Antibiotics MOA
Terms
undefined, object
copy deck
- Penicillin
- Inactivate bacterial transpeptidases and prevent cross-linking of peptidoglycan polymers to interrupt cell-wall integrity; Gram pos bacteria with thick external cell walls are more susceptible
- Vancomycin
- inhibits cell wall synthesis. Tricyclic glycopeptide that binds to terminal end of growing peptidoglycan, preventing further elongation adn cross-linking.; Gram + organisms; penetrates CSF only during inflammation
- 2nd generation cephalosporins
- cefuroxime, cefoxitin, cefaclor; Spectrum extended to include H. flu and indole-positive Proteus. Less active against gram + than 1st geneartions
- Primaxin
- Imipenem/Cilastin; cell wall inhibitor/inhibitor of renal dehydropeptidase I (that inactivates imipenem); Broad spectrum, including S. aureus, E. coli, Klebsiella, Enterobacter and H.flu.
- Nafcillin
- Also disrupts cell wall formation, but is resistant to beta-lactamase; gram pos cocci, better for beta-lactamase producing staph infx.
- 3rd generation cephalosporins
- cefotaxime, ceftazidime, cefotetan, ceftriaxone; reduced activity against gram+ organisms, but enhanced activity against H.flu, N.gonorrhea, enterobacter, salmonella, serratia, indole-pos proteus; also, improved CSF penetration
- Augmentin
-
amoxicillin + clavulanic acid; Clav. acid irreversibly inhibits beta lactamase
- Erythromycin
- Macrolide inhibits protein synthesis by binding irreversibly to the bacterial 50S ribosomal subunit to terminate protein synthesis. Gram pos. , Legionella, Mycpolasmaaa, pertussis
- Aminoglycosides
- Inhibit bacterial protein synthesis. Interact with receptor proteins on the 30S ribosomal subunit. Are polycations that require active uptake, so gram neg aerobes only...enterobacter, Pseudomonas, Klebsiella, Serratia, Proteus
- Tetracyclines
- Bind to the 30S subunit and prevent binding of tRNA to the acceptor site on the mRNA-ribosome complex, inibitins bacterial protein synthesis. Active against gram neg and pos organisms, but use is declining. Mostly for Rickettsial infx
- Sulfonamides
- Prevent the synthesis of dihydrofolic acid. Competes with PABA for dihydropteroate synthetase. Inhibit both gram neg and gram pos organisms.
- Trimethoprim
- Inhibits dihydrofolate reductase. Used in combination with sulfamethoxazole
- Rifmapin
- Inhibits bacterial DNA-dependent RNA polymerase by binding to the beta subunit of the polymerase. Most gram pos organisms
- Aztreonam
- naturally occuring monobactam, also transpeptidase inhibitor. Activity against gram neg but none for gram positive or anaerobes.
- Nitrofurantoin
- Causes bacterial DNA damage by unknown mechanism. Bacteriostatic. Used soley as a urinary tract antiseptic against E.coli
- Quinolones
- Inhibit the nicking and closing action of bacterial DNA gyrase during bacterial DNA replication and growth. Concentrated in urine, therefore used as urinary tract antiseptics
- 4-Quinolone derivatives
- flourinated derivatives of nalidixic acid. Inhibit bacterial DNA gyrase (topoisomerase II) Gram neg are more sensitive than gram pos.
- Isoniazid
- Inhibits cell wall synthesis in mycobacteria. Most active drug against M. tuberculosis and M. kansasii
- 1st Generation Cephalosporins
- cephalothin, cephalexin, cefazolin; as with pcn, disrupts cell wall; good activity agains most gram pos and some gram neg (E. coli and klebsiella)