Antibiotics - Quinolones

Question 1

In order for a cell to replicate, it must go through mitosis. In order to do this the DNA must be condensed and then uncoiled so that it can be separated and then replicated. A specific enzyme is responsible for unwinding the DNA. What is the enzyme called?

1 - helicase
2 - ligase
3 - primase
4 - DNA gyrase

Answer 1

4 - DNA gyrase

• if DNA cannot be unwound then it cannot replicate and cells will die

Question 2

Which of the following is the core Quinolone that we need to be aware of?

1 - Doxycycline
2 - Clarithromycin
3 - Erythromycin
4 - Ciprofloxacin

Answer 2

4 - Ciprofloxacin

Question 3

Ciprofloxacin is the core Quinolone that we need to be aware of. What is the mechanism of action of these antibiotics?

1 - inhibit DNA gyrase
2 - interfere with NAG and NAMs
3 - bind to 50S ribosome
4 - binds to A site on the 30S ribosome

Answer 3

1 - inhibit DNA gyrase
- topoisomerase II and IV
- DNA cannot unwind and cell will eventually die

Question 4

Ciprofloxacin is the core Quinolone that we need to be aware of. Is this a bactericidal or bacteriostatic?

Answer 4

• bactericidal
• cells cannot replicate and die

Question 5

Ciprofloxacin is the core Quinolone that we need to be aware of. Is this a broad or narrow spectrum antibiotic?

Answer 5

• broad spectrum
• specifically effective against Gram - bacteria
• against a variety of pathogens including aerobic gram-negative (Chlamydia trachomatis, Legionella bacterium, Mycoplasma), and anaerobes.
• effective against some gram-positive organisms

Question 6

Ciprofloxacin is the core Quinolone that we need to be aware of. It is broad spectrum, but effective against Gram - bacteria. Specifically one bacteria called what?

1 - Klebsiella
2 - Acinetobacter
3 - Pseudomonas aeruginosa
4 - E. coli.

Answer 6

3 - Pseudomonas aeruginosa

Question 7

Ciprofloxacin is the core Quinolone and it is usually reserved for severe infection where other treatments are not available. They can be used in severe UTIs. Is this against Gram negative or positive bacteria?

Answer 7

• Gram negative
• mostly

Question 8

Ciprofloxacin is the core Quinolone and it is usually reserved for severe infection where other treatments are not available. They can be used in severe gastroenteritis. Which 2 bacteria does this kill that cause gastroenteritis?

1 - Helicobacter pylori
2 - Shigella
3 - E. coli
4 - Campylobacter

Answer 8

2 - Shigella
4 - Campylobacter

Question 9

Ciprofloxacin is the core Quinolone and it is usually reserved for severe infection where other treatments are not available. They can be used in lower RTI, such as COPD exacerbations and pneumonia. Does this work against Gram negative, positive or both?

Answer 9

• able to function against both

Question 10

Ciprofloxacin is the core Quinolone can cause GI upset. Why does this antibiotic cause GI upset?

1 - irritates mucosal membrane
2 - has osmotic effect inducing diarrhoea
3 - healthy flora are killed causing C. difficile and colitis
4 - stimulates serotonin receptors and induces nausea and vomiting

Answer 10

3 - healthy flora are killed causing C. difficile colitis

• Nausea, vomiting and diarrhoea also present

Question 11

Ciprofloxacin is the core Quinolone and can cause all of the following adverse events, EXCEPT which one?

1 - ototoxicity
2 - delayed hypersensitivity reactions
3 - neurological dysfunction (convulsions, peripheral neuropathy)
4 - musculoskeletal damage (tendons rupture)
5 - cardiovascular dysfunction (QT interval prolongation and valvular)

Answer 11

1 - ototoxicity
- no evidence of this

Question 12

Ciprofloxacin is the core Quinolone and should be prescribed with caution in all of the following EXCEPT which one?

1 - children and young adults
2 - hepatic impairment
3 - pregnant women
4 - adults >60 y/o
5 - renal impairment
6 - neurological dysfunction/disease
7 - cardiovascular disease

Answer 12

2 - hepatic impairment

• excreted by kidneys

Question 13

Ciprofloxacin is the core Quinolone absorption and efficacy is affected by which of the following in the GIT?

1 - iron
2 - Ca2+
3 - antacids
4 - all of the above

Answer 13

4 - all of the above
- essentially any divalent cations
- minimum of 2 hour gap before or after food

Question 14

Ciprofloxacin is the core Quinolone. This drug can inhibit cytochrome P450 enzyme variations, meaning what can happen to other drugs?

Answer 14

• reduces the metabolism of other drugs, meaning they can become toxic and increase risk of adverse events

Question 15

In severe infections how is Ciprofloxacin typically administered?

1 - oral
2 - IV
3 - IM
4 - suppository

Answer 15

1 - oral
- absorbed well from GIT with long half life so administered every 12-24h

• reserved for IV if patient is unable to take orally

Question 16

When prescribing any antibiotics, in accordance with antibiotic stewardship, which of the following must be document on the prescription and in the patients notes?

1 - indication
2 - review date
3 - treatment duration
4 - all of the above

Answer 16

4 - all of the above

Question 17

If prescribed as IV, how long should it be before the antibiotics are switched to oral where appropriate?

1 - 12h
2 - 24h
3 - 48h
4 - 72h

Answer 17

3 - 48h

Question 18

Broad spectrum antibiotics are prescribed empirically, when we do not know the specific cause of the infection. However, what is the main driver to switch antibiotics to a narrow spectrum antibiotic?

1 - cost
2 - patients request
3 - microbiology results
4 - allergies

Answer 18

3 - microbiology results