antibacterial agents overview ppt Flashcards
Antibiotics eliminated by non renal functions (D-CRIMES)
Doxycycline
Clindamycin
Rifampin- inducer of P450 hepatotoxicity
isoniazid- genetic polymorphism hepatotoxicity
Metronidazole- drug to drug interaction with alcohol due to inhibition of aldehyde metabolism
Erythromycin- inhibition of P450
Sulfonamides- risk of renal crystalluria
Mechanisms of antibacterial drugs
- Cell wall synthesis
- DNA
- DNA gyrase
- Folic acid metabolism
- Protein synthesis inhibitors 50s and 30s
- Protein synthesis
- Cell membrane
- DNA-directed RNA polymerase
Cell membrane attacking antibacterial drugs
Polymyxins
Daptomycin
Folic acid metabolism mechanism drugs
Trimethoprim
sulfonamides
cell wall synthesis mechanism drugs
vanco
penicillins V and G, amoxicillin, ampicillin, pipercillin tazo
cephalosporins (cephalexin, cefazolin 1st gen), Cefuroxime 2nd gen, ceftriaxone 3rd)
DNA mechanism drugs
metronidazole
nitrofurantoin
Fluoroquinolones (cipro, levo, moxiflo)
DNA gyrase mechanism
quinolones
DNA-directed RNA polymerase mechanism drugs
rifampin
protein synthesis 50s inhibitors
Macrolides (eryhtromycin), azithromycin
clindamycin
protein synthesis 30s inhibitors
tetracycline (doxy and tetracycline)
streptomycin
tobramycin (aminoglycosides)
amikacin
Mechanisms of resistance
- decreased entry
- efflux pump
- bypass pathway
- enzymatic degradation
- altered target site
MRSA, S. pneumoniae and enterococci use Antibiotic target site alteration resistance mechanisms to which antibiotics?
B-lactam antibiotics (penicillins, cephalosporins, carbapenems)
S. aureus, Pseudomonas species use Antibiotic target site alteration resistance mechanisms to which antibiotics?
Fluoroquinolones
Enterococci, staphylococci use Antibiotic target site alteration resistance mechanisms to which antibiotics?
Vancomycin
Streptococci, staphylococci and enterococci use Antibiotic target site alteration resistance mechanisms to which antibiotics?
erythromycin, clindamycin
S. aureus, P aeruginosa, bacteroides and enterococci use antibiotic modification or inactivation resistant mechanisms against which antibiotics?
B-lactams ( penicillins and cephalosporins)
Enterococci alone uses acetyl-phospho-adenylyl transferases modification or inactivation against which antibiotic?
aminoglycosides
Pseudomonas aeruginosa uses decreased entry (natural resistance to which antibiotic?
B-lactam antibiotics
Pseudomonas species in general use decreased entry (natural resistance to which antibiotic?
Fluoroquinolones
E.coli, pseudomonas decreased entry (natural resistance to which antibiotic?
Aminoglycosides
Streptococci, staphylococci and enterococci use increased efflux resistance to which antibiotics?
Tetracyclines, Macrolides (was a question on his powerpoint)
Pseudomonas species use use increased efflux resistance to which antibiotics?
Fluoroquinolones
Mechanisms of bactericidal drugs
- inhibition of cell wall synthesis
- Disruption of cell membrane function
- interference with DNA function or synthesis
mechanisms of bacteriostatic drugs
- inhibition of protein synthesis
2. Inhibition of intermediary metabolic pathways
What are the gram positive cocci
Streptococci (pneumonia, pyogenes)
Staphylococci (aureus: MSSA-MRSA)
Enterococci
What are the gram negative cocci
Neisseria (meningitidis, gonorrhoeae), M. Catarrhalis
Rods: gram (-) and (+)
Gram (-): E. coli, pseudomonas aeruginosa, H. Influ)
Gram (+): Listeria
Anaerobes gram (-) and (+)
Gram (+): Clostridium difficile, H. Pylori
Gram (-): Bacteroides fragilis
Atypical organisms?
Chlamydia
Mycoplasma
Rickettsia
describe narrow spectrum I.E what are they effective against
either gram negative or gram positive
describe extended spectrum?
effective against gram positive and negative organisms
describe broad spectrum agents?
effective against gram positive and negative and atypical
What is concentration dependent killing?
Some antibiotics kill bacteria faster in doses that result in high initial Cp levels-can be dosed less frequently
What is time dependent killing?
Kill best when Cp is above MIC for longer durations
Beta-lactams
Vancomycin
Macrolides
What is post antibiotic effect and which antibiotics do this?
Persistent supression of bacterial growth after a brief exposure (1 to 2 hours) of bacteria to an antibiotic
Aminoglycosides, Fluoroquinilones, macrolides, beta-lactams
What are the narrow spectrum antibiotics
Aminoglycosides Penicillins-resistant penicillins Clindamycin Vancomycin Metronidazole Penicillin G, V
What are extended spectrum antibiotics?
Extended spectrum penicillins
Cephalosporins
Fluoroquinolones
Carbapenems
What are broad spectrum antibiotics
Macrolides Chloramphenicol Fluoroquinolones (moxi, Gemi) Sulfonamides tetracyclines Trimethoprim
Out of narrow, broad and extended which are most effective?
Narrow spectrum
