Oral Microbiology

Oral Bacterial Ecology

What are the major species of Viridans Streptococci?

- S. mitis

- S. mutans

- S. salivarius

- S. sanguis

- S. parasanguis

TRUE or FALSE

Viridans species are sensitive to optochin

FALSE

TRUE or FALSE

All Viridans species are alpha hemolytic

FALSE

Answer: Alpha or gamma

TRUE or FALSE

S. pneumoniae is part of the Viridans species

FALSE

What two clinically important phenomena are associated with Viridans Streptococci?

Dental caries and infective endocarditis

What species causes dental caries?

S. mutans

What enzyme is used to metabolize sucrose into glucan polymers?

Glucosyl transferase

Sucrose is metabolized into sticky _____ polymers

glucan

What increases binding of S. mutans and other species to the tooth surface forming plague?

Glucan polymer

What results from the metabolism of sugars to lactic acid which demineralizes the tooth enamel?

Cavity formation

Infective endocarditis colonize on?

Damaged heart valve

What can lead to endocarditis?

Tooth extraction

What is the etiological agents of caries?

S. mutans

Stephan curve

What is the pH at which decalcification of enamel occurs?

5.5

What contains microbial cells that are encased by a matrix?

Bioflim

What is the extracellular matrix of biofilm composed of?

Microbial polymers and salivary glycoproteins

Biofilm protect bacteria from?

Anti-bacterial and host immune mechanisms

Biofilm allows the development of antibacterial resistant. This is due to inactivation or lower drug activity in the biofilm _____ _____

micro environment

What is the absorption of host/bacterial molecules on the surface of the tooth?

Pellicle formation

What is a protective species due to it metabolism of lactate?

Veillonella

What species is associated with periodontitis, endocarditis, and bite wound infections?

Actinobacillus actinomycetemcomitans

What are fungus-like bacteria?

Actinomyces species

Actinomyces sp. and Nocardia sp. are gram-_____ bacteria

positive

What is the etiological agent of actinomycosis?

Actinomyces sp.

What is the etiological agent of nocardiosis?

Nocardia sp.

TRUE or FALSE

Actinomyces sp. are aerobic

FALSE

TRUE or FALSE

Nocardia sp. are catalase positive

TRUE

What are gram positive rods that causes endogenous infection associated with trauma or poor hygiene?

Actinomyces species

What species are isolated from human plaque, calculus, tonsillar crypts and are associated with most cases of human actinomycosis?

A. israelii

What species preferentially colonizes tongue and other mucosal surfaces?

A. naeslundii

What species preferentially colonize teeth?

A. viscosus

What disease occurs when the normal mucosal barriers are disrupted?

Actinomycosis

Actinomycosis is characterized by?

Painful abscesses, draining sinus tracts, an sulfur granules

What species has a molar tooth appearance?

A. israelii

What disease is characterized by the following?

- Bronchopulmonary

- Mycetoma

- Lymphocutaneous

- Cellulitis and subcutaneous abscesses

- Brain abscess

Nocardiosis

What is often seen in the hard and soft palate in patients with HIV? It is described as white plaques that can be wiped off/

Pseudomembranous candidiasis

What are lesions on the soft and hard palate that cannot be wiped off and do not respond well to topical antifungal?

Hyperplastic (chornic) candidiasis

Hyperplastic candidiasis are seen in patients with?

Low CD4 cells count and diminished salivary flow

Porphyromonas gingivalis are human associated _____ bacteria

black-pigmenting

Biofilm are made up of _____

dextran

TRUE or FALSE

There are more anaerobic bacteria found in the subgingival of person with periodontitis

TRUE

What species are gram-negative coccus and spirochete?

Veillonella and Treponema denticola

Black pigmented anaerobes are?

Gram-negative rods or cocco bacilli

What species are black pigmented anaerobes?

Porphyromonas, Prevotella, and Tannerella

What species are anaerobic gram-positive cocci?

Peptostreptococcus

What species are strict anaerobic gram-positive bacilli?

Propionibacterium

What species are pleomorphic rods?

Actinomyces

What are facultative anaerobic gram-negative rods that may require factors X and V?

Hemophilus