Antimicrobials- Purnuske Flashcards Preview

CRRAB II- FINAL > Antimicrobials- Purnuske > Flashcards

Flashcards in Antimicrobials- Purnuske Deck (40):
1

What factors in presentation suggest it is bacterial pharyngitis?

Absence of cough
Age 3-14 years
Anterior cervical lymphadenopathy
Fever
Tonsillar erythema or exudates

2

Is the positive rapid antigen detection test more specific or sensitive?

Specific! (>95%)

Sensitivity = 80%

3

What color are gram + organisms on gram stain?

Purple!

4

What color are gram - organisms on gram stain?

Pink!

5

Describe the difference between treatments:
Prophylactic
Pre-emptive
Empiric
Definitive

Prophylactic: treating when there is risk, but no testing or symptoms

Pre-emptive: actively screening, treat if bug found, still asymptomatic

Empiric: SYMPTOMS! but don't know what organisms is

Definitive: You know what's up

6

What is empiric therapy of choice for community acquired pneumonia in a previously healthy outpatient w/ no prior antibiotic use?

Macrolide (50s) = azithromycin, erythromycin, clarithromycin

Doxycycline (30s)

7

What is empiric therapy of choice for community-acquired pneomnia in a patient with comorbities or previous antibiotic use?

Fluoroquinolone or high dose B-lactam + a macrolide

8

What are the respiratory fluoroquinolones? MOA?

Gemifloxacin
Levofloxacin
Moxifloxacin

MOA = direct inhibitor of DNA replication by binding bacterial DNA topo II and IV

9

Are fluoroquinolones bactericidal or bacteriostatic?

Bactericidial!

10

What is the main mechanism of resistance for floroquinolones?

Mutations in topoisomerase

Active efflux of durg

11

What is the spectrum for floroquinolones?

Gram +
Gram -
Atypical organisms like mycoplasma

12

What would you use to treat mycoplasma pneumonia?

Doxycycline, Azithromycin

13

What is the most likely mechanism for developing a multi-drug resistant infection?

Selection and replication of a colonizing organism that contained a PLASMID encoding SEVERAL resistance determinate genes

14

MOA of Polymyxin E

Binds phosphatidylethanolamine in gram negative membrane to create holes in membrane

15

Major side effect of polymyxin E?

Nephrotoxic!

16

What drugs are used to treat MRSA?

Vancomycin and Linezolid

17

MOA of vancomycin

Binds to D-ala-D-ala dipeptide and inhibits TRANSglycosylation reactions to prevent cell wall synthesis

**binds precursors!

18

MOA of Linezolid

Inhibits protein synthesis by binding to 50S subunit and preventing formation of the initiation complex

19

Why do you administer tazobactam with piperacillin?

Tazobactam is a B-lactamase inhibitor

20

Why do you administer cilastatin with imipenem?

It protects the kidney by inhibiting the enzyme that makes toxic metabolites

21

What is the treatment for a local fungal infection?

Itraconazole
Voriconazole

22

What is the treatment for a systemic fungal infection?

Amphotericin B

23

MOA of Amphotericin B?

Binds ergesterol (unique to fungi)

Forms membrane pores that allow leakage of electrolytes

24

MOA of "azoles"

binds fungal P450 enzyme blocking production of the membrane protein ergosterol and causing the accumulation of Ianosterol

25

What fungal infection is common east of the Mississippi River and Central America and cause an inflammatory lung disease?

Blastomycosis

26

Can blastomycosis be transmitted person-to-person?

Nope!

27

What fungal infection is associated with bird and bat droppings in the mississippi and ohio river valleys?

Histoplasma capsulatum

28

What fungal infection found in the southwestern united states can causes pneumonia and meningitis?

Coccidioidmycosis

29

Where do systemic fungal mycoses disseminate to?

Bones
Joints
CNS

30

If there is CNS involvement during a fungal infection what should you treat with?

Amphotericin B and follow up with itraconazole

31

What are the major adverse side effects of Amphotericin B?

Toxic because binds to cholesterol!

Decreases renal blood flow and can cause permanent BM destruction.

80% patients have nephrotoxicity

32

What fungus primarily infects the lungs and causes a hypersensitivity with brown mucus plugs?

Aspergillus fumigatus causes allergic bronchopulmonary aspergillosis

Can causes systemic disease in immunocompromised

33

What is the main mechanisms of resistance of the azoles?

-Altered cytochrome P450
-Upregulation of efflux pump transporters

34

MOA of B-lactams?

Binds to transpeptidases and block cross-linking of peptidoglycan in cell wall

35

MOA of doxycycline?

Binds to 30S and prevents attachment of aminoacyl-tRNA

36

MOA of Macrolides?

Azithromycin
Clarithromucin
Erythromycin

Binds to 23s rRNA of 50S inhibiting translocation

37

What is the main mechanism of resistance for macrolides?

Methylation of the 23S rRNA binding site prevents binding of drug.

Increased efflux also

38

MOA of fluoroquinolones?

Gemifloxacin
Levofloxacin
Moxifloxacin

*Inhibits Topo II and Topo IV

39

MOA of Oseltamivir, Zanamivir, Peramivir?

Oral prodrug activated by hepatic esterases

inhibits influenza (A & B) neuraminidase thus decreasing release of progeny virus

40

When are the neuraminidase inhibitors most active?

48 hours after infection