For a deep popliteal space injury, IV antibiotics are typically broad-spectrum to cover gram-positive organisms (skin flora like Staphylococcus, Streptococcus) and gram-negative rods, particularly if contamination is present. Common regimens include a beta-lactam/beta-lactamase inhibitor (e.g., piperacillin-tazobactam) or a combination of a cephalosporin plus metronidazole.