Bacterial cell wall synthesis inhibitors

Question 1

Name 2 classes of bacterial cell wall synthesis inhibitors.

Answer 1

Beta lactams, Glycopeptide

Question 2

Beta lactams bind to the active side of which enzyme?

Answer 2

Transpeptidase (penicillin binding protein)

Question 3

Name 4 types of beta lactams

Answer 3

Penicillins, cephalosporins, carbapenems, monobactam

Question 4

Name the 4 classes of penicillins

Answer 4

1. natural penicillins (Pen G and Pen V),
2. penicillinase resistant penicillins (cloxacillin, flucloxacillin),
3. aminopenicillins (amoxicillin, ampicillin),
4. antipseudomonal penicillins (piperacillin)

Question 5

Which natural penicillin is administered parenterally?

Answer 5

Penicillin G

Question 6

Syphilis caused by Treponema pallidum can be treated with which penicillin?

Answer 6

Penicillin G

Question 7

Are natural penicillins commonly used against Staphylococcus aureus?

Answer 7

No

Question 8

Which class of penicillin is commonly used against methicillin sensitive Staphylococcus aureus?

Answer 8

Penicillinase resistant penicillins

Question 9

How does methicillin sensitive Staphylococcus aureus acquire resistance against the natural penicillins?

Answer 9

They produce penicillinases

Question 10

Which bacteria is cloxacillin effective against?

Answer 10

Methicillin Sensitive Staphylococcus aureus (MSSA)

Question 11

How are the penicillins mainly cleared?

Answer 11

Renal clearance

Question 12

Name the 2 aminopenicillins

Answer 12

Ampicillin, amoxicillin

Question 13

Are aminopenicillins effective against beta lactamase producing strains of bacteria?

Answer 13

No

Question 14

Which of the aminopenicillins (amoxicillin or ampicillin) has better oral absorption?

Answer 14

Amoxicillin

Question 15

Does aminopenicillins sufficiently cover Pseudomonas and Klebsiella?

Answer 15

No

Question 16

How are aminopenicillins cleared?

Answer 16

Renal excretion

Question 17

How is piperacillin administered?

Answer 17

Intravenously

Question 18

Which class of penicillins has coverage against Pseudomonas, Proteus and Klebsiella?

Answer 18

Anti-pseudomonal penicillins (piperacillin)

Question 19

Name 3 beta lactams-beta-lactamase inhibitor combination drugs.

Answer 19

1. Augmentin (Amoxicillin + clavulanic acid)
2. Unasyn (ampicillin + sulbactam)
3. Zosyn (piperacillin + tazobactam)

Question 20

How do beta-lactamase inhibitors work?

Answer 20

They either covalently bind at or near the active site of the β-lactamase and restructures it, permanently inactivating. In doing so, they protects other beta-lactam antibiotics from beta-lactamase catalysis.

Question 21

Name a microbe that commonly causes nosocomial infections and is resistant to all penicillins.

Answer 21

MRSA (methicillin resistant Staphylococcus aureus)

Question 22

Name at least 2 penicillins related life-threatening allergic reactions.

Answer 22

1. Anaphylaxis
2. Stevens Johnson syndrome
3. Toxic epidermal necrolysis

Question 23

Which generation of cephalosporins does cefazolin and cephalexin belong to?

Answer 23

First generation

Question 24

Which generation of cephalosporins are primarily administered orally?

Answer 24

First and second generation cehalosporins. Cefazolin (first generation) is an exception.

Question 25

How are the 3rd, 4th and 5th generation cephalosporins administered?

Answer 25

Parenterally

Question 26

Name at least 3 types of microbes against which first and second generation cephalosporins are ineffective?

Answer 26

1. *Pseudomonas aeruginosa* and (LAME species) 1. **L**isteria monocytogenes, 2. **A**typicals (Mycoplasma, Chlamydia, Legionella spp.), 3. **M**RSA, and 4. **E**nterococcus species

Question 27

Ceftriaxone belongs to which generation of cephalosporins?

Answer 27

Third generation

Question 28

Name one cephalosporin from the third and fourth generation each which is effective against *Pseudomonas aeruginosa.*

Answer 28

Third generation – Ceftazidime Fourth generation - Cefepime

Question 29

Which generation of cephalosporins has coverage against MRSA?

Answer 29

Fifth generation (ceftobiprole, ceftaroline)

Question 30

How are most cephalosporins cleared?

Answer 30

Renal clearance

Question 31

How is ceftriaxone cleared?

Answer 31

Hepatic clearance

Question 32

Explain the mechanism of resistance underlying MRSA.

Answer 32

MRSA expresses an altered penicillin binding protein (PBP2a) with reduced affinity for the penicillins

Question 33

Name 3 advantages the third generation and fourth generation cephalosporins have over the first and second generations.

Answer 33

1. Higher activity against Gram-negative bacteria 2. Greater resistance against the beta-lactamase producing strains 3. Greater CSF penetration

Question 34

Does cephalosporin have cross reactivity with penicillins?

Answer 34

Yes

Question 35

Does cephalosporin have cross reactivity with penicillins?

Answer 35

Yes

Question 36

Name the class of antibiotics that are commonly used against extended spectrum beta-lactamase (ESBL) producing bacteria?

Answer 36

Carbapenems

Question 37

Name 3 carbapenems.

Answer 37

1. Imipenem, 2. meropenem, 3. ertapenem

Question 38

How are carbapenems administered?

Answer 38

Parenterally

Question 39

Imipenem is combined with \_\_\_\_\_\_\_\_\_\_, which works by \_\_\_\_\_\_\_\_\_\_.

Answer 39

cilastatin, inhibiting dehydropeptidase 1 (DHP1) found in the brush border of the proximal renal tubule. (DHP1 is necessary for the hydrolysis of imipenem. It is not a beta lactamase inhibitor.)

Question 40

Can carbapenems be used to treat MRSA?

Answer 40

No

Question 41

Which carbapenem has good CSF penetration?

Answer 41

Meropenem

Question 42

Which of the following carbapenems is not effective against *Pseudomonas aeruginosa*?

Answer 42

Ertapenem

Question 43

Which drug classes of beta lactams have cross reactivity with penicillins?

Answer 43

Cephalosporins, carbapenem

Question 44

Which drug class does aztreonam belong to?

Answer 44

Monobactam

Question 45

Aztreonam is effective against Gram-

Answer 45

negative bacteria (no activity against Gram positive and anaerobic microbes)

Question 46

Does aztreonam have cross-sensitivity to penicillin?

Answer 46

No

Question 47

What are some adverse effects related to the use of penicillins, cephalosporins and carbapenems?

Answer 47

GIT related symptoms (vomiting diarrhea), hypersensitivity (Symptoms range in severity, from a minor rash to life-threatening conditions like anaphylaxis)

Question 48

Vancomycin is useful against Gram \_\_\_\_\_\_\_\_\_\_\_

Answer 48

positives

Question 49

How is vancomycin commonly administered?

Answer 49

Intravenously

Question 50

When is oral vancomycin preferred?

Answer 50

Clostridium difficile-associated diarrhea (CDAD) or the more severe antibiotic-associated pseudo-membranous colitis.

Question 51

What is the first line of antibiotics for CDAD?

Answer 51

Vancomycin

Question 52

Vancomycin interferes with cell wall synthesis by inhibiting \_\_\_\_\_\_\_\_\_\_\_

Answer 52

transglycosylation

Question 53

Name 3 antibiotics that work by inhibiting bacterial cell wall synthesis, and are effective against MRSA?

Answer 53

1. ceftobiprole (Fifth generation cephalosporins) 2. ceftaroline (Fifth generation cephalosporins) 3. Vancomycin

Question 54

How is vancomycin cleared?

Answer 54

Renal clearance

Question 55

Name 3 adverse effects related to vancomycin

Answer 55

1. Nephrotoxicity, 2. Ototoxicity, 3. Red man syndrome