antibiotics

Question 1

penicillans and cephalosporins

Answer 1

natural penicillan only works against gram +
all contain B lactam ring
irreversibly bind and inhibit transpeptidases in the periplasmic space
cell wall inhibitors

Question 2

chloramphenical

Answer 2

protein synthesis inhibitor
broad spec
can cause anemia

Question 3

streptomycin

Answer 3

protein synthesis inhibitor

gram - can cause deafness

Question 4

neomycin

Answer 4

protein synthesis inhibitor

topical streptomycin variant

Question 5

tetracyclin

Answer 5

protein synthesis inhibitor

broad spectrum, yeast over proliferation, also discolours developing teeth

Question 6

polymixens

Answer 6

damage gram - membranes

poorly absorbed and toxic to neurons and kidneys

Question 7

daptomycins

Answer 7

depolarizes gram + membranes

Question 8

polymyxin b and bacitracin

Answer 8

gram + cell wall inhibitor
valuable topical antibiotic
low usefulness as systemic drug

Question 9

rifamycin/rifampton

Answer 9

nucleic acid synthesis inhibitor
most useful against mycobacteria(tb, leprosy)
inhibits mrna synthesis
highly permeable into cell walls and through cell walls

Question 10

quinilones

Answer 10

nucleic acid synthesis inhibitor
inhibit dna gyrase -> dna replication
broad spectrum
ciprofloxin is the most well known

Question 11

sulfonamides

Answer 11

metabolic inhibitor

blocks an enzyme used to produce folate(produces thymine and uracil)

Question 12

sulfamethoxazole

Answer 12

competitively inhibits the synthesis of dihydrofolic acid from paba

Question 13

Modes of resistance

Answer 13

Drug modification/destruction
- B lactamases for penicillan
Pathway protection
- synthesis of false targets for tetracylin
target alteration
- single mutation in ribosome to prevent binding
Rapid efflux
- actively pumping out the antibiotic(heavy metal pumps)
Alternative pathways
- folate scavenging against sulfa drugs