Chapter 20 Flashcards
Chemotherapy
A drug that is used to kill highly prolific cells in the body
antibiotic
Used to either kill or inhibit bacteria in the body
aminoglycosides
A toxic bactericidal antibiotic
Toxicity and its relation to therapeutic index / toxic doses
Toxicity is a relative term and is usually scaled. The therapeutic index is what is used to calculate the toxicity of a specific drug prior to pt administration.
The higher the therapeutic window=more toxic and increased pt harm
The lower the therapeutic window = less toxic and decreasedpt harm
antibiogram
A list of antimicrobial susceptibility testing results of a specific microbe to a numerous amt of antimicrobial drugs
Allergy
An immune response in which the body attacks potential threats w/ antigen-antibody complexes
Microflora
The microbiome that exist inside the intestine that help w/ digestion
Bacteriostatic v Bactericidal
Bacteriostatic: Inhibits bacteria (less toxic)br
Bactericidal: Kills bacteria (more toxic)
Broad Spectrum v Narrow Spectrum
Broad Spectrum: Affects a wide range of different bacteria including the native flora
Narrow Spectrum: Only affects specific bacteria and requires testing before administration. Not as disruptive to the native flora
Selective toxicity
Causes greater harm to microbes than the host
Plasma v Serum
Plasma:Liquid that remains when blood does not clot and is spun down
Serum: Liquid that remains when blood clots and is spun down
Through level v Peak level
Through Level: Measured before next drug administration
Peak Level: measured 2 hrs after drug administration
What is the difference in dosage between a medication w/ a longer half life as opposed to something w/ a shorter half life?
The longer the half life the smaller the dose, and the shorter the half life the bigger the dose
What are the 5 mechanisms of antibacterials?
Cell wall synthesis
protein synthesis
metabolic pathways
nucleic acid synthesis
cellular membrane
1st line v 2nd line drugs
1st line drugs are less toxic and are the most effective in killing bacteria
2nd Line drugs are more toxic and are les effective. These are only given when 1st line fails
What is a C&S exam?
An test that a doctor requests to determine the identity of a microbe and what medications its susceptible too.
Who discovered penicillin?
Flemming, However he gave up after a while because he could not sequester a pure sample to study
How can medications that are too toxic to be used internally administered?
They are are applied to the skin.
Small v Large window
If a medication has a smaller widow, that means that it becomes toxic quickly and in smaller doses. If it has a larger window it does not become toxic fast and can be given in larger doses.
What is a half life and why is it important to consider when giving medications?
A half life is the amount of time it takes a medication to be reduced by half in the body. This is important to consider, because it determines dosing. If a medication has a shorter half life it needs to be given more frequently. If it has a longer half life then it needs to be given less frequently.
Aminoglycosides v Tetracyclines v Chloramphenicol
All three are inhibit bacterial protein synthesis by disabling certain subunits. Aminoglycoside binds to 30s permanently disabling it. (bacteriocidal) Tetracycline binds to 30s and disrupts translation, Chloramphenicol binds to 50s and also disrupst translation
Fluroquinolones v Rifamycin v Fidaxomicin v Metronidazole
All 4 inhibit nucleic acid synthesis.
F= Prevent supercoiling of bacterial DNA
R= Prevents transcription
Fi=Binds to RNA polymerase and is bactericidal
M= Causes breaks in the DNA
Folate inhibitors are the most useful in this antibacterial method
Metabolic pathway disruption by disrupting nucleotide biosynthesis. An example of this drug is Sulfa drugs (i.e Trimethoprim)
Daptomycin v Polymyxins
Both attack the cell membrane. Daptomycin inserts into the microbes cytoplasmic membrane and Polymyxins bind to g- membranes
What is Mycobacterium tuberculosis, and why is it hard to treat?
Mtb is the bacteria that causes the contagious condition called tuberculosis. This bacteria is hard to treat because the cell wall has a waxy coating that makes it difficult for medication to penetrate.
MIC
MBC
SIR
Minimum Inhibitory Concentration= Lowest concentration that prevents growth in vitro
Minimum Bacterial Concentration= Lowest concentration that kills 99.9 of cells in vitro
Susceptible Intermediate Resistance
What kind of test is the Kirby-Bauer disc diffusion test?
KB is a test that is used to test microbe susceptibility to specific medications. Microbe in question is added to the plate that has an antibiotic on it. Then the colonies behavior is observed based on growth
What are the 6 ways a bacteria can evade the effects of Antibacterials?
Medication inactivating enzymes
Alteration in target molecule
Decreased medication uptake
Increased medication elimination
Spontaneous Replication
Gene Transfer
