Term
Sulfonomides
1. Function
2. Bacteriostatic or Bacteriocidal?
2. Mechanism of resistance |
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Definition
1. Inhibits DNA synthesis. PABA analog that inhibits folic acid synthesis
2. Bacteriostatic
3. modification or complete substitution of Dihydropteroic acid synthetase |
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Term
Trimethoprim
1. Function
2. Bacteriostatic or Bacteriocidal?
3. Mechanism of resistance |
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Definition
1. Inhibits DNA synthesis. Inhibits dihydrofolate reductase, therefore inhibitting folic acid synthesis
2. Bacteriostatic
3. modification or complete substitution of Dihydrofolate reductase |
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Term
Rifampin
1. Mechanism of resistance |
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Definition
Inhibits DNA synthesis. Binds RNA polymerase to prevent transcription
1. Amino acid chagnes in RNA polymerase |
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Term
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Definition
| Inhibits DNA synthesis. It causes breaks in DNA |
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Term
Quinolones/Floroquinolones
1. Mechanism of resistance |
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Definition
Inhibits DNA synthesis. Inhibit DNA gyrase that prevents DNA relaxation for transcription
1. Efflux pumps, permeability mutations |
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Term
Aminoglycoside
1. How do they work?
2. What are the mechanisms of resistance
2. What bacteria do they affect/not affect? |
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Definition
1. Ribsome/Translation inhibitors. Aminoglycosides interact with the 16S rRNA in the 30S subunit of the ribosome, preventing the binding of f-Met (formyl-methionine), which is the 1st amino acid of most bacterial proteins.
2. Affects gram negative and gram positives but they need to respire. Requires strong PMF to get transported
Intestinal tract flora not affected
2. Aminoglycosides are inactivated by modification by the bacteria. There are 3 basic modifications that will inactivate Aminoglycosides:
N-acetylation
O-phosphorylation
O-adenylation |
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Term
| Oxazolidinones - Zyvox (Linezolid) |
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Definition
| Ribsome/Translation inhibitors. Oxazolidinones prevent formation of f-met:mRNA:30s subunit tertiary complex. Active against MRSA, VRE and multiresistant S. Pneumoniae |
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Term
Tetracycline
1. Mechanism of resistance |
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Definition
Ribsome/Translation inhibitors. Interact with the 16srRNA portion of the 30s ribosomal subunit and block the transfer of tRNA into the acceptor site
1. Efflux pumps |
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Term
Chloramphenicol
1. Mechanism of resistance |
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Definition
Ribsome/Translation inhibitors. Interact with the 50s subunit and block the formation of the peptide bond.
1. Acetylation of the drug |
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Term
Lincosamides
1. Mechanism of resistance |
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Definition
Ribsome/Translation inhibitors. Interact with the 50s subunit and block the formation of the peptide bond.
1. An erthromycin methyltransferase gene that methylates 23S rRNA prevent interaction of macrolides and lincosamides/clindamycin with the 23S rRNA and the 50S ribosomal subunit |
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Term
Macrolides (Erythromycin)
1. Mechanism of resistance |
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Definition
Ribsome/Translation inhibitors. Interact with the 23S rRNA in the 50s subunit and cause the release of the growing peptide chain
1. An erthromycin methyltransferase gene that methylates 23S rRNA prevent interaction of macrolides and lincosamides/clindamycin with the 23S rRNA and the 50S ribosomal subunit |
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Term
Streptogramins
1. Mechanism of resistance |
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Definition
Ribsome/Translation inhibitors. Bind 50s subunit and block translocation of the peptide chain to the E(P) site.
1. Amino acid mutations of the 50s subunit |
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Term
Phosphomycin
1. Mechanism of resistance |
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Definition
Inhibits Cell wall synthesis. Phosphomycin/Fosfomycin is a PEP analog that inhibits the synthesis of NAM from NAG.
1. Phosphomycin is cleaved by fosfomycinases |
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Term
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Definition
Inhibits Cell wall synthesis.
D-cycloserine is an analog of D-Ala and inhibits the racemase reaction and addition of D-Ala to the AA1-AA2-AA3 chain |
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Term
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Definition
| Inhibits Cell wall synthesis. Bacitracin binds undecaprenyl-PP and inhibits recycling of the carrier. |
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Term
Vancomycin
1. Mechanism of Resistance |
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Definition
Inhibits Cell wall synthesis.
Vancomycin (glycopeptide antibiotic) binds D-Ala-D-Ala and sterically hinders PBPs from carrying out transpeptidation and transglycosylation reactions.
1. genes change the D-Ala-D-Ala pentapeptide to D-Ala-D-Ser or D-Ala-D-Lac |
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Term
B-lactams
1. What are the mechanisms of resistance |
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Definition
Inhibits cell wall synthesis
B-lactams are structurally related to D-Ala and tightly bind PBPs inhibiting their transglycosylation and transpeptidation activity.
1. Protein b-lactamase cleaves the b-lactam ring. There are extended spectrum b-lactamases as well. |
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Term
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Definition
Cell membrane antibiotic.
Disrupts bacterial membrane causing release of cytoplasmic components
will destroy dormant (non-replicating) cells
Only given topically as it will kill eukaryotic cells. |
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Term
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Definition
Cell membrane antibiotic.
class of antibiotics that self-assemble to form pores in membranes. ie. Nisin.
Not approved for human treatment |
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Term
| Beta-Lactamase inhibitors |
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Definition
-lactamase inhibitors can be co-administered with penicillin.
These have a reduced rate of cleavage causing the beta-lactamase to be less efficient |
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