Microbiology - Candida Flashcards
how does candida and bacteria interact?
creates a mycofilm (scaffold) for the bacteria
describe how candida and bacteria can cause dual resistance.
staph aureus (bacteria) coating itself with candida polymers
what are the main opportunistic pathogenic candida?(2)
Candida albicans
Candida glabrata
what candida is sensitive to fluconazole?
albicans
what candida is resistant to fluconazole and what is the problem associated with this?
C. glabrata not sensitive
if u give a patient with this fungi an ‘azole’ medication you are just suppressing everything else and allowing the glabrata to thrive.
what species of candidia have hyphae? (1)
albicans
describe how c.albicans causes candidiasis. (5)
- penetrates with hyphae
- Starts to form germ tubes
- Produces an extracellular matrix and Creates a biofilm – adheres, hard to penetrate and remove from surfaces
- They produce hydrolytic enzymes within the biofilm – phospholipase, haemolysin, proteinase (allows it to move through tissue)
- Causes system candidiasis
what are the limitations of antifungals? (3)
- Limited variety available
- Some are toxic
- There is resistance
name causes of fungal infections? (3)
- Immunosuppression
- Broad-spectrum antibiotics - bacteria are suppressed which allow the fungi to thrive
- Use of steroids
list the main types of candidiasis found in the mouth. (4)
- Pseudomembranous = thrush
- Erythematous = denture or HIV related
- Hyperplastic = candida leucoplakia (premalignant)
- Angular cheilitis
what candidal infection requires biopsy?
Chronic hyperplastic: candida leucoplakia
how is erythematosis candidiasis classified?
Newtons typing
describe the levels of newtons typing.
Newtons type I = localised inflam
NT II = diffuse inflam
NT III = widespread granular inflam
what types of candidosis occurs in conjunction with bacteria? (2)
Angular cheilitis
Erythematous
what are the symptoms of candidosis? (4)
- Inflamed mucosa
- Burning
- Discomfort
- Bad taste
how do we diagnose different types of candidosis?
pseudomembranous, localised and leukoplakia.
• For pseudomembranous candidiasis you can scrape it off and put it on a slide – if you see hyphae you know its albicans and you can use azoles.
- Standard procedure is to then give the patient an oral rinse
- If there is localised inflammation– use a swap this is standard practice
- Leukoplakia = take a biopsy and look at it histologically
what agar dish is best to use and why?
Best to place the swab on a chromogenic agar plate as it shows you the specific organisms present by using different colours.
what autoimmune disease causes people in their early 20’s to develop oral cancer?
APECED
where is the autoimmune disease APECED found?
found in bottleneck countries such as Finland
how do the ‘azole’ antifungals work? (3)
- Fungistatic
- work on ergosterol biosynthesis pathways.
- Ineffective against biofilms
name an example of a polyene antifungal?
nystatin
how do polyene antifungals such as nystatin work?
- Fungicidal
- act directly on the ergosterol by binding and cause pores = leaking of the cytoplasmic contents
what should we use before prescribing antifungals?
Use chlorhexidine
What happens if antifungals (azoles) are used inappropriately? (3)
- Overexpression of molecules within the ergosterol biosynthesis pathways.
- Overexpression of candida drug resistant pumps
- Overexpression of multi drug resistant pumps
name the virulence factors of candida (2)
hyphae for penetration
produces ECM
ECM:
dense = no penetration
produces polysaccharides and glucans
name the features of an ECM that makes them resistant? (2)
dense - hard to penetrate
contains polysaccharides and glucans
what anti fungal is safe to use in patients on warfarin?
nystatin
