Antibiotics

Question 1

Which drug cannot be used for pneumonia and why not?

Answer 1

Daptomycin –inactivated by lung surfactant

Question 2

How should you treat pseudomonas systemic infection and why

Answer 2

Use fluorquinolones in combination, since pseudomonas has efflux pumps

Question 3

All cephalosporins have NO clinically reliable activity against what bacteria?

Answer 3

Enterococci

Question 4

Which antibiotic should never be used alone to treat any infection? Why?

Answer 4

Rifampin due to rapid resistance development

Question 5

Which drug treatment is associated with a life-threatening serotonin syndrome if on antidepressant theory and why?

Answer 5

Linezolid – it is a reversible MAO inhibitor

Question 6

Which antibiotic may cause hypertension if given with tyramine containing foods?

Answer 6

Linezolid

Question 7

What are two important clinical precautions with tetracycline?

Answer 7

-can cause photosensitivity -chelated by divalent cations (bad because can stick to calcium and discolor teeth during development in children)

Question 8

Quinupristin/Dalfopristin has NO activity against this bacteria

Answer 8

Enterococcus faecalis

Question 9

What is an important alarm regarding aminoglycosides?

Answer 9

Use in combination only, since high resistance risk with monotherapy

Question 10

What two drug must be used in combination since there is high resistance development?

Answer 10

1. Rifampin 2. Aminoglycosides

Question 11

Which two antibiotics are associated with prolonged QT intervals?

Answer 11

1. Macrolides 2. FQs

Question 12

Which drug can cause taste perversion/metallic taste?

Answer 12

Metronidazole

Question 13

List the 4 beta lactam cell wall active antibiotics

Answer 13

1. Penicillins 2. Cephalosporins 3. Carbapenems 4. Monobactams

Question 14

What are the 5 classifications of penicillins?

Answer 14

1. Natural PCNs 2. Penicillinase resistance (anti-staph) 3. Aminopenicillins 4. Antipseudomonal 5. PCN-beta lactamase enzyme inhibitor combinations

Question 15

What is the best (only) treatment for syphilis?

Answer 15

Natural penicillin (even if allergic!)

Question 16

What are the two important anti-staph PCNs?

Answer 16

1. Nafcillin 2. oxacillin

Question 17

What is the first modified PCN group to increase reactivity against gram negative bacteria?

Answer 17

Aminopenicillins

Question 18

Most cephalosporins have NO reliable activity against anerobes. Which two drugs are the exception?

Answer 18

Cefotetan, and Cefoxitin (2nd generation)

Question 19

What is the one important monobactam and main function?

Answer 19

Aztraonam -A TREe has fallen through the center of our house, leaving only the square portion (beta-lactam ring) standing, and letting all the air in (aerobic). If this happened to your house it’d be a negative experience -treats gram negative aerobic bacteria, including pseudomonas aeruginosa

-NO activity against gram (+), anaerobes, or atypical

Question 20

What are beta lactamases (penicillinase) and what are their function?

Answer 20

-serine proteases -evolved from penicillin binding protein (transpeptidase) -catalyze the hydrolysis of the antibiotic’s beta-lactam bond -only need a small amount of enzyme to destroy large amount of drug

Question 21

How has Methicillin-Resistant Staph aureus (MRSA) acquired resistance to anti-staph PCNs?

Answer 21

• change in PBP enzyme targets

Question 22

What are the 2 available agents for anti-staphylococcal PCNs (penicillinase-resistance), and what is their main spectrum of activity?

Answer 22

1. cloxacillin / dicloxicillin (po)
2. nafcillin / oxacillin (iv)

SOA:

• Streptococci (Group A, B, C)
• Strep pneumoniae
• MSSA

~Staph epidermidis

Question 23

Aminopenicillins are often combined with beta-lactamase inhibitors. What is the important structural change in beta-lactamase inhibitors compared to penicillins??

Answer 23

• Lacks the 6-acylamino side chain of the penicillins
• allows for a better fit into the active site of the beta-lactamase (penicillinase) and more **persistent binding **

Question 24

Amoxicillin and Ampicillin (aminopenicillins) alone target mostly _____ bacteria. However, when coupled with beta-lactamase inhibitors, what is their increased spectrum of activity?

Answer 24

alone target most gram (+) bacteria (strep, enterococci) and limited gram negative (Neisseria, Haemophilus influenzae, E. coli)

combined:

• improved gram positive (staph)
• broader gram negative
• improved anaerobic

combined =

ampicillin/sulbactam (Unasyn)

amoxacillin/clavulanate (Augmentin)

Question 25

Which penicillin group has broad spectrum empiric therapy use or targeted therapy of hostpial-acquired infections?

Answer 25

Anti-pseduomonal PCNs

Question 26

Most important Anti-psuedomonal PCN

Answer 26

Piperacillin

Question 27

Anti-psuedomonal PCNs spectrum of activity

Answer 27

- more active against **Gram (-)** and less active against Gram (+) - concern for increasing resistance against Pseudomona aeruginosa! - active against **most anaerobes (clostridium)** - **enterics **

Question 28

What makes cephalosporins more stable to penicillinase (beta-lactamase) degradation than penicillin?

Answer 28

-Ceph's ring structure is **less strained** and **more planar** = less reactive = reduced tendency to hydrolyze = more stable

Question 29

4th generation cephalosporin

Answer 29

Cefepime

Question 30

Cephalosporins are (Bactericidal/Bacteriostatic)

Answer 30

Bactericidal

Question 31

Relative cross-allergenicity risk of carbapenems for patients with PCN allergies

Answer 31

only 5-10% risk

Question 32

Most skin-test confirmed cross-reactivity occurs with penicillin allergies and which generation cephalosporin?

Answer 32

1st generation

Question 33

Two narrow spectrum antibiotics

Answer 33

1. penicillin (only aerobic gram positive cocci 2. metronidazole (only aerobes)

Question 34

Nearly 50% of documented PCN-allergic patients have cross-reactivity to \_\_\_\_

Answer 34

imipenem

Question 35

Which antibiotics can cause "Red-man syndrome?"

Answer 35

- related to histamine release - Vancomycin - Dalbavancin

Question 36

Macrolides are (bacteriostatic/bactericidal)

Answer 36

Bacteriostatic

Question 37

List the bacteriostatic drugs (6)

Answer 37

1. Penicillin (static towards enterococci and have no activity against atypical pathogens like chlamydia, legionella, myco) 2. Macrolides (think of the birds just sitting in all the sketchy videos, static, not moving) 3. Tetracycline (its such a baby drug obviously it is) 4. Chloramphenicol 5. Clindamycin 6. Linezolid (against staph and entero! but its cidal against strep!) \*some, like sulfonamides, may be both static and cidal, depending on the organism or drug concentration

Question 38

List two important broad spectrum drugs

Answer 38

1. meropenem (all aerobic and anaerobic gram pos and neg) 2. levofloxacin (majority of aerobic gram pos and neg) 3. glycycyclines

Question 39

You cannot use IV unfractionated heparin for 48 hours after infusion of which drug? Why not?

Answer 39

Oritavancin --interferes with PTT test

Question 40

Which antibiotic is known to cause hypermesis?(nausea, vomiting, hung-over feeling)

Answer 40

Tigecycline

Question 41

Which antibiotic is strongly associated with seizures?

Answer 41

Imipenum

Question 42

Which carbapenem has NO activity against pseudomonas?

Answer 42

Ertapenem (carbapenem)