Microbiology 1 - Oral

Question 1

What are some of the most common flora found in the upper Resp. tract?

Answer 1

Aerobes: Streptococcus, Neisseria, Haemophilus

Anaerobes: Peptostreptococcus, Veillonella, Actinomyces, Fusobacterium

Question 2

Describe the formation of dental plaque

Answer 2

1. Pellicle (salivary glycoproteins) coats the clean tooth (hours)
2. Pellicle colonized by G+ (Strep mutans, Actinomyces) Primary colonizes.
3. Secondary colonizers adhere to Gram +, mostly Gram - (Fusobacterium nucleatum, prevotella, capnocytophaga) (1-3 days)
4. Tertiary colonizers (5days) Aggregatibacter actinomycetemcomitans

Question 3

Identify predominant organisms that cause dental caries and periodontitis.

Answer 3

Infectious disease: endogenous (strep mutans), Produce lactic acid as they metabolize sugars (erodes enamel)

Periodontitis: progressive loss of bone around teeth which may lead to loosening ad eventual loss of teeth (aggregatibacter actinomycetemcomitans)

Question 4

Describe the progression of bacterial endocarditis and signs/symptoms.

Answer 4

Infection of the lining of the heart or valves, that damages and may destroy the valves.

S/x Chronic fever, fatigue, headache, night sweats, enlarged spleen, Splinter hemorrhages, Osler notes on fingers/toes

1. bacteremia (oral bacteria enter blood stream)
2. Travel to heart and adhere to themselves (form biofilm vegetations)
3. Bacteria damage valves over time
4. Murmurs result from changes in blood flow

Question 5

What organisms cause bacterial endocarditis.

Answer 5

50-60% Strep veridans/mutans

Aggregatibacter - G- Rods, facultative anaerobes, fastidiuous

Question 6

Describe actinomycosis

Answer 6

Caused by actinomyces isrealii

Colonizes human mucosal surfaces

Gram pos. branching rods, anaerobic, non-sporeforming.
“LUMPY JAW”

Sulfur granules

Question 7

Explain oral candidiasis

Answer 7

Aka thrush
Produce pseudohyphae and hyphae

Opportunistic

At risk: infants, dentures, diabetes, antibiotics, chemotherapy AIDs

Question 8

Describe HSV1

Answer 8

DS DNA enveloped virus

“Dew drop on a rose petal”

Tzanck smear microscopic examination shows multinucleated giant cells (syncitia) and Cowdry Body inclusions

Question 9

Describe Hand Foot and Mouth

Answer 9

Enterovirus (SS+ RNA naked virus)

Coxsackievirus A16

Lesions in oral cavity followed by palms and soles

Self Limiting