16. Mycology

Question 1

Name the 3 broad categories of fungi:

Answer 1

1. Yeast
2. Moulds
3. Dimorphic fungi

Question 2

Name 2 key yeasts.

Answer 2

1. Candida
2. Cryptococcus

Question 3

What medium is most commonly used to culture yeasts?

Answer 3

Sabouraud’s agar (with or without antibiotics)

Question 4

What is the importance of knowing the different species of candida/aspergillus?

Answer 4

• allows us to know the difference in fungal resistance against anti-fungals

Question 5

What is the most common species of Candida?

Answer 5

Candida albicans
- common in mucosal areas e.g. oral cavity, GIT
- but also found on skin, tables & keyboards => environment tolerant, resistant to lots of anti-septic agents => environment becomes candida reservoir

Question 6

What is the latest species of Candida that is causing multi-resistance?

Answer 6

Candida auris

• resistant to most anti-fungals
• some are completely resistant => anti-fungals ruled out as an option completely
• not common in sg, usually imported via foreigners
• usually in pxs w many other medical probs

Question 7

What is a common prophylactive anti-fungal used for candida?

Answer 7

fluconazole

• commonly used in cancer/oncology pxs to kill off all candida albicans
• side effect, candida gets superseded and overgrown by another species (that is naturally resistant to fluconazole)

Question 8

What is Aspergillosis?

Answer 8

• most impt mould in medical world
• super common, found in the air ard us, prolly breathing this in everyday any moment
• harmless to normal ppl
• opportunistic disease in immunocompromised pxs

Question 9

What is invasive aspergillosis?

Answer 9

Refers to actively invading aspergillosis into systems causing problems in
- pulmonary
- sinonasal
- central nervous system
- endocarditis
- renal

common in oncology ward
- in cancer/leukemia pxs / immunocompromised aft transplant procedures
- once invaded => prognosis not good

Question 10

What is Zygomycosis otherwise known as?

Answer 10

“Lid Lifter” mould
- cuz they grow rlly rlly quickly n aggressively => push agar plate lids off

Question 11

Name some important Zygomycosis species.

Answer 11

1. Mucor spp
   - appears green on Sabouraud’s agar
2. Rhizopus spp

Question 12

Name the 4 key moulds.

Answer 12

1. Aspergillus
2. Fusarium
3. Trichophyton
4. Mucor

Question 13

What is Rhinocerebral Mucormycosis?

Answer 13

Aka ‘nose/sinus & brain’ mucormycosis - infection in the sinuses that can spread to the brain.

• occurs in diabetics/immunocompromised pxs, when infected by zygomycosis/filamentous fungi.
• causes destructive lesion of maxillary sinus/mouth region

Question 14

What is dimorphic fungi?

Answer 14

TLDR: fungis that can exist in both mould and yeast form
- yeast form at body temp (37 deg cel)
- mould form at ambient temp (25-30 deg cel)