Reviewing Material slides Exam 2

Question 1

Most odontogenic infection have why type of flora?

Answer 1

70 % have mixed flora (aerobic and anaerobic)

• 25% have pure anaerobic
• 5% have pure aerobic (rare)

Question 2

What is characteristic of Early infections

Answer 2

Aerobic streptococci
- Sensitive to penicillin

• Anaerobes appear around 3 days after onset of symptoms

Question 3

What is characteristic of Late infections

Answer 3

Anaerobes

- Frequently resistant to penicillins

Question 4

What is the drug of choice to treat mild or early odontogenic infections

Answer 4

Penicillin VK

Question 5

If patient is penicillin allergic, what is drug of choice to treat mild or early odontogenic infections? Secondary alternative

Answer 5

Clindamycin
Secondary alternative: first generation cephalosporins
-*however not good against anaerobes

Question 6

Describe spectrum of kill for Penicillin VK and bacteria it is effective against

Answer 6

Bactericidal
- against gram-positive cocci and major pathogens of mixed anaerobic infections
Narrow spectrum

Question 7

When should one take penicillin VK

Answer 7

Take 1 hour before or 2 hours after meals

- maximizes serum levels

Question 8

Adverse reactions of Penicillin VK

Answer 8

Nausea, mild diarrhea, oral candidiasis

Question 9

T or F, Amoxicillin is better than penicillin VK for treatment of odontogenic infections

Answer 9

False, there is no advantage over penicillin VK

- Less effective than penicillin VK for aerobic gram-positive cocci; similar against anaerobes

Question 10

What is amoxicillin good against?

Answer 10

H. influenzae

- acute sinus and otitis media infections

Question 11

Is the effect of Clindamycin dose dependent?

Answer 11

Yes, static (low dose) and cidal (high dose)

Question 12

Adverse effects of clindamycin

Answer 12

Primarily GI

Hypersensitivity reactions are rare

Question 13

Spectrum of kill for clindamycin

Answer 13

Broad spectrum
can be static or tidal depending on dose
- Resistant to beta-lactamase degradation

Question 14

What is the drug of choice for late odontogenic infections

Answer 14

Clindamycin

Question 15

Could penicillin still be considered for late odontogenic infections?

Answer 15

Yes, resistance rate is between 35-50%

• If patient is not responding to penicillin after 36 hours, then assume resistant pathogen is present
• Could also add metronidazole to expand spectrum of kill of penicillin

Question 16

First generation Cephalosporins are most active against what bacteria

Answer 16

Gram-positive cocci

- Not very good against many anaerobes

Question 17

Adverse event of first generation cephalosporins

Answer 17

Diarrhea (10% of users)

Question 18

T or F, patients who are intolerant to penicillins may be intolerant to cephalosporins

Answer 18

True

Question 19

If patients have full blown Type I (IgE) mediated allergic reaction is cephalosporin indicated?

Answer 19

No, it is contraindicated, up to 20% of these patients will be cross-sensitive

Question 20

Resistant anaerobes in odontogenic infections

Answer 20

• Prevotella
• Porphyromonas
• Fusobacterium nucleatum
• Campylobacter gracilis
• Fusobacterium + S. viridans = often seen in severe odontogenic infections.
  * -Typically resistant to macrocodes, use clindamycin or amoxicillin/clavulante (Augmentin)

Question 21

Beta-lactamase resistant penicillins

Answer 21

Methicillin
Oxacillin
Cloxacillin
Dicloxacillin
Nafcillin

Question 22

What are beta-lactamase resistant penicillins effective against?

Answer 22

Only effective against gram-positive cocci
No activity against anaerobes
Not indicated for late stage odontogenic infections

Question 23

Metronidazole is good for what?

Answer 23

Aggressive periodontal infections

- Do NOT use for chronic periodontitis

Question 24

Erythromycin indications:

Answer 24

No longer effective against oral organisms due to resistance or used in dentistry
-**formerly alternate drug of choice for orofacial infections for patients who were allergic to penicillins

Question 25

T or F, Clarithromycin is bacteriostatic in low doses and bactericidal at doses used for SBE prophylaxis

Answer 25

True

Question 26

What is the drug of choice for upper respiratory tract infections

Answer 26

Azithromycin (Zithromax)
- also used for STDs

• Alternate drug for antibiotic premedication