Antibiotics: Cell wall inhibitors Flashcards
What antibiotics are bacteriostatic?
Tetracyclines, linezolid, macrolides, clindamycin, and sulfonamides
What antibiotics are bacteriocidal?
B-lactams, glycopeptides, daptomycin, aminoglycosides, quinolones, metronidazole
What is the MOA of B-lactams, cephalosporins, monobactam, and carbapenems?
Inhibit transpeptidase PBPs which is an enzyme that catalyzes the final cross-linking step in peptidoglycan synthesis –> leads to cell lysis aka bactericidal
- Note that cephalosporins are more stable
What are first generation penicillins?
Penicillin G (iv) and penicillin V (po)
What are indications for penicillin G and penicillin V?
(+)= s. pyogenes
- Others include for spirochetes like syphilis
What are second generation penicillins?
Methicillin, oxacillin, dicloxacillin, nafcillin
What are indications for oxacillin, dicloxacillin, and nafcillin?
(+)= S. aurerus (MRSA or MSSA)
What are third generation penicillins?
Amoxicillin and ampicillin
What are indications for amoxicillin and ampicillin?
“HELP”
(+)= streptococcus, listeria monocytogenes
(-)= haemophilus influenza, escherichia coli, proteus mirabilis
What are B-lactamase inhibitors?
Clavulanic acid and tazobactam (only used in combination w amoxicillin)
What are indications for amoxicillin + B-lactamase inhibitors?
“HNPEK” + anaerobes
(+)= streptococcus, staphylococcus, enterococcus faecalis, listeria monocytogenes
(-)= haemophilus influenza, neisseria ssp, proteus mirabilis, escherichia coli, klebsiella
What are fourth generation penicillins?
Piperacillin (iv)
What are indications for piperacillin + B-lactamase inhibitors?
“HNPEK/CaPES”
(+)= streptococcus, staphylococcus, enterococcus faecalis, listeria monocytogenes
(-)= haemophilus influenza, neisseria ssp, proteus mirabilis, escherichia coli, klebsiella
(-)= citrobacter, acinetobacter, pseudomonas, enterobacter, serratia
What are side effects for penicillin, monobactams, and carbapenems?
- Hypersensitivity reactions (rash, fever, joint swelling, pruritus, leukopenia, anaphylactic shock)
- GI distress (diarrhea)
What are first generation cephalosporins?
Cefazolin and cephalexin
What are indications for cefazolin and cephalexin?
“PEK”
(+)= streptococci and staphylococci
(-)= proteus mirabilis, escherichia coli, klebsiella
T/F: cefazolin can be used for surgical prophylaxis
True
What are second generations cephalosporins?
Cefuroxime, cefoxitin, and cefotetan
T/F: cefazolin can be used for meningitis as well
False, only the second gen cefuroxime can be used for meningitis since it passes the BBB
What are indications for cefuroxime, cefoxitin, and cefotetan?
“HNPEK”
(+)= streptococci and staphylococci
(-)= haemophilus influenzae, neisseria ssp, proteus mirabilis, escherichia coli, klebsiella
What else can cefoxitin and cefotetan be used for?
They are also active against B.fragilis
What are third generation cephalosporins?
Ceftriaxone, cefotaxime, and ceftazidime
What are indications for ceftriaxone, cefotaxime, and ceftazidime?
“HNPEK”
(+)= streptococci and staphylococci
(-)= haemophilus influenzae, neisseria ssp, proteus mirabilis, escherichia coli, klebsiella
“CaPES”
- Citrobacter, acinetobacter, pseudonomas (only ceftazidime), enterobacter, serratia
- Also used for empirical management of sepsis and meningitis
What is the fourth generation cephalosporin?
Cefepime (iv)
What are indications for cefepime?
Used for nosocomial infections
- Gram +, -, and pseudomonas
What is the fifth generation cephalosporin?
Ceftaroline (iv)
What are indications for ceftaroline?
(+)= broad + MRSA
(-)= broad but not active against pseudomonas
What are side effects of cephalosporins?
- Hypersensitivity
- GI distress
- Intolerance to alcohol (disulfiram like effect) and specifically from cefotetan
- Potentially nephrotoxic (1st gen mainly)
What drug is a monobactam?
Aztreonam (iv)
What are the indications of aztreonam?
“HNPEK + CaPES” aka aerobe gram negative rods
(-)= haemophilus influenzae, neisseria ssp, proteus mirabilis, escherichia coli, klebsiella
(-)= citrobacter, acinetobacter, pseudomonas, enterobacter, serratia
What drug would you use if you are allergic to penicillin and cephalosporin & need activity against a gram-negative rod?
Use aztreonam
What drug is a carbapenem?
Meropenem
What are indications of carbapenems?
- Gram positive cocci
- Gram negative rods (pseudomonas)
- Anaerobes
- Empiric tx for severe life threatening infections like sepsis and meningitis
What drug is a glycopeptide?
Vancomycin
What is the MOA of vancomycin?
Bind to D-Ala-D-Ala to prevent their cross-linking and is bactericidal
What are indications for vancomycin?
Only effective against gram positive= streptococci, MRSA, enterococci, c diff
What are side effects for vancomycin?
- Hypersensitivity (flushing but decrease this by infusing slowly)
- Ototoxicity (mainly if used w aminoglycosides)
- Nephrotoxicity
Which drug is a cell membrane active agent or lipopeptide?
Daptomycin
What is the MOA of daptomycin?
Interfere w inner membrane and create channels (pores) where bacterial electrolytes leak which disturbs homeostasis and is bactericidal
What are indications for daptomycin?
Only active against gram += VRE, MRSA, VRSA and do NOT use in pneumonia
What are side effects seen with daptomycin?
Can cause muscle pain and weakness so monitor CK activity (and interact w statins)
