Category Archives: Antimicrobial Review

Back to Basics // Introduction to Antibiotics with Dr. Cutrell

At noon conference today, Dr. James Cutrell kicked off our “Back to Basics” series with a great introduction to antibiotics and the concept of antibiotic stewardship. Check out the slides below & stay tuned for the sequel later this month!

Also, click below to read the perspective piece from NEJM by Drs. Nathan & Cars regarding antibiotic resistance.

Antimicrobial Resistance – Problems, Progress, and Prospects

Empiric Antibiotics: Vancomycin-Resistant Enterococcus


  • GI or GU infections in patients with prior abx
  • Bacteremia, endocarditis in those with extensive HC exposure
  • E. faecalis: Often remains sensitive to ampicillin, beta-lactams
  • E. faecium: Often multi-drug resistant

Cystitis Rx

  • Consider Nitrofurantoin or Fosfomycin

Invasive infections Rx

  • Amp-sens VRE faecalis: Amp, Amp/Sulb, Pip/Tazo, Imi/Meropenem active
  • Linezolid, High dose Daptomycin (8-12 mg/kg daily), Tigecycline à Consult ID for assistance

Empiric Antibiotics: MRSA (HINT: not just Vanc!)


  • Uncomplicated Bacteremia
    • Must meet all of following: No IE (by TEE); No prostheses; Negative f/u blood cultures at 2-4 days; Defervescence within 72 h of effective therapy; No metastatic infection
    • Vancomycin or Daptomycin for minimum 2 weeks
  • Complicated Bacteremia or Endocarditis
    • 4-6 weeks at minimum
    • No benefit to adding gentamicin or rifampin for native valve IE
  • Treatment Failure
    • Generally defined as persistent bacteremia around day 7 of therapy (median time to clearance of MRSA bacteremia is 7-9 days)
    • May also define failure as patient getting worse on current tx
    • Remember SOURCE CONTROL!!!

Antibiotic Choices

  • MRSA Abx
  • PO options acceptable for SSTI or completion of osteo Rx; IV preferred for invasive disease
  • Vancomycin is the empiric drug of choice in most serious infections (duh!)
    • Vanc MIC ≥ 2 associated with higher rates of Rx failure so consider alternative agents
  • If vancomycin intolerance or failure:
    • PNA: Linezolid, Ceftaroline
    • Bacteremia/Endocarditis: Daptomycin, Ceftaroline
    • CNS: Linezolid
    • Osteo: Dapto, Ceftaroline

Empiric Antibiotics: Septic Shock


  • Goal is “the administration of effective IV abx within 1st hour of recognition of septic shock or severe sepsis.” — (grade 1B and 1C, respectively)
  • Initial empiric Rx should include “one or more drugs active against all likely pathogens with adequate penetration into tissues presumed to be source of sepsis.” — (grade 1B)
  • Abx should be “reassessed daily for potential de-escalation.” — (grade 1B)
  • Combination therapy, when used empirically for severe sepsis, should not be continued more than 3-5 days” but de-escalate to single-agent therapy as soon as susceptibilities are known.” — (grade 2B)
  • Source control in first 12 hours if feasible. — (grade 1C)

Empiric Therapy

  • Empiric Rx depends on host factors, recent abx exposure, allergies, clinical syndrome and likely site of infection, local antibiogram and pt’s prior infections or colonization
  • Combination therapy recommended in neutropenics with severe sepsis, those with prior MDR pathogens, and respiratory failure or septic shock patients. — (grade 2B)
  • Practically, this usually means vancomycin + anti-Pseudomonal beta-lactam + either aminoglycoside or anti-Pseudomonal FQ


Continue reading Empiric Antibiotics: Septic Shock

Which dose do I use for that infection?

Sometimes it’s hard to remember all the dosing of those antibiotics and their indications for infections, particularly CNS and abscesses. Click on the links below to open a quick reference guide in how to treat these infections!




Special thanks to Ramu, MariAlison, and Parker for creating this blog post!