Antibiotics/Antifungals/Antivirals Flashcards
Cell wall inhibitors
Penicillins
Cephalosporins
Carbapenems
Vancomycin
Bacitracin
Fosfomycin
Isoniazid
Acts on cell membrane
Polymyxins
Daptomycin
Antibiotics that inhibits DNA replication and transcription
Quinolones
Inhibits RNA polymerase
Rifampin
Acts on 50S subunit
Erythromycin
Clindamycin
Synercid
Pleuromutilins
Acts on 30S subunit
Aminoglycosides - gentamycin, streptomycin
Tetracycline
Glycylcyclines
Acts on both 30S and 50S
Linezolid
Acts on folic acid synthesis in cytoplasm
Sulfonamides
Trimethoprim
Mechanism of action of meropenem
Binds penicillin binding protein to inhibit cell wall synthesis
Mechanism of action of ciprofloxacin
Inhibits DNA topoisomerase
Mechanism of action of trimethoprim
Disruption of dihydrofolate reductase
Mechanism of action of erythromycin
Inhibition of translocation of tRNA at 50S ribosomal subunit
Mechanism of action of rifampicin
Inhibits DNA-dependent RNA-polymerase
Mechanism of action of colistin
Disruption of cell membrane via LPS and phospholipids
Mechanism of action of sulfamethoxazole
Inhibition of de novo folate biosynthesis
Mechanism of action of doxycycline
Competition with A site on 50S ribosomal subunit
Mechanism of resistance of VRE
Modification of drug target
van gene
Mechanism of aminoglycoside E. coli resistance
Enzymatic alterations of binding site
Mechanism of ESBL
Beta lactamases
Destruction of antibiotics
Mechanism of staph aureus with intermediate sensitivity to vancomycin
Global cell adaptation to antibiotic effects
Mechanism of action of entecavir
Guanosine analogue phosphorylated within virally infected cells into triphosphate that then incorporates into viral DNA - halts replication process
Mechanism of action of famciclovir
Guanosine derivative phosphorylated within virally infected cells to triphosphate that inhibits DNA polymerase
Mechanism of action of ritonavir
Inhibition of viral protease
Virus associated Kaposi’s sarcoma
HHV-8
Virus associated with Merkel cell carcinoma
Polyomavirus
Virus associated with primary CNS lymphoma
EBV
Virus associated with squamous cell anal cancer
HPV
Mechanism of action of echinocandins
Inhibits B-1, 3-D-glucan synthesis
Mechanism of action of polyenes (amphotericin B, nystatin)
Bind to membrane ergosterol, altering membrane integrity
Mechanism of imidazoles (ketoconazole) and triazoles (fluconazole, itraconazole)
Inhibits CYP450 enzyme lanosterol14 demethylase, results in decreased ergosterol production
Mechanism of action of terbinafine
Inhibits squalene epoxidase with resultant decrease in lanosterol and ergosterol production
Mechanism of action of griseofulvin
Inhibits fungal mitosis by binding to intracellular microtubular protein
Mechanism of action of 5-flucytosine
Converted to 5-fluorouracil, incorporated into fungal RNA inhibiting protein synthesis
Mechanism of action of B lactams
Binds to penicillin-binding-proteins –> decreases crosslinking of peptidoglycan layer
Examples of B lactam
Penicillin
Cephalosporins
Carbapenems
Monobactams
Generations of beta lactams
1st - cephalexin
2nd - cefaclor
3rd - cefixime
4th - cefepime
5th - ceftaroline
Mechanism of resistance for beta lactams
Cleavage of beta lactam ring by beta-lactamases
Mechanism of resistance for MRSA
PBP mutations
Mechanism of action for glycopeptides e.g. vancomycin, teicoplanin
Bind to D-alanyl-D-alanine section of peptidoglycan precursor –> inhibited peptidoglycan synthesis
Mechanism of resistance of vancomycin
Reduced penetration in gram negative bacteria
Change in peptidoglycan precursor structure
Mechanism of action for fosfomycin
Inactivate enolpyruvate transferase –> inhibition of N-acetylmuramic acid formation –> disruption of peptidoglycan synthesis
Adverse effects of carbapenems
Secondary fungal infections
CNS toxicity - highest risks of imipenem
GI upset
Rash Thrombophlebitis
Adverse effects of cephalosporins
Potential cross-reactivity in pts with penicillin allergies
AIHA
Vitamin K deficiency
Disulfiram-like reaction
Increases nephrotoxic effect of aminoglycosides
Neurotoxicity
Mechanism of action of aminoglycosides
Inhibits protein synthesis - 30S ribosomal subunit
Mechanism of resistance of aminoglycosides
Inactivating enzymes e.g. acetylation, phosphorylation, adenylation
Removal by efflux pumps
Mutation of bacterial ribosome binding site
Reduced penetrance
Anaerobic bacteria
Acidic environment
Mechanism of action of tetracycline
Inhibition of protein synthesis - 30S ribosomal subunit
Block incoming aminoacyl-tRNA with amino acids –> decrease protein synthesis
Mechanism of resistance of tetracycline
Reduced cell wall penetration
Removal by efflux pump
Production of protein that protects ribosome
Clinical use of daptomycin
Gram positive bacteria
S. aureus especially MRSA
VRE
Adverse effects of daptomycin
Reversible myopathy
Rhabdomyolysis
Allergic pneumonitis
Clinical use of colistin
Polymyxin
Severe gram negative bacteria that are multidrug resistant