Chapter 34: Bacterial and Mycobacterial Infections: Cell Wall Synthesis

Question 1

Drug of choice for methicillin resistant staph aureus infections? MOA?

Answer 1

Vancomycin

Bind to the D ALa D Ala part of murein monomer…inhibits peptidoglycan glycosyltransferase –> murein monomers can’t add to the growing chain

Question 2

What is a common adverse effect of vancomycin, telavancin, and teicoplanin? How can it be avoided?

Answer 2

Red Man Syndrome: flushing and erythema

Can be avoided by slowing transfusion rate

Question 3

Because of its toxicity, vancomycin is only used when?

Answer 3

Only used when multidrug resistance is present

Question 4

What are the two different uses of Bacitracin?

Answer 4

Cutaneous and eye infections: Topical
Decontaminate c diff: Oral

Most commonly used topically so that systemic absorption does not occur and cause nephrotoxicity

Question 5

Bacitracin MOA?

Answer 5

Inhibits dephosphorylation of bactoprenyl diphosphate by forming a complex with it

BACitracin –> BACtoprenyl

Question 6

Which is more toxic to the liver, vancomycin or telavancin?

Answer 6

telavancin

“tele”vision is toxic

Question 7

MOA of B lactams? How do penicillins differ from cephalosporins?

Answer 7

inhibit transpeptidase by forming covalent acyl enzyme intermediates “dead end”

suicide substrate inhibition

Penicillins are 5 MEMBERED RING; cephalosporins are 6

Question 8

Penicillin G and penicillin V - are they B lactamase sensitive or resistant?

Answer 8

sensitive

Question 9

What would you use to treat aerobic or anaerobic infections of the head/neck? i.e. a dental abscess?

Answer 9

Penicillin V

Question 10

Penicillin can potentiate the effects of what drug?

Answer 10

anticoagulant effects of warfarin

“penicillin & wartime”

Question 11

Which penicillins are used to mainly to treat skin and soft tissue infections?

Answer 11

METHICILLIN
Oxacillin
Cloxacillin
Dicloxacillin
Nafcillin

Question 12

What is the drug of choice for uncomplicated ear, nose, throat infections? Endocarditis prevention? Combo therapy for h. pylori?

What is the stipulation with administration?

Answer 12

Amoxicillin

Because it is B lactamase sensitive, give it with a B lactamase inhibitor (Clavulanic acid)

Question 13

Ampicillin is used in what scenarios?

Answer 13

Listeria meningitis and invasive enterococcal infections

“Get AMPed to write a LIST!!!!!”

also can be used in b lactamase producing bacteria like

1) staph aureus
2) h influenzae
3) e coli
4) klebsiella
5) anaerobes

Question 14

Which penicillins have broad spectrum antibactericidal activity but are used mostly to treat p. aeruginosa?

Answer 14

carbenicillin
ticarcillin
piperacillin
mezlocillin

Question 15

Cycloserine MOA and clinical app?

Answer 15

inhibit alanine racemase and D ala D ala ligase to prevent cell wall synthesis

m tuberculosis
“shake your tuber-cle like a cyclo-ne”

Question 16

What drug would you use to treat gram negative urinary tract infections? MOA?

Answer 16

fosfomycin

PEP analogues - block production of murein monomers

Question 17

Which cephalosporins may produce alcohol intolerance syndrome?

Answer 17

cefotetan

cefoperazone

Question 18

Major clinical application of Ceftriaxone? 3rd gen

Answer 18

Enterobacteriacea (gram neg)

Question 19

Which generation of cephalosporins have the best gram positive coverage?

Answer 19

First generation: cefazolin, cephalexin

Question 20

Cefepime

Answer 20

Cephalosporin 4th generation
Used for p. aeruginosa and enterobacteriae
NOT approved for meningitis

Question 21

Ceftaroline

Answer 21

MRSA
VRSA
= great for multidrug resistant staph aureus

Question 22

What B lactam would you use for a patient allergic to penicillin?

Answer 22

Aztreonam

Question 23

Daptomycin MOA and clinical app?

Answer 23

integrates into gram positive membranes to form pores –> cell death

complicated skin infections
R sided endocarditis from staph aureus

Question 24

What are the major adverse effects and contraindications of daptomycin?

Answer 24

C diff

Don’t use with statins

Question 25

Mainstay of treatment for tuberculosis??

Answer 25

THE BIG FIVE

• ethambutol
• pyrazinamide
• isoniazid
• rifampin
• streptomycin

Combination therapy is a must

Question 26

How many of the big five do you use if the patient has isoniazid resistance?

Answer 26

4

Question 27

Why don’t we use B lactams singularly to treat mycobacterium tuberculosis?

Answer 27

mycobacterium tuberculosis has very high b lactamase activity = highly resistant

Question 28

Which antimycobacterial agent is associated with optic neuritis and requires frequent eye exams?

Answer 28

Ethambutol

E for Eye