Abx Flashcards
Are there more gram + or - in oral flora normally?
Gram +
- Bulk of oral bacteria
- Primarily cocci or irregular shape (pleomorphic)
- Oxygen tolerance varies from facultative anaerobes to strict anaerobes
- Cell wall has thick peptidoglycan layer
Gram +
- facultative anaerobe; periodontal pockets, dental plaques, on carious teeth
Actinomyces
- facultative anaerobe; produce lactic acid; role in dentine caries rather than
enamel caries
Lactobacillus
facultative anaerobic cocci; produce lactic acid some implicated in caries
Streptococcus -
- Antagonistic to periodontal
pathogens - Predominate in a clean,
healthy mouth
Strep viridans
- Many of these bacteria found in the mouth, especially in established/subgingival
plaque - Range of oxygen tolerance but most important strict or facultative anaerobes
- Some fermentative, produce acids which other organisms use acids as an energy source,
others produce enzymes which break down tissue - Cell wall different to Gram positive with a thin peptidoglycan layer, has B-lactamase
which breaks down penicillin, also has LPS/endotoxin
Gram -
What abx is great against gram +?
Penicillin
What abx is great against gram + and -?
Augmentin
What abx is great against only anaerobes/gram -?
Metronidazole
What is the main way antibiotic resistance occurs with clindamycin?
Efflux pumps
– Arrests growth of organism
* Must have active immune system
Bacteriostatic
– Kill the organism
* Neutropenic, Meningitis, Endocarditis
Bactericidal
Are these cidal or static?
* Cell Wall Inhibitors
*Beta Lactams
*Penicillins
*Cephalosporins
*Inhibit DNA
*Fluoroquinolones
*Metronidazole
Cidal
Are these cidal or static?
* Protein Synthesis Inhibitors
– Macrolides
– Clindamycin
– Doxycycline
Static
- Bacterial suppression after antibiotic concentrations fall below MIC
*Post-antibiotic effect
For a time dependent killing, is frequency of dosing or amount of abx given more important?
Frequency of dosing
If symptoms are in low risk category (rash, itching, hives), is it okay to give drug safely?
Yes
What is MOA of b-lactam abx (pen, ceph, carbapenems)?
Bind to pen binding protein in bacterial cell wall
Are b lactams cidal or static?
cidal
What is the compound added to b lactam ring to disable b lactamases to make abx effective again?
Clavulonate
Is there more diahrrea in augmentin or pen/amox?
Augmentin
