Antibiotic Mechanisms Flashcards
What are the classes of antibiotics that inhibit cell wall synthesis
- Penicilins
- Cephalosporins
- Carbapenems
- Monobactams
- Glycopeptides
- Lipoglycopeptides
How do Beta lactams differ from the glycopeptides and lipoglycopeptides with regards to cell wall synthesis
Beta lactams inhibit transpeptidase, while the peptides bind to cell wall precursors and prevent cell wall cross linking and extension
What are the antibacterial that bind to the 50s Ribosome
Oxazolidinones
Macrolides
Ketolides
Streptogramins
What are the antibacterials that bind to the 30s ribosomal subunit
Tetracyclines
Aminoglycosides
Glycylcyclines
Which class of drug inhibit DNA/RNA synthesis
Floroquinolones
What are the mechanism of action in flouroquinolones
Inhibiting topoisomerase 2 and 4
What is the mechanism of action for penicilins
Binds to transpeptidase and prevents the crosslinking in the cell wall
What kind of activity do penicilins have on bacteria
Bactericide,but only when the bacteria are replicating
Which group of bacteria are most susceptible to penicillin G
Gram positive bacteria
Gram negative cocci
Nonbeta lactamase anaerobes
Which bacteria are susceptible to aminopenicillins
Gram negative bacteria
Which group of bacteria are susceptible to penicillinase resistant penicillins
Staphylcoccal species
What about penicillinase resistant penicillins make it effective against staphylococcal species
Resistant to their penicillinase
Which bacteria in general and which specifically are susceptible to antipseudomonal penicillins
- Gram negative
- Pseudomonase aeruginosa
What is the only drug in the antipseudomonal penicillins clinically used
Piperacillin
Which drug is always cogiven with piperocilin
The betalactamase inhibator tazobactam
What is the antibacterial activity of beta lactamase inhibitaor
Very weak antibiotics,
Why are betalactamse inhibitors used
Paired with a beta lactam ringed antibiotic fo maximum effect
In general cephalosporins tend to work better on which trait in bacteria
Fast replicating
What is the mechanism of action for the cephalosporins
Beta lactam ring that binds to the transpeptidase binding protein
What is the relation of stability against many beta lactamases when compared to penicillins
More stable than penicillins
Which bacteria are more susceptible to first generation cephalosporins
Gram positive cocci
How effective are first generation cephalosporins on MRSA
Not very effective
What bacteria are susceptible to second generation cephalospoirins
Gram postive and some gram negative
What bacteria producing lactamases are second generation cephalosporins resistant to
Gram negative rods
What is the susceptibility of enterococci or P. Aeruginosa to second generation cephalosporins
Not susceptible
What is a side effect of Cefoteten
Hypoprothrombinemia and excess bleeding
Which bacteria are susceptible to third generation cephalosporins
Gram negative
What is the only drug in the third generation cephalosporin able to kil Pseudomonas
Ceftazidime
What bacteria are susceptible to fourth generation cephalosporins
Enterobacter and Pseudomonas
Which bacteria are susceptible to fifth generation cephalosporins
MRSA and pseudomonas
What is the mechanism of action for carbapenems
Beta lactam ring that block the transpeptidase in cell wall building
In the case of carbapenems, what mist be given with Imipenem
Renal dipeptidase inhibator Cell statin
What are the general targets for carbapenems
Gram negative bacteria
What is the mechanism of action for the monobactams
Monolytic beta lactam ring that inhibits gram negative transpeptidase
What are the target for monobactams
Gram negative only
What is the mechanism of action for glycopeptides and lipoglycopeptides
Bind to the D-ala-D-ala peptides so they are unable to be used in the building of the cell wall
Which bacteria tend to be more resistant to vancomycin
Gram negative bacilli and mycobacterium
What is the mechanism of action for the oxazolidinones
Binds to the P site of the 50S ribosome subunit, causing the inability of the fMET tRNA complex from forming
What are the targets for oxazolidinones
Gram positive
What is the mechanism of action for Macrolides and ketolides
Binds to the P site on the 50S ribosome
What is the mechanism of streptogramins
Work together by binding to the 50S ribosome, which prevents the elongation of the polypeptide chain
What are streptogramins used to target
Gram positive cocci
What bacteria are ineffected by streptogramins
Gram negative bacteria
What is the mechanism of action for tetracycline and glycylcines
Binds to the 30S ribosomal unit and prevented tRNA from entering the A site
What is the mechanism of action for aminoglycosides
- Lock AUG with the other ribosome subunits
- Immature stoppage of translation
- Introduction of errors into protein synthesis
What is the main target for aminoglycosides
Gram negative aerobic bacteria
What is the mechanism of action for flouroquinolones
Binds to topoisomerase and causes DNA coiling
Which bacteria are targeted by flouroquinolones
Gram negative bacteraia
What is the mechanism of action for sulfonamides
Analog of PABA to competitively inhibit dihydropteroate synthase
What is the mechanism of action for trimethoprim
Potent and selective inhibator of bacterial dihydrofolate reductase
What is the mechanism of overall action for Trimethoprim and sulfamethoxazole
Inhibition of bacteria ability to create folate and they work together
What is the mechanism of action for polymyxin
Amphipathic, so is able to insert itself into the outermembrane of gram negative bacteria, along with LPS
What is the target for polymixins
Gram negative aerobic bacteria
