Antibiotic Resistance Mechansims

Question 1

Bacteriocidal antibiotic

Answer 1

Kills the bacteria

Question 2

Bacteriostatic

Answer 2

Inhibits bacterial growth

Question 3

Natural antibiotics

Answer 3

Secondary metabolic products from microbes

Question 4

6 key strategies/targets of antibiotics

Answer 4

• Cell wall synthesis
• DNA replication
• RNA synthesis
• Protein synthesis
  5. Folic acid synthesis
• Membrane disruption

Question 5

Transpeptidase

Answer 5

Cross links peptide chains of peptidoglycan cell wall using D-Ala D-Ala motif

Question 6

Cell wall synthesis inhibitor

Answer 6

Penicillin

Question 7

DNA gyrases

Answer 7

Reseal the bacterial DNA to begin DNA synthesis

Question 8

DNA topoisomerases

Answer 8

Cut the bacteria to unwind supercoils

Question 9

Fluoroquinolones

Answer 9

Bind to DNA gyrases, cause lethal DNA breaks

Question 10

RNAP

Answer 10

Causes chain elongation in transcription

Question 11

Rifamycin

Answer 11

Inhibits RNAP, stops RNA chain elongation

Question 12

Tetracycline, clindamycin, chloramphenicol, neomycin, erythromycin

Answer 12

Inhibits protein synthesis

Question 13

Folic acid synthesis

Answer 13

Synthesized de novo from PABA, needed for purine synthesis

Question 14

Sulfanomides

Answer 14

Inhibit Folic acid synthesis

Question 15

Daptomycin

Answer 15

Interrupts ion gradient of gram positive bacteria

Question 16

Colistin

Answer 16

Membrane disruption of gram negative bacteria

Question 17

How do bacteria resist the action of antibiotics? (5)

Answer 17

• Inactivating the antibiotic
• Modifying or replacing target
• Remove abx from cell 9multi-drug resistance)
• Prevent uptake of antibiotic
• Develop per sister populations (neither grow nor die during antibiotic exposure

Question 18

Beta lactamase

Answer 18

Cleave beta lactam ring of penicillin

Question 19

Vancomycin

Answer 19

Binds to D-Ala D-Ala to prevent transpeptidase activity

Question 20

Vancomycin resistance

Answer 20

Replaces D-Ala D-ala with D-ala D-lactate, which vancomycin can’t bind to

Question 21

2 types of effluent transporters

Answer 21

Single component or multi component

Question 22

Prevention of antibiotic uptake (4)

Answer 22

• Decrease in OMP gene expression (gram -)
• Increase thickness of peptidoglycan (gram +)
• Capsule formation
• Biofil, production

Question 23

Persister population

Answer 23

Not genetic mutants, metabolically inert “survive and advance”