General

Question 1

What factors can change the effectiveness of an antimicrobial?

Answer 1

organism involved
in-vitro susceptibility test
location of infection

Question 2

what formulations exist?

Answer 2

oral, IV, IV regional perfusion, PMB beads (slow release)

Question 3

what is important to keep in mind during administration to food animal?

Answer 3

injection site reactions and trim losses

Question 4

What do successful therapies require?

Answer 4

sufficient dose to slow down enough for immune system to take over

Question 5

What is the exception to the typical assumption that high plasma concentrations are advantagous?

Answer 5

new macrolides

- low plasma concen but extremely high tissue concentrations

Question 6

What is MIC, MBC, MPC?

Answer 6

minimum inhibitory concentrations (used in practice)
minimum bacteriocidal concentration
Mutant prevention concentration (MIC of toughest bacteria)

Question 7

What are you determining with susceptibility testing?

Answer 7

whether MIC is >< or = to local drug concentration

- based on plasma

Question 8

What types of susceptbility testing can you do?

Answer 8

microdiltuion
disk diffusion
E-test

Question 9

What does susceptability testing not account for?

Answer 9

host immune system, drug distribution, concentration at the site, bacterial growth and inoculum size, mixed infection, infection environment, antimicrobial, synergism

also
- local application
BNPH (superficialkeratitis)

Question 10

What are the clinical laboratory standards institute (CLSI)?

Answer 10

establish standards by relating concentration to MIC

- breakpoints specific to species

Question 11

What are the two categories of antimicrobials?

Answer 11

Bacteriocidal

• MBC:MIC = <4-6
• able to obtain concentrations to kill 99.9%

Bacteriostatic

• MBC:MIC = large
• not safe to administer enough to kill 99.9%

drugs are consistently both of these
irrelevant in vet practice

Question 12

What is Post antibiotic effect (PAE)?

Answer 12

bacterial growth remains supressed after the antimicrobial has dropped belo wMIC

dependent on combo and multidrug interaction

Question 13

How can we further optimize antimicrobials usage?

Answer 13

PK - what the drug does to body (ADME)

PD - what drug does to bacteria

Question 14

What are the parameters for PK and PD on a graph

Answer 14

PK: AUC, Cmax, T1/2, Cis
PD: MIC

Question 15

What does the concentration dependent graph look like?

Answer 15

Cmax:MIC or AUC:MIC

- higher peak , more AUC

Question 16

What does the time dependent graph look like?

Answer 16

T > MIC

- amount of time plasma remains over MIC (long as possible)

Question 17

How do we determine whether an antimicrobial is time or concentration dependent?

Answer 17

Kill curves

Question 18

How do we read kill curves?

Answer 18

Dose
- the higher the drug concentration/MIC the steeper the kill curve the more cidal effect on bacteria

Time
- dose does not change the kill curve that much, but duration

Question 19

What is the concentration dependent approach to therapy?

Answer 19

MORE IS BETTER

Question 20

What is the time dependent approach to therapy?

Answer 20

GIVE MORE OFTEN

• harder with client complience
• need long acting