Fungal infections

Question 1

What are the two main phyla of fungi?

Answer 1

Ascomycota,

Basidiomycota

Question 2

Which fungus out of the basidiomycetes causes the largest burden of disease?

Answer 2

Cryptococcus neoformans and Cryptococcus gatii-Causes cryptococcal meningitis

Question 3

What three types of illness do fungi cause?

Answer 3

Allergies Mycotoxicoses Mycoses

Question 4

Define mycotoxicosis.

Define allergy

Answer 4

ingestion of fungi and their toxic products e. g. aflatoxin.

allergic reactions to fungal products e.g. allergic bronchopulmonary aspergillosis (ABPA).

Question 5

What is known as the most carcinogenic natural compounds and what produces it?

Answer 5

Aflatoxin – Aspergillus flavus

Question 6

What are the symptoms of breathing mycotoxin

Answer 6

-breathing difficulties, dizziness, severe vomiting, diarrhoea, dehydration, distortions of colour depth etc

Question 7

Define mycosis.

Answer 7

Disease caused by fungi that is classified based on the level of tissue affected.

superficial, cutaneous and subcutaneous

Question 8

What are the four types of mycosis?

Answer 8

Superficial Cutaneous Subcutaneous Systemic

Question 9

What are superficial mycoses? Give some examples.

Answer 9

Mycoses that affect the skin and hair
No tissue is invaded so there is no cellular response.
Black piedra White piedra Dandruff
Tinea nigra

Question 10

What are cutaneous mycoses? Give some examples.

Answer 10

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)

Question 11

What are subcutaneous mycoses?

Answer 11

Chronic, localised infections of the skin and subcutaneous tissue following traumatic implantation of the aetiogic agent.

Question 12

What type of fungal infection is a big problem in transplant settings?

Answer 12

Inasive Aspergillosis

Question 13

What are the three types of candida infection that can occur in the immunocompromised?

Answer 13

Mucosal Systemic Superficial

Question 14

What are the three types of mucocutaneous candidiasis that occurs in people with HIV?

Answer 14

Oesophageal Vulvovaginal Oropharyngeal

Question 15

What are the main risk factors for systemic candida infections?

Answer 15

Chemotherapy Gut-related surgery Catheters

Question 16

What candida infections is an opportunistic one and another that is most common in new born and elderly?

Answer 16

Candida albicans- opportunisitic commensal

Superficial Candida- affects mouth, throat, scalp vagina etc

Question 17

What are the three main targets for antifungal therapy?

Answer 17

Cell membrane

DNA synthesis Cell wall

Question 18

How do antifungals that target the cell membrane work? Give some examples.

Answer 18

Fungal cell membranes contain ergosterol instead of cholesterol
Some antifungals inhibits ergosterol synthesis Examples: azole (itraconazole and fluconazole) Polyene antibiotics (Amphotericin B and Nystatin)

Question 19

How do antifungals that target DNA synthesis work? Give an example.

Answer 19

Pyrimidine analogues are used to interfere with DNA synthesis Example: Flucytosine (used for Cryptococcus)

Question 20

How do antifungals that target the cell wall work? Give an example.

Answer 20

They inhibit the assembly of fungal cell wall components such as glucans and chitin Example: Caspofungin (a type of Echinocandin)

Question 21

What components are found in fungal cell walls but not in mammalian cell walls?

Answer 21

Glucan and Chitin