Fungal infections Flashcards
What are the two main phyla of fungi?
Ascomycota,
Basidiomycota
Which fungus out of the basidiomycetes causes the largest burden of disease?
Cryptococcus neoformans and Cryptococcus gatii-Causes cryptococcal meningitis
What three types of illness do fungi cause?
Allergies Mycotoxicoses Mycoses
Define mycotoxicosis.
Define allergy
ingestion of fungi and their toxic products e. g. aflatoxin.
allergic reactions to fungal products e.g. allergic bronchopulmonary aspergillosis (ABPA).
What is known as the most carcinogenic natural compounds and what produces it?
Aflatoxin – Aspergillus flavus
What are the symptoms of breathing mycotoxin
-breathing difficulties, dizziness, severe vomiting, diarrhoea, dehydration, distortions of colour depth etc
Define mycosis.
Disease caused by fungi that is classified based on the level of tissue affected.
superficial, cutaneous and subcutaneous
What are the four types of mycosis?
Superficial Cutaneous Subcutaneous Systemic
What are superficial mycoses? Give some examples.
Mycoses that affect the skin and hair
No tissue is invaded so there is no cellular response.
Black piedra White piedra Dandruff
Tinea nigra
What are cutaneous mycoses? Give some examples.
Produce keratinases: capable of hydrolysing bacteria -causes inflammation due to host response by metabolic by products Examples: Microsporum and Trychopyton. other examples: -Tinea capitis (head/neck) -Tinea pedis( feet)(highly contagious) -Tinea corporis (body) Tinea= worm -Tinea cruris (groin) -Tinea unguium (finger/toenails)
What are subcutaneous mycoses?
Chronic, localised infections of the skin and subcutaneous tissue following traumatic implantation of the aetiogic agent.
What type of fungal infection is a big problem in transplant settings?
Inasive Aspergillosis
What are the three types of candida infection that can occur in the immunocompromised?
Mucosal Systemic Superficial
What are the three types of mucocutaneous candidiasis that occurs in people with HIV?
Oesophageal Vulvovaginal Oropharyngeal
What are the main risk factors for systemic candida infections?
Chemotherapy Gut-related surgery Catheters
What candida infections is an opportunistic one and another that is most common in new born and elderly?
Candida albicans- opportunisitic commensal
Superficial Candida- affects mouth, throat, scalp vagina etc
What are the three main targets for antifungal therapy?
Cell membrane
DNA synthesis Cell wall
How do antifungals that target the cell membrane work? Give some examples.
Fungal cell membranes contain ergosterol instead of cholesterol
Some antifungals inhibits ergosterol synthesis Examples: azole (itraconazole and fluconazole) Polyene antibiotics (Amphotericin B and Nystatin)
How do antifungals that target DNA synthesis work? Give an example.
Pyrimidine analogues are used to interfere with DNA synthesis Example: Flucytosine (used for Cryptococcus)
How do antifungals that target the cell wall work? Give an example.
They inhibit the assembly of fungal cell wall components such as glucans and chitin Example: Caspofungin (a type of Echinocandin)
What components are found in fungal cell walls but not in mammalian cell walls?
Glucan and Chitin
