Moulds

Question 1

What is the other species name for Dermatophytes? Name four of them.

Answer 1

Tinea.

T. pedis
T. corporis
T. cruris
T. copitis

Question 2

Where do Dermatophytes cause infection?

Answer 2

Skin, hair and nails

Question 3

Which specifies of Dermatophytes cause infection?

Answer 3

Trichophyton
Microsporum
Epidermaphyton

Question 4

What are the typical sources of Dermatophytes?

Answer 4

Animal, human or soil

Question 5

Describe the typical lesion caused by Dermatophytes.

Answer 5

Annular scaling patch with raised inflamed margin

Question 6

What is mucormycosis infection caused by?

Answer 6

Rhizopus, Rhizomucor and mucor mould species

Question 7

Name and describe the nutrition type of the moulds that cause mucormycosis.

Answer 7

Saphrophytic moulds = derive nutrition from dead/decaying matter

Question 8

What are the typical causes of mucormycosis causing moulds?

Answer 8

Ubiquitous in soil, air particles and decaying matter (inoculation possible)

Question 9

What are the risk factors for a potential mucormycosis infection?

Answer 9

Opportunistic infection…

• Poorly controlled Diabetes Mellitus (other metabolic acidosis)
• Prolonged neutropaenia (haemopoeitic malignancy / stem cell transplant)
• Can occur in healthy people cutaneously following traumatic innoculation

Question 10

What is the clinical presentation of mucormycosis?

Answer 10

Hallmark: necrotic black eschar (scab-like dead tissue / sloughed off skin)

• Angioinvasion (invasion of blood vessels with thrombosis and infarction)
• Agressive infection and progression
• Acute onset
• Rhino-orbital-cerebral infection (most common) (starts in paranasal sinuses and spreads through palate, nose, skull etc)
• Infection of GIT, pulmonary and cutaneously

Question 11

What is the process of diagnosis with mucormycosis infections?

Answer 11

• Early diagnosis (be highly suspicious)
• Requires proof of tissue invasion by fungal hyphae
• Submission of necrotic tissue/aspirates/scrapings
• Microscopy and culture
• Histopathology

Question 12

What is the treatment for a mucormycosis infection?

Answer 12

Important to reverse the underlying condition (diabetic ketoacidosis)
IV amphoteracin B (antifungal)
Surgical removal

Question 13

What is the morbidity/mortality of mucormycosis?

Answer 13

Substantial once infection contracted

Question 14

What type of infection does Aspergillus cause?

Answer 14

Invasive and non-invasive infections

Question 15

What are the typical causes of Aspergillus infections?

Answer 15

Air, soil, dust, decaying organic matter.

Infection can be caused by inhalation of fungal spores

Question 16

What is the hallmark of an invasive Aspergillus infection and where it most likely to occur in the body?

Answer 16

Hallmark: vascular invasion and pulmonary infarction

Lungs

Question 17

What are the typical risk factors for Aspergillus infection?

Answer 17

Haematological malignancies
Transplant patients
People taking corticosteroids

Question 18

What is the clinical presentation of an Aspergillus infection in an otherwise healthy host?

Answer 18

• Allergy (asthma, sinusitis, bronchopulmonary)
• Superficial / non-invasive (cutaneous, atomycosis and outer ear infection)
• Invasive (single/multiple organs)

Question 19

What is the clinical presentation of an Aspergillus infection in an immunocomprimised host?

Answer 19

• Cutaneous
• Sinusitis
• Pulmonary
• CNS
• Disseminated infection

Question 20

How do you diagnose an Aspergillus infection?

Answer 20

• Clinical features + radiological and lab investigations
  (tissue biopsy, aspirate, microscopy, culture, histology)
• Antigen detection is possible for INVASIVE disease (serum or bronchoalveolar)

Question 21

What is the treatment for Aspergillus infection

Answer 21

• Systemic antifungal therapy (invasive disease) = Voriconazole

Question 22

Name three medically important dimorphic fungi?

Answer 22

1. Histoplasma Copsulatum (inhalation>colonization>dissemination)
2. Sporothrix Schenekii
3. Blastomyces Dermatitiolis