What is the management of Strep sanguinis (Streptococcus sanguinis) bacteraemia?

Management of Streptococcus sanguinis Bacteremia

Streptococcus sanguinis bacteremia should be treated with intravenous penicillin G as first-line therapy, with vancomycin plus gentamicin as an alternative for penicillin-resistant strains or patients with severe penicillin allergy. 1

Etiology and Clinical Presentation

• Streptococcus sanguinis (formerly S. sanguis) is a viridans group streptococcus that commonly colonizes the oral cavity and is part of normal dental plaque 1
• It can enter the bloodstream through dental procedures, poor oral hygiene, or mucosal breaches, causing transient or persistent bacteremia 2
• Common clinical presentations include fever, chills, and symptoms related to potential metastatic infections 3
• S. sanguinis bacteremia has a significant association with infective endocarditis, particularly in patients with pre-existing valvular disease 1, 2

Diagnostic Approach

• Blood cultures are the gold standard for diagnosis, with at least two sets recommended before initiating antibiotics 3
• Echocardiography is essential to rule out endocarditis:
  • Transthoracic echocardiography (TTE) should be performed in all patients with S. sanguinis bacteremia 3
  • Transesophageal echocardiography (TEE) is indicated for patients with persistent bacteremia, prosthetic valves, or high clinical suspicion of endocarditis despite negative TTE 3
• Additional imaging may be needed based on clinical presentation to identify potential metastatic infections 3

Antimicrobial Treatment

First-line therapy:

• Penicillin G: 12-20 million units/day IV divided every 4-6 hours for uncomplicated bacteremia; extend to 4-6 weeks for endocarditis 4
• Ampicillin: 2g IV every 4-6 hours as an alternative to penicillin G 5

For penicillin-resistant strains or severe penicillin allergy:

• Vancomycin: 15-20 mg/kg IV every 8-12 hours (not to exceed 2g per dose) 1
• Consider adding gentamicin for synergistic effect, particularly in endocarditis cases 1

Alternative regimens:

• Ceftriaxone: 2g IV daily for penicillin-susceptible isolates in patients with non-anaphylactic penicillin allergy 6
• Teicoplanin or daptomycin: May be effective based on susceptibility testing 1

Duration of Therapy

• Uncomplicated bacteremia: 10-14 days of IV antibiotics 7
• Bacteremia with endocarditis: 4-6 weeks of IV antibiotics 4, 1
• Bacteremia with other metastatic infections (bone/joint, etc.): 2-6 weeks depending on the site and clinical response 8

Source Control and Management of Complications

• Identify and address the source of infection (dental abscess, endocarditis, etc.) 2
• Early infectious disease consultation is strongly recommended as it significantly improves outcomes (HR 0.29; CI: 0.17-0.48) 2
• For endocarditis, surgical evaluation may be necessary, especially with valvular dysfunction, persistent bacteremia, or embolic events 1
• Monitor for potential complications:
  • Septic emboli to brain, lungs, spleen, or kidneys 3
  • Metastatic abscesses 3
  • Septic arthritis or osteomyelitis 8

Monitoring and Follow-up

• Daily clinical assessment for treatment response (fever resolution, hemodynamic stability) 2
• Follow-up blood cultures at 48-72 hours to document clearance of bacteremia 3
• Repeat blood cultures if there is persistent fever or clinical deterioration 3
• Consider repeat echocardiography if there is clinical suspicion of endocarditis development during treatment 3

Prevention

• Good oral hygiene and regular dental care 8
• Antibiotic prophylaxis for dental procedures in high-risk patients (prosthetic valves, previous endocarditis) 8
• Prompt treatment of dental infections 8

Special Considerations

• Patients with prosthetic valves or devices require more aggressive evaluation and longer treatment courses 1
• Elderly patients (>75 years) have higher mortality rates and may require more intensive monitoring 8
• Immunocompromised patients may need broader empiric coverage until susceptibilities are available 3

Remember that early appropriate antimicrobial therapy and infectious disease consultation are key factors associated with improved outcomes in streptococcal bacteremia 2.