(7) Antimicrobials: Cell Wall & Mem... (1.1-1.7)

Question 1

Other than the cocci, name 3 gram (+) organisms which can be treated with Penicillin

Answer 1

(1) Actinomyces israelii
(2) Clostridium perfringens
(3) Pasteurella multocida
* (Inhibits peptidoglycan synthesis ∴ it’s particularly effective against organisms with thick peptidoglycan cell walls… such as gram (+) organisms)*

Question 2

ROA: Penicillin V

Answer 2

Oral

Question 3

ROA: Penicillin G

Answer 3

IV

Question 4

Name 4 Streptococcal-related indications for Penicillin

Answer 4

(1) Strep pharyngitis
(2) Rheumatic fever
(3) Endocarditis due to S. bovis/S. viridans
(4) S. agalactiae prophylaxis

Question 5

Name 2 gram (-) organisms which can be treated with Penicillin

Answer 5

(1) Treponema pallidum
(2) Neisseria meningitis
* (Note: Penicillin can only treat meningitis due Neisseria meningitidis, as the inflammation opens the pores in the BBB, allowing the drug to enter the CNS)*

Question 6

Resistance: Penicillin

Answer 6

β-lactamases

Question 7

Where in a bacteria are β-lactamase genes found?

Answer 7

Plasmids

Question 8

Adverse Effects (3) : Penicillin

Answer 8

(1) Type I hypersensitivity ⇒ Anaphylaxis
(2) IgG hemolytic anemia
(3) Drug-induced interstitial nephritis
* (Interstitial nephritis is mediated by mononuclear cells)*

Question 9

MOA: Penicillin

Answer 9

Inhibits PBP

(Leads to osmotic cellular lysis)

Question 10

Name 2 alternatives to Methicillin

Answer 10

(1) Nafcillin
(2) Oxacillin
* (And Dicloxacillin, etc.)*

Question 10

What is Methicillin’s spectrum of activity

Answer 10

Staphylococci

Question 10

What type of infections are Methicillin derivatives used to treat?

Answer 10

(1) Soft-tissue infections
(2) Endocarditis
(3) Osteomyelitis

Question 10

What is the mechanism of resistance of MRSA?

Answer 10

Altered PBPs

Question 10

How was Penicillin modified to yield Methicillin?

Answer 10

Addition of bulky R-group

Question 11

Which aminopenicillin has good oral bioavailability?

Answer 11

Amoxicillin

Question 12

Which penicillin is used as part of triple therapy for H. pylori infections?

Answer 12

Amoxicillin

Question 13

What infections is Amoxicillin used to treat?

Answer 13

(1) Streptococcal pharyngitis
(2) Otitis media & Sinusitis
(3) Pneumonia
(4) Early lyme disease

Question 14

What is the gram (-) coverage of the aminopenicillins?

Answer 14

(1) Haemophilus influenzae
(2) GI/Urinary Gram (-) Rods

Question 15

ROA: Ampicillin

Answer 15

IV

Question 16

Name 3 infections Ampicillin is used to treat

Answer 16

(1) Anaerobic infections
(2) Enterococcus
(3) Meningitis due to Listeria

Question 17

Which β-lactamase inhibitor is Amoxicillin usually paired with?

Answer 17

Clavulanate

Question 18

Which β-lactamase inhibitors are paired with Ampicillin?

Answer 18

(1) Tazobactam
(2) Sulbactam

Question 19

What antibiotic is used as prophylaxis against encapsulated bacteria in asplenic patients?

Answer 19

Amoxicillin

Question 20

What antibiotic is used as prophylaxis before dental procedures in patients at risk of endocarditis?

Answer 20

Amoxicillin

Question 21

**Adverse Effects** (2) : Aminopenicillins

Answer 21

(1) Steven-Johnson syndrome (2) Drug-induced liver injury * (And the usual side effects of all penicillins)*

Question 22

Which aminopenicillins are active against Pseudomonas?

Answer 22

(1) Piperacillin (2) Ticarcillin

Question 23

Name 2 first-generation cephalosporins

Answer 23

(1) Cefazolin (2) Cephalexin

Question 24

What is the spectrum of activity of first-generation cephalosporins?

Answer 24

(1) Gram (+) cocci (2) Proteus (3) E. coli (4) Klebsiella

Question 25

What is the drug of choice for surgical prophylaxis?

Answer 25

Cefazolin *(Neomycin to sterilize bowel)*

Question 26

Name 3 second-generation cephalosporins

Answer 26

(1) Cefuroxime (2) Cefotetan (3) Cefoxitin

Question 27

What is the difference in the spectrum of activity of first and second-generation cephalosporins?

Answer 27

Second generation has additional coverage of: (1) H. influenzae (2) Neisseria (3) Serratia

Question 28

Name 3 third-generation cephalosporins

Answer 28

(1) Ceftriaxone (2) Cefotaxime (3) Ceftazidime

Question 29

What antibiotic is used for empiric treatment of meningitis?

Answer 29

Ceftriaxone

Question 30

What are third-generation cephalosporins used to treat?

Answer 30

(1) Meningitis (2) Community & Hospital-acquired pneumonia (3) Pseudomonas infection (4) Endocarditis (5) Gram (-) GI bugs (6) Gonorrhea (7) Lyme disease (late-stage) * (Only Ceftazidime can treat pseudomonas)*

Question 31

Which third-generation cephalosporin can be used to treat Pseudomonas?

Answer 31

Ceftazidime *("CefTAZZZZ covers PseudomonAZZZZZ")*

Question 32

Other than Ceftazidime, what cephalosporin can be used to treat Pseudomonas?

Answer 32

Cefepime

Question 33

Which Cephalosporins are considered broad-spectrum?

Answer 33

(1) Cefepime (2) Ceftaroline

Question 34

Which Cephalosporin is active against MRSA?

Answer 34

Ceftaroline

Question 35

Which generations of cephalosporins are resistant to β-lactamase inhibitors?

Answer 35

(1) 3^rd generation (4) 4^th generation

Question 36

What is the spectrum of activity of monobactams?

Answer 36

Aerobic gram (-) rods *(DOC for Enterobacter)*

Question 37

Name a β-lactam that can treat Pseudomonas which is NOT a Cephalosporin or Penicillin

Answer 37

Aztreonam

Question 38

What drug should be used in patients with meningitis and a penicillin allergy?

Answer 38

Aztreonam

Question 39

Are monobactams sensitive to β-lactamases?

Answer 39

No

Question 40

Are Carbapenems broad spectrum?

Answer 40

Yes

Question 41

What antibiotic should you use when infection is resistant to multiple other treatments?

Answer 41

Carbapenems

Question 42

What enzyme degrades Imipenem?

Answer 42

Dehydropeptidase

Question 43

What antibiotic is coadministered with Cilastin?

Answer 43

Imipenem *("Keep it lastin with cilastin!")*

Question 44

**Adverse Effects** (2) : Carbapenems

Answer 44

(1) GI distress (2) Skin rash

Question 45

Name an antibiotic which lowers the seizure threshold

Answer 45

Imipenem

Question 46

Which drug class is indicated against organisms which synthesize _extended-spectrum_ β-lactamase inhibitors?

Answer 46

Monobactams

Question 47

What is the spectrum of activity of Vancomycin?

Answer 47

Gram (+) Cocci

Question 48

What is the first-line treatment for MRSA?

Answer 48

Vancomycin

Question 49

**MOA**: Vancomycin

Answer 49

Binds D-ala-D-ala ⇒ Inhibits cell wall synthesis *(Unlike penicillins which bind PBP)*

Question 50

Are β-lactamases effective against Vancomycin?

Answer 50

No

Question 51

**ROA**: Vancomycin

Answer 51

IV *(Exception: C. difficile)*

Question 52

What's the empiric treatment for endocarditis?

Answer 52

Vancomycin

Question 53

**Resistance**: Vancomycin

Answer 53

Altered peptidoglycan structure ⇒ D-ala-**D-lac** (Or D-ala-**D-ser**)

Question 54

When is Vancomycin administered orally?

Answer 54

Treatment of C. difficile

Question 55

**Adverse Effects** (5) : Vancomycin

Answer 55

(1) Redman syndrome (2) Thrombophlebitis (3) Ototoxicity (4) Nephrotoxicity (5) DRESS syndrome

Question 56

**Adverse Effect**: Daptomycin

Answer 56

Myopathy

Question 57

What is the spectrum of activity of Daptomycin?

Answer 57

Gram (+)

Question 58

**MOA**: Daptomycin

Answer 58

Depolarizes cell membrane via insertion of lipid tail

Question 59

Is Daptomycin effective against VRSA?

Answer 59

Yes

Question 60

What type of MRSA infection can Daptomycin NOT treat?

Answer 60

Pneumonia *(It's inactivated by surfactant)*