Principles of Antibiotic Use

Question 1

What are the two types of targets in selective toxicity?

Answer 1

Unique targets and preferential targets

Question 2

What are two examples of preferential targets?

Answer 2

Bacterial ribosome and DHFR

Question 3

The bacterial cell wall, biosynthetic pathways unique to microorganisms, and unique fungal plasma membrane components are examples of

Answer 3

Unique targets

Question 4

When the concentration of drug can be achieved that inhibits the organism but is below the level of toxicity for human cells, the bacteria is called

Answer 4

Susceptible

Question 5

When a bacteria requires inhibitory or bactericidal concentration that exceeds that which can be achieved safely, that bacteria is called

Answer 5

Resistant

Question 6

What is the Therapeutic Index (TI)?

Answer 6

TI = toxic dose/effective dose

Question 7

Success of treatment of susceptible organisms depends on achieving concentration at the site of infection that is sufficient to

Answer 7

Inhibit growth

Question 8

Host defenses may influence whether an agent is

Answer 8

Bacteriostatic or bactericidal

Question 9

Occurs when the concentration of drug required to kill or inhibit a microbe is greater than the concentration that can be safely achieved

Answer 9

Resistance

Question 10

In general, protein synthesis inhibitors are

Answer 10

Bacteriostatic

Question 11

In general, cell wall-active agents are

Answer 11

Bactericidal

Question 12

Rifampin and quinolones are also

Answer 12

Bactericidal

Question 13

A protein synthesis inhibitor that is classified as bactericidal

Answer 13

Aminoglycosides

Question 14

If MIC is within the therapeutic range of the drug but MBC is not, then the drug is

Answer 14

Bacteriostatic

Question 15

If MBC is within therapeutic range of the drug then the drug is

Answer 15

Bactericidal

Question 16

May be “static” in one growth medium but “cidal” in another

Answer 16

A given drug

Question 17

A drug may also be “static” against one organism, but “cidal” against

Answer 17

Another

Question 18

What are two things that influence the susceptibility of and organism?

Answer 18

1. ) Site of infection

2. ) Local factors

Question 19

An organism that is resistant at plasma concentration may be susceptible at

Answer 19

Urine concentration

Question 20

Can be higher than plasma concentration

Answer 20

Urine drug concentration

Question 21

What are the three general uses of antimicrobial therapy?

Answer 21

Prophylactic, empiric, and definitive

Question 22

Occurs after the onset of symptoms

Answer 22

Empiric treatment

Question 23

Occurs once the pathogen has been isolated

Answer 23

Definitive treatment

Question 24

Highly effective in some clinical settings, but fails to prevent colonization or infection of all microorganisms

Answer 24

Prophylactic therapy

Question 25

Used prophylactically to prevent meningococcal meningitis in people in close contact to a case

Answer 25

Rifampin

Question 26

Used in the prevention of gonorrhea or syphilis after contact with an infected person

Answer 26

Prophylactic therapy

Question 27

What is used prophylactically to prevent recurrent UTIs by E. Coli

Answer 27

TMP-SMX

Question 28

Covers all likely pathogens because the infecting organism(s) has/have not yet been defined

Answer 28

Empiric therapy

Question 29

A single broad-spectrum agent is preferable for

Answer 29

Empiric therapy

Question 30

Requires knowledge of the most likely infecting microorganisms and their susceptibilities to antimicrobial drugs

Answer 30

Empiric therapy

Question 31

Should be taken BEFORE institution of an empiric therapy

Answer 31

Cultures of site of infection and blood

Question 32

Occurs once the infectious organism has been identified and a switch is made to a more specific and narrow-spectrum agent

Answer 32

Definitive therapy

Question 33

A type of empirical therapy of severe infection when the causative organism is unknown

Answer 33

Combination therapy

Question 34

Combination therapy can be used to treat

Answer 34

Polymicrobial infections

Question 35

Combination therapy prevents the emergence of

Answer 35

Resistance

Question 36

What is the frequency of resistance to 1. ) Any 1 drug? 2. ) Any 2 drugs

Answer 36

1. ) 1 in 10^6 cells | 2. ) 1 in 10^12 cells

Question 37

Of particular importance in therapy of TB, especially multi-drug resistant TB

Answer 37

Combination therapy

Question 38

What are the 4 types of combination therapy?

Answer 38

1. ) Synergistic 2. ) Additive 3. ) Indifferent 4. ) Antagonistic

Question 39

When one drug affects the bug such that it is more sensitive to the inhibitory action of another drug, then the drugs are

Answer 39

Synergistiv

Question 40

When the drugs work independently of each other, they are

Answer 40

Additive

Question 41

When the combination of the drugs is no different than if the drugs were used individually, they are

Answer 41

Indifferent

Question 42

When the combination of the drugs is less effective than the individual drugs, the drugs are said to be

Answer 42

Antagonistic

Question 43

Bacteristatic antibiotics frequently antagonize the action of the

Answer 43

Bactericidal ones

Question 44

For example tetracyclines antagonize

Answer 44

B-lactams

Question 45

Bactericidal drugs in combination tend to be

Answer 45

Additive or synergistic

Question 46

The failure to document the causative organism so that a narrow-sectrum agent can be used is a cause of

Answer 46

Anti-biotic misuse

Question 47

The use of drug combinations or drugs with broad spectrum of action is often a cover for

Answer 47

Diagnostic imprecision

Question 48

Substances produced by various species of microorganisms that suppress the growth of other microorganisms and may eventually

Answer 48

Destroy them

Question 49

Each black dot in the phenotypic diversity of resistance profile is 1 of 191

Answer 49

Resistance profiles

Question 50

The resistance profile may reflect the presence of a

Answer 50

Resistance gene