Flashcards in Antibiotics Deck (50):
Cell Wall Antibiotics
Protein Synthesis Inhibitors
Aminoglycosides (Tobramycin, Amikacin, Gentamycin)
Macrolides (Azithromycin, Clarithromycin, Erythromycin)
Nucleic Acid Inhibitors
Metronidazole (DNA Damage)
Beta Lactam Category
Beta Lactam Mechanism
Inhibition of bacterial cell wall synthesis by acylating transpeptidases
Mechanism of Resistance: B-lactamase inhibitors
Side Effects of Beta Lactams
Generally well tolerated unless patient is hypersensitive/allergic and then can lead to rashes, fever and other bad things
- Only effects gram + bacteria
- Inhibits cell wall synthesis (binds D-Ala-D-Ala terminus of pentapeptide
Resistance to Glycopeptics
Substrate modification (D-ala-D-ala to D-ala-D-lactate) through VanA transposon
Side Effects of Glycopeptics
10% of all cases
- Tissue irritation, chills, fever
- Ototoxicity and Nephrotoxicity
Tetracyclines include ...
Tetracyclines work by ...
inhibiting protein synthesis. Bind irreversibly to the 30S subunit of the bacterial ribosome. Blocks the aminoacyl-tRNA to acceptor site on mRNA-ribosome complex
Impaired influx or increased efflux by active transport protein
Ribosome protection via interfering proteins
Tetracyclines side effects
GI - nausea, vomiting, diarrhea
Bony structures - can be deposited in bones of growing fetus
Renal Tubular Acidosis
Hepatic function impairment in patients with hepatic issues
Aminoglycosides include ...
Aminoglycosides work by ...
Irreversibly inhibiting protein synthesis by binding the 30S. Interfers with the initiation complex, misreading of mRNA, breaks up polysome into nonfunctional monosomes
- production of transferase enzyme (inactivates Aminoglycosides)
- Impaired entry (porin protein mutation)
- Receptor protein on 30S is deleted or altered
Aminoglycosides side effects
Increase when drug is taken for more than 5 days!
Macrolides include ...
Macrolides works by ...
Inihibtion of protein synthesis by binding the 50S subunit (blocks exit channel)
Most effective against gram positive bacteria
- Reduced permeability
- Production of Esterases that hydrolyze macrolides
- Ribosomal protection via inhibitory proteins
Macrolides Side Effects
Anorexia, nausea, vomiting, diarrhea
Erythromycin --> Acute cholestatic hepatitis and inhibits cytochrome p450
Linezolid works by ...
preventing bacterial protein synthesis by binding to 23S ribosomal RNA of the 50S subunit. Bacteriostatic
primarily due to efflux pumps
Linezolid side effects
Hematogenic - duration-dependent bone marrow suppression, neuropathy, and optic neuritis
Flouroquinolones include ...
Ciprofaxin, levofloaxin, moxifloaxin
Flouroquinolones works on ..
both gram positive and negative
Flouroquinolones works by ...
Inhibiting topoisomerase II (DNA gyrase) and topoisomerase IV
Interferes with transcription (II), translation (II), and chromosome segregation during mitosis (IV)
Flouroquinolone side effects
Generally well tolerated
Contraindicated for patients with QTc interval prolongation
May damage cartilage (not usually recommended <18)
Metronidazole used for ...
ANAEROBIC bacteria!!! C. Diff colitis
Metronidazole works by ...
Disturbing ETC, reduced by ferredoxin, results in products that are toxic to anaerobic cells
usually combined with inhibitor of dihydrofolate reductase (trimethoprim) for UTI
Metronidazole side effects
Nausea, diarrhea, stomatitis, peripheral neuropathy
AVOID ALCOHOL ... ADH inhibitor
Sulfonamides work on ..
Gram positive and negative
Sulfonamides work by ..
antifolate, many bacteria cannot use exogenous folate, must synthesize it from PABA and Sulfonamidesare PABA analogs
- Overproduction of PABA
- Production of different enzymes w/ low Sulfonamide affinity
- Impair permeability
Sulfonamide Side Effects
Megablastic Anemia, Leukopenia, Granulocytopenia
Nausea, Vomiting , Fever
Vasculitis, renal damage, CNS disturbance
Most active drug for TB treatment
Isoniazid works by ...
- Inhibits my colic acid synthesis, an essential component of the cell wall
- Forms covalent bond with acyl carrier protein
Caused by over expression of inna gene, which encodes an NADH-dependent acyl carrier protein reductase
*Occurs often so a combination therapy is required
Isoniazid side effects
Hepatotoxic - may cause hepatitis.
Peripheral Neuropathy (give pyridoxine to prevent)
Used in conjunction with isoniazid
Rifampin works on ....
Both gram + and -
Rifampin works by ...
Binding beta subunit of bacterial RNA polymerase. Bactericidal for mycobacteria
Point mutations in rpoB, the gene for B subunit of the RNA polymerase
Rifampin side effects
- Rashes, thrombocytopenia, nephritis
Strong induction of cyto p450 and thus increases rate of elimination of drugs
Used in conjunction to isoniazid and rifampin