Bailey: Effects of Ab

Question 1

_____ described that potential usefulness of penicillin in ____

Answer 1

Fleming 1920

Question 2

_____ and ____ demonstrated the safety and effectiveness of penicillins in humans (changed the scope of WWII) in _____

Answer 2

Chain and Flory 1940

Question 3

Antibiotics modes of action?

Answer 3

bacterostatic= reduces ability to replication
bactericidal= kills bac

Question 4

Ideal Antibiotic:
\_\_\_\_\_\_ spectrum of activity
would not induce resistance
\_\_\_\_ therapeutic index
\_\_\_\_ toxicity

Answer 4

appropriate
high-want large ratio
selective-kills bac but leaves host unaffected

Question 5

Achieving Selective Toxicity by:

• _________ are unique in microbes
• ______ for replication, transcription and translation can be unique in microbes
• microbes have some unique essential _______
• ____ structure unique in microbes

Answer 5

cell wall and membrane
enzymes
metabolites
ribosomes

Question 6

Antibody Inhibition of Bac:

• prevention of NAG and NAM binding
• prevention of amino acids from binding to NAM
• preventing chain from elongation
• preventing formation of peptide bonds

Answer 6

inhibition of cell wall synthesis

Question 7

How does penicillin disrupt cell wall synthesis?

Answer 7

by preventing the formation of peptide bonds

• pen. structure similar to bond
• ez cleaves pen instead of D-ala
• cleaves into more toxic form which kills bac

Question 8

Antibody Inhibition of Bac:

• disrupts cell membrane
• binds to phospholipids
• ex: polymyxin B sulfate= topical, mimics LPS molecule
• -usually toxic= problem w/ osmotic pressure

Answer 8

disruption of cell membrane function

Question 9

Antibody Inhibition of Bac:
-most antibiotics do this
-bacterial ribosome is "different"= similar but different enough then humans
H= L60 and S40=80S
B= L50 and S30= 70S

Answer 9

inhibition of protein synthesis

Question 10

Antibiotic blockage of ribosome cycle…

Answer 10

…

Question 11

Antibody Inhibition of Bac:

• many inhibitors of DNA replication bind to DNA and thus are too toxic for use
• -one exception is metronidazole= inert but can be converted to an active form by anaerobic microbes
• some antibiotics affect DNA gyrase (replication)
• -nalidixic acid
• -quinolones
• some antibiotics inhibit RNA polymerase (transcription)
• -rifamycin
• -usually too toxic

Answer 11

inhibition of nucleic acid synthesis

Question 12

Antibody Inhibition of Bac:

• sulfianilimide= structurally similar to PABA
• PAB must go to folic acid to produce amino acid
• enzyme will be busy w/ sulfamililmide so less folic acid is produced

Answer 12

action as antimetabolites

Question 13

Antibiotics have become over used by:
-
-
-
-

Answer 13

agricultural use
physician misuse
pharmacist misuse
patient misuse

Question 14

Steps in the action of antibiotics:

1. ____penetrates the envelope/wall/membrane
2. transport into cell
3. ____ binds to target
   - -resistance to drugs occurs at each of these steps

Answer 14

drug

drug