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32 Cards in this Set
- Front
- Back
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Bacteriostatic Antibiotic vs. Bacteriocidal Antibiotic
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Bacteriostatic: inhibit bacterial growth. (they dont kill bacteria) Relies on innate and acquired immune system to reomove pathogenic bacteria
Bacteriocidal: kills bacteria! |
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For immunocompromised patients, is bacterio static or cidal more effective?
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Cidal!. Static antibiotics usually are not effective for the immunocompromized.
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MIC stands for what
MBC stands for what |
Minimum inhibitory concentration for bacteriostatic agents to inhibit bacterial growth
Minimum bactericidal concentration of antibiotic that kills bacteria |
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Antibiotics:
Anti-metabolites and most inhibitors of protein syntehsis are usually bacteriostatic or cidal? INhibitors of cell wall synthesis and agents affecting cell membrane permeability are bactericidal or static? |
Static!
Cidal! |
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Broad spectrum antibiotics vs Narrow Spectrum Antibiotics. What is their target?
What is the basis for such specificity between antibiotics? |
Broad: kills both gram + and gram -
Narrow : One or the other, not both Antibiotics often cannot penetrate through the cell envelope- outermembrane of Gram- bacteria and cell wall of gram + |
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What are some methods to kill bacteria?
What is the most common mechanism of antibiotic activity? This type of antibiotic is classifed as :? |
1. You can damage inhibit cell wall synthesis
2. inhibit DNA replication by inhibiting DNA gyrase 3. Go after RNA and inhibit RNA polymerase 4. Inhibit protein synthesis Most Common: inhibiting bacterial ell wall synthesis Beta Lactam Antibiotics |
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Structurally, how are beta Lactam antibiotics similar?
What is an example of beta lactam antibiotic Bacteriocidal or Bacteriostatic? |
They all share a beta lactam ring structure which functions to inhibit bacterial cell wall synthesis
Penicillin Cidal! |
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IF a bacteria is resistant to penicillin, how does it do it?
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It cleaves the four member ring of penicilin!
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Penicillin G vs Penicillin V. Differences in terms of When to use each and how is it taken?
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G: to treat infections caused by a limite dnumber of susceptible organisms. Its incompleley absorbed because it is INACTIVATED BY GASTRIC ACID.
Given Intravenously! V: more resitant to acid and preffered oral form to treat suscebtible bacteria! |
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IN general , how do bacteria develop resistance to antibiotics?
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Get the antibiotic binding proteins in the bacteria to mutate
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Resistance to penicillin often occurs through what molecule?
What is one way to evade this bacterial resistance? |
Plasmid Encoded beta lactamases. They hydrolyze the beta lactam ring of penicillins
Adding beta lactamase inhibitors to penicillins! |
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Antibiotic: Cephalosporins/Cephamycins simialr to penicillin how?
Different how? |
They have beta lactam ring! They have the same mechanism of cell wall inhibition!
Difference: wider antibacterial spectrum, resistance to beta lactamases, improved pharmacokinetic properties! |
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Which should be implemented first, narrow or broad spectrum antibiotic?
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Narrow --> then broad. IF broad is given first, resistance will develop.
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Vancymycin(antibiotic) is used to manage infections caused by :
What is a problem current in clinical medicine: |
oxacillin resistant staphyloccocci and other gram + resistant to beta lactam antibiotics
Resistance of enterococcus to vancomycin! |
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Vancomycin is a glycopeptide that fcns by:
Functions specifically by: |
disrupting cell wall peptidoglycan synthesis in growing gram + bacteria
Inferering with amino acid termini of bridges connectiving peptidoglycan chains. |
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Bacitracin is a polypeptide used to treat what symptom cause by gram + bacteria?
It Fcns how? |
Skin infections!
inhbiits cell wall synthesis |
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Polymyxins are most effective against gram + or - bacteria?
They can cause serious nephrotoxicity. Their use is limited to what:? |
gram -
extrenal treatment of localized infections eg: eye infections, skin infections |
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Izoniazid, Ethionamide, Ethambutol and Cycloserine fight bacteria how? Primary mode of attack:
Izoniazid is used to treat: |
Cell wall antibiotics!
TB |
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What is the second largest class of antibiotics? (first class is cell wall antibiotics)
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Act by inhibiting protein synthesis!
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Members of the protein synthesis antibiotics include:
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aminoglycosides, tetracyclines, oxazolidnones, cholramphenicol, macrolides, clindamycin, streptogramins
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Aminoglycosides act how:
Bacteriocidal or static? why? Used to treat gram positive or negative? eg: ? mechanism of protein synthesis inhibition? Many bacteria are resistance. How can you solve this problem: |
inhibit protein synthesis
Bacteriocidal! Why? they irreverisibly bind to ribosomes! Many gram negative, some gram + eg strepotomycin they irreversibly bind to 30S ribosomal proteins Co-administration with an inhibitor of cell wall synthesis |
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Resistance to antibacterial action of aminoglycosides can develop by:..
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1 Mutation of ribosomal binding site
2 Decreased uptake of antibiotic into bacterial cells 3. Icnreased expulsion of antibiotic from cells 4 Enzymatic modification of the antibiotic |
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What is special about enterococcus? Is it a gram - or + bacteria?
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It can only be killed by the synergistic combination of aminoglycoside plus an antibiotic that inhibits cell wall synthesis!
Gram Negative Coccus! |
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Tatracyclines are similar to aminoglycosides how?
Used to treat gram + or -? or both? Different how? |
Inhibit protein synthesis by binding 30S ribosomal subunit, but they do it reversible!
treat both gram + and -. |
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Resistance to tetracylines arise how?
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1. Decreased penetration of antibiotic into bacterial cells
2 Mutation in the chromosomal gene encoding outer membrane porin protein |
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Oxaxolidnones (another protein synthesis antibiotic)
Narrow or broad spectrum? Mechanism of protein synthesis inhibition? |
Narrow spectrum!
binds to 50S robosomal subunit |
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Chloramphenicol: (another protein synthesis antibiotic)
broad or narrow spectrum? What is dangerous about it and why isnt is used in the US? |
broad
it disrupts protein synthesis in human bone marrow cells and can produce aplastic anemia! |
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Macrolides (another protein synthesis antibiotic)
Broad or narrow spectrum? bacteriostatic or cidal? used to treat what type of infection:? |
broad spectrum
bacteriostatic Pulmonary infection |
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CLindamycin: (another protein synthesis antibiotic)
Active against gram - or +? Mechanism: |
gram negative!
B binds to 50S ribosome; inhibiting elongation of proteins |
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Third class of antibiotics are: (other than cell wall synthesis and protein synthesis antibiotics)
Name of Bacterias in this category(3): GRam - or +? both? |
Inhibition of bacteria DNA or RNA synthesis
1 Quinolones!: inhibit unwinding of the DNA from the helical structure! 2. Rifampin 3. Metronidazole Both! |
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Rifampin functions by:
Rifampin resistance in gram positive bacteria results from:? How do GRam - bacteria react with Rifampin? |
binds to dna dependent RNA polymerase, inhitis initiation of RNA synthesis
mutation in chromosomal gene that encodes beta subunit of RNA polymerase Gram - bacteria are intrinsically resistant to rifampin because of decreased uptake |
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THe fourth class of antibiotics (exclusind cel wall, protein synthesis, DNA/RNA, ) is:
Name of category: Mechanism of action: gram - or gram +? both? Used to treat: |
Antimetabolites
Sulfonamide prevent synthesis of folic acid required by certain micro organisms Both! Broad! Acute urinary tract infections (e. coli) |
