Antibacterials

Question 1

What is the morphology of streptococci?

Answer 1

Gram positive cocci in chains

Question 2

What is the morphology of staphylococci?

Answer 2

Gram positive cocci in grape-like clusters

Question 3

True or false: all bacteria have a cell wall consisting of peptidoglycan

Answer 3

True

Question 4

What is peptidoglycan?

Answer 4

a macromolecule composed of peptides and sugars

Question 5

What does LPS consist of?

Answer 5

Phospholipid and polysaccharides

Question 6

What is the major difference between eukaryotic cell membranes and prokaryotic?

Answer 6

Prokaryotes have sterols

Question 7

What bacteria are catalase positive?

Answer 7

Staph

Question 8

Catalase positive, coagulase positive = ?

Answer 8

Staph aureus

Question 9

What is the most common agent for UTIs?

Answer 9

E.coli

Question 10

Clostridium is gram positive or negative?

Answer 10

Positive

Question 11

What agar is needed to grow Neisseria gonorrhoeae?

Answer 11

Chocolate agar

Question 12

What is the effect of LPS on antibiotics?

Answer 12

Retards or prevents penetration of bulky, high molecular weight abx

Question 13

What is the effect of the lipid bilayer of the cytoplasmic membrane on abx?

Answer 13

Penetration of water soluble drugs is severely hindered

Question 14

What is the effect of hydrophilic pores on abx?

Answer 14

Allows penetration of water soluble molecules

Question 15

What is the effect of nutrient receptors proteins on the outer membrane of bacteria on abx?

Answer 15

Sideomycins utilize these natural receptors

Question 16

Macrolides work well against what type of bacteria?

Answer 16

Gram positive, generally

Question 17

What is the function of teichoic acid on abx?

Answer 17

Strong anionic character of these will affect the rate of penetration

Question 18

What is the effect of the gram positive lipid bilayer?

Answer 18

Affect the rate of penetration of lipophilic drugs

Question 19

What is the effect of nutrient transport proteins on Gram positive bacteria and abx?

Answer 19

Facilitate rapid penetration of agents similar in structures

Question 20

What is the EC50 for abx?

Answer 20

Inhibitory concentration at which 50% of the organisms are killed or stop growing

Question 21

What is the Emax for abx?

Answer 21

Maximum microorganism death or impaired growth

Question 22

What are the three major ways to inhibit bacteria?

Answer 22

1. Disrupt coding/genetic machinery
2. Block protein synthesis
3. Disrupt exterior of the cell

Question 23

True or false: bactericidal and bacteriostatic effect can sometimes be dose-dependent

Answer 23

True

Question 24

Is tetracycline a broad or narrow spectrum abx?

Answer 24

Broad

Question 25

What is pre-emptive therapy?

Answer 25

Treatment of high-risk patients that have become infected, but are asymptomatic

Question 26

What is prophylactic therapy?

Answer 26

treatment without infection

Question 27

What is empirical therapy?

Answer 27

Treatment of a symptomatic patient without further testing or confirmation of the organism

Question 28

What is definitive therapy?

Answer 28

Treatment once the pathological organism has been identified and appropriate drug identified

Question 29

What is suppressive therapy?

Answer 29

Generally a low dose therapy used as a secondary prophylaxis.

Question 30

What is the difference between transduction and transformation?

Answer 30

***

Question 31

What are the 6 drug resistant organisms?

Answer 31

``` Enterococcus faecium Staph aureus Klebsiella pneumoniae Acinetobacter baumannii Pseudomonas aeruginosa Enterobacter species ``` (ESKAPE)

Question 32

What is the therapeutic use of daptomycin?

Answer 32

Complicated skin infection, endocarditis

Question 33

What is the MOA of resistance to daptomycin?

Answer 33

Specific gene mutation (mprF) that results in a change in membrane charge (add lysine). There is an overall increase in the net positive charge which will repel the abx with cationic properties

Question 34

What is the therapeutic use of tetracycline?

Answer 34

Broad specturm abx

Question 35

What is the MOA of resistance to tetracycline?

Answer 35

Expression of an efflux pump

Question 36

What is the therapeutic use of metronidazole?

Answer 36

Abdominal infections, clostridium difficile

Question 37

What is the abx of choice for C.diff?

Answer 37

Metronidazole or vanco if bad

Question 38

What is the MOA of resistance to metronidazole?

Answer 38

Metronidazole needs to be reduced to generate ROS. Mutations in rdxA gene (oxygen-sensitive nitroreductase) alters or decreases activation of the drug

Question 39

How is metronidazole a prodrug?

Answer 39

Needs to be reduced to generate ROS

Question 40

What is the MOA of resistance to aminoglycosides?

Answer 40

Aminoglycoside-modifying enzymes chemically modifies the abx and alters binding of the drug to its target

Question 41

What type of abx is amoxicillin?

Answer 41

Beta-lactam broad spectrum

Question 42

What is the MOA of resistance with amoxicillin?

Answer 42

Expression of the enzyme beta lactamase which can hydrolyze the lactam ring of amoxicillin and render the compound ineffective

Question 43

What is the therapeutic use of trimethoprim and sulfonamides?

Answer 43

UTIs

Question 44

What is the MOA of resistance to trimethoprim and sulfonamides?

Answer 44

Expression of the drug insensitive enzymes dihydropteroate synthase and dihydrofolate reductase

Question 45

What is the drug that can inhibit beta lactamase?

Answer 45

Augmentin (clavulanic acid)

Question 46

What is the therapeutic use of vanco?

Answer 46

Bloodstream infections

Question 47

What is the MOA of resistance to vanco?

Answer 47

Substitution of the peptidoglycan stem so that agent can no longer bind to the target

Question 48

What is the MOA of trimethoprim and sulfonamides?

Answer 48

Sulfa inhibits dihydrofolate synthase

Question 49

What is the MOA of trimethoprim?

Answer 49

Inhibits dihydrofolate reductase

Question 50

What is the MOA of vanco?

Answer 50

Binds to d-ala in the growing peptidoglycan chain, causing steric hindrance