Antimicrobial Therapy Flashcards
Antimicrobial therapy
folic acid synthesis
- Sulfonamides
- Trimethoprim
Antimicrobial therapy
DNA Topoisomerases
- Fluoroquinolones
- Quinolone
Antimicrobial therapy
damages DNA
Metronidazole
Antimicrobial therapy
mRNA synthesis
Rifampin
Antimicrobial therapy
protein synthesis (50S)
- Chloramphenicol
- Clindamycin
- Linezolid
- Macrolides
- Streptogramins
Antimicrobial therapy
protein synthesis (30S)
- Aminoglycosides
- Tetracyclines
Antimicrobial therapy
cell wall synthesis (peptidoglycan cross linking)
- penicillinase-sensitive penicillins
- penicillinase-resistant penicillins
- antipseudomonals
- cephalosporins
- carbapenems
- monobactams
Antimicrobial therapy
cell wall synthesis (peptidoglycan synthesis)
Glycopeptides
Penicillin G, V
administration
- prototype ß-lactam antibiotics
- penicillin G - IV & IM
- penicillin V - oral
Penicillin G, V
mechanism
- bind PBPs (transpeptidases)
- block transpeptidase cross-linking of peptidoglycan
- activate autolytic enzymes
Penicillin G, V
clinical use
penicillinase
- gram (+) organisms
- S. pneumoniae, S. pyogenes, Actinomyces
- N. meningitidis, T. pallidum
- bactericidal: gram (+) cocci, gram (+) rods, gram (-) cocci, spirochetes
- penicillinase sensitive
Penicillin G, V
toxicity
- hypersensitivity rxns
- hemolytic anemia
Penicillin G, V
resistance
penicillinase in bacteria cleaves ß-lactam ring
type of ß-lactamase
Ampicillin, amoxicillin
mechanism
- same as penicillin
- wider spectrum
- penicillinase sensitive
- combine w/ clavulanic acid to protect against ß-lactamase
Ampicillin, amoxicillin
clinical use
HELPSS kill enterococci
- extended-spectrum penicillin
- Haemophilus influenzae
- E. coli
- Listeria monocytogenes
- Proteus mirabilis
- Salmonella
- Shigella
- enterococci
Ampicillin, amoxicillin
toxicity
- hypersensitivity rxns
- rash
- psuedomembranous colitis
Ampicillin, amoxicillin
resistance
- penicillinase in bacteria cleaves ß-lactam ring
- ß-lactamase
Oxacillin, nafcillin, dicloxacillin
mechanism
- same as penicillin
- narrow spectrum
- **penicillinase resistant **
- bulky R group
- blocks access of ß-lactamase to ß-lactam ring
Oxacillin, nafcillin, dicloxacillin
clinical use
S. aureus (except MRSA)
Oxacillin, nafcillin, dicloxacillin
toxicity
- hypersensitivity rxns
- interstitial nephritis
Ticarcillin, piperacillin
mechanism
- same as penicillin
- extended spectrum
Ticarcillin, piperacillin
clinical use
- Pseudomonas spp.
- gram-negative rods
- susceptible to penicillinase
- **use w/ ß-lactamase inhibitors **
Ticarcillin, piperacillin
toxicity
hypersensitivity rxns
ß-lactamase inhibitors
CAST
- Clavulanic Acid
- Sulbactam
- Tazobactam
Cephalosporins
mechanism
- ß-lactams
- **inhibit cell wall synthesis **
- less susceptible to penicillinases
- bactericidal
1st generation cephalosporins
**cefazolin, cephalexin **
- gram (+) cocci
- PEcK
- Proteus mirabilis
- E. coli
- Klebsiella
_______ used prior to surgery to prevent S. aureus wound infections.
Cefazolin
2nd generation cephalosporins
**cefoxitin, cefaclor, cefuroxime **
- gram (+) cocci
- HEN PEcKS
- Haemophilus influenzae
- Enterobacter aerogenes
- Neisseria spp.
- Proteus mirabilis
- E. coli
- Klebsiella pneumoniae
- Serratia marcescens
3rd generation cephalosporins
**ceftriaxone, cefotaxime, ceftazidime **
- serious gram (-) infections resistant to other ß-lactams
- Ceftriaxone - meningitis & gonorrhea
- Ceftazidime - Psuedomonas
4th generation cephalosporins
cefepime
- increased activity against Pseudomonas & gram (+) organisms
5th generation cephalosporins
ceftaroline
- broad gram (+) & gram (-) organism coverage
- MRSA, not Pseudomonas
Cephalosporins
toxicity
- hypersensitivity rxns
- vitamin K deficiency
- low cross-reactivity w/ penicillins
- increased nephrotoxicity of aminoglycosides
Aztreonam
mechanism
- monobactam
- resistant to ß-lactamases
-
prevents peptidoglycan cross-linking
- binds PBP
- synergistic w/ aminoglycosides
- no cross-allergy w/ penicillins
Aztreonam
clinical use
- gram (-) rods only
- penicillin-allergic patients
- patients w/ renal insufficiency who can’t tolerate aminoglycosides
Aztreonam toxicity
- usually non-toxic
- occasional GI upset
Carbapenems
- Imipenem
- Meropenem
- Ertapenem
- Doripenem
Carbapenems
mechanism
Imipenem
- broad-spectrum, ß-lactamase resistant
- admin w/ cilastatin
- inhibitor of renal dehydropeptidase I
- decreased inactivation of drug in renal tubules
Carbapenems
clinical use
- gram (+) cocci, gram (-) rods, anaerobes
- wide spectrum
- **life-threatening infections or when other drugs have failed **
- Meropenam has decreased risk of seizures
Carbapenems
toxicity
- GI distress
- skin rash
- CNS toxicity (seizures)
Vancomycin
mechanism
- inhibits cell wall peptidoglycan formation
- binds D-ala-D-ala
- bactericidal
Vancomycin
clinical use
- gram (+) only
- serious, multidrug-resistant organisms
- MRSA, enterococci, C. difficile
Vancomycin
toxicity
NOT trouble-free
- Nephrotoxicity
- Ototoxicity
- Thrombophlebitis
- diffuse flushing
- red man syndrome