Final answer:
Cefazolin (Ancef) is the best cephalosporin to use for prophylactic antibiotic coverage of Gram positive Staphylococcus aureus in orthopedic surgery.
Step-by-step explanation:
The best cephalosporin to use to cover Gram positive Staphylococcus aureus in a prophylactic antibiotic for orthopedic surgery would be cefazolin (Ancef), which is a 1st generation cephalosporin. Cefazolin is effective against many strains of Staphylococcus aureus and is commonly used for prophylaxis in surgical procedures due to its broad spectrum of action and low toxicity. Its mode of action involves inhibiting cell wall synthesis in both Gram-positive and Gram-negative bacteria, making it suitable for coverage against Staphylococcus aureus.