From the Guidelines
For 1+ Gram Positive Cocci infections, vancomycin is the preferred antibiotic choice, with a recommended dose of 40 mg·kg−1·d−1 IV divided every 8–12 h up to 2 g daily, as stated in the 2015 update from the American Heart Association 1.
Key Considerations
- Vancomycin remains the cornerstone therapy for serious methicillin-resistant Staphylococcus aureus (MRSA) infections.
- The dose of vancomycin should be adjusted to achieve target trough levels of 15-20 μg/mL for invasive infections.
- Alternative antibiotic choices, such as cefazolin or nafcillin/oxacillin, may be considered for less severe infections or known methicillin-sensitive strains.
- The treatment duration typically ranges from 7-14 days for uncomplicated infections to 4-6 weeks for endocarditis or osteomyelitis.
Antibiotic Options
- Vancomycin: 40 mg·kg−1·d−1 IV divided every 8–12 h up to 2 g daily 1.
- Cefazolin: 100 mg·kg−1·d−1 IV divided every 8 h up to 12 g daily 1.
- Nafcillin/Oxacillin: 200 mg·kg−1·d−1 IV divided every 4–6 h up to 12 g/d 1.
Important Notes
- The 2002 guidelines for the use of antimicrobial agents in neutropenic patients with cancer suggest that vancomycin may be incorporated into initial therapeutic regimens for high-risk patients, but discontinued 24–48 hours later if no gram-positive infection is identified 1.
- The choice of antibiotic should be guided by the severity of the infection, the susceptibility of the organism, and the potential for resistance.
From the FDA Drug Label
Daptomycin has been shown to be active against most isolates of the following microorganisms both in vitro and in clinical infections Gram-Positive Bacteria Enterococcus faecalis (vancomycin-susceptible isolates only) Staphylococcus aureus (including methicillin-resistant isolates) Streptococcus agalactiae Streptococcus dysgalactiae subsp. equisimilis Streptococcus pyogenes
The best antibiotic choices for Gram-Positive Cocci infections, specifically those caused by Staphylococcus and Streptococcus species, include:
- Daptomycin
- Vancomycin
- Anti-staphylococcal semi-synthetic penicillins (e.g., nafcillin, oxacillin, cloxacillin, or flucloxacillin) 2 Note that the choice of antibiotic should be based on the specific type of infection, the severity of the infection, and the patient's medical history and allergies.
From the Research
Antibiotic Options for Gram-Positive Cocci
- For methicillin-resistant Staphylococcus aureus (MRSA) infections, options include:
- Linezolid, which is comparable to vancomycin in patients with MRSA pneumonia 3, 4
- Daptomycin, which has rapid bactericidal activity for Staphylococcus aureus and is approved for use in bacteremia and right-sided endocarditis 3, 4
- Tigecycline, which has activity against both Enterococcus species and MRSA, and is also active against Enterobacteriaceae and anaerobes 3, 4
- For vancomycin-resistant Enterococcus faecium infections, Quinupristin/dalfopristin is the drug of choice 3
- Newer glycopeptides, such as dalbavancin, telavancin, and oritavancin, have superior pharmacodynamic properties compared to vancomycin 3, 4
Considerations for Antibiotic Use
- Vancomycin remains an important first-line antimicrobial for treatment of serious MRSA infections, but its use may be limited by increasing minimum inhibitory concentrations and the presence of vancomycin-intermediate S. aureus 5
- Continuous infusion of antibiotics may provide theoretical benefits, but clinical trials demonstrating superiority in outcomes are uncommon 5
- The use of newer antibiotics, such as linezolid, daptomycin, and tigecycline, may be considered in the "post-vancomycin" era, but solid clinical evidence supporting their use is limited 6
Resistance Patterns
- Gram-positive cocci, such as Staphylococcus aureus and enterococci, are able to acquire resistance to frequently used drugs rapidly through selective pressure and genetic evolution 7
- Methicillin-resistant staphylococci and vancomycin-resistant enterococci are common causes of nosocomial infections and can be difficult to treat due to high levels of resistance to multiple antibiotics 7