Antibiotics I

Question 1

the bacterial cell wall is composed of what molecule?

Answer 1

peptidoglycan

Question 2

what constitutes gram positivity of bacteria?

Answer 2

thick peptidoglycan wall

Question 3

what constitutes gram negativity of bacteria?

Answer 3

thin peptidoglycan wall

Question 4

what makes up the outer membrane structure of gram negative bacteria?

Answer 4

LPS

Question 5

LPS makes up the outer membrane structures of gram negative or gram positive bacteria?

Answer 5

gram negative

Question 6

what is the effect of LPS on antibiotics?

Answer 6

retards or prevents penetration of bulky, high MW abx (eg erythromycin)

Question 7

what is the effect of the lipid bilayer of the cytoplasmic membrane on antibiotics?

Answer 7

severely hinders penetration of water soluble drugs

Question 8

what component of bacteria retards or prevents penetration of bulky, high MW abx (eg erythromycin)? are these characteristic of gram negative or gram positive bacteria?

Answer 8

LPS

gram negative

Question 9

what component of bacteria severely hinders penetration of water soluble drugs? are these characteristic of gram negative or gram positive bacteria?

Answer 9

lipid bilayer of the cytoplasmic membrane

gram negative AND gram positive

Question 10

what is the effect of hydrophilic pores on antibiotics?

Answer 10

allow penetration of water soluble molecules up to 650 daltons (eg sulfonamides)

Question 11

what components of bacteria allow penetration of water soluble molecules up to 650 daltons (eg sulfonamides)? are these characteristic of gram negative or gram positive bacteria?

Answer 11

hydrophilic pores

gram negative

Question 12

what components of bacteria are used by agents structurally related to nutrients? are these characteristic of gram negative or gram positive bacteria?

Answer 12

nutrient receptor proteins on outer membrane

gram negative

Question 13

what is the effect of nutrient receptor proteins on the outer membrane?

Answer 13

agents structurally related to nutrients use these receptors

Question 14

what is the effect of teichoic acid and teichuronic acid on antibiotics?

Answer 14

strong anion character affects rate of penetration

Question 15

what component of bacteria affects rate of penetration? are these characteristic of gram negative or gram positive bacteria?

Answer 15

teichoic acid and teichuronic acid

gram positive

Question 16

what is the effect of nutrient transport proteins of the cytoplasmic membrane?

Answer 16

facilitate rapid penetration of agents similar in structure

Question 17

what components of bacteria facilitate rapid penetration of agents similar in structure?

Answer 17

nutrient transport proteins of the cytoplasmic membrane

Question 18

what are the three common strategies for killing or inhibiting microorganism growth?

Answer 18

1. disrupt coding / genetic machinery
2. blocking protein synthesis
3. disrupting cell wall or membrane synthesis

Question 19

prophylactic therapy

Answer 19

treatment in absence of infection in order to prevent (eg travel)

Question 20

preemptive therapy

Answer 20

treatment of high risk patients who have become infected but are asymptomatic

Question 21

empirical therapy

Answer 21

treatment of SYMPTOMATIC patient without further testing or confirmation of organism

Question 22

definitive therapy

Answer 22

treatment once pathogenic organism has been identified and appropriate drug identified

Question 23

suppressive therapy

Answer 23

generally a low dose therapy used as secondary prophylaxis

Question 24

treatment in absence of infection in order to prevent (eg travel)

Answer 24

prophylactic therapy

Question 25

treatment of high risk patients who have become infected but are asymptomatic

Answer 25

preemptive therapy

Question 26

treatment of SYMPTOMATIC patient without further testing or confirmation of organism

Answer 26

empirical therapy

Question 27

treatment once pathogenic organism has been identified and appropriate drug identified

Answer 27

definitive therapy

Question 28

generally a low dose therapy used as secondary prophylaxis

Answer 28

suppressive therapy

Question 29

what are the most common drug resistant bacteria?

Answer 29

ESKAPE ``` enterococcus faecium staph aureus klebsiella pneumo acinetobacter baumanni pseudomonas aeruginosa enterobacter species ```

Question 30

what is the therapeutic use for daptomycin?

Answer 30

complicated skin infections bacteremia endocarditis

Question 31

what is a common way to overcome tetracycline sensitivity?

Answer 31

expression of reflux pump

Question 32

what gene mutation results in daptomycin resistance? what is the result?

Answer 32

mprF change in membrane charge - overall net positive charge repels antibiotics that have cationic properties

Question 33

what are the therapeutic uses for tetracycline?

Answer 33

BSA for acne, bronchitis, gonorrhea, syphilis

Question 34

what are the common organisms that are resistant to tetracycline?

Answer 34

neisseria gonorrhoeae e. coli strep pneumo pseudomonas aeruginosa

Question 35

what are the therapeutic uses for metronidazole?

Answer 35

abdominal infections vaginitis c. diff colitis brain abscess

Question 36

what is the mechanism of resistance for metronidazole?

Answer 36

mutation of rdxA gene alters or decreases activation of drug (no longer becomes reduced for activation)

Question 37

what are the therapeutic uses for aminoglycosides (streptomycin)?

Answer 37

combination therapy for endocarditis, tularemia, plague, TB

Question 38

what is the mechanism of resistance for aminoglycosides?

Answer 38

aminoglycoside modifying enzymes chemically modify the antibiotic and alter binding of drug to target

Question 39

what are the therapeutic uses for amoxicillin?

Answer 39

BSA for a variety of infections

Question 40

what is the mechanism of resistance for amoxicillin?

Answer 40

expression of beta lactamase which can hydrolyze the lactam ring of amoxicillin (and other penicillins and cephalosporins)

Question 41

what are the therapeutic uses for trimethoprim and sulfonamides?

Answer 41

combination for UTIs

Question 42

what is the mechanism of resistance for trimethoprim and sulfonamides?

Answer 42

expression of drug resistant enzymes dihydropteroate synthase and DHFR

Question 43

what are the therapeutic uses for vancomycin?

Answer 43

bloodstream infections endocarditis meningitis

Question 44

what is the mechanism of resistance for vancomycin?

Answer 44

substitution on peptidoglycan stem so that agent can no longer bind to target