Microbiology Fungal Infections Flashcards
Pathogenic fungi:
- > 1000,000 fungal species
- > 1,5000 new species each year
- > 600 species reported from infections
- 200 on regular basis
- One new emerging ‘pathogen’ each month!!
Mycosis
Infection caused by fungi
Mycotoxicosis
Condition resulting from ingestion of food contaminated with metabolic products of Fungi
Description of fungi
Eukaryotic cells, but distinct from plants and animals
Fungi Types
Yeasts – single oval cells
Moulds- tube like cells (hyphae) and multicelled structures
Fungi Produce
Spores (used for identification)
How you get a fungal infection
- Exogenous
- Own source
- Traumatic implantation
Fungal infection types
• Superficial (derma)
• Subcutaneous (infection seen)
Systemic (seen in immunosuppressed patients)
Superficial fungal infection: Types and targets
Dermatophytes: skin, hair and Nails
Candidosis: Skin, Nail and Mucous membranes
Pityriaisis versicolor: Skin
Dermatophytes sources
Anthropophilic – Man
Zoophilic (animals)
Geophilic( Soil)
Dermatophytes: Trichophyton causes
Athletes foot
Cattle Ring worm
Scalp ringworm but can have bacterial infiltrations
Dermatophytes: Trichophyton causes size
Small in comparison
Dermatophytes Microsporum size
Large spores, thick walls
Dermatophytes Microsporum Causes
Microsporum canis (cat ringworm) Aldwanee: only seen on prepubescent
Dermatophytes epidermophyton floccosum causes
Athletes foot
Dermatophyte Malassezia furfur description
Yeast (lipid loving)
Carried in fatty Layer (greasy areas of skin)
Can cause nasty rashes
Superficial Candidosis
Mucosal infection Chronic mucocutaneous candidosis Nail infection Cutaneous infection Seen in poorly managed diabetes/Wet hands occupation related
Subcutaneous Infection Severe disease
Mycotoma – caused by funga growth which late stage erodes tissue and bone. Requires amputation.
Deep fungal Infection: Description
Large numbers of potential aetiological agents, most of which are ubiquitous environmental organisms
Deep fungal Infection: Acquired through
Inhalation
Deep fungal Infection: Common in
It’s a Life threatening disseminating infection, common in immunocomprimised patients
Deep fungal Infection: Examples
Mucoromycosis
Cryptpcococcosis
Candidosis
Aspergillosis
Mucoromycosis
White fluff mould on fruit
Colonises face
Very Rapid spread – no crosswalls or septae therefore fast transfer of nutrients
Mucoromycosis Rx
Fast acting anti-fungal (amphotericin)
Cryptococcosos
Fungal Meningitis (large polysaccarhide coat which may help with transfer.
Invasice candidosis
Most common deep fungal infection
Numerous manifestations, but few specific clinical signs
Invasice candidosis clinical signs
Oesophageal infection
Endocarditis
Disseminated candidosis
Osteomyelitis
Asperillosis
Omychomycosis (superficial) Cutaneous lesion Otitis externa (ear) Keratitis Aspergilloma (invasive)
Critical Factors for Successful treatment of Invasive fungal infection:
- Prompt recognition – few specific clinical signs difficult to diagnose
- Aggressive antifungal treatment
- Surgical resection of lesions?
- Reversal of immunosuppressions
Diagnosis
Direct microscopy
Culture and ID
Serology – antibodies and antigens
Molecular ID
Antifungals:
Echinocandins Polyenes (1mg/kg) Azoles Allylamines Flucytosine Griseofulvin
4 targets of anti-fungals:
- Cell wall
- Ergosterol
- Pyrimidine
- Spinder cell formation
