Brainscape's Knowledge GenomeTM

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


See full index

MICRO ADYA > Microbiology 2 - Antimicrobial agents 1 > Flashcards

Microbiology 2 - Antimicrobial agents 1 Flashcards

1
Q

What is the broad mechanism of action of beta lactams?

A

Inhibition of cell wall synthesis

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

What is the broad mechanism of action of glycopeptide antibiotics?

A

Inhibition of cell wall synthesis

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

What 3 groups of antibiotics are classified as beta lactams?

A

Penicillins
Cephalosporins
Carbapenems

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

Name 2 glycopeptide antibiotics

A

Vancomycin
Teicoplanin

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

Describe the mechanism of action of beta lactams

A

Inhibits transpeptidase, which is an enzyme that forms cross links during the formation of the cell wall.
The resulting cell wall is therefore weak, and so the bacteria lyse because of osmotic pressure.

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

How does the cell wall of gram pos and gram neg bacteria differ?

A

Gram pos has peptidoglycan

so stains purple

gram negative - thinner peptidoglycan layer- stains pink

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

What bacteria is penicillin active against?

A

Gram pos

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

What bacteria is amoxicillin active against?

A

Broad spectrum: gram pos and many gram neg

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

Is streptococci gram pos or neg?

A

Gram pos

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

Which beta lactam antibiotic is effective against pseudomonas?

A

Piperacillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How can beta lactam resistance be overcome?

A

Include a beta lactamase inhibitor
Eg. Clavulanic acid + amoxicllin (in co-amoxiclav)
e.g. Piperacillin + tazobactam

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

Is pseudomonas gram pos or gram neg?

A

Gram neg

(Pseudo”moan”as - ‘moan’ = negative)

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

Is neisseria meningitis gram pos or gram neg?

A

Gram neg

(Neisseria starts with N = negative)

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

Recall an antibiotic that is associated with C. difficile

A

Ceftriaxone (cephalosporin)

clindomycin

coamoxiclav

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

Which beta lactam antibiotics are stable to ESBL organisms?

A

Carbapenems

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

Recall a caution of beta lactam antibiotic

A

Excreted renally so reduce dose if renal impairment

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

What type of bacteria are glycopeptides effective against?

A

Gram pos only - they are large molecules so can’t penetrate gram neg cell wall

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

What are glycopeptides particularly useful for?

A

MRSA infection

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

What is a caution of glycopeptide antibiotics?

A

They are nephrotoxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Recall the broad mechanism of action of glycopeptide antibiotics

A

Prevent peptide cross links in cell wall
By prevent transpeptidase binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Recall the broad mechanism of action of aminoglycosides

A

Bind to 30s ribosomal subunit, preventing elongation of polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Recall 2 examples of aminoglycoside antibiotics

A

gentamicin
amikacin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What type of bacteria are aminoglycoside antibiotics effective against?

A

Gram neg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Recall 2 toxicities of aminoglycosides

A

Ototoxicity
Nephrotoxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What type of bacteria are macrolides effective against?

A

Gram pos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are macrolides particularly useful for?

A

Mild staph or strep infections in patients who are allergic to penicillin

Also active against Campylobacter sp and Legionella pneumophillia.

  • Given for atypical pneumonia due to other organisms such as mycoplasma >>> b-lactam coupled with a macrolide which will treat atypical agents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Recall 2 macrolide antibiotics

A

Azithromycin
Clarithromycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What type of bacteria are tetracylines effective against?

A

They are broad spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Recall a class of antibiotic you should never give to children or pregnant women

A

Tetracyclines:

  • Can be deposited in growing bone and discolour growing teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Recall one side effect of tetracycline antibiotics

A

Light-sensitive rash- esp doxycylcine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Recall the broad mechanism of action of macrolides

A

Bind to the 50s subunit of ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Recall the broad mechanism of action of tetracyclines

A

Bind to 30s subunit of ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What type of bacteria is chloramphenicol effective against?

A

Many - it is v broad spectrum

34
Q

Why is chloramphenicol rarely used?

A

Risk of aplastic anaemia and grey baby syndrome in neonates due to inability to metabolise drug

35
Q

Recall 2 specific bacteria that macrolides are effective against

A

Campylobacter sp
Legionella pneumophila
(macrolides = erythromycin/ azithromycin/ clarithromycin)

azithroymcin does have some gram negative cover

36
Q

Recall the broad mechanism of action of chloramphenicol

A

Binds to 50s subunit of ribosomes - inhibits formation of peptide bonds during translation

37
Q

Recall the broad mechanism of action of oxazolidinones

A

Binds to the 23s and 50s subunit of ribosomes to prevent 70s subunit formation

38
Q

Recall two types of bacteria that oxazolidinones are particularly active against

A

MRSA and VRE-vancomycin or glycopeptide resistant enterococci

Highly active against Gram +ve organisms

39
Q

Recall an example of oxazolidinones

A

Linezolid

40
Q

Recall 2 potential side effects of oxazolidinones

A

Thrombocytopaenia- common and reversible

  • Can cause optic neuritis, particularly with use > 4 weeks- irreversible
41
Q

Recall the broad mechanism of action of fluoroquinolones

A

Act on alpha subunit of DNA gyrase

42
Q

Recall 4 uses of fluoroquinolones

A

UTI
Pneumonia
Atypical pneumonia
Bacterial gastroenteritis
Ear infection

43
Q

Recall 2 examples of fluoroquinolone antibiotics

A

Levofloxacin- - in the middle
Moxifloxacin- good for Gram +ves (inc. pneumococcus) but worse for Gram-ves

Ciprofloxacin- good for Gram -ves including P. aeruginosa

44
Q

Give an example of a nitromidazole antibiotic

A

Metronidazole

Nitrofurantoin is a related compound

45
Q

Recall types of organisms that metronidazole is effective against

A

Anaerobes
Protozoa- Giardia

46
Q

When should nitrofurantoin be taken?

A

Right after visiting the toilet as it sits in bladder

47
Q

Recall the broad mechanism of action of rifampicin

A

Binds to DNA-dependent RNA polymerase to inhibit RNA synthesis

48
Q

Recall the main use of rifampicin

A

TB treatment

49
Q

Recall one side effect of rifampicin

A

Turns secretions orange

50
Q

Recall one condition of rifampicin prescription

A

Should never be prescribed alone as resistance develops very quickly

51
Q

Colistin is very toxic. Why is it coming back into use?

A

It is active agianst certain multi-drug resistant bacteria

NB: colistin = polymyxin

Active against Gram -ve organisms, including P. aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae

52
Q

What is daptomycin licensed for the treatment of?

A

MRSA
VRE

53
Q

Recall the 2 classes of antibiotic that inhibit folate synthesis

A

Sulphonamides
Diaminopyrimidines

54
Q

Give an example of a sulphonamide

A

Trimethoprim

(and also sulfamethoxazole)

55
Q

What is the main use of trimethoprim

A

Uncomplicated UTI

56
Q

What are the 4 main mechanisms of resistance

A
  1. Inactivation (eg beta latamases)
  2. Altered target (so antibiotic no longer binds - important in MRSA where bacteria change the penicillin-binding protein, and in protein-synthesis inhibitors where the binding of the ribosome subunit is prevented)
  3. Reduced accumulation
    (most important in gram negs - either due to efflux or to reduced uptake)
  4. Bypass
    (particularly important for folate inhibitors - bacteria can change the enzyme they use)

BITE
Bypass
Inactivation
Target- altered target
Efflux

57
Q

Which antibiotic is best for treating PCP?

A

Co-trimoxazole

trimethoprim + sulfomethoxazole

58
Q

What is the broad mechanism of action of nirtromidazoles?

A

Inhibit DNA synthesis

59
Q

Which bacteria typically forms “gram pos cocci in clusters”?

A

Staphylococcus

Staph- shepherds hold staff to gather sheep in clusters

60
Q

Which bacteria typically forms “gram pos cocci in chains”?

A

Streptococcus
Strep sounds like ‘stripe’ = chain

61
Q

What gram stain status are enterococci?

A

Positive

(“Enter-o-coccus” = like letting someone in, positive thing to do)

62
Q

Is haemophilus gram pos or neg?

A

Gram neg
Ha”emo”philus - emo = negative

63
Q

Is listeria gram pos or neg?

A

Positive
Lister = good man = positive

64
Q

which antibiotics active in SYNERGISTIC combination with b-lactams

A

aminoglycosides

  • Used in combination in some infections i.e. endocarditis
65
Q

which aminoglycosides are particualrly active against pseudomonas

A

Gentamicin and tobramycin

66
Q

are aminglycosides good for abscesses

A
  • Aminoglycosides are inhibited by low pH and so are not very effective in abscesses
67
Q

what do tetracyclines have acitivity against

A

broad spectrum:

activity against Intracellular pathogens (legionella)

pathogens with no cell wall (e.g. chlamydiae, rickettsiae and mycoplasma)

most conventional bacteria

  • Good for atypical pneumoniae- mycoplasma
  • Good for skin + soft tissue infections
  • MRSA tend to be sensitive to tetracyclines
68
Q

examples of tetracylcine

A

doxycycline

Tigecycline

69
Q

which class of drug is azithroymycin and what is special about it

A

Some activity against gram -ve (azithromycin) unlike most other macrolides

  • May be used for Salmonella typhi and often in bronchiectasis or in CF patients
70
Q
  • Side effects of quinolones
A
  • C. difficile outbreaks associated with quinolone
  • Tendonitis can occur especially Achilles tendonitis – use in caution in elderly and those on steroids
  • Reduced seizure threshold- can’t be used in those with seizures/epilepsy
71
Q

Cell Membrane Toxins

which two antibiotics affect bacteria when they are not dividing/no metabolically active

A
  • Daptomycin
  • Colistin

Cell Membrane Toxins

72
Q

which bacteria do daptomycins work against

A

activity limited to Gram +ve,

  • Good activity mainly against S. aureus
73
Q

what is co-trimoxazole and wha does it treat

A

combination of sulphamethoxazole + trimethroprim

treating Pneumocystis jiroveci pneumonia, hospital acquired pneumoniae, skin/soft tissue infections

74
Q
  • Extended spectrum beta lactamases are able to break down what
A

PENCILLINS AND CEPHALOSPORINS

75
Q
A
  • Flucloxacillin resistance is MRSA resistance- Alteration of the target site: altered penicillin binding protein
  • This is because flucloxacillin is stable to beta lactams but if they do become resistant then this indicates MRSA.
76
Q

By which mechanism is ESBL E. coli resistant to Ceftriaxone?

A
  • Enzymatic inactivation of the antibiotic (as it is extended spectrum b__-lactamase)
77
Q
A
78
Q

examples of antibiotics and their type of resitance mechanisms

A
79
Q

Which of the following ECG abnormalities does moxifloxacin cause:

Prolonged QTc

Flattened lateral T waves

Prolonged PR interval

Ventricular ectopics

Sinus tachycardia

A

Prolonged QTc

80
Q

Aminoglycosides have good action against:

Aerobes

Anaerobes

A

Aerobes

Gram-negative – E. coli, proteus, Enterobacter, psudomonas
Gram-positive (in conjunction with beta-lactam) – staph aureus and coagulase negative staph, viridans streptococci, enterococcus

81
Q

Which of the following is not a recognised adverse effects of aminoglycoside antibioitcs (e.g. amikacin, gentamicin):

Nephrotoxicity

Ototoxicity

Neuromuscular paralysis

Nausea and vomiting

Hyponatraemia

A

Hyponatraemia

MICRO ADYA (22 decks)

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