M9: Candida, Other fungi & Actinomyces Flashcards
What are the 2 main groups of fungi?
- Moulds
- Yeast
Fungi can have 3 different characteristics, what are they?
- Saprophytes (in soil/decaying plant material)
- Parasites
- Commensals (no harm)
Give some features of moulds (2)
- Mycelial fungi
- Branching filaments which form interwoven mass
- Reproduce by means of spores
Give some features of yeasts (2)
- Predominately unicellular
- Reproduce by budding
What are dimorphic fungi?
Either mycelial or yeast phase depending on growth conditions
What does form and severity of a fungal disease depend on? (4)
- Degree of exposure
- Site of exposure
- Method of entry into body
- Level of immunocompetence of host
What are the 3 types of fungal infection?
- Superficial mycoses
- Subcutaneous mycoses
- Systemic mycoses
What does mycoses mean?
A disease caused by a fungus
Where can superficial mycoses occur? (4)
- Skin
- Hair
- Nail
- Mucous membranes
What is the most common type of fungal infection?
Superficial mycoses
What is ringworm?
A complex of disease caused by moulds
What are Dermatophytes?
- Fungi that affect keratinous tissues of hair, nail & skin
- As they can colonise and digest keratin
Where can subcutaneous mycoses occur? (3)
- Skin
- Subcutaneous tissues
- Bone
How doe systemic mycoses occur?
Generally result from inhalation of airborne mould spores
80-90% of superficial mycoses is caused by what?
C.albicans
Generally why do fungal infections arise?
Infection often arises due to deficiencies in the host rather than because of any inherent pathogenic properties of the fungus
How are fungal infections diagnosed?
Combination of clinical observation & lab investigation
How do ringworm infections spread? (2)
- Direct contact
- Indirect contact
What are some clinical presentations of ringworm infections? (4)
- Irritation
- Erythema
- Oedema
- Vesiculation
When does carriage of superficial candidosis increase? (2)
- With age
- With pregnancy
When will overgrowth and infection if superficial candidosis occur? (2)
- When normal micro flora of the body is altered
- When resistance of infection is lowered by disease
What is another name for Acute pseudomembraneous candidosis?
Thrush
What groups of people are more likely to be affected by thrush? (3)
- New born
- Old/debilitated
- Medically compromised (HIV)
What is the clinical appearance of thrush?
What may occur if you try to remove these lesions?
- white plaques made of dead mucosal cells & hyphal elements
- Raw bleeding area forms
How does acute atrophic candidosis occur?
How does it clinically appear?
- Follows use of antibiotics which allows yeast overgrowth
- Tongue & cheek mucosa become thin & inflamed
What is chronic atrophic candidosis?
Red, swollen & inflamed mucosa under denture
Who are most at risk of chronic atrophic candidosis?
Affects 50-60% of denture wearers
What are some local predisposing factors of oral candidosis? (3)
- Trauma
- Occlusion
- Maceration
What are some salivary predisposing factors of oral candidosis? (4)
- Xerostomia
- Sjogren’s syndrome
- Radiotherapy
- Cytotoxic therapy
What is a dietary predisposing factors of oral candidosis?
High carbohydrate diet
What are some physiological predisposing factors of oral candidosis? (2)
- Infancy
- Old age
What hormonal states can be predisposing factors of oral candidosis? (4)
- Diabetes
- Hypothyroidism
- Hyperparathyroidism
- Hypoadrenocorticism
What are some nutritional predisposing factors of oral candidosis? (3)
- Hypovitaminosis
- Iron deficiency
- Malnutrition
What is vaginal candidosis?
White lesions on epithelium of vulva, vagina & cervix
What is a lab diagnosis test used to determine gram positive yeast cells?
Gram-stained smears of mucosal samples show budding Gram +ve yeast cells
How can you treat candida infections? (3)
Most superficial infections respond to topical therapy with
- Nystatin
- Amphotericin B
- An azole
Where may systemic candidosis occur? (5)
- Urinary tract
- Liver
- Heart valves
- Meninges
- Peritoneal cavity
Give some features of actinomyces (3)
- Gram positive
- Filamentous bacteria
- Facultative anaerobes
What is actinomycosis?
Chronic infection that causes;
- Multiple abscesses
- Granulomas
- Tissue destruction
- Extensive fibrosis
- Formation of sinuses
How do you test for actinomyces?
Crushed sulphur granules stained using Gram and modified Ziehl-Neelsen stains reveal Gram +ve mycelia and zone of acid-fast clubs
How do you treat actinomyces?
Penicillin or tetracycline often used
