inhibitors of cell wall synthesis part 1

Question 1

importance of bacterial cell wall? (4points)

Answer 1

Surround and protect the cell
Provides rigidity 
Act as an attachment site 
Resist pressure changes 
If cell wall is lost, the cell will burst and will die

Question 2

what is the role of the R group in penicillins?

Answer 2

determines stability to enzymes and acids, the antibacterial spectrum and hypersensitivity.

Question 3

Name the enzyme that penicillins activate, which is responsible for the breakdown of peptidoglycans

Answer 3

autolysin

Question 4

name the components of gram - bacterial cell wall

Answer 4

lipopolysaccharide
outer membrane
peptidoglycan
cytoplasmic membrane

Question 5

name the components of gram + bacterial cell wall

Answer 5

peptidoglycan

cytoplasmic membrane

Question 6

Are penicillins effect against mircroorganisms devoid of a cell wall?

Answer 6

no

Question 7

name the natural penicillins

Answer 7

penicillin G (benzyl penicillin)
penicillin v (phenoxymethyl penicillin)
procaine penicillin (benzyl penicillin procaine)
benzathine penicllin

Question 8

all natural penicillins are unstable? true or false

Answer 8

true

Question 9

penicillin G is used to treat

a. meningitis in children
b. nosocomial infections
c. nephrotoxcicity

Answer 9

meningitis in children

Question 10

Name a drug effective against primary and secondary syphilis

Answer 10

penicllin

Question 11

in gonorrhoea, penicillin resistant strains are treated with which 2 drugs?

Answer 11

ceftriaxone with septinomycin as a backup

Question 12

why is penicllin G started initially and penicillin V continued when the clinical symptoms disappear?

Answer 12

such is done because the absorption of penicillin V is unpredictable

Question 13

penicillin V is effective against anaerobes? true or false

Answer 13

true

Question 14

name the antibacterial spectrum of penicllin g and penicillin v

Answer 14

G + cocci
G - cocci
G + bacilli
spirochetes

Question 15

what is the common cause of penicillin G resistance?

Answer 15

mutations in one or more bacterial penicillin binding proteins

Question 16

gonococcal opthalmia in neonates can be prevented by?

Answer 16

silver nitrate drops

Question 17

what is the purpose of procaine in procaine penicillin? which route is it administered via?

Answer 17

procaine acts as an anesthetic by reducing pain at the site of injection.
given by IM route

Question 18

when is benzathine penicillin used? what is its mechanism?

Answer 18

benzathine penicllin is used when prolonged low concentrations of benzyl penicillin are required.
benzylpenicillin dissociates and enters slowly into the bloodstream.

Question 19

what are the indications of benzathine penicllin

Answer 19

rheumatic fever and early or latent syphilis, dosed every 2-4 weeks

Question 20

antistaphylococcal penicillins are stable to penicillinase. True or false
name the antistaphylococcal penicillins

Answer 20

true
methicillin
cloxacillin

Question 21

why is methicillin rarely used? when is it used?

Answer 21

rarely used because of its toxicity

used in MRSA

Question 22

cloxacillin is often prepared in combination with ___________.

Answer 22

amipicillin

Question 23

cloxacillin is unstable to acids but methicillin is stable. True or False?

Answer 23

false. methicillin is unstable and cloxacillin is stable.

Question 24

name the aminopenicillins and their stability status to penicillinase

Answer 24

ampicillin - unstable
amoxacillin - unstable
amoxacillin + clavulanic acid (augmentin) - stable

Question 25

aminopenicllins are unstable to acids. True or false

Answer 25

false. aminopenicllins are stable to acids

Question 26

what is the role of clavulanic acid in augmentin?

Answer 26

its is a beta lactamase inhibitor that protects the drug from enzymatic hydrolysis

Question 27

name a drug that cures listeria meningitis

Answer 27

ampicillin

Question 28

list an example of a drug used to combat sinusitis

Answer 28

ampicillin or amoxacillin

Question 29

name a drug used in the eradication of H.pylori

Answer 29

amoxacillin

Question 30

name two drugs used in dental surgical infections. One of them specifically works against oragnisms with penicillinase activity. identify which one.

Answer 30

amoxacillin used for prophylaxis in dental surgery | amoxacillin and clavulanic acid for severe dental infections (with penicillinase activity)

Question 31

name two drugs used in endocarditis infections

Answer 31

penicillin G and amoxacillin

Question 32

name the main activity that tazobactam imparts along with piparcillin

Answer 32

stability against penicillinase producing micro organisms.

Question 33

piparcillin is not effective against klebsiella. why?

Answer 33

due to constitutive penicillinase activity.

Question 34

antipseudomonal penicillins are unstable against acids. true or false?

Answer 34

true.

Question 35

piparcillin is active against. pseudomonas aeruginosa. true or false

Answer 35

true

Question 36

name the antipseudomonal penicillins

Answer 36

piparcillin | piparcillin + tazobactam

Question 37

name the penicillinase inhibitors. how do they work?

Answer 37

clavulanic acid tazobactam they are beta lactam structures with poor antibiotic activity but affinity to penicillinase enzyme so they block it and protect the drug.

Question 38

penicillin V can be given orally. true or false

Answer 38

true

Question 39

penicillins and aminoglycosides show synergism. why?

Answer 39

penicillins destroy the cell wall allowing aminoglycosides to enter and start inhibition of protein synthesis.

Question 40

penicillins and aminoglycosides should not be placed in the same infusion. why?

Answer 40

penicillin is - charged aminoglycosides are + charged they form an inacitve complex in the same infusion

Question 41

two reasons of natural resistance?

Answer 41

organism lacks cell wall | cell wall impermeable to penicillin

Question 42

three reasons of acquired resistance?

Answer 42

altered permeability altered PBP beta lactamase

Question 43

penicillin G penetrated the CSF when meninges are inflamed only. true or false

Answer 43

true

Question 44

penicillin G is given a. oral b. IV and IM c. oral and IV d. oral and IM

Answer 44

b. IV and IM

Question 45

penicillin G and penicillin V should be administered in the abscence of food. why? name other drugs with the same preference

Answer 45

delayed gastric emptying leads to prolonged contact with acidic environment cloxacillin and augmentin

Question 46

amoxacillin has complete absorption so it is not used in the treatment of?

Answer 46

shigella and salmonella enteritis

Question 47

what is the primary route of excretion of penicillins

Answer 47

tubular secretion and glomerular filteration

Question 48

with penicillins, Impaired renal function requires dose adjustment. normal one hour but with impairment ___ hr.

Answer 48

10 hours

Question 49

what is penicillin combined with if prolonged release is desired? how does it work?

Answer 49

probenecid | inhibits penicillin secretion

Question 50

piparcillin + tazobactam is teratogenic because it crosses the placental barrier. true or false.

Answer 50

false. not teratogenic

Question 51

piparcillin + tazobactam crosses the BBB when meninges are not inflamed. true or false

Answer 51

false. only penetrates CSF when meninges are inflamed and as infection subsides BBB is re established.

Question 52

adverse reactions of penicillins (6 points)

Answer 52

``` hypersensitivity diarrhoea nephrotoxicity neurotoxicity hematologic toxicities cation toxicity ```