Antimicrobials Flashcards
What is the MOA of PCNs?
binds PBPs and block the transpeptidase cross-linking of peptidoglycan
Activate autolytic enzymes
What, generally, are the bacteria that PCNs are used to treat?
Gram positives:
- Strep
- Staph
- N Meningitidis
What is the major adverse reaction to PCNs?
Hypersensitivity rxns
How is resistance to PCNs conferred to bacteria?
Penicillinase in bacteria to cleave the beta-lactam ring
What are the three major beta lactamase inhibitors? (CAST)
- Clavulanic acid
- Sulbactam
- Tazobactam
What are the two major anti-pseudomonal PCNs?
Ticarcillin and piperacillin
What are the three major penicillinase resistant PCNs? What bacteria do these typically treat?
Oxacillin
Nafcillin
Dicloxacillin
“Naf for staph”
What are the two major penicillinase-sensitive abx?
Ampicillin
Amox
Which has more oral availability: amoxicillin or ampicillin?
AmOxicillin has more O-ral availability
What are the bacteria that ampicillin/amoxicillin are used to treat? (HELPSS)
Haemophilus E.coli Listeria Proteus Salmonella Shigella
What is the general MOA of cephalosporins? Are these bactericidal or bacteriostatic?
Beta-lactam drugs that inhibit the cell wall synthesis, but are less susceptible to Penicillinases
bactericidal
What are the two first gen cephalosporins, and what are the three bacteria that they usually treat? (PEcK)
Cefazolin
Cephalexin
Proteus
Ecoli
Klebsiella
What are the three major third generation cephalosporins, and what are the 7 bacteria that they are used to treat? (HEN PEcKS)
Cefoxitin
Cefaclor
Cefuroxime
What is the general side effect of most cephalosporins?
Hypersensitivity rxn and it K deficiency
What other abx should never be combined with cephalosporins? Why?
aminoglycosides
Nephrotoxic
What is the only monobactam abx? MOA? Is this beta-lactam resistant?
Aztreonam
Resistant to beta lactamases
Prevents peptidoglycan cross-linking by binding to PCN-bind proteins
What is the abx that prevents peptidoglycan cross-linking by binding to PCN-bind proteins?
Aztreonam
What is the major side effect of aztreonam?
Occasional GI upset
What is the major bacterial type that aztreonam usually works against?
Gram negative rods ONLY
What two conditions are ceftriaxone used to treat?
Meningitis
Gonorrhea
What condition is ceftazidime used to treat?
Pseudomonas infx
What, generally, happens to the spectrum of activity as you progress in the generations of cephalosporins?
Increased
What is the MOA of carbapenems?
PCN-like–binds to PBPs and disrupts cell wall synthesis
Imipenem is always administered with what drug? Why?
Cilastatin to inhibit renal dehydropeptidase I
“The kill is lastin’ with cilastatin”
What are the three general categories of bacteria that carbapenems are used against?
Gram positive cocci
Gram negative rods
Anaerobes
What are the side effects of carbapenems? (2)
Seizures at high plasma levels
Skin rash
What is the MOA of vancomycin?
Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors
What are the bacteria that vanco are used to treat?
Gram positive only
What are the side effects of vanco? (“NOT trouble free”)
Nephrotoxic
Ototoxic
Thrombophlebitis
Red man syndrome
How can you prevent red man syndrome with Vanco?
Slow administration + antihistamines
What is the Mechanism of resistance against Vanco?
Amino-acid modification of D-ala D-ala
“Pay back 2 D-alas (dollars) for Vandalizing (Vanco)”
What are the two major 30s ribosome inhibitors? Which is bactericidal/bacteriostatic?
Aminoglycosides (bactericidal)
Tetracyclines (bacteriostatic)
What are the three 50s ribosome inhibitors? Which is bactericidal/bacteriostatic?
- Chloramphenicol and clindamycin (bacteriostatic)
- Erythromycin (macrolides) (bacteriostatic)
- Linezolid [variable]
What is the mnemonic for recalling the30s and 50s ribosome inhibitors?
“Buy AT 30, CCEL at 50”
MOA of aminoglycosides?
30s inhibitors–inhibit formation of initiation complex
MOA of macrolides?
50s inhibitor–inhibits the macro”slide”–blocks translocation
MOA of tetracyclines?
30s inhibitor–prevents attachment of tRNAs
MOA of linezolid?
50s inhibitor
MOA of chloramphenicol? Toxicity?
50s inhibitor– blocks peptidyl transferase
Causes anemia and gray baby syndrome
MOA of clindamycin? What infections is this used to treat?
50s inhibitor–Blocks peptide transfer
Treats infections above the waist
What is the 30s subunit responsible for? 50s?
30s is small guy on the bottom that binds mRNA, 50s is the big guy on top that gets all the tRNAs
What is the suffix of aminoglycosides?
-micin or -mycin
What are the major toxicities of aminoglycosides? (NNOT)
Nephrotoxic
Neuromuscular blockade
Ototoxic
Teratogenic
What is the MOA of resistance against aminoglycosides?
Bacterial transferase enzymes inactivate the drug by acetylation