Test 3: 37 antibiotics part 2

Question 1

how does B lactams work

Answer 1

inhibit transpeptidase enzymes from forming crosslinks between peptidoglycans in the cell wall

Question 2

peptidoglycan is a rigid mesh of cross linked —

Answer 2

glycopeptides

TPase forms cross bridges between chains

β lactam antibiotics (penicillin, cephalosporins) inhibt TPase from working

Question 3

some bacteria make — that makes them resistant to penicillin

Answer 3

β lactamase

acts as a PBP (peniciilin binding protein)

will bind to penicillin and change its structure so it can not bind to Transpeptidase enzyme and stop crosslinking of PG in the cell wall

Question 4

how to prevent βlactamase resistance

Answer 4

some semi synthetic penicillins are resistant (dicloxacillin and oxacillin)

synthetic β lactams such as Monobactam

use combo of drugs (clavamox)

Question 5

how does clavamox prevent resistance by β lactamases

Answer 5

combo of
Amoxicillin (SS, broad spectrum, β-lactamase sensitive)

Clavulanic Acid (β-lactamase inhibitor)

Question 6

vancomycin

Answer 6

bactericidial- attack cell wall ( D-Ala and inhibit cross linking)

gram + only

2nd line defense against peniciilin resistant S. aureus

poorly absorbed- given IV

Question 7

— binds to the free D-Ala-D-Ala end of the Pentapeptide and inhibits cross-linking by steric hindrance.

Answer 7

Vancomycin- gram + bactericial antibiotic

Vancomycin does not affect the catalytic activity of the transpeptidase.

Question 8

mechanism of action for bacitracin

Answer 8

bactericial (Gram + > Gram -)

Prevents dephosphorylation of a Lipid carrier during glycopeptide transfer through the cell membrane required for cell wall synthesis

poorly absorbed in the gut (topical use)

Question 9

bacitracin prevents — of a Lipid carrier during glycopeptide transfer through the cell membrane required for cell wall synthesis

Answer 9

dephosphorylation

prevents P from breaking off and opening P up for binding to chains and moving them out onto the cell surface

bactericial (gram +» gram -)

Question 10

cycloserine is used to fight —

Answer 10

Mycobacterium tuberculosis and Mycobacterium avium

Question 11

how does cycloserine work

Answer 11

Cycloserine prevents addition of the two terminal D-Alanines to the Tripeptide side chain attached to NAM

Question 12

Cycloserine prevents addition of the — to the Tripeptide side chain attached to NAM

Answer 12

two terminal D-Alanines

cycloserine- broad spectrum (Mycobacterium tuberculosis)

Question 13

The — block cross-linking by inhibiting the
transpeptidase.

Answer 13

β-lactams

penicillin + cyclosporins

Question 14

Combat β lactamase by using — drugs or by combinations of drug

Answer 14

Semi- or fully synthetic β- lactamase-resistant

Question 15

Vancomycin inhibits cross-linking by —

Answer 15

steric hindrance

binds to DAla and prevents TPase (transpeptidase) from forming cross bridges

Question 16

— inhibits dephosphorylation of the carrier lipid in the cell wall

Answer 16

Bacitracin

bactericidal: gram +» Gram -

Question 17

Cycloserine prevents — addition

Answer 17

D-Ala-D-Ala

Cycloserine prevents addition of the two terminal D-Alanines to the Tripeptide side chain attached to NAM

bactericidial broad spectrum (Mycobacterium tuberculosis)

Question 18

Fluoroquinolones (inhibit — synthesis)

Answer 18

DNA

Question 19

Rifamycins (inhibit — synthesis)

Answer 19

RNA

Question 20

how is RNA made

Answer 20

RNA polymerase binds to DNA and makes RNA

Question 21

— allows for unwinding of DNA

Answer 21

topoisomerase II (DNA gyrase)

Question 22

what are some fluroquinolines

Answer 22

Enrofloxacin, Difloxacin, Orbifloxacin and Marbofloxacin.

bactericidal ( broad gram - spectrum, narrow Gram + (staph))

inihibit DNA synthesis

Question 23

mechanism of action for fluoroquinolines

Answer 23

Fluoroquinolones bind to the nicked DNA and TI-II (Topoisomerase II/ DNA gyrase) And prevent the re-sealing of DNA and subsequent replication And re-supercoiling.

Enrofloxacin, Difloxacin, Orbifloxacin and Marbofloxacin.
Bactericidal (Broad G- Spectrum; Selected G+ (e.g. some Staph))

Question 24

mechanism of action for rifamycin

Answer 24

Binds and blocks bacterial RNA polymerase

bactericial
Broad G +(mycobacterium), narrow Gram - (brucella)
can interact with other meds like warfarin or steroids

Question 25

mechanism of action for novobiocin

Answer 25

Inhibits DNA Gyrase (Topoisomerase-II) (Potency&raquo_space; Fluoroquinolones)

narrow spectrum Gram +

Question 26

when to use metronidazole

Answer 26

anaerobic infections: clostridium

protozoal infections: giardia

rapid bactericial
prodrug that is activated in anaerobes and prevents DNA synthesis

Question 27

how does metronidazole work

Answer 27

prodrug is changed by ferredoxin in anaerobes to generate active metabolit

Binds to DNA and causes its fragmentation - prevents DNA synthesis

anaerobic infections: clostridium
protozoal infections: giardia

Question 28

— is only effective against obligate anaerobic bacteria

Answer 28

metronidazole

prodrug that is turned into metabolite that prevents DNA synthesis by binding and causing fragmentation of DNA

Question 29

The — bind to nicked DNA and inhibit DNA Gyrase (Topoisomerase II) that is only present in bacteria.

Answer 29

Fluoroqinolones

Question 30

— block the activity of RNA polymerase and prevent RNA synthesis.

Answer 30

Rifamycins

Question 31

— binds to and inactivates Topoisomerase-II by preventing ATP binding

Answer 31

Novobiocin

Question 32

— is a prodrug that generates free radicals in anaerobic bacteria. These radicals fragment the bacterial DNA

Answer 32

Metronidazole

Question 33

what are some drugs that inhibit protein synthesis by disrupting bacterial ribosomal function .

Answer 33

Aminoglycosides, Tetracyclines, Puromycin, Macrolides, Lincosamides, Chloramphenicol