Antimicrobrial chemotherapy- mechanisms of action Flashcards

1
Q

What are antibiotics active against?

A

bacteria

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2
Q

What is a bactericidal?

A

antimicrobial that kills bacteria

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3
Q

What is M.B.C?

A

minimal bactericidal concentration - minimum conc of antimicrobial needed to kill a given organism

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4
Q

What is bacteriostatic?

A

they do not kill bacteria but they inhibit the growth

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5
Q

What is MIC?

A

minimal inhibitory concentration- minimum concentration of antibiotic you need in order to inhibit the growth of the specific organism

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6
Q

What are the different routes of antibiotic administration?

A

topical: applied to surface
systemic: taken internally
parenterally: administered intravenously or intramuscularly

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7
Q

What are the classifications of sypherical, cocci bacteria?

A

diplococci, streptococci, staphylococci

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8
Q

What are the classifications of rod, bacilli bacteria?

A

chain of bacilli, flagellate rods, spore former

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9
Q

What are the classifications of spirals bacteria?

A

vibrios, spirilla, spirochettes

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10
Q

What are gram negative cocci?

A

neisseria
morasella

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11
Q

What are gram positive cocci?

A

staphylococcus
streptococcus
enterococcus
pneumococcus

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12
Q

What are gram negative bacilli?

A

escherichia coli
shigella
salmonella

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13
Q

What are gram positive bacilli?

A

corynebacterium
clostridium
listeria monocytogenes

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14
Q

What are the gram negative spirals?

A

vibrio cholerae
helicobacter pylori

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15
Q

How do the antibiotics work when they want to kill or inhibit the growth of specific bacteria?

A

Antibiotics may inhibit or kill bacteria by acting at three different areas of metabolic activity.

-inhibition of cell wall synthesis
-inhibit protein synthesis
-inhibition of nucleic acid synthesis

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16
Q

Why do antibiotics not interfere with human cells?

A

Human cells do not have any kind of cell wall

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17
Q

What antibiotics inhibit the cell wall synthesis?

A

Beta-lactams- Penicillins and Cephalosporins

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18
Q

Give characteristics of beta lactam antibiotics?

A

-bactericidal antibiotics
-effective mostly against Gram-positive bacteria

19
Q

Why are penicillin and cephalosporins classified as beta lactams?

A

chemical structure of drugs contain a beta lactam ring (square)

20
Q

Why are many gram negative organisms resistant to benzyl penicillin?

A

inability to penetrate gram negative cell wall

21
Q

Describe how glycopeptides (bactericidal antibiotics) are able to inhibit the cell wall synthesis?

A

-prevent two peptidoglycans to join
together to create a more stable cell wall
-vancomycin (glycopeptide) is going to prevent the two peptidoglycans to link to each other
-cell wall is disrupted

22
Q

Describe how penicillins and cephalosporins inhibit cell wall synthesis?

A

interfere with the specific kind of enzyme involved in the cross link between peptidoglycan bridges and cell wall. On the enzyme itself there is a specific binding site for the penicillin drug. Penicillin will interact with enzyme and inhibit it. Cell wall less strong

23
Q

How would you administer glycopeptides?

A

-can’t be given orally as cannot be absorbed by gastrointestinal tract, only given parentally

24
Q

What are the kind of antibiotics that are able to inhibit the protein synthesis of bacteria?

A

aminoglycosides

25
Q

Give characteristics of aminoglycosides?

A

inhibit the protein synthesis
concentration-dependent bactericidal antibiotics
useful in the treatment of serious Gram-negative infection

26
Q

How do aminoglycosides work?

A

antibiotic going to interfere with protein synthesis and prevent proper protein to be created.

27
Q
A

There are some differences between the ribosome structure in the bacteria and the mammalian ribosome. This makes antibody specific for bacteria, as antibody can discriminate between ribosomes. Targets 70S ribosome

28
Q

Give example of aminoglycoside?

A

gentamicin

29
Q

Give characteristics of macrolides?

A

useful alternatives to penicillins in treatment of Gram positive infections in patients who are penicillin allergic.

30
Q

Give name of a macrolide that can be used instead of penicillin?

A

erythromycin

31
Q

Give characteristics of tetracyclines?

A

bacteriostatic antibiotics
treatment of gram positive infections

32
Q

What bacteria is resistant to tetracycline?

A

percentage of bacteria like staphylococcus aureus, streptococcus pyogenes and streptococcus pneumonia that are actually resistant to the tetracycline.

33
Q

Give characteristics of oxazolidinones?

A

bacteriostatic or bactericidal
treatment of gram positive infections
last resort

34
Q

Give an example of an oxazolidinones?

A

linezolid

35
Q

Give characteristics of cyclic lipopeptides?

A

strong bactericidal antibiotics
treatment of gram positive

36
Q

Give example of a cyclic lipopeptide?

A

daptomycin

37
Q

How does the specific antibiotic, trimethoprim work?

A

inhibition of purine synthesis

bacteriostatic alone but when combined with antibiotics- bactericidal

inhibition of DNA synthesis either directly, or indirectly by interrupting the supply of precursors for DNA synthesis

38
Q

When is trimethoprim used?

A

treatment of urinary tract and chest infections

39
Q

Give another example of inhibitor of purine synthesis?

A

sulphamethoxazole

40
Q

What is co-trimoxazole a combination of?

A

trimethoprim and sulphamethoxazole

41
Q

Give characteristics of fluoroquinolones?

A

bactericidal antibiotics
particularly effective against gram negative
inhibiting enzyme involved in DNA synthesis
used orally as well as parenterally

42
Q

Give examples of fluroquinolones?

A

ciprofloxacin
levofloxacin- can be used against gram pos

43
Q
A