Biofilm 3- Candida

Question 1

How big are yeast cells in comparison to bacteria?

Answer 1

25-50x.

Question 2

What us the physical scaffold called that fungi provide for bacteria?

Answer 2

Mycofilm.

Question 3

What are some risk factors for developing candidiasis?

Answer 3

Immuno-compromised patients
Immunosuppressive drugs
Advanced HIV infection
Intra-abdominal surgery
Central venous catheter
Parenteral nutrition
Broad-spectrum antibiotics
Dialysis
Colonisation at a sterile site
Diabetes
Burn unit patient
Trauma patient
Long-term corticosteroid use.

Question 4

What are the different types of infections from candidal disease?

Answer 4

Periodontitis
Dental implants
Denture stomatitis
CF lung infections
Ventilator associated pneumonia
UTI
Infectious kidney stones/biliary tract infections
Musculoskeletal infections/osteomyelitis
Chronic wounds
Sutures
Endocarditis
Implant/medical device
Catheters and stents.

Question 5

What are the two classifications of oral candidiasis and name some examples.

Answer 5

Confined to mouth and commissure (thrush, strophic, denture related and candidal leukoplakia)

Generalised candidasis with oral manifestations (chronic mucocutaneous).

Question 6

What does pseudomembraneous candidasis appear like in the mouth?

Answer 6

White plaques on the surface of mucosa but when you scrape them away they will bleed.

Question 7

Do you need to take a biopsy of chronic hyperplastic mucosa?

Answer 7

Yes.

Question 8

What is angular chelitis, what type of bacteria causes it and what topical antifungal is most commonly used?

Answer 8

Angular cheilitis (AC) is inflammation of one or both corners of the mouth. Often the corners are red with skin breakdown and crusting. It can also be itchy or painful. The condition can last for days to years.
Angular cheilitis is a type of cheilitis (inflammation of the lips).
Candida
Gram positive bacteria that interact
Miconazole topical most used.

Question 9

What do the different classes of Newton’s types for denture induced stomatitis mean?

Answer 9

1- localised inflammation
2- diffuse inflammation
3- granular inflammation.

Question 10

What are some signs and symptoms of denture induced stomatitis?

Answer 10

Inflamed mucosa- particular under upper denture
Burning sensation
Discomfort
Bad taste
In most cases- the patient is unaware of the problem!

Question 11

What is denture induced stomatitis?

Answer 11

Denture stomatitis is caused by a yeast or fungus called candida. It is not an infection that we get or pass on to others, because we all have some candida in our mouths. Thrush can appear in other parts of the body, but when it affects the mouth it may be called ‘denture stomatitis’.

Question 12

What can denture induced stomatitis cause if the bacterial particles are inhaled?

Answer 12

Aspiration pneumonia.

Question 13

What happens to the denture and the mucosa in denture induced stomatitis?

Answer 13

Trauma for changes in typography of PMMA
Toxins
Mucosal thinning
Inflammation
Exudate and squames.

Question 14

What are some opportunistic pathogenic yeasts?

Answer 14

Candida albicans
Candida glabrata
Candida tropicalis etc.

Question 15

What is the changing epidemiology of candida spp. in Scotland between 2005/06 and 2012-13?

Answer 15

More candida glabrata and less candida albicans.

Question 16

What is candida albicans?

Answer 16

Present in 71% of healthy individuals
-oral carriage varies (35-55%)

Variable anatomical sites
-oral cavity, vagina, gut (mucosal surfaces)

Nutrient limitation/competition with bacteria.

35% mortality rate.

Question 17

How does candida albicans get into the blood stream?

Answer 17

When candida albicans is stressed it can go to this hyphae- can invade through tissue- can get into blood stream- issues
Gibrata doesn’t from these hyphae
1. Adhesion and colonisation
2. Hyphal penetration and invasion
3. Vascular dissemination
4. Endothelial colonisation and penetration.

Question 18

What is a hydrolytic enzyme?

Answer 18

An enzyme that catalyses the hydrolysis of a substate through the addition of water.

Question 19

What is phospholipase, haemolysin and proteinase’s substrate and contribution to infection?

Answer 19

P- lipid, host cell penetration
H- red blood cells, facilitates hyphal invasion
P- proteins, adhesion to epithelial cells.

Question 20

What candida related infection do some individuals in Finland possess that makes them more likely to develop oral cancer?

Answer 20

APECED.

Question 21

What do you need to be careful as a clinican when prescribing for a candida infection?

Answer 21

Generally candida albicans are sensitive to fluconazole nitroconazole (unsure whether this is right or it should be myconazole)

Whereas canida glabrata is not

The key issue is that as a clinician you will generally want to treat the patient you want to give them anti-fungals but needs to consider if the patient has candida glabrata (which is more common than you would think) then all you are doing is suppressing everything else and letting candida glabrata grow.

Question 22

What is Sabouraud agar used for?

Answer 22

Sabouraud agar or Sabouraud dextrose agar (SDA) is a type of agar growth medium containing peptones. It is used to cultivate dermatophytes and other types of fungi, and can also grow filamentous bacteria such as Nocardia. It has utility for research and clinical care. ONLY TELLS US IF WE HAVE CANDIDA NOT WHAT SPECIES IT IS.

Question 23

Why is chromogenic agar good?

Answer 23

Has different colours for different colonies- lets us know if specific organisms are present.

Question 24

What does chitin do?

Answer 24

Strengthens the cell wall.

Question 25

What do azoles directly work upon?

Answer 25

They work indirectly on the ergesterol synthesis pathways (it is fungistatic)
Fluconazole, voriconazle and posaconazole.

Question 26

How do polenes work and name some examples.

Answer 26

They work directly on ergesterol and bind to it which causes pores (it is fungicidal)
Nystatin, Amophotericin B and Liposomal AmB.

Question 27

How do echinocandins work and name some examples.

Answer 27

They act on 13 beta glucan synthase synthesis and destabilise the cell wall- they are good against biofilms
Caspofungin, micafungin and anidulafungin.

Question 28

What is the activity of fluconazole?

*there is a table on this slide with lots of different drug activities but this one is highlighted in red.

Answer 28

C. albicans generally sensitive but resistant strains can develop
C. krusei and C. glabrata naturally resistant.

Question 29

What increases in the individual when they are repeatedly given an increased dose of fluconazole?

Answer 29

Relapsed in oral pharyngeal candidiasis
100mg per day for 9 visits then upped
Sample taken
Over these visits you see an increase in these multi 
drug resistant pumps
Changes in ergosterol biosynthesis genes
Massive increase in CDR pumps
Inappropriate treatment
Changes in genetics of organism.

Question 30

What different factors drive the inability to treat candida infections?

Answer 30

Density
Stress
Persisters
ECM
Efflux
Over expressed targets
Physiology.

Question 31

What is a dual-resistance mechanism?

Answer 31

Candida can live among things like staph aureus

Staph aureus can actually coat itself in candida polymers and can become resistant to vancomycin

Gene resistance when bacteria and candida live together

Mixed species biofilms can increase the resistance.

Question 32

What are azoles ineffective against?

Answer 32

Biofilms.

Question 33

Is chlorhexidine used to treat fungal infections?

Answer 33

Yes.