From the Guidelines
Cefazolin is the preferred antibiotic for treating Methicillin-Susceptible Staphylococcus aureus (MSSA) infections.
Key Points
- Studies have shown superior outcomes of beta-lactams, such as cefazolin, for MSSA bloodstream infections when compared with vancomycin 1.
- Cefazolin has a preferable safety profile compared with anti-staphylococcal penicillins (ASPs) and large-scale observational data supports its efficacy 1.
- The concern about decreased efficacy of cefazolin in isolates with the cefazolin inoculum effect (CzIE) is uncertain and may not be a significant clinical implication 1.
- Cefazolin is a reasonable alternative for patients with a well-defined history of nonanaphylactoid reactions to penicillins, such as a simple skin rash 1.
- The American Heart Association suggests that nafcillin is the preferred agent for brain abscess complicating MSSA IE, but cefazolin can be used in other cases of MSSA IE 1.
Treatment Considerations
- Cefazolin can be used as empirical coverage for patients with IE caused by S aureus while awaiting susceptibility results, in combination with vancomycin if necessary 1.
- The usefulness of empiric combination therapy in patients with S aureus bacteremia until oxacillin susceptibility is known is uncertain, but beta-lactam–containing regimens have shown superiority over vancomycin monotherapy for bacteremic MSSA infections 1.
From the FDA Drug Label
Cefazolin for Injection, USP is indicated in the treatment of the following serious infections due to susceptible organisms: ... Skin and Skin Structure Infections: Due to S. aureus (including beta-lactamase-producing strains), S. pyogenes, and other strains of streptococci. Bone and Joint Infections: Due to S. aureus. Septicemia: Due to S. pneumoniae, S. aureus (including beta-lactamase-producing strains), P. mirabilis, E. coli. Endocarditis: Due to S. aureus (including beta-lactamase-producing strains) and S. pyogenes.
The preferred antibiotic for treating Methicillin-Susceptible Staphylococcus aureus (MSSA) infections is Cefazolin, as it is indicated for the treatment of serious infections due to susceptible organisms, including S. aureus. There is no direct information in the provided drug label that supports the use of Vancomycin as the preferred antibiotic for treating MSSA infections. 2
From the Research
Treatment of Methicillin-Susceptible Staphylococcus aureus (MSSA) Infections
- The preferred antibiotic for treating MSSA infections is a topic of discussion among researchers and clinicians.
- Studies have compared the effectiveness of different antibiotics, including cefazolin and vancomycin, in treating MSSA infections.
Comparison of Cefazolin and Vancomycin
- A study published in 2017 3 suggested that cefazolin is a suitable alternative to antistaphylococcal penicillins for the treatment of MSSA bacteremia, with similar clinical efficacy and better tolerability.
- Another study published in 2005 4 recommended penicillinase-resistant penicillins, such as flucloxacillin and dicloxacillin, as the antibiotics of choice for serious MSSA infections, while cefazolin and other cephalosporins may be used for less serious infections or in patients with penicillin hypersensitivity.
- A meta-analysis published in 2018 5 found that cefazolin was more effective and safer than antistaphylococcal penicillins in patients with MSSA bacteremia, with lower mortality rates and fewer adverse events.
- A retrospective cohort study published in 2011 6 found that patients who received nafcillin or cefazolin had lower mortality hazards compared to those who received vancomycin alone, and that switching from vancomycin to nafcillin or cefazolin was associated with improved survival.
- A comparative effectiveness study published in 2015 7 found that beta-lactams, including cefazolin, were superior to vancomycin for definitive therapy of MSSA bloodstream infections, with lower mortality rates.
Key Findings
- Cefazolin is a suitable alternative to antistaphylococcal penicillins for the treatment of MSSA bacteremia 3, 5.
- Vancomycin is not the preferred antibiotic for treating MSSA infections, due to its association with poorer outcomes and higher mortality rates 6, 7.
- Cefazolin and other beta-lactams are preferred for definitive therapy of MSSA bloodstream infections, while vancomycin may be used for empiric treatment 7.