ABx II Flashcards
What are the abx that are cell wall synthesis inhibitors?
PCN Cephalosporins Monobactam Glycopeptides Polypeptides Carbapenems Phosphoenolpyruvate
What are the three general classes of protein synthesis inhibitors?
Tetracyclines
Aminoglycosides
Macrolides
What are the four abx that cause DNA damage, inhibit gyrase, or inhibit folate?
Sulfonamides
Trimethoprim
Fluoroquinolones
Metronidazole
What are the two components of the cell wall?
NAM and NAGs
N-acetylmuramic acid, N-acetylglucosamine
True or false: peptidoglycan is only found in gram positive bacteria?
False-both
What are the molecules that attach NAMs and NAGs together?
5 amino acids in a species-specific sequence
What is the enzyme that joins monomers to form NAM-NAG chains?
Transglycosylases
What are the enzymes that bind NAMs and NAGs to AAs?
Transpeptidases
What is the role of penicillin binding proteins?
play a role in the synthesis and maintenance of bacterial cell wall peptidoglycan
What is the MOA of beta-lactam abx?
Binds to and inhibits the PBP enzymes, which play a role in the synthesis and maintenance of bacterial cell wall peptidoglycan
What are the four types of beta-lactams?
PCN
Cephalosporins
Monobactam
Carbapenem
Are beta-lactams bactericidal or bacteriostatic?
Bactericidal
What is the enzyme that causes resistance to beta lactams?
Beta lactamases
What are the four major PCN compounds?
PCN G
PCN V
Amoxicillin
Methicillin
What is the most common adverse effect of beta-lactam abx?
Hypersensitivity
What are the CNS adverse effects of beta lactams?
Confusion
Hallucinations
What are the blood adverse effects of beta lactams?
Hemolytic anemia
Thrombocytopenia
What secondary infections are pts more susceptible to following beta lactam use?
Vaginal candidiasis
If there is a mild reaction to a beta lactam, should you consider another beta lactam?
Yes, but only for a MILD reaction.
If severe, then no
Are PCN G/V broad or narrow spectrum? Beta lactamase sensitive?
Narrow
Beta lactamase sensitive
Are methicillin, Nafcillin, oxacillin broad or narrow spectrum? Beta lactamase sensitive?
Very narrow
Resistant
Are ampicillin/amoxicillin broad or narrow spectrum? Beta lactamase sensitive?
Broad
Sensitive
Are piperacillin, ticarcillin, azlocillin, broad or narrow spectrum? Beta lactamase sensitive?
Extended spectrum
Sensitive
What is the drug that is coadministered with PCN abx to inhibit beta lactamase?
Clavulanic acid
What is the MOA of clavulanic acid?
Beta lactamase inhibitor
What are the key adverse effects of beta lactamase inhibitors?
Similar to PCN
What agents are used if there is a sensitivity to PCNs?
Cephalosporins
What is the MOA of cephalosporins?
Bind to PBPs
What is the key adverse effect of cephalosporins?
Hypersensitivity
What are first generation cephalosporins good to treat? Second? Third? 4th?
- Gram positive cocci
- above plus some gram -
- above and many gram neg rods
- broad
What are the two 1st generation cephalosporins?
Cefazolin
Cephalexin
What are the three second generation cephalosporins?
Cefotetan
Cefaclor
Cefuroxime
What are the four third generation cephalosporins?
Ceftriaxone
Cefotaxime
Cefdinir
Cefixime
Which generation of cephalosporins are effective in CNS treatment?
3 and 4
What is the one 4th generation cephalosporin?
Cefepime
Are any of the cephalosporin generations beta lactamase resistant? If so, which one(s)?
4th generation resistant
What is the only monobactam drug?
Aztreonam
What is the MOA of monobactams? Is it beta lactamase resistant?
Inhibit PBPs
Beta lactamase resistant
Can Monobactams penetrate the CNS?
Yes
What is the major adverse effect with monobactam?
Hypersensitivity
What are the four carbapenems?
Doripenem
Imipenem
Ertapenem
Meropenem
Imipenem needs to be administered with what? Why?
Cilastatin
imipenem is inactivated in the kidney. Cilastatin prevents this
Are most carbapenems beta lactamase resistant or sensitive? Which are outside this rule?
All Resistant
What is the MOA of carbapenems?
PBP
What are the adverse effects of carbapenems?
N/v
What are carbapenems used for?
Severe infections
What is the one glycopeptide abx?
Vanco
Does vanco penetrate the CNS?
Not really
What is the MOA of vanco?
Prevents the elongation of the peptidoglycan cell wall structure by binding to the D-ala-D-ala
MRSA should be treated with what?
Vanco + metronidazole(?)
What are the key adverse effects of vanco?
- Flushing (red man syndrome)
- Ototoxic and nephrotoxic
Vanco does not penetrate the CNS very well. Why is it so good for meningitis?
Getting some of it there via high doses is very effective
Is vanco a beta-lactam abx? MOA?
Yep
Prevents the elongation of the peptidoglycan cell wall structure by binding to the D-ala-D-ala
Red man syndrome = which abx side effect?
Vanco
What is vanco good to treat?
Gram positive +
MRSA
Enterococci
C.diff
What is the MOA of bacitracin?
Blocks incorporation of amino acids and nucleic acids into the cell wall
What is bacitracin good for treating?
Broad spectrum for both gram positive and negative
What is the key adverse effect with bacitracin?
Hypersensitivity
Which Abx prevents the elongation of the peptidoglycan cell wall structure by binding to D-ala-D-ala pentapeptide?
Vanco
Which abx blocks the incorporation of amino acids and nucleic acids into the cell wall?
Bacitracin
What is the MOA of fosfomycin?
Blocks an early step in cell wall synthesis by preventing synthesis of UDP-N-acetylmuramic acid
Which abx Blocks an early step in cell wall synthesis by preventing synthesis of UDP-N-acetylmuramic acid?
Fosfomycin
What disease is fosfomycin usually used to treat?
UTIs
What type of bacteria can fosfomycin kill well?
Both gram + and gram -
What are the three major protein synthesis inhibitor abxs?
Aminoglycosides
Macrolides
Tetracyclines
Cell wall inhibition is generally bacteriostatic or bactericidal?
Bactericidal
Protein synthesis inhibition is generally bacteriostatic or bactericidal?
Bacteriostatic
What is the target of protein synthesis inhibiting abx?
50s and 30s subunit of prokaryotes
What are the ribosomes that are in prokaryotes?
50s and 30s, which form 70s
What is the first step of prokaryotic protein synthesis?
charged tRNA binds to A site
What is the second step of prokaryotic protein synthesis?
Peptidyl tRNA peptide bond formed between growing chain and A site
What is the third step of prokaryotic protein synthesis?
newly uncharged tRNA exits
What is the fourth step of prokaryotic protein synthesis?
The now longer amino acid chain translocates to the P site
What are the 6 aminoglycosides?
- streptomycin
- gentamicin
- kanamycin
- amikacin
- tobramycin
- Neomycin
-mycin suffix indicate what abx type? What are the three exceptions?
Aminoglycosides
Erythromycin
Clarithromycin
Azithromycin
=macrolides
Are aminoglycosides bacteriostatic or bactericidal?
Bactericidal
What is the MOA of aminoglycosides?
binds to 30s and blocks formation of initiation complex
What are the two key adverse effects of aminoglycosides?
Nephrotoxic
Ototoxic
What are aminoglycosides used to treat?
Used in combination with Beta lactams to treat serious gram -
What are the three macrolides?
erythromycin
Clarithromycin
Azithromycin
What is the MOA of macrolides?
Binds to 50s subunits and impairs the translocation to the P site
What abx binds to the 30s site? 50s?
30s = aminoglycoside 50s = macrolides and tetracyclines
What are the key adverse effects of macrolides?
GI: n/v
What are macrolides used to treat? Bacteriostatic or bactericidal?
most gram +
Bacteriostatic
What are macrolides effects on the GI?
stimulate the GI Tract motility
What are the four tetracyclines?
- Tetracycline
- Minocycline
- Tigecycline
- doxycycline
What is the MOA of tetracycline?
Binds to 30 s subunit and prevent binding of a new aminoacyl to A site
What are tetracyclines used to treat?
Broad spectrum
What are the three key adverse effects of tetracyclines?
- Binds Ca (reduced growth of bone)
- Disrupts normal flora
- Skin photosensitivity
What is the difference in MOA of tetracyclines and macrolides?
both bind to 50s subunit, but tetracyclines prevent new aminoacyl T site binding, whilst macrolides prevent translocation to the P site