What is the recommended antibiotic prophylaxis (Antibiotic Prophylaxis) for colorectal surgery?

From the Guidelines

Intravenous antibiotic prophylaxis should be given within 60 min before incision as a single-dose administration to all patients undergoing colorectal surgery, and oral antibiotics should be added in patients receiving oral mechanical bowel preparation.

Recommended Antibiotic Regimen

The recommended regimen includes a combination of oral and intravenous medications to reduce the risk of surgical site infections.

• For intravenous prophylaxis, a cephalosporin in combination with metronidazole is the preferred option, with cefazolin 2g (or 3g for patients >120 kg) plus metronidazole 500mg administered within 60 minutes before surgical incision 1.
• For patients with beta-lactam allergies, alternatives include clindamycin 900mg plus gentamicin 5mg/kg or aztreonam 2g.
• For oral preparation, patients should take oral antibiotics, usually given 18–24 h before surgery, in addition to mechanical bowel preparation, to reduce the risk for surgical site infections when compared with intravenous coverage alone 1.

Rationale

The antibiotics target both aerobic and anaerobic bacteria commonly found in the colon, including Escherichia coli, Bacteroides fragilis, and other enteric organisms.

• This combined approach significantly reduces bacterial counts in the colon and provides systemic coverage during the procedure, decreasing surgical site infection rates by approximately 50% compared to intravenous antibiotics alone 1.
• Redosing may be necessary for procedures lasting more than 4 hours or with significant blood loss.

Skin Preparation

Skin disinfection should be performed using chlorhexidine–alcohol-based preparations 1.

• Evidence is insufficient to support advanced measures such as antiseptic showering, routine shaving and adhesive incise sheets 1.

From the FDA Drug Label

For surgical prophylactic use, to prevent postoperative infection in contaminated or potentially contaminated colorectal surgery, the recommended dosage schedule for adults is: a 15 mg/kg infused over 30 to 60 minutes and completed approximately one hour before surgery, followed by: b. 7. 5 mg/kg infused over 30 to 60 minutes at 6 and 12 hours after the initial dose The prophylactic administration of Metronidazole Injection preoperatively, intraoperatively, and postoperatively may reduce the incidence of postoperative infection in patients undergoing elective colorectal surgery which is classified as contaminated or potentially contaminated.

The recommended antibiotic prophylaxis for colorectal surgery is:

• Metronidazole: 15 mg/kg infused over 30 to 60 minutes, completed approximately one hour before surgery, followed by 7.5 mg/kg infused over 30 to 60 minutes at 6 and 12 hours after the initial dose 2 Alternatively, Cefoxitin may also be used for prophylactic use in colorectal surgery, with a dose of 2 grams administered intravenously just prior to surgery (approximately one-half to one hour before the initial incision) followed by 2 grams every 6 hours after the first dose for no more than 24 hours 3

From the Research

Antibiotic Prophylaxis for Colorectal Surgery

• The recommended antibiotic prophylaxis for colorectal surgery includes an antimicrobial agent with activity against both aerobes and anaerobes 4.
• For elective colorectal procedures, an orally administered three-dose regimen of neomycin/erythromycin is adequate 4.
• For nonelective colorectal surgery, cefoxitin is recommended 4.
• A single-dose oral ciprofloxacin plus parenteral metronidazole can be used as perioperative antibiotic prophylaxis in colorectal surgery 5.
• The combination of cefazoline and metronidazole is also commonly used, but it is essential to apply the correct dose and timing before operation to decrease surgical site infections (SSI) 6.

Specific Regimens

• Oral neomycin/erythromycin along with a short course of a systemic cephalosporin active against anaerobes is a popular prophylactic regimen 7.
• A single dose of cefotetan can be compared to multiple doses of cefoxitin for antimicrobial prophylaxis in colorectal surgery, with similar abdominal wound infection rates 8.
• The choice of antimicrobial prophylaxis should be based on efficacy, safety, and cost 4.

Key Considerations

• The risk of postoperative wound infection is higher in patients with prolonged duration of surgery (greater than 3.5 hours) and rectal resection 7.
• Severe contamination of the operative field can lead to infections despite antimicrobial prophylaxis 8.
• The timing of antibiotic administration is crucial, with application 20-30 minutes before incision recommended 6.