Management of Staphylococcus aureus Bacteremia

Initial Empirical Treatment

The Infectious Diseases Society of America recommends starting empirical therapy with vancomycin or daptomycin while awaiting susceptibility results, as these agents cover MRSA 3
Vancomycin dosing is recommended at 30-60 mg/kg/day IV in 2-4 divided doses, with a target trough of 15-20 mcg/mL for serious infections 1
Daptomycin dosing is recommended at 6 mg/kg IV once daily for bacteremia, with some experts suggesting 8-10 mg/kg for complicated cases 2

For MRSA, the American College of Physicians recommends continuing vancomycin (30-60 mg/kg/day) or daptomycin (6 mg/kg for uncomplicated, up to 10 mg/kg for complicated bacteremia) 1, 2
For persistent MRSA bacteremia or concern for antibiotic failure, the Infectious Diseases Society of America suggests considering combination therapy with daptomycin plus ceftaroline 4, 5

Every patient with S. aureus bacteremia requires a thorough history and physical examination, including assessment for metastatic infection, and infectious diseases consultation improves outcomes 4, 6
Follow-up blood cultures at 2-4 days after initiating therapy are necessary to document clearance, and echocardiography (at minimum transthoracic echocardiography) is required for all patients 4, 6, 2

The American Heart Association recommends obtaining TTE in all patients with S. aureus bacteremia, and proceeding directly to transesophageal echocardiography (TEE) in high-risk patients 6, 4, 5
TEE has superior sensitivity (vs. TTE: 32-82%) for detecting vegetations, intracardiac abscesses, and prosthetic valve involvement 4

Low-risk (uncomplicated) SAB should be treated for 14 days, while high-risk (complicated) SAB requires treatment for 4-6 weeks 4, 5, 7, 2
The Infectious Diseases Society of America recommends treating indeterminate-risk SAB for 4-6 weeks if metastatic infection cannot be excluded 4, 5

The Society for Healthcare Epidemiology of America emphasizes that source control is critical and must be addressed immediately, including removal of all removable infected intravascular catheters and devices, drainage of all identified abscesses, and debridement of infected tissues 3, 4, 2

The American College of Physicians recommends obtaining repeat blood cultures at 2-4 days after starting therapy, as persistent bacteremia significantly increases mortality 4, 6, 2
Reassessment of source control, TEE to evaluate for endocarditis, and additional imaging for metastatic foci are necessary for persistent bacteremia 6, 2

For adults with creatinine clearance <30 mL/min, vancomycin dosing should be based on levels, and daptomycin dosing should be adjusted to 4 mg/kg every 48 hours (for skin/soft tissue) or 6 mg/kg every 48 hours (for bacteremia) 2