Introduction to Fungi Flashcards
What does the cell wall of a fungus contain?
Polysaccharides, often chitin or cellulose.
Does a fungi form spores?
Yes
Does a fungi contain chlorophyl?
No
What is the informal classification of fungi?
moulds yeasts or mushrooms
What is the cell type of a fungi?
They favour a unicellular habit
Eukaroyote
What kind of infections are by dermatophytes?
It is a pathogenic fungus that grows on body surfaces and causes ringworm and related diseases
What is the prefix for a ringworm infection?
tinea
What is the action of dermatophytes on keratin?
Moulds with a predilection to degrade keratin as a nutrient source.
What does a pityriasis versicolor cause on the skin?
Forms hyphae in infected skin
What do candida species infect?
Deep organs of patients with various types of immune dysfunction
What do aspergillus spp infect?
Infects deep organs of patients undergoing e.g chemotherapy, stem cell transplantation
What is a favourable micro-environment that will contribute to pathogenicity of a fungal infection?
Warm moist areas - encourages the growth of fungi on skin and mucous membranes. Broad spectrum antibacterial agents reduce competition for epithelial colonization sites in the gut. Immunosuppression of all types may create a window of opportunity for fungal invasion
Describe the immunosuppression of host defences
Iatrogenic (caused by medical examination or treatment)
Steroids
Anti-cancer chemotherapy
Solid organ transplantation
Disease processes - Aids Leukaemia
Endocrinopathies
Where are candida species commensal to?
The GI tract
What are risk factors for candidiasis?
Age, antibiotic therapy, endocrine disorders, immune defects, immune suppression, surgery
What are the diseases possible as a result of candida?
Oral infections
Vaginal infections
Skin infections
Nail infections
Oesophageal infections
Disseminated infections - in seriously immunocompromised patients
What is hyphae?
The fine branching tubes which make up the body (mycelium) of a multicellular fungus
Give examples of superficial candida infections
Mouth, vagina, penis, skin, nails
Give examples of a seriously immunocompromised host
Suffering from neutropenia, abdominal surgery, major burns
Give examples of human diseases caused by Aspergillosis
Simple asthma Asthma with eosinophilia
Aspergilloma
Invasive bronchopulmonary aspergillosis Disseminated aspergillosis.
How does infection by aspergillus spp occur?
They are moulds ubiquitous in the enviroment - infection occurs by inhalation of conidia
Define conidium
A spore produced asexually by various fungi at the tip of a specialised hypha
Aspergillus is said to be angioinvasive, what does this mean?
Penetrates the walls of the blood vessels.
What is the causative species for cryptococcosis?
Cryptocuccus……..(something)
What are the main diseases caused by cryptococcosis?
Pulmonary cryptococcosis
Meningitis (prevalent in AIDS patients)
What are the diagnostic methods for fungal infections?
Direct detection - histopathology (including direct smears and growth on selective medium) also the use of High resolution CT scans Detection of fungal antigens as well as antibodies to fungi
PCR for fungal DNA Culture of fungus from normally sterile site
What are the technical names for the three types of fungi?
Basidiomycetes (mushrooms) (cryptococcus)
Ascomycetes (candida, Aspergillus)
Zygomycetes (bread mould)
