Antimicrobials Flashcards
(41 cards)
Which antibiotic affect cell wall synthesis? (general FAMILIES, and the “other” ones )
Beta-lactam, Bacitracin, Vancomycin, Cycloserine, isoniazid, ethambutol, ethionamide
Beta lactam antibiotics
- Mechanism of action
- Weakness? (ie: if a bacteria has this it might survive)
- Uses
- Types
- Mechanism: inhibit transpeptidation (final crosslinking step in peptidoglycan synthesis inhibited) and activate autolytic enzymes
- Weakness: beta-lactamases, anything without PBP (penicilling binding protein) and bacteria with autolysin inhibitors.
- Used in combination with beta lactamase inhibitors
- Penicillins, cephalosporins, monobactams, carbapenems, aztreonam, Imipenem
B-lactam side effects
Allergies:
- pen>ceph>mono
Toxicity:
- carba (seizures)>ceph (thrombophlebitis) >pen >mono
Natural Penicillin (G or V)
- Mechanism
- used against?
- V is stable against?
- Inhibits transpeptidase (beta-lactam antibiotic)
- gram + bacteria
- Pen V is acid resistant
Penicillins that are resistant to beta-lactamase
Nafcillin, oxacillin, cloxacillin
(Naf for Staph)
These penicillins can **work on gram(+) and gram(-) **!
- called **expanded spectrum **
- Ampicillin (amino penicillin), piperacillin, mezlocillin, tiracillin
- Tiracillin battles pseudonomas
these penicillins are acid resistant
- Amoxycillin (amino-penicillin), Pen V (natural), oxacillin
Common penicillin + beta lactamase drug combos
- **augmentin= **amoxicillin + clavulanic acid
- Ampicillin + sulbactam
- Zosyn, Tazomed= piperacillin + tazobactam
Penicillin vs cephalosporin?
Cephalosporine are less sensitive to beta-lactamases
Cephalosporins- First generation
- What kind of antibiotic is this?
- Effective against?
- Types?
- Beta-lactam
- gram+ bacteria for prophylaxis only because bacteria readily develop resistance to it
- cephalexin, cephalothin, cefazolin
Cephalosporins- Second generation
- What kind of antibiotic is this?
- Effective against?
- Types?
- beta lactam
- Gram (+), gram (-), bacteroides, NOT PSEUDOMONAS, increased resistance to b-lacatamase
- cefaclor, cefuroxime, cefoxitin
Cephalosporins- 3rd generation
- What kind of antibiotic is this?
- Effective against?
- Types?
- Why is this so special?
- beta-lactam
- gram+, gram-, pseudomonas, MRSA, VRE (vancomycin resistent enterococci)
- ceftazimid, cephotaxime, cephtriaxone, cefdinir
- broadest spectrum of activity, crosses BBB
Cephalosporins- 4th generation
- MOA
- effective against
- types?
- beta-lactam
- G+ and G-, broadest of 5 generations
- Cefepime
Cephalosporin 5th Generation
- MOA
- used against?
- types?
- beta-lactam
- MRSA, drug resistant S Pnemoniae, NOT PSEUDMONOMS
- ceftaroline
Monobactams
- mechanism?
- Effective against?
- types?
- Resistant to?
- Beta lactam (inhibits transpeptidase and activates autolytic enzymes)
- Gram (-) ONLY (not against G+ or anaerobes)
- aztreoname
- Fully resistant to b-lactamases
Carbaoenems
- Mechanism of action
- Effective against
- types
- Down-side?
- beta-lactam
- broad spectrum G+ and G-
- imipenem, ertapenem, meropenem (less toxic)
- toxic
pen=pan= broad spectrum
penem= “pen him!” = kill him = it’s toxic —-I’m trying :-/
Bacitracin
- Mechanism of action
- Used on?
- Side effects
- structural feature we should know?
- blocks bactoprenol dephosphorylation
- topical on G+ with other drugs
- poorly absorbed, renal toxicity
- LARGE!!! cannot cross G- membrane, poorly absorbed
Glycopeptides Antibiotics
- MOA
- Weak against
- Used for?
- Types
- What should be know about shape?
- binds the end of the aa chain to block transglycosylation and transpeptidation
- VanA plasmid and VanB chromosome-use ala-lactate instead of ala-ala
- resistant staph, staphylococci, enterococci, NOT G- BACTERIA
- Vancomycin, Telavancin,
- Large- given via IV because can’t be absorbed by GI tract. Also won’t go into gram- bacteria
Cycloserine
- MOA
- Uses
- What else should we know?
- D-ala analog- inhibits alanine racemase
- sometimes for UTI, 2nd line drug for TB.
- neurtoxic, use carefully
We kill the cell membrane.
Polymyxins (colistin) and daptomycin (cubcin)
THIS MEANS THEY CAN AFFECT OUR HUMAN MEMBRANES TOO!
Polymyxin
- MOA
- Uses
- Type
- dissolves PE in G- membranes. We have PE too.
- Toxic. Used topically or as last resort for resistant bugs
- Colistin
Daptomycin
- MOA
- Uses
- Types
- cyclic lipopeptide that dissolves in the membrane and disrupts membrane potential
- G+ cocci, MRSA- given IV with B-lactams
- Cubicin
Antimetabolites
- MOA
- Weak against
- Used agaonst
- types
- inhibit PABA, DHF, THF, Pyrimidines =inhibition of protein/nucelic acid synthesis. I guess PABA gets incorporated into DHP?
- Things that make tons of PABA
- Nocardia. Synergistic with TMP and SMX for UTI, salmonella, shigella.
Trimethoprin
- MOA
- part of what group of antibiotics?
- Inhibits dihydrofolate reductase= no folic acid
- part of the antimetbolics antibiotics