DNA gyrase inhibitors and DNA strand breakers

Question 1

DNA gyrase is a topoisomerase. True or false?

Answer 1

True

Question 2

What is the role of DNA gyrase?

Answer 2

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

Question 3

Why is supercoiling needed?

Answer 3

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

Question 4

DNA uncoils before replication and transcription. True or false?

Answer 4

True

Question 5

Why is DNA gyrase a good anti-bacterial target?

Answer 5

Mammals don’t supercoil DNA

Question 6

How do quinolones work?

Answer 6

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

Question 7

Quinolones are narrow-spectrum antibiotics. True or false?

Answer 7

False - broad spectrum

Question 8

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

Answer 8

True

Question 9

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

Answer 9

False - gram positive and negative

Question 10

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

Answer 10

True

Question 11

What are the indications for ciprofloxacin?

Answer 11

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

Question 12

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

Answer 12

Can lead to overdose of caffeine, warfarin and other drugs

Question 13

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

Answer 13

Ciprofloxacin

Question 14

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

Answer 14

NSAIDs

Question 15

Ciprofloxacin is contraindicated in pregnancy. True or false?

Answer 15

True

Question 16

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

Answer 16

True

Question 17

Give the name of a third generation quinolone?

Answer 17

Levofloxacin

Question 18

What are the names of three second generation quinolones?

Answer 18

Ciprofloxacin
Norfloxacin
Ofloxacin

Question 19

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

Answer 19

Gram positive and negative UTIs

Nitrofurantoin

Question 20

What are nitroimidazoles used to treat?

Answer 20

Anaerobic bacterial infections and protozoal infections

Question 21

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

Answer 21

True

Question 22

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

Answer 22

True

Question 23

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?

Answer 23

True

Question 24

How is C.diff treated?

Answer 24

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

Question 25

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

Answer 25

Oral vancomycin

Question 26

How is C.diff transmitted?

Answer 26

Person-person Hospital environment Healthcare staff

Question 27

Spores are resistant to alcohol handwash. True or false?

Answer 27

True

Question 28

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

Answer 28

Fidaxomicin