Antibiotics Flashcards
(114 cards)
What are the MC and second MC antibiotic MOAs?
1 = inhibition of cell wall synthesis
Important aerobic gram positive cocci
1) Staphylococci (S. aureus, Coag-negative staph)
2) Streptococci (S. pneumoniae,Group B Strep, Viridans Strep)
3) Enterococci (E. faecalis, E. faecium)
Important aerobic gram negative rods
1) E. coli
2) K. pneumoniae
3) Serratia (Enterobacteriaceae)
4) H. influenza
5) . P. aeruginosa
Important aerobic gram negative cocci
1) Moraxella catarrhalis
2) N. gonorrhoeae
3) N. meningitidis
Important atypical respiratory aerobes
1) Legionella spp.
2) Mycoplasma pneumoniae
3) Chlamydia pneumoniae
Important anaerobes
1) True anaerobes (gut): Bacteroides fragilis and C. diff
2) Oral anaerobes: Prevotella and Peptostreptococcus
MIC
minimum inhibitory concentration
(dilution test to determine microbial sensitivity)
Note: many drugs will not reach their MIC in certain tissues
MBC
minimum bactericidal concentration
-cidal = kills bacteria
(dilution test to determine microbial sensitivity)
Penicillins MOA
B-Lactam
inhibit cell wall synthesis by binding to penicillin binding proteins (PBPs)
How are Penicillins differentiated?
By their side chains
different penicillins target different bacteria and have different resistance profiles
Penicillins resistance
1) B-lactamases - can cleave beta-lactam ring in center of Penicillins and render them inactive; doesn’t affect all penicillins
2) Altered PBPs
Natural penicillins
1) Penicillin G (IV)
2) Penicillin VK (PO)
Aminopenicillins
1) Amoxicillin
2) Ampicillin
3) Amoxicillin + Clavulanate (Augmentin)
Penicillinase-resistance penicillins
1) Methicillin
2) Nafcillin
3) Cloxacillin
4) Dicloxacillin
Extended-Spectrum Penicillins
1) Piperacillin
2) Ticarcillin
**These are IV only
Natural Penicillins spectrum
1) Gram-positive cocci
2) Neisseria
3) Most oral anaerobes
*Not effective against gram-neg aerobes or beta-lactamase producing organisms
What is Penicillins the DOC for?
N. meningitidis
Syphilis
Penicillinase-resistance penicillins spectrum
1) Gram-positive cocci (including B-lactamase producers)
2) some Streptococci
3) Oral anaerobes
*Not effective against gram-negative aerobes
Penicillinase-resistance penicillins are DOC for
MSSA (methicillin sensitive Staph. aureus)
Aminopenicillins MOA
binds to PBPs and inhibits synthesis in bacterial cell wall
Aminopenicillins spectrum
1) Some gram negative organisms
2) some gram positive organisms (Strep, Enterococci)
3) oral anaerobes
*Note effective against B-lactamase producing organisms
T/F: Aminopenicillins are the DOC for UTIs
FALSE
only use for UTI if you know its caused by enterococci
Extended-Spectrum Penicillins
1) Gram negative infx (esp. good again Pseudomonas aeruginosa)
2) Some gram positive (Strep, Staph, Mb Enterococci)
3) Oral anaerobes
4) some true anaerobes
Extended-Spectrum Penicillins are indicated for
severe infections
esp. useful for tx Pseudomonas
Broad Spectrum