Antibiotics

Question 1

How do beta lactam drugs disrupt cell wall synthesis?

Answer 1

Bind to penicillin-binding proteins (PBP) inhibiting transpeptidases responsible for cross linking proteoglycans.

Question 2

Think penicillinoic acid think…

Answer 2

… degratation product - HYPERSENSITIVITY.

Question 3

Which type are outer (and inner) membrane surfactants?

Answer 3

Polymixins (polymixin B and E)

Question 4

Which polymixin in only used topically?

For example could be on an infected bee sting…

Answer 4

Polymixin B.

Question 5

Two side effects of polymixins:

Answer 5

neurotoxicity and nephrotoxicity

Question 6

How do quinolones stop DNA synthesis?

Answer 6

topoisomerase inhibitors.

Question 7

What do rifamycins inhibit that afford it selectivity?

Answer 7

Inhibit bacterial DNA dependent RNA polymerase (not human RNA polymerase)

Question 8

Two side effects of rifampin/rifampicin

Remember that liver transplant video.

Answer 8

Hepatotoxicity, discolouration of body fluids

Question 9

What drug would leprosy and tuberculosis need?

Answer 9

Rifampicin (rifamycins)

Question 10

What are rifamycins good for?

Answer 10

leprosy and tuberculosis.

Question 11

T of F - resistance develops quickly in rifamycins?

Answer 11

TRUE (RIfamycins - REsistance)

Question 12

Which drugs bind to the 30s subunit?

Answer 12

aminoglycosides,

tetracycline/doxycycline

Question 13

Which of the protein inhibiting drugs is the one that binds to the 50s subunit (not the 30S)?

Answer 13

Chloramphenicol

Question 14

What helps tetracycline selectivity along?

Not 100% selective

Answer 14

Accumulation via transport protein in the bacterial membrane.

Question 15

What can’t you eat with tetracycline?

Answer 15

Milk, aluminium, iron.

Question 16

What bacteria are aminoglycosides ineffective against?

Answer 16

+ve as well as strict anaerobes.

Question 17

_____ are good for most hospital acquired ANAEROBIC -VE bacteria.

Answer 17

Aminoglycosides

Question 18

Why aren’t amiNOglycosides effective against anaeobes?

Answer 18

Transport into the bacterium requires

Question 19

What’s PABA?

Answer 19

That’s the precursor to folate that bacteria need to convert. (p-aminobenzanoic acid)

Question 20

Which folate enzyme does tRimethopRim inhibit?

Answer 20

dihydrofolate Reductase

Question 21

Which folate enzyme do SulphanamideS inhibit?

Answer 21

dihydropteroate Synthase

Question 22

T or F: you’d expect sulphanamides to be given in combination with trimethoprim.

Answer 22

YES.

Question 23

Quinolones are ______ and all end in ______.

Answer 23

Topoisomerase (DNA) inhibitors; -flaxacin.

Question 24

What are two beta-lactamase inhibitors that you can combine with beta lactam drugs?

Answer 24

Clavulanic acid

Sulbactam

Question 25

What is clavulanic acid?

Answer 25

Beta-lactamase inhibitor

Question 26

What is sulbactam

Answer 26

Beta-actamase inhibitor

Question 27

Where would beta-lactamase inhibitors not be effective?

Answer 27

Another kind of resistance is make PBPs with low affinity for beta-lactam antibiotics.