Bacterial resistance

Question 1

How do bacteria inactive drugs?

Answer 1

They produce enzymes that destroy them

Question 2

How are beta-lactam AB inactivated?

Answer 2

Cleavage of Beta-lactam ring

Question 3

How are aminoglycoside AB inactivated?

Answer 3

Modified via acetylation, adenylation, or phosphorylation

Question 4

How can bacteria decrease accumulation of AB?

Answer 4

1. Mutate or lose porin channels which AB use to enter cells

2. Increase efflux of AB

Question 5

What causes resistance to bind to fluoroquinolones?

1. Mutations in DNA gyrase (A, B subunits
2. Mutation in rpoB encoding beta subunit of RNA polymerase
3. Resistance to beta-lactams
4. Alterations in cross-linking of peptidoglycan
5. Decreased access to ribosomes due to presence of ribosomal protective proteins (tet genes)

Answer 5

1. Mutations in DNA gyrase (A, B subunits

Question 6

What causes resistance to bind to Rifampin?

1. Mutations in DNA gyrase (A, B subunits
2. Mutation in rpoB encoding beta subunit of RNA polymerase
3. Resistance to beta-lactams
4. Alterations in cross-linking of peptidoglycan
5. Decreased access to ribosomes due to presence of ribosomal protective proteins (tet genes)

Answer 6

2. Mutation in rpoB encoding beta subunit of RNA polymerase

Question 7

What causes resistance to bind to penicillin?

1. Mutations in DNA gyrase (A, B subunits
2. Mutation in rpoB encoding beta subunit of RNA polymerase
3. Resistance to beta-lactams
4. Alterations in cross-linking of peptidoglycan
5. Decreased access to ribosomes due to presence of ribosomal protective proteins (tet genes)

Answer 7

3. Resistance to beta-lactams

Question 8

What causes resistance to bind to Vancomycin?

1. Mutations in DNA gyrase (A, B subunits
2. Mutation in rpoB encoding beta subunit of RNA polymerase
3. Resistance to beta-lactams
4. Alterations in cross-linking of peptidoglycan
5. Decreased access to ribosomes due to presence of ribosomal protective proteins (tet genes)

Answer 8

4. Alterations in cross-linking of peptidoglycan

Question 9

What causes resistance to bind to Tetracycline?

1. Mutations in DNA gyrase (A, B subunits
2. Mutation in rpoB encoding beta subunit of RNA polymerase
3. Resistance to beta-lactams
4. Alterations in cross-linking of peptidoglycan
5. Decreased access to ribosomes due to presence of ribosomal protective proteins (tet genes)

Answer 9

5. Decreased access to ribosomes due to presence of ribosomal protective proteins (tet genes)

Question 10

How could you treat resistant infections due to inactivation of drug?

Answer 10

Incorporate Beta-lactamase inhibitors w/ Beta-lactams

Question 11

How does incorporating Beta-lactamase inhibitors w/ Beta-lactams help treat resistant infections due to inactivation help?

Answer 11

Prevents hydrolysis of antibiotic

Question 12

Clavulanic MOA?

Answer 12

Irreversible binding of Beta-lactamse enzyme (Suicide inhibitor)

Question 13

How do you treat resistant infections due to modification of drug?

Answer 13

Novel chemical synthesis of aminoglycoside to prevent modifications by bacterial enzymes

Question 14

What is an analog to semisynthetic tetracycline derivative minocycline that is not affected by ribosomal protective + tetracycline-specific efflux?

Answer 14

Tigecycline

Question 15

How would you get around efflux mechanisms?

Answer 15

1. Use Tigecycline

2. Use efflux inhibitors (especially useful w/ fluorquinolones)

Question 16

What is an alternate if porin mutations exist?

Answer 16

Use siderophore uptake systems (iron uptake system)

Question 17

How do you get around a drug not being able to bind to target/reduced affinity to binding spot on bacteria?

Answer 17

Alter AB structure to bind or restore affinity to target while retaining antimicrobial activity