M9: Candida, Other fungi & Actinomyces

Question 1

What are the 2 main groups of fungi?

Answer 1

• Moulds

- Yeast

Question 2

Fungi can have 3 different characteristics, what are they?

Answer 2

• Saprophytes (in soil/decaying plant material)
• Parasites
• Commensals (no harm)

Question 3

Give some features of moulds (2)

Answer 3

• Mycelial fungi
• Branching filaments which form interwoven mass
• Reproduce by means of spores

Question 4

Give some features of yeasts (2)

Answer 4

• Predominately unicellular

- Reproduce by budding

Question 5

What are dimorphic fungi?

Answer 5

Either mycelial or yeast phase depending on growth conditions

Question 6

What does form and severity of a fungal disease depend on? (4)

Answer 6

• Degree of exposure
• Site of exposure
• Method of entry into body
• Level of immunocompetence of host

Question 7

What are the 3 types of fungal infection?

Answer 7

• Superficial mycoses
• Subcutaneous mycoses
• Systemic mycoses

Question 8

What does mycoses mean?

Answer 8

A disease caused by a fungus

Question 9

Where can superficial mycoses occur? (4)

Answer 9

• Skin
• Hair
• Nail
• Mucous membranes

Question 10

What is the most common type of fungal infection?

Answer 10

Superficial mycoses

Question 11

What is ringworm?

Answer 11

A complex of disease caused by moulds

Question 12

What are Dermatophytes?

Answer 12

• Fungi that affect keratinous tissues of hair, nail & skin
• As they can colonise and digest keratin

Question 13

Where can subcutaneous mycoses occur? (3)

Answer 13

• Skin
• Subcutaneous tissues
• Bone

Question 14

How doe systemic mycoses occur?

Answer 14

Generally result from inhalation of airborne mould spores

Question 15

80-90% of superficial mycoses is caused by what?

Answer 15

C.albicans

Question 16

Generally why do fungal infections arise?

Answer 16

Infection often arises due to deficiencies in the host rather than because of any inherent pathogenic properties of the fungus

Question 17

How are fungal infections diagnosed?

Answer 17

Combination of clinical observation & lab investigation

Question 18

How do ringworm infections spread? (2)

Answer 18

• Direct contact

- Indirect contact

Question 19

What are some clinical presentations of ringworm infections? (4)

Answer 19

• Irritation
• Erythema
• Oedema
• Vesiculation

Question 20

When does carriage of superficial candidosis increase? (2)

Answer 20

• With age

- With pregnancy

Question 21

When will overgrowth and infection if superficial candidosis occur? (2)

Answer 21

• When normal micro flora of the body is altered

- When resistance of infection is lowered by disease

Question 22

What is another name for Acute pseudomembraneous candidosis?

Answer 22

Thrush

Question 23

What groups of people are more likely to be affected by thrush? (3)

Answer 23

• New born
• Old/debilitated
• Medically compromised (HIV)

Question 24

What is the clinical appearance of thrush?

What may occur if you try to remove these lesions?

Answer 24

• white plaques made of dead mucosal cells & hyphal elements
• Raw bleeding area forms

Question 25

How does acute atrophic candidosis occur?

How does it clinically appear?

Answer 25

• Follows use of antibiotics which allows yeast overgrowth

- Tongue & cheek mucosa become thin & inflamed

Question 26

What is chronic atrophic candidosis?

Answer 26

Red, swollen & inflamed mucosa under denture

Question 27

Who are most at risk of chronic atrophic candidosis?

Answer 27

Affects 50-60% of denture wearers

Question 28

What are some local predisposing factors of oral candidosis? (3)

Answer 28

• Trauma
• Occlusion
• Maceration

Question 29

What are some salivary predisposing factors of oral candidosis? (4)

Answer 29

• Xerostomia
• Sjogren’s syndrome
• Radiotherapy
• Cytotoxic therapy

Question 30

What is a dietary predisposing factors of oral candidosis?

Answer 30

High carbohydrate diet

Question 31

What are some physiological predisposing factors of oral candidosis? (2)

Answer 31

• Infancy

- Old age

Question 32

What hormonal states can be predisposing factors of oral candidosis? (4)

Answer 32

• Diabetes
• Hypothyroidism
• Hyperparathyroidism
• Hypoadrenocorticism

Question 33

What are some nutritional predisposing factors of oral candidosis? (3)

Answer 33

• Hypovitaminosis
• Iron deficiency
• Malnutrition

Question 34

What is vaginal candidosis?

Answer 34

White lesions on epithelium of vulva, vagina & cervix

Question 35

What is a lab diagnosis test used to determine gram positive yeast cells?

Answer 35

Gram-stained smears of mucosal samples show budding Gram +ve yeast cells

Question 36

How can you treat candida infections? (3)

Answer 36

Most superficial infections respond to topical therapy with

• Nystatin
• Amphotericin B
• An azole

Question 37

Where may systemic candidosis occur? (5)

Answer 37

• Urinary tract
• Liver
• Heart valves
• Meninges
• Peritoneal cavity

Question 38

Give some features of actinomyces (3)

Answer 38

• Gram positive
• Filamentous bacteria
• Facultative anaerobes

Question 39

What is actinomycosis?

Answer 39

Chronic infection that causes;

• Multiple abscesses
• Granulomas
• Tissue destruction
• Extensive fibrosis
• Formation of sinuses

Question 40

How do you test for actinomyces?

Answer 40

Crushed sulphur granules stained using Gram and modified Ziehl-Neelsen stains reveal Gram +ve mycelia and zone of acid-fast clubs

Question 41

How do you treat actinomyces?

Answer 41

Penicillin or tetracycline often used