caries microbiology Flashcards
what type of bacteria cause endodontal infections
endogenous bacteria (bacteria already within body)
give 2 examples of endodontic infection pathogens
porphyromonas endodontalis
enterococcus faecalis
what is the oral microflora influenced by
host factors - systemic disease, antibiotic use, genetics
Diet - frequency of intake, chemical composition
Saliva - flow rate, pH
GCF - antimicrobial components
Microbial interactions - competition and co operation
describe the microbiological process of periodontal disease
initial adhesion
colonisation
accumulation
complex community formation (disease causing)
dispersal (disease spreading)
what are 2 important microorganisms in gingival health
veillonella
actinomyces
name 2 microorganisms assosciated with gingivitis
actinomyces
prevotella intermedia
name 3 microorganisms assosciated with periodontal disease
prevotella intermedia
porphyromonas gingivalis
tanerella forsythia
microbial interactions
- competition vs co operation
competition - production of bacteriocins (kill other bacteria), metabolic products create environment for their species to thrive
co operation - work together for immune avoidance
name 3 virulence factors of porphyromonas gingivalis
fimbriae: long aid attachment to host cells and short aid cell to cell autoaggregation
Gingipains: proteases which downregulates host immune response, activate MMPs and degrade host proteins to use as an energy source
atypical endotoxins - block host signalling via TLR - 4s
Biofilm formation: allows initiation of tissue destruction
name 3 systemic conditions periodontal disease has been linked with
diabetes
rheumatoid arthritis
cadriovascular disease
mycofilm
fungi providing scaffolding for bacteria to attach
e.g candida albicans and s.mucans
name 4 risk factors for candia infection
(all centre around immunosuppresion)
- advanced HIV
- immunosuppresive drugs
- immunocompromised patients
- dialysis patients
- diabetes patients
- long term corticosteroid use
- broad spectrum antibiotics
what are the 4 main types of oral candidosis
- pseudomembranous (thrush)
- erythmatous
- hyperplastic
- angular chellitis
pseudomembranous oral candidosis appearance
white pronounced plaques that can be easily rubbed away but might leave a bleeding surface
erythmatous candida appearance
red and angry looking
newtons classification
scores denture stomatitis from I to III from least to most severe
Denture stomatitis
common fungal infection
candida adhere and colonise acrylic fitting surface of denture and if not cleaned regularly this colony can grow and lead to candida infection
what is the biggest risk if denture stomatitis infection is allowed to grow and persist
aspiration pneumonia
signs and symptoms of denture stomatitis
inflamed mucosa under denture
burning sensation
discomfort
bad taste
- many patients will be unaware
hyperplastic oral candidosis
assosciated with candidal leukoplakia and can be pre malignant
less pronounced and less plaque like than pseudomembranous, cant be scraped off
biopsy is required
what is the key topical antifungal for treating angular chellitis
miconazole
what are the 2 subtypes of candida most often found in the oral cavity
candida albicans
candida glabrata
what antifungal should be given if candida infection caused by candida albicans
fluconazole
itraconazole
what antifungal should be given if candida infection caused by candida glabrata
nystatin
what structure does candida albicans have that candida glabrata does not which aids its pathogenicity
albicans can stretch to form long tail like hypha which can squeeze into small areas and aid invasion of tissues
what is the link between chronic candida infection and oral cancer
if yeasts (candida) are given simple sugars they can metabolise these to alcohol
alcohol itself does not cause cancer instead its the acetaldehyde produced from alcohol breakdown that acts as a carcinogen and has the potential to cause DNA damage
smear
scrape and view under microscope
e.g of pseudomembranous candidosis
oral rinse
ask patient to swirl saline solution then grow on agar
e.g denture stomatitis
swab
cotton swab to affected area of mucosa then grow on agar
(good for children as easy and quick)
biopsy
small sample taken so histology can be analysed
what type of agar can distinguish between candida species
chromogenic agar
What are the 3 main components of fungal cell walls
chitin
mannoproteins
glucan
azole antifungals
inhibit ergosterol synthesis which is present in fungal cell membranes
e.g fluconazole
mitraconazole
polyene antifungals
bind directly with ergesterol on cell membrane and cause pores to open up. This sees leakage of cytoplasmic membrane and cell death
e.g nystatin
what is a good first line option for treating oral candida infections
chlorhexidine mouthwash
antifungal and antibacterial
echinocandin antifungals
inhibit enzyme that is vital for cell wall formation - results in cell death
e.g caspofungin
