Flashcards
Microbes & Disease - Lecture 17
Cards in this deck (33)
- 1What 3 ways can you contract a fungal infection?- Endogenous (fungi already within the body)
- Exogenous (fungi from outside the body invading)
- Traumatic innoculation (accidental if you like) - 2What type of fungi most commonly cause deep fungal infections?- Opportunistic
- Ubiquitous
- Saprophytes on decaying organic matter - 3Where does infection of opporutunistic deep fungal infection normally begin?- In the sinuses & lungs as a result of inhalation of airborne spores.
- Size dependent
- In some patients, infection may start in a wound e.g. burns patients. - 4How do deep fungal infections normally result in immunocompromised individuals?- Life threatening, disseminating infection
- 5Name the top 4 causers of fungal infection. Of these 4, which 2 are emerging pathogens?- Aspergillus
- Zygomycetes
- Scedosporium*
- Fusarium* - 6How many Aspergillus spores does a healthy individual inhale every day with no effect?300 - 400
- 7Name 4 species of Aspergillus which cause deep infections.- A. fumigatus
- A. flavus
- A. terreus
- A. niger - 8How do Aspergillus appear?- Sporing heads
- Constantly squeezing out new spores. - 9How do A. fumigatus appear?- Spores & vesicles
- 10What type of infections are caused by the following species of Aspergillus? A. fumigatus, A. flavus, A. niger, A. terreus.- A. fumigatus = Deep infections & an allergen
- A. flavus = Ear, eye, deep & allergen.
- A. niger = Skin, Ear, eyes, deep & allergen.
- A. terreus = Skin, Ear, Eyes, deep & allergen. - 11Why do all species of Aspergillus behave as an allergen?- All produce fast numbers of dry spores.
- Cause allergic reactions. - 12Give some examples of deep infections caused by Aspergillus.- Necrosis of facial tissue
- Fungus growing in lungs
- Aspergilloma which can become invasive. - 13What are Zygomycetes otherwise known as?Mucoraceous moulds
- 14Describe the morphology of Mucoraceous moulds.- Broad
- Aseptate
- Vegetative hyphae
- Asexual spores/ sporangiospores
- Made inside sporangia cells held up on stalks known as sporangiophores.
- Rhizoids or root-like structures may be formed.
- Columella or dome- shaped septum is formed at the base of the sporangium.
- Sporangia often release spores and collapse in characteristic ways. - 15Name 2 species of Zygomycetes.- Lichtheimia corymbifera
- Cunninghamella bertilitiae - 16What is the word used to describe infections caused by Zygomycetes?- Mucormycosis/ Zygomycosis
- 17What property enables species of Zygomycetes to cause infection in both man and animals?Thermotolerant
- 18How would you describe the mycelium of Zygomycetes?- Luxuriant, fast-growing, aerial mycelium
- 19Why is an infection with Zygomycetes often termed Mucormycosis?Because most pathogens of Zygomycetes are in the order Mucorales.
- 20Since mucormycosis spreads so rapidly, what can be the result?Fatality without treatment
- 21Give 3 clinical presentations of Mucormycosis.- Mucoraceous lesion of hard palate
- Rhinocerebral mucormycosis
- Mucoraceous infection of the eye - 22What species of Zygomycetes has a sporangium which pops a cork when it is ready to release it's spores?Saksenaea vasiformis
- 23Scedosporium spp. is clinically indistinguishable from what other type of infection?Invasive aspergillosis
- 24What is a risk factor to contracting an infection with Schedosporium spp.?- Neutropenia
- 25Fusarium spp. is clinically very similar to which other infection?Aspergillosis
- 26What % of infected individuals with Fusarium spp. present with cutaneous lesions?70%
- 27What % of infected individuals with Fusarium spp. present with positive blood culture?50 - 70%
- 28Is Fusarium spp. water borne?Yes
- 29What is meant by cutaneous lesions when infected with Fusarium spp.?- Fusarium travels in the blood & migrates to the skin to try and grow out through the skin.
- 30Where is the fungus Histoplasma capsulatum particularly prevalent?- North & Central America
- Eastern & Southern Europe
- Parts of Africa
- Eastern Asia
- Australia - 31Describe the multistate fungal meningitis outbreak, USA.- Fungus found in at least 50 vials of an injectable steroid medication.
- Manufactures at a specialist compounding pharmacy in Massachusetts - NECC.
- 3 batches involved
- 17,700 vials sent to 23 states
- 14,000 may have received contaminated steroid
- 720 cases
- 48 deaths - 32What are 4 critical factors associated with successful treatment of invasive fungal infection?- Prompt recognition (difficult because few specific clinical signs > difficult to diagnose)
- Aggressive anti-fungal treatment
- Reversal of immunosuppression
- Surgical resection of lesions - 33How do the following anti-fungal treatments work? - Amphotericin B - Caspofungin - Voriconazole - Posaconazole - Itraconazole- Amphotericin B = Targets plasma membrane > ergosterol biosynthes & lipid formulation.
- Caspofungin = Targets cell wall > beta-1,3-glucan synthase.
- Voriconazole = Targets plasma membrane > ergosterol biosynthesis.
- Posaconazole = Targets plasma membrane for ergosterol biosynthesis.
- Itraconazole = Targets plasma membrane for ergosterol biosynthesis.
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- Invasive Fungal Infections
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