DNA gyrase inhibitors and DNA strand breakers Flashcards Preview

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Flashcards in DNA gyrase inhibitors and DNA strand breakers Deck (28)
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1
Q

DNA gyrase is a topoisomerase. True or false?

A

True

2
Q

What is the role of DNA gyrase?

A

It is an enzyme that introduces negative (left-handed) superhelical turns into duplex bacterial DNA, using energy of ATP

3
Q

Why is supercoiling needed?

A

So DNA can fit into bacterial cell
Length of DNA helix 1300micrometers
Length of bacterial cell 1 micrometer

4
Q

DNA uncoils before replication and transcription. True or false?

A

True

5
Q

Why is DNA gyrase a good anti-bacterial target?

A

Mammals don’t supercoil DNA

6
Q

How do quinolones work?

A

Block the alpha subunit of DNA gyrase and prevent supercoiling of bacterial DNA. They interfere with DNA breakage and re-joining

7
Q

Quinolones are narrow-spectrum antibiotics. True or false?

A

False - broad spectrum

8
Q

Quinolones are effective against gram negative bacteria which are resistant to penicillins. True or false?

A

True

9
Q

Nalidixic acid is a quinolone that is active against gram negative bacteria only. True or false?

A

False - gram positive and negative

10
Q

Nalidixic acid is used for treatment of uncomplicated UTI. True or false?

A

True

11
Q

What are the indications for ciprofloxacin?

A

respiratory infections (not pneumococcal pneumonia)
UTI
gonorrhoea
prophylaxis of meningococcal minigitis
Anthrax - prophylaxis and post-exposure prophylaxis

12
Q

Ciprofloxacin is metabolised by CYP450 1A2. Why is this a problem?

A

Can lead to overdose of caffeine, warfarin and other drugs

13
Q

Absorption of which drug is reduced when magnesium or aluminium antacids are taken?

A

Ciprofloxacin

14
Q

Severe CNS disturbance can take place when ciprofloxacin is co-administered with which group of drugs?

A

NSAIDs

15
Q

Ciprofloxacin is contraindicated in pregnancy. True or false?

A

True

16
Q

Third generation quinolones are indicated in pneumonia and UTIs. True or false?

A

True

17
Q

Give the name of a third generation quinolone?

A

Levofloxacin

18
Q

What are the names of three second generation quinolones?

A

Ciprofloxacin
Norfloxacin
Ofloxacin

19
Q

What are nitrofurans used to treat and what is an example of one?

A

Gram positive and negative UTIs

Nitrofurantoin

20
Q

What are nitroimidazoles used to treat?

A

Anaerobic bacterial infections and protozoal infections

21
Q

The normal microflora of the intestine has roughly 500 species of bacteria. True or false?

A

True

22
Q

Elderly are especially susceptible to C.diff. True or false?

A

True

23
Q

Treating a patient who has C.diff with a broad spectrum antibiotic leads to elimination of most of the normal microflora of the intestine and promotes overgrowth of C.diff. True or false?

A

True

24
Q

How is C.diff treated?

A

Discontinue the inducing antibiotic, to allow reconstitution of the microflora
Rehydration
Oral metronidazole is first line treatment

25
Q

Oral metronidazole is first line treatment for C.diff. What is given as second line treatment?

A

Oral vancomycin

26
Q

How is C.diff transmitted?

A

Person-person
Hospital environment
Healthcare staff

27
Q

Spores are resistant to alcohol handwash. True or false?

A

True

28
Q

What is a new drug that has proven to be successful against C.diff?

A

Fidaxomicin