What is the recommended treatment for bacteremia?

From the Guidelines

The recommended treatment for bacteremia involves prompt administration of empiric broad-spectrum antibiotics after obtaining blood cultures, followed by targeted therapy once the causative organism and its susceptibilities are identified, with a treatment duration generally ranging from 7-14 days, depending on the source of infection, causative organism, and clinical response.

Key Considerations

• Initial empiric regimens typically include combinations such as vancomycin (15-20 mg/kg IV every 8-12 hours) plus an anti-pseudomonal beta-lactam like piperacillin-tazobactam (4.5g IV every 6-8 hours) or cefepime (2g IV every 8 hours) 1.
• For uncomplicated bacteremia, 7 days may be sufficient, while complicated cases like endocarditis require longer courses, as suggested by guidelines for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children 1.
• Source control is essential, which may involve removing infected catheters or draining abscesses, and supportive care including IV fluids, vasopressors if needed, and close monitoring of vital signs and organ function is crucial 1.
• Early treatment is vital as bacteremia can rapidly progress to sepsis and septic shock, with each hour of delay increasing mortality risk, emphasizing the need for prompt administration of effective IV antimicrobials within the first hour of recognition of septic shock or severe sepsis without septic shock 1.
• Antibiotic stewardship principles should be applied by narrowing therapy once culture results are available to reduce resistance development and adverse effects, with recommendations to reassess antimicrobial regimen daily for potential de-escalation 1.

Treatment Duration and Source Control

• The duration of therapy typically ranges from 7 to 10 days; longer courses may be appropriate in patients who have a slow clinical response, undrainable foci of infection, bacteremia with Staphylococcus aureus, some fungal and viral infections, or immunologic deficiencies, including neutropenia 1.
• A clinical assessment to identify the source and extent of the infection with elimination and/or debridement of other sites of infection should be conducted, and additional blood cultures 2–4 days after initial positive cultures and as needed thereafter are recommended to document clearance of bacteremia 1.

Recent Guidelines and Recommendations

• Recent guidelines suggest that combination therapy not be routinely used for ongoing treatment of most other serious infections, including bacteremia and sepsis without shock, but may be considered for septic shock, with de-escalation recommended within the first few days in response to clinical improvement and/or evidence of infection resolution 1.
• The use of cefazolin or an anti-staphylococcal penicillin (ASP) for MSSA, and vancomycin or daptomycin for methicillin-resistant S. aureus (MRSA), is recommended, with appropriate dosing and consideration of treatment duration based on the presence of high-risk features 1.

From the FDA Drug Label

Meropenem for injection has been found to be effective in eliminating concurrent bacteremia in association with bacterial meningitis. The recommended treatment for bacteremia is meropenem (IV), which has been found to be effective in eliminating concurrent bacteremia in association with bacterial meningitis 2.

• The dose for adult patients is 500 mg given every 8 hours for skin and skin structure infections and 1 gram given every 8 hours for intra-abdominal infections.
• For pediatric patients 3 months of age and older, the dose is 10 mg/kg, 20 mg/kg or 40 mg/kg every 8 hours (maximum dose is 2 grams every 8 hours), depending on the type of infection.
• Meropenem for injection should be administered by intravenous infusion over approximately 15 minutes to 30 minutes or as an intravenous bolus injection (5 mL to 20 mL) over approximately 3 minutes to 5 minutes 2.

From the Research

Treatment Options for Bacteremia

• The recommended treatment for bacteremia, specifically methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, includes vancomycin and daptomycin as initial treatment options 3.
• For persistent MRSA bacteremia or bacteremia due to vancomycin-intermediate or vancomycin-resistant strains, treatment options include daptomycin, ceftaroline, and combination therapies 3.
• The combination of vancomycin with piperacillin/tazobactam has been shown to be synergistic against MRSA, but may not be effective against unique MRSA strain types 4.

Broad-Spectrum Antimicrobials

• The treatment of serious bacterial infections, including bacteremia, often requires the use of broad-spectrum antimicrobials to "get it right up front" before the causative pathogen is identified 5.
• Initial empirical therapy with broad-spectrum antimicrobials can help reduce mortality, morbidity, and length of hospital stay, but also carries the risk of emergence of resistance 5.

Combination Therapies

• The combination of vancomycin with cefepime has been shown to improve clearance of MRSA bloodstream infections and may be useful as the β-lactam component of synergistic vancomycin + β-lactam regimens 6.
• However, the combination of vancomycin with piperacillin/tazobactam has been associated with an increased risk of acute kidney injury compared to other broad-spectrum antibiotic combinations 7.

Considerations for Treatment

• The choice of treatment for bacteremia should be guided by the severity of the infection, the susceptibility of the causative pathogen, and the potential risks and benefits of different treatment options 3, 4, 5, 6, 7.
• Clinicians should be vigilant when employing combination regimens, particularly those that include vancomycin and piperacillin/tazobactam, due to the increased risk of nephrotoxicity 7.