Antimicrobials 2 - Smith

Question 1

prokaryotes and Eukaryotes have what type of ribosomes?

Answer 1

prokaryotes = 70 S ribosome
eukaryotes = 80 S ribosome

Question 2

what is the composition of the 70S ribosome vs the 80S ribosome?

Answer 2

70S = 30S + 50S subunits = prokaryotes
80S = 40S + 60S subunits = eukaryotes

Question 3

what drugs that target protein synthesis can target what 3 things?

Answer 3

1. 50S subunit
2. 30S subunit
3. tRNA synthatase

Question 4

what drugs target the 30S ribosomal subunit?

Answer 4

“Buy AT 30”

• Aminoglycosides
• Tetracyclines

Question 5

What are the examples of Tetracycline drugs?

Answer 5

Tetracycline
Doxycycline
Tigecycline
Minocycline

Question 6

what are the examples of Aminoglycosides?

Answer 6

Gentamycin 
Neomycin 
Amikacin 
Tobramycin 
Streptomycin

Question 7

Aminoglycosides are bactericidal or bacteriostatic?

Answer 7

Aminoglycosides = bactericidal

Question 8

Aminoglycosides function how?

Answer 8

Inhibits the 30S Subunit, of aerobic bacteria:

* Blocked initiation, Misreading at translation site, or premature termination

Question 9

Aminoglycosides are clinically used in what?

Answer 9

severe gram negative aerobic bacteria

Question 10

what are the risks of toxicity of Aminoglycosides?

Answer 10

• Nephrotoxicity- decrease dosage in renal function impaired patients
• Ototoxicity - # of destroyed hair cells
• Teratogen
• functional accumulation

Question 11

what is the broadest spectrum aminoglycoside?

Answer 11

amikacin

Question 12

what are the contraindications of tetracyclines?

Answer 12

• don’t give to: children under 8, pregnant women

- don’t take with milk, antacids, or iron tablets

Question 13

how is tetracycline eliminated?

Answer 13

fecally eliminated

Question 14

what is Tigecycline used to treat?

Answer 14

multi-drug resistant Strep pneumoniae, vancomycin resistant enterococci (VRE) and some anaerobes

Question 15

what is the mechanism of tetracyclines?

Answer 15

Inhibits the 30S Subunit, preventing attachment of the aminoacyl-tRNA

Question 16

tetracyclines are bactericidal or bacteriostatic?

Answer 16

bacteriostatic

Question 17

what occurs if someone is allergic to 1 tetracycline, can they have another type of tetracycline?

Answer 17

• if allergic to 1 type they will be allergic to ALL types

Question 18

Tetracyclines are good for treating what?

Answer 18

"VACUUM THe Bed Room"
V- vibrio chlorae
A- acne
C- chlamydia
U- ureaplasma
U- not important 
M- mycoplasma pneumonia
T- Tularemia
H- H. Pylori
B- Borreila burgdorferi (Lymes Disease)
R - Rickettsia

Question 19

location of prokaryotic vs eukaryotic translation?

Answer 19

• prokaryotes: continuous process of both transcription and translation in the cytosol
• eukaryotes: discontinuous process of transcription in the nucleus and translation in the cytoplasm

Question 20

mRNA of prokaryotic vs eukaryotic translation?

Answer 20

• prokaryotes: polycistronic mRNA (1 mRNA can translate into multiple amino acids)
• eukaryotes: monocistronic

Question 21

why can bacteria replicate sooo FAST?

Answer 21

b/c the process of translation is continuous (transcription and translation happen at the same time) and the prokaryotic mRNA is polycistronic

Question 22

what drugs inhibit protein synthesis via tRNA synthetase?

Answer 22

only Mupirocin (Bactroban)

Question 23

what is the mechanism of Mupirocin (Bactroban)

Answer 23

-reversibly inhibits isoleucyl tRNA synthetase

Question 24

is Mupirocin bactericidal or bacteristatic? and against what?

Answer 24

bactericidal against gram positive and some gram negative bacteria

Question 25

what is Mupirocin used to treat?

Answer 25

-topical treatment for MRSA, impetigo and Strep pyogenes

Question 26

what drugs target the 50S ribosomal subunit?

Answer 26

``` "CCEL Quick at 50" C- chlorampenicol C- clindamycin E- erythromycin (macrolides) L- linezolid Q- quinpristin/ dalfopristin (streptogramins) ```

Question 27

what are the Streptogramins?

Answer 27

Quinupristin/dalfopristin

Question 28

what is the mechanism of Streptogramins?

Answer 28

inhibit 50S subunit

Question 29

what are the clinical uses of Streptogramins?

Answer 29

- Life threatening bacteremia w/ VRE - Enterococcus faecium; - Complicated skin infections with S. aureus (VRSA)

Question 30

what are the risks associated with Toxicity of Streptogramins?

Answer 30

Myalgia/ arthralgia

Question 31

how is Streptogramins metabolized?

Answer 31

Streptogramins metabolized by the LIVER

Question 32

Streptogramins are bactericidal or bacteriostatic?

Answer 32

bacteriostatic

Question 33

Linezoid is bactericidal or bacteriostatic?

Answer 33

bacteriostatic

Question 34

what is the mechanism of Linezoid?

Answer 34

Binds 50S subunit and blocks protein synthesis

Question 35

clinically Linezoid is used for what?

Answer 35

- Healthcae associated pneumonia - S. Aureus pneumonia - Infections from MRSA and VRE

Question 36

what are the risks associated with toxicity of Linezoid?

Answer 36

- serotonin syndrome (don't give to patients on SSRI's) | - bone marrow suppression

Question 37

what drugs are considered Macrolines

Answer 37

- Erythromycin - Azithromycin - Clarithromycin

Question 38

what is the mechanism of action of Macrolides?

Answer 38

Inhibits peptide translocation by binding to 50S

Question 39

Macrolides are bactericidal or bacteriostatic?

Answer 39

bacteriostatic

Question 40

what are the clinical uses of Macrolides and what bugs will they treat?

Answer 40

- Upper respiratory infections (sinusitis, otitis media, bronchitis), pneumonia, STD's - gram positive cocci chlamydia, Neisseria, mycoplasma, legionella

Question 41

what are the safest antibiotics and why?

Answer 41

Macrolides are the safest antibiotics because there are low serum levels but the drug concentrates in neutrophils, macrophages and fibroblasts. -can be taken orally

Question 42

how is the mechanism of Azithromycin different from other macrolides and other antibiotics?

Answer 42

it does not inhibit cyt p450 enzymes

Question 43

what is azithromycin effective against?

Answer 43

-respiratory infections due to H. influenza, Moraxella catarrhalis, mycobacterium (not TB)

Question 44

Clindamycin is bactericidal or bacteriostatic?

Answer 44

clindamycin = bacteriostatic

Question 45

what is the mechanism of action for clindamycin?

Answer 45

Blocks peptide bond formation of 50S Subunit

Question 46

Clindamycin is clinically effective in treating what?

Answer 46

"Ann Cline was Always Positive she could C. things were Difficult" - anaerobes - Gram positive cocci (no gram negative activity)

Question 47

what are the risks of toxicity with clindamycin?

Answer 47

overgrowth of Clostridium difficile (pseudomonas colitis)

Question 48

what is the mechanism of action of chloramphenicol?

Answer 48

chloramphenicol - Inhibits 50S peptidyltransferase

Question 49

chloramphenicol is bactericidal or bacteriostatic?

Answer 49

chloramphenicol = bacteriostatic

Question 50

chloramphenicol is clinically effective in treating what?

Answer 50

* **it can cross BBB (meningitis) - meningitis (patients w penicillin allergy) - H. influenza - Rickettsia

Question 51

what is the risk of toxicity with chloramphenicol?

Answer 51

- gray baby syndrome - anemia - teratogenic - inhibits cyt p450 enzyme