TASKS= mycellia are subdivided into tasks |
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Mycoplasms
Spores (found in molds/mycelia) |
-nothing in common w/ bacterial spores
-no more resistant than the rest of the mycelum cell -serve in asexual/sexual multiplication |
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Mycoplasms
Yeasts |
-fungi
-have lost the ability to produce mycelium -asexual reproduction (BUDDING) |
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Mycoplasms
Dimorphic Fungi |
-2 morphological, temperature-related features:
-SAPROPHITIC (saprobic) form= grow like mycelium at 25C (room temp) -PARASTIC FORM= grow like yeasts at 37C (body/host temp) |
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Mycoplasms
Dimorphic Fungi: their significance? |
-if you have a dimoprhic fungus, it will grow differently (mycelium) at 25C than it will at 37C (yeast)
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Mycoplasms
Fungi Perfecti |
-fungi that are able to sustain sexual AND asexual reproduction (produce sexual & asexual spores)
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Mycoplasms
Fungi Imperfecti (= Deuteromycota) |
-fungi that are able to sustain ONLY asexual reproduction (produce asexual spores)
-cause most fungal diseases |
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Mycoplasms
Pre-disposing factors for fungal infections |
-immunocompromised hosts (e.g., AIDS patients)
-neutropenic patients--- low neutrophils (cancer pt's undergoing chemotherapy) -cancer pt's receiving radiotherapy -immunosuppressive drugs -post-transplantation patients (receive immunosuppressive organs) -Diabetic patients (incr. blood glucose--> fungal growth) -Pt's treated w/ broad-spectrum antibiotics (prolonged antibiotic treatment--> kills normal flora--> resistant bacteria remain & the niche once occupied by the dead flora is replaced by fungi) |
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Mycoplasms
Candida albicans (a yeast) |
-causes 1/3 of all (+) blood cultures
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Mycoplasms
What is behind the "steep rise" in the incidence of fungal diseases? |
-modern medicine
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Mycoplasms
Fungal-mediated disorders (4 types) |
1) Fungal poisoning= due to ingestion of poisonous mushrooms
2) Intoxication= ingesting food w/ mold-derived MYCOTOXINS (e.g., AFLATOXIN) 3) Fungal allergies= via airborne fungal inhalation (e.g, asthma due to aspergillus) 4) Mycoses= group of infectious pathogens |
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Mycoplasms
Aflatoxin |
-a mycotoxin
-highly carcinogenic (LIVER CANCER) --by product of Aspergillus flavus (a fungus) -found in food (esp. food kept in humid conditions) |
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Mycoplasms
Which fungus (fungal allergy) can cause asthma? |
-aspergillis
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Mycoplasms
Development of Mycoses (3 factors) |
-need all 3 to get mycoses
-1) Fungal contact -2) Infection (when & where the infection takes place is important) -3) Predisposing factors in the host (e.g., immunocompromised hosts) -mycoses depend on DIRECT host-pathogen interaction |
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Mycoplasms
Routes of Infection |
1) Injured Skin
2) Inhalation of Spores (diseased lungs) 3) GI & genitourinary tracts 4) Iatrogenic= catheters, surgery, etc. |
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Mycoplasms
Classification of fungal infections |
-fungal infections are organized according to the depth of the skin that they infect:
-1) Superficial Mycoses -2) Cutaneous Mycoses -3) Subcutaneous Mycoses -4) Systemic Mycoses= LIFE-THREATENING -Opportunistic Mycoses= most are systemic |
