Micro AntiMicrobials Flashcards
Blocks cell wall synthesis by inhibiting peptidoglycan cross-linking
Penicillin, Methicillin, Ampicillin, Piperacillin, Cephalosporins, Aztreonam, Imipenem
Blocks peptidoglycan synthesis
Bacitracin, Vancomycin
Inhibits Folic Acid Synthesis (involved in methylation)
Sulfonamides, Trimethoprim
Blocks DNA topoisomerase
Fluoroquinolones
Blocks mRNA synthesis
Rifampin
Damages DNA
Metronidazole
Blocks protein synthesis at 50S ribosome
Chloramphenicol, Macrolides, Clindamycin, Streptogamins (Quinupristin, dalfopristin), Linezolid
Blocks protein synthesis at 30S ribosome
Aminoglycosides, Tetracycline
Penicillin Names? Class? MoA Use? Bactericidal for... Tox Resistance
G (IV and IM), V (oral). β-lactam Antibiotic
Binds PBP (transpeptidiases) and blocks its cross-linking of peptidoglycan
Gram+, N meningitidis, T pallidum, Syphilis
Bactericidal for Gram+ cocci, Gram+ rods, Gram- cocci, Spirochetes
Hypersensitivity rxn, Hemolytic anemia
β-lactamase cleaves β-lactam ring
Penicillinase-Resistent Penicillins Names Spectrum MoA Use Tox
Oxacillin, Nafcillin, Dicloxacillin
Narrow spectrum
Same as penicillin but bulk R group blocks β-lactamase access
S aureus (except MRSA)
Hypersensitivity reaction. Interstitial nephritis
Aminopenicillins Names? Spectrum? MoA Availability Use Tox Resistance
Ampicillin and Amoxicillin. Wide spectrum
Same as penicillin.
AmOxicillin has greater Oral availability
“HELPSS kill Enterococci “
H influenzae, E coli, Listeria, Proteus, Salmonella, Shigella, Enterococci
Hypersensitivity rxn, Ampicillin rash, Pseudomembranous colitis
Penicillinase sensitive. Combine w/ Clavulanic acid to protect against β-lactamase
Antipseudomonals Names MoA? Spectrum? Use Tox Resistance
Ticarcillin and Peperacillin Same as penicillin. Extended spectrum Pseudomonas and Gram- rods Hypersensitivity rxn Penicillinase. Use with Clavulanic acid
β-lactamase Inhibitors
“CAST”
Clavulanic Acid, Sulbactam, Tazobactam
Cephalosporins MoA Resistance What does it do to bacteria What bacteria can in kill? Tox
β-lactam
Less susceptible to penicillinase
Does not kill “LAME” bugs
Listeria, Atypicals (chlamydia, Mycoplasma, MRSA, Enterococci
Ceftaroline covers MRSA
Hypersensitivity, VitK deficiency. ↑ nephrotoxicity of aminoglycosides
1st gen Cephalosporins
Names
Uses
Cefazolin, Cephalexin
Gram+ cocci, Proteus, E coli, Klebsiella
“PEcK”
Cefazolin used prior to surgery to prevent S aureus wound infection
2nd gen Cephalosporins
Names
Uses
Cefoxitin, Cefaclor, Cefuroxime
Gram+ cocci, Haemophilus, Enterobacter aerogenes, Neisseria, Proteus, E coli, Klebsiella, Serratia
“HEN PEcKS”
3rd gen Cephalosporins
Names
Uses
Ceftriaxone, Cefotaxime, Ceftazidime
Serous Gram- infections resistant to other β-lactam
Ceftriazone: Meningitis and Gonorrhea
Ceftazidime: Pseudomonas
4th gen Cephalosporins
Names
Uses
Cefepime
Pseudomonas and Gram+
Aztreonam MoA Resistance Use Tox
Monobactam. Prevents peptidoglycan cross-linking by binding PBP3
Resistant to β-lactamase
Gram- rods only. No activity against Gram+ or anaerobes (pseudomonas)
Used for penicillin allergy pts and those with renal insufficiency who cannot tolerate aminoglycosides
Generally nontoxic. Possible GI upset.
Carbapenems Names MoA Co-administration w/... Resistance Use Tox
Imipenem, Meropenem, Ertapenem, Doripenem
Broad spectrum β-lactam.
I is coadministered w/ Cilastatin (inhibitor of renal dehydropeptidase I) to ↓ inactivation of drug in renal tubules. M resistent to inactivation
Resistent to β-lactamase
Gram+ cocci, Gram- rods, and anaerobes
Only used when all else fails or life threatening
GI distress, Skin rash, CNS tox (seizures)
Vancomycin MoA What does it do to bacteria? Use Tox Resistance
Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors
Bactericidal
Gram+ only. Multi-drug resistant organisms: MRSA, enterococci, C diff
“NOT so bad”
Nephrotoxic, Ototoxic, Thrombophlebitis (inflammation of a vein caused by a blood clot), Diffuse flushing - Red Man Syndrome (prevented by pretreatment with antihistamines and slow infusion rate)
Mutation of 2nd D-ala to D-lac
Protein Synthesis inhibitors
“Buy AT 30, CCEL (sell) at 50”
30S inhibitors:
Aminoglycosides (bactericidal), Tetracyclines (bacteristatic)
50S inhibitors (bacteristatic):
Chloramphenicol, Clindamycin, Erythromycin (macrolides), Linezolid (variable)
Aminoglycosides Names What does it do to bacteria? MoA Uptake
“Mean GNATS caNNOT kill Anaerobes”
Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin
Bactericidal
Inhibits formation of initiation complex and causes misreading. Blocks translocation
Needs O2 for uptake thus ineffective against anaerobes
Aminoglycosides
Use
Tox
Resistance
“Mean GNATS caNNOT kill Anaerobes”
Severe Gram- rods. Synergistic w/ β-lactams. N for bowel surgery
Nephrotoxic (esp w/ cephalosporins), Neuromuscular blockade, Ototoxic (esp w/ loops diuretics), Teratogen
Transferase enzyme that inactivates the drug by acetylation, phosphorylation or adenylation
Tetracylcines Names What does it do to bacteria? MoA Elimination Do not take w/
Tetracycline, Doxycycline, Demeclocycline, Minocycline
Bacteriostatic
Binds 30S and prevents attachment of aminoacyl-tRNA
Demeclocycline is an ADH antagonist used to treat SIADH
Doxycycline fecally eliminated so it can be given to pts with renal failure
Do not take with milk, antaacids, iron b. divalent cations inhibit gut absorption
Tetracylcines Use Tox Contraindications Resistance
Borrelia burgdorferi, M pneumoniae, Rickettsia, and Chlamydia (accumulates in cells so good at killing last 2)
GI distress, discoloration of teeth and inhibition of bone growth in children. Photosensitivity
Pregnancy
↓ Uptake or ↑ efflux by plasmid encoded pump
Macrolides Names What does it do to bacteria MoA Use
Azithromycin, Clarithromycin, Erythromycin Bacteriostatic Blocks translocation ("macroSLIDES"). Binds 23S rRNA of 50S ribosome Atypical pneumonia (Mycoplasma, Chlamydia, Legionella), STDs (Chlamydia), Gram+ cocci (strep in pts allergic to penicillin)
Macrolides
Tox
Resistance
“MACRO”
Motility issues, Arrhythmia (long QT), acute Cholestatic hepatitis, Rash, eOsinophilia. Increased serum concentration of theophyllines and oral anticoagulants
Methylation of 23S rRNA binding site
Chloramphenicol What does it do to bacteria? MoA Use Tox Resistance
Bacteriostatic. Blocks peptidyltransferase at 50S
Meningitis (Haemophilus, N meningitidis, Strep pneumoniae)
Anemia, Aplastic anemia, Gray baby syndrome (in premies b/c lack of UDP glucuronyl transferase)
Plasmid encoded acetyltransferase inactivates drug
Clindamycin What does it do to bacteria? MoA Use Tox
Bacteriostatic. Blocks peptide transfer (transpeptidation) at 50S ribosomal subunit
Anaerobes (Bacteroides fragilis, C perfringens) in aspiration pneumonia or lung abscesses. Oral infections with mouth anaerobes
“Anaerobes above the diaphragm”
Pseudomembranous colitis (C diff overgrowth), Fever, Diarrhea
Sulfonamides Names What does it do to bacteria? MoA Use Tox Resistance
Sulfamethoxazole (SMX), Sulfisoxazole, Sulfadiazine
Bacteriostatic
PABA antimetabolite inhibits dihydropteroate syntahse
Gram+, Gram-, Nocardia, Chlamydia, UTIs
Hypersensitivity, Hemolysis (G6PD deficiency), Nephrotoxic (tubulointerstitial nephritis), Photosensitivity, Kernicterus (infants), Displace other drugs from albumin (warfarin)
Altered dihydropteronate synthase, ↓ uptake, ↑ PABA synthesis
Bacterial DNA, RNA, and Protein Synthesis
PABA + Pteridine –> [Dihydropteroate Synthase] –> Dihydropteroic acid –> Dihydrofolic acid –> [Dihydrofolate reductase] –> THF –> N methylene THF –> Purines (DNA and RNA), Thymidine (DNA), and Methionine (proteins)