From the Guidelines
Cefazolin has a superior mortality profile compared to Vancomycin in treating Methicillin-Sensitive 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.
- A high mortality rate among patients treated with vancomycin for pneumonia caused by MSSA has been described, with a mortality rate of approximately 47% 1.
- In contrast, patients with pneumonia caused by MSSA and receiving therapy with a beta-lactam, such as cefazolin, have a mortality rate of less than 5% 1.
- The preferable safety profile of cefazolin compared with vancomycin, and the availability of large-scale observational data supporting the efficacy of cefazolin, make it a comfortable choice for most patients with MSSA bacteremia 1.
Considerations
- The cefazolin inoculum effect (CzIE) has been raised as a concern, with some studies suggesting decreased efficacy of cefazolin in isolates with this effect 1.
- However, recent observational data suggest similar efficacy, or even a trend towards superiority of cefazolin over other antibiotics, such as anti-staphylococcal penicillins (ASPs) 1.
From the Research
Comparative Mortality Profile
The comparative mortality profile of Vancomycin versus Cefazolin in treating Methicillin-Sensitive Staphylococcus aureus (MSSA) infections is as follows:
- Studies have shown that Vancomycin may be inferior to β-lactams, such as Cefazolin, for the empiric treatment of MSSA bacteremia 2, 3, 4, 5.
- Adjusted mortality at 28 days was similar between the two groups in some studies (OR 0.85; 95% CI 0.27-2.67) 2, (OR: 1.14; 95% CI: 0.49-2.64) 3.
- However, other studies found that patients who received definitive therapy with a β-lactam, such as Cefazolin, had lower mortality compared to those who received Vancomycin (HR, 0.65; 95% CI, .52-.80) 4, (adjusted hazard ratio (HR): 0.21; 95% CI: 0.09,0.47) 5.
- The hazard of mortality decreased further for patients who received Cefazolin compared to Vancomycin (HR, 0.57; 95% CI, .46-.71) 4.
Key Findings
- Vancomycin monotherapy may be appropriate for the empiric treatment of MSSA bacteremia if definitive therapy with Cloxacillin or Cefazolin can be initiated within 3 days 3.
- Hemodialysis-dependent patients with MSSA bacteremia treated with Vancomycin are at a higher risk of experiencing treatment failure than those receiving Cefazolin 6.
- Patients who received empiric therapy with a β-lactam had similar mortality compared to those who received Vancomycin, but patients who received definitive therapy with a β-lactam had lower mortality 4.
Study Results
- A retrospective cohort study of 669 patients found that empiric β-lactams was associated with earlier clearance of bacteremia by a median of 1 day compared to Vancomycin 2.
- A retrospective cohort study of 814 patients found that no differences in secondary outcomes were observed between the two groups 3.
- A prospective study of 123 hemodialysis-dependent patients found that treatment failure was more common among patients receiving Vancomycin (31.2% vs. 13%; P=.02) 6.
- A retrospective cohort study of patients admitted to 122 hospitals found that patients who received definitive therapy with a β-lactam had 35% lower mortality compared to patients who received Vancomycin 4.
- A retrospective cohort study of 267 patients found that those receiving Nafcillin or Cefazolin had 79% lower mortality hazards compared to those who received Vancomycin alone (adjusted hazard ratio (HR): 0.21; 95% CI: 0.09,0.47) 5.