Intro to Fungi Flashcards
Opportunistic systemic mycoses?
Candida albicans: oral/esophageal, systemic and vaginal
Cryptococcus neoformans: brain
Aspergillus fumigatus: lungs
Superficial mycoses: feet
When are fungi most prominent?
Immune-compromised people
What is a fungus?
A chemo-organotrophic eukaryotes that lacks chlorophyll and forms spores. Its cell wall.contains polysaccardies, often chiron or glucagon and it absorbs nutrients. Its membrane contains ergosteril as the major sterol. Classification based in morphology
Structure of a fungi?
Forms a mycelium
Hypha, hyphal branch, and the hyphal apex
Forming a conidiophore with chains of conidia that spread the fungi
Name the fungal groups which cause disease in humans?
Basidiomycetes (mushrooms)
Ascomycetes (yeast)
Zyginycetes (bread mould)
Stricture of ascomycetes?
Ascospores contained within a sac
Zygomyctes structure?
Rough-walled zygote contains one or more zygospores
Reproduction systems of fungi?
Budding or unicelluar division?
Non-fatal diseases caused by fungi?
Athlete’s foot: epidermophyton and mucrosporum
Thrush: candida
Fatal diseases?
Candida can infected deep organs
Aspergillys so infect deep organs
Host factors contribute to pathogenicity of fungal infections?
Favourable microenvironment (warm and moist) Broad-spectrum antibacterial create space for epithelial colonisation Immunosuppression created window of opportunity
Immunosuppression of host defences?
Iatrogenc: steroids, chemo and transplantation
Diseases: AIDS, leukaemia and endocrinopathies
Candidiasis?
Commensal to GI
Risk factors: age, antibiotic therapy, endocrine disorder, immune defect, immune suppression and surgery
Candida causing human diseases?
Oral, vaginal, skin, nail, esophageal, urinary and disseminated
Oral candidosis?
Cutaneous/superficial
Caused by candida
Increasing cases
Attributed to immunocompromised patients
Pre-disposing factors:
- local: antibiotics, dentures, corticosteroids and radio
- general: drugs, age, endocrine, immunity, nutritional deficiency and smoking
Symptoms and presentation of OPC?
White plaques resemble milk curd of buccal mucosa and less common in tongue or gums
Symptoms may be absent or dryness, loss of taste and pain on swallowing
Classification of oral candidosis?
Pseudomembranous (tongue) Erythmatous (hard palate) Hyperplatsic (inflammation tongue( Angular cheiltis (edge of mouth) Chronic mucocutaneous candidosis
Oral thrush?
Pseudomembranous (roof)
Oral candida
Glossitis and angular cheiltis
Chronic atrophic candida?
Epiglotis
Candida oesophagitis
Oesophagus
Candida onychimycosis?
Nails
Chronic mucocutaneous candida?
Face
Arise with an unusual combi of endocrine and immune dysfunction
(APECED)
Diagnosis of oral candidosis?
Direct smear: scraped and applied to microscope slide
Swab: inoculation of swap into growth medium
Oral rinse: inoculated onto selective medium
Imprint culture: sterile foam applied to mucosa and placed onto agar plate
Biopsy
Direct smear?
Periodic acid shiff: staining of gluco____
Vaginal smear: calcofluor white stain
Antifungals and their targets?
Traziles and allyamines: target steril
Echinocandins: target wall
Polyenes: target membrane
Flucytosine: target DNA synth
Antifungal problems?
Spectrum of activity Static or cidal IV or oral Resistance Cost
Polyenes?
Amphotericin B (topical, IV, lozenge, ointment, and oral suspension Nystatin (topical, particle and oral suspension)
Azoles?
Clotrimazile and fluconazole (topical)
Fluconazole and itraconazole (oral and IV)
Echinocandins?
Anidulafungin, caspofungin and micafungin (IV)
Antiseptics?
Chlorhexidine
