Prophylactic Antibiotics in Gut Surgery

Wound infections occur after as many as 50% of gastrointestinal operations. Single dose or short regimes of prophylactic antibiotics before gastrointestinal surgery have been shown to be as effective as more prolonged regimes and less likely to cause side-effects such as colitis.¹

• Patient related factors:
  • Extremes of age
  • Poor nutritional state
  • Obesity
  • Diabetes mellitus
  • Smoking
  • Coexisting infections at other sites
  • Bacterial colonisation, e.g. nasal colonisation with Staphylococcus aureus
  • Immunosuppression
  • Prolonged post-operative stay
• Operation related factors:
  • Length of surgical scrub
  • Length of operation
  • Operating theatre ventilation
  • Inadequate instrument sterilisation
  • Foreign material in surgical site
  • Surgical drains
  • Surgical technique including haemostasis, poor closure, tissue trauma
  • Post-operative hypothermia

• Oesophageal, gastric and duodenal surgery
• Insertion of percutaneous endoscopic gastrostomy (PEG)
• Small intestine surgery
• Bile duct surgery
• Pancreatic surgery
• Liver surgery
• Open gall bladder surgery (prophylaxis is not recommended for laparoscopic gall bladder surgery but should be considered in high-risk patients)
• Appendicectomy (highly recommended)
• Colorectal surgery (highly recommended)
• Open or laparoscopic surgery with mesh; antibiotic prof lacks this is not recommended but should be considered in high-risk patients (see above)
• Therapeutic endoscopic procedures (endoscopic retrograde cholangiopancreatography and percutaneous endoscopic gastrostomy); antibiotic prophylaxis should be considered in high-risk patients, i.e. pancreatic pseudo-cyst, immunosuppression, incomplete biliary drainage

Antibiotic prophylaxis is not recommended for inguinal or femoral hernia repair or for diagnostic endoscopic procedures.

• Prophylactic antibiotics for surgical procedures should be administered intravenously.²
• Intravenous prophylactic antibiotics should be given within the 30 minutes before the skin is incised.²
• A single dose of prophylactic antibiotic is all that is required except in special circumstances, e.g. prolonged surgery, major blood loss.²
• The precise regime will depend on the nature of the surgery, the individual situation of the patient e.g. drug allergies, and findings at operation e.g. perforated appendix.
• However it is essential to follow local guidelines to take account of local resistance patterns.
• Narrow spectrum, less expensive antibiotics should be the first choice for prophylaxis during surgery.²
• The likely organisms are anaerobes in appendicectomy and coliforms in biliary tract surgery. Antibiotics selected for prophylaxis in colorectal surgery should be active against both aerobic and anaerobic bacteria.¹
• Typical prophylactic regimes include:
  • Stomach or oesophagus - gentamicin or cefuroxime
  • Open biliary surgery - metronidazole and either cefuroxime or gentamicin
  • Colorectal surgery or appendicectomy - gentamicin or cefuroxime with metronidazole,⁴ or co-amoxiclav alone
  • Endoscopic retrograde cholangiopancreatography - gentamicin or ciprofloxacin

• Prolonged or inappropriate use of antibiotics may encourage the emergence of resistant strains of organisms.
• An additional problem is the increase in the number of cases of pseudomembranous colitis caused by Clostridium difficile.
• The prevalence of C. difficile infection is related to total antibiotic usage and, in particular, to the use of third generation cephalosporins.
• Although even single dose prophylaxis increases the risk of carriage of C. difficile, the risk is much greater in patients who receive prophylaxis for more than 24 hours.
• Longer courses of prophylactic antibiotics have also been associated with an increase in the frequency of bacteraemia and line infections.