Fungal pathogens Flashcards
properties of fungi
- Eukaryotic
- Single celled to macroscopic
- Reproduce asexually + sexually with spores
What are the growth forms of fungi
Hypha - Moulds
Yeast cells - yeasts
What are the 3 lifestyles of fungi
- Saprophytes - decaying organic matter
- Plant pathogens
- Animal pathogens
What are the 3 type of fungal disease
- Superficial infection - skin, hair, nails etc
- Subcutaneous infection - subcutaneous tissue
- Systemic infection - deep-seated organs affected
What are dermatophytes
Group of moulds causing superficial infections
- originate in soil, animals or humans
Athletes foot
Tinea pedis
- Typical cause Trichophyton rubrum
- itching, flaking, dry skin
Fungal nail infection
Tinea unguium
- Typical cause Trichophyton rubrum + T.interdigitale
- Thickening, discolouring, dystrophy
Jock itch
Tinea cruris
- Typical cause T.rubrum
- Itching, scaling, erythematous plaques
Scalp ringworm
Tinea capitis
- Mainly seen in pre-pub children
- scaly patches, black dots, severe inflammation
What are Kerion celsi
Inflamed lesions usually from zoophilic dermatophytes
Ringoworm
Tinea corporis
- Typical cause zoophilic/anthropophilic dermatophytes
- Circular erythematous plaques
- May invade follicle
What is topical antifungal therapy + 3 examples
Used for mild diseases
- Terbinafine
- Clotrimazole
- Miconazole
How to treat tinea capitis?
Use systemic oral antifungals such as Griseofulvin, terbinafine, itraconazole
What is Pityriasis versicolor
- Hyper/hypo pigmented lesions
- between puberty and middle age
What is Malassezia
- Genus of yeasts
- part of normal skin flora in humans
- Causes Pityriasis versicolor
Diagnosis of Pityriasis versicolor
Culture looks like spaghetti and meatballs
- Presence of both yeast cells and hyphal segments
Treatment of Pityriasis versicolor
Topical antifungals
- Clotrimazole
- If fails then oral fluconazole
Candida
Large genus of yeasts
- colonises mucosal surfaces and GI tract
- Causes thrush
- Cause of systemic infection if present in blood
4 types of superficial candida infection
- Acute pseudo-membranous
- Chronic atrophic
- Angular cheilitis
- Chronic hypoplastic
Candida Vulvovaginitis
Inflammation of vaginal epithelium - burning sensation, Pruritis
Diagnosis and treatment of superficial candidosis
Diagnosed with culture and antifungal sensitivity testing
- Oral azoles highly effective
Why not give oral azoles to pregnant women
Increases the risk of teratologies in the foetus
- Use topical azoles
- TTT treat thrush topically
Systemic Candidosis
Candida sp can infect any organ in the body.
- Defined by site of infection
- Candida albicans most common
Candida oesophagitis
Mainly in HIV
- pain swallowing/ eating
- Diagnosed by endoscopy
Candidaemia
Candida in blood
- Very rare, treated with antifungal treatment
Candida chorioretinitis and endophthalmitis
Causes occular candidosis
Candida endocarditis
Vegetations seen on the heart valves, fever, fatigue
- Treated with valve replacement
UT Candida infection
Ascends from genital tract infection
- More common in women, diabetics, ICU patients
- Candiduria can be used
What is Candiduria and why is it necessary
Used to treat UT Candida infection
- Isolation of Candida from urine
- Used as there are few antifungals secreted in urine
Candida peritonitis
- Perforation of bowel during peritoneal dialysis
- Diagnosis by culture of Candida in peritoneal fluid
- Fever, nausea abdominal pain
Diagnosis and Treatment of Systemic Candidosis
- Diagnosis by culture
- Treatment depends on they type of Candida, sensitivity and severity
- Echinocandins, Azoles
What is Aspergillus
Genus of moulds - filamentous fungi
- produce spores
- Usually colonises airways
Aspergillosis
Broad term based on the reaction to inhaled Aspergillus
Aspergilloma
Non invasive/ space occupying fungal ball in lung cavity
- If the ball breaks it can cause haemoptysis and can be fatal
Allergic Bronchopulmonary aspergillosis
- Usually in patients with asthma and CF
- Airway inflammation, breathlessness, loss of lung function
- IgE and G reaction to aspergillus
Chronic pulmonary aspergillosis
- COPD
- chronic respiratory symptoms
- positive for aspergillus IgE
Invasive aspergillosis
- Angioinvasion of lung tissue
- Haematological malignancies
Aspergillosis, diagnosis and treatment
Diagnosis - culture, serology Treatment: Aspergilloma - resection Allergic asp - steroids/antifungals CPA and invasive asp - antifungals - azoles
