Antibiotic Therapy for Sepsis

Introduction to Antibiotic Selection

The Surviving Sepsis Campaign recommends administering broad-spectrum IV antibiotics within 60 minutes of recognizing sepsis or septic shock, using empiric therapy that covers all likely bacterial pathogens including gram-positive, gram-negative, and potentially resistant organisms 1, 2, 3

The Society of Critical Care Medicine suggests that IV antimicrobials must be initiated within one hour of recognition for both sepsis and septic shock, as this is the single most critical intervention for reducing mortality 1, 2, 3
The Infectious Diseases Society of America recommends obtaining at least two sets of blood cultures (aerobic and anaerobic) before antibiotics, but never delaying antimicrobials beyond 45 minutes waiting for cultures 4

The American Thoracic Society recommends using combination therapy with at least two antibiotics from different antimicrobial classes for septic shock, such as an anti-pseudomonal β-lactam PLUS either an aminoglycoside OR a fluoroquinolone 1, 2, 5
The Infectious Diseases Society of America suggests adding vancomycin or linezolid if MRSA is suspected, such as in healthcare-associated infection, known MRSA colonization, or severe skin/soft tissue infection 1, 7
The Society of Critical Care Medicine recommends adding antifungal coverage, such as anidulafungin or caspofungin, if risk factors for invasive candidiasis exist, such as immunosuppression, prolonged ICU stay, total parenteral nutrition, or broad-spectrum antibiotics 1, 2

The American College of Chest Physicians recommends using extended-spectrum β-lactam PLUS aminoglycoside or fluoroquinolone for Pseudomonas aeruginosa bacteremia with respiratory failure and septic shock 1, 2
The Infectious Diseases Society of America suggests using β-lactam PLUS macrolide combination for bacteremic Streptococcus pneumoniae with septic shock 1, 2

The Society of Critical Care Medicine recommends using loading doses for vancomycin, such as 25-30 mg/kg actual body weight, to rapidly achieve therapeutic levels in septic shock due to expanded extracellular volume from fluid resuscitation 6
The American College of Chest Physicians suggests considering extended or continuous infusions of β-lactams, after initial bolus, to maximize time above MIC, particularly for resistant organisms 6

The Surviving Sepsis Campaign recommends reassessing antimicrobial therapy daily for potential narrowing once pathogen identification and sensitivities are available 1, 7, 2, 4
The Infectious Diseases Society of America suggests discontinuing combination therapy within 3-5 days in response to clinical improvement and/or evidence of infection resolution 1, 7, 5

The Society of Critical Care Medicine recommends that 7-10 days is adequate for most serious infections associated with sepsis and septic shock 1, 7, 2
The American College of Chest Physicians suggests that longer courses are appropriate for slow clinical response, undrainable foci of infection, Staphylococcus aureus bacteremia, fungal and viral infections, and immunodeficiency including neutropenia 1, 7, 2