Antibiotics 1 Flashcards
1st MOA of Antibiotics: Inhibition of cell wall synthesis
Bind to cytoplasmic-protein-binding proteins (PBPs) –> inhibit transpeptidation –> inhibit cross-linking of bacterial cell wall
1st MOA of Antibiotics: Inhibition of cell wall synthesis - Buzzword (6)
Penicillins
Cephalosporins
Imipenam
Meropenem
Aztreonam
Vancomycin: inhibits peptidoglycan synthase binds to D-Alanine
2nd MOA of Antibiotics: A - Interfere with the formation of initiation complex: Buzzword (2)
Aminoglycoside (30S)
Linezolid (50S)
2nd MOA of Antibiotics: A - Interfere with the formation of initiation complex: How is it a bactericidal?
Misread of genetic code carried by mRNA –> incorporation of wrong amino acid
2nd MOA of Antibiotics: B - Interfere with incorporation of next amino acid: Buzzword (2)
Tetracyclines (30S)
Dalfospristin & Quinupristin (50S)
2nd MOA of Antibiotics: B - Interfere with incorporation of next amino acid: How is it a bacteriostatic?
Inhibit the insertion of aminoacyl t-RNA into “A” site
2nd MOA of Antibiotics: C - Interfere with formation of peptide bond Buzzword and how is it a bacteriostatic? (2)
Chloramphenicol
Bacteriostatic by inhibition of peptidyltransferase
2nd MOA of Antibiotics: D - Interefere with Translocation Buzzword and how is it a bacteriostatic? (3)
Macrolide (50S)
Clindamycin (50S)
Bacteriostatic by inhibiting translocation of peptidyl-tRNA from acceptor to donor site
Inhibitors of Bacterial Protein Synthesis: Drugs that affect the 30S ribosomal subunit - Aminoglycosides (4)
- Gentamicin
- Neomycin
- Streptomycin
- Spectinomycin
Inhibitors of Bacterial Protein Synthesis: Drugs that affect the 30S ribosomal subunit - Tetracyclines (4)
- Doxycycline
- Minocycline
- Tetracycline
- Tigecycline
Inhibitors of Bacterial Protein Synthesis: Drugs that affect the 50S ribosomal subunit - Macrolide and Ketolide Antibiotics (4)
- Azithromycin
- Clarithromycin
- Erythromycin
- Telithromycin
Inhibitors of Bacterial Protein Synthesis: Other Antibiotics binding the 50s subunit (3)
- Chloramphenicol
- Clindamycin
- Quinupristin-Dalfopristin
Inhibitors of Bacterial Protein Synthesis: Other Protein Synthesis Inhibitors (2)
- Mupirocin
2. Linezolid
3rd MOA of Antibiotics: Inhibition of Folic Acid Synthesis - Buzzword 1 (2)
Sulfonamide
Inhibits dihydropteroate synthetase
3rd MOA of Antibiotics: Inhibition of Folic Acid Synthesis - Buzzword 2
Trimethoprim and Pyrimethamine
Inhibits dihydrofolate reductase
4th MOA of Antibiotics: Inhibtion of Nucleic Acid Synthesis Buzzword 1 (2)
Fluroquinolones
Inhibit DNA gyrase (Topoisomerase II)
4th MOA of Antibiotics: Inhibtion of Nucleic Acid Synthesis Buzzword 2 (2)
Rifampin
Inhibits DNA-dependant RNA polymerase
Mechanism of Resistance: Beta-lactamase cleavage of drugs B-lactam ring Buzzword (2)
- Penicillins
2. Cephalosporins
Mechanism of Resistance: Production of conjugating enzymes that increase drug clearance Buzzword (1)
Aminoglycosides
Mechanism of Resistance: Formation of acetylating enzymes that inactivate drugs Buzzword (1)
Chloramphenicol
Mechanism of Resistance: Methylation of base in RNA that alter drugs binding Buzzword(1)
Macrolides
Mechanism of Resistance: Production of active transport systems that push drugs out of the cell Buzzword (1)
Tetracyclines
Mechanism of Resistance: Formation of PABA, increase resistance to inhibiton of dihydropteroate synthetase Buzzword (1)
Sulfonamides
Mechanism of Resistance: Increase transport systems to push drugs out and increase resistance to inhibition of topoisomerase II Buzzword
Fluoroquinolonees
Antibiotic Resistance
R-factor plasmid-mediated transmission
Selection of resistant cells
Antibiotics Combination: Additive Effect
1 + 1 = 2
Antibiotics Combination: Synergistic Effect
1 + 1 = 3
Penicillins + Aminoglycosides
Antibiotics Combination: Antagonistic Effect
1 + 1 = 0
Penicillin + Tetracyclines in pneumococcal meningitis
Antibiotics Combination: Clinically (2)
Bacteriostatic: Active host defense dependant
Bacteriocidal: immunocompromised
Antibiotics Combination: Examples of conditions (1)
H. Pylori
Bacteria: Gram +ve (Purple) (3)
- Staphylococcus
- Streptococcus
- Clostridium
- Staphylococcus
Bacteria: Gram -ve (Pink/Red) (5)
- E. Coli
- Neisseria
* 3. Pseudomonas - Bacteroids
- Klebsiella
Staph Aureus (G+): Types (4)
- Non-penicillinase Producing
- Penicillinase Producing
- Methicillin Resistant Staph Aureus (MRSA)
- Vancomycin Resistant Staph Aureus (VRSA)
Antibiotics Story: 1
First (1): It penicillins: good against Gram +ve –> Strep and Staph
Buzz word: Pencillin VK (Oral) and Penicillin G (IV-IM)
Antibiotics Story: 2
Some penicillanase producing staph aureus appeared so they came up with
- Penicillin resistant penicillins (5):
- Oxacillin (IV)
- Cloxacillin (PO)
- Dicloxacillin (PO)
- Nafcillin (IV)
(Ox/Clox/Diclox/Naf) - Methicillin (only used in lab)
Good against staph aureus
Staph Aureus (G+): MRSA Buzzword
VANCOMYCIN
Vancomycin is NOT A PENICILLIN
Antibiotics Story: 3 - Broad Spectrum Antibiotics (Aminopenicillins) Buzzword and Use
Buzzword: Amoxicillin and Ampicillin
Good against:
Strep
G-ve bacteria
BUT NOT STAPH AUREUS
Antibiotics Story: 4 - Extended Spectrum Penicillins (antipseudomonads) Buzzwords, Use, and Solution for Staph
Buzzword: Piperacillin - Ticarcillin - Carbenicillin
Good against:
Strep
G-ve (*Including psedumonas)
NOT STAPH AUREUS
Since broad and extended spectrum didn’t cover staph aureus, what did they do?
Came up with Beta-lactamase inhibitors
Buzzword: Clavulanate and Sulbuctam
and combined it with broad and extended spectrum to cover everything including staph aureus
Drugs good against G+ve and G-ve BUT NOT MRSA (4 pairs)
- Amoxacillin/Clavulanate (sinusitis, strep throat, acute pharyngitis)
- Ampicillin/Sulbactum
- Pipercilin/Tazobactam (pseudomonas
- Ticarcillin/Calvulunate
1st Caution with Antibiotics
Always, always, always assess for allergies
2nd Caution with Antibiotics
If allergic to penicillin, they’ re also allergic to cephalosporins
3rd Caution with Antibiotics
If normal flora is disturbed during antibiotic therapy –> superinfection caused by microorganisms resistant to the given antibiotics
Signs of superinfections
Black, furry overgrowth on the tongue
Loose or foul smelling stools
Vaginal itching or discharge in women
4th Caution with Antibiotics
Avoid taking oral penicillin and acidic juices or soda
Why? It reduces drug absorption
5th Caution with Antibiotics and buzzwords for bacterial resistance
Always, always, always teach the patient about completeing the full therapeutic course, even if they’re feeling better
Why? Risk for resistant organism
Buzzwords for bacterial resistance
- Patient stops takes antibiotics
- Environmental disperion of liquid antibiotics
- Antibiotics are prescribed to Rx viral infection
Cephalosporins: 1st Generation of 5 and Buzzword
Good against G+ve
Cefazolin: Surgical prophylaxis
Cephalothin: Renal tubular necrosis
N CNS entry
Cephalosporins: 2nd Generation of 5 and buzzwords
Good against G-ve
No CNS entry EXCEPT CEFUROXIME
Cefotetan: Rx for bacteroid fragilis (disulfiram like action)
Cefaclor: some serum sickness
Cephalosporins: 3rd Generation of 5 and buzzwords
Good against G-ve and Pseudomonas
Enter CNS except cefoperazone*
*Side effects: Pseudomembranous colitis
Ceftriaxone IV single dose for gonorrhea
Cefixime (PO)
Cephalosporins: 3rd Generation of 5 - Rx for biliary sludge with cholecystitis like illness (2)
- Ceftriaxone
2. Cefoperazone
Cephalosporins: 4th Generation of 5 and Drug
Good against G+ve
As good as third
Cefepime IV
Cephalosporins: 5th Generation of 5 (2)
- Ceftaroline: High affinity for PBP2a in oxacillin resistant staphylococci
- GOOD AGAINST MRSA)
- Ceftobiprole:
GOOD AGAINST MRSA and PENICILLIN RESISTANT STREPTOCOCCI
Cephalosporins: Dose adjustment in renal impairment except? (2)
Ceftriaxone
Cefoperazone
Cephalosporins: If patient is allergic to penicillins?
Don’t prescribe cephalosporins
If G+ve: use Macrolides
If G-ve: use Aztreonam
Cephalosporins: Are not effective against? (5)
- Chlamydia
- Mycoplasma
- Listeria
- MRSA
- Enterococci
Bacitracin (3)
Derived from a bacillis subtilis
Inhibits cell wall peptidoglycan by blocking bactoprenol
Used topically for infections caused by G+ve cocci
Fosfomycin (2)
Blocks the formation of UDP-MurNAc (UDP-N-acetylmuramic acid), a first step in cell wall peptidoglycan synthesis
Single dose for uncomplicated UTI
Augmentin (Amox/Clav) is good for?
Skin lesions when cause is unknown