From the Guidelines
Vancomycin has a higher mortality profile compared to Cefazolin for Methicillin-Sensitive Staphylococcus aureus (MSSA) bacteremia.
Key Points
- Studies have shown superior outcomes of beta-lactams, such as cefazolin, for MSSA bloodstream infections when compared with vancomycin 1.
- The use of cefazolin is preferable due to its safety profile and efficacy, despite concerns about the cefazolin inoculum effect (CzIE) 1.
- Observational data suggest similar efficacy, or even a trend towards superiority of cefazolin over anti-staphylococcal penicillins (ASPs) 1.
- A meta-analysis demonstrated the superiority of β-lactam–containing regimens over vancomycin monotherapy for bacteremic MSSA infections, including infective endocarditis 1.
- Vancomycin is less effective for the treatment of MSSA bacteremia and endocarditis compared to β-lactam agents 1.
Mortality Comparison
- A study found higher 30-day mortality (39.5% vs 15.2%) in isolates positive for the CzIE, but it is unclear whether antibiotic selection would ameliorate this association 1.
- The mortality rates for MRSA endocarditis are 30%–37%, but the comparison with MSSA is not directly provided in the evidence 1.
Treatment Recommendations
- Cefazolin is a suitable option for the treatment of MSSA bacteremia, considering its efficacy and safety profile 1.
- Nafcillin is the preferred agent for brain abscess complicating MSSA infective endocarditis, but vancomycin can be used if the patient cannot tolerate nafcillin therapy 1.
From the Research
Mortality Profile Comparison
- The mortality profile comparison between Vancomycin and Cefazolin for Methicillin-Sensitive Staphylococcus aureus (MSSA) bacteremia has been studied in several research papers 2, 3, 4, 5, 6.
- A retrospective cohort study found that empiric therapy with β-lactams (including cefazolin) was not associated with differences in all-cause mortality compared to vancomycin 2.
- A meta-analysis found that all-cause 90-day mortality was lower in patients who received cefazolin compared to antistaphylococcal penicillins (OR 0.63,95% CI 0.41-0.99) 3.
- Another study found that adjusted mortality at 28 days was similar between patients who received empiric β-lactams (including cefazolin) and those who received vancomycin (OR 0.85; 95% CI 0.27-2.67) 5.
- A comparative effectiveness study found that patients who received definitive therapy with a beta-lactam (including cefazolin) had 35% lower mortality compared to patients who received vancomycin (HR, 0.65; 95% CI, 0.52-0.80) 6.
Secondary Outcomes
- A study found that there were no differences in secondary outcomes, including recurrent infection at 6 months, duration of bacteremia, and hospital length-of-stay, between patients who received empiric β-lactams (including cefazolin) and those who received vancomycin 2.
- Another study found that the duration of bacteremia was longer in the vancomycin group compared to the β-lactam group (97.1 vs 70.7 hours, p = 0.007) 5.
- A meta-analysis found that odds of discontinuation due to adverse events was significantly lower in patients receiving cefazolin compared to antistaphylococcal penicillins (OR 0.25,95% CI 0.11-0.56) 3.
Treatment Recommendations
- The studies suggest that cefazolin may be a suitable alternative to vancomycin for the treatment of MSSA bacteremia, especially when definitive therapy can be initiated within 3 days 2, 6.
- Cefazolin may offer several pharmacologic advantages over antistaphylococcal penicillins, including more convenient dosing regimens and better tolerability 4.