micro - antimicrobials Flashcards
inhibiting peptidoglycan cross-linking –> block cell wall synthesis
penicillin, methicillin, ampicillin, piperacillin
cephalosporins, zaztreonam, imipenem
block peptidoglycan synthesis
bacitran and vancomycin
inhibit folic acid synthesis (methylation) –> block nucleotide synthesis
sulfonamides, trimethroprim
block DNA topoisomerase
fluoroquinolones
block mRNA synthesis
rifampin
damage DNA
metronidazole
block protein synth at 50S ribosomal unit
chloramphenicol, clindamycin, linezolid, macrolides, streptogramins (-pristin)
block protein synth at 30S ribosomal unit
aminoglycosides, tetracycline
macrolides MOA
block 50S
penicillin general
prototype beta lactam, blocks peptidoglycan cross linking - inhibits cell wall synthesis
penicillin MOA
binds penicillin-binding protein (transpeptidases) –> block transpeptidase cross-linking of peptidoglycan
activate autolytic enzymes
penicillin clinical use
gram positive organisms - strep pneumo, strep pyogenes, actinomyces
neisseria meningitis, treponema pallidum, syphilis
penicillin toxicity
hypersensitivity rxn
hemolytic anemia
penicillin resistance
beta-lactamase cleaves beta-lactam ring
penicillin G
IV and IM form
penicillin V
oral
penicillin bactericidal vs.
gram positive cocci and rods, gram negative cocci, and spirochetes
penicillinase-resistant penicillins
NOD IF U RESIST
nafcillin, oxacillin, dicloxacillin
PRP MOA
same as penicillin - bind PBP (transpeptidase) -> inhibit transpeptidase crosslinking of peptidoglycan –> inhibit cell wall synthesis
narrow spectrum!
PRP MOA of resistance to penicillinase
bulky R group blocks access of beta-lactamase to beta-lactam group
which PRP used for staph
nafcillin
PRP clinical use
staph aureus (except MRSA)
MRSA resistance MOA
altered penicillin binding protein target site
PRP toxicity
hypersensitivty rxn
interstitial nephritis
aminopenicillins
ampicillin and amoxicillin
aminopenicillins MOA
same as penicillin *bind penicillin binding protein (transpeptidases) –> inhibit transpeptidase crosslinking of peptidoglyan –> inhibit cell wall synthesis
wider spectrum!
aminopenicillin with greater oral bioavailability
amoxicillin
aminopenicillin clinical use
extended spectrum penicillin (AMPED UP) - HELPSS kill enterococci
h flu, e coli, listeria monocytogenes, proteus mirabilis, salmonella, shigella, enterococci
aminopenicillin toxicity
hypersensitivity rxn, ampicillin rash, pseudomembranous colitis
aminopenicillin resistance
beta lactamase cleaves beta lactam ring ***add CLAVULANIC acid to help protect
antipseudomonals
ticarcillin, pipercillin
antipseudomonals MOA
same as penicillin - extended spectrum
antipseudomonals clinical use
pseudomonas and gram negative rods
suscept to beta-lactamase –> use with beta-lactmasease inhibitors
antipseudomonals toxicity
hypersensitivity rxn
beta lactamse inhibitors
CAST - clavulanic acid, sulbactam, tazobactam
often added to penicillin antibiotics to protect antibiotic from destruction by beta-lactamase
cephalosporins MOA
beta lactam - block peptidoglycan cross linking –> inhibit cell wall synthesis **lessss susceptible to beta-lactamase
bactericidal
not covered by cephalosporins
LAME = listeria, atypicals (chlamydia/mycoplasma), MRSA and enterococci
which cephalosporin blocks MRSA
ceftaroline
cephalosporins 1st generation
cefazolin, cephalexin
cephalosporins 1st generation bugs
PEcK - gram positive cocci, proteus mirabilis, e coli, klebsiella pneumoniae
what is used prior to surgery to prevent staph aureus wound infections
cefazolin
cephalosporins 2nd generation
cefoxitin, cefaclor, cefuroxime
cephalosporins 2nd generation bugs
HEN PEcKS
gram positive occci, h flu, enterobacter aerogenes, neisseria, proteus mirabilis, e coli, klebsiella pneumo, serratia marcescens
cephalosporins 3rd generation
ceftriaxone, cefotaxime, ceftazidime
cephalosporins 3rd generation bugs
serious gram negative infections resistant to other beta-lactams
cephalosporins 4th generation
cefepime
cephalosporins 4th generation bugs
pseudomonas and gram positive
ceftriaxone
meningitis and gonorrhea
ceftazidime
pseudomonas
cephalosporins toxicity
HS rxn, vitamin K deficiency
low cross-reactivity with penicillins
increase nephrotoxicity of amino glycosides
aztreonam MOA
prevents peptidoglycan cross linking by binding PBP3
synergistic with amino glycosides
no cross-allergenicity with penicillins
monobactam resistant to beta-lactamases
aztreonam
aztreonam clinical use
gram negative rods ONLY
for penicillin allergic patients and those with renal insufficiency who cant tolerate amin glycosides
aztreonam toxicity
nontoxic - occasional GI upset
imipenam
broad spectrum beta-lactamase resistant carbapenem
imipenam MOA
inhibit peptidoglycan cross linking –> inhibit cell wall synth
always administered with cilastatin to decrease inactivation of drug in renal tubules
kill is lastinnn with cilastatin
cilastatin MOA
inhibits renal dehydropeptidase I
imipenam clinical use
gram positive cocci, gram neg rods and anaerobes
SE limit use to life-threatening infections or after other drugs failed
meropenem
reduced risk of seizures and stable to dehydropeptidase I
carbapenem toxicity
GI distress, skin rash, and CNS toxicity (seizure) and high plasma levels
newer carbapenems
ertapenem and doripenem
vancomycin MOA
binds D-ala D-ala portion of cell wall precursors –> inhibits cell wall peptidoglycan formation
*bactericidal
vancomycin clinical use
gram positive
serious multidrug resistant organisms like MRSA< enterococci and c diff
pseudomembranous colitis c diff
oral vancomycin
MRSA
vancomycin
vancomycin toxicity
NOT - nephrotoxicity, ototoxicity, thrombophlebitis
well tolerated in general
red man syndrome
diffuse flushing from vancomycin
how to prevent red man syndrome
pretx w antihistamines and slow infusion rate
30S inhibitors
aminoglycosides(bacteriCidal) and tetracycline (bacteriosTatic)
50s inhibitors
chloramphenicol, clindamycin, erythromycin (macrolides), linezolid
mostly bacteriostatic
aminoglycosides
GNATS - gentamicin, neomycin, amikacin, tobramycin, streptomycin
aminoglycosides MOA
block protein synth at 30S - bactericidal
inhibit formation of initiation complex (A initates alphabet) –> mRNA misreading
block translocation
require O2 for uptake (aminO2glycosides)
aminoglycosides clinical use
severe gram negative rod infections
synergistics with beta-lactams
aminoglycoside for bowel surgery
neomycin
aminoglycoside toxicity
NNOT - nephrotoxicity, neuromusc blockage, ototoxicity, teratogen
aminoglycoside plus cephalosporin
nephrotoxicity
aminoglycoside plus loop diuretics
ototoxicity
aminoglycoside resistance
transferase enzymes inactive drug via acetylation, phosphorylation or adenylation
tetracyclines
tetracycline, doxycycline, demeclocycline, minocycline
demeclocycline
ADH antagonist - diuretic in SIADH
tetracyclines MOA
block protein synth @ 30S; bacteristatic
prevent attachement of aminoacyl-tRNA - limited CNS penetration
doxycycline
fecally eliminated - used in pts w/ renal failure
tetracycline warnings
dont take with milk, antacides or iron-containing preps bc divalent cations inhibit absorption in gut
tetracycline clinical use
borrelia burgdorferi, m. pnuemoniae
acumulate intracellularly = very effectives vs rickettsia and chlamydia
tetracycline toxicity
GI, discolor teeth + inhibit bone growth in kids, photosensitivity
tetracycline CI
preggers
tetracycline resistance
decrease uptake in cells or increase efflux by plasmid-encoded transport pumps
macrolides
azithryomycin, erthryomycin, clarythromycin
macrolides MOA
block protein synth at 50S - bacteriostatic block translocation (macroSLIDES) bind 23S rRNA of 50S ribosomal subunit
macrolides clinical use
atypical penuomnia (mycoplasma, chalmydia, legionella), STD (chlamydia), gram pos cocci (step infections in pts allergic to penicillin)
macrolides toxicity
MARO - motility issues, arrhythmia due to QT prolongation, acute cholestatic hepatitis, rash, eosinophilia
macrolides increases serum concentration of
theophyllines, oral anticoagulants
macrolides resistance
methylation of 23S rRNA binding site
chloramphenicol MOA
blocks protein synth at 50S - bacteriostatic
blocks peptidyl transferase
chloramphenicol clinical use
meningitis (h flu, n. men, strep pneumo)
conserv use to to toxicity but cost allows use in developing countries
chloramphenicol toxicity
anemia (dose), aplastic anemia
gray baby syndrome
chloramphenicol toxicity
premature infants lack liver UDP-glucoronyl transferase
chloramphenicol resistance
plasmid-encoded acetyl transferase inactivates drug
clindamycin MOA
blocks protein synth at 50 S - bacteriostatic
blocks peptide transfer (translocation)
chloramphenicol clinical use
anaerobic (bact fragilis, c perf) infections in aspiration pneumonia or lung abscesses
oral infections with mouth anaerobes
treats anaerobes above the diaphragm
chloramphenicol
treats anaerobes below the diaphram
metronidazole
clindamycin toxicity
pseudomembranous colitis (c diff growth), fever, diarrhea