Fungal Infections Flashcards
What type of organisms are fungi?
Eukaryotes
What is the composition of fungal cell walls?
Chitin
Which ribosomes are found in fungi?
80S
How do fungi reproduce?
Both sexually and asexually
Why are human fungal infections rare?
a) Fungi are not adapted to 37°C
b) Fungal enzymes work best in non-living substrates
c) Host defenses effectively prevent infection
What can make a person more susceptible to fungal infections?
HIV, diabetes mellitus, chemotherapy
what do moulds form?
Form hyphae and mycelium
How do yeasts reproduce?
Budding
What is a characteristic feature of dimorphic fungi?
Can exist as both yeast and mould
Which of the following fungi cause superficial infections without invading tissue?
Malassezia furfur
Dermatophytes use which substance as a nutrient?
Keratin
Aspergillus fumigatus primarily infects which organ?
Lungs
Why are antifungal drugs often toxic to humans?
Fungi are similar to human cells
Which antifungal drug is the most potent but also the most toxic?
Amphotericin B
What is the mechanism of action of azoles?
Inhibits ergosterol biosynthesis
Fungi store their genetic material in:
Several chromosomes inside a distinct nucleus
What best describes a saprophytic fungus?
It feeds on dead organic matter
How many species of fungi are estimated to colonize humans?
12
What are the main reasons fungal infections are rare in humans?
a) Fungi cannot grow at human body temperature
b) The immune system efficiently eliminates them
c) Their enzymatic pathways do not function well in human hosts
Opportunistic fungal infections are most common in:
Immunocompromised patients
Moulds grow by forming:
Hyphae
Yeasts are characterized by:
Single-celled, round or oval shape
Which of the following fungi exhibit dimorphic growth?
Coccidioides immitis
What triggers dimorphic fungi to switch between yeast and mould forms?
Temperature changes
Dermatophytes are unique because:
They produce keratinase to digest keratin
Which is the most common cause of deep or systemic fungal infections?
Aspergillus fumigatus
Which fungal infection is most commonly associated with patients who are severely neutropenic?
Aspergillosis
What is the primary route of transmission for deep/systemic mycoses?
Inhalation of spores
Which fungal infection can present with nodules, cavities, fibrosis, and chronic lung damage?
Coccidioidomycosis
Which of the following antifungal drugs inhibits glucan synthase, disrupting fungal cell wall synthesis?
Caspofungin
Azoles target fungi by:
Inhibiting lanosterol demethylase
Which antifungal drug is most commonly associated with liver toxicity?
Fluconazole
Cryptococcus neoformans is always resistant to:
Caspofungin
Mucormycosis infections are difficult to treat because:
They do not respond well to most antifungal drugs
what are the 3 types of fungi?
- Moulds
- Yeast
- Dimorphic
Which of the following is an example of a superficial mycosis?
Tinea versicolor
What type of mycosis extends into deeper skin layers, hair, and nails, but does not invade living tissue?
Cutaneous mycosis
Which of the following fungi is most commonly associated with systemic infections in immunocompromised individuals?
Candida albicans
Which class of antifungal drugs works by binding to ergosterol in the fungal cell membrane?
Polyenes (e.g., Amphotericin B)
What is the mechanism of action of azole antifungals?
Inhibiting lanosterol demethylase
What is a major side effect of Amphotericin B?
Nephrotoxicity (renal damage)
Which antifungal drug class targets the fungal cell wall by inhibiting β-glucan synthesis?
Echinocandins
example of dimorphic fungi
coccidioidomycoses
Candida albicans can form
true hyphae
What is the primary cause of ergotism
Claviceps purpurea
Which superficial fungal infection presents as a red macular rash without tissue invasion?
Tinea versicolor
Which type of fungal infection follows traumatic inoculation and may be locally invasive?
Subcutaneous mycoses
Subcutaneous fungal infections are most commonly found in which regions?
Tropics and subtropics
Which term describes the ability of Aspergillus fumigatus to invade blood vessels, leading to pulmonary hemorrhage?
Angiotropism
What is a hallmark feature of mucormycosis infection in the sinuses?
Black necrotic tissue
what are the types of antifungals
azoles
polyenes
name two azoles on the drugs list
fluconazole, clotrimazole
name two polyenes on the drug list
amphotericin B
nystatin
