Empiric Antibiotic Choices for Sepsis

Introduction to Sepsis Management

The Surviving Sepsis Campaign recommends administering broad-spectrum intravenous antibiotics within 60 minutes of sepsis recognition, using combination therapy with an anti-pseudomonal β-lactam plus either an aminoglycoside or fluoroquinolone to cover all likely gram-negative and gram-positive pathogens 1, 2

Intravenous antimicrobials must be initiated within one hour of sepsis or septic shock recognition, as this is the single most critical intervention for reducing mortality 1, 2
Obtain at least two sets of blood cultures before antibiotics, but never delay antimicrobials beyond 45 minutes waiting for cultures 2

Use an anti-pseudomonal β-lactam plus either an aminoglycoside or a fluoroquinolone for patients with septic shock 2
Specific β-lactam options include piperacillin-tazobactam 2, cefepime 2, and meropenem 2
Add vancomycin or linezolid if MRSA is suspected, such as in healthcare-associated infection, known MRSA colonization, or severe skin/soft tissue infection 2
Add anidulafungin or caspofungin if risk factors for invasive candidiasis exist, including immunosuppression, prolonged ICU stay, total parenteral nutrition, or broad-spectrum antibiotic exposure 2

For Pseudomonas aeruginosa with respiratory failure and septic shock: Use extended-spectrum β-lactam plus aminoglycoside or fluoroquinolone 2
For bacteremic Streptococcus pneumoniae with septic shock: Use β-lactam plus macrolide combination 2

Use loading doses for vancomycin (25-30 mg/kg actual body weight) to rapidly achieve therapeutic levels in septic shock due to expanded extracellular volume from fluid resuscitation 2
Consider extended or continuous infusions of β-lactams after initial bolus to maximize time above MIC, particularly for resistant organisms 2

Reassess antimicrobial therapy daily for potential narrowing once pathogen identification and sensitivities are available 1, 2
Discontinue combination therapy within 3-5 days in response to clinical improvement and/or evidence of infection resolution 1, 2
Narrow to the most appropriate single therapy once susceptibility profile is known 1

7-10 days is adequate for most serious infections associated with sepsis and septic shock 1, 2
Longer courses are appropriate for slow clinical response 1, 2, undrainable foci of infection 1, 2, Staphylococcus aureus bacteremia 1, 2, and fungal and viral infections 1, 2

Benzylpenicillin (or ampicillin) plus gentamicin is the first-line empirical treatment for early-onset neonatal sepsis 3, 4, 5
For coagulase-negative staphylococci in late-onset neonatal sepsis: Vancomycin 3, 4
Ceftriaxone (plus ampicillin or amoxicillin in neonates up to 3 months) for older children with suspected sepsis 3, 4

Delayed administration: Mortality increases with each hour delay in appropriate antibiotic administration 1
Failure to de-escalate: Continuing broad-spectrum therapy unnecessarily increases resistance risk 1
Overlooking source control: Identify and address infection source within 12 hours when possible 1