CW Syn Inhibitors Flashcards
Beta lactams
- 4 common
- mech
- resistance
- use
- penicilin, monobactam, cephalosporin, cabapenum
- mimics D-ala D ala and binds to cross linking enzyme (prevents peptidoglycan x link)
- Gram - beta lactamases
- only kills growing cells
Penicillin
-5 common+uses
Penicillin G-acid labile, G+ and negative cocci, non-beta lactamase producing strains
Oxacillin/cloxacillin/dicloxacillin-Anti staph, can use on beta lactase producing staph, only gram +, no enterococci
Amoxicillin-extended spectrum, acid stable, better for gram-, inactivated by beta lactamases, UTI, sinusitis, otitis, LRI
Penicillin
- admin
- side effects
- resistance
- oral (not with food)/IV/IM with anesthetic and rapid excretion unless renal failure-non toxic
- 10% allergies, all are cross reacting
- Beta lactamases by up regulation, horiztonal gene transfer; transpeptidases (PBP) so penicillin binding reduced
Amoxicillin and clavulanic acid=
augmentin
What is the beta lactamase inhibitors (2)?
Clavulanic acid (class A only) and Avibactrum (class A,C,D)
- extend half life of B-lactams by inactivating B-lactamases
- much more useful on plasmid B-lactamses vs chromsomally encoded…only class A beta lactam
Cephalosporins
- general function
- 4 names
- admin/elim
- uses
- side effects
increased resistance to beta lactamases-no coverage vs extended spectrum beta lactamases
cefazolin, cefamandole, cefazidime +ceftriaxone, cefepime
oral/some IV-excreted by kvidnney-tox possible
sinusitis, otitis, LRI, MRSA (4th gen)
hypersensitivity reaction, candida superinfection, 1st generation cross reactivity with penicillins
Cephalosporins
-gen 1-4 and differences
- Cefazolin-broad spectrum, better fro gram +, only use is surgical prophylaxis, no cross BBB
- Cefamadole-extended coverage to gm-, no x reactivity with penicillin (3rd and 4th don’t either)
- cefazidime-extended gm- activity at expense of gm+ activity, some cross BBB, useful vs inducible B-lactamase production but not constitutive production
- Cefepime-Resistant to chromosomal B lactamses, good vs gm+/-, broad spectrum, crosses BBB
Monobactams
- charactersitics
- Clinical Use
- Side FX
- IV, excreted rapidly, 1 ring
- only gram - rods (pseudomonas and serration), no gm+ because doesn’t bind to PBP of gm+ or anaerobic bacteria…resistant to beta lactamases
- no tox, occasional skin rashes, no cross reactivity with penicillins
Carbapenems
- characeristics
- clinical use
- 2 examples and specific clinical use
- side fx
- cross BBB, excreted by kidney, broad spectrum (gm+/-/anerobes)
- mixed infections, resistant vs beta lactamases but not metal beta lactamses
- imipeniem-inactiveated by dehydropeptivdases in kidney and often combined with cilastatin…meropenem is resistant to dehydropeptivdases
- NVD, seizures if renal insufficiency, cross reactivity to penicillin
Non beta lactam CW inhibitors
-5 names (Vanco with 2 others)
Vanco (Dalbavacin and Oritavancin), daptomycin, polymyxins, fosftomycin, bacitracin, D-cycloserine
Vancomycin
- mech
- resistance
- use
- other
- special
- combo
- Binds to D-ala-D-ala in CW (not with enzymes used to make it)-very large drug
- enterocci switches to D-ala-D-lac and staph thicken peptidoglycan layer
- Gm+ esp staph, bactericidal for growing cells
- usually 7-10 IV (except if problem in stomach), SE minor, kidney elimination (tox if insufficient), penetrates CNS
- Dalbavancin (1 dose every several days) and Orivancin (only single dose needed)
- used with ahminoglycosides or gentamycin for enterococci
Daptomycin
- mech
- use
forms props that allow K+ loss without toxin release
-Gm+ for skin and soft tissue infections that involve MRSA
Polymyxins
- mech
- resistace
- use
- Large drug that binds LPS in outer membrane of Gm-, leading to permeability of both outer and inner membranes (perforations)
- LPS change structure
- gm- only, part of neosporin
Fosfomycin
- mech
- use
- excretion/method is ingestion
- drug combo
- Small drug that inhibits first committed step in CW synthesis (NAG converting to NAM), binds to active site cysteine of MurA (NAG to NAM) enzyme
- loss of drug transport into cell (TB MurA naturally resistant)
- Gm+and =, safe in reg, UTI
- Oral only, kidney excretion
- synergystic with other Antibiotics
Bacitracin
- mech
- use
- Side FX
- drug combo
- intereferes with lipid phosphatase that from lipid carrier peptidoglycan subunits (doesn’t add NAM/NAG to inner CW b/c phosphate in the way)
- Gm+
- increased use leads to increased freq of allergic reactions
- usally in combo with other antibiotics
