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34 Cards in this Set
- Front
- Back
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What are the 7 main examples of antibacterial drug classes? |
1. Quinolones 2. Rifamycins 3. Beta-lactams 4. Glycopeptides 5. Macrolides 6. Tetracyclines 7. Puromycin |
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How do quinolones work (basic target)? |
By inhibiting DNA replication and introducing breaks in DNA which causes lethal damage |
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What three essential cellular processes do they target? |
DNA synthesis, mRNA transcription and cell division |
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Give an example of a clinically relevant quinolone drug. |
Fluoroquinolones |
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WHat do fluoroquinolones target? |
That target DNA topisomerases such as DNA gyras and topoisomerase IV. |
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What do rifamycins target? |
They inhibit RNA synthesis |
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What kind of antibiotics are they? |
Semi-synthetic |
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How do rifamycins inhibit RNA synthesis? |
They bind to a subunit of the RNAP enzyme and this also inhibits DNA-dependent transcription. They also inhibit nascent RNA strand initialisation. |
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What are rifamycins used to treat? |
They are particularly good at targetting mycobacterium and are therefore used to treat TB, leprosy and mycobacterium avian complex infections. |
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How do beta-lactams work? (Basic target) |
By interfering in cell wall synthesis |
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Give three examples of beta-lactams. |
Penicillins, cephalosporins and carpabenems |
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How do beta-lactams interfere in cell wall synthesis? |
Bacterial cell walls are made up of a high percentage of peptidoglycan. Beta-lactams inhibit cross-lining of peptidoglycan layers by inhibiting the action of transpeptidases which catalyse the formation of peptide bonds. |
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What is the effect on the cell of beta-lactam treatment? |
Change in cell size and shape, induction of cellular stress responses and eventual cell lysis. |
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How do glycopeptide antibiotics work? |
They inhibit peptidoglycan synthesis by binding to individual peptidoglycan units and by blocking the action of transpeptidases and transglycosylases |
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What kind of bacteria might glyopeptide antibiotcs be effective against? |
Gram +'s only due to low permeability of the drug |
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Give an example of a glycopeptide antibiotic |
Vancomycin |
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What are three types of antibacterials that inhibit protein synthesis? |
Macrolides, tetracyclines and Puromycin |
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How do macrolides work? |
By binding to the 50S subunit of ribosomes |
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How do tetracyclines work? |
By binding to the 30S subunit of ribosomes |
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Why are ribosomes important? |
They are essential for the translation of mRNA |
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What is third way of inhibiting protein synthesis and give an example of an antibacterial that does this |
Puromycin works by inhibiting tRNA binding |
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What produces antibacterials? Give a specific example. |
Fungi and bacteria. Streptomyces produces around two thirds of clinically useful antibiotics. |
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Why is it important to give the correct dose of an antibiotic? |
High doses can have serious side effects. Low doses may not sufficiently clear the infection. |
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How is the correct dose of an antibiotic calculated? |
The minimum inhibitory concentration (MIC) and the minimum bacteriocidal concentration (MBC) is calculated. |
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Put the following in order of how bacteriocidal they are (beginning with the most): 1. Sterilisers 2. Detergents 3. Sanitisers 4. Disinfectants |
Steriliser, disinfectant, sanitiser, detergent |
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How do quaternary ammonium compounds work? |
They disrupt the cell membrane |
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How do chlorine-based compounds work? |
Disrupt cell membrane and damage DNA leading to cell lysis |
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Why might an antiseptic be used? |
To clean wounds and prevent infection |
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Give an example of an antiseptic and say how it works. |
Alcohol - denatures bacterial proteins |
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Give four examples of plants which have antimicrobial properties |
Cinnamon, ginger, lemon and cranberries |
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Give three examples of antimicrobial compounds that are present in certain plants. |
Terpenoids, alkaloids and saponins |
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How do terpenoids work? |
They damage the cell membrane of bacteria |
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How to alkaloids work? |
They damage the cell membrane and also disrupt gene regulatory systems such as QS and virulence factor production. |
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How do saponoins work? |
Act via their complex action with cholesterol to form pores in bacterial cell membranes which causes cell lysis. |
