Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
|
What are the major groups of antibiotics? (7)
|
beta-lactams
Aminoglycosides Glycopeptides Macrolides Tetracyclines Quinolones Antifolates |
|
|
What is the principle mechanism of action for antibiotics?
|
Competition for an active site of an enzyme
|
|
|
What is steric hindrance?
|
When inhibitor molecules prevent the components of the bacterial cell wall (disaccharides and pentapeptides) joining together - the enzyme intended for carrying out that function does not work.
|
|
|
How do bacteria become resistant to antibiotics? (5)
|
Destruction or inactivation of antibiotic
Prevention of antibiotic gaining entry to its site of action Alteration of the target Removeal of antibiotic from cell by antibiotic transport molecule Bypassing enzymes inhibited by antibiotic |
|
|
How can resistance develop in bacteria?
|
Mutation
Acquisition of DNA Up/down regulation of genes |
|
|
Why is there a risk of bacteria becoming more resistant?
|
Over the counter antibiotics
Mis-use of antibiotics by doctors Antibiotics in animal feeds |
|
|
What is the difference between an antimicrobial drug and and an antibiotic?
|
Antimicrobial drugs are synthetic, antibiotics are produced by living bacteria
|
|
|
How are ABX different from all other drugs?
|
They are used to attack, whilst all other drugs are used to repair.
|
|
|
How do beta-lactams attack bacteria?
|
Inhibit cell wall synthesis - leading to osmotic cell lysis
|
|
|
What are the main ways antibiotics attack bacteria? Why don't they affect the host?
|
Inhibiting cell wall synthesis, inhibiting protein synthesis. Don't affect host cells as they don't have cell walls or 70S (Svedberg) ribosomes.
|
|
|
What is the structure of the beta-lactam ring?
|
H..H
C--C |....| C--N || O |
|
|
What is the 'therapeutic index'?
|
A comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes drug toxicity
|
|
|
What are examples of antibiotics that inhibit cell wall synthesis?
|
Penicillin and vancomycin
|
|
|
What is an antibiotic that interferes with protein synthesis?
|
Quinolones
|
|
|
Where do beta-lactam antibiotics target the beta-lactam ring?
|
Between the C=O and N bond
|
|
|
How are bacterial cell walls synthesised?
|
By connecting blocks of disaccharides and pentapeptides.
|
|
|
In bacterial cell wall synthesis, what enzyme connects the disaccharides together, and what enzymes joins the pentapeptides together?
|
Transglycosylase joins sugars
Transpeptidase joins together pentapeptides. |
|
|
What antiviral is used to treat HIV? How does it work?
|
Zidovudine. Works by inhibiting reverse transcriptase
|
|
|
Another way ABX work is by affecting metabolic pathways - what goes on here?
|
Prevents folic acid being made - essential for bacteria but not for humans
|
|
|
How do antivirals work?
|
By acting as penetration inhibitors and nucleic acid inhibitors
|
|
|
Define efficacy
|
The ability to produce a desired or intended result
|
|
|
What are the influences of drug efficacy? (3)
|
Distribution (need good conc in INTENDED tissue - ABX intended for urinary tract that get broken down in the stomach won't work!)
Metabolism (can ABX be broken down in the body? Therefore ineffective?) Excretion (Can the ABX be safely removed by the patient's purification system?) |
|
|
What are aminoglycosides?
|
Antibiotics, however they can have severe ototoxicity (damage to the ear) and nephrotoxicity (damage to the kidneys)
|
|
|
What are the safety concerns with antibiotics? (4)
|
Interaction with other medications
Toxicity Hypersensitivity reactions Antibiotic resistance |
|
|
Define propensity
|
An inclination or natural tendency to behave in a particular way
'their innate propensity to attack one another' |
|
|
What effect can antibiotics have on contraception?
|
They can negate the effects - so must ask if someone is taking contraception before giving ABX
|
|
|
What is anaphylaxis?
|
A hypersensitivity reaction
|
|
|
What are the resistance mechanisms bacteria can evolve? (5)
|
New enzyme that degrades ABX
New pump that excretes ABX Loss of channel used for ABX entry New protein with lower affinity for ABX New enzyme/pathway allowing bypass of ABX |
