What is the treatment for Viridans streptococcus (a type of bacteria) bacteremia (presence of bacteria in the blood)?

From the Guidelines

The treatment of Viridans streptococcus bacteremia typically involves the administration of penicillin G, with a recommended dose of 12-18 million units per day, divided into 4-6 doses, for a duration of 4 weeks 1. Alternatively, ceftriaxone may be used at a dose of 2 grams every 24 hours for 4 weeks 1. In cases of penicillin allergy, vancomycin may be considered at a dose of 30 mg/kg per 24 hours, divided into 2 equally divided doses, for a duration of 4 weeks, with trough levels monitored to ensure therapeutic efficacy 1.

Key Considerations

• The choice of antibiotic regimen depends on the susceptibility of the Viridans streptococcus isolate to penicillin and other antibiotics 1.
• Patients with penicillin-resistant strains may require alternative regimens, such as combination therapy with gentamicin 1.
• Vancomycin is recommended only for patients who are unable to tolerate penicillin or ceftriaxone 1.
• Pediatric doses should not exceed those of normal adults, and should be adjusted according to renal function and other factors 1.

Antibiotic Regimens

• Penicillin G: 12-18 million units per day, divided into 4-6 doses, for 4 weeks 1.
• Ceftriaxone: 2 grams every 24 hours, for 4 weeks 1.
• Vancomycin: 30 mg/kg per 24 hours, divided into 2 equally divided doses, for 4 weeks, with trough levels monitored to ensure therapeutic efficacy 1.
• Gentamicin: 3 mg/kg per 24 hours, for 2 weeks, in combination with penicillin or ceftriaxone for penicillin-resistant strains 1.

From the Research

Treatment for Viridans Streptococcus Bacteremia

• The optimal treatment for Viridans streptococcus bacteremia is not explicitly stated in the provided studies, but some studies suggest that antibiotic therapy such as ceftriaxone or vancomycin may be effective 2, 3, 4.
• A study on short-course treatment of bacteremia with ceftriaxone monotherapy found that 57 out of 92 evaluable infections had successful results, with no significant differences between different dosing schedules 2.
• Another study reported a case of Viridans streptococcal mitral valve subacute bacterial endocarditis (SBE) in a patient with mitral valve prolapse, where the patient was given optimal antibiotic treatment with ceftriaxone plus gentamicin, but failed to respond to antimicrobial therapy 3.
• A study on endocarditis caused by highly penicillin-resistant Viridans group streptococci found that vancomycin-based regimens may be effective, and that combinations of gentamicin with β-lactams or vancomycin were more active than their respective monotherapies 4.

Antibiotic Options

• Ceftriaxone: may be effective for short-course treatment of bacteremia 2 and for treatment of Viridans streptococcal SBE 3.
• Vancomycin: may be effective for treatment of highly penicillin-resistant Viridans group streptococci endocarditis 4.
• Gentamicin: may be used in combination with β-lactams or vancomycin to increase bacterial eradication 4.

Important Considerations

• Antibiotic prophylaxis may be important for patients with certain cardiac lesions, such as mitral valve prolapse, to prevent SBE 3.
• The emergence of high-level daptomycin resistance among Viridans group streptococci strains warrants caution in the use of daptomycin therapy for VGS IE 4.