Preoperative prophylaxis: practical steps to prevent surgical site infection

Preoperative prophylaxis means giving the right drug, at the right time, to lower the risk of infection after surgery. The goal is simple: reduce bacteria at the incision site when the wound is fresh. That prevents extra antibiotics later, shorter hospital stays, and fewer complications.

Choose the right antibiotic based on the procedure. For most clean and clean-contaminated surgeries, cefazolin is the go-to choice because it covers common skin bugs. For procedures with bowel contamination, add agents that cover gram negatives and anaerobes. If a patient has a true penicillin allergy, use clindamycin or vancomycin depending on the organisms to cover.

Timing matters more than many realize. Give the usual dose within 60 minutes before skin incision. Vancomycin and fluoroquinolones need a longer infusion, so start them up to 120 minutes before incision. If surgery lasts longer than two half-lives of the drug, give another dose intraoperatively to keep protective levels.

Adjust doses by weight and kidney function. Obese patients often need a higher cefazolin dose (for example, 2 g or 3 g depending on weight) to reach effective tissue levels. Patients with renal impairment often need lower doses or spacing. Talk with pharmacy on complex cases.

Screening and decolonization help in high-risk patients. Nasal MRSA carriers benefit from mupirocin ointment plus chlorhexidine showers before surgery. Many hospitals use a short decolonization protocol for certain implants or cardiac surgeries to cut infection risk.

Small perioperative measures add up. Use chlorhexidine for skin prep rather than alcohol-free alternatives. Avoid shaving with razors; clip hair if needed. Keep blood glucose under control in the perioperative period, especially for diabetic patients. Stop or manage blood thinners safely before surgery following a plan with the surgeon and anesthetist.

Don’t extend antibiotics beyond what’s needed. Most clean surgeries need a single preoperative dose; continuing antibiotics after skin closure rarely helps and raises resistance risk. When drains or prosthetic implants are involved, follow specific guidance rather than default extended therapy.

Communicate clearly with the team. Make antibiotic choice, time of administration, and any allergy notes part of the surgical checklist. Pharmacy input, anesthesiology timing, and nursing reminders make it reliable.

Simple checklist for preoperative prophylaxis:

Confirm planned antibiotic and dose.

Give antibiotic within 60 minutes of incision (120 for vancomycin).

Adjust dose for weight and kidney function.

Use chlorhexidine skin prep and avoid razors.

Apply MRSA decolonization when indicated.

Stop routine postoperative antibiotics unless indicated.

Follow local and international guidelines and adapt for your setting. Small, consistent steps cut infections and improve outcomes.

If you are a patient, ask when your antibiotic will be given and tell the team about allergies, previous MRSA, or recent antibiotic use. If you are a clinician, document timing in the chart and use reminders on the operating room board. Simple checks before incision save patients time, money, and pain. Hospitals that track timing and adherence usually see lower surgical site infection rates. Ask questions; prevention is a team effort every time.