Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Antibiotics symposium 1: principles of antibiotics > Flashcards

Antibiotics symposium 1: principles of antibiotics Flashcards

1
Q

what is an antibiotic?

A

an agent produced by microorganisms that kill or inhibit the growth of other microorganisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the definition of a target site of an antibiotic?

A

points of biochemical reaction crucial to the survival of the bacterium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

which gram staining of bacteria has more peptidoglycan?

A

G+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the name of the protein that penicillin works on?

A

penicillin binding protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what drug classes come under beta lactams?

A

penicillins, cephalosporins and carbapenems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which class is also active against penicillin binding proteins but is not a beta lactams?

A

glycopeptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which antibiotics interfere with nucleic acid synthesis and function?

A

metronidazole

rifampicin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what type of bacteria can metronidazole kill?

A

anaerobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

which class of antibiotics works on inhibiting DNA gyrase?

A

fluoroquinilones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which antibiotic classes work on inhibition of ribosomal activity?

A 
aminoglycosides
tetracyclines
lincosamides 
macrolides 
chloramphenicol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which drug classes inhibit folate synthesis?

A

sulphonamides

trimethoprim

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does bacteriostatic mean?

A

inhibitory to growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

in what ways can antibiotics inhibit growth?

A

inhibit protein synthesis
inhibit DNA replication
interfere with metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

in what additional way do bacteriostatic antibiotics work?

A

they reduce production of toxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the main mechanism of bactericidal antibiotics?

A

inhibition of cell wall synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

when are bactericidal drugs particularly useful?

A

when there is poor tissue penetration by blood vessels
difficult to treat infections
need to eradicate infection quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the two major determinants of antibacterial effects?

A

concentration

time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which drugs have concentration dependent killing?

A

aminoglycosides

quinolones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

which drugs have time dependent killing?

A

beta lactams
clindamycin
macrolides
oxazolidinones

20
Q

which type of bacteria is flucloxacillin mainly for?

A

staphylococcus

21
Q

which antibiotic is used for MRSA?

A

vancomycin

22
Q

how does the half life/ elimination of the drug affect treatment?

A

affects the dosage intervals and duration of treatment

23
Q

what are the pt considerations before prescribing antibiotics?

A 
allergy or intolerance 
side effects
age 
liver and kidney function
pregnancy/breastfeeding 
drug interactions 
C. diff
24
Q

what are the 4 key ways that antibiotics confer resistance?

A

change the antibiotic target
destroy the antibiotic
prevent antibiotic access
remove antibiotic from bacteria

25
Q

describe how bacteria can change the antibiotic target

A

mutation in the gene for a protein to which the antibiotic binds causes the antibiotic to be unable to bind, or a gene mutates so that it produces a protein that binds to and blocks the antibiotic binding site

26
Q

give examples of antibiotics that are not sensitive due to change in antibiotic target

A

flucloxacillin no longer able to bind PBP of staph (MRSA)
wall components change in enterococci so reduce vancomycin binding
rifampicin activity reduced by RNA polymerase in myco. TB

27
Q

how do bacteria destroy an antibiotic

A

bacterial enzyme produced

28
Q

give examples of bacteria that can destroy antibiotics

A
  • beta lactamases hydrolyse beta lactam ring of penicillins and cephalosporins
  • staphylococci produce penicillinase so penicillin but not but not flucloxacillin is inactivated
  • G- bacteria phosphorylate aminoglycosides (gentamycin)
29
Q

How do bacteria prevent antibiotic access?

A

modify the porin channel size, numbers and selectivity

30
Q

give examples of bacteria that can prevent antibiotic access

A

pseudomonas aerguinosa against imipenem

G- bacteria against aminoglycosides

31
Q

how do bacteria remove antibiotic?

A

develop export or efflux proteins

32
Q

Give examples of bacteria that remove antibiotic

A

S. aureus or S. pneumoniae develop resistanance to fluoroquinolones
enterobacteriaceae get resistant to tetracyclins

33
Q

what are the methods of development of bacterial resistance?

A

intrinsic

acquired - conjugation, transduction, transformation

34
Q

give examples of intrinsic resistance (ie naturally resistant)

A

aerobic bacteria cant reduce metronidazole to its active form
vancomycin cannot penetrate the outer membrane of G- bacteria

35
Q

what is the definition of acquired resistance?

A

a bacterium that was previously susceptible obtains the ability to resist the activity of a particular antibiotic

36
Q

what is conjugation?

A

sex pilus forms through which a plasmid is transferred ‘bacterial sex’

37
Q

what is transduction?

A

bacteriophages that have donor bacterial DNA in them infect an bacterium and transfer the DNA to the recipient bacterium

38
Q

what is transformation?

A

bacteria can take up free DNA from the environment and incorporate it into their genome

39
Q

what are the important resistant G+ organisms?

A

MRSA

VRE - vancomycin resistant enterococci

40
Q

what does mecA do?

A

changes the binding site of penicillins as it encodes for a low affinity penicillin binding protein - resistance to all beta lactams

41
Q

which antibiotic class promotes VRE?

A

cephalosporins

42
Q

by what means do VRE gain their resistance?

A

aqcuisition of a plasmid - gene prevents vancomycin binding

43
Q

how are gram - bacteria resistant to antibiotics?

A

they can produce beta-lactamases eg E. col, H. influenzae, N. gonorrhoea, Klebsiella pneumoniae
ESBL - more extended beta lactam inhibition
ampC beta-lactamase resistance - broad spectrum penicillin, cephalosporin, monobactam resistance, beta lactamase inhibitor resistant with inducible expression

44
Q

what type of antibiotics were developed to combat G- resistance?

A

carbapenems

45
Q

give examples of carbapenems

A

ertapenem, imipenem, meropenem, doripenem

46
Q

what is the advantage of carbapenems over other beta lactams?

A

highly resistant to degradation by beta lactamases or cephalosporinases

47
Q

is there resistance to carbapenems?

A

Yes - carbapenemases

Pharmacology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions