Antimicrobial

Question 1

First question should always be

Answer 1

Should I be using an antibiotic (and..what am i treating)

Question 2

Three classification of antibiotics

Answer 2

Classification by susceptible organisms
Classification by MOA
Classification by Type

Question 3

Identify the likely pathogen

Answer 3

stains
serologies
culture and sensitivity
site

Question 4

4 basic principles of therapy

Answer 4

know the drug
confirm the presence of infection
identify the likely pathogen
select presumptive therapy
monitor therapeutic response

Question 5

You should see improvement in a patient within

Answer 5

24 to 48 hours

Question 6

phamacokinetics

Answer 6

What the body does to the drug

– Concerned with the time course of antimicrobial
concentrations in the body
– Commonly used to determine dosing regimens

Question 7

Pharmacodynamics

Answer 7

What the drug does to the body.

– Concerned with the relationship between those
concentrations and the antimicrobial effect.
– Increasingly important to design dosing regimens which
counteract or prevent resistance

Question 8

is PK or PD determine dosing

Answer 8

PK

Question 9

MIC

Answer 9

MIC: Minimum Inhibitory Concentration

the LEAST amount of drug that is required to kill or slow the organism

Question 10

MBC

Answer 10

MBC: Minimum Bactericidal Concentration

Minimum that will kill the pathogen

Question 11

Cmax

Answer 11

peak serum level after pt takes the drug

Question 12

Cmin

Answer 12

least amount of drug you will see in the body

trough level

Question 13

AUC

Answer 13

Area under the curve

puts all parameters together

Question 14

Susceptibility testing

Answer 14

MIC

• Primary measure of antibiotic activity

Question 15

– MIC is the lowest antimicrobial

Answer 15

concentration that
prevented prevented visible visible growth of an organism organism after 24 hours
of incubation

Question 16

MIC is a good indicator

Answer 16

of the potency of an antibiotic
– It does not tell us about the time course of
antimicrobial activity

Question 17

Breakpoints

Answer 17

Tells us the MIC/Zone values. Lets us know what which pathogens are susceptible, resistant or somewhat resistant

Question 18

MIC90

Answer 18

tells you that 90% of strains of a particular pathogen are inhibited by this drug

Question 19

PK Parameters help to do what

Answer 19

• Help to quantify the serum level time course of an antibiotic
• Evaluate antibiotic efficacy

Question 20

Three most important PK parameters:

Answer 20

AUC, Cmax, Cmin

Question 21

• Area under the curve is a

Answer 21

plot of concentration concentration of drug

in plasma against time

Question 22

AUC represents

Answer 22

the total amount of drug absorbed by the

body regardless of rate of absorption

Question 23

AUC is usefull in knowing the

Answer 23

g the average concentration over a

time interval

Question 24

How high

Answer 24

peak level vs MIC

Question 25

how long

Answer 25

time above MIC

Question 26

how high for how long

Answer 26

ACU vs MIC

Question 27

Peak/MIC

Answer 27

Cmax divided by MIC - will give you the formula for concentration antibiotic. How high does it need to be to irradicate the pathogen

Question 28

Time>MIC

Answer 28

percentage of dosing interval in which the sum level exceeds the MIC have to have the drug above a certain concerntraion for 40 to 50 % of dosing inverval in order to be effective

Question 29

24 hr-AUC/MIC

Answer 29

24 hour AUC divided by the MIC These drugs have a percisitant antbiotic effect

Question 30

For a concentration (MAX) antibiotic we want to see that

Answer 30

the peak is 10x the MIC

Question 31

for time dosing if you had a drug that was given 10 hours a part how long should the drug be over the MIC

Answer 31

40 to 50% or in this case 4 to 5 hours

Question 32

The new science PK and PD

Answer 32

Is there an antibiotic level in blood that predicts bacterial eradication and clinical success? • If so, what is the optimal profile to maximize bacterial kill?

Question 33

Once PK/PD requirements are known, one can: (3 things)

Answer 33

√ Calculate appropriate doses of new or existing agents – √ Compare antimicrobial activity of existing agents and utilize data in the development of guidelines – √ Determine susceptibility of isolated pathogens

Question 34

AUC/MIC ratioa at least what for gram pos an gram neg

Answer 34

25-30 pos | 125 neg

Question 35

Examples of Peak MIC drugs

Answer 35

aminoglycosides

Question 36

examples of time dependent drugs

Answer 36

beta-lactums clindamycin erythromycin linezolid

Question 37

24-AUC/MIC drug examples (persistant)

Answer 37

azithromycin quinolones vancomycin

Question 38

Examples of Multi-Drug Resistant Organisims

Answer 38

Strep pneumonaie M hi illi Methicillin R i es stance S h tap aureus (MRSA CA (MRSA,CA‐MRSA) – Vancomycin resistant enterococci (VRE) – Some Gram negative organisms (MDR‐GNB)

Question 39

Factors that Increase Antibiotic | Resistance

Answer 39

``` • Overuse of Antibiotics • Inappropriate antibiotics • Low dose… inadequate levels… subinhibitory exposure • Day Care and crowded living ```

Question 40

Mechanisms of Resistance: | 4 main types

Answer 40

* 1. Decreased Permeability * 2. Antibiotic Efflux Pump * 3. Drug Inactivation * 4. Altered Target Site

Question 41

Decreased permaiblity

Answer 41

lack of purions to get into the cell

Question 42

Drug Efflux

Answer 42

eflux pumps, pump antibiotic out of the cell after they enter it

Question 43

Drug inactivation

Answer 43

Enzymes inactivate the antibiotic

Question 44

Altered Target

Answer 44

Changes that occur in the ribosomes

Question 45

Beta‐lactamase

Answer 45

– Enzymes which destroy Penicillins and their | relatives

Question 46

Beta‐Lactamase Inhibiting Compounds

Answer 46

Beta‐lactam antibiotics to which another component (e.g. clavulanic acid added to Amoxicillin) has been added to counteract the beta‐lactamase

Question 47

Cross-resistance

Answer 47

Genetic information may be passed from one | bacteria to another

Question 48

Four types of cross resistance

Answer 48

– Mutation – Conjugation – Transduction – Transformation

Question 49

Conjugation

Answer 49

one bacteria shares dna with another bacteria

Question 50

transduction

Answer 50

viral bacterial eats bacteria and shares DNA with it

Question 51

Transformation

Answer 51

bacterial can incorporate dna from another organisim that is in the same enviornment. Bridge is not needed in this type