Clinical Microbiology Fifth Year

1. Antibiotic Use in Orofacial
Dental Infection
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2. INTRODUCTION
 This presentation will review the
evaluation and management of orofacial
infections with emphasis on:
■
■
■
Antibiotic Therapy
Indications for Prophylaxis
Antifungal Agents
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3. ASSESSMENT
 Requires a complete medical history and exam of the
head and neck region with awareness to systemic
factors as part of a comprehensive dental
examination
 Identify local and/or systemic signs and
symptoms to support the diagnosis of infection:
< erythema, warmth, swelling, and pain >
< malaise, fever ( >38 c), chills >
 Loss of function
< dysphagia, trismus, dyspnea >
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4. DIAGNOSIS: Infection
 Determine etiology
> odontogenic
> trauma wound, animal bite
> TB, fungi, viral,
actinomycoses
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5. DIAGNOSIS (CON’T)
 Determine cellulitis versus abscess
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6. TREATMENT of INFECTION
 Remove the cause of infection, most important
of all, drain the pus by either spontaneously or
surgically
 Antibiotics are merely an adjunctive therapy.
Drainage
Host defense
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Antibiotics

7. INDICATION for ANTIBIOTICS
1. Severity of the infection
 Acute onset
 Diffuse swelling involves fascial spaces
2. Adequacy of removing the source of infection
 When drainage can’t be established immediately
3. The state of patients’ host defense
 When the patient is febrile
 Compromised host defenses
 For prophylaxis
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8. MICROBIOLOGY
 Most oral infections are mixed in origin
consisting of aerobic and anaerobic Gram
positive and Gram negative organisms
 Anaerobes predominant (75%)
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9. COMMONLY USED A/B
 Mechanism of the antibiotics

10. COMMONLY USED A/B
1. Groups of Penicillin
 First choice for odontogenic infection
 G(+) cocci and rod, spirochetes, anaerobes
 0.7~10% hypersensitivity
 Nature: penicillin G (IV), penicillin V (Oral)
 Penicillinase-resistant: oxacillin, dicloxacillin
 Extended spectrum: ampicillin, amoxicillin
 Combine β-lactamase inhibitor: augmentin
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11. 2. Cephalosporin
 More resistance to penicillinase
 G(+) cocci, many G(-) rods
 Third generation: Pseudomonas aeruginosa
 Second choice (less effect for anaerobes)
First generation
Cefazolin
U-SAVE-A
Tydine
Second generation
Keflor
Ucefaxim
Third generation
Claforan
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Forth generation
Cefepime

12. 3. Clindamycin
 G(+) cocci
 Bacteriostatic -> bactericidal
 Second-line drug: should be held in reserve to
treat those infections caused by anaerobes
resistant to other antibiotics
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13. 4. Aminoglycoside
 G(-) aerobes, some G(+) aerobes eg S. aureus
 Poorly absorbed from GI tract
 Adjustment of dosage in renal dysfunction
 Drugs: Gentamicin, Amikacin, Amikin
 Combined with penicillin or cephalosporin
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14. 5. Metronidazole*
 Only for obligate anaerobes
 Can cross blood-brain barrier
 To treat serious infections caused by anaerobic
bacteria, combined with β-lactam A/B
 Effective against Bacteroides species, esp. in
periodontal infections
 Drugs: Anegyn, Flagyne
 Avoid in pregnant women
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15. 6. Vancomycin
 G(+), most anaerobes, some G(-) cocci (Neisseria)
 Given intravenously, BP should be monitored
 Adjustment of dosage in renal dysfunction
 Use as a substitute for penicillin in the
prophylaxis of the heart valve patient
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16. 7. Chloramphenicol
 Wide spectrum, highly active against anaerobes
 Limited to severe odontogenic infection
threatening to the eye or brain
 Severe toxicity
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17. `
8. Erythromycin
 G(+) cocci, oral anaerobes
 Bacteriostatic
 Second choice for odontogenic infections
 Indication for out-patients with mild infection
 Drug resistence: 50% of S. aureus, Strep. viridans,
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18. 9. Tetracycline*
 Only against anaerobes
 Contraindications: pregnant women, children <12
 Limited usefulness in orofacial infection
 Use as adjunctive therapy for refractory
periodontitis
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19. SELECTION of A/B
 Use Empiric therapy routinely
 Use the narrowest spectrum antibiotics
 Use the antibiotics with the lowest toxicity and
side effects
 Use bactericidal antibiotics if possible
 Be aware of the cost of antibiotics
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20.  Empiric Antibiotics in Oro-Facial Infection
■
First-line
Penicillin 3MU IVA q6h -> Cefazolin 1000mg q6h
Gentamycin 60-80mg IVA q8h-q12h
■
Second line (3A)
Augmentin 1200mg q8h + Amikin 375mg q12h + Anegyn
■
Mild infection
Amoxicillin 250mg #2 PO q8h
Clindamycin 300mg PO q6h
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21.  Side Effect of Commonly Used Antibiotics
1. Penicillin
hypersensitivity
2. Cephalosporin
hypersensitivity
3. Clindamycin
diarrhea, pseudomembrane colitis
4. Aminoglycoside
damage to kidney, 8th neurotoxicity
5. Metronidazole*
GI disturbance, seizures
6. Vancomycin
8th neurotoxicity, thrombophlebitis
7. Chloramphenicol bone marrow suppression
8. Erythromycin
mild GI disturbance
9. Tetracyclin*
tooth discoloration, photosensitivity
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22. PROPHYLAXIS
 Indications

23. PROPHYLAXIS (CON’T)
 Dental procedures recommended for prophylaxis

24. PROPHYLAXIS (CON’T)
 Regimen

25. ANTIFUNGAL AGENT
 Most of fungal infection are from candida
 Commonly used drugs:
(1) Nystatin (Mycostatin)= PO 4-600,000 U qid
(2) Amphotericin B= IV for severe systemic infec.
(3) Fluconazole, Ketoconazole
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26. Parmason Gargle
 0.2% Chlorhexidine gluconate
 Against G(+), G(-)
 Reduce pain and inflammation, enhance healing
 Indication: immunocompromised patient, C/T R/T
(prophylaxis mouthrinse reduce oral mucositis)
 Use: 2-3 times daily,10-20cc/ time, 20-30sec.

27. Anti-Virals used in dentistry
 Topical Acyclovir is useful for recurrent
herpetic infections, but must be started early in
the prodromal phase to have a worthwhile effect.
 Oral Acyclovir, Valacyclovir and Famciclovir
are efficacious and safe for the treatment of the
first episode and recurrent genital herpes
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28.  FOSCARNET - Class: Non-nucleoside DNA Polymerase
Inhibitors
Indications: "HSV, CMV
Treatment of acyclovir resistant HSV infections in AIDS
patients
Acyclovir resistant VZV
MOA/PCOL: Blocks the pyrophosphate binding site on
viral DNA polymerase
Adverse Effects/Other: "Not a purine or pyrimidine
analog, Phosphono formate analog
Toxic: renal impairment, CNS disturbance, leukopenia,
liver dysfunction
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