Mechanisms of Action of Abs Flashcards
What is Pharmacokinetics?
Encompasses all the ways that the body manipulates a drug
What are the ways the body manipulates the drug?
Absorption
Distribution
Metabolism
Excretion
What is Pharmocodynamics?
Describes biochemical and physiological effects of the drug and its mechanism of action on the bacteria
What is a Bacteriostatic?
Antimicrobial agents that INHIBIT the growth/reproduction of the infecting agent
BUT do not actually kill it
What are some examples of Bacteriostatics? (6)
Ma-cro-lids --> (E-ry-thro-my-cin) Clin-da-my-cin Sulfa-me-thox-a-zole Tri-me-thro-pin Te-tra-cy-clins Chlo-ram-phe-ni-col
What is a Bacteriocidal?
Antimicrobial agent that is capable of causing IRREVERSIBLE damage/death to the organism
What are some ex of Bacteriocidals? (5)
Beta-lactam Abt –> (Penicillins and Ce-pha-la-sporins)
Va-co-my-cin
Amino-gly-co-sides –> (Gen-ta-my-cin)
Fluo-ro-qui-no-lones (Ci-pro-flox-a-cin)
What factor affects wether a drug exhibits bacterio -static or -cidal?
It is the antimicrobial concentration at the site of action
ATM may be -static at low [C], but -cidal at high [C]
What is Minimal Inhibitory Concentration?
Minimal amount of antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation
What are broad spectrum Ab?
One that is active against a wide range of bacteria (gram +/-)
Used priorly to ID’ing the causative bacteria
What are narrow spectrum Ab?
ACtive against a select group of baterial types
What are the FIVE mechanisms of action, that Abs use to inhibit or kill bacteria?
Interference with cell wall synthesis (MOST COMMON)
Interference with protein synthesis
Interference with cytoplasmic mem function
Interference with nucleic acid synthesis
Interference with metabolic PW
What do most agents in the “inhibitors of cell wall synthesis” interfere with?
Peptidoglycan synthesis and murein assembly
What agents are included in “inhibitors of cell wall synthesis”?
Beta-lactam Abs
Glycopeptides
What are the Beta-lactam ABs? (5)
Penicillins
Cephalosporins
Monobactams
Carbapenems
What is the mechanism of action of Beta-lactam Abs?
Bind at active site of the transpeptidase En that cross-links the peptidoglycan strands - IRREVERSIBLY inhibits En
–>Formation of cell wall is prevented
What are the four generations in cephalosporin?
Each generation exhibits increased spectrum of activity as well as increased RESISTANCE to destruction by
Beta-lactamase En’s
What are Monobactams active against?
Aerobin gram (-) BACILLI
What are Carbapenems active against?
All pathogenic organisms ans resistant to destruction by the extended spectrum B-lactamses (ESBL’s)
What are glycopeptides (vancomycin)?
They are another type of antimicrobials that interfere with cell wall synthesis
How are glycopeptides inhibitors of cell wall synthesis?
They act by BINDING to the D-alanyl-D-alanine residues – preventing the cross linking of the peptidoglycan sheets
EFFECTIVE ONLY AGAINST GRAM (+)
How is Fosfomycin an inhibitor of “cell wall” synthesis?
Inhibits phos-pho-enel pyruvate –> halting MURAMIC ACID synthesis (outside of acid-fast bacteria)
What are the 3 main mechanisms in which “agents of the inhibitors of protein synthesis” inhibit protein synthesis?
1- Interfere with the formation of the 30S initiation complex (mRNA, 30S, tRNA)
2- Interfere with the formation of the 70S ribosome (30S initiation complex and 50S ribosome)
3- Block elongation process of assembling A.A’s into polypeptides
What are the main agents in this group? (6)
Aminoglycosides Linezoid Macrolids Lincosamides Chloramphenicol Tetracyclines
