015 Medical Mycology: Fungi and Fungal disease Flashcards
What is superficial Candida infection? Symptoms?
Yeast infection that normally breaks through irritated epithelial barriers in moist environments. It can cause oral thrush, vaginal infections and nappy rashes. It occurs to 75% of women.
When may candida undergo hyphal switch? How may this occur when someone is taking antibiotics?
During environmental changes such as increase in pH >7, serum presence, temperature changes, starvation. This can occur to someone taking B lactam antibiotics because they will have killed the Lactobacilli in the vagina. This raises the pH in the vagina, which stimulates the Candida yeast to switch to hyphae mode.
Where do superficial dermatophyte infections occur?
On keritinized tissues e.g nails, hair, skin. They land on these surfaces, lay down adhesin and secrete keratinase and assimilate oligopeptides/amino acids.
What are the 2 most common infections that occur in the immunocompetent?
Superficial Dermatophyte infections
Superficial Candida infections
Which is the most common organism causing superficial dermatophte infections? What does it cause?
Tychophyton rubrum (95%), causing ring worms. The spores lands in the central and start to grow outwards in mycelial network. the growing edge in the lesion becomes hyperinflammed.
Which is the interleukin responsible for the recruitment of neutrophils?
IL8
What are 3 common dimorphic fungi?
Histoplasma capsulatum
Blastomycosis
Coccidiodes immitis
What occurs in Blastomycosis infections?
Spores are inhaled; during phagocytosis by macrophages, the yeast at 36 degrees will replicate burst out of the cell.
What occurs in Coccidiodes immitis infections?
Spores are inhaled and inside the lungs it grows into hyphae which invade and replication in the lung tissue.
What occurs in Histoplasma capsulatum infections?
Spores are inhaled and during phagocytosis by neutrophils, it will replicate causing cell lysis.
Where do dimorphic fungi infections normally prevail?
In the US due to antimicrobial use. Not really in the UK
What is dimorphic fungi?
Fungi that can switch between the yeast and mould modes depending on environment.
If a bacteria has more mannan in its cell wall, what occurs to the body?
More inflammation occurs
What is the mortality rate of invasive aspergillosis and candida albicans?
40-50%
What is the main cause of invasive Candida albicans?
Use of antimicrobial antibiotics which disrupts gut microbiome
Immunosuppression
How may you diagnose invasive Candida albicans?
Blood culture of CT (nonspecific)
How do you diagnose invasive pulmonary aspergillosis?
Testing for galactomannan markers in the blood
Radiology of lung showing halo presence with hazy edge. Cannot use blood tests directly because it is located in the lung tissue.
Why are patients with bone marrow transplants more susceptible to pulmonary aspergillosis?
Neutropenia: neutrophils have antihyphal activity by surrounding conidia in airways and preventing its germination without acquiring uptake
When would mucoraceous mould infections most likely occur?
To diabetic patients with high iron levels
Name two AIDs defining invasive fungi diseases
Cryptococcus causing meningitis
Pneumocytis pneumonia
Both are yeast like infections
What type of fungi is Crytococcus neoformans?
Yeast like
Where are Saprophytes found?
On dead organisms
Describe the reproduction process of fungi? What is mycelial fragmentation?
Spores will develop into hyphae. Networks of hyphae will form mycelium. Mycelial fragmentation occurs when parts of mycelial network split off and form their own networks.
What is a very severe indication of invasive Candida albicans associated with very high mortality rate?
Candida opthalmitis in the eye
