Lecture 20: Antimicrobial Resistance

Question 1

Intrinsic resistance

Answer 1

Due to structural and functional traits present in all members of a given bacterial species or group

Question 2

Examples of intrinsic resistance

Answer 2

• Reduced permeability of outer membrane

- Reduced affinity of the target

Question 3

Two ways bacteria acquire resistance

Answer 3

• Mutation

- Horizontal gene transfer

Question 4

Three types of horizontal gene transfer

Answer 4

• Transformation
• Transduction
• Conjugation

Question 5

Transformation

Answer 5

Uptake of free DNA

Question 6

Transduction

Answer 6

Transfer mediated by phage delivery

Question 7

Conjugation

Answer 7

Transfer cell-to-cell contact

Question 8

Salmonella is resistant to

Answer 8

• Cephalosporins

- Fluoroquinolones

Question 9

Campylobacter is resistant to

Answer 9

• Macrolides

- Fluoroquinolones

Question 10

Three emerging resistant bacteria in animals

Answer 10

• MRSA
• MRSP
• ESBL producers

Question 11

What is MRSA?

Answer 11

• Methicillin resistant Staph. aureus

- Acquired resistance gene mecA which encodes a penicillin binding protein PBP2A with low affinity to most b-lactams

Question 12

What is MRSP?

Answer 12

• Methicillin resistant Staph psuedointermedius

- Acquired mecA

Question 13

Approx. 70% of cases of MRSP are

Answer 13

Skin and wound post-surgical infections acquired in the clinic

Question 14

Are MRSP infections in humans common/

Answer 14

Nope, and are generally only due to transmission from household pets

Question 15

What is ESBL?

Answer 15

• Extended spectrum beta lactamase

- Enzyme hydrolizing/inactivating most B-lactams that are produced by gram negative bacteria

Question 16

True ESBL’s are susceptible to

Answer 16

B-lactamase inhibitors

Question 17

Three main classes of ESBL’s

Answer 17

• CTX-M
• SHV
• TEM

Question 18

Each class of ESBL is classified into variants based on

Answer 18

Sequence identity

Question 19

The frequency of each variant of ESBL depends on

Answer 19

Host and geographical factors

Question 20

Most common type of ESBL in animals is

Answer 20

CTX-M-1

Question 21

The widespread false ESBL is

Answer 21

CMY-2

Question 22

ESBL plasmid transmission is common in what group of humans?

Answer 22

farm workers

Question 23

Whenever possible, you should use what to treat MRSP?

Answer 23

Topical treatments

Question 24

Three drugs used to manage unusual infections of MRSP and ESBL

Answer 24

• Chloramphenicol
• Rifampicin
• Nitrofurantoin