Antimicrobials

Question 1

Isoniazid (INH)

Answer 1

Anti-biotic
Inhibits synthesis of mycolic acid

Prophylaxis for mycobacteirum infections

Question 2

Cotrimoxazole (Bactrim)

Answer 2

Anti-biotic

Inhibits folate metabolism

Mixture of sulfonamide and trimethoprim

Question 3

***cillins - Penicillin, Methicillin, Amoxicillin, Nafcillin

Answer 3

Inhibit cell wall synthesis by covalently/irreversibly binding and inactivating transpeptidases (act as suicide substrates)

Penicillin: Syphilis
Nafcillin: MSSA

Question 4

What was the first orally available penicillin?

Answer 4

AmOxicillin

Question 5

Gram + bacteria have what 2 things in their cell walls?

Answer 5

Peptidoglycans, lipoteichoic acids

Question 6

Gram - bacteria have what in their cell walls?

Answer 6

LPS

Question 7

What enzyme do bacteria synthesize to resist penicillin?

Answer 7

Penicillinase aka beta-lactamase (opens the beta-lactam ring in penicillin)

Question 8

How does penicillin work?

Answer 8

Covalently/irreversibly binds transpeptidases (rqd for cell wall sythesis) and inactivates them

Question 9

Augmentin

Answer 9

Antibiotic - inhibits penicillinase

Amoxicillin + clavulanic acid

Question 10

Zosyn

Answer 10

Antibiotic
Piperacillin + tazobactam (inhibits pencillinase)

Intensive care setting and covers both Gram + and - organisms

Question 11

Are penicillins more effective against Gram + or Gram - bacteria?

Answer 11

Gram +

Question 12

Cephalosporins (Cef***) - Cefazolin, Cefoxitin, Ceftriaxone, Cefepime

Answer 12

Anti-biotic - inhibits cell wall synthesis by irreversibly binding to transpeptidases

More resistant to beta-lactamases, has less hypersensitivity rxns, and more Gram (-) coverage

1st gen: MSSA, PEK
2nd gen: MSSA, HENPECK
3rd gen: community-acquired pneumonia, meningitis

Question 13

Gram (-) Bacteria - PEKHEN

Answer 13

Proteus, E coli, Klebsiella, Haemophilus, Enterobacter, Neisseria

Question 14

Gram (+) Bacteria - CLEPSS

Answer 14

Clostridium, Listeria, Enterococcus, Pneumococcus, Staph, Strep

Question 15

Vancomycin

Answer 15

Anti-biotic
Inhibits cell wall synthesis - binds D-alanine and prevents transpeptidase enzyme for cross-linking

MRSA

Question 16

**floxacins/Fluoroquinolones - Cipro/Ciprofloxacin and Moxifloxacin

Answer 16

Antibiotic - inhibit DNA gyrase

Community-acquired pneumonia

Question 17

Newer generation drugs have less _____ coverage and more ____ coverage.

Answer 17

Less Gram +, more Gram -

Question 18

Rifampin/Rifamycin

Answer 18

Inhibits bacterial RNA polymerase; also mitochondrial RNA polymerase

TB

Question 19

**cycline - Tetracycline

Answer 19

Antibiotic - inhibit protein synthesis

Question 20

Bacteriostatic vs. bactericidal

Answer 20

Stop bacterial growth vs. kill bacteria

Question 21

Narrow spectrum vs. broad spectrum

Answer 21

Narrow spectrum - covers one or a couple bugs

Broad spectrum - covers lots of bugs

Question 22

What antibiotic can cause anaphylactic rxn due to allergies?

Answer 22

Penicillin

Question 23

What cocktail is used for post-exposure prophylaxis for HIV?

Answer 23

2+1 HAART (same one used for treatment of HIV patients)

Question 24

Where do aerobic bacteria tend to live in the body?

Answer 24

Airway, lungs (oxygen-rich)

Question 25

Where do anaerobic bacteria tend to live in the body?

Answer 25

GI tract, GU tract (oxygen-poor)

Question 26

``` What is the drug of choice to treat syphilis? A. Cephalosporins B. Penicillin G C. Ciprofloxacin D. Bactrim E. Azithromycin ```

Answer 26

B

Question 27

What type of infection is more likely to be drug resistant? Community-acquired or nosocomial?

Answer 27

Nosocomial (hospital-acquired) infection

Question 28

How do bacteria become resistant to drugs? 1. Degrade the drug (penicillinase) 2. Change/mutate targets - altered penicillin binding proteins 3. Up-regulate efflux pumps 4. Alter membrane/decrease permeability 5. Transfer resistance genes from other cells (plasmids) 6. All of the above

Answer 28

All of the above

Question 29

What organisms are most likely responsible for community acquired pneumonia? What is the treatment?

Answer 29

Strep pneumoniae or Staph aureus (MSSA) Treat: Cephalosporins (3rd gen) + Azithromycin OR Moxifloxacin

Question 30

What is synergy? Give example.

Answer 30

When certain combinations of antibiotics work better than the drugs alone. Ex: Penicillins + Aminoglycosides (****mycins) - inhibit both cell wall synthesis and protein synthesis

Question 31

What would be a reason for prescribing antibiotics to someone with a viral infection?

Answer 31

Prevent opportunistic infections - especially in elderly or immunocompromised

Question 32

Why do bacteria synthesize coagulase?

Answer 32

converts fibrinogen --> fibrin, coats bacteria, prevents phagocytosis

Question 33

Why do bacteria synthesize catalase?

Answer 33

converts toxic H2O2 --> H20, bacteria can multiply happily

Question 34

Why do bacteria perform hemolysis?

Answer 34

Lyses blood & immune cells – more difficult to clear infection

Question 35

Why do bacteria synthesize collagenase, hyaluronidase?

Answer 35

spread by digesting extracellular matrix

Question 36

Why do bacteria synthesize toxins?

Answer 36

to get more nutrients, water, electrolytes, etc. from host cells

Question 37

What types of drugs should you use to treat an ulcer?

Answer 37

- PPI - to raise pH and decrease acid secretion - Antibiotics - to kill H pylori - Bismuth - to coat and heal GI surface

Question 38

Why does one have to stop taking aspirin before surgeries?

Answer 38

It's a blood thinner

Question 39

What are two drug-resistant infections?

Answer 39

MRSA - methicillin-resistant Staph aureus VRE - Vancomycin-resistant enterococci

Question 40

Quinupristin / Dalphopristin

Answer 40

Anti-biotics | Last resort treatment for VRE

Question 41

Linezolid

Answer 41

Inhibits formation of ribosomes Last resort treatment for Gram + bacteria, VRE

Question 42

****azole - Ketoconazole

Answer 42

Inhibitors of ergosterol synthesis Anti-fungal

Question 43

Amphotercin

Answer 43

Binds ergosterol so cell membrane leaks ions Anti-fungal

Question 44

Caspofungin

Answer 44

Inhibits glucan synthesis Anti-fungal

Question 45

What are three targets for anti-fungals?

Answer 45

1. Ergosterol 2. Glucan 3. Chitin

Question 46

What protozoa causes amebiasis (amoebic dysentery)

Answer 46

Entamoeba histolytica

Question 47

What protozoa causes diarrhea and fever?

Answer 47

Giardia lamblia

Question 48

Metronidazole (Flagyl)

Answer 48

Binds electron transport proteins, resulting in cell death Only kills dividing cells, not cysts Anti-protozoan, anti-biotic, anti-parasitic Infections of GI, vagina, urethra DO NOT TAKE WITH ALCOHOL --> vomiting

Question 49

What parasite causes malaria? How is it propagated?

Answer 49

Plasmodium Mosquito bites --> blood

Question 50

Chloroquine

Answer 50

Binds heme Anti-parasitic, malaria

Question 51

Mebendazole

Answer 51

Inhibits microtubule formation and paralyzes worms Anti-parasitic, helminthic worms

Question 52

Does Mebendazole enter systemic circulation?

Answer 52

No - low toxicity

Question 53

****mycin - Streptomycin, Azithromycin (Z-pack), Clindamycin, Erythromycin

Answer 53

Antibiotic - inhibits proteins synthesis Clindamycin/Erythromycin - inhibit translocation Azithromycin - community-acquired pneumonia, broad spectrum antibotic

Question 54

Meropenem

Answer 54

Anti-biotic | Last resort treatment for Gram - bacteria

Question 55

Artemisinin

Answer 55

Anti-parasitic Drug resistant strains of malaria