Microbiology Flashcards
What is being described?
- found in the canals of teeth
- very difficult to destroy
- infect nerve cells: transmissible spongiform encephalopathy, Creuzfeld Jakob disease
- no DNA or RNA
- promotes refolding of native proteins
prions
What are 5 oral factors that affect oral microbiology?
- anatomy - alignment of teeth
- saliva
- gingival crevicular fluid
- microbial factors
- local environment
(moisture, pH, antimicrobial therapy, diet, fluoride)
Which bacteria can be found in deep perio pocketing?
porphyromonas
Which bacteria is the following?
Gram-negative, facultative anaerobe, nonmotile bacterium that is often found in association with localized aggressive periodontitis, a severe infection of the periodontium. It is also suspected to be involved in chronic periodontitis.
aggregatibacter
Which fungi bacteria is especially associated with dentures and is a yeast bacteria?
Candida albicans
Which fungi bacteria is the following?
- only tend to cause problems for immunocompromised patients
filamentous and dimorphic fungi
What are 4 examples of how to get oral specimens?
- aspirate of pus for purulent infection
- deep gingival smear for ANUG
- rise for quantifying oral candida
- paper point samples for periodontal pockets for molecular identification (gene probing using PCR)
What are 3 methods of lab analysis?
- non-cultural methods (microscopy, gene probing)
- cultural methods (cultured cells to grown viruses)
- immunological methods (identify organisms using antibodies)
Why is microbiological sampling not commonly used in dentistry?
- hard to avoid contamination of samples in oral specimens
- infections need to be treated quickly to avoid infection getting worse so therefore cannot wait for results to return
- can be hard for patient with facial swelling to tolerate rubber dam
When should oral microbiological culture be taken?
if antimicrobial resistant infection is suspected
or
sometimes before prescribing co-amoxiclav or clindamycin
What are the 2 methods of susceptibility testing?
- minimum inhibitory concentrations (MIC)
- minimum bactericidal concentration (MBC)
What is the benefit of being able to interpret microbiology report?
evidence to help weight up the risks and benefits of treatment options
Which bacteria is the following?
- thought to be involved with initiation
- responsible for causing caries
- gram positive cocci
- crystal violet entrapped in thick peptidoglycan cell wall
- safranin pink not visible
streptococcus mutans
Which bacteria are the following?
- pioneer organism in advancing form of caries
- thought to be involved with deeper lesions
- some of this bacteria has been associated with cases of dental caries (cavities). Lactic acid can corrode teeth, and the Lactobacillus count in saliva has been used as a “caries test” for many years. Lactobacilli characteristically cause existing carious lesions to progress, especially those in coronal caries
lactobacillus spp
Which bacteria is the following?
- found in plaque
- associated with root caries
- a colonial bacterium which can be found as a commensal in the mouth and tonsillar crypts
actinomyces israelii
Which bacteria is the following?
- found in the bottom of periodontal pockets
- Gram-negative, facultative anaerobe, nonmotile bacterium that is often found in association with localized aggressive periodontitis, a severe infection of the periodontium. It is also suspected to be involved in chronic periodontitis
aggregatibacter actinomycetemcomitans
Which bacteria is the following?
- Gram-negative, rod-shaped, anaerobic, pathogenic bacterium
- it is found in the oral cavity, where it is implicated in periodontal disease
porphyromonas gingivalis
Which bacteria is the following?
- the word planktonic is widely used in microbiology for organisms that are floating in bodies of water
- a Gram-positive round-shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin
staphylococcus aureus - planktonic
What is being described?
- a complex structure adhering to surfaces that are regularly in contact with water, consisting of colonies of bacteria that secrete a mucilaginous protective coating in which they are encased
- examples: inside of fish tank, sink U bend, dental plaque, dental unit water lines
biofilms
How is supra gingival oral biofilm disrupted?
tooth brushing
How is sub gingival oral biofilm disrupted?
ultrasonic debridement
What are the 5 stages of biofilm formation?
- initial attachment
- irreversible attachment
- maturation I
- maturation II
- dispersion
What percentage of dental plaque is made up of organic components?
30%
Which tooth surfaces are more protected from host defences and cleaning?
- occlusal fissures
- contact points
- buccal and palatal smooth surfaces
Which patients are more likely to form plaque more quickly?
- those with reduced salivary flow
- reduced muscular movements
- desquamation - lower rate
What are the 4 stages of biofilm formation?
- pellicle formation
- early colonisers
- late colonisers
- detachment
Which stage of oral biofilm formation is the following?
- selective binding of salivary glycoproteins to tooth surface
- within minutes of cleaning - protects teeth from acids
pellicle formation
Which stage of oral biofilm formation is the following?
- eg. streptococcus spp
- net adhesion - balance of van Der Waals forces and electrostatic repulsion
- irreversible adhesion - polymer bridging between organisms and pellicle
- link to caries
early colonisers
Which stage of oral biofilm formation is the following?
- eg. actinomyces israelii, P. gingivalis
- coaggregation - new bacteria attach to early colonisers
- complexity of biofilm increases with time - climax community
- link to periodontal pathogens
late colonisers
Which stage of oral biofilm formation is the following?
- bacteria can become planktonic and spread to new sites
detachment
What 2 components make up extracellular matrix?
- salivary glycoproteins
- microbial polysaccharides
Which 2 bacterias form lactic acid bacteria?
streptococci spp
and
lactobacilli spp
What is the main source of nutrients for oral bacteria?
saliva
The following bacteria are associated with what?
- mainly gram positive cocci
- streptococcus sanguis
- streptococcus oralis
- actinomyces naeslundi
- actinomyces viscous
- veillonella spp (gram negative anaerobic cocci)
periodontal health
What are the 3 phases of plaque-associated gingivitis?
- initial lesion - develops within 4 days of plaque accumulation
- early lesion - within 7 days
- established lesion - continuation
Which phase of plaque induced gingivitis is the following?
- acute inflammatory reaction > vasculitis, perivascular collagen destruction, increase in crevicular fluid and PMN leucocytosis in the junctional epithelium and crevice
initial lesion
Which phase of plaque induced gingivitis is the following?
- dense infiltration of lymphocytes (75%) with macrophages and plasma cells
- areas of local collagen destruction
- polymorph infiltration of sulcus - peaks 7-12 days
early lesion
Which phase of plaque induced gingivitis is the following?
- changes in the gingival crevice support predominantly anaerobic flora
- to reverse the disease, need to clean in the deepest part of the crevice
established lesion
The following bacteria are mainly associated with what?
- 55% gram positive with occasional spirochaetes and motile rods
- Streptococcus sanguinis
- Streptococcus milleri
- Actinomyces israelii
- Actinomyces naeslundi
- Capnocytophaga spp
- Fusobacterium nucleatum
- Veillonella spp
gingivitis
The following bacteria are mainly associated with what?
- ~75% Gram negative of which 90% anaerobic. Motile rods and spirochaetes
- Porphyromonas gingivalis
- Prevotella intermedia
- Fusobacterium nucleatum
- Tannerella forsythia
- Aggregatibacter actinomycetemcomitans
- Selenomonas spp
- Capnocytophaga spp
- Spirochaetes
- Viruses may be linked but no conclusive data
chronic periodontitis
The pathogenesis of which disease is the following?
- sub gingival plaque spreads apically
- junction epithelium separates from the tooth surface
- inflammatory tissue reactions results in destruction of gingival connective tissue and alveolar bone
chronic periodontitis
The following bacteria are mainly associated with what?
- 65-70% Gram-negative bacilli. Few spirochaetes or motile rods.
- Aggregatibacter actinomycetemcomitans
- Capnocytophaga spp
- Porphyromonas gingivalis
- Prevotella intermedia
- May be associated with cellular immunity or genetic defects
aggressive periodontitis
Which oral disease is the following?
- acutely inflamed, red, shiny and bleeding gingivae
- irregularly shaped ulcers on the interdental papillae
- painful condition - pseudomembranous slough - offensive smell
- linked to poor OH, stress, smoking, malnutrition, immunosuppression
- anaerobic, polymicrobial infection
- fusobacterium nucleatum
- spirochaetes
necrotising ulcerative gingivitis
Which condition is the following?
- a rapidly and frequently fatal progressive gangrenous cellulitis and oedema of the soft tissues of the neck and floor of the mouth. It originates in the region of the submandibular gland with elevation and displacement of the tongue
- bacteria from dental infections or poor oral hygiene are the cause of this skin infection
- can develop if you get a cavity or tooth abscess – often in your second and third molars – or you get periodontitis or gingivitis.
Ludwig’s angina
Which bacterial infection of the mouth is the following?
- salivary gland infections - may be bacterial or viral
sialadenitis
Which bacterial infection of the mouth is the following?
- treponema pallidum
- transmission via direct contact with lesions
- Hutchinson’s incisors/mulberry molars
syphilis
Which bacterial infection of the mouth is the following?
- granulomatous disease from mycobacterium tuberculosis
tuberculosis
Which bacterial infection of the mouth is the following?
- mycobacterium leprae
- atrophy of the anterior nasal spine, saddle nose
leprosy
Which oral fungal infections are the following?
- pseudomembranous - wipes off
- erythematous
- hyperplastic
oral candidiasis
Which oral fungal infections are the following?
- denture stomatitis
- angular cheilitis
- median rhomboid glossitis
candida-associated infections
Which bacteria is responsible for >90% of human candida infections?
Candida albicans
What are 5 predisposing factors for candida infections?
- ill fitting or poor hygiene of oral appliance
- disturbed oral ecology eg. xerostomia or antibiotic therapy
- immunological or endocrine disorder eg diabetes
- malignant or chronic disease
- heavy smoking
What are the following?
- HHV1; primary infection - herpetic gingivostomatitis
secondary - herpes labialis (cold sore)
- HHV2 (genital infections)
- HHV3; Varicella zoster primary infection - chicken pox, secondary infection - shingles
- HHV4; epstein-barr virus, infective mononucleosis (glandular fever), hairy leukoplakia (associated with HIV)
- HHV8; Kaposis sarcoma (associated with HIV)
herpes viruses
What illnesses are associated with coxsackieviruses (group A) - papulovesicular lesions?
- hand, foot and mouth disease
- herpangina
What illness is associated with paramyxovirus?
mumps - enlargement of one or more parotid glands
What are 6 oral manifestations of HIV?
- xerostomia
- enlargement of major salivary glands
- candidiasis
- hairy leukoplakia
- kaposis sarcoma
- necrotising periodontitis
What does bactericidal mean?
kills bacteria
What does bacteriostatic mean?
keeps bacteria in the stationary phase of growth