Medical Mycology Flashcards
medical mycology
Branch of mycology concerned with the study of fungi which cause diseases in humans
What do fungi infect the most ?
Plants –> 70% plant diseases
Human are relatively resistant
How many are there fungal species?
100,000 species but only 200 pathogenic for humans
what are the opportunistic fungi?
Cryptococcus - Cryptococcosis
Candida- candidiasis
Aspergillus - Aspergillosis
Pneumocystis - pneumocystis
why interest in medical mycology?
Increased frequency of infection, awareness , more invasive medical procedures, increased use of immunosuppressive drugs, better laboratory diagnostic tools
what’s a fungus
eukaryotic heterotrophic organism, lacking chlorophyll but obtain nutrients by absorption and reproduces by spores
( yeast, mushrooms, lichens)
saprophytes
obtain food rom decaying matter
parasites
feed on host, harm to host
Symbionts/mutualistic
live in close association with an organism of another species , mutual benefit
commensals
live in close association with an organism of another species, unilateral benefit
Characteristics of fungi
- multicellular organisms (not yeast)
- Eukaryotes
- Heterotrophs
- cell walls ( chitin, glucans, gp)
- reproduce by spores
- need moist , warm places to growth
How do fungi divide?
intranuclear division (nuclear envelope remains intact during mitosis )
Morphologies of Fungi
- Moulds( Filamentous -hyphae)
- Yeasts (Unicellular cells that bud)
- Filaments (Pseudohyphae) - Dimorphic (under some conditions to form filaments)
- grow as moulds in nature and lab culture
- grow as yeast in tissue infection
Fungi organism groups
Mycornmycetes, basidiomycetes, pneumocystidiomycetes , saccharomycetes , euascomycetes
How to classify human fungal pathogens?
- True(primary pathogens): superficial , cutaneous, subcutaneous , systemic
- Opportunistic pathogens
What are the symptoms of Pulmonary blastomycosis ?
Anorexia, weight loss, cough, haemoptysis , night sweating
Diagnosis of fungal infections
- Patients history, clinical signs and symptoms
- Skin test, serology, microscopy of tissues samples and results of culture from clinical samples ( sputum,pus, blood, spinal fluid, bronchioalveolar lavage , urine, tissue biopsy or skin scrapping)
Microscopic test
- Conidia or hyphae identification
Dyes/Stains used : GMS, PAS stain , Calcofluor white ( chitin )
Culture test
SAB ( 3% dextrose +low pH)
antibacterial agents
Potato dextrose agar used
Serology test + antigen test
-Detection of antifungal antibodies : agglutination, immunodiffusion, complement fixation, IF,ELISA
Skin test
Molecular test
- Sensitivity to fungal antigens
- DNA Hybridisation, PCR
