What is the treatment for gram-positive cocci found in a blood culture?

From the Guidelines

For a blood culture showing gram-positive cocci, empiric treatment should begin with vancomycin 15-20 mg/kg IV every 8-12 hours while awaiting final culture identification and susceptibility results, as recommended by the Infectious Diseases Society of America 1. This approach covers both Staphylococcus species (including methicillin-resistant S. aureus) and Streptococcus species. For severe infections or sepsis, consider adding ceftriaxone 2g IV daily to broaden coverage. Once the specific organism and susceptibilities are identified, therapy should be narrowed. Some key points to consider in the management of such infections include:

• The choice of antibiotics targets the cell wall synthesis of gram-positive bacteria, with vancomycin binding to D-alanyl-D-alanine residues to prevent proper peptidoglycan cross-linking, while beta-lactams inhibit transpeptidase enzymes needed for cell wall assembly.
• Empirical antibiotic therapy should include vancomycin and coverage for gram-negative bacilli, based on the local antibiogram, as suggested by 1 and 1.
• Patients who receive empirical vancomycin and who are found to have CRBSI due to methicillin-susceptible S. aureus should be switched to cefazolin, according to 1 and 1.
• Treatment duration typically ranges from 10-14 days for uncomplicated bacteremia to 4-6 weeks for endocarditis or other deep-seated infections, with the specific duration guided by the clinical context and the presence of any complications, as outlined in 1 and 1. Blood cultures should be repeated to confirm clearance of the infection. It's also important to consider the potential for drug-resistant pathogens and to adjust the treatment regimen accordingly, based on the most recent and highest quality evidence available, such as that provided by 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Ceftriaxone may be administered intravenously or intramuscularly. The usual adult daily dose is 1 to 2 grams given once a day (or in equally divided doses twice a day) depending on the type and severity of infection. For the treatment of skin and skin structure infections, the recommended total daily dose is 50 to 75 mg/kg given once a day (or in equally divided doses twice a day). For the treatment of serious miscellaneous infections other than meningitis, the recommended total daily dose is 50 to 75 mg/kg, given in divided doses every 12 hours.

Ceftriaxone can be used to treat infections caused by Gram-positive cocci, including Streptococcus and Staphylococcus species.

• The dosage of ceftriaxone for the treatment of infections caused by Gram-positive cocci is 1 to 2 grams per day for adults, and 50 to 75 mg/kg per day for pediatric patients.
• The treatment duration is usually 7 to 14 days, but may be longer for complicated infections. 2

PRECAUTIONS General Nafcillin should generally not be administered to patients with a history of sensitivity to any penicillin. Penicillin should be used with caution in individuals with histories of significant allergies and/or asthma Laboratory Tests Bacteriologic studies to determine the causative organisms and their susceptibility to the penicillinase-resistant penicillins should be performed

Nafcillin can be used to treat infections caused by Gram-positive cocci, including Staphylococcus species.

• The dosage of nafcillin is not specified in the provided text for the treatment of infections caused by Gram-positive cocci.
• Nafcillin should be used with caution in patients with a history of penicillin allergy or significant allergies and/or asthma. 3

From the Research

Blood Culture Gram Posting Cocci Medication Treatment

• The treatment of Staphylococcus aureus bacteremia typically includes antibiotics active against MRSA, such as vancomycin or daptomycin 4.
• Once antibiotic susceptibility results are available, antibiotics should be adjusted, with cefazolin or antistaphylococcal penicillins used for MSSA and vancomycin, daptomycin, or ceftobiprole for MRSA 4.
• The combination of vancomycin and nafcillin has been shown to be effective against hVISA, MRSA, and MSSA, with synergy observed in 92% of strains in one study 5.
• A treatment algorithm for streptococci and enterococci from positive blood cultures identified with the Verigene Gram-positive blood culture assay has been developed, allowing for targeted treatment 6.
• Gram-positive cocci in clusters strongly suggest Staphylococci, and "in-chains" indicates Streptococci or Enterococci, guiding the selection of appropriate antimicrobial agents 7.
• The high prevalence of MRSA has led clinicians to select antibiotics that have coverage against MRSA, usually vancomycin, for empiric therapy for suspected staphylococcal infections, but vancomycin has been associated with poor outcomes such as nephrotoxicity, persistent bacteremia, and treatment failure 8.
• Nafcillin or cefazolin has been shown to have a lower mortality hazard compared to vancomycin alone in the treatment of MSSA bacteremia, with a 79% lower mortality hazard observed in one study 8.