Cefazolin (Ancef) is a first generation cephalosporin and arguably the most common antibiotic used for surgical prophylaxis (typically for skin flora). It provides gram positive coverage but only minor gram negative coverage.
As a general teaching, the risk of cross-reaction between cephalosporins and penicillins regarding allergies (don’t forget anaphylaxis) decreases with each generation. In other words, cefazolin (1st generation) has a higher risk than cefepime (4th generation).
Another important consideration: when vancomycin is pre-emptively started for Staphylococcus coverage in patients at high risk for methicillin-resistant Staphylococcus aureus (MRSA) and the organism ends up being SENSITIVE to methicillin (MSSA), we know to transition vancomycin to either nafcillin/oxacillin. In reality, the data shows that cefazolin is a better option with MSSA bacteremia with regards to mortality, but might not impact the recurrence of MSSA bacteremia compared to nafcillin and oxacillin.
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