Exam 1 - Cushman (Lecture 2)

Question 1

cephamycins are ____ _____ cephalosporins

Answer 1

2nd gen

Question 2

Explain the difference between bacteriostatic and bactericidal

Answer 2

baceriostatic prevent bacteria from growing and bactericidal actively kill bacteria (and prevent new growth of it)

Question 3

Cefotetan has (broad/narrow) spectrum of activity

Answer 3

broad

Question 4

Cefotetan has a similar reaction to ____ as ____

Answer 4

ethanol, disulfuram

Question 5

polar molecules are (more/less) likely to pass through porins

Answer 5

more

Question 6

Which are more reactive and why: carbapenems or penicillins?

Answer 6

carbapenems because sulfur in penicillin is replaced by methylene, which is smaller and produces more ring strain

Question 7

imipenem administered with _____ has (broad/narrow) antibioitic activity

Answer 7

cilastatin, broad
-active against gram (-) and (+)
-called “magic bullet” and should be avoided unless last option or serious infection

Question 8

Aztreonam inspired by ____

Answer 8

monobactams

Question 9

Aztreonam only works on gram (-/+)?

Answer 9

gram (-)

Question 10

aztreonam place in therapy

Answer 10

used in serious gram (-) infections, particularly those that are penicillin resistant organism acquired in hospitals

Question 11

only cephalosporin reported to have cross allergenicity with penicillins

Answer 11

ceftazidime
-oxime ether group makes it resistant to hydrolysis by B-Lacatamases

Question 12

Cephamycin example

Answer 12

cefotetan

Question 13

carbapenem example

Answer 13

imipenem (can be used with cilastatin)

Question 14

monobactam example

Answer 14

aztreonam

Question 15

glycopeptide example (only two in clinical use)

Answer 15

vancomycin
teicoplanin

Question 16

vancomycin works on gram (-/+)? Why?

Answer 16

gram (+), vanco is too big to fit through porins in gram (-) cell wall

Question 17

mechanism of vancomyin

Answer 17

D-Ala-D-Ala binds to peptidoglycan precursor before cross-linking. Vanco has high affinity for this substrate, which inhibits the transpeptidase reaction required for cross-linking

Question 18

vanco is (bactericidal/bacteriostatic) and active against gram (-/+)

Answer 18

bactericidal, gram (+)

Question 19

susceptible strains (to vanco) usually have MIC _ micrograms/mL

Answer 19

4

Question 20

Why did VREs become more common in europe?

Answer 20

Avoparcin, a glycopeptide antibiotic, was used in livestock. Once banned, VRE became less common. The mechanism of resistance appeared to be because of a mutation of the peptidoglycan cell wall precursor from D-Ala-D-Ala to D-Ala-D-Lactate and vancomycin has 1000x less affinity for the D-Ala-D-Lactate precursor, leading to linkage between the D-Ala-D-Lactate precursor and the peptidoglycan precursor, which allowed the transpeptidase reaction to occur.

Question 21

vanco is used IV except in the case of: _____

Answer 21

C. diff.

Question 22

vanco is used to treat what common resistance infection?

Answer 22

MRSA (methicillin resistant staphylococcus aureus

Question 23

describe vanco toxicity and SE

Answer 23

hypersensitivity rxn: red rash on skin and potential anaphylaxis
nephrotox. (rare)
ototox. (rare)

Question 24

lipoglycopeptide antibiotics examples

Answer 24

oritavancin
telavancin
dalbavancin

Question 25

oritavancin is active against gram (-/+) bacteria and is (broad/narrow) spectrum

Answer 25

gram (+), active against a broad spectrum, including MRSA

Question 26

telavancin is active against gram (-/+) infections, including ____

Answer 26

gram (+), MRSA

Question 27

dalbavancin is active against gram (-/+) infections, including ____ and ____

Answer 27

gram (+), MRSA, MRSE

Question 28

half lives of vanco tela dalba orita

Answer 28

4-6h 7-9h 204h 245h

Question 29

streptogramin examples

Answer 29

quinupristin dalfopristin

Question 30

Synercid is comprised of 30% _____ and 70% _____

Answer 30

quinupristin, dalfopristin

Question 31

quinupristin and dalfopristin are (bacteriostatic/bactericidal/both)

Answer 31

bacteriostatic (together as synercid or alone)

Question 32

Synercid is bactericidal against strains of _______ -_____ and ______-_______ staphylococci

Answer 32

methicillin-susceptible and methicillin-resistant

Question 33

Synercid is bacteriostatic against _______

Answer 33

Enterococcus faecium

Question 34

Synercid clinical uses

Answer 34

IV for tx of: 1. Vancomycin resistant Enterococcus faecium bacteremia (but not Enterococcus faecalis). Certain Enterococcus faecium bacteremia are resistant to all other antibiotics 2. skin infections caused by MRSA 3. vancomycin resistant Enterococcus faecium urinary tract infections

Question 35

quinupristin resistance mechanism (1)

Answer 35

adenine methylation of A2058 in the 23S rRNA -causes Synercid to be bacteriostatic instead of bactericidal at normal dose

Question 36

quinupristin resistance mechanism (2)

Answer 36

efflux pumps and bacterial metabolism

Question 37

List Synercid tox.

Answer 37

none known

Question 38

Synercid SE

Answer 38

pain and inflammation at injection site N/D rash muscle weakness

Question 39

list the one major drug interaction of streptogramins

Answer 39

inhibit CYP3A4, which metabolizes a long list of drugs

Question 40

oxazolidinone examples

Answer 40

Linezolid Tedizolid (2nd gen)

Question 41

Linezolid MOA

Answer 41

Inhibit protein synthesis at the 50S ribosomal subunit. Normally, 50S subunit associates with fMet-tRNA and a complex comprised of the 30S ribosomal subunit and mRNA to form the functional 70S initiation complex. Linezolid blocks 50S from becoming 70S.

Question 42

Linezolid used to treat:

Answer 42

1.vancomycin resistant Enterococcus faecium 2. nosocomial pneumonia caused by methicillin-resistant strains of Staph. aureus 3. skin infections caused by methicillin-resistant strains of Staph. aureus

Question 43

Linezolid is available as (oral/IV/both/neither)

Answer 43

both

Question 44

when should linezolid be used?

Answer 44

only to treat or prevent infections that are proven or strongly suspected to be caused by multiple drug resistant Gram(+) bacteria or when pts are allergic to alternative therapies

Question 45

resistance to linezolid associated with

Answer 45

G to U substitution in the peptidyl transferase center of 23S rRNA at position 2576

Question 46

SE of linezolid

Answer 46

NVD HA tongue discoloration oral candidiasis (thrush) reversible myelosuppresion

Question 47

weekly monitoring during linezolid

Answer 47

CBC

Question 48

major linezolid drug interaction

Answer 48

moderately potent, reversible, nonselective inhibitor of monoamine oxidase -caution in adrenergic and serotonergic agents -caution in high tyramine containing foods

Question 49

Tedizolid uses

Answer 49

treats acute bacterial skin and skin structure infections

Question 50

(tedizolid/linezolid) is more potent against MRSA

Answer 50

tedizolid