Antifungals

Question 1

Name the fungi that causes common infection of skin hair and nails

Answer 1

Dermatophytes

Question 2

Dermatophytes

Answer 2

• Health and immunocompromised are affected
• Dont colonise live tissues, instead keratinised areas e.g. nails and outer skin
• Use keratinases and elastase as virulence factors

Question 3

What is the treatment against dermatophytes?

Answer 3

• Topical administration usually
• Oral medication - severe infections, when topical medications have not worked, adults only
• Terbafine/itraconazole

Question 4

Name 3 fungi causing systemic fungal infections

Answer 4

• Cryptococcus neoformans (meningitis)
• Aspergillius fumigatus (aspergillosis of the lung)
• Pneumocystis jiroveci (pneumocystis pneumonia)

Question 5

Which groups are affected by systemic fungal infections?

Answer 5

Immunocompromised

Question 6

What is crypto coccus neoformans?

Answer 6

• Inhaled opportunistic pathogen
• Encapsulated yeast
• Contracted from he environment

Question 7

What does cyrtococcus neoformans infection cause?

Answer 7

• Meningitis
• Cryptococcosis of the lungs
• Often both secondary infection with HIV

Question 8

What is the treatment of crypto coccus neoformans infection?

Answer 8

• For meningitis: 2 weeks IV amphotericin B

* For non CNS infection: fluconazole or flucytosine

Question 9

What are the reactions caused by aspergillus fumigatus?

Answer 9

• Allergic bronchopulmonary aspergillosis
• Invasive pulmonary aspergillosis
• Aspergilloma

Question 10

What is allergic bronchopulmonary aspergillosis?

Answer 10

• Allergic reaction to fungal infection

* Associated with cystic fibrosis and asthma

Question 11

What is invasive pulmonary aspergillosis?

Answer 11

• Becomes systemic and spreads throughout the body (via bloodstream)
• Common in immunocompromised

Question 12

What is aspergilloma?

Answer 12

• An encapsulated fungal ball that develops in an area of past lung disease or lung scarring that has left the tissue vulnerable
• e.g. abscess or tuberculosis

Question 13

What is the treatment of allergic bronchopulmonary aspergillosis

Answer 13

Prednisolone

Question 14

What is the treatment of invasive pulmonary aspergillosis?

Answer 14

• Voriconazole

* Amphotericin B

Question 15

What is the treatment of aspergilloma?

Answer 15

• No treatment unless bleeding occurs

* If bleeding occurs then surgery

Question 16

What are the symptoms of pneumonia?

Answer 16

• Fever
• Cough
• Shortness of breath, rapid breathing

Question 17

What is the treatment or prophylaxis of pneumocystis jiroveci?

Answer 17

Trimethoprim-sulfamethoxazole (anti-folate)

Question 18

What is mucormycosis?

Answer 18

• Opportunisitc infection
• Environmental fungi found in soil, compost, animal dung
• Harmless in immune-competent
• Respiratory and sinus infections in immune-compromised
• seen in COVID patients

Question 19

What are the azoles?

Answer 19

• Inhibitors of 14-methylsteol alpha-demethylase which produces ergosterol
• Fluconazole
• Miconazole
• Econazole

Question 20

What is ergosterol?

Answer 20

An essential component of the fungal plasma membrane (it is the equivalent of the cholesterol)

Question 21

Azasterols

Answer 21

delta 24- sterol methyltransferase inhibitor (not really specific enough)

Question 22

What is the mechanism of action of terbafine?

Answer 22

Squalene 2,3- epoxidase inhibitor (also involved in the cholesterol pathway so bad effects)

Question 23

What is the drawback of the azoles?

Answer 23

Cross resistance

Question 24

What is amphotericin B?

Answer 24

• Binds to ergosterol
• It has a hydrophobic and a hydrophilic side
• Creates a pore in the fungal membrane
• Disrupts the plasma membrane potential and the cell dies

Question 25

What is ambisone

Answer 25

• Amphotericin B is enclosed as part of the liposome

* Improves delivery and reduced toxicity