Antimicrobials Flashcards Preview

Term III: Pharmacology > Antimicrobials > Flashcards

Flashcards in Antimicrobials Deck (55)
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1
Q

Isoniazid (INH)

A

Anti-biotic
Inhibits synthesis of mycolic acid

Prophylaxis for mycobacteirum infections

2
Q

Cotrimoxazole (Bactrim)

A

Anti-biotic

Inhibits folate metabolism

Mixture of sulfonamide and trimethoprim

3
Q

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

A

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

Penicillin: Syphilis
Nafcillin: MSSA

4
Q

What was the first orally available penicillin?

A

AmOxicillin

5
Q

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

A

Peptidoglycans, lipoteichoic acids

6
Q

Gram - bacteria have what in their cell walls?

A

LPS

7
Q

What enzyme do bacteria synthesize to resist penicillin?

A

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

8
Q

How does penicillin work?

A

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

9
Q

Augmentin

A

Antibiotic - inhibits penicillinase

Amoxicillin + clavulanic acid

10
Q

Zosyn

A

Antibiotic
Piperacillin + tazobactam (inhibits pencillinase)

Intensive care setting and covers both Gram + and - organisms

11
Q

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

A

Gram +

12
Q

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

A

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

13
Q

Gram (-) Bacteria - PEKHEN

A

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

14
Q

Gram (+) Bacteria - CLEPSS

A

Clostridium, Listeria, Enterococcus, Pneumococcus, Staph, Strep

15
Q

Vancomycin

A

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

MRSA

16
Q

**floxacins/Fluoroquinolones - Cipro/Ciprofloxacin and Moxifloxacin

A

Antibiotic - inhibit DNA gyrase

Community-acquired pneumonia

17
Q

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

A

Less Gram +, more Gram -

18
Q

Rifampin/Rifamycin

A

Inhibits bacterial RNA polymerase; also mitochondrial RNA polymerase

TB

19
Q

**cycline - Tetracycline

A

Antibiotic - inhibit protein synthesis

20
Q

Bacteriostatic vs. bactericidal

A

Stop bacterial growth vs. kill bacteria

21
Q

Narrow spectrum vs. broad spectrum

A

Narrow spectrum - covers one or a couple bugs

Broad spectrum - covers lots of bugs

22
Q

What antibiotic can cause anaphylactic rxn due to allergies?

A

Penicillin

23
Q

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

A

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

24
Q

Where do aerobic bacteria tend to live in the body?

A

Airway, lungs (oxygen-rich)

25
Q

Where do anaerobic bacteria tend to live in the body?

A

GI tract, GU tract (oxygen-poor)

26
Q
What is the drug of choice to treat syphilis?
A. Cephalosporins
B. Penicillin G
C. Ciprofloxacin
D. Bactrim
E. Azithromycin
A

B

27
Q

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

A

Nosocomial (hospital-acquired) infection

28
Q

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
A

All of the above

29
Q

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

A

Strep pneumoniae or Staph aureus (MSSA)

Treat: Cephalosporins (3rd gen) + Azithromycin OR Moxifloxacin

30
Q

What is synergy? Give example.

A

When certain combinations of antibiotics work better than the drugs alone.

Ex: Penicillins + Aminoglycosides (**mycins) - inhibit both cell wall synthesis and protein synthesis

31
Q

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

A

Prevent opportunistic infections - especially in elderly or immunocompromised

32
Q

Why do bacteria synthesize coagulase?

A

converts fibrinogen –> fibrin, coats bacteria, prevents phagocytosis

33
Q

Why do bacteria synthesize catalase?

A

converts toxic H2O2 –> H20, bacteria can multiply happily

34
Q

Why do bacteria perform hemolysis?

A

Lyses blood & immune cells – more difficult to clear infection

35
Q

Why do bacteria synthesize collagenase, hyaluronidase?

A

spread by digesting extracellular matrix

36
Q

Why do bacteria synthesize toxins?

A

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

37
Q

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

A
  • PPI - to raise pH and decrease acid secretion
  • Antibiotics - to kill H pylori
  • Bismuth - to coat and heal GI surface
38
Q

Why does one have to stop taking aspirin before surgeries?

A

It’s a blood thinner

39
Q

What are two drug-resistant infections?

A

MRSA - methicillin-resistant Staph aureus

VRE - Vancomycin-resistant enterococci

40
Q

Quinupristin / Dalphopristin

A

Anti-biotics

Last resort treatment for VRE

41
Q

Linezolid

A

Inhibits formation of ribosomes

Last resort treatment for Gram + bacteria,

VRE

42
Q

**azole - Ketoconazole

A

Inhibitors of ergosterol synthesis

Anti-fungal

43
Q

Amphotercin

A

Binds ergosterol so cell membrane leaks ions

Anti-fungal

44
Q

Caspofungin

A

Inhibits glucan synthesis

Anti-fungal

45
Q

What are three targets for anti-fungals?

A
  1. Ergosterol
  2. Glucan
  3. Chitin
46
Q

What protozoa causes amebiasis (amoebic dysentery)

A

Entamoeba histolytica

47
Q

What protozoa causes diarrhea and fever?

A

Giardia lamblia

48
Q

Metronidazole (Flagyl)

A

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

49
Q

What parasite causes malaria? How is it propagated?

A

Plasmodium

Mosquito bites –> blood

50
Q

Chloroquine

A

Binds heme

Anti-parasitic, malaria

51
Q

Mebendazole

A

Inhibits microtubule formation and paralyzes worms

Anti-parasitic, helminthic worms

52
Q

Does Mebendazole enter systemic circulation?

A

No - low toxicity

53
Q

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

A

Antibiotic - inhibits proteins synthesis

Clindamycin/Erythromycin - inhibit translocation

Azithromycin - community-acquired pneumonia, broad spectrum antibotic

54
Q

Meropenem

A

Anti-biotic

Last resort treatment for Gram - bacteria

55
Q

Artemisinin

A

Anti-parasitic

Drug resistant strains of malaria