Infectious Disease

Question 1

MRSA Drugs

Answer 1

Telavancin
Dalbavancin
Tedizolid
Oritavancin
Vancomycin
Daptomycin
Linezolid
Ceftaroline

Question 2

MSSA Drugs

Answer 2

FIRST LINE
IV: oxacillin, nafcillin, cefazolin
PO: dicloxacillin, cephalexin, cefadroxil

SECOND LINE
IV: any cephalosporin, any carbapenem, beta-lactam/beta-lactamase
PO: amoxicillin/clavulanate, oral cephalosporins

Question 3

First line MRSA Drugs

Answer 3

IV: vancomycin. linezolid, daptomycin, cetaroline
PO: linezolid, TMP/SMX, doxycycline

Question 4

What is the best empiric therapy for gram-positive cocci in blood cultures?

Answer 4

Vancomycin

Question 5

Adverse effects of linezolid

Answer 5

thrombocytopenia

interaction with MAOIs

Question 6

Adverse effects of Daptomycin

Answer 6

CPK (creatine kinase) elevation

Not effective for lung infections

Question 7

What medications are used to treat minor MRSA infections of the skin?

Answer 7

TMP/SMX
Doxycycline
Clindamycin
Linezolid

Question 8

What bacteria are covered by amoxicillin?

Answer 8

HELPS

H. influenzae
E. coli
Listeria
Proteus
Salmonella

Question 9

Amoxicillin is the best initial therapy for what?

Answer 9

Otitis media
Dental infection
Endocarditis prophylaxis
Lyme disease that is limited to rash, joint, or CN VII
UTI in pregnant women
Listeria
Enterococcal infections

Question 10

What are the penicillinase-resistant penicillins (PRPs)? What are they used to treat?

Answer 10

Oxacillin
Cloxacillin
Dicloxacillin
Nafcillin

Used to treat:
Skin infections (cellulitis, impetigo, erysipelas)
Endocarditis, meningitis, staph bacteremia
Osteomyelitis and septic arthritis when organism is sensitive

Not effective against MRSA or Enterococcus

Question 11

Why is methicillin never the right answer?

Answer 11

It causes renal failure secondary to allergic interstitial nephritis.

Question 12

What bacteria are covered by piperacillin, ticarcillin, azlocillin, mezlocillin? They are the best initial therapy for what?

Answer 12

Gram negative bacilli (E. coli and Proteus) from the Enterobacteriaceae group and Pseudomonas

Best initial therapy for:
Cholecystitis
Pyelonephritis
Bacteremia
Hospital acquired pneumonia
Neutropenia and fever

Question 13

What is the only cephalosporin that covers MRSA? What generation is it?

Answer 13

Ceftaroline

5th generation

Question 14

Babesiosis

Answer 14

Babesia microti
Ixodes tick
Flu-like symptoms, ARDS, splenic rupture, DIC, CHF
Anemia, thrombocytopenia, intravascular hemolysis (jaundice, dark urine)
Elevated bilrubin, LFTs, and LDH
Diagnosis: thin blood smear showing intraerythrocytic rings – Maltese Crosses
Treatment: Atovaquone + Azithromycin, Quinine + Clindamycin if severe

Note: higher risk if immunocompromised, >50 years old, or with history of splenectomy

Question 15

What illnesses are carried by the Ixodes tick?

Answer 15

Babesiosis, Lyme, and Human Granulocytic Anaplasmosis

Question 16

How do you diagnose Babesiosis? What are the findings?

Answer 16

Thin blood smear

Intra-erythrocytic rings – Maltese Cross

Question 17

What is the treatment for Babesiosis?

Answer 17

Atovaquone + Azithromycin

Quinine + Clindamycin for severe cases

Question 18

Erysipelas

Answer 18

Strep pyogenes (Group A Strep)
Superficial dermal and lymphatics with raised and sharply demarcated edges, commonly affects the outer ear
Rapid onset and spread
Fever early in course
Treat: IV antibiotics (ceftriaxone, cefazolin) if systemic symptoms, amoxicillin if no systemic symptoms

Question 19

Nocardia

Answer 19

Partially acid-fast, gram positive, filamentous branching rods

Immunocompromised hosts, lung nodules and brain abscesses
Lung nodules without cavitation on CXR

Treatment: TMP-SMX

Question 20

HIV patient with fever, cough, abdominal pain, diarrhea, night sweats, and weight loss with exam and lab findings of splenomegaly, elevated alkaline phosphatase, and a CD4 count <50

Answer 20

Disseminated Mycobacterium avium complex

Prevent with azithromycin prophylaxis

Question 21

Isoniazid Induced Peripheral Neuropathy

Answer 21

Caused by pyroxidine (B6) deficiency

Numbness and tingling in a stocking glove distribution

Question 22

Mucormycosis

Answer 22

Risk factors: DM with DKA, hematologic malignancy, transplant
Manifestations: Acute, fever, nasal congestion with purulent discharge, headache, sinus pain
Diagnosis: necrotic invasion of the palate, orbit, and brain, sinus endoscopy with biopsies and cultures
Treatment: surgical debridement, liposomal amphotericin B

Question 23

What is the treatment of mucormycosis?

Answer 23

surgical debridement and liposomal amphotericin B