ISB 2 - Vanc résistance

Question 0

E.g. Of bacteria with high level van resistance 2

And 2 low level

Answer 0

E faecalis
E faecium

Low:
E. Gallinarum
E. Casseliflavus

Question 1

How do enterococcus become vanc resistant (VRE)

Answer 1

Plasmid or transposons encoded resistance - (this is higher level resistance as opposed to lower level natural resistance)

Question 2

Where does VRE occur

Answer 2

Nosocomial infections ( and some factor chickens)

Question 3

What do we use to treat VRE

Answer 3

Linezolid

Question 4

How many difference vanc resistances are there?

Answer 4

6

Question 5

What is the difference between vanc resistance VAN-A, B and C

Answer 5

A is resistant to vanc and teicoplanin
B is resistant to vanc (sensitive to teicoplanin)
C is partially resistant to vanc (sensitive to teicoplanin)

Question 6

What is the most recent antibiotic

Answer 6

Linezolid

Question 7

Under normal conditions vanc binds to

Answer 7

D-Ala-D-Ala

Question 8

In vanc resistance the target site changes to…

This results in…

Answer 8

D-Ala-D-Lactate
(from D-Ala-D-Ala)
O is substituted for NH

Results in loss of one H bond (4/5) being possible between vanc and target site
1000x decrease in affinity

Question 9

What happens in a D-Ala-D-Ser mutation?

Answer 9

D-Ala-D-Ala is replaced with D-Ala-D-Ser

Results in 6x decrease of affinity of vanc for target, possibly due to steric hinderance

Question 10

Cilastatin is added to formulations of imipenem to…. 2

Answer 10

Peptidase inhibitor (that break the ß-lactam) and alters the PK

Question 11

What is in coamoxiclav

Answer 11

Amoxicillin and clavulanate

Question 12

Pipericillin is thought to be a better………. Because it has more h bonds

Answer 12

Substrate mimic