Moulds Flashcards
What is the other species name for Dermatophytes? Name four of them.
Tinea.
T. pedis
T. corporis
T. cruris
T. copitis
Where do Dermatophytes cause infection?
Skin, hair and nails
Which specifies of Dermatophytes cause infection?
Trichophyton
Microsporum
Epidermaphyton
What are the typical sources of Dermatophytes?
Animal, human or soil
Describe the typical lesion caused by Dermatophytes.
Annular scaling patch with raised inflamed margin
What is mucormycosis infection caused by?
Rhizopus, Rhizomucor and mucor mould species
Name and describe the nutrition type of the moulds that cause mucormycosis.
Saphrophytic moulds = derive nutrition from dead/decaying matter
What are the typical causes of mucormycosis causing moulds?
Ubiquitous in soil, air particles and decaying matter (inoculation possible)
What are the risk factors for a potential mucormycosis infection?
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
What is the clinical presentation of mucormycosis?
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
What is the process of diagnosis with mucormycosis infections?
- Early diagnosis (be highly suspicious)
- Requires proof of tissue invasion by fungal hyphae
- Submission of necrotic tissue/aspirates/scrapings
- Microscopy and culture
- Histopathology
What is the treatment for a mucormycosis infection?
Important to reverse the underlying condition (diabetic ketoacidosis)
IV amphoteracin B (antifungal)
Surgical removal
What is the morbidity/mortality of mucormycosis?
Substantial once infection contracted
What type of infection does Aspergillus cause?
Invasive and non-invasive infections
What are the typical causes of Aspergillus infections?
Air, soil, dust, decaying organic matter.
Infection can be caused by inhalation of fungal spores
What is the hallmark of an invasive Aspergillus infection and where it most likely to occur in the body?
Hallmark: vascular invasion and pulmonary infarction
Lungs
What are the typical risk factors for Aspergillus infection?
Haematological malignancies
Transplant patients
People taking corticosteroids
What is the clinical presentation of an Aspergillus infection in an otherwise healthy host?
- Allergy (asthma, sinusitis, bronchopulmonary)
- Superficial / non-invasive (cutaneous, atomycosis and outer ear infection)
- Invasive (single/multiple organs)
What is the clinical presentation of an Aspergillus infection in an immunocomprimised host?
- Cutaneous
- Sinusitis
- Pulmonary
- CNS
- Disseminated infection
How do you diagnose an Aspergillus infection?
- Clinical features + radiological and lab investigations
(tissue biopsy, aspirate, microscopy, culture, histology) - Antigen detection is possible for INVASIVE disease (serum or bronchoalveolar)
What is the treatment for Aspergillus infection
- Systemic antifungal therapy (invasive disease) = Voriconazole
Name three medically important dimorphic fungi?
- Histoplasma Copsulatum (inhalation>colonization>dissemination)
- Sporothrix Schenekii
- Blastomyces Dermatitiolis
