Antimicrobials - B-lactams

Question 1

Cell wall synthesis can be targeted in bacteria using B-lactams. However, vancomycin cannot be used. True or false?

Answer 1

False - B-lactams and vancomycin can be used

Question 2

It is more difficult to prevent bonds being formed than break them in a bacterial cell wall. True or false?

Answer 2

False - more difficult to break bonds than prevent them from being formed

Question 3

Gram stain on gram positive bacteria cannot be washed out by acetone. True or false?

Answer 3

True

Question 4

Gram stain on gram negative cannot be washed out by acetone. True or false?

Answer 4

False - can be

Question 5

Are norcardiform bacteria gram positive or negative?

Answer 5

Positive

Question 6

Give two examples of norcardiform bacteria.

Answer 6

M.tuberculosis and mycobacteria

Question 7

The cross-link of polysaccharide chains on peptidoglycans is species dependent. True or false?

Answer 7

True

Question 8

What sort of reaction forms crosslinks on peptidoglycans?

Answer 8

Transpeptidation

Question 9

Give three examples of B-lactam antibiotics

Answer 9

Penicillins
Cephalosporins
Carbapenems

Question 10

Who discovered penicillins?

Answer 10

Fleming

Question 11

What was the main barrier Fleming faced when producing penicillin?

Answer 11

Cultivating the fungus

Question 12

What was the antibacterial broth prepared from in Flemings discovery of penicillin?

Answer 12

penicillium notatum fungus

Question 13

What are the three amino acids that make up penicillin G?

Answer 13

Cysteine
Valine
Phenylalanine

Question 14

How do B-lactams work?

Answer 14

form covalent interactions with transpeptidase/carboxypeptidase

Question 15

6-aminopenicillinic acid is a ____________ penicillin

Answer 15

semi-synthetic

Question 16

6-aminopenicillinic acid has independent antibacterial activity. True or false?

Answer 16

False - can be built up in lab to produce amoxicillin

Question 17

Penicillin G is resistant to B-lactamases. True or false?

Answer 17

False- sensitive to them

Question 18

Which penicillin can be taste-masked?

Answer 18

Amoxicillin

Question 19

Which class of B-lactamase enzymes is amoxicillin resistant to?

Answer 19

Class 1

Question 20

Which two penicillins are resistant to all B-lactamases?

Answer 20

Flucloxicillin

Methicillin

Question 21

1st generation cephalosporins are widely used today. True or false?

Answer 21

False - rarely used

Question 22

2nd generation cephalosporins are administered orally. Are they gram positive or negative?

Answer 22

Negative

Question 23

Are 3rd generation cephalosporins gram negative or positive?

Answer 23

negative

Question 24

Cefaclor is a 2nd generation cephalosporin. Which bacteria is it mainly used against?

Answer 24

Haemophilus

Question 25

Which generation of cephalosporins is ceftriaxone?

Answer 25

3rd generation

Question 26

Carbapenems have narrow-spectrum activity. True or false?

Answer 26

False - broad-spectrum

Question 27

Carbapenems are resistant to most B-lactamases. True or false?

Answer 27

True

Question 28

Imipenem is rapidly deactivated by the kidneys unless administered with _______

Answer 28

cilastatin

Question 29

Astreonam is the only monobactam. True or false?

Answer 29

True

Question 30

Vancomycin is a ribosomal peptide. True or false?

Answer 30

False - non-ribosomal

Question 31

Vancomycin is used to treat gram-negative infections only. True or false?

Answer 31

False - gram positive infections only

Question 32

Vancomycin is usually injected. Why?

Answer 32

Because the digestive system hydrolyses peptides

Question 33

Vancomycin can be used to treat MRSA. However, there is a preferred treatment. What is it?

Answer 33

rifampicin-vancomycin combination

Question 34

What is oral vancomycin used for?

Answer 34

clostridium difficile (infections of the gut)

Question 35

What is an alternative drug to vancomycin that has a very similar mode of action?

Answer 35

Teicoplanin

Question 36

Vancomycin side effects may have been exaggerated early on. Why?

Answer 36

Due to impure preparations