Infectious Disease

Question 1

Sensitive staph (MSSA): IV and ORAL Tx

Answer 1

IV: oxacillin/nafcillin or cefazolin (first gen cephalosporin)

Oral: dicloxacillin or cephalexin ( first gen cephalosporin)

Question 2

What microbe most commonly affects Bone, heart, skin and joints.

Answer 2

Staph Aureus

Question 3

Resistant staph (MRSA): Severe infection treatments?

Answer 3

Severe infection: Vancomycin, linezolid, daptomycin, ceftaroline, tigecycline, or telavancin.
Linezolid causes thrombocytopenia.
Daptomycin causes myopathy and a rising CPK.

Question 4

Resistant staph (MRSA): Minor nfection treatments?

Answer 4

Minor infection: Trimethoprim/sulfamethoxazole (TMP/SMX), clindamycin, doxycycline

Question 5

Tx of Staph Aureus in a pt with Penicillin allergy?

Answer 5

– Rash: Safe to use cephalosporins
– Anaphylaxis: Macrolides (azithromycin, clarithromycin) or clindamycin
– Severe infection: Vancomycin, linezolid, daptomycin, telavancin
– Minor infection: Macrolides (azithromycin, clarithromycin), clindamycin,
TMP/SMX

Question 6

Fact! Telavancin is a vancomycin derivative with similar

efficacy.

Answer 6

.

Question 7

Fact! If the organism is sensitive, oxacillin and nafcillin are superior to vancomycin.

Answer 7

.

Question 8

How to treat Strepococcus?

Answer 8

Use the same drugs as Staph.
Medications that are specific for Streptococcus:
·· Penicillin
·· Ampicillin
·· Amoxicillin

Question 9

Gram-negative bacilli (rods)?

Answer 9

Escherichia coli,
Enterobacter,
Citrobacter, 
Morganella, 
Pseudomonas, 
Serratia

Question 10

Treatment for Gram-negative bacilli (rods):

Answer 10

All of the following medications are essentially equal in their efficacy for gram negative bacilli.

1) Cephalosporine
2) Penicillins
3) Monobactam: Aztreoman
4) Quinolones
5) Aminoglycosides
6) Carbapenems

Question 11

Cephalosporine examples?

Answer 11

Cefepime

Ceftazidime

Question 12

Penicillins examples?

Answer 12

Piperacillin

Ticarcillin

Question 13

Quinolones examples?

Answer 13

Ciprofloxacin
Levofloxacin
Moxifloxacin
Gemifloxacin

Question 14

Aminoglycosides examples?

Answer 14

Gentamicin
Tobramycin
Amikacin

Question 15

Carbapenems examples?

Answer 15

Imipenem
Meropenem
Ertapenem
Doripenem

Question 16

Mechanism of Beta-lactam Abx

Answer 16

The 4 beta-lactam antibiotics all inhibit the cell wall by binding the penicillin-binding protein. The 4 classes are:
•• Penicillin
•• Cephalosporins
•• Carbapenem
•• Monobactam (the only one is aztreonam)

Question 17

Treatment of Gastrointestinal anaerobes (Bacteroides)

Answer 17

• • Metronidazole is the best medication for abdominal anaerobes.
• • Carbapenems, piperacillin, and ticarcillin are equal in efficacy for abdominal anaerobes compared to metronidazole.
• • Cefoxitin and cefotetan (in the cephamycin class) are the only cephalosporins that cover anaerobes.

Question 18

Treatment of Respiratory anaerobes (anaerobic strep)

Answer 18

Clindamycin is the best drug for anaerobic strep

Question 19

Medications with no anaerobic coverage

Answer 19

Aminoglycosides, aztreonam, fluoroquinolones, oxacillin/nafcillin, and all the cephalosporins except cefoxitin and cefotetan

Question 20

Tx of herpes simplex, varicella zoster.

Answer 20

Acyclovir, valacyclovir, and famciclovir: All 3 of these agents are equal in efficacy

Question 21

Tx of cytomegalovirus [CMV]

Answer 21

Valganciclovir, ganciclovir, and foscarnet
These are essentially equal in efficacy. They also cover herpes simplex and varicella. Valganciclovir is the best long-term therapy for CMV retinitis.

Question 22

Adverse effect of Valganciclovir and ganciclovir:

Answer 22

Neutropenia and bone marrow suppression

Question 23

Adverse effect of Foscarnet

Answer 23

Renal toxicity

Question 24

oral agents used to tx chronic hepatitis C

Answer 24

Telaprevir, boceprevir, simeprevir, sofosbuvir: None is used as a single agent. Sofosbuvir does not need to be combined with interferon.

Question 25

Influenza A and B tx

Answer 25

Oseltamivir and zanamivir (neuraminidase inhibitors):

Question 26

Hepatitis C (in combination with interferon), respiratory syncytial virus (RSV) treatment

Answer 26

Ribavirin | Ribavirin causes anemia

Question 27

Chronic hepatitis B tx

Answer 27

Lamivudine, interferon, adefovir, tenofovir, entecavir, and telbivudine

Question 28

Mechanisms of Oral Hepatitis C Medications. | 1)Sofosbuvir. 2) Simeprevir, boceprevir, and telaprevir

Answer 28

- Sofosbuvir: RNA polymerase inhibitor - Simeprevir, boceprevir, and telaprevir: Protease inhibitors that prevent viral maturation by inhibiting protein synthesis

Question 29

Fluconazole treats

Answer 29

Candida (not Candida krusei or Candida glabrata), Cryptococcus, oral and vaginal candidiasis as an alternative to topical mediations

Question 30

Itraconazole treats

Answer 30

Largely equal to fluconazole but less easy to use; rarely the best initial therapy for anything

Question 31

Voriconazole treats

Answer 31

Covers all Candida; best agent against Aspergillus. Adverse effect: -- Some visual disturbance

Question 32

Posaconazole treats

Answer 32

Also covers mucormycosis or Mucorales

Question 33

Echinocandins (caspofungin, micafungin, anidulafungin) treats

Answer 33

- - Excellent for neutropenic fever patients. - - Does not cover Cryptococcus. - - Better than amphotericin for neutropenia and fever (less mortality). - - Adverse effect—Echinocandins have no significant human toxicity because they affect/inhibit the 1,3 glucan synthesis step, which does not exist in humans.

Question 34

Mechanism of Antifungal Medications

Answer 34

Azole antifungals inhibit conversion of lanosterol to ergosterol. Ergosterol is the major component of the cell wall of fungi. Disrupting ergosterol damages the cell membrane and increases its permeability, resulting in cell lysis and death.

Question 35

Amphotericin treats

Answer 35

Effective against all Candida, Cryptococcus, and Aspergillus: -- The last 2 main indications for amphotericin are Cryptococcus and mucormycosis.

Question 36

Best meds to treat Aspergillus

Answer 36

Voriconazole superior to amphotericin

Question 37

Best to treat neutropenic fever

Answer 37

Caspofungin superior to amphotericin

Question 38

Fact! Fluconazole vs amphotericin in the tx of candida

Answer 38

Fluconazole is equal to amphotericin to treat candida but has far fewer adverse effects.

Question 39

Adverse effects of amphotericin

Answer 39

renal toxicity (increased creatinine); hypokalemia; metabolic acidosis; fever, shakes, chills

Question 40

Mechanism of Renal Toxicity of Amphotericin

Answer 40

Amphotericin is directly toxic to the tubules. Distal tubule toxicity results in renal tubular acidosis. Distal RTA gives excess potassium and magnesium loss and hydrogen ion retention. When renal toxicity is described, the answer is “Switch to liposomal amphotericin.”