Candida infections Flashcards

1
Q

Where are the candida species found?

A

Common in the oral cavity, GIT and vagina as a commensal

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2
Q

Describe the shape of candida

A

Polymorphic fungus - it takes up many shapes

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3
Q

What is the importance of candida?

A

It is the most common fungal pathogen in humans, and the most medically important fungus

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4
Q

Describe the pathogenicity of candida

A

It is a harmless commensal and opportunistic mycoses, which develops mucosal infections in certain conditions e.g. immunocompromised

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5
Q

What species of candida is most important?

A

Candida albicans

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6
Q

What are the stages of candida albicans infections?

A
Colonisation 
Superficial infection 
Deep spread infection 
Disseminated infections 
(Host and fungal factors play a role in the development from superficial to deep seated infections)
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7
Q

List the predisposing factors for oral candidal infections

A
  • Immunocompromised - diabetes, HIV/AIDs, cancer or chemo, organ transplants
  • Drugs causing antimicrobial change to flora e.g. antibiotics
  • Diet/nutrition - iron, folate or vit b12
  • Mechanical and chemical - burns, wounds, smoking and dentures
  • Xerostomia - medications, sjogrens
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8
Q

What cells are important for colonisation of candida?

A

Adhesion factors to anchor bacteria to epithelial walls
Enzymes to interact with cell membrane
Hyphae formation for adhesion

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9
Q

What are the adhesion factors in candida?

A

Agglutin like sequence 3

Hyphal wall protein 1

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10
Q

What type of bonding occurs between candida and epithelial walls

A

Covalent - therefore v strong

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11
Q

What enzymes are important in candida infections

A

SAPs - secreted aspartyl proteinases
Lipases
Phosphilipase Bs

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12
Q

How does superficial candida infection arise?

A

Penetration and anchoring of hyphae, causing degredation of epithelium via toxin production (candidalysin)

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13
Q

What is candidalysin?

A

Antimicrobial peptide (toxin) that integrates into the membrane and damages epithelial cells

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14
Q

Why is pain and itching associated with candida infections?

A

Due to toxin production

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15
Q

What occurs with disseminated candida infections?

A

Penetration through epi to major organs which can be fatal

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16
Q

How does the body attempt to clear candida infection?

A

Secretion of proinflammatory mediators to recruit neutrophils (direct killing) and dendritic cells (APC to th17 cells)
These secrete cytokines to kill fungi or repair epithelium

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17
Q

What cytokines are vital in candida infections?

A

TNFa

IL22 and IL17

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18
Q

What is the classification of oral candida infections

A
Acute 
- Pseudomembranous 
- Atrophic candidiasis 
Chronic 
- Hyperplastic 
- Atrophic 
Others 
- Erythematous 
- Angular chelitis
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19
Q

Describe the clinical features of: pseudomembranous candida

A

White patches which are easily removed on scraping

Associated with extremes of age

20
Q

Describe the clinical features of: atrophic candidiasis

A

Depapillation of tongue - smooth and red

Associated with antibiotics

21
Q

Describe the clinical features of: chronic hyperplastic candida

A

White or a mix of red and white patches
Looks like pseudomembranous but you cannot remove the plaque
Sites- BM adjacent to commissures

22
Q

What is chronic hyperplastic candida associated with

23
Q

What is the important features of chronic hyperplastic candida

A
  • Fungus is inside the epithelial cells

- Persistent lesions show epithelial dysplasia - considered OPML

24
Q

Describe the clinical features of: chronic hyperplastic candida associated with median rhomboid glossitis

A

Back and middle of the tongue

Glossy appearance

25
Describe the clinical features of: Chronic atrophic candida (denture related stomatitis)
Erythema of mucosa associated with area covered by (upper) denture Angular stomatitis is associated
26
Describe the clinical features of: erythematous candida
Erythema and smoothness of the middle of the dorsal tongue Redness of palate corresponding to tongue Longer lesion than MRG
27
What is chronic erythematous candida associated with
Denture wearing
28
Describe the clinical features of: angular cheilitis/stomatitis
Soreness, erythema and fissuring of the commissures (corners of the mouth)
29
What causes angular cheilitis
Leakage of candida infected saliva at the commissures
30
Risk factors for angular cheilitis
Deep folds due to age Ill fitting dentures Nutritional deficiencies
31
Describe the steps for the management of candida
- Establish diagnosis - clinical features and special tests - Remove, reduce or manage risk factors - Antifungal agents
32
What is CHROMagar
Special testing for candida to identify the strain (they appear as different colours)
33
What are the types of tests for candida?
Smear Swab Saliva Biopsy
34
What mechanisms can antifungals affect
- Nucleic acid biosynthesis - Ergosterol biosynthesis - Membrane function - Cell wall biosynthesis
35
How do Azoles work?
Prevent biosynthesis of ergosterol
36
How does Nystatin work?
Punch holes in the plasma membrane, resulting in lysis of the cell
37
What anti-fungals are involved in preventing cell wall biosynthesis
Echinocandins | Caspofungins
38
How do caspofungins work?
Prevent beta glucan synthesis which makes the cell walls - causes the candida to burst
39
What are the most commonly used antifungals in dentistry?
Nyastatin Fluconazole Miconazole Intraconazole
40
What types of therapy is used for candida
Topical | Systemic
41
Describe topical antifungal therapy
Nyastatin in the form os lozenges and suspension | Miconazole gel for lips, tongue and denture fitting surfaces
42
How can dentures be treated if affected by candida
Placed overnight in: Sodium hypochlorite CHX
43
When are systemic antifungals considered
If local therapy doesn't work | Or it is severe
44
Prophylaxis of candida
- CHX mouthwash daily if uncontrollable risk factors | - Rinsing mouth after using steroid inhalers
45
When should azoles be avoided
In pts taking NOACs/warfarin | Instead - nyastatin